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Sample records for modeling urban taxi

  1. Uncovering urban human mobility from large scale taxi GPS data

    Science.gov (United States)

    Tang, Jinjun; Liu, Fang; Wang, Yinhai; Wang, Hua

    2015-11-01

    Taxi GPS trajectories data contain massive spatial and temporal information of urban human activity and mobility. Taking taxi as mobile sensors, the information derived from taxi trips benefits the city and transportation planning. The original data used in study are collected from more than 1100 taxi drivers in Harbin city. We firstly divide the city area into 400 different transportation districts and analyze the origin and destination distribution in urban area on weekday and weekend. The Density-Based Spatial Clustering of Applications with Noise (DBSCAN) algorithm is used to cluster pick-up and drop-off locations. Furthermore, four spatial interaction models are calibrated and compared based on trajectories in shopping center of Harbin city to study the pick-up location searching behavior. By extracting taxi trips from GPS data, travel distance, time and average speed in occupied and non-occupied status are then used to investigate human mobility. Finally, we use observed OD matrix of center area in Harbin city to model the traffic distribution patterns based on entropy-maximizing method, and the estimation performance verify its effectiveness in case study.

  2. Exploring Urban Taxi Drivers’ Activity Distribution Based on GPS Data

    Directory of Open Access Journals (Sweden)

    Xiaowei Hu

    2014-01-01

    Full Text Available With the rapid development of information communication technology and data mining technology, we can obtain taxi vehicle’s real time operation status through the large-scale taxi GPS trajectories data and explore the drivers’ activity distribution characteristics. Based on the 204 continuous hours of 3198 taxi vehicles’ operation data of Shenzhen, China, this paper analyzed the urban taxi driver’s activity distribution characteristics from different temporal and spatial levels. In the time level, we identified the difference with taxi daily operation pattern (weekday versus weekends, continuous time in one day, passengers in vehicle time, and taxi drivers’ operation frequency; in the space level, we explored the taxi driver’s searching pattern, including searching activity space distribution and the relationship between the pick-up locations and the drop-off locations. This research can be helpful for urban taxi drivers’ operation and behavior pattern identification, as well as the contribution to the geographical activity space analysis.

  3. System dynamics model of taxi management in metropolises: Economic and environmental implications for Beijing.

    Science.gov (United States)

    Wang, Hao; Zhang, Kai; Chen, Junhua; Wang, Zhifeng; Li, Guijun; Yang, Yuqi

    2018-05-01

    Taxis are an important component of urban passenger transport. Research on the daily dispatching of taxis and the utility of governmental management is important for the improvement of passenger travel, taxi driver income and environmental impacts. However, urban taxi management is a complex and dynamic system that is affected by many factors, and positive/negative feedback relationships and nonlinear interactions exist between each subsystem and variable. Therefore, conventional research methods can hardly depict its characteristics comprehensively. To bridge this gap, this paper develops a system dynamics model of urban taxi management, in which the empty-loaded rate and total demand are selected as key factors affecting taxi dispatching, and the impacts of taxi fares on driver income and travel demand are taken into account. After the validation of the model, taxi operations data derived from a prior analysis of origin-destination data of Beijing taxis are used as input for the model to simulate the taxi market in Beijing. Finally, economic and environmental implications are provided for the government to optimise policies on taxi management. Copyright © 2018 Elsevier Ltd. All rights reserved.

  4. Characterizing urban structure using taxi GPS data

    NARCIS (Netherlands)

    Zheng, Zhong; Zhou, Suhong; Rasouli, S.; Timmermans, H.J.P.

    2014-01-01

    Scholars have explored urban structure from many perspectives. Developments in ICT have made it possible to discover spatial patterns in activities using big data. The identified patterns allow us to better understand urban structure. This chapter reports the collection of taxi GPS records for a

  5. Examining the Interaction of Taxi and Subway Ridership for Sustainable Urbanization

    Directory of Open Access Journals (Sweden)

    Miaoyi Li

    2017-02-01

    Full Text Available A transit ridership study is an essential part of sustainability, and can provide a deep understanding of people’s travel patterns for efficient transportation development and urbanization. However, there is a lack of empirical studies comparing subway and taxi services, and their interactions within a city, that is to say, the interdependent transportation networks. Incorporating new data, this study aims to examine the spatial variation of urban taxi ridership due to the impacts of a new subway line operation opened in 2014 in Wuxi, China. We examine the spatial patterns and interactions of ridership in Wuxi by integrating taxi trajectory from GPS data and subway data from continuously collected fare transactions. The results indicated that the demand for taxi and subway usage is quite elastic with respect to both location and time, and the new subway’s opening had more influence on areas adjacent to subway stations and urban center-suburban travel. Furthermore, increases in travel time and distance would increase the demand for subway, while taxi trips largely represented movements for those locations that the subway could not reach. This paper betters the understanding of travel patterns through large volumes of transportation data for sustainable urbanization policy design.

  6. A Study on Optimal Resource Allocation of Taxis

    Directory of Open Access Journals (Sweden)

    Lv Xiao Peng

    2016-01-01

    Full Text Available As taxis play an increasingly important role in urban traffic system, the research on the supply and demand of taxis and the design of an optimal model of taxis supply has an importantly practical significance. In this paper, we used the traffic bureau data of Guangzhou, and determined the rate of empty driving as the index to establish the model. Nonlinear programming method was uesd to establish the optimal model of taxis quantity to meet the maximum income and maximum passenger satisfaction. Finally we got the optimal number of taxis was 37537.59

  7. Visual exploration of big spatio-temporal urban data: a study of New York City taxi trips.

    Science.gov (United States)

    Ferreira, Nivan; Poco, Jorge; Vo, Huy T; Freire, Juliana; Silva, Cláudio T

    2013-12-01

    As increasing volumes of urban data are captured and become available, new opportunities arise for data-driven analysis that can lead to improvements in the lives of citizens through evidence-based decision making and policies. In this paper, we focus on a particularly important urban data set: taxi trips. Taxis are valuable sensors and information associated with taxi trips can provide unprecedented insight into many different aspects of city life, from economic activity and human behavior to mobility patterns. But analyzing these data presents many challenges. The data are complex, containing geographical and temporal components in addition to multiple variables associated with each trip. Consequently, it is hard to specify exploratory queries and to perform comparative analyses (e.g., compare different regions over time). This problem is compounded due to the size of the data-there are on average 500,000 taxi trips each day in NYC. We propose a new model that allows users to visually query taxi trips. Besides standard analytics queries, the model supports origin-destination queries that enable the study of mobility across the city. We show that this model is able to express a wide range of spatio-temporal queries, and it is also flexible in that not only can queries be composed but also different aggregations and visual representations can be applied, allowing users to explore and compare results. We have built a scalable system that implements this model which supports interactive response times; makes use of an adaptive level-of-detail rendering strategy to generate clutter-free visualization for large results; and shows hidden details to the users in a summary through the use of overlay heat maps. We present a series of case studies motivated by traffic engineers and economists that show how our model and system enable domain experts to perform tasks that were previously unattainable for them.

  8. Modeling taxi driver anticipatory behavior

    NARCIS (Netherlands)

    Zheng, Zhong; Rasouli, S.; Timmermans, H.J.P.

    2018-01-01

    As part of a wider behavioral agent-based model that simulates taxi drivers’ dynamic passenger-finding behavior under uncertainty, we present a model of strategic behavior of taxi drivers in anticipation of substantial time varying demand at locations such as airports and major train stations. The

  9. TrajGraph: A Graph-Based Visual Analytics Approach to Studying Urban Network Centralities Using Taxi Trajectory Data.

    Science.gov (United States)

    Huang, Xiaoke; Zhao, Ye; Yang, Jing; Zhang, Chong; Ma, Chao; Ye, Xinyue

    2016-01-01

    We propose TrajGraph, a new visual analytics method, for studying urban mobility patterns by integrating graph modeling and visual analysis with taxi trajectory data. A special graph is created to store and manifest real traffic information recorded by taxi trajectories over city streets. It conveys urban transportation dynamics which can be discovered by applying graph analysis algorithms. To support interactive, multiscale visual analytics, a graph partitioning algorithm is applied to create region-level graphs which have smaller size than the original street-level graph. Graph centralities, including Pagerank and betweenness, are computed to characterize the time-varying importance of different urban regions. The centralities are visualized by three coordinated views including a node-link graph view, a map view and a temporal information view. Users can interactively examine the importance of streets to discover and assess city traffic patterns. We have implemented a fully working prototype of this approach and evaluated it using massive taxi trajectories of Shenzhen, China. TrajGraph's capability in revealing the importance of city streets was evaluated by comparing the calculated centralities with the subjective evaluations from a group of drivers in Shenzhen. Feedback from a domain expert was collected. The effectiveness of the visual interface was evaluated through a formal user study. We also present several examples and a case study to demonstrate the usefulness of TrajGraph in urban transportation analysis.

  10. Detecting Traffic Anomalies in Urban Areas Using Taxi GPS Data

    Directory of Open Access Journals (Sweden)

    Weiming Kuang

    2015-01-01

    Full Text Available Large-scale GPS data contain hidden information and provide us with the opportunity to discover knowledge that may be useful for transportation systems using advanced data mining techniques. In major metropolitan cities, many taxicabs are equipped with GPS devices. Because taxies operate continuously for nearly 24 hours per day, they can be used as reliable sensors for the perceived traffic state. In this paper, the entire city was divided into subregions by roads, and taxi GPS data were transformed into traffic flow data to build a traffic flow matrix. In addition, a highly efficient anomaly detection method was proposed based on wavelet transform and PCA (principal component analysis for detecting anomalous traffic events in urban regions. The traffic anomaly is considered to occur in a subregion when the values of the corresponding indicators deviate significantly from the expected values. This method was evaluated using a GPS dataset that was generated by more than 15,000 taxies over a period of half a year in Harbin, China. The results show that this detection method is effective and efficient.

  11. Taxi trips distribution modeling based on Entropy-Maximizing theory: A case study in Harbin city-China

    Science.gov (United States)

    Tang, Jinjun; Zhang, Shen; Chen, Xinqiang; Liu, Fang; Zou, Yajie

    2018-03-01

    Understanding Origin-Destination distribution of taxi trips is very important for improving effects of transportation planning and enhancing quality of taxi services. This study proposes a new method based on Entropy-Maximizing theory to model OD distribution in Harbin city using large-scale taxi GPS trajectories. Firstly, a K-means clustering method is utilized to partition raw pick-up and drop-off location into different zones, and trips are assumed to start from and end at zone centers. A generalized cost function is further defined by considering travel distance, time and fee between each OD pair. GPS data collected from more than 1000 taxis at an interval of 30 s during one month are divided into two parts: data from first twenty days is treated as training dataset and last ten days is taken as testing dataset. The training dataset is used to calibrate model while testing dataset is used to validate model. Furthermore, three indicators, mean absolute error (MAE), root mean square error (RMSE) and mean percentage absolute error (MPAE), are applied to evaluate training and testing performance of Entropy-Maximizing model versus Gravity model. The results demonstrate Entropy-Maximizing model is superior to Gravity model. Findings of the study are used to validate the feasibility of OD distribution from taxi GPS data in urban system.

  12. Exposure of bus and taxi drivers to urban air pollutants as measured by DNA and protein adducts

    DEFF Research Database (Denmark)

    Hemminki, K.; Zhang, L.F.; Krüger, J.

    1994-01-01

    Urinary 1-hydroxypyrene, lymphocyte DNA adducts, serum protein-bound PAH and hemoglobin-bound alkene adducts were analysed from 4 groups of non-smoking men: urban and suburban bus drivers, taxi drivers and suburban controls. The only differences between the groups were in DNA adducts between...... suburban bus drivers and controls, and in DNA adduct and plasma protein PAH-adducts between taxi drivers and controls....

  13. Agent-Based Modeling of Taxi Behavior Simulation with Probe Vehicle Data

    Directory of Open Access Journals (Sweden)

    Saurav Ranjit

    2018-05-01

    Full Text Available Taxi behavior is a spatial–temporal dynamic process involving discrete time dependent events, such as customer pick-up, customer drop-off, cruising, and parking. Simulation models, which are a simplification of a real-world system, can help understand the effects of change of such dynamic behavior. In this paper, agent-based modeling and simulation is proposed, that describes the dynamic action of an agent, i.e., taxi, governed by behavior rules and properties, which emulate the taxi behavior. Taxi behavior simulations are fundamentally done for optimizing the service level for both taxi drivers as well as passengers. Moreover, simulation techniques, as such, could be applied to another field of application as well, where obtaining real raw data are somewhat difficult due to privacy issues, such as human mobility data or call detail record data. This paper describes the development of an agent-based simulation model which is based on multiple input parameters (taxi stay point cluster; trip information (origin and destination; taxi demand information; free taxi movement; and network travel time that were derived from taxi probe GPS data. As such, agent’s parameters were mapped into grid network, and the road network, for which the grid network was used as a base for query/search/retrieval of taxi agent’s parameters, while the actual movement of taxi agents was on the road network with routing and interpolation. The results obtained from the simulated taxi agent data and real taxi data showed a significant level of similarity of different taxi behavior, such as trip generation; trip time; trip distance as well as trip occupancy, based on its distribution. As for efficient data handling, a distributed computing platform for large-scale data was used for extracting taxi agent parameter from the probe data by utilizing both spatial and non-spatial indexing technique.

  14. Comparison of Taxi Time Prediction Performance Using Different Taxi Speed Decision Trees

    Science.gov (United States)

    Lee, Hanbong

    2017-01-01

    In the STBO modeler and tactical surface scheduler for ATD-2 project, taxi speed decision trees are used to calculate the unimpeded taxi times of flights taxiing on the airport surface. The initial taxi speed values in these decision trees did not show good prediction accuracy of taxi times. Using the more recent, reliable surveillance data, new taxi speed values in ramp area and movement area were computed. Before integrating these values into the STBO system, we performed test runs using live data from Charlotte airport, with different taxi speed settings: 1) initial taxi speed values and 2) new ones. Taxi time prediction performance was evaluated by comparing various metrics. The results show that the new taxi speed decision trees can calculate the unimpeded taxi-out times more accurately.

  15. Factors associated with drug use among male motorbike taxi drivers in urban Vietnam.

    Science.gov (United States)

    Nguyen, Huy Van; Vu, Thinh Toan; Pham, Ha Nguyen

    2014-08-01

    A cross-sectional study was conducted on a sample of 291 male motorbike taxi drivers (MMTDs) recruited through social mapping technique in Hanoi, Vietnam, for face-to-face interviews to examine factors associated with drug use among MMTDs using Information-Motivation-Behavioral skills (IMB) model. Among 291 MMTDs, 17.18% reported drug use sometime in their lives, 96% of whom were drug injectors. Being depressed, being originally borne in urban cities, currently residing in rural areas, having a longer time living apart from their wives/lovers, using alcohol, following Buddhism, and reporting lower motivation of HIV prevention predict significantly higher odds of uptaking drugs.

  16. Optimizing Cruising Routes for Taxi Drivers Using a Spatio-Temporal Trajectory Model

    Directory of Open Access Journals (Sweden)

    Liang Wu

    2017-11-01

    Full Text Available Much of the taxi route-planning literature has focused on driver strategies for finding passengers and determining the hot spot pick-up locations using historical global positioning system (GPS trajectories of taxis based on driver experience, distance from the passenger drop-off location to the next passenger pick-up location and the waiting times at recommended locations for the next passenger. The present work, however, considers the average taxi travel speed mined from historical taxi GPS trajectory data and the allocation of cruising routes to more than one taxi driver in a small-scale region to neighboring pick-up locations. A spatio-temporal trajectory model with load balancing allocations is presented to not only explore pick-up/drop-off information but also provide taxi drivers with cruising routes to the recommended pick-up locations. In simulation experiments, our study shows that taxi drivers using cruising routes recommended by our spatio-temporal trajectory model can significantly reduce the average waiting time and travel less distance to quickly find their next passengers, and the load balancing strategy significantly alleviates road loads. These objective measures can help us better understand spatio-temporal traffic patterns and guide taxi navigation.

  17. Fuel cell drive for a taxi; Brennstoffzellen-Antrieb fuer ein Elektro-Taxi

    Energy Technology Data Exchange (ETDEWEB)

    Barker, Phil; Rosario, Leon; Sharp, Jon; Pouzet, Axel [Lotus Engineering, Norfolk (United Kingdom)

    2011-11-15

    Together with some partners Lotus Engineering has developed a fuel cell drive for a taxi. The prototype uses a Lithium Polymer battery pack as the peak power source and is analysed as an alternative for diesel drives in urban areas with stringent emission regulations. (orig.)

  18. Optimization of the revenue of the New York city taxi service using Markov Decision Processes

    NARCIS (Netherlands)

    Li, P.; Bhulai, Sandjai; van Essen, J.T.; Bhulai, Sandjai; Kardaras, Dimitris

    2017-01-01

    Taxis are an essential component of the transportation system in most urban centers. The ability to optimize the efficiency of routing represents an opportunity to increase revenues for taxi drivers. The vacant taxis cruising on the roads are not only wasting fuel consumption, the time of a taxi

  19. The share-a-ride problem : people and parcels sharing taxis

    NARCIS (Netherlands)

    Li, B.; Krushynskyi, D.; Reijers, H.A.; van Woensel, T.

    2014-01-01

    New city logistics approaches are needed to ensure efficient urban mobility for both people and goods. Usually, these are handled independently in dedicated networks. This paper considers conceptual and mathematical models in which people and parcels are handled in an integrated way by the same taxi

  20. Using an innovative price model to leverage the business model – The case of price model innovation in the largest Swedish taxi company

    Directory of Open Access Journals (Sweden)

    Carl-Johan Petri

    2014-08-01

    Full Text Available Purpose: The purpose of the paper is to describe how the biggest Swedish taxi company (Taxi Kurir developed an innovative price model to leverage the business model. Design/methodology/approach : The empirical data in the article describe Taxi Kurir’s development of a new price model. Data about the Swedish taxi market and about Taxi Kurir has been compiled though interviews and document studies. Detailed information about the background, development and implementation of Taxi Kurir’s new price model has been captured through interviews with representatives from Taxi Kurir. Findings : Based on both the empirical example, and other investigations, we have found that a company can create substantial changes in their price model, by just changing some of its basic characteristics. A well designed price model can contribute to leveraging the intentions of the business model. Practical implications : Most academic and practical texts about business models consider pricing to be an important component. However, they typically do not refer to the specifics of the price- or revenue models. According to the literature review in this paper, and the empirical findings, the configuration of a company’s price model should be aligned with its business model. This will contribute to leveraging the business model. Originality/value: The Swedish taxi market is one of the most deregulated in the world. Differently from most other countries, any individual or company can start and operate a taxi business. This case offers a unique description on how the biggest company in the market responded to the competition by introducing a fundamentally new price model, by making a small change in one of the dimensions in their existing price model.

  1. Investigation of in-cabin volatile organic compounds (VOCs) in taxis; influence of vehicle's age, model, fuel, and refueling.

    Science.gov (United States)

    Bakhtiari, Reza; Hadei, Mostafa; Hopke, Philip K; Shahsavani, Abbas; Rastkari, Noushin; Kermani, Majid; Yarahmadi, Maryam; Ghaderpoori, Afshin

    2018-06-01

    The air pollutant species and concentrations in taxis' cabins can present significant health impacts on health. This study measured the concentrations of benzene, toluene, ethylbenzene, xylene (BTEX), formaldehyde, and acetaldehyde in the cabins of four different taxi models. The effects of taxi's age, fuel type, and refueling were investigated. Four taxi models in 3 age groups were fueled with 3 different fuels (gas, compressed natural gas (CNG), and liquefied petroleum gas (LPG)), and the concentrations of 6 air pollutants were measured in the taxi cabins before and after refueling. BTEX, formaldehyde, and acetaldehyde sampling were actively sampled using NIOSH methods 1501, 2541, and 2538, respectively. The average BTEX concentrations for all taxi models were below guideline values. The average concentrations (±SD) of formaldehyde in Model 1 to Model 4 taxis were 889 (±356), 806 (±323), 1144 (±240), and 934 (±167) ppbv, respectively. Acetaldehyde average concentrations (±SD) in Model 1 to Model 4 taxis were 410 (±223), 441 (±241), 443 (±210), and 482 (±91) ppbv, respectively. Refueling increased the in-vehicle concentrations of pollutants primarily the CNG and LPG fuels. BTEX concentrations in all taxi models were significantly higher for gasoline. Taxi age inversely affected formaldehyde and acetaldehyde. In conclusion, it seems that refueling process and substitution of gasoline with CNG and LPG can be considered as solutions to improve in-vehicle air concentrations for taxis. Copyright © 2018. Published by Elsevier Ltd.

  2. Methods for determining unimpeded aircraft taxiing time and evaluating airport taxiing performance

    Directory of Open Access Journals (Sweden)

    Yu Zhang

    2017-04-01

    Full Text Available The objective of this study is to improve the methods of determining unimpeded (nominal taxiing time, which is the reference time used for estimating taxiing delay, a widely accepted performance indicator of airport surface movement. After reviewing existing methods used widely by different air navigation service providers (ANSP, new methods relying on computer software and statistical tools, and econometrics regression models are proposed. Regression models are highly recommended because they require less detailed data and can serve the needs of general performance analysis of airport surface operations. The proposed econometrics model outperforms existing ones by introducing more explanatory variables, especially taking aircraft passing and over-passing into the considering of queue length calculation and including runway configuration, ground delay program, and weather factors. The length of the aircraft queue in the taxiway system and the interaction between queues are major contributors to long taxi-out times. The proposed method provides a consistent and more accurate method of calculating taxiing delay and it can be used for ATM-related performance analysis and international comparison.

  3. Three-wheeled scooter taxi: A safety analysis

    Indian Academy of Sciences (India)

    Three-wheel scooter taxis (TSR) form an essential part of public transport for the urban ... These low cost vehicles will remain a major mode of travel in the South Asian region ... commercial codes can be avoided for computational efficiency.

  4. Modeling of the service taxi

    Directory of Open Access Journals (Sweden)

    R. M. Bezborodnikova

    2016-01-01

    Full Text Available Modeling and optimization business processes are ongoing challenges of modernity. Based on the study of business processes to anticipate and avoid many problems in the work of companies linked primarily with an increased level of costs, the low quality of the performed works and manufactured products, excessive run time functions. Application of simulation tool for business processes allows at the stage of planning to assess various indicators of the effectiveness of processes to identify the best sequence of functions, determine resource costs to calculate personnel workload, thereby facilitating timely adoption of the correct administrative decisions. The article deals with the modeling of the business process “Order processing” taxi service Heat the city of Orenburg. Based on the methodology of modeling Business Process Model and Notation (BPMN built functional diagram of the business process (with freely distributed software product Bizagi Modeler, given the resources used, the costs of their use, built calendar schedules. Next, the operation was carried out simulations with different process input data: the number of incoming applications, the number of controllers and advertising budget. It is shown that the efficiency of the business process will contribute to the increase in the total number of dispatchers up to 6 people, as well as increasing advertising costs doubled. As a result of the decisions taken is expected to increase the net income of the company to 76 794 RUR and the average salary of the staff (in particular taxi drivers to 42 281 RUR, dispatchers and 22 799 RUR, as well as reducing the duration of processing a single order up to 31 minutes.

  5. Research on the Coordinated Design of Bus and Taxi Station

    Directory of Open Access Journals (Sweden)

    Jiangfeng Xi

    2015-01-01

    Full Text Available Rises in the number of transit buses, bus routes, and overall traffic volume in China’s cities, coupled with interference from other transport modes, such as taxis loading and unloading passengers nearby, have led to increasing traffic delays at bus stops, which is considered one of the factors degrading service levels and traffic operations on urban roadways. This paper studies traffic characteristics at bus stops, investigates variations in delay from different types or designs of bus stops, and analyzes the impact of it on traffic capacity, the purpose of which is to propose a solution to predicting the feasibility of an integrated design of bus stops and taxi stands with the help of mathematical models and based on the objectives of optimal traffic operations and passenger transfer.

  6. Taxis and crowd-taxis: sharing as a private activity and public concern

    Directory of Open Access Journals (Sweden)

    Merethe Dotterud Leiren

    2016-06-01

    Full Text Available The sharing economy has generated interest among economists for its customer focus and potential to enhance competition. However, it has also caused uproar in industries which have felt competitive pressure, for example among the established stakeholders in the taxi industry. While regulations currently impose considerable costs on the taxi industry, they do not cover virtual transport innovations such as Uber. The lack of a level playing field between taxis and such ‘crowd-taxis’ has generated media attention and conflict. Taxi owners worry about decreasing revenues and taxi drivers about poor working conditions. Other concerns are related to poor transport preparedness, accessibility issues, quality assurance and tax evasion. Despite considerable media attention, there has so far been a lack of scholarly literature addressing the consequences of the sharing economy in the transport sector. Focusing on the Norwegian taxi market, we argue that crowd-taxis will likely produce a range of unanticipated effects, necessitating regulation. For example, crowd-taxis may contribute to a loss of transport preparedness in rural areas. The findings are based on first and secondary data and 19 interviews.

  7. Social optimal shifts and fares of taxi services

    Energy Technology Data Exchange (ETDEWEB)

    Salanova Grau, J.M.; Estrada Romeu, M.

    2016-07-01

    This paper presents a mathematical model for supporting the decision and policy making related to the optimal determination of shifts and fares of taxi services in a major city. The model is based on the system’s generalized cost function and uses continuous approximations and geometric probabilities for estimating the key performance indicators of the taxi market, which are waiting and access time for the customers (in-vehicle travel time does not depend on the offer side) and benefits for the drivers. The model is based on an econometric model with the inclusion of an elastic demand, which allows the estimation of the optimal values for the two decision variables of the problem: fare structure and the taxi fleet size. The model also accounts for a full-day time period instead of the one-hour time frame models used in most of the taxi models, which allows for providing insights on the daily duration and distribution of the shifts that should be defined by the policy makers. (Author)

  8. Inferring Passenger Denial Behavior of Taxi Drivers from Large-Scale Taxi Traces.

    Directory of Open Access Journals (Sweden)

    Sihai Zhang

    Full Text Available How to understand individual human actions is a fundamental question to modern science, which drives and incurs many social, technological, racial, religious and economic phenomena. Human dynamics tries to reveal the temporal pattern and internal mechanism of human actions in letter or electronic communications, from the perspective of continuous interactions among friends or acquaintances. For interactions between stranger to stranger, taxi industry provide fruitful phenomina and evidence to investigate the action decisions. In fact, one striking disturbing events commonly reported in taxi industry is passenger refusing or denial, whose reasons vary, including skin color, blind passenger, being a foreigner or too close destination, religion reasons and anti specific nationality, so that complaints about taxi passenger refusing have to be concerned and processed carefully by local governments. But more universal factors for this phenomena are of great significance, which might be fulfilled by big data research to obtain novel insights in this question. In this paper, we demonstrate the big data analytics application in revealing novel insights from massive taxi trace data, which, for the first time, validates the passengers denial in taxi industry and estimates the denial ratio in Beijing city. We first quantify the income differentiation facts among taxi drivers. Then we find out that choosing the drop-off places also contributes to the high income for taxi drivers, compared to the previous explanation of mobility intelligence. Moreover, we propose the pick-up, drop-off and grid diversity concepts and related diversity analysis suggest that, high income taxi drivers will deny passengers in some situations, so as to choose the passengers' destination they prefer. Finally we design an estimation method for denial ratio and infer that high income taxi drivers will deny passengers with 8.52% likelihood in Beijing. Our work exhibits the power of big

  9. Toronto hybrid taxi pilot

    International Nuclear Information System (INIS)

    Stevens, M.; Marans, B.

    2009-10-01

    This paper provided details of a hybrid taxi pilot program conducted to compare the on-road performance of Toyota Camry hybrid vehicles against conventional vehicles over a 1-year period in order to determine the business case and air emission reductions associated with the use of hybrid taxi cabs. Over 750,000 km worth of fuel consumption was captured from 10 Toyota Camry hybrids, a Toyota Prius, and 5 non-hybrid Camry vehicles over an 18-month period. The average real world fuel consumption for the taxis demonstrated that the Toyota Prius has the lowest cost of ownership, while the non-hybrid Camry has the highest cost of ownership. Carbon dioxide (CO 2 ) reductions associated with the 10 Camry hybrid taxis were calculated at 236 tonnes over a 7-year taxi service life. Results suggested that the conversion of Toronto's 5680 taxis would yield annual CO 2 emission reductions of over 19,000 tonnes. All hybrid purchasers identified themselves as highly likely to purchase a hybrid again. 5 tabs., 9 figs.

  10. Toronto hybrid taxi pilot

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, M. [CrossChasm Technologies, Cambridge, ON (Canada); Marans, B. [Toronto Atmospheric Fund, ON (Canada)

    2009-10-15

    This paper provided details of a hybrid taxi pilot program conducted to compare the on-road performance of Toyota Camry hybrid vehicles against conventional vehicles over a 1-year period in order to determine the business case and air emission reductions associated with the use of hybrid taxi cabs. Over 750,000 km worth of fuel consumption was captured from 10 Toyota Camry hybrids, a Toyota Prius, and 5 non-hybrid Camry vehicles over an 18-month period. The average real world fuel consumption for the taxis demonstrated that the Toyota Prius has the lowest cost of ownership, while the non-hybrid Camry has the highest cost of ownership. Carbon dioxide (CO{sub 2}) reductions associated with the 10 Camry hybrid taxis were calculated at 236 tonnes over a 7-year taxi service life. Results suggested that the conversion of Toronto's 5680 taxis would yield annual CO{sub 2} emission reductions of over 19,000 tonnes. All hybrid purchasers identified themselves as highly likely to purchase a hybrid again. 5 tabs., 9 figs.

  11. Collective human mobility pattern from taxi trips in urban area

    KAUST Repository

    Peng, Chengbin

    2012-04-18

    We analyze the passengers\\' traffic pattern for 1.58 million taxi trips of Shanghai, China. By employing the non-negative matrix factorization and optimization methods, we find that, people travel on workdays mainly for three purposes: commuting between home and workplace, traveling from workplace to workplace, and others such as leisure activities. Therefore, traffic flow in one area or between any pair of locations can be approximated by a linear combination of three basis flows, corresponding to the three purposes respectively. We name the coefficients in the linear combination as traffic powers, each of which indicates the strength of each basis flow. The traffic powers on different days are typically different even for the same location, due to the uncertainty of the human motion. Therefore, we provide a probability distribution function for the relative deviation of the traffic power. This distribution function is in terms of a series of functions for normalized binomial distributions. It can be well explained by statistical theories and is verified by empirical data. These findings are applicable in predicting the road traffic, tracing the traffic pattern and diagnosing the traffic related abnormal events. These results can also be used to infer land uses of urban area quite parsimoniously. 2012 Peng et al.

  12. Talent in the taxi: a model system for exploring expertise.

    Science.gov (United States)

    Woollett, Katherine; Spiers, Hugo J; Maguire, Eleanor A

    2009-05-27

    While there is widespread interest in and admiration of individuals with exceptional talents, surprisingly little is known about the cognitive and neural mechanisms underpinning talent, and indeed how talent relates to expertise. Because many talents are first identified and nurtured in childhood, it can be difficult to determine whether talent is innate, can be acquired through extensive practice or can only be acquired in the presence of the developing brain. We sought to address some of these issues by studying healthy adults who acquired expertise in adulthood. We focused on the domain of memory and used licensed London taxi drivers as a model system. Taxi drivers have to learn the layout of 25,000 streets in London and the locations of thousands of places of interest, and pass stringent examinations in order to obtain an operating licence. Using neuropsychological assessment and structural and functional magnetic resonance imaging, we addressed a range of key questions: in the context of a fully developed brain and an average IQ, can people acquire expertise to an exceptional level; what are the neural signatures, both structural and functional, associated with the use of expertise; does expertise change the brain compared with unskilled control participants; does it confer any cognitive advantages, and similarly, does it come at a cost to other functions? By studying retired taxi drivers, we also consider what happens to their brains and behaviour when experts stop using their skill. Finally, we discuss how the expertise of taxi drivers might relate to the issue of talent and innate abilities. We suggest that exploring talent and expertise in this manner could have implications for education, rehabilitation of patients with cognitive impairments, understanding individual differences and possibly conditions such as autism where exceptional abilities can be a feature.

  13. Turing-Hopf bifurcations in a predator-prey model with herd behavior, quadratic mortality and prey-taxis

    Science.gov (United States)

    Liu, Xia; Zhang, Tonghua; Meng, Xinzhu; Zhang, Tongqian

    2018-04-01

    In this paper, we propose a predator-prey model with herd behavior and prey-taxis. Then, we analyze the stability and bifurcation of the positive equilibrium of the model subject to the homogeneous Neumann boundary condition. By using an abstract bifurcation theory and taking prey-tactic sensitivity coefficient as the bifurcation parameter, we obtain a branch of stable nonconstant solutions bifurcating from the positive equilibrium. Our results show that prey-taxis can yield the occurrence of spatial patterns.

  14. Scaling Law of Urban Ride Sharing

    Science.gov (United States)

    Tachet, R.; Sagarra, O.; Santi, P.; Resta, G.; Szell, M.; Strogatz, S. H.; Ratti, C.

    2017-03-01

    Sharing rides could drastically improve the efficiency of car and taxi transportation. Unleashing such potential, however, requires understanding how urban parameters affect the fraction of individual trips that can be shared, a quantity that we call shareability. Using data on millions of taxi trips in New York City, San Francisco, Singapore, and Vienna, we compute the shareability curves for each city, and find that a natural rescaling collapses them onto a single, universal curve. We explain this scaling law theoretically with a simple model that predicts the potential for ride sharing in any city, using a few basic urban quantities and no adjustable parameters. Accurate extrapolations of this type will help planners, transportation companies, and society at large to shape a sustainable path for urban growth.

  15. Grid Mapping for Spatial Pattern Analyses of Recurrent Urban Traffic Congestion Based on Taxi GPS Sensing Data

    Directory of Open Access Journals (Sweden)

    Yang Liu

    2017-03-01

    Full Text Available Traffic congestion is one of the most serious problems that impact urban transportation efficiency, especially in big cities. Identifying traffic congestion locations and occurring patterns is a prerequisite for urban transportation managers in order to take proper countermeasures for mitigating traffic congestion. In this study, the historical GPS sensing data of about 12,000 taxi floating cars in Beijing were used for pattern analyses of recurrent traffic congestion based on the grid mapping method. Through the use of ArcGIS software, 2D and 3D maps of the road network congestion were generated for traffic congestion pattern visualization. The study results showed that three types of traffic congestion patterns were identified, namely: point type, stemming from insufficient capacities at the nodes of the road network; line type, caused by high traffic demand or bottleneck issues in the road segments; and region type, resulting from multiple high-demand expressways merging and connecting to each other. The study illustrated that the proposed method would be effective for discovering traffic congestion locations and patterns and helpful for decision makers to take corresponding traffic engineering countermeasures in order to relieve the urban traffic congestion issues.

  16. [Occupational risk factors and perceptions of air pollution by motorcycle taxi drivers in Cotonou, Benin].

    Science.gov (United States)

    Lawin, Hervé; Ayi Fanou, Lucie; Hinson, Vikkey; Tollo, Brice; Fayomi, Benjamin; Ouendo, Edgard-Marius

    Motorcycle taxis occupy a major place in urban transport. Motorcycle taxi drivers are exposed to occupational risk factors (ORF) including air pollution. The objective of this study was to evaluate these ORF among motorcycle taxi drivers and their perceptions of air pollution. This mixed study was conducted on motorcycle taxi drivers in Cotonou. The qualitative study was based on focus groups concerning 16 items from the Participatory Occupational Risk Screening Guide (DEPARIS) until saturation and after triangulation of data. The quantitative study consisted of administering a questionnaire addressing socioeconomic and demographic characteristics, cardiopulmonary diseases, and perception of air -pollution risk factors among 397 Cotonou motorcycle taxi drivers. Drivers perceived poor road conditions, effort and handling, and lack of social security as unsatisfactory ORF. Their mean age was 40.95 ± 8.75 years and 45.84% had primary -education. They had been working as motorcycle taxi drivers for an average of 134.95 ± 101.53 months with an average income of FCFA 3138 ± 1238. These occupational factors were significantly associated with cardiopulmonary disorders, observed in 63.2% of drivers. Less than 1/3 of drivers felt that air pollution affected their personal health. Motorcycle taxi drivers have a poor perception of ORF and the severity of exposure to air pollution in this occupation. There is a need to take action to promote the health of this population.

  17. Research on taxi software policy based on big data

    Directory of Open Access Journals (Sweden)

    Feng Daoming

    2017-01-01

    Full Text Available Through big data analysis, statistical analysis of a large number of factors affect the establishment of the rally car index set, By establishing a mathematical model to analyze the different space-time taxi resource “to match supply and demand” degree, combined with intelligent deployment to solve the “taxi difficult” this hot social issues. This article takes Shanghai as an example, the central park, Lu Xun park, century park three areas as the object of study. From the “sky drops fast travel intelligence platform” big data, Extracted passenger demand and the number of taxi Kongshi data. Then demand and supply of taxis to establish indicators matrix, get the degree of matching supply needs of the region. Then through the big data relevant policies of each taxi company. Using the method of cluster analysis, to find the decisive role of the three aspects of the factors, using principal component analysis, compare the advantages and disadvantages of the existing company’s programs. Finally, according to the above research to develop a reasonable taxi software related policies.

  18. Estimation of occupational and nonoccupational nitrogen dioxide exposure for Korean taxi drivers using a microenvironmental model

    International Nuclear Information System (INIS)

    Son, Busoon; Yang, Wonho; Breysse, Patrick; Chung, Taewoong; Lee, Youngshin

    2004-01-01

    Occupational and nonoccupational personal nitrogen dioxide (NO 2 ) exposures were measured using passive samplers for 31 taxi drivers in Asan and Chunan, Korea. Exposures were also estimated using a microenvironmental time-weighted average model based on indoor, outdoor and inside the taxi area measurements. Mean NO 2 indoor and outdoor concentrations inside and outside the taxi drivers' houses were 24.7±10.7 and 23.3±8.3 ppb, respectively, with a mean indoor to outdoor NO 2 ratio of 1.1. Mean personal NO 2 exposure of taxi drivers was 30.3±9.7 ppb. Personal NO 2 exposures for drivers were more strongly correlated with interior vehicle NO 2 levels (r=0.89) rather than indoor residential NO 2 levels (r=0.74) or outdoor NO 2 levels (r=0.71). The main source of NO 2 exposure for taxi drivers was considered to be occupational driving. Interestingly, the NO 2 exposures for drivers' using LPG-fueled vehicles (26.3±1.3 ppb) were significantly lower than those (38.1±1.3 ppb) using diesel-fueled vehicle (P 2 exposure with indoor and outdoor NO 2 levels of the residence, and interior vehicle NO 2 levels (P 2 levels because they drive diesel-using vehicles outdoors in Korea

  19. Mining Open Datasets for Transparency in Taxi Transport in Metropolitan Environments

    OpenAIRE

    Noulas, Anastasios; Salnikov, Vsevolod; Lambiotte, Renaud; Mascolo, Cecilia

    2015-01-01

    Uber has recently been introducing novel practices in urban taxi transport. Journey prices can change dynamically in almost real time and also vary geographically from one area to another in a city, a strategy known as surge pricing. In this paper, we explore the power of the new generation of open datasets towards understanding the impact of the new disruption technologies that emerge in the area of public transport. With our primary goal being a more transparent economic landscape for urban...

  20. Automation of Taxiing

    Directory of Open Access Journals (Sweden)

    Jaroslav Bursík

    2017-01-01

    Full Text Available The article focuses on the possibility of automation of taxiing, which is the part of a flight, which, under adverse weather conditions, greatly reduces the operational usability of an airport, and is the only part of a flight that has not been affected by automation, yet. Taxiing is currently handled manually by the pilot, who controls the airplane based on information from visual perception. The article primarily deals with possible ways of obtaining navigational information, and its automatic transfer to the controls. Analyzed wand assessed were currently available technologies such as computer vision, Light Detection and Ranging and Global Navigation Satellite System, which are useful for navigation and their general implementation into an airplane was designed. Obstacles to the implementation were identified, too. The result is a proposed combination of systems along with their installation into airplane’s systems so that it is possible to use the automated taxiing.

  1. A lightweight neighbor-info-based routing protocol for no-base-station taxi-call system.

    Science.gov (United States)

    Zhu, Xudong; Wang, Jinhang; Chen, Yunchao

    2014-01-01

    Since the quick topology change and short connection duration, the VANET has had unstable routing and wireless signal quality. This paper proposes a kind of lightweight routing protocol-LNIB for call system without base station, which is applicable to the urban taxis. LNIB maintains and predicts neighbor information dynamically, thus finding the reliable path between the source and the target. This paper describes the protocol in detail and evaluates the performance of this protocol by simulating under different nodes density and speed. The result of evaluation shows that the performance of LNIB is better than AODV which is a classic protocol in taxi-call scene.

  2. The application of algorithm in taxi security system

    Science.gov (United States)

    Luo, Chengyu

    2017-08-01

    With the booming of the society and economy today, Taxis and private cars have gradually become one of the most popular tools in transportation for their low price and convenience. However, because of the breakdown in the security system, a few accidents occurred due to the illegal taxi. The unreliable security management has attributed to the lack of trust in taxi companies and relevant regulatory authorities, which considered to be the reason why people are worried about it. Accordingly, we put forward a design for a taxi security system, making use of modern technology such as NFC, iBeacon, GPS combined with algorithms, automatically recognize the taxi we take, and reflecting basic information of taxi and driver on our mobile phone.

  3. On-road emission characteristics of CNG-fueled bi-fuel taxis

    Science.gov (United States)

    Yao, Zhiliang; Cao, Xinyue; Shen, Xianbao; Zhang, Yingzhi; Wang, Xintong; He, Kebin

    2014-09-01

    To alleviate air pollution and lessen the petroleum demand from the motor vehicle sector in China, natural gas vehicles (NGVs) have been rapidly developed over the last several years. However, the understanding of the real-world emissions of NGVs is very limited. In this study, the emissions from 20 compressed-natural-gas-fueled bi-fuel taxis were measured using a portable emission measurement system (PEMS) under actual driving conditions in Yichang, China. The emission characteristics of the tested vehicles were analyzed, revealing that the average CO2, CO, HC and NOx emissions from the tested compressed-natural-gas (CNG) taxis under urban driving conditions were 1.6, 4.0, 2.0 and 0.98 times those under highway road conditions, respectively. The CO, HC and NOx emissions from Euro 3 CNG vehicles were approximately 40%, 55% and 44% lower than those from Euro 2 vehicles, respectively. Compared with the values for light-duty gasoline vehicles reported in the literature, the CO2 and CO emissions from the tested CNG taxis were clearly lower; however, significant increases in the HC and NOx emissions were observed. Finally, we normalized the emissions under the actual driving cycles of the entire test route to the New European Driving Cycle (NEDC)-based emissions using a VSP modes method developed by North Carolina State University. The simulated NEDC-based CO emissions from the tested CNG taxis were better than the corresponding emissions standards, whereas the simulated NEDC-based HC and NOx emissions greatly exceeded the standards. Thus, more attention should be paid to the emissions from CNG vehicles. As for the CNG-fueled bi-fuel taxis currently in use, the department of environmental protection should strengthen their inspection and supervision to reduce the emissions from these vehicles. The results of this study will be helpful in understanding and controlling emissions from CNG-fueled bi-fuel vehicles in China.

  4. Cost, Energy, and Environmental Impact of Automated Electric Taxi Fleets in Manhattan.

    Science.gov (United States)

    Bauer, Gordon S; Greenblatt, Jeffery B; Gerke, Brian F

    2018-04-17

    Shared automated electric vehicles (SAEVs) hold great promise for improving transportation access in urban centers while drastically reducing transportation-related energy consumption and air pollution. Using taxi-trip data from New York City, we develop an agent-based model to predict the battery range and charging infrastructure requirements of a fleet of SAEVs operating on Manhattan Island. We also develop a model to estimate the cost and environmental impact of providing service and perform extensive sensitivity analysis to test the robustness of our predictions. We estimate that costs will be lowest with a battery range of 50-90 mi, with either 66 chargers per square mile, rated at 11 kW or 44 chargers per square mile, rated at 22 kW. We estimate that the cost of service provided by such an SAEV fleet will be $0.29-$0.61 per revenue mile, an order of magnitude lower than the cost of service of present-day Manhattan taxis and $0.05-$0.08/mi lower than that of an automated fleet composed of any currently available hybrid or internal combustion engine vehicle (ICEV). We estimate that such an SAEV fleet drawing power from the current NYC power grid would reduce GHG emissions by 73% and energy consumption by 58% compared to an automated fleet of ICEVs.

  5. Energy Taxis Is the Dominant Behavior in Azospirillum brasilense

    Science.gov (United States)

    Alexandre, Gladys; Greer, Suzanne E.; Zhulin, Igor B.

    2000-01-01

    Energy taxis encompasses aerotaxis, phototaxis, redox taxis, taxis to alternative electron acceptors, and chemotaxis to oxidizable substrates. The signal for this type of behavior is originated within the electron transport system. Energy taxis was demonstrated, as a part of an overall behavior, in several microbial species, but it did not appear as the dominant determinant in any of them. In this study, we show that most behavioral responses proceed through this mechanism in the alpha-proteobacterium Azospirillum brasilense. First, chemotaxis to most chemoeffectors typical of the azospirilla habitat was found to be metabolism dependent and required a functional electron transport system. Second, other energy-related responses, such as aerotaxis, redox taxis, and taxis to alternative electron acceptors, were found in A. brasilense. Finally, a mutant lacking a cytochrome c oxidase of the cbb3 type was affected in chemotaxis, redox taxis, and aerotaxis. Altogether, the results indicate that behavioral responses to most stimuli in A. brasilense are triggered by changes in the electron transport system. PMID:11029423

  6. Economic Analysis on Value Chain of Taxi Fleet with Battery-Swapping Mode Using Multiobjective Genetic Algorithm

    OpenAIRE

    Ning, Guobao; Zhen, Zijian; Wang, Peng; Li, Yang; Yin, Huaixian

    2012-01-01

    This paper presents an economic analysis model on value chain of taxi fleet with battery-swapping mode in a pilot city. In the model, economic benefits of charging-swapping station group, taxi company, and taxi driver in the region have been taken into consideration. Thus, the model is a multiobjective function and multiobjective genetic algorithm is used to solve this problem. According to the real data collected from the pilot city, the multiobjective genetic algorithm is tested as an effec...

  7. Taxi-Out Time Prediction for Departures at Charlotte Airport Using Machine Learning Techniques

    Science.gov (United States)

    Lee, Hanbong; Malik, Waqar; Jung, Yoon C.

    2016-01-01

    Predicting the taxi-out times of departures accurately is important for improving airport efficiency and takeoff time predictability. In this paper, we attempt to apply machine learning techniques to actual traffic data at Charlotte Douglas International Airport for taxi-out time prediction. To find the key factors affecting aircraft taxi times, surface surveillance data is first analyzed. From this data analysis, several variables, including terminal concourse, spot, runway, departure fix and weight class, are selected for taxi time prediction. Then, various machine learning methods such as linear regression, support vector machines, k-nearest neighbors, random forest, and neural networks model are applied to actual flight data. Different traffic flow and weather conditions at Charlotte airport are also taken into account for more accurate prediction. The taxi-out time prediction results show that linear regression and random forest techniques can provide the most accurate prediction in terms of root-mean-square errors. We also discuss the operational complexity and uncertainties that make it difficult to predict the taxi times accurately.

  8. Performance, poverty and urban development: Kigali’s motari and the spectacle city

    Directory of Open Access Journals (Sweden)

    William Rollason

    2013-09-01

    Full Text Available In this paper I explore tensions and conflicts over poverty reduction and urban development in Kigali, Rwanda’s capital in terms of theories of performativity. On one hand, motorcycle taxis offer large numbers of young men good livelihoods – reflecting the government of Rwanda’s stated commitment to poverty reduction, especially amongst youth; on the other, motorcycle taxi drivers suffer harassment at the hands of city authorities and police, who are keen to eradicate motorcycle taxis from the urban scene altogether. I interpret this tension as a conflict over the appropriate performance of development in the city; I argue that in pursuit of urban development, the city itself becomes an image, projected in order to attract the investment which will give body to the simulated spectacle that Kigali present. Conflicts between the city and motorcycle taxi drivers erupt because motorcycle taxis cannot perform to the aesthetic standards of the new Kigali. In conclusion, I suggest that the rendition of Kigali’s development as image has broader lessons for studies of development in general. Specifically, these conflicts expose the operation of images and their performance as political resources, conferring intelligibility and legitimacy in the spectacle of national development. Key words: Rwanda, poverty reduction, urban development, performativity

  9. Autonomous vehicles are cost-effective when used as taxis.

    Science.gov (United States)

    Freedman, Isaac G; Kim, Ellen; Muennig, Peter A

    2018-06-04

    Autonomous vehicles (AVs) will radically re-shape the health and well-being of people in the United States in good ways and bad. We set out to estimate a reasonable time-to-adoption using cost-effectivenessmodels to estimate the point at which AVs become reasonably safe and affordable for widespread adoption. We used Waymo data (previously, Google Self-Driving Car Project) and a microsimulation model to explore projected costs and safety issues today and five years from today to get a sense of the speed of consumer adoption were AVs brought to the market. The adoption of AVs for private use was associated with an ICER of 1,396,110/QALY gained today, a figure that would decline to 173,890/QALY gained 5-years in the future. However, AV taxis are both less expensive and potentially already safer than human-piloted taxis. While AVs are not unlikely to be used a family vehicles any time soon, it would make economic sense to adopt them as taxis today. Legislation enhancing the benefits while mitigating the potential harmful health impacts of AV taxis is needed with some urgency.

  10. Research on Taxi Driver Strategy Game Evolution with Carpooling Detour

    Directory of Open Access Journals (Sweden)

    Wei Zhang

    2018-01-01

    Full Text Available For the problem of taxi carpooling detour, this paper studies driver strategy choice with carpooling detour. The model of taxi driver strategy evolution with carpooling detour is built based on prospect theory and evolution game theory. Driver stable strategies are analyzed under the conditions of complaint mechanism and absence of mechanism, respectively. The results show that passenger’s complaint mechanism can effectively decrease the phenomenon of driver refusing passengers with carpooling detour. When probability of passenger complaint reaches a certain level, the stable strategy of driver is to take carpooling detour passengers. Meanwhile, limiting detour distance and easing traffic congestion can decrease the possibility of refusing passengers. These conclusions have a certain guiding significance to formulating taxi policy.

  11. Labeling Residential Community Characteristics from Collective Activity Patterns Using Taxi Trip Data

    Science.gov (United States)

    Zhou, Y.; Fang, Z.

    2017-09-01

    There existing a significant social and spatial differentiation in the residential communities in urban city. People live in different places have different socioeconomic background, resulting in various geographically activity patterns. This paper aims to label the characteristics of residential communities in a city using collective activity patterns derived from taxi trip data. Specifically, we first present a method to allocate the O/D (Origin/Destination) points of taxi trips to the land use parcels where the activities taken place in. Then several indices are employed to describe the collective activity patterns, including both activity intensity, travel distance, travel time, and activity space of residents by taking account of the geographical distribution of all O/Ds of the taxi trip related to that residential community. Followed by that, an agglomerative hierarchical clustering algorithm is introduced to cluster the residential communities with similar activity patterns. In the case study of Wuhan, the residential communities are clearly divided into eight clusters, which could be labelled as ordinary communities, privileged communities, old isolated communities, suburban communities, and so on. In this paper, we provide a new perspective to label the land use under same type from people's mobility patterns with the support of big trajectory data.

  12. A COMMUNITY STUDY OF TAXI VIOLENCE AND DISTRESS ...

    African Journals Online (AJOL)

    Setting & Subjects: Five hundred and four Xhosa speaking youth aged 9-20 years, from 5 primary schools in Khayelitsha; 396 attending 4 schools in close proximity to ... Those who had been in a taxi that was shot at, those who had been at a taxi rank when people were shot, and those who had seen taxi men shooting, had ...

  13. Taxi and limousine industry in Canada

    International Nuclear Information System (INIS)

    Monteiro, J.; Civettini, S.

    2007-01-01

    Taxi and limousine service plays an important role in the movement of people within a city. In 2004, the total revenue in this industry in Canada was $1.305 billion, and an estimated 35,339 carriers served the industry. In Canada, economic and safety regulations of taxi supply were imposed in most cities during the 1930s and 1940s and continue to this date. Although the industry is regulated, the competition law also applies. The appropriateness of these regulations continues to be challenged and regulatory reforms in the major cities in Canada have concentrated their efforts on increasing the rate of services, improving the quality of vehicles and enhancing the training of taxi drivers. Indicators for the 1999-2004 period reveal that the taxi and limousine industry in Canada did not perform very well. Revenue increased by only 1.7 per cent per year and margins deteriorated by -1.78 per cent together with the operating ratio. The purpose of this paper was to examine the taxi and limousine industry in Canada. First, the structure of the industry in Canada was examined followed by a review of the economic regulation of the industry. Recent regulatory developments in Canada and in other countries were then reviewed with arguments for or against deregulation. 28 refs., 2 tabs

  14. Assessing and reducing fine and ultrafine particles inside Los Angeles taxis

    Science.gov (United States)

    Yu, Nu; Shu, Shi; Lin, Yan; Zhu, Yifang

    2018-05-01

    Taxi drivers and passengers are exposed to high levels of traffic-related air pollutants, but their exposures to fine (PM2.5) and ultrafine particles (UFPs) and related mitigation strategies are rarely explored. In this study, UFP and PM2.5 concentrations were monitored concurrently inside and outside of 22 taxis under different ventilation and mitigation conditions. Under realistic working conditions (no mitigation; NM), the average UFP and PM2.5 levels inside taxis were 1.46 × 104 particles/cm3 and 26 μg/m3, respectively. When the taxi ventilation was set to outside air mode and the windows kept closed, in-cabin UFP and PM2.5 concentrations are significantly associated with on-road concentrations, driving speed, and cabin air filter usage. The average in-cabin to on-roadway (I/O) ratios for UFP and PM2.5 were reduced from 0.60 to 0.75 under NM, to 0.47 and 0.52 under the most stringent mitigation strategy of keeping the windows closed and operating a high efficiency cabin air filter (WC + HECA). Among all tested taxi models, Toyota Prius exhibited the lowest UFP and PM2.5 I/O ratios under WC + HECA. Switching cabin air filters from the originally equipped manufacturer filter (OEM) to a HECA filter reduced the UFP and PM2.5 I/O ratios most effectively in Toyota Prius taxis as well.

  15. Research on Strategy Control of Taxi Carpooling Detour Route under Uncertain Environment

    Directory of Open Access Journals (Sweden)

    Wei Zhang

    2016-01-01

    Full Text Available For the problem of route choice in taxi carpooling detour, considering the uncertainty of traffic and the characteristic of passengers’ noncomplete rationality, an evolutionary game model of taxi carpooling detour route is built, in which prospect theory is introduced and revenue of strategy is replaced by prospect value. The model reflects more really decision-making psychology of passengers. Then the stable strategies of the model are studied, and the influences of detour distance and traffic congestion on detour carpooling success are analyzed, respectively. The results show that when at least one route of which prospect values for two passenger sides are both positive exists, carpooling route can reach an agreement. The route is stable strategy of evolutionary game, and the passengers requiring short travel time tend to select the nondetour route. With the increase of detour distance and traffic congestion rate, the possibility of reaching an agreement decreases gradually; that is, possibility of carpooling failure increases. So taxi carpooling detour is possible under the certain condition, but some measures must be carried out such as constraints of detour distance and mitigation of traffic congestion to improve carpooling success probability. These conclusions have a certain guiding significance to the formulation of taxi carpooling policy.

  16. The relation between working conditions, aberrant driving behaviour and crash propensity among taxi drivers in China.

    Science.gov (United States)

    Wang, Yonggang; Li, Linchao; Prato, Carlo G

    2018-04-03

    Although the taxi industry is playing an important role in Chinese everyday life, little attention has been posed towards occupational health issues concerning the taxi drivers' working conditions, driving behaviour and road safety. A cross-sectional survey was administered to 1021 taxi drivers from 21 companies in four Chinese cities and collected information about (i) sociodemographic characteristics, (ii) working conditions, (iii) frequency of daily aberrant driving behaviour, and (iv) involvement in property-damage-only (PDO) and personal injury (PI) crashes over the past two years. A hybrid bivariate model of crash involvement was specified: (i) the hybrid part concerned a latent variable model capturing unobserved traits of the taxi drivers; (ii) the bivariate part modelled jointly both types of crashes while capturing unobserved correlation between error terms. The survey answers paint a gloomy picture in terms of workload, as taxi drivers reported averages of 9.4 working hours per day and 6.7 working days per week that amount on average to about 63.0 working hours per week. Moreover, the estimates of the hybrid bivariate model reveal that increasing levels of fatigue, reckless behaviour and aggressive behaviour are positively related to a higher propensity of crash involvement. Lastly, the heavy workload is also positively correlated with the higher propensity of crashing, not only directly as a predictor of crash involvement, but also indirectly as a covariate of fatigue and aberrant driving behaviour. The findings from this study provide insights into potential strategies for preventive education and taxi industry management to improve the working conditions and hence reduce fatigue and road risk for the taxi drivers. Copyright © 2018 Elsevier Ltd. All rights reserved.

  17. among Taxi Drivers in Addis Ababa, Ethiopia

    African Journals Online (AJOL)

    user

    Long years of driving [AOR =4.6 (95%CI, 1.6-12.9)], involvement in a similar activity prior to becoming taxi driver .... full time taxi driver; produce a valid driving license; .... Self-employee .... professional car drivers in Dhaka city, Bangladesh.

  18. Revealing Spatial Variation and Correlation of Urban Travels from Big Trajectory Data

    Science.gov (United States)

    Li, X.; Tu, W.; Shen, S.; Yue, Y.; Luo, N.; Li, Q.

    2017-09-01

    With the development of information and communication technology, spatial-temporal data that contain rich human mobility information are growing rapidly. However, the consistency of multi-mode human travel behind multi-source spatial-temporal data is not clear. To this aim, we utilized a week of taxies' and buses' GPS trajectory data and smart card data in Shenzhen, China to extract city-wide travel information of taxi, bus and metro and tested the correlation of multi-mode travel characteristics. Both the global correlation and local correlation of typical travel indicator were examined. The results show that: (1) Significant differences exist in of urban multi-mode travels. The correlation between bus travels and taxi travels, metro travel and taxi travels are globally low but locally high. (2) There are spatial differences of the correlation relationship between bus, metro and taxi travel. These findings help us understanding urban travels deeply therefore facilitate both the transport policy making and human-space interaction research.

  19. Spatiotemporal Patterns of Carbon Emissions and Taxi Travel Using GPS Data in Beijing

    Directory of Open Access Journals (Sweden)

    Jinlei Zhang

    2018-02-01

    Full Text Available Taxis are significant contributors to carbon dioxide emissions due to their frequent usage, yet current research into taxi carbon emissions is insufficient. Emerging data sources and big data–mining techniques enable analysis of carbon emissions, which contributes to their reduction and the promotion of low-carbon societies. This study uses taxi GPS data to reconstruct taxi trajectories in Beijing. We then use the carbon emission calculation model based on a taxi fuel consumption algorithm and the carbon dioxide emission factor to calculate emissions and apply a visualization method called kernel density analysis to obtain the dynamic spatiotemporal distribution of carbon emissions. Total carbon emissions show substantial temporal variations during the day, with maximum values from 10:00–11:00 (57.53 t, which is seven times the minimum value of 7.43 t (from 03:00–04:00. Carbon emissions per kilometer at the network level are steady throughout the day (0.2 kg/km. The Airport Expressway, Ring Roads, and large intersections within the 5th Ring Road maintain higher carbon emissions than other areas. Spatiotemporal carbon emissions and travel patterns differ between weekdays and weekends, especially during morning rush hours. This research provides critical insights for taxi companies, authorities, and future studies.

  20. Taxi Time Prediction at Charlotte Airport Using Fast-Time Simulation and Machine Learning Techniques

    Science.gov (United States)

    Lee, Hanbong

    2016-01-01

    Accurate taxi time prediction is required for enabling efficient runway scheduling that can increase runway throughput and reduce taxi times and fuel consumptions on the airport surface. Currently NASA and American Airlines are jointly developing a decision-support tool called Spot and Runway Departure Advisor (SARDA) that assists airport ramp controllers to make gate pushback decisions and improve the overall efficiency of airport surface traffic. In this presentation, we propose to use Linear Optimized Sequencing (LINOS), a discrete-event fast-time simulation tool, to predict taxi times and provide the estimates to the runway scheduler in real-time airport operations. To assess its prediction accuracy, we also introduce a data-driven analytical method using machine learning techniques. These two taxi time prediction methods are evaluated with actual taxi time data obtained from the SARDA human-in-the-loop (HITL) simulation for Charlotte Douglas International Airport (CLT) using various performance measurement metrics. Based on the taxi time prediction results, we also discuss how the prediction accuracy can be affected by the operational complexity at this airport and how we can improve the fast time simulation model before implementing it with an airport scheduling algorithm in a real-time environment.

  1. A cross-sectional study with an improved methodology to assess occupational air pollution exposure and respiratory health in motorcycle taxi driving

    International Nuclear Information System (INIS)

    Lawin, Herve; Agodokpessi, Gildas; Ayelo, Paul; Kagima, Jacqueline; Sonoukon, Rodrigue; Mbatchou Ngahane, Bertrand H.; Awopeju, Olayemi; Vollmer, William M.; Nemery, Benoit; Burney, Peter; Fayomi, Benjamin

    2016-01-01

    Introduction: Motorcycle taxi driving is common in many African cities. This study tested whether this occupation is associated with more respiratory disorders in a context of widespread urban air pollution with an improved methodology. Methods: In a cross sectional study we compared 85 male motorcycle taxi drivers in the capital city of the Republic of Benin (Cotonou) with an age and neighborhood matched control group. All participants carried a portable carbon monoxide data logger for 8 hours per day to assess exposure to air pollution. Respiratory symptoms were obtained using a standardized questionnaire and pulmonary function was assessed by spirometry. Results: The two groups did not differ significantly (p > 0.10) in their age, height, educational level, and exposures to smoke from biomass fuels and tobacco products. The taxi drivers were exposed to higher mean (SD) levels of carbon monoxide (7.6 ± 4.9 ppmvs. 5.4 ± 3.8 ppm p = 0.001). They reported more phlegm and tended to have slightly lower levels of lung function, although these differences were not statistically significant. Conclusion: In this cross sectional study of young motorcycle taxi drivers with substantial exposure to urban traffic and a matched control group, we found no evidence for respiratory impairment. A follow-up of such study population with other pollution exposure surrogate and other clinical endpoint may provide a more robust conclusion regarding the exposure response in this professional group. - Highlights: • Need of improved study method to assess air pollution effect in exposed workers • This study compared motorcycle taxi drivers and a matched control group • Personal carbon monoxide exposure and respiratory disorders were collected • No evidence of more respiratory disorders even though pollutant exposure was higher

  2. A cross-sectional study with an improved methodology to assess occupational air pollution exposure and respiratory health in motorcycle taxi driving

    Energy Technology Data Exchange (ETDEWEB)

    Lawin, Herve, E-mail: hervelawin@yahoo.fr [Unit of Teaching and Research in Occupational and Environmental Health, Department of Public Health, Faculty of Health Sciences, University of Abomey-Calavi (Benin); Agodokpessi, Gildas [Centre National Hospitalier et Universitaire de Pneumo-Phtisiologie, Cotonou (Benin); Ayelo, Paul [Unit of Teaching and Research in Occupational and Environmental Health, Department of Public Health, Faculty of Health Sciences, University of Abomey-Calavi (Benin); Kagima, Jacqueline [Department of internal medicine, Egerton University (Kenya); Sonoukon, Rodrigue [Unit of Teaching and Research in Occupational and Environmental Health, Department of Public Health, Faculty of Health Sciences, University of Abomey-Calavi (Benin); Mbatchou Ngahane, Bertrand H. [Department of Internal Medicine, Douala General Hospital, Cameroon Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala (Cameroon); Awopeju, Olayemi [Department of Medicine, Obafemi Awolowo University, Ile Ife (Nigeria); Vollmer, William M. [Center for Health Research, Kaiser Permanente Northwest, Portland (United States); Nemery, Benoit [Dept. of Public Health, Occupational and Environmental Insurance Medicine, KU Leuven, Leuven (Belgium); Burney, Peter [National Heart & Lung Institute, Imperial College, London (United Kingdom); Fayomi, Benjamin [Unit of Teaching and Research in Occupational and Environmental Health, Department of Public Health, Faculty of Health Sciences, University of Abomey-Calavi (Benin)

    2016-04-15

    Introduction: Motorcycle taxi driving is common in many African cities. This study tested whether this occupation is associated with more respiratory disorders in a context of widespread urban air pollution with an improved methodology. Methods: In a cross sectional study we compared 85 male motorcycle taxi drivers in the capital city of the Republic of Benin (Cotonou) with an age and neighborhood matched control group. All participants carried a portable carbon monoxide data logger for 8 hours per day to assess exposure to air pollution. Respiratory symptoms were obtained using a standardized questionnaire and pulmonary function was assessed by spirometry. Results: The two groups did not differ significantly (p > 0.10) in their age, height, educational level, and exposures to smoke from biomass fuels and tobacco products. The taxi drivers were exposed to higher mean (SD) levels of carbon monoxide (7.6 ± 4.9 ppmvs. 5.4 ± 3.8 ppm p = 0.001). They reported more phlegm and tended to have slightly lower levels of lung function, although these differences were not statistically significant. Conclusion: In this cross sectional study of young motorcycle taxi drivers with substantial exposure to urban traffic and a matched control group, we found no evidence for respiratory impairment. A follow-up of such study population with other pollution exposure surrogate and other clinical endpoint may provide a more robust conclusion regarding the exposure response in this professional group. - Highlights: • Need of improved study method to assess air pollution effect in exposed workers • This study compared motorcycle taxi drivers and a matched control group • Personal carbon monoxide exposure and respiratory disorders were collected • No evidence of more respiratory disorders even though pollutant exposure was higher.

  3. Prediction of safe driving Behaviours based on health belief model: the case of taxi drivers in Bandar Abbas, Iran.

    Science.gov (United States)

    Razmara, Asghar; Aghamolaei, Teamur; Madani, Abdoulhossain; Hosseini, Zahra; Zare, Shahram

    2018-03-20

    Road accidents are among the main causes of mortality. As safe and secure driving is a key strategy to reduce car injuries and offenses, the present research aimed to explore safe driving behaviours among taxi drivers based on the Health Belief Model (HBM). This study was conducted on 184 taxi drivers in Bandar Abbas who were selected based on a multiple stratified sampling method. Data were collected by a questionnaire comprised of a demographic information section along with the constructs of the HBM. Data were analysed by SPSS ver19 via a Pearson's correlation coefficient and multiple regressions. The mean age of the participants was 45.1 years (SD = 11.1). They all had, on average, 10.3 (SD = 7/5) years of taxi driving experience. Among the HBM components, cues to action and perceived benefits were shown to be positively correlated with safe driving behaviours, while perceived barriers were negatively correlated. Cues to action, perceived barriers and perceived benefits were shown to be the strongest predictors of a safe drivers' behaviour. Based on the results of this study in designing health promotion programmes to improve safe driving behaviours among taxi drivers, cues to action, perceived benefits and perceived barriers are important. Therefore, advertising, the design of information campaigns, emphasis on the benefits of safe driving behaviours and modification barriers are recommended.

  4. Fuel cell hybrid taxi life cycle analysis

    Energy Technology Data Exchange (ETDEWEB)

    Baptista, Patricia, E-mail: patricia.baptista@ist.utl.pt [IDMEC-Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Av. Rovisco Pais, 1, 1049-001 Lisboa (Portugal); Ribau, Joao; Bravo, Joao; Silva, Carla [IDMEC-Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Av. Rovisco Pais, 1, 1049-001 Lisboa (Portugal); Adcock, Paul; Kells, Ashley [Intelligent Energy, Charnwood Building, HolywellPark, Ashby Road, Loughborough, LE11 3GR (United Kingdom)

    2011-09-15

    A small fleet of classic London Taxis (Black cabs) equipped with hydrogen fuel cell power systems is being prepared for demonstration during the 2012 London Olympics. This paper presents a Life Cycle Analysis for these vehicles in terms of energy consumption and CO{sub 2} emissions, focusing on the impacts of alternative vehicle technologies for the Taxi, combining the fuel life cycle (Tank-to-Wheel and Well-to-Tank) and vehicle materials Cradle-to-Grave. An internal combustion engine diesel taxi was used as the reference vehicle for the currently available technology. This is compared to battery and fuel cell vehicle configurations. Accordingly, the following energy pathways are compared: diesel, electricity and hydrogen (derived from natural gas steam reforming). Full Life Cycle Analysis, using the PCO-CENEX drive cycle, (derived from actual London Taxi drive cycles) shows that the fuel cell powered vehicle configurations have lower energy consumption (4.34 MJ/km) and CO{sub 2} emissions (235 g/km) than both the ICE Diesel (9.54 MJ/km and 738 g/km) and the battery electric vehicle (5.81 MJ/km and 269 g/km). - Highlights: > A Life Cycle Analysis of alternative vehicle technologies for the London Taxi was performed. > The hydrogen powered vehicles have the lowest energy consumption and CO{sub 2} emissions results. > A hydrogen powered solution can be a sustainable alternative in a full life cycle framework.

  5. Fuel cell hybrid taxi life cycle analysis

    International Nuclear Information System (INIS)

    Baptista, Patricia; Ribau, Joao; Bravo, Joao; Silva, Carla; Adcock, Paul; Kells, Ashley

    2011-01-01

    A small fleet of classic London Taxis (Black cabs) equipped with hydrogen fuel cell power systems is being prepared for demonstration during the 2012 London Olympics. This paper presents a Life Cycle Analysis for these vehicles in terms of energy consumption and CO 2 emissions, focusing on the impacts of alternative vehicle technologies for the Taxi, combining the fuel life cycle (Tank-to-Wheel and Well-to-Tank) and vehicle materials Cradle-to-Grave. An internal combustion engine diesel taxi was used as the reference vehicle for the currently available technology. This is compared to battery and fuel cell vehicle configurations. Accordingly, the following energy pathways are compared: diesel, electricity and hydrogen (derived from natural gas steam reforming). Full Life Cycle Analysis, using the PCO-CENEX drive cycle, (derived from actual London Taxi drive cycles) shows that the fuel cell powered vehicle configurations have lower energy consumption (4.34 MJ/km) and CO 2 emissions (235 g/km) than both the ICE Diesel (9.54 MJ/km and 738 g/km) and the battery electric vehicle (5.81 MJ/km and 269 g/km). - Highlights: → A Life Cycle Analysis of alternative vehicle technologies for the London Taxi was performed. → The hydrogen powered vehicles have the lowest energy consumption and CO 2 emissions results. → A hydrogen powered solution can be a sustainable alternative in a full life cycle framework.

  6. Effectiveness of clean taxi priority incentive at Amsterdam Central Station

    NARCIS (Netherlands)

    van der Flier, A.S.; Dam, J.; van den Hoed, R.

    2017-01-01

    The municipality of Amsterdam wants to have an emission free taxi sector by 2025. In order to reach that goal, the city has taken a number of measures which favour clean taxis above conventional taxis. One of these measures is an innovative priority privilege scheme at the Amsterdam Central Station

  7. Applicative Research on Psychological Demand of Audience and the TAXI for People

    Directory of Open Access Journals (Sweden)

    Zhang Caixia

    2015-01-01

    Full Text Available Whether TAXI for People from Beijing traffic channel, the only special program customized for taxi driver in Beijing, knows about the psychological feature of the certain taxi group is an important factor that affects the development of program. Based on demand theory of psychology, this article uses the questionnaire method to find out the psychological feature and lifestyle of audience, and discusses the degree to the TAXI for People which meets the psychological demand of taxi driver audience by analysis on the program content. It is said from the research that the TAXI for People basically meets the psychological demand from taxi drivers. However, this program shall focus more on their basic needs and provide the opportunity for the audience to participate in the program and activity.

  8. A WEB-BASED PLATFORM FOR VISUALIZING SPATIOTEMPORAL DYNAMICS OF BIG TAXI DATA

    Directory of Open Access Journals (Sweden)

    H. Xiong

    2017-09-01

    Full Text Available With more and more vehicles equipped with Global Positioning System (GPS, access to large-scale taxi trajectory data has become increasingly easy. Taxis are valuable sensors and information associated with taxi trajectory can provide unprecedented insight into many aspects of city life. But analysing these data presents many challenges. Visualization of taxi data is an efficient way to represent its distributions and structures and reveal hidden patterns in the data. However, Most of the existing visualization systems have some shortcomings. On the one hand, the passenger loading status and speed information cannot be expressed. On the other hand, mono-visualization form limits the information presentation. In view of these problems, this paper designs and implements a visualization system in which we use colour and shape to indicate passenger loading status and speed information and integrate various forms of taxi visualization. The main work as follows: 1. Pre-processing and storing the taxi data into MongoDB database. 2. Visualization of hotspots for taxi pickup points. Through DBSCAN clustering algorithm, we cluster the extracted taxi passenger’s pickup locations to produce passenger hotspots. 3. Visualizing the dynamic of taxi moving trajectory using interactive animation. We use a thinning algorithm to reduce the amount of data and design a preloading strategyto load the data smoothly. Colour and shape are used to visualize the taxi trajectory data.

  9. a Web-Based Platform for Visualizing Spatiotemporal Dynamics of Big Taxi Data

    Science.gov (United States)

    Xiong, H.; Chen, L.; Gui, Z.

    2017-09-01

    With more and more vehicles equipped with Global Positioning System (GPS), access to large-scale taxi trajectory data has become increasingly easy. Taxis are valuable sensors and information associated with taxi trajectory can provide unprecedented insight into many aspects of city life. But analysing these data presents many challenges. Visualization of taxi data is an efficient way to represent its distributions and structures and reveal hidden patterns in the data. However, Most of the existing visualization systems have some shortcomings. On the one hand, the passenger loading status and speed information cannot be expressed. On the other hand, mono-visualization form limits the information presentation. In view of these problems, this paper designs and implements a visualization system in which we use colour and shape to indicate passenger loading status and speed information and integrate various forms of taxi visualization. The main work as follows: 1. Pre-processing and storing the taxi data into MongoDB database. 2. Visualization of hotspots for taxi pickup points. Through DBSCAN clustering algorithm, we cluster the extracted taxi passenger's pickup locations to produce passenger hotspots. 3. Visualizing the dynamic of taxi moving trajectory using interactive animation. We use a thinning algorithm to reduce the amount of data and design a preloading strategyto load the data smoothly. Colour and shape are used to visualize the taxi trajectory data.

  10. Predicting Taxi-Out Time at Congested Airports with Optimization-Based Support Vector Regression Methods

    Directory of Open Access Journals (Sweden)

    Guan Lian

    2018-01-01

    Full Text Available Accurate prediction of taxi-out time is significant precondition for improving the operationality of the departure process at an airport, as well as reducing the long taxi-out time, congestion, and excessive emission of greenhouse gases. Unfortunately, several of the traditional methods of predicting taxi-out time perform unsatisfactorily at congested airports. This paper describes and tests three of those conventional methods which include Generalized Linear Model, Softmax Regression Model, and Artificial Neural Network method and two improved Support Vector Regression (SVR approaches based on swarm intelligence algorithm optimization, which include Particle Swarm Optimization (PSO and Firefly Algorithm. In order to improve the global searching ability of Firefly Algorithm, adaptive step factor and Lévy flight are implemented simultaneously when updating the location function. Six factors are analysed, of which delay is identified as one significant factor in congested airports. Through a series of specific dynamic analyses, a case study of Beijing International Airport (PEK is tested with historical data. The performance measures show that the proposed two SVR approaches, especially the Improved Firefly Algorithm (IFA optimization-based SVR method, not only perform as the best modelling measures and accuracy rate compared with the representative forecast models, but also can achieve a better predictive performance when dealing with abnormal taxi-out time states.

  11. REVEALING SPATIAL VARIATION AND CORRELATION OF URBAN TRAVELS FROM BIG TRAJECTORY DATA

    Directory of Open Access Journals (Sweden)

    X. Li

    2017-09-01

    Full Text Available With the development of information and communication technology, spatial-temporal data that contain rich human mobility information are growing rapidly. However, the consistency of multi-mode human travel behind multi-source spatial-temporal data is not clear. To this aim, we utilized a week of taxies’ and buses’ GPS trajectory data and smart card data in Shenzhen, China to extract city-wide travel information of taxi, bus and metro and tested the correlation of multi-mode travel characteristics. Both the global correlation and local correlation of typical travel indicator were examined. The results show that: (1 Significant differences exist in of urban multi-mode travels. The correlation between bus travels and taxi travels, metro travel and taxi travels are globally low but locally high. (2 There are spatial differences of the correlation relationship between bus, metro and taxi travel. These findings help us understanding urban travels deeply therefore facilitate both the transport policy making and human-space interaction research.

  12. Analyzing Urban Human Mobility Patterns through a Thematic Model at a Finer Scale

    Directory of Open Access Journals (Sweden)

    Faming Zhang

    2016-06-01

    Full Text Available Taxi trajectories reflect human mobility over a road network. Pick-up and drop-off locations in different time periods represent origins and destinations of trips, respectively, demonstrating the spatiotemporal characteristics of human behavior. Each trip can be viewed as a displacement in the random walk model, and the distribution of extracted trips shows a distance decay effect. To identify the spatial similarity of trips at a finer scale, this paper investigates the distribution of trips through topic modeling techniques. Firstly, trip origins and trip destinations were identified from raw GPS data. Then, different trips were given semantic information, i.e., link identification numbers with a semantic enrichment process. Each taxi trajectory was composed of a series of trip destinations corresponding to the same taxi. Subsequently, each taxi trajectory was analogous to a document consisting of different words, and all taxi’s trajectories could be regarded as document corpora, enabling a semantic analysis of massive trip destinations. Finally, we obtained different trip destination topics reflecting the spatial similarity and regional property of human mobility through LDA topic model training. The effectiveness of this approach was illustrated by a case study using a large dataset of taxi trajectories collected from 2 to 8 June 2014 in Wuhan, China.

  13. Spatio-temporal pattern formation in predator-prey systems with fitness taxis

    DEFF Research Database (Denmark)

    Heilmann, Irene T.; Thygesen, Uffe Høgsbro; Sørensen, Mads Peter

    2018-01-01

    We pose a spatial predator–prey model in which the movement of animals is not purely diffusive, but also contains a drift term in the direction of higher specific growth rates. We refer to this as fitness taxis. We conduct a linear stability analysis of the resulting coupled reaction–advection–di......We pose a spatial predator–prey model in which the movement of animals is not purely diffusive, but also contains a drift term in the direction of higher specific growth rates. We refer to this as fitness taxis. We conduct a linear stability analysis of the resulting coupled reaction...... of diffusive motion, is ecologically plausible, and provides an alternative mechanism for formation of patterns in spatially explicit ecosystem models, with emphasis on non-stationary spatio-temporal dynamics....

  14. Exploring Spatiotemporal Patterns of Long-Distance Taxi Rides in Shanghai

    Directory of Open Access Journals (Sweden)

    Hangbin Wu

    2017-11-01

    Full Text Available Floating Car Data (FCD has been analyzed for various purposes in past years. However, limited research about the behaviors of taking long-distance taxi rides has been made available. In this paper, we used data from over 12,000 taxis during a six-month period in Shanghai to analyze the spatiotemporal patterns of long-distance taxi trips. We investigated these spatiotemporal patterns by comparing them with metro usage in Shanghai, in order to determine the extent and how the suburban trains divert the passenger flow from taxis. The results identified 12 pick-up and six drop-off hotspots in Shanghai. Overall, the pick-up locations were relatively more concentrated than the drop-off locations. Temporal patterns were also revealed. Passengers on long-distance taxi rides were observed to avoid the rush hours on the street as their first priority and tried to avoid the inconvenience of interchanges on the metro lines as their second priority.

  15. Modeling with Robotran the autonomous electrical taxi and pushback operations of an Airbus A320

    OpenAIRE

    Quinet, Stéphane

    2017-01-01

    Nowadays, commercial flights are very close to a full automation while several means of transport already made the move. Civilian transport airplanes offer the possibility to fly in a fully automated mode from a few seconds after take-off to the exit of the runway - down to 60 knots- after landing. However, three flight sequences are not covered yet by an automated solution : the take-off, the taxi and the pushback. This work is a global approach of an autonomous taxi and pushback system impl...

  16. Transcendence, Taxis, Trust: Richard Kearney and Jacques Derrida

    Directory of Open Access Journals (Sweden)

    Ulrich Schmiedel

    2017-03-01

    Full Text Available Whatever else it takes to drive a taxi, it takes trust. Day after day, the driver has to decide whether the other is or is not trustworthy. I take the taxi as a test case to analyze and assess Richard Kearney’s diacritical hermeneutics of the other. I argue that Kearney functionalizes the concept of transcendence in order to connect the transcendence of the finite other to the transcendence of the infinite other. However, in his central critique of the deconstructionists following Jacques Derrida, Kearney counters his connection. While Kearney’s critique of Derrida’s account of absolute alterity is correct and compelling, I argue that Derrida’s critique of a distinction between the trustworthy other and the non-trustworthy other might be more crucial than Kearney contends. Insisting on openness to the other’s otherness, Derrida provokes any hermeneutic of the other to trust in transcendence. The taxi is taken as a test to illustrate the implications which diacritical and deconstructive drivers might have for evaluating the entanglement of ethics and eschatology—inside and outside the taxi.

  17. Effect of an Educational Program Based on the Health Belief Model to Reduce Cell Phone Usage During Driving in Taxi drivers

    Directory of Open Access Journals (Sweden)

    Babak Moeini

    2014-09-01

    Full Text Available Introduction: Cell phone usage during driving has become a threat to traffic safety. This study aimed to determine the effectiveness of an educational program based on the health belief model to reduce cell phone usage during driving in taxi drivers of Tuyserkan. Materials and Methods: In this quasi-experimental study, 110 taxi drivers younger than 35 years were randomly divided into two experimental and control groups in Tuyserkan, Iran. Data was collected using a questionnaire including the health belief model constructs, knowledge, behaviors of using cell phone and demographic variables. The questionnaires were self-reported. Intervention was three sessions applied in the experimental group. Both groups were followed for two months after the intervention. Finally, data analysis was performed using SPSS- 19 by Chi-square, Independent T-test, Paired T-test and McNemar. Results: The mean scores for the constructs of health belief model (perceived susceptibility, severity, barriers, perceived benefits, self-efficacy and cues to action, knowledge and desired behaviors about the use of cell phone during driving showed no significant differences between the two groups before the intervention. After the educational intervention, significant differences were observed in experimental group compared to control group. After educational intervention, cell phone usage reduced by 35.14% in the experimental group. Conclusion: An educational intervention based on the health belief model could reduce cell phone usage during driving in taxi drivers.

  18. Switching from motorcycle taxi to walking: A case study of transit station access in Bangkok, Thailand

    Directory of Open Access Journals (Sweden)

    Pornraht Pongprasert

    2017-12-01

    Full Text Available This study aims to find the factors affecting residents near transit stations within 1000 m, who are referred to as transit-oriented development (TOD residents, to reduce motorcycle taxi use and encourage walking to stations. These two modes of commuting are the most popular among over 85% of residents. However, motorcycle taxis are the main pedestrian barriers that hinder easy access and walkability in TODs of Bangkok, because they ride, stop, and provide services on sidewalks. From 2013 to 2015, these problems substantially increased the number of motorcycle taxis that are not willing and able to follow the rules. The increasing number of pedestrian accidents on sidewalks is related to the increase in the number of motorcycle taxis. According to a survey on pedestrian safety with 249 respondents, over 25% of walkers feel unsafe to walk, while 40% of motorcycle-taxi users riding to stations do not walk because they are afraid of accidents. In modal split, the share of walking reduces from 76% for areas < 500 m, to 25% for areas between 500 and 1000 m from transit stations, respectively. Hence, the number of motorcycle taxis in the 500–1000 m range is twice as high compared to that within the 500 m area. If motorcycle taxi users would accept a longer walking distance to station by 36 m or would be willing to walk to the station within 9.15 min, 54% of them may switch to walking to stations. Moreover, based on the estimation results of the logistic regression models, middle-adult aged residents, office employees, residents owning a car, and people living far from stations are less likely to walk. Average income households and commuters during non-peak hours tend to use motorcycle taxis more. On the other hand, residents living far from stations tend to use motorcycle taxis less, because most of the motorcycle taxi services are located near transit stations. Keywords: Transit accessibility, Pedestrian, Walkability

  19. Evaluating the accuracy of GPS-based taxi trajectory records

    NARCIS (Netherlands)

    Zheng, Zhong; Rasouli, Soora; Timmermans, Harry

    2014-01-01

    Taxi data are an underused source of travel information. A handful of research has been concerned with the processing of raw taxi GPS data to minimize random error. The study of methods that systematically detect erroneous data has, however, received less attention. Generally, an origin and a

  20. Economic Analysis on Value Chain of Taxi Fleet with Battery-Swapping Mode Using Multiobjective Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Guobao Ning

    2012-01-01

    Full Text Available This paper presents an economic analysis model on value chain of taxi fleet with battery-swapping mode in a pilot city. In the model, economic benefits of charging-swapping station group, taxi company, and taxi driver in the region have been taken into consideration. Thus, the model is a multiobjective function and multiobjective genetic algorithm is used to solve this problem. According to the real data collected from the pilot city, the multiobjective genetic algorithm is tested as an effective method to solve this problem. Furthermore, the effects of price of electricity, price of battery package, life cycle of battery package, cost of battery-swapping devices and infrastructure, and driving mileage per day on the benefits of value holders are analyzed, which provide theoretical and practical reference for the deployment of electric vehicles, for the national subsidy criteria adjusment, technological innovation instruction, commercial mode selection, and infrastructure construction.

  1. REQUIREMENTS FOR DESIGN, EQUIPMENT AND OPERATION MODE OF TAXI VEHICLES

    Directory of Open Access Journals (Sweden)

    Norayr Oganesovich Bludyan

    2015-09-01

    Full Text Available The analysis of international experience in application of requirements for the taxi vehicles design and equipment. The approaches to improvement of cabbing have been defined by determination of requirements for taxi vehicles.

  2. INFLUENCE OF SERVICE QUALITY AND FARE TOWARD CUSTOMER SATISFACTION AND ITS IMPACT ON CUSTOMER LOYALTY OF EXPRESS TAXI IN JAKARTA

    Directory of Open Access Journals (Sweden)

    Mohammad Rizan

    2015-09-01

    Full Text Available The purpose of this study was to: to examine empirically the effect of service quality to customer satisfaction on Express taxi, to examine empirically the effect of fare to customer satisfaction on Express taxi, to examine empirically the effect of customer satisfaction to customer loyalty on Express taxi, to examine empirically the effect of service quality to customer loyalty on Express taxi, and to examine empirically the effect of fare to customer loyalty on Express taxi. Data collection using survey methods. Sample of this study are 200 respondents who have using services of Express taxi more than two times in last three months. Data analysis using SPSS version 23 and SEM (Structural Equation Modeling LISREL version 8.7. Results of hypothesis testing showed: service quality have positive and significant effect on customer satisfaction, fare have positive and significant effect on customer satisfaction, customer satisfaction have positive and significant effect on customer loyalty, service quality have positive and not significant effect to on customer loyalty. fare have positive and significant effect to on customer loyalty. Rated fit model with value of RMSEA 0.043, value of RMR 0.043, value of CMIN/DF 1.88, value of NFI 0.96, value of NNFI 0.98, and value of CFI 0.98. The results of this research beneficial to transportation company, especially Express taxi in Jakarta, to create better strategy in improving customer loyalty.

  3. Health assessment of taxi drivers in the city of Tshwane

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    Tendani S. Ramukumba

    2016-11-01

    Conclusion: The findings implicate that the health status of taxi operators in Tshwane was a serious concern and urgent concerted effort is needed to engage in lifestyle modification of taxi drivers. The need for health promotion and formalised occupational health services was recommended.

  4. Hematocrit levels as cardiovascular risk among taxi drivers in Bangkok, Thailand

    OpenAIRE

    ISHIMARU, Tomohiro; ARPHORN, Sara; JIRAPONGSUWAN, Ann

    2016-01-01

    In Thailand, taxi drivers employed in the informal sector often experience hazardous working conditions. Previous studies revealed that elevated Hematocrit (HCT) is a predictor of cardiovascular disease (CVD) risk. This study assessed factors associated with HCT in taxi drivers to predict their occupational CVD risk factors. A cross-sectional study was conducted on 298 male taxi drivers who joined a health check-up campaign in Bangkok, Thailand. HCT and body mass index were retrieved from par...

  5. Dansk Taxi Råd har brug for et sprogkursus

    DEFF Research Database (Denmark)

    Riis, Helle Bach

    2011-01-01

    16.10. afviser formanden for Dansk Taxi Råd, John Lindbom, at det nyindførte pointsystem har til hensigt at holde indvandrere fra at blive vognmænd. I stedet siger han, at det handler om at højne fagets status og serviceniveau. Dansk Taxi Råd kan komme langt ved at forbedre sin interkulturelle...

  6. Hubungan Upah dan Penawaran Tenaga Kerja Supir Taxi di Surabaya

    Directory of Open Access Journals (Sweden)

    Achmad Solihin

    2014-05-01

    Full Text Available Utilizing 50 (fifty of taxi drivers, who has been observing around 100 (one hundred working days, this study exploring whether the prediction of Neoclassical theory or the Reference Dependence Point (RDP about income targetting are followed by the taxi drivers in Surabaya city. Neoclassical theory assume that workers will respond positively with the transitory wage change, while the Reference Dependence Point, especially income targetting predict there is negative relationship between labor supply and positive wage income transitory. RDP theory predict that workers will decide reducing their working hours or stopping to work when their wage income has exceed their targetted income. Most of the previous studies evaluate the RDP hiphotesis on taxi drivers. In this study we find that among 50 (fifty taxi drivers being observed in Surabaya following the prediction of RDP theory. The point elasticity of labor supply in respond to positive wage changing has been found on the range of -0.004 % to -0.0012%.

  7. Using Spatial Semantics and Interactions to Identify Urban Functional Regions

    Directory of Open Access Journals (Sweden)

    Yandong Wang

    2018-03-01

    Full Text Available The spatial structures of cities have changed dramatically with rapid socio-economic development in ways that are not well understood. To support urban structural analysis and rational planning, we propose a framework to identify urban functional regions and quantitatively explore the intensity of the interactions between them, thus increasing the understanding of urban structures. A method for the identification of functional regions via spatial semantics is proposed, which involves two steps: (1 the study area is classified into three types of functional regions using taxi origin/destination (O/D flows; and (2 the spatial semantics for the three types of functional regions are demonstrated based on point-of-interest (POI categories. To validate the existence of urban functional regions, we explored the intensity of interactions quantitatively between them. A case study using POI data and taxi trajectory data from Beijing validates the proposed framework. The results show that the proposed framework can be used to identify urban functional regions and promotes an enhanced understanding of urban structures.

  8. Prevalence of Psychoactive Drug Use by Taxi Drivers in Nigeria ...

    African Journals Online (AJOL)

    Aim: To ascertain the prevalence and nature of psychoactive drug use amongst taxi drivers in Nigeria. Materials and Method: A total of 192 taxi drivers in Enugu, South East Nigeria was studied using a questionnaire. Information obtained from the questionnaire included socio-demographic characteristics of the drivers, ...

  9. Utilising excess minibus-taxi capacity for South African townships tours

    NARCIS (Netherlands)

    Rietjens, S.J.H.; Makoriwa, Collins; de Boer, S.J.

    2006-01-01

    This paper proposes an option for the utilisation of excess off-peak capacity of minibus-taxis in South Africa for township tours. The minibus-taxi system typically faces steep peak loads during rush hours with excess vehicle and person capacity available during off-hours. The advantages of the

  10. Exploring Intracity Taxi Mobility during the Holidays for Location-Based Marketing

    Directory of Open Access Journals (Sweden)

    Wen-jun Wang

    2017-01-01

    Full Text Available Taxi mobility information can be considered as an important source of mobile location-based information for making marketing decisions. So, studying the behavioral patterns of taxis in a Chinese city during the holidays using the global positioning system (GPS can yield remarkable insights into people’s holiday travel patterns, as well as the odd-even day vehicle prohibition system. This paper studies the behavioral patterns of taxis during specific holidays in terms of pick-up and drop-off locations, travel distance, mobile step length, travel direction, and radius of gyration on the basis of GPS data. Our results support the idea of a polycentric city. It is concluded from the reporting results that there are no significant changes in the distribution of pick-up and drop-off locations, travel distance, or travel direction during holidays in comparison to work days. The results suggest that human travel by taxi has a stable regularity. However, the radius of gyration of movement by most of the taxis becomes significantly larger during holidays that indicate more long-distance travels. The current study will be helpful for location-based marketing during the holidays.

  11. DISPAQ: Distributed Profitable-Area Query from Big Taxi Trip Data.

    Science.gov (United States)

    Putri, Fadhilah Kurnia; Song, Giltae; Kwon, Joonho; Rao, Praveen

    2017-09-25

    One of the crucial problems for taxi drivers is to efficiently locate passengers in order to increase profits. The rapid advancement and ubiquitous penetration of Internet of Things (IoT) technology into transportation industries enables us to provide taxi drivers with locations that have more potential passengers (more profitable areas) by analyzing and querying taxi trip data. In this paper, we propose a query processing system, called Distributed Profitable-Area Query ( DISPAQ ) which efficiently identifies profitable areas by exploiting the Apache Software Foundation's Spark framework and a MongoDB database. DISPAQ first maintains a profitable-area query index (PQ-index) by extracting area summaries and route summaries from raw taxi trip data. It then identifies candidate profitable areas by searching the PQ-index during query processing. Then, it exploits a Z-Skyline algorithm, which is an extension of skyline processing with a Z-order space filling curve, to quickly refine the candidate profitable areas. To improve the performance of distributed query processing, we also propose local Z-Skyline optimization, which reduces the number of dominant tests by distributing killer profitable areas to each cluster node. Through extensive evaluation with real datasets, we demonstrate that our DISPAQ system provides a scalable and efficient solution for processing profitable-area queries from huge amounts of big taxi trip data.

  12. Analysis of the characteristics of taxi services as a prerequisite for their improvement

    Directory of Open Access Journals (Sweden)

    Vujić Nenad

    2014-01-01

    Full Text Available The expansion of services sector is the characteristics of modern and developed societies that influence national economy. Therefore, the analysis of services, as a concept and part of marketing is very significant. In this sense, the paper researches a particular service - the taxi services in the capital of Serbia. Through this research, the authors try to define the groups of customer of taxi services and their preference and attitudes. The research was performed in period May to July 2014, by direct contact with customer of taxi services. The results of research have confirmed the initial hypothesis and provide possibilities for further insight into the way of using taxi services and general circumstances that characterize them in mentioned region. On this basis, it is provided proposals for improvement of taxi services and easier outreach of target groups.

  13. Hybrid Taxis Give Fuel Economy a Lift -Clean Cities Fleet Experiences -

    Energy Technology Data Exchange (ETDEWEB)

    None

    2009-04-01

    The hybrid taxis are able to achieve about twice the gas mileage of a conventional taxi while helping cut gasoline use and fuel costs. Tax credits and other incentives are helping both company owners and drivers make the switch to hybrids.

  14. Aircrafts' taxi noise. Sound power level and directivity frequency band results

    NARCIS (Netherlands)

    Asensio, C.; Pavón, I.; Ruiz, M.; Pagan Munoz, Raul; Recuero, M.

    2009-01-01

    When noise mapping airports, the main noise sources are take offs and landings. But aircrafts' taxi noise can also be important, and should be considered, for instance when there are residential buildings near the airport's terminal. Main prediction tools, like Integrated Noise Model (INM), do not

  15. Hematocrit levels as cardiovascular risk among taxi drivers in Bangkok, Thailand

    Science.gov (United States)

    ISHIMARU, Tomohiro; ARPHORN, Sara; JIRAPONGSUWAN, Ann

    2016-01-01

    In Thailand, taxi drivers employed in the informal sector often experience hazardous working conditions. Previous studies revealed that elevated Hematocrit (HCT) is a predictor of cardiovascular disease (CVD) risk. This study assessed factors associated with HCT in taxi drivers to predict their occupational CVD risk factors. A cross-sectional study was conducted on 298 male taxi drivers who joined a health check-up campaign in Bangkok, Thailand. HCT and body mass index were retrieved from participant health check-up files. Self-administered questionnaires assessed demographics, driving mileage, working hours, and lifestyle. Statistical associations were analyzed using stepwise linear regression. Our results showed that obesity (p=0.007), daily alcohol drinking (p=0.003), and current or past smoking (p=0.016) were associated with higher HCT levels. While working hours were not directly associated with HCT levels in the current study, the effect on overworking is statistically arguable because most participants worked substantially longer hours. Our findings suggest that taxi drivers’ CVD risk may be increased by their unhealthy work styles. Initiatives to improve general working conditions for taxi drivers should take into account health promotion and CVD prevention. The policy of providing periodic health check-ups is important to make workers in the informal sector aware of their health status. PMID:27151439

  16. Considering the effects of ambient particulate matter on the lung function of motorcycle taxi drivers in Bangkok, Thailand.

    Science.gov (United States)

    Arphorn, Sara; Ishimaru, Tomohiro; Hara, Kunio; Mahasandana, Suwisa

    2018-02-01

    The motorcycle taxi drivers of Bangkok have been heavily exposed to high concentrations of PM 10 (particulate matter with an aerodynamic diameter ≤10 μm), and the impact of this on their lungs has been neither documented nor studied. This study examines the association between exposure to PM 10 and lung function decline among motorcycle taxi drivers. A cross-sectional study was conducted in Bangkok between two groups: a subject group of motorcycle taxi drivers and control group of enclosed vehicle taxi drivers. The findings of the Thailand Pollution Control Department were used to estimate the annual ambient PM 10 concentration levels in the metropolis. Pulmonary functions of motorcycle taxi drivers and enclosed vehicle taxi drivers were measured and compared using the Mann-Whitney test. Multiple linear regression analysis was applied to estimate the effects of PM 10 exposure on the lung function of motorcycle taxi drivers. A total of 1283 motorcycle taxi drivers and 600 taxi drivers were investigated. The mean forced expiratory volume in 1 sec/forced vital capacity (FEV 1 /FVC) of the motorcycle taxi drivers was significantly lower than that of the taxi drivers (P Organization (WHO) vehicular emission standards should be recognized and eventually enforced.

  17. Motorcycle safety among motorcycle taxi drivers and nonoccupational motorcyclists in developing countries: A case study of Maoming, South China.

    Science.gov (United States)

    Wu, Connor Y H; Loo, Becky P Y

    2016-01-01

    An increasing number of motorcycle taxis have been involved in traffic crashes in many developing countries. This study examines the characteristics of both motorcycle taxi drivers and nonoccupational motorcyclists, investigates the risks they pose to road safety, and provides recommendations to minimize their risks. Based on the data collected from a questionnaire survey of 867 motorcycle taxi drivers and 2,029 nonoccupational motorcyclists in Maoming, South China, comparisons were made to analyze differences of personal attributes, attitudes toward road safety, and self-reported behavior of the 2 groups. Results of the chi-square tests show that not only motorcycle taxi drivers but also nonoccupational motorcyclists in Maoming held poor attitudes toward road safety and both groups reported unsafe driving behavior. There is much room for improving local road safety education among all motorcyclists in Maoming. Yet, motorcycle taxi drivers were more likely to pose road safety risks than nonoccupational motorcyclists under some circumstances, such as speeding late at night or early in the morning, not requiring passengers to wear helmets, and running a red light. The results of the binary logistic regression model show that possessing a vehicle license for a motorcycle or not was the common significant predictor for unsafe driving behavior of motorcycle taxi drivers and nonoccupational motorcyclists. Therefore, enforcement against all motorcyclists not showing vehicle licenses for their motorcycles should be stepped up. Motorcycle safety is largely poor in Maoming. Therefore, efforts to improve motorcycle safety should be strengthened by targeting not only motorcycle taxi drivers but also nonoccupational motorcyclists.

  18. Driving fatigue in professional drivers: a survey of truck and taxi drivers.

    Science.gov (United States)

    Meng, Fanxing; Li, Shuling; Cao, Lingzhi; Li, Musen; Peng, Qijia; Wang, Chunhui; Zhang, Wei

    2015-01-01

    Fatigue among truck drivers has been studied extensively; however, less is known regarding the fatigue experience of taxi drivers in heavily populated metropolitan areas. This study aimed to compare the differences and similarities between truck and taxi driver fatigue to provide implications for the fatigue management and education of professional drivers. A sample of 274 truck drivers and 286 taxi drivers in Beijing was surveyed via a questionnaire, which included items regarding work characteristics, fatigue experience, accident information, attitude toward fatigue, and methods of counteracting fatigue. Driver fatigue was prevalent among professional drivers, and it was even more serious for taxi drivers. Taxi drivers reported more frequent fatigue experiences and were involved in more accidents. Among the contributing factors to fatigue, prolonged driving time was the most important factor identified by both driver groups. Importantly, the reason for the engagement in prolonged driving was neither due to the lack of awareness concerning the serious outcome of fatigue driving nor because of their poor detection of fatigue. The most probable reason was the optimism bias, as a result of which these professional drivers thought that fatigue was more serious for other drivers than for themselves, and they thought that they were effective in counteracting the effect of fatigue on their driving performance. Moreover, truck drivers tended to employ methods that require stopping to counteract fatigue, whereas taxi drivers preferred methods that were simultaneous with driving. Although both driver groups considered taking a nap as one of the most effective means to address fatigue, this method was not commonly used. Interestingly, these drivers were aware that the methods they frequently used were not the most effective means to counteract fatigue. This study provides knowledge on truck and taxi drivers' characteristics in fatigue experience, fatigue attitude, and

  19. Hybrid Taxis Give Fuel Economy a Lift, Clean Cities, Fleet Experiences, April 2009 (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2009-04-01

    Clean Cities helped Boston, San Antonio, and Cambridge create hybrid taxi programs. The hybrid taxis are able to achieve about twice the gas mileage of a conventional taxi while helping cut gasoline use and fuel costs. Tax credits and other incentives are helping both company owners and drivers make the switch to hybrids. Program leaders have learned some important lessons other cities can benefit from including learning a city's taxi structure, relaying benefits to drivers, and understanding the needs of owners.

  20. Cost Reduction of Taxi Enterprises at the Expense of Automobile Fleet Optimization

    Directory of Open Access Journals (Sweden)

    Novytskyi А.V.

    2016-05-01

    Full Text Available Results of taxi service operation using techniques of queuing system theory have been demonstrated. It has been shown that probability of service denial is the key quality criterion of transport services for taxi services. It is expedient to use total expenditures of queuing system as target function to estimate the efficiency of taxi service. It has been determined that application of queuing theory techniques makes it possible to identify optimum value of the number of operating motor vehicles for specific environment. The value is optimum according to minimum-cost criterion.

  1. DISPAQ: Distributed Profitable-Area Query from Big Taxi Trip Data †

    Science.gov (United States)

    Putri, Fadhilah Kurnia; Song, Giltae; Rao, Praveen

    2017-01-01

    One of the crucial problems for taxi drivers is to efficiently locate passengers in order to increase profits. The rapid advancement and ubiquitous penetration of Internet of Things (IoT) technology into transportation industries enables us to provide taxi drivers with locations that have more potential passengers (more profitable areas) by analyzing and querying taxi trip data. In this paper, we propose a query processing system, called Distributed Profitable-Area Query (DISPAQ) which efficiently identifies profitable areas by exploiting the Apache Software Foundation’s Spark framework and a MongoDB database. DISPAQ first maintains a profitable-area query index (PQ-index) by extracting area summaries and route summaries from raw taxi trip data. It then identifies candidate profitable areas by searching the PQ-index during query processing. Then, it exploits a Z-Skyline algorithm, which is an extension of skyline processing with a Z-order space filling curve, to quickly refine the candidate profitable areas. To improve the performance of distributed query processing, we also propose local Z-Skyline optimization, which reduces the number of dominant tests by distributing killer profitable areas to each cluster node. Through extensive evaluation with real datasets, we demonstrate that our DISPAQ system provides a scalable and efficient solution for processing profitable-area queries from huge amounts of big taxi trip data. PMID:28946679

  2. Greening London's black cabs: a study of driver's preferences for fuel cell taxis

    International Nuclear Information System (INIS)

    Mourato, Susana; Saynor, Bob; Hart, David

    2004-01-01

    Road transport accounts for about a quarter of all carbon emissions in the UK, highlighting the need for low carbon alternatives to current fuels and vehicles. Running on hydrogen and virtually emissions-free, fuel cell vehicles are considered to be one of the most promising ways of reducing transport-related emissions. Understanding the user benefits of fuel cell vehicles and the determinants of demand is essential for their successful penetration. This contingent valuation study investigates the preferences of London taxi drivers for driving emissions-free hydrogen fuel cell taxis, both in the short term as part of a pilot project, and in the longer term if production line fuel cell taxis become available. The results show that willingness to pay to participate in a pilot project seems to be driven mostly by drivers' expectation of personal financial gains. In contrast, however, environmental considerations are found to affect taxi drivers' longer-term vehicle purchasing decisions. The results also reveal that driving hydrogen-fuelled vehicles does not seem to raise safety concerns amongst taxi drivers

  3. Respiratory symptoms and lung function in garage workers and taxi drivers.

    Science.gov (United States)

    Bener, A; Galadari, I; al-Mutawa, J K; al-Maskari, F; Das, M; Abuzeid, M S

    1998-12-01

    The aim of this study was to determine the prevalence of some respiratory symptoms and possible diseases among occupationally-exposed garage workers and taxi drivers. This study involved 158 garage workers and 165 taxi drivers, matched for age, sex, nationality and duration of employment. The mean age of 158 Indian subcontinent garage workers was 34.4 +/- 10.4 years; their mean height and weight were 167.7 +/- 6.6 cm and 72.0 +/- 12.3 kg respectively, and the mean duration of employment garage workers was 8.8 +/- 7.6 years. The mean age of 165 Indian subcontinent male taxi drivers was 34.5 +/- 7.7 years; their mean height and weight were 168.7 +/- 6.1 cm and 71.3 +/- 12.6 kg respectively; and the mean duration of employment was 7.5 +/- 5.4 years. The data on chronic respiratory symptoms showed that garage workers had higher prevalence of symptoms than taxi drivers being significantly greater for chronic phlegm, (p UAE), may be associated with the development of chronic respiratory symptoms and have effects on their daily life and health.

  4. Safety Risk of Mobile Phone Use while Driving in Sample of Taxi Drivers

    OpenAIRE

    Murat Darçın; Murat Alkan

    2015-01-01

    Previous research has shown that mobile phone use while driving increases the risk of being involved in an accident. This paper investigates the reported frequency of taxi drivers' mobile phone use and its effects on traffic safety. A representative sample of taxi drivers was included in an interview-based survey by trained interviewers. It was found that 81% of the taxi drivers reported talking by using hand-held phone while driving. There is a relationship between the phoning while driving ...

  5. The xylanase inhibitor TAXI-III counteracts the necrotic activity of a Fusarium graminearum xylanase in vitro and in durum wheat transgenic plants.

    Science.gov (United States)

    Moscetti, Ilaria; Faoro, Franco; Moro, Stefano; Sabbadin, Davide; Sella, Luca; Favaron, Francesco; D'Ovidio, Renato

    2015-08-01

    The xylanase inhibitor TAXI-III has been proven to delay Fusarium head blight (FHB) symptoms caused by Fusarium graminearum in transgenic durum wheat plants. To elucidate the molecular mechanism underlying the capacity of the TAXI-III transgenic plants to limit FHB symptoms, we treated wheat tissues with the xylanase FGSG_03624, hitherto shown to induce cell death and hydrogen peroxide accumulation. Experiments performed on lemmas of flowering wheat spikes and wheat cell suspension cultures demonstrated that pre-incubation of xylanase FGSG_03624 with TAXI-III significantly decreased cell death. Most interestingly, a reduced cell death relative to control non-transgenic plants was also obtained by treating, with the same xylanase, lemmas of TAXI-III transgenic plants. Molecular modelling studies predicted an interaction between the TAXI-III residue H395 and residues E122 and E214 belonging to the active site of xylanase FGSG_03624. These results provide, for the first time, clear indications in vitro and in planta that a xylanase inhibitor can prevent the necrotic activity of a xylanase, and suggest that the reduced FHB symptoms on transgenic TAXI-III plants may be a result not only of the direct inhibition of xylanase activity secreted by the pathogen, but also of the capacity of TAXI-III to avoid host cell death. © 2014 BSPP AND JOHN WILEY & SONS LTD.

  6. Calidad del servicio de taxis del municipio Maracaibo

    Directory of Open Access Journals (Sweden)

    Joheni A. Urdaneta G.

    2011-05-01

    Full Text Available El presente trabajo tiene como objetivo describir la calidad del servicio de los taxis en el municipio Maracaibo, ya que los mismos forman parte del sistema de transporte urbano de la ciudad, y es un servicio público fundamental para la convivencia de la sociedad; para lograr este objetivo se realizó una adaptación del modelo SERVPERF, diseñando un instrumento tipo cuestionario, con 32 ítems en 6 dimensiones, adecuado a las características propias del servicio de taxi, con la finalidad de confirmar que los ítems de los instrumentos se correspondían con las dimensiones adaptadas se aplicó la técnica de análisis factorial resultando un nuevo instrumento con 24 ítems en 3 dimensiones. Se utilizó la escala de Likert con tres (3 alternativas de respuesta. La investigación es de tipo descriptiva y aplicada, bajo diseño no experimental de tipo transeccional descriptiva y de campo. La población quedó conformada por los usuarios de las líneas de taxis del municipio Maracaibo. Se aplicó muestreo aleatorio por conglomerado. La confiabilidad del instrumento se midió a través del coeficiente alfa de Cronbach resultando de 0,82 lo cual se considera aceptable. Los resultados revelan que la calidad del servicio de taxis del municipio Maracaibo es mediana por lo tanto este servicio es susceptible a mejoras, las cuales son necesarias para elevar la calidad de vida de los marabinos. Este resultado se obtuvo con el instrumento originalmente adaptado de 32 ítems y con el cuestionario resultante del análisis factorial, de 24 ítems; esto confirma lo apropiado de esta técnica, ya que se redujo el número de ítems y de las dimensiones originalmente adaptadas y no se encontraron diferencias significativas en los resultados con ambos instrumentos; de esta manera se puede medir la calidad del servicio de taxis en el municipio Maracaibo a través de las dimensiones: confiabilidad del servicio, socialización y responsabilidad.

  7. Assessment of exposure to whole body vibration in Yazd city taxi drivers

    Directory of Open Access Journals (Sweden)

    F Samoori sakhvidi

    2016-11-01

    Full Text Available Assessment of exposure to whole body vibration in Yazd city taxi drivers Samoori-Sakhvidi F (MSc* Barkhordari A (PhD** Dehghani A (PhD*** Tavakoli-Manesh S (MSc**** *Corresponding Author: MSc Student in Department of Occupational Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran ** Professor, Department of Occupational Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran *** Professor, Department of Statistics and Epidemiology, Shahid Sadoughi University of Medical Sciences, Yazd, Iran **** MSc Student in Department of Occupational Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran Abstract Introduction: One of the most common sources of whole body vibration are vehicles in which the driver is exposed to vibration caused by the vehicle and the road. Including the people who continuously exposure to whole-body vibration can be noted to taxi drivers. Taxi drivers during their work shift Encountered with numerous deleterious effects such as noise, vibration, air pollution, and psychological stress and long work shifts. Long-term exposure to whole body vibration in the taxi drivers can communicate with adverse effects such as reduce perception, annoyance, disturbance of vision and fine motor tasks, spinal cord injury, damage to the digestive and reproductive systems. The purpose of this study was cross - sectional study of whole body vibration exposure in Yazd city taxi drivers. Methods: This study was designed to evaluate exposure to whole body vibration in taxi drivers, vibration measurement Was carried out in 80 taxi from 3 vehicle (Samand-Peugeot 405 and Pridein 3 mileage groups, with 63 male drivers and 17 female drivers. parameters Including the vibration Weighing the acceleration frequency (rms, Equivalent acceleration (Aeq and vibration doseVDV in 3-axis was recorded. The results obtained were compared with the values recommended by the standard (ISO 2631-1. Results: The mean (rms acceleration

  8. Characterisation and social impact of urban youth languages on urban toponymy: S’ncamtho toponomastics in Bulawayo

    Directory of Open Access Journals (Sweden)

    Sambulo Ndlovu

    2018-02-01

    Full Text Available This article focuses on the characterisation of S’ncamtho toponyms in Bulawayo and it goes on to measure the impact of these toponyms on the population of Bulawayo dwellers. S’ncamtho is an urban youth variety that is built on urbanity and streetwise style. The study assumes that, as S’ncamtho is the language of the youth in Bulawayo, people are exposed to S’ncamtho toponyms as the youth are found in all spheres of urban life in Bulawayo, especially the taxi industry which is used by the majority of people in the city. The research collected S’ncamtho verbal toponyms from Godini taxi rank in Bulawayo through undisclosed nonparticipant observations and some from the intuition of the researcher. Intuition and interviews were used to get the etymology of the toponyms and questionnaire tests of familiarity and usage were used to measure the impact of these toponyms on the population. Content analysis is used to characterise and classify S’ncamtho toponyms in Bulawayo and the metaphor comprehension test is used to measure their impact on the population. This article assumes that S’ncamtho has its own toponyms for locations in the city and that these are popular, especially with the youth, but people across age groups now use them.

  9. Filters from taxis air conditioning system: A tool to characterize driver's occupational exposure to bioburden?

    Science.gov (United States)

    Viegas, Carla; Monteiro, Ana; Dos Santos, Mateus; Faria, Tiago; Caetano, Liliana Aranha; Carolino, Elisabete; Quintal Gomes, Anita; Marchand, Geneviève; Lacombe, Nancy; Viegas, Susana

    2018-07-01

    Bioburden proliferation in filters from air conditioning systems of taxis represents a possible source of occupational exposure. The aim of this study was to determine the occurrence of fungi and bacteria in filters from the air conditioning system of taxis used for patient transportation and to assess the exposure of drivers to bioburden. Filters from the air conditioning systems of 19 taxis and 28 personal vehicles (used as controls) operating in three Portuguese cities including the capital Lisbon, were collected during the winter season. The occurrence and significance of bioburden detected in the different vehicles are reported and discussed in terms of colony-forming units (CFU) per 1 m 2 of filter area and by the identification of the most frequently detected fungal isolates based on morphology. Azole-resistant mycobiota, fungal biomass, and molecular detection of Aspergillus species/strains were also determined. Bacterial growth was more prevalent in taxis (63.2%) than in personal vehicles (26.3%), whereas fungal growth was more prevalent in personal vehicles (53.6%) than in taxis (21.1-31.6%). Seven different azole-resistant species were identified in this study in 42.1% taxi filters. Levels of fungal biomass were above the detection limit in 63% taxi filters and in 75% personal vehicle filters. No toxigenic species were detected by molecular analysis in the assessed filters. The results obtained show that bioburden proliferation occurs widely in filters from the air conditioning systems of taxis, including the proliferation of azole-resistant fungal species, suggesting that filters should be replaced more frequently. The use of culture based-methods and molecular tools combined enabled an improved risk characterization in this setting. Copyright © 2018 Elsevier Inc. All rights reserved.

  10. A Geo-Aware Taxi Carrying Management System by Using Location Based Services and Zone Queuing Techniques on Internet of Things

    Directory of Open Access Journals (Sweden)

    Chyi-Ren Dow

    2016-01-01

    Full Text Available Taxi plays a crucial role in the transportation system because of the characteristic that can be hailed conveniently. Most of the taxi drivers obtain passengers by hunting on the road or waiting in a fixed taxi queuing point; however these methods have poor performance, high vacancy rate, and several critical problems such as air pollution and foul up traffic. This study proposed a taxi carrying management system by using location based services and zone queuing techniques on Internet of things. The proposed system allows drivers to both hunt on the road and wait in a queuing zone. A queuing table is used in the control center and neighbor tables are used in RSUs for zone queuing establishment. Joining and leaving mechanisms are developed for zone queuing management. To enhance service efficiency and quality, we present a scheme to prevent the ping-pong effect which is based on the location based services, a hunting rate calculation scheme, and a path planning service for taxi drivers according to the history carrying record. PRISM is used to simulate the proposed system, and the results indicated that our scheme outperforms the waiting and hunting models in terms of number of customers, vacancy rate, and profit.

  11. Discovering urban mobility patterns with PageRank based traffic modeling and prediction

    Science.gov (United States)

    Wang, Minjie; Yang, Su; Sun, Yi; Gao, Jun

    2017-11-01

    Urban transportation system can be viewed as complex network with time-varying traffic flows as links to connect adjacent regions as networked nodes. By computing urban traffic evolution on such temporal complex network with PageRank, it is found that for most regions, there exists a linear relation between the traffic congestion measure at present time and the PageRank value of the last time. Since the PageRank measure of a region does result from the mutual interactions of the whole network, it implies that the traffic state of a local region does not evolve independently but is affected by the evolution of the whole network. As a result, the PageRank values can act as signatures in predicting upcoming traffic congestions. We observe the aforementioned laws experimentally based on the trajectory data of 12000 taxies in Beijing city for one month.

  12. Deployment Strategy for Car-Sharing Depots by Clustering Urban Traffic Big Data Based on Affinity Propagation

    Directory of Open Access Journals (Sweden)

    Zhihan Liu

    2018-01-01

    Full Text Available Car sharing is a type of car rental service, by which consumers rent cars for short periods of time, often charged by hours. The analysis of urban traffic big data is full of importance and significance to determine locations of depots for car-sharing system. Taxi OD (Origin-Destination is a typical dataset of urban traffic. The volume of the data is extremely large so that traditional data processing applications do not work well. In this paper, an optimization method to determine the depot locations by clustering taxi OD points with AP (Affinity Propagation clustering algorithm has been presented. By analyzing the characteristics of AP clustering algorithm, AP clustering has been optimized hierarchically based on administrative region segmentation. Considering sparse similarity matrix of taxi OD points, the input parameters of AP clustering have been adapted. In the case study, we choose the OD pairs information from Beijing’s taxi GPS trajectory data. The number and locations of depots are determined by clustering the OD points based on the optimization AP clustering. We describe experimental results of our approach and compare it with standard K-means method using quantitative and stationarity index. Experiments on the real datasets show that the proposed method for determining car-sharing depots has a superior performance.

  13. Prevalence and factors associated with road traffic crash among taxi drivers in Hanoi, Vietnam.

    Science.gov (United States)

    La, Quang Ngoc; Lee, Andy H; Meuleners, Lynn B; Van Duong, Dat

    2013-01-01

    Injury due to road traffic crash is a major cause of ill health and premature deaths in developing countries. Taxis provide a main mode of public transport in Vietnam but there has been little research on the risk of crash for taxi drivers. This retrospective study collected information on taxi crashes for the period 2006-2009 by interviewing drivers from five taxi companies in Hanoi, Vietnam, using a structured questionnaire. Of the total 1214 participants recruited, 276 drivers reported at least one crash, giving an overall crash prevalence of 22.7%. Among the crashed group, 50 drivers (18.1%) were involved in two to four crashes. Logistic regression analysis further identified age of driver, type of driving licence, employment status, perceived sufficiency of income, seat-belt usage, and traffic infringement history to be significantly associated with the crash risk. Further prospective and qualitative studies are recommended to provide detailed crash characteristics as well as behaviour and perception of taxi drivers, so that an effective intervention can be developed to improve road safety and to prevent injury of these commercial drivers. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. Developing a Decision-Support-Tool for an Air Taxi Service in Western Europe

    NARCIS (Netherlands)

    Van Wee, G.P.; Van Nes, R.; Van Duin, J.H.R.; Sengers, P.; Ghijs, S.S.A.

    2008-01-01

    This paper is a research proposal to develop a tool to analyze logistic concepts of the air taxi service of Aeolus Aviation in different scenarios. Based on this analysis recommendations can be done for a suitable logistic concept for Aeolus. Based on background analysis of the air taxi service

  15. Safety Risk of Mobile Phone Use while Driving in Sample of Taxi Drivers

    Directory of Open Access Journals (Sweden)

    Murat Darçın

    2015-08-01

    Full Text Available Previous research has shown that mobile phone use while driving increases the risk of being involved in an accident. This paper investigates the reported frequency of taxi drivers' mobile phone use and its effects on traffic safety. A representative sample of taxi drivers was included in an interview-based survey by trained interviewers. It was found that 81% of the taxi drivers reported talking by using hand-held phone while driving. There is a relationship between the phoning while driving and drivers' self-reported involvement in a dangerous situation. It is clear that the use of mobile phone while driving is an important traffic safety issue.

  16. 76 FR 33639 - Safety Zone; New York Water Taxi 10th Anniversary Fireworks

    Science.gov (United States)

    2011-06-09

    ...-AA00 Safety Zone; New York Water Taxi 10th Anniversary Fireworks, Upper New York Bay, Red Hook, NY... New York Water Taxi. The fireworks will commence at 9 p.m. on June 21, 2011 and will last... CFR Part 165 Harbors, Marine safety, Navigation (water), Reporting and recordkeeping requirements...

  17. Urban Re-qualification and New Centralization in Quelimane, Mozambique

    Directory of Open Access Journals (Sweden)

    Klayde Karmila Gaspar Evaristo

    2017-12-01

    Full Text Available This essay analyses urban restructuring caused by the introduction of new economic activities undertaken by private sector agents in Quelimane, Mozambique. The research investigated the process of urbanization and expansion of the city, economic dynamics and production of urban space, the growth of commerce and specialized services, social inequality and socio-spatial precariousness. The study seeks to demonstrate how issues related to the economic activities, agents and roles of actors in the process of urban restructuring are portrayed. A qualitative approach was used, involving interviews of key actors. The research revealed that urban restructuring in Quelimane in the recent past occurred informally and spontaneously as it still does today. Urban expansion reflects occupational models, the most expressive being economic activities undertaken by small and medium enterprises involving hotels, the provision of specialized goods and services, commerce, civil construction, entertainment and passenger transport in bicycle taxis. The study suggests that in the process of urban restructuring planners must be morecareful to embrace excluded actors. Similarly, the process of urban restructuring and city expansion must follow models of urban re-qualification based not only on official norms but which also take indigenous knowledge into account. This is fundamental in times of globalization in order to accommodate political, cultural and socio-economic functional systems.

  18. Taxi ! méthode de français : niveau 3

    CERN Document Server

    Johnson, Anne-Marie

    2004-01-01

    Taxi ! 3 est une méthode interactive, qui développe non seulement les connaissances, mais aussi les savoir-faire et les savoir-être de l'apprenant, à l'écrit comme à l'oral. La méthode est très simple à utiliser : une leçon = une double page. Taxi ! 3 couvre le niveau Bl du Cadre européen commun de référence pour l'apprentissage, l'enseignement et l'évaluation des langues. La méthode permet de se préparer aux épreuves A3 et A4 du DELF 1er degré. Une progression et des contenus fonctionnels et langagiers solides permettent à l'apprenant d'atteindre rapidement une autonomie en français dans des situations de la vie courante. Taxi ! 3 permet de mieux connaître la France d'aujourd'hui et les comportements des Français à travers une grande variété de documents authentiques (écrit et audio).

  19. [Association between psychosocial aspects of work and quality of life among motorcycle taxi drivers].

    Science.gov (United States)

    Teixeira, Jules Ramon Brito; Boery, Eduardo Nagib; Casotti, Cezar Augusto; Araújo, Tânia Maria de; Pereira, Rafael; Ribeiro, Ícaro José Santos; Rios, Marcela Andrade; Amorim, Camila Rego; Moreira, Ramon Missias; Boery, Rita Narriman Silva de Oliveira; Sales, Zenilda Nogueira

    2015-01-01

    This study aimed to evaluate the quality of life of motorcycle taxi drivers and the association with psychosocial characteristics of their work. This was a cross-sectional epidemiological study with a sample of 400 motorcycle taxi drivers in Jequié, Bahia State, Brazil. The study used a form containing demographic and socioeconomic data, WHO Quality of Life-Bref Questionnaire (WHOQOL-Bref), and the Job Content Questionnaire (JCQ). Motorcycle taxi drivers with greater decision-making control over their work showed better self-rated quality of life in the psychological domain; those with high psychological demands presented better self-rated quality of life in the social relations and environmental domains; those with high strain and active work showed better self-rated quality of life in the social and environmental domains. The psychosocial work environment and especially decision-making autonomy were thus important determinants of self-rated quality of life in this group of motorcycle taxi drivers.

  20. Addressing the minimum fleet problem in on-demand urban mobility.

    Science.gov (United States)

    Vazifeh, M M; Santi, P; Resta, G; Strogatz, S H; Ratti, C

    2018-05-01

    Information and communication technologies have opened the way to new solutions for urban mobility that provide better ways to match individuals with on-demand vehicles. However, a fundamental unsolved problem is how best to size and operate a fleet of vehicles, given a certain demand for personal mobility. Previous studies 1-5 either do not provide a scalable solution or require changes in human attitudes towards mobility. Here we provide a network-based solution to the following 'minimum fleet problem', given a collection of trips (specified by origin, destination and start time), of how to determine the minimum number of vehicles needed to serve all the trips without incurring any delay to the passengers. By introducing the notion of a 'vehicle-sharing network', we present an optimal computationally efficient solution to the problem, as well as a nearly optimal solution amenable to real-time implementation. We test both solutions on a dataset of 150 million taxi trips taken in the city of New York over one year 6 . The real-time implementation of the method with near-optimal service levels allows a 30 per cent reduction in fleet size compared to current taxi operation. Although constraints on driver availability and the existence of abnormal trip demands may lead to a relatively larger optimal value for the fleet size than that predicted here, the fleet size remains robust for a wide range of variations in historical trip demand. These predicted reductions in fleet size follow directly from a reorganization of taxi dispatching that could be implemented with a simple urban app; they do not assume ride sharing 7-9 , nor require changes to regulations, business models, or human attitudes towards mobility to become effective. Our results could become even more relevant in the years ahead as fleets of networked, self-driving cars become commonplace 10-14 .

  1. Institutional statism: an overview of the formulation of the taxi recapitalisation policy

    Directory of Open Access Journals (Sweden)

    D. van Schalkwyk

    2008-07-01

    Full Text Available This article provides an overview of the government’s formulation of the taxi recapitalisation policy which is aimed at regulating the minibus taxi industry. Coupled with a brief social and politico-historical context of the policy, the aim is to highlight the government’s statist conduct in the formulation of the recapitalisation policy. The minibus taxi industry started to fulfil a prominent role in the 1970s as a result of a loophole in the legislation of the former apartheid government. It is currently the most accessible mode of public transport and conveys 65 per cent of the country’s commuters daily. Consequently, the Industry is an imperative force to be considered by the government in its formulation of transport policies. However, the industry is characterised by numerous problems, including a high rate of minibus taxis involved in accidents, unroadworthy vehicles and violence. It is in this context that the government formulated both the original and revised versions of the recapitalisation policy. However, the formulation of the policy has been problematic. The government followed a statist approach during the formulation process when it directed the course of the process according to its interests and without adequate consultation with relevant role players.

  2. Terminal area automatic navigation, guidance, and control 1: Automatic rollout, turnoff, and taxis

    Science.gov (United States)

    Pines, S.

    1981-01-01

    A study developed for the TCV B-737, designed to apply existing navigation aids plus magnetic leader cable signals and develop breaking and reverse thrust guidance laws to provide for rapid automated rollout, turnoff, and taxi to reduce runway occupation time for a wide variety of landing conditions for conventional commercial-type aircraft, is described. Closed loop guidance laws for braking and reverse thrust are derived for rollout, turnoff, and taxi, as functions of the landing speed, the desired taxi speed and the distance to go. Brake limitations for wet runway conditions and reverse thrust limitations are taken into account to provide decision rules to avoid tire skid and to choose an alternate turnoff point, farther down the runway, to accommodate extreme landing conditions.

  3. Het CBb en 'Der digitale Taxi-Krieg'

    NARCIS (Netherlands)

    Westerveld, M.

    2015-01-01

    UberPOP, the taxi service company that claims to be based on the concept of shared economy, offering a positive effect on mobility, environment and usage of energy, in reality confronts us with the question whether we are able to protect 'on demand' workers against exploitation and underpayment. The

  4. Estimation of directivity and sound power levels emitted by aircrafts during taxiing, for outdoor noise prediction purpose

    NARCIS (Netherlands)

    Asensio, C.; Pavón, I.; Ruiz, M.; Pagan Munoz, Raul; Recuero, M.

    2007-01-01

    Integrated noise model (INM) is the most internationally used software to calculate noise levels near airports. Take off, landing or pass by operations can be modeled by INM, but it does not consider aircrafts taxiing, which, in some cases, can be important to accurately evaluate and reduce

  5. Large-scale deployment of electric taxis in Beijing: A real-world analysis

    International Nuclear Information System (INIS)

    Zou, Yuan; Wei, Shouyang; Sun, Fengchun; Hu, Xiaosong; Shiao, Yaojung

    2016-01-01

    The national and municipal government of China enacted a series of regulations and policies to stimulate/promote the development of new energy vehicles, in order to mitigate the increasingly serious carbon emissions, environmental pollution, and energy shortage. As a large metropolitan and populated city subject to the notorious air pollution, Beijing has been making a remarkable progress in the large-scale demonstration of new energy vehicles in recent years, which could result in a significant impact on both transport and electricity sectors. As a result, there is an urgent necessity to study the characteristics of the large-scale new energy vehicles adoption for a deep understanding of operational status (e.g., energy consumption and battery charging patterns) and benefits, as well as charging facilities. Based on the operational data collected from realistic electric-taxi demonstration in Beijing, the driver behavior and charging characteristics are examined in this paper. The energy consumption and efficiency of two representative electric-taxi platforms are compared, and the influence of the driving schedules is discussed. The results show that the average driving distance per day of these electric taxes is 117.98 km, and 92% of drivers recharge their cars twice per day. Further study shows that the drivers make two trips per day, and the two peaks in the distribution of departure and arrival times coincide with the rush hour in the morning and evening. The taxi recharge duration is largely influenced by the charging power. Generally, the associated battery SOC (state of charge) swing is between 40% and 100%. By evaluating the energy consumption of 282 trips recorded in 2013 and 2014, we find that the two platforms have similar energy efficiency. The micro-trips method is utilized to probe the correlation of energy consumption and average speed. - Highlights: • Electric taxis' driver behavior and charging characteristics is analyzed based on operation data

  6. Inconvenient and Unnecessary? Regulations in the U.S. Taxi Industry

    Directory of Open Access Journals (Sweden)

    Johnson Colton

    2017-12-01

    Full Text Available A Certificate of Public Convenience and Necessity (CPCN is a common requirement for a new business owner in services such as utilities, communications, healthcare, and transportation. However, studies have called into question the effectiveness and purpose of these laws when applied in certain industries. This study chronicles the development of and justifications provided for the enactment of CPCN laws. It then empirically tests the effectiveness of these laws in the taxi industry. This paper finds no evidence that the CPCN laws in the taxi industry are meeting their objectives. Some evidence suggests that CPCN laws achieve the opposite of their intention.

  7. Constitutive expression of the xylanase inhibitor TAXI-III delays Fusarium head blight symptoms in durum wheat transgenic plants.

    Science.gov (United States)

    Moscetti, Ilaria; Tundo, Silvio; Janni, Michela; Sella, Luca; Gazzetti, Katia; Tauzin, Alexandra; Giardina, Thierry; Masci, Stefania; Favaron, Francesco; D'Ovidio, Renato

    2013-12-01

    Cereals contain xylanase inhibitor (XI) proteins which inhibit microbial xylanases and are considered part of the defense mechanisms to counteract microbial pathogens. Nevertheless, in planta evidence for this role has not been reported yet. Therefore, we produced a number of transgenic plants constitutively overexpressing TAXI-III, a member of the TAXI type XI that is induced by pathogen infection. Results showed that TAXI-III endows the transgenic wheat with new inhibition capacities. We also showed that TAXI-III is correctly secreted into the apoplast and possesses the expected inhibition parameters against microbial xylanases. The new inhibition properties of the transgenic plants correlate with a significant delay of Fusarium head blight disease symptoms caused by Fusarium graminearum but do not significantly influence leaf spot symptoms caused by Bipolaris sorokiniana. We showed that this contrasting result can be due to the different capacity of TAXI-III to inhibit the xylanase activity of these two fungal pathogens. These results provide, for the first time, clear evidence in planta that XI are involved in plant defense against fungal pathogens and show the potential to manipulate TAXI-III accumulation to improve wheat resistance against F. graminearum.

  8. Association of Some Environmental Factors with Breath Carbon Monoxide Levels of Some Taxi Drivers in Ankara

    Directory of Open Access Journals (Sweden)

    Oguz Baran

    2010-12-01

    Full Text Available AIM: Taxi drivers are among the occupational groups with the highest smoking prevalence and exposure to carbon monoxide (CO. This study aimed to measure breath CO levels of some taxi drivers working in Ankara and to find out some associated factors (if any. METHOD: The descriptive study was carried out with 173 taxi drivers from 14 different taxi stations in the center of Ankara. Data was collected by face to face interviews with a standart questionnaire, while breath CO was measured by a Pi-CO Smokerlyser. Descriptive statistics were used to summarize data, whereas chi-square, independant samples t-test and One-Way ANOVA were used to compare groups by SPSS 15.0 statistical package programme. RESULTS: In the study, all of the taxi drivers (n=173 were male with a mean age of 39.2±9.6 years. Of the drivers, 58.4% were current smokers, whereas 75.1% were exposed to enviromental tobacco smoke. The frequency of indoor smoking in the taxi stations, taxis and drivers’ homes were 48.0%, 45.1%, and 59.0%, respectively. The mean breath CO level of the drivers was 16.9±12.8 ppm. CO level was positively associated with the current smoking status, total years of smoking, number of cigarettes smoked per day and passive exposure to tobacco smoke, whereas the association was negative with the elapsed time from the last cigarette smoked (p0.05. CONCLUSION: Results of the study provide evidence in support of the previous literature that smoking is one of the most important sources of carbonmonoxide. Interventions such as awareness raising trainings, referral of smokers willing to quit smoking to smoking cessation centers and screening programmes for smoking related diseases are needed to be implemented in collaboration with the relevant drivers’ associations. [TAF Prev Med Bull 2010; 9(6.000: 591-596

  9. Distribution of Total Volatile Organic Compounds at taxi drivers in Tehran

    Directory of Open Access Journals (Sweden)

    Seyyed Mohammad Javad Golhosseini

    2015-06-01

    Full Text Available Air pollution is currently the most serious environmental health threat worldwide. Volatile Organic Compounds (VOC are considered as the main effective factors in causing air pollution. Vehicles are among the major sources which emit these compounds, so it seems that automobiles’ microenvironment is one of the places where people are exposed to high concentration of VOC. Evaluating the exposure amount of Total Volatile Organic Compounds (TVOC can indeed be used as an indicator to estimate the amount of exposure to every individual VOC. This study was conducted on the concentration of TVOC inside Tehran taxies for a period of one year. For this purpose, a real time instrument equipped with photo-ionization detector (PID was used. Consequently, the highest and the lowest measured TVOC in taxies equaled 3.33 ppm and 0.72 ppm, respectively. In addition, the arithmetic mean of TVOC concentration was 1.77±0.53 ppm inside the examined taxies. In this study, the parameters like measurement time, climate and vehicle conditions were found to have significant effect on the amount of exposure to TVOC.

  10. Minibus taxi drivers’ sexual beliefs and practices associated with HIV infection and AIDS in KwaZulu- Natal, South Africa

    Directory of Open Access Journals (Sweden)

    Busisiwe Ncama

    2013-01-01

    Full Text Available Risky sexual behaviours in South Africa are a major contributing factor to the spread of HIV infection and AIDS. HIV infection amongst minibus taxi drivers is a concern, because these people belong to an occupational group that exhibits risky behaviours due to the demands of their work. Given the high vulnerability of minibus taxi drivers, exploring the sexual beliefs and health-related sexual practices of this group will assist in planning targeted interventions.The objectives of this study were to assess the level of knowledge, beliefs and practices regarding HIV infection and AIDS amongst minibus taxi drivers. An exploratory descriptive study was conducted using a pre-tested questionnaire to explore and describe sexual beliefs and practices associated with HIV infection and AIDS in a convenience sample of 175 minibus taxi drivers. Permission to undertake the study was obtained from the KwaZulu-Natal Taxi Alliance and individuals who participated in the study. Data analysis were analysed using the Statistical Package for Social Sciences 13.0. The study revealed that minibus taxi drivers are one of the high- risk groups in the spread of HIV infection and AIDS; they lack necessary education and need attention in relation to control and prevention of the spread of HIV and AIDS. Multiple sexual partners are relatively common amongst the minibus taxi drivers. Violence against women and even forceful sexual intercourse in the belief that women should tolerate it to keep the family together was reported. There is a need for intervention programmes with a focus on minibus taxi drivers and similar high-risk groups. Prevention activities should incorporate the distribution of condoms amongst this group and HIV prevention educational programmes, as well as creating mechanisms for accessing circumcision by the minibus taxi drivers.

  11. Digital collaborative consumption and social issues: The clash of taxi and Uber driver in Surabaya and Taipei

    Directory of Open Access Journals (Sweden)

    Kholifatus Saadah

    2017-12-01

    Full Text Available Since the occurrence of application-based taxi, phenomenon and resistance have emerged in metropolitan cities around the world. One of the main issues highlighted is digital collaborative consumption which emerges as the consequences of globalization. As an interpretive case study research, this paper aims to analyze the use of Uber as an alternative to public transportation in Taipei and Surabaya. Authors discuss the issue by comparing the reaction toward the occurrence of Uber and Taipei and Surabaya. Authors apply the theory from Hegre, Gissinger, & Gledtisch (2002 about globalization and social conflict to explain social issues as the consequences of digital collaborative consumption as the new consumption model. According to the theory, globalization creates a deprivation which makes the struggle to access source of capital become more intense. Poverty is the main generator of radical action and violence. Analyzing the phenomena of Uber usage and the resistance from traditional taxi businessmen in Taipei and Surabaya, the authors argue that globalization reflected on digital collaborative consumption could lead to social unrest for parties who cannot adapt to the changes in economic practice. As shown by many cases of app-based rejection taxi in public places such as airport, train station and bus station; the traditionalists show resistance towards globalization and the economic shift of public transportation business model.

  12. Complexities’ day-to-day dynamic evolution analysis and prediction for a Didi taxi trip network based on complex network theory

    Science.gov (United States)

    Zhang, Lin; Lu, Jian; Zhou, Jialin; Zhu, Jinqing; Li, Yunxuan; Wan, Qian

    2018-03-01

    Didi Dache is the most popular taxi order mobile app in China, which provides online taxi-hailing service. The obtained big database from this app could be used to analyze the complexities’ day-to-day dynamic evolution of Didi taxi trip network (DTTN) from the level of complex network dynamics. First, this paper proposes the data cleaning and modeling methods for expressing Nanjing’s DTTN as a complex network. Second, the three consecutive weeks’ data are cleaned to establish 21 DTTNs based on the proposed big data processing technology. Then, multiple topology measures that characterize the complexities’ day-to-day dynamic evolution of these networks are provided. Third, these measures of 21 DTTNs are calculated and subsequently explained with actual implications. They are used as a training set for modeling the BP neural network which is designed for predicting DTTN complexities evolution. Finally, the reliability of the designed BP neural network is verified by comparing with the actual data and the results obtained from ARIMA method simultaneously. Because network complexities are the basis for modeling cascading failures and conducting link prediction in complex system, this proposed research framework not only provides a novel perspective for analyzing DTTN from the level of system aggregated behavior, but can also be used to improve the DTTN management level.

  13. Minibus taxi drivers’ sexual beliefs and practices associated with HIV infection and AIDS in KwaZulu- Natal, South Africa

    Directory of Open Access Journals (Sweden)

    Busisiwe Ncama

    2013-01-01

    The objectives of this study were to assess the level of knowledge, beliefs and practices regarding HIV infection and AIDS amongst minibus taxi drivers. An exploratory descriptive study was conducted using a pre-tested questionnaire to explore and describe sexual beliefs and practices associated with HIV infection and AIDS in a convenience sample of 175 minibus taxi drivers. Permission to undertake the study was obtained from the KwaZulu-Natal Taxi Alliance and individuals who participated in the study. Data analysis were analysed using the Statistical Package for Social Sciences 13.0. The study revealed that minibus taxi drivers are one of the high- risk groups in the spread of HIV infection and AIDS; they lack necessary education and need attention in relation to control and prevention of the spread of HIV and AIDS. Multiple sexual partners are relatively common amongst the minibus taxi drivers. Violence against women and even forceful sexual intercourse in the belief that women should tolerate it to keep the family together was reported. There is a need for intervention programmes with a focus on minibus taxi drivers and similar high-risk groups. Prevention activities should incorporate the distribution of condoms amongst this group and HIV prevention educational programmes, as well as creating mechanisms for accessing circumcision by the minibus taxi drivers.

  14. Les aspects matériels de la taxis byzantine The material aspects of the Byzantine taxis

    Directory of Open Access Journals (Sweden)

    Marie‑France Auzépy

    2008-06-01

    Full Text Available La taxis grecque – correspondant exact de l’ordo latin – est un aspect essentiel de la civilisation byzantine : elle organise cette société de manière à ce que celle-ci soit un reflet aussi exact que possible de la société céleste, décrite en particulier par Denys l’Aréopagite. La taxis est donc à la fois précise et contraignante et nous a été transmise dans des livres décrivant le protocole : le De Cerimoniis au Xe siècle, le Traité du pseudo-Kodinos au XIVe siècle. Au cours de cérémonies où tous les aspects matériels – l’habit, la couronne, le trône, les acclamations à la gloire de l’empereur, l’orgue qui les accompagne, les gestes accomplis par l’empereur comme par ceux qui l’entourent – ont un sens, l’Empire byzantin affirme ainsi son équilibre et sa qualité de peuple élu. Jusqu’en 1204, les autres nations ont jalousé la qualité que s’était octroyée l’Empire romain d’Orient : celle d’image de la cour céleste, qui est figurée dans le cérémonial. Cette jalousie a pris d’autres formes après 1453, et l’on s’intéressera aux souverains européens qui, tel Louis XIV, ont voulu faire figure d’héritiers de l’empire défunt et relever ses cérémonies.The Greek taxis(order– the exact equivalent of the Latin ordo – is an essential aspect of Byzantine civilization: it organized society in such a way that it would reflect the celestial society as closely as possible, as has been described by Dionysius the Areopagite. The taxis is therefore both precise and restrictive and has been passed down to us through writings describing the protocol: the De Cerimoniis in the tenth century and the treatise of Pseudo-Kodinos in the fourteenth century. Through ceremonies in which all the material aspects have a meaning – the dress, the crown, the throne, the proclaiming of the glory of the emperor, the accompanying organ, the gestures of the emperor and of those around

  15. An open-data approach for quantifying the potential of taxi ridesharing

    DEFF Research Database (Denmark)

    Barann, Benjamin; Beverungen, Daniel; Müller, Oliver

    2017-01-01

    greenhouse gas emissions. We develop a one-to-one TRS approach that matches rides with similar start and end points. We evaluate our approach by analyzing an open dataset of > 5 million taxi trajectories in New York City. Our empirical analysis reveals that the proposed approach matches up to 48.34% of all...... taxi rides, saving 2,892,036 km of travel distance, 231,362.89 l of gas, and 532,134.64 kg of CO2 emissions per week. Compared to many-to-many TRS approaches, our approach is competitive, simpler to implement and operate, and poses less rigid assumptions on data availability and customer acceptance....

  16. The influence of fixed-route taxi on road accidents and air pollution

    Directory of Open Access Journals (Sweden)

    V. Fedotov

    2006-03-01

    Full Text Available The development of market economy in Russia expands the need for movement of groups of people of large mega cities on time to a place at simultaneous reduction of the number of groups with identical purposes. Therefore for many cities a wide use of fixed-route taxis the service of passengers at a constant increase of the numbers of routes and the numbers of transport units was characteristic. At the certain intensity of the movement of fixed-route taxis on separate sites of city highways the transport stream and the changing quality of environment raises the risk of road accident and becomes ecologically unsafe. The results of the estimation of the negative influence of fixed-route taxis in comparison with other categories of vehicles are presented. The research was made on city highways running through the zones with a greater number of cultural and community places, shopping centers and administrative establishments. Perspective ways of the increase of traffic safety and the decrease of concentration of harmful emissions are offered.

  17. Health Status, Intention to Seek Health Examination, and Participation in Health Education Among Taxi Drivers in Jinan, China

    Science.gov (United States)

    Yang, Yan; Fan, Xiao-sheng; Tian, Cui-huan; Zhang, Wei; Li, Jie; Li, Shu-qing

    2014-01-01

    Background: Taxi drivers are exposed to various risk factors such as work overload, stress, an irregular diet, and a sedentary lifestyle, which make these individuals vulnerable to many diseases. This study was designed to assess the health status of this occupational group. Objectives: The objective was to explore the health status, the intention to seek health examination, and participation in health education among taxi drivers in Jinan, China. Patients and Methods: The sample-size was determined scientifically. The systematic sampling procedure was used for selecting the sample. Four hundred taxi drivers were randomly selected from several taxi companies in Jinan. In total, 396 valid questionnaires (from 370 males and 26 females) were returned. Health status, intention to seek health examination, and participation in health education were assessed by a self-designed questionnaire. Other personal information including sex, age, ethnicity, marital status, years of employment as a taxi driver, education level, and habits were also collected. Results: This survey revealed that 54.8% of taxi drivers reported illness in the last two weeks and 44.7% of participants reported chronic diseases. The prevalence rates of hypertension, diabetes mellitus, gastroenteritis, arthritis, and heart disease were 18.2%, 8.8%, 26%, 18.4%, and 4.8% of questioned taxi drivers, respectively. Significant self-reported symptoms included fatigue, waist and back pain, headache, dyspepsia, and dry throat affecting 49.7%, 26.2%, 23.5%, 26%, and 27% of participants, respectively. In total, 90.1% of subjects thought that it was necessary to receive a regular health examination. Only 17.9% of subjects had been given information about health education, and significantly, more than 87% of subjects who had been given information about health education reported that the information had been helpful. Conclusions: Taxi drivers’ health was poor in our survey. Thus, using health education interventions

  18. A Feasibility Test on Adopting Electric Vehicles to Serve as Taxis in Daejeon Metropolitan City of South Korea

    Directory of Open Access Journals (Sweden)

    Seoin Baek

    2016-09-01

    Full Text Available For realizing sustainable development, EV (Electric Vehicle is currently considered as one of the most promising alternative due to its cleanness and inexhaustibility. However, the development and dissemination of EV has stagnated because it faces major constraints such as battery performance and an excessively long charging time. Thus, this study examined the feasibility of using EVs as taxis by analyzing real data from a pilot project in Daejeon, a metropolitan city in South Korea for proposing the effective way to adopt EV. To reflect reality and improve accuracy, we adopted scenarios and assumptions based on in-depth interviews with groups of experts. The resulting initial benefit-to-cost (B/C ratio for EV taxis is approximately 0.4, which is quite low compared to 0.7 for traditional taxis. However, after incorporating some further assumptions into the calculation, the B/C ratio shifts to approximately 0.7, which is more appropriate for EV adoption. For this improvement to be achieved, the dissemination of a charging infrastructure, improvement of the business model and policy support is strongly needed. Limitations to this work and potential areas for future study are also fully discussed.

  19. Comparison between internal combustion engines and simulated electrical propulsion of taxis; Vergleich zwischen verbrennungsmotorischem und simuliertem elektrischen Antrieb von Taxis

    Energy Technology Data Exchange (ETDEWEB)

    Wallner, Stefan [Stefan Wallner Energietechnik, Unterhaching (Germany); Thym, Jochen

    2011-03-15

    The term 'triumphal procession of electromobility' produces an enormous expectation at the end users side, but intensive development work has still to be done. The transition from today's vehicles towards electric propulsion is not to be expected to take place overnight but will start with slot applications. Energietechnik Wallner has analysed the potential of taxis. (orig.)

  20. THE ROUTE DETERMINATION OF FILING A TAXI TO THE CUSTOMER IN TERMS OF FUNCTIONING OF THE AUTOMATED CONTROL SYSTEM

    Directory of Open Access Journals (Sweden)

    Yu. O. Davidich

    2008-03-01

    Full Text Available The issues of overall performance increase of taxi transport due to improvement of automated system of dispatching management by its technological processes are considered. The route of taxi submission to a customer is offered to be determined by a criterion of minimum time. To solve the given task the taxi submission route determination technique is developed. It will promote the reduction of passengers’ waiting time and the decrease in operational expenses of a carrier.

  1. Automation of orders in taxi service

    OpenAIRE

    Simčič, Matej

    2012-01-01

    Automation is rapidly growing in the last years. The advantages it brings are cost reduction, faster and better performance of tasks that would be otherwise done by humas. It began in the manufacturing industry and later expanded to other sectors. Today's technology allows the implementation of automation in a wide range of areas. The thesis deals with the implementation of a system that allows automated ordering of a taxi. The system consists of four components. They are two mobile app...

  2. 76 FR 65769 - Application of Friendship Airways, Inc. d/b/a Yellow Air Taxi for Commuter Authority

    Science.gov (United States)

    2011-10-24

    ... DEPARTMENT OF TRANSPORTATION Office of the Secretary Application of Friendship Airways, Inc. d/b/a Yellow Air Taxi for Commuter Authority AGENCY: Department of Transportation. ACTION: Notice of Order to... issued to Friendship Airways, Inc. d/b/a Yellow Air Taxi and deny its application to resume commuter...

  3. A hybrid life cycle and multi-criteria decision analysis approach for identifying sustainable development strategies of Beijing's taxi fleet

    International Nuclear Information System (INIS)

    Cai, Yanpeng; Applegate, Scott; Yue, Wencong; Cai, Jianying; Wang, Xuan; Liu, Gengyuan; Li, Chunhui

    2017-01-01

    To identify and evaluate sustainable strategies of taxi fleet in Beijing in terms of economic, policy, and environmental implications, a hybrid approach was developed through incorporating multi-criteria decision analysis (MCDA) methods within a general life-cycle analysis (LCA) framework. The approach can (a) help comprehensive evaluate environmental impacts of multiple types of vehicles, (b) facilitate analysis of environmental, economic and policy features of such vehicles, and (c) identify desirable taxi fleet development strategies for the city. The developed approach represented an improvement of the decision-making capability for taxi implementation based on multiple available technologies and their performance that can be specifically tailored to Beijing. The results demonstrated that the proposed approach could comprehensively reflect multiple implications of strategies for the taxi fleet in Beijing to reduce air pollution in the city. The results also indicated that the electric vehicle powered with the year 2020 electricity projections would be the ideal solution, outranking the other alternatives. The conventional vehicle ranked the lowest among the alternatives. The plug-in hybrid vehicle powered by 2020 electricity projects ranked the third, followed by the plug-in hybrid vehicle ranking the fourth, and the hybrid vehicle ranking the fifth. - Highlights: • An hybrid approach was proposed for evaluating sustainable strategies of Beijing's taxi fleet. • This approach was based on the combination of multi-criteria decision analysis methods and life-cycle assessment. • Environmental, economic and policy performances of multiple strategies were compared. • Detailed responses of taxi drivers and local residents were interviewed. • The electric vehicle would be the ideal solution for Beijing Taxi fleet.

  4. Integration of electric vehiclesin cooper atives taxi ambato. Ecuador

    Directory of Open Access Journals (Sweden)

    Mery Esperanza Ruiz Guajala

    2015-11-01

    Full Text Available The transition from combustion vehicles towards a new electrical system friendly to the environment, is a decision to be taken by carrier based on cost-benefit analysis which generates buying it, and contribute to society not only for the service they provide, but to prevent air pollution we breathe, and if we add the future energy supply, since the Ecuadorian State in 2016 will provide the whole country of this important resource. The study focuses on two parts: the first on surveys of taxi owners to describe their perception of the integration of electric vehicles, and the second in determining the economic and financial feasibility of acquiring the vehicle Nissan Leaf by the member of the cooperative taxi. The most important conclusion is that the carriers are willing to buy an electric vehicle to mitigate the emission of toxic gases, and that its decision would save 50% in annual operating costs of your vehicle.

  5. The Effect of Working Conditions to the Health Status in Taxi and Bus Drivers in Canakkale, Turkey; Community Based Study

    Directory of Open Access Journals (Sweden)

    Aysegul Uludag

    2016-04-01

    Full Text Available Aim: The growing taxi and bus driver workforce is at risk for poor health status, obesity, hypertension, metabolic syndrome and with increased risk for cardiovascular disease. We aimed to determine the relationship between working conditions and health status in taxi and bus drivers. Material and Method: This study is a descriptive study. The population of the study was taxi and bus drivers in central of Canakkale. There were total 250 taxi and bus drivers who registered in The Chamber of Canakkale Drivers and Vehicle. We reached the 70 taxi drivers and 93 bus drivers. The participants were visited at their workplace. We performed the questionnaire that include the socio-demografic features, habits, the working conditions. We evaluated the blood pressure, waist-hip measurements and capillary blood glucose at any time. Results: Total of the 163 men drivers were enrolled the study. Nine (12.9% taxi drivers and 6 (6.5% bus drivers were hipertensive, and 1 taxi driver and 2 bus drivers with random capillary blood glucose levels higher than 200 mg. The prevalence of hypertension was 9.2%, diabetes mellitus was 1.8, obesity was 49.4%. Discussion: Drivers have many risk factors for CVD like stress and immobility. In our study, the socio-demografic and working conditions are limited for explaining the risk for hipertension, diabetes mellitus and obesity in drivers in Canakkale. These study have to be done in metropolitan cities. In this aspect, the drivers can be evaluated in their own living spaces and working conditions.

  6. The Aircraft Electric Taxi System: A Qualitative Multi Case Study

    Science.gov (United States)

    Johnson, Thomas Frank

    The problem this research addresses is the airline industry, and the seemingly unwillingness attitude towards adopting ways to taxi aircraft without utilizing thrust from the main engines. The purpose of the study was to get a better understanding of the decision-making process of airline executives, in respect to investing in cost saving technology. A qualitative research method is used from personal interviews with 24 airline executives from two major U.S. airlines, related industry journal articles, and aircraft performance data. The following three research questions are addressed. RQ1. Does the cost of jet fuel influence airline executives' decision of adopting the aircraft electric taxi system technology? RQ2 Does the measurable payback period for a return on investment influence airline executives' decision of adopting ETS technology? RQ3. Does the amount of government assistance influence airline executives' decision of adopting ETS technology? A multi case research study design is used with a triangulation technique. The participant perceptions indicate the need to reduce operating costs, they have concerns about investment risk, and they are in favor of future government sponsored performance improvement projects. Based on the framework, findings and implications of this study, a future research paper could focus on the positive environmental effects of the ETS application. A study could be conducted on current airport area air quality and the effects that aircraft main engine thrust taxiing has on the surrounding air quality.

  7. A feasibility study of mapping light-absorbing carbon using a taxi fleet as a mobile platform

    Directory of Open Access Journals (Sweden)

    Patricia Krecl

    2014-04-01

    Full Text Available Carbon-containing particles are associated with adverse health effects, and their light-absorbing fractions were recently estimated to be the second largest contributor to global warming after carbon dioxide. Knowledge on the spatiotemporal variability of light-absorbing carbon (LAC particles in urban areas is relevant for air quality management and to better diagnose the population exposure to these particles. This work reports on the first mobile LAC mass concentrations (MLAC measured on-board four taxis in the Stockholm metropolitan area in November 2011. On average, concentrations were higher and more variable during daytime (median of 1.9 µg m−3 and median absolute deviation of 2.3 µg m−3. Night-time (21:00–05:00 measurements were very similar for all road types and also compared to levels monitored at an urban background fixed site (median of 0.9 µg m−3. We observed a large intra-urban variability in concentrations, with maxima levels inside road tunnels (median and 95th percentile of 7.5 and 40.1 µg m−3, respectively. Highways presented the second ranked concentrations (median and 95th percentile of 3.2 and 9.7 µg m−3, respectively associated with highest vehicle speed (median of 65 km h−1, traffic rates (median of 62 000 vehicles day−1 and 1500 vehicles h−1 and diesel vehicles share (7–10% when compared to main roads, canyon streets, and local roads. Multiple regression modelling identified hourly traffic rate and MLAC concentration measured at an urban background site as the best predictors of on-road concentrations, but explained only 25% of the observed variability. This feasibility study proved to be a time- and cost-effective approach to map out ambient MLAC concentrations in Stockholm and more research is required to represent the distribution in other periods of the year. Simultaneous monitoring of other pollutants, closely correlated to MLAC levels in traffic-polluted environments, and including video

  8. Outsourcing of Defense Supply Center, Columbus, Bus and Taxi Service Operations

    National Research Council Canada - National Science Library

    Granetto, Paul

    1999-01-01

    Introduction. We performed the audit in response to allegations to the Defense Hotline that the Defense Supply Center, Columbus, outsourcing study for bus and taxi service operations was based on incorrect methodology...

  9. Factor Analysis of Passenger Cars Using as a Taxi

    Directory of Open Access Journals (Sweden)

    Deriugin O.V.

    2016-05-01

    Full Text Available A procedure to select passenger cars has been proposed. The procedure helps substantiate choice of effective transportation means in accordance with taxi class to meet consumption requirements of those taking part in transportation process from the viewpoint of comfort, safety, and minimum expenditures in the context of such transportation type.

  10. Development of ATC Tower Systems: Electronic Flight Strip System at LKPR and the Implementation of TAXI Milestone to SUM

    Directory of Open Access Journals (Sweden)

    Pavel Černý

    2016-10-01

    Full Text Available This article describes the Electronic Flight Strip System used at Václav Havel Airport Prague and presents the results of an analysis of the clearance input from ATCOs. The outcomes indicate that various clearances are frequently issued together in a common time frame, usually depending on the traffic flow structure. The focus then moves towards the implementation of the TAXI milestone into the Start-Up Manager. The used statistic methods indicate that the amount of TTOT recalculations after AOBT decreases, but not significantly. However, the accuracy of TTOT after TAXI clearance is considerably better. The mean and most common deviation of ATOT from TTOT after the implementation of TAXI milestone is -1 minute. The results are challenged and confirmed by a further analysis of the TTOT-ATOT difference regarding individual stand/RWY pairs. The results may be used to adjust the assumed taxi times.

  11. Optimal Fare, Vacancy Rate, and Subsidies under Log-Linear Demand with the Consideration of Externalities for a Cruising Taxi Market

    Directory of Open Access Journals (Sweden)

    Chun-Hsiao Chu

    2017-01-01

    Full Text Available Externality is an important issue for formulating the regulation policy of a taxi market. However, this issue is rarely taken into account in the current policy-making process, and it has not been adequately explored in prior research. This study extends the model proposed by Chang and Chu in 2009 with the aim of exploring the effect of externality on the optimization of the regulation policy of a cruising taxi market. A closed-form solution for optimizing the fare, vacancy rate, and subsidy of the market is derived. The results show that when the externality of taxi trips is taken into consideration, the optimal vacancy rate should be lower and the subsidy should be higher than they are under current conditions where externality is not considered. The results of the sensitivity analysis on the occupied and vacant distance indicate that the relation of the vacant distance to the marginal external cost is more sensitive than the occupied distance. The result of the sensitivity analysis on the subsidy shows the existence of a negative relationship between the marginal external cost and the optimal subsidy.

  12. Fuel Consumption and Emissions from Airport Taxi Operations

    Science.gov (United States)

    Jung, Yoon

    2010-01-01

    Developed a method to calculate fuel consumption and emissions of phases of taxi operations. Results at DFW showed that up to 18% of fuel can be saved by eliminating stop-and-go situations. Developed an energy efficient and environmentally friendly surface concept: Spot and Runway Departure Advisory (SARDA) tool. The SARDA tool has been identified as a potential candidate for a technology transfer to the FAA.

  13. Video event data recording of a taxi driver used for diagnosis of epilepsy

    Directory of Open Access Journals (Sweden)

    Kotaro Sakurai

    2014-01-01

    Full Text Available A video event data recorder (VEDR in a motor vehicle records images before and after a traffic accident. This report describes a taxi driver whose seizures were recorded by VEDR, which was extremely useful for the diagnosis of epilepsy. The patient was a 63-year-old right-handed Japanese male taxi driver. He collided with a streetlight. Two years prior to this incident, he raced an engine for a long time while parked. The VEDR enabled confirmation that the accidents depended on an epileptic seizure and he was diagnosed with symptomatic localization-related epilepsy. The VEDR is useful not only for traffic accident evidence; it might also contribute to a driver's health care and road safety.

  14. [Comparative life cycle environmental assessment between electric taxi and gasoline taxi in Beijing].

    Science.gov (United States)

    Shi, Xiao-Qing; Sun, Zhao-Xin; Li, Xiao-Nuo; Li, Jin-Xiang; Yang, Jian-Xin

    2015-03-01

    Tailpipe emission of internal combustion engine vehicle (ICEV) is one of the main sources leading to atmospheric environmental problems such as haze. Substituting electric vehicles for conventional gasoline vehicles is an important solution for reducing urban air pollution. In 2011, as a pilot city of electric vehicle, Beijing launched a promotion plan of electric vehicle. In order to compare the environmental impacts between Midi electric vehicle (Midi EV) and Hyundai gasoline taxi (ICEV), this study created an inventory with local data and well-reasoned assumptions, and contributed a life cycle assessment (LCA) model with GaBi4.4 software and comparative life cycle environmental assessment by Life cycle impact analysis models of CML2001(Problem oriented) and EI99 (Damage oriented), which included the environmental impacts of full life cycle, manufacture phase, use phase and end of life. The sensitivity analysis of lifetime mileage and power structure was also provided. The results indicated that the full life cycle environmental impact of Midi EV was smaller than Hyundai ICEV, which was mainly due to the lower fossil fuel consumption. On the contrary, Midi EV exhibited the potential of increasing the environmental impacts of ecosystem quality influence and Human health influence. By CML2001 model, the results indicated that Midi EV might decrease the impact of Abiotic Depletion Potential, Global Warming Potential, Ozone Layer Depletion Potential and so on. However, in the production phase, the impact of Abiotic Depletion Potential, Acidification Potential, Eutrophication Potential, Global Warming Potential, Photochemical Ozone Creation Potential, Ozone Layer Depletion Potential, Marine Aquatic Ecotoxicity Potential, Terrestric Ecotoxicity Potential, Human Toxicity Potential of Midi EV were increased relative to Hyundai ICEV because of emissions impacts from its power system especially the battery production. Besides, in the use phase, electricity production was

  15. Health status, job stress and work-related injury among Los Angeles taxi drivers.

    Science.gov (United States)

    Wang, Pin-Chieh; Delp, Linda

    2014-01-01

    Taxi drivers work long hours for low wages and report hypertension, weight gain, and musculoskeletal pain associated with the sedentary nature of their job, stressful working conditions, and poor dietary habits. They also experience a high work-related fatality rate. The objective of this study is to examine the association of taxi drivers' health status and level of job stress with work-related injury and determine if a potential interaction exists. A survey of 309 Los Angeles taxi drivers provides basic data on health status, job stress, and work-related injuries. We further analyzed the data using a Modified Poisson regression approach with a robust error variance to estimate the relative risk (RR) and the 95% confidence intervals (CI) of work-related injuries. Focus group results supplemented and helped interpret the quantitative data. The joint effect of good health and low job stress was associated with a large reduction in the incidence of injuries, consistent with the hypothesis that health status and stress levels modify each other on the risk of work-related injury. These results suggest that the combination of stress reduction and health management programs together with changes in the stressful conditions of the job may provide targeted avenues to prevent injuries.

  16. THE AUTOMATIC SYSTEM’S MODEL OF DECISION-MAKING SUPPORT FOR DISPATCHING CONTROL OF THE CITY PASSENGER TRAFFIC

    Directory of Open Access Journals (Sweden)

    V. A. Lakhno

    2016-04-01

    Full Text Available Purpose. This scientific work considers the further development of mathematical models and algorithms for automatic decision support for dispatching management of the city passenger traffic. Methodology. Systems of dispatching management for the city passenger transport are to provide the carrying out of the routes according schedules with minimal deviations from the planned ones through the using of appropriate control actions. The systems’ algorithm focuses on the selection of control actions that compensate the disturbances. It is proposed to use the index of the waiting time minimum for passengers of buses and taxis at stops as a criterion for evaluating of dispatching control systems work. Findings. Based on the conducted analysis of the research within the existing theory of traffic flow of vehicles, it was proposed the model for the system of dispatching management for urban passenger moving units considering the effect of the most important stochastic factors on the schedule of buses and taxis movement in large cities. The obtained system of equations that models the parameter of movement on the bus routes allows you to assess quickly the influence of disturbing effects on the service quality indicators of passengers and, if necessary, to draw up the optimal schedule. Originality. The authors propose a new model for decision support of dispatching management for the city passenger transport. They take into account the effect of the most important stochastic factors, such as the overflowing buses and taxis, their descent from the lines, delays, deviations from the speed limit on the route, etc., on indicators of service quality, as well as optimizing the schedule. Practical value. The results allow to improve approaches to building models using in the systems of dispatching management of urban bus routes, as well as to improve the selection of control actions for similar systems in large cities of Ukraine.

  17. Assessing Patient bypass Behavior Using Taxi Trip Origin–Destination (OD Data

    Directory of Open Access Journals (Sweden)

    Gege Yang

    2016-09-01

    Full Text Available Many patients prefer to use the best hospitals even if there are one or more other hospitals closer to their homes; this behavior is called “hospital bypass behavior”. Because this behavior can be problematic in urban areas, it is important that it be reduced. In this paper, the taxi GPS data of Beijing and Suzhou were used to measure hospital bypass behavior. The “bypass behavior index” (BBI represents the bypass behavior for each hospital. The results indicated that the mean hospital bypass trip distance value ranges from 5.988 km to 9.754 km in Beijing and from 4.168 km to 10.283 km in Suzhou. In general, the bypass shares of both areas show a gradually increasing trend. The following hospitals exhibited significant patient bypass behavior: the 301 Hospital, Beijing Children’s Hospital, the Second Affiliated Hospital of Soochow University and the Suzhou Hospital of Traditional Chinese Medicine. The hospitals’ reputation, transport accessibility and spatial distribution were found to be the main factors affecting patient bypass behavior. Although the hospital bypass phenomena generally appeared to be more pronounced in Beijing, the bypass trip distances between hospitals were found to be more significant in Suzhou.

  18. Urban poverty and informal motorcycle transport services in a Nigerian intermediate settlement: a synthesis of operative motives and satisfaction

    Directory of Open Access Journals (Sweden)

    Abubakar Zakariyya Al-Hasan

    2015-01-01

    Full Text Available The paper aims at examining operations motives and satisfaction in motorcycle taxi operators in Auchi. Primary data were sourced using structured questionnaires. Of the 148 questionnaires administered, 135 were found analysable. SPSS software version 17.0 was used for data analysis. The frequency distribution result of the demographic information of the respondents revealed that males, aged 21–30 year (58%, are predominantly involved in the operation. The education level of the majority of operators was in the secondary cohort (62.2%. Among operators, 56% operate motorcycle taxis for self-employment, whilst 34.1% was for augmenting income. A test of hypothesis result suggested that operator satisfaction based on the motive behind operation is statistically significant at 1%. The findings also strengthen previous studies. In terms of sustainability, informal motorcycle taxis are considered by the study to be unrealistic given the efficient transport system and enabling economic situation. Moreover, their operation impacts negatively on the environment, health, social and human capital development. Government and transport policy-makers should pursue efficient integrated modal transport system. Poverty alleviation machinery by government should explore viable initiatives that will engage the urban poor, especially youths, to divest their massive involvements in motorcycle taxi operation in Nigeria.

  19. Understanding complex urban systems integrating multidisciplinary data in urban models

    CERN Document Server

    Gebetsroither-Geringer, Ernst; Atun, Funda; Werner, Liss

    2016-01-01

    This book is devoted to the modeling and understanding of complex urban systems. This second volume of Understanding Complex Urban Systems focuses on the challenges of the modeling tools, concerning, e.g., the quality and quantity of data and the selection of an appropriate modeling approach. It is meant to support urban decision-makers—including municipal politicians, spatial planners, and citizen groups—in choosing an appropriate modeling approach for their particular modeling requirements. The contributors to this volume are from different disciplines, but all share the same goal: optimizing the representation of complex urban systems. They present and discuss a variety of approaches for dealing with data-availability problems and finding appropriate modeling approaches—and not only in terms of computer modeling. The selection of articles featured in this volume reflect a broad variety of new and established modeling approaches such as: - An argument for using Big Data methods in conjunction with Age...

  20. Reduction of particle emissions from light duty vehicles and from taxies; Reduktion af partikelelemissioner fra varebiler og taxier

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, Johan; Henriques, M.; Weibel, T.G. [TetraPlan A/S (Denmark)

    2006-11-03

    This project, 'Reduction of particle emissions from light duty vehicles and from taxies', analyses different strategies to reduce the particle emission, their effect for particle emissions, and the resulting cost for the society and for the companies. The project describes the EU regulation of emissions, the possibilities of reducing the emissions via special requirements in environmental zones and the Danish taxation of light duty vehicles. Further, the project includes interviews with owners of light duty vehicles and taxies and also with Danish producers of particle filters. The strategies analysed in the scenarios include: 1) Promotion of particle filters; 2) Shift from diesel to gasoline and; 3) Downsizing. The effects for particle emissions and for mortality are described. Further, the costs and benefits for the society and the cost for the companies are evaluated. The effects of the scenarios are analysed, both for initiatives implemented at a national level and for implementation in an environmental zone in the municipality of Copenhagen. The main results are that the socioeconomic benefits in the year 2012 are greater than the costs, if taxis and light duty vehicles have filters installed and if they are driving in the Copenhagen area. For light duty vehicles it is only profitable, if the prices of the filters fall to the price level that is expected in the future in the study. Further, the analysis shows that for light duty vehicles and taxies driving all over the country, the socioeconomic benefits achieved by installing particle filters are too small to cover the costs. The analysis shows that it is also profitable socio-economically to change from diesel to petrol for light duty vehicles and for taxies (except taxies driving nationally). The analysis is based on the producer prices including the general net tax level, while the specific taxes are not included. From the point of view of the companies it is not profitable to change to petrol

  1. A critical review of integrated urban water modellingUrban drainage and beyond

    DEFF Research Database (Denmark)

    Bach, Peter M.; Rauch, Wolfgang; Mikkelsen, Peter Steen

    2014-01-01

    considerations (e.g. data issues, model structure, computational and integration-related aspects), common methodology for model development (through a systems approach), calibration/optimisation and uncertainty are discussed, placing importance on pragmatism and parsimony. Integrated urban water models should......Modelling interactions in urban drainage, water supply and broader integrated urban water systems has been conceptually and logistically challenging as evidenced in a diverse body of literature, found to be confusing and intimidating to new researchers. This review consolidates thirty years...... of research (initially driven by interest in urban drainage modelling) and critically reflects upon integrated modelling in the scope of urban water systems. We propose a typology to classify integrated urban water system models at one of four ‘degrees of integration’ (followed by its exemplification). Key...

  2. Urban ecosystem modeling and global change: Potential for rational urban management and emissions mitigation

    International Nuclear Information System (INIS)

    Chen, Shaoqing; Chen, Bin; Fath, Brian D.

    2014-01-01

    Urbanization is a strong and extensive driver that causes environmental pollution and climate change from local to global scale. Modeling cities as ecosystems has been initiated by a wide range of scientists as a key to addressing challenging problems concomitant with urbanization. In this paper, ‘urban ecosystem modeling (UEM)’ is defined in an inter-disciplinary context to acquire a broad perception of urban ecological properties and their interactions with global change. Furthermore, state-of-the-art models of urban ecosystems are reviewed, categorized as top-down models (including materials/energy-oriented models and structure-oriented models), bottom-up models (including land use-oriented models and infrastructure-oriented models), or hybrid models thereof. Based on the review of UEM studies, a future framework for explicit UEM is proposed based the integration of UEM approaches of different scales, guiding more rational urban management and efficient emissions mitigation. - Highlights: • Urban ecosystems modeling (UEM) is defined in an interdisciplinary context. • State-of-the-art models for UEM are critically reviewed and compared. • An integrated framework for explicit UEM is proposed under global change. - State-of-the-art models of urban ecosystem modeling (UEM) are reviewed for rational urban management and emissions mitigation

  3. Modeling Urban Collaborative Growth Dynamics Using a Multiscale Simulation Model for the Wuhan Urban Agglomeration Area, China

    Directory of Open Access Journals (Sweden)

    Yan Yu

    2018-05-01

    Full Text Available Urban agglomeration has become the predominant form of urbanization in China. In this process, spatial interaction evidently played a significant role in promoting the collaborative development of these correlated cities. The traditional urban model’s focus on individual cities should be transformed to an urban system model. In this study, a multi-scale simulation model has been proposed to simulate the agglomeration development process of the Wuhan urban agglomeration area by embedding the multi-scale spatial interaction into the transition rule system of cellular automata (CA. A system dynamic model was used to predict the demand for new urban land at an aggregated urban agglomeration area scale. A data field approach was adopted to measuring the interaction of intercity at city scale. Neighborhood interaction was interpreted with a logistic regression method at the land parcel scale. Land use data from 1995, 2005, and 2015 were used to calibrate and evaluate the model. The simulation results show that there has been continuing urban growth in the Wuhan urban agglomeration area from 1995 to 2020. Although extension-sprawl was the predominant pattern of urban spatial expansion, the trend of extensive growth to intensive growth is clear during the entire period. The spatial interaction among these cities has been reinforced, which guided the collaborative development and formed the regional urban system network.

  4. PERFORMANCE AND DURABILITY OF THE PSA PEUGEOT CITROEN'S DPF SYSTEM ON A TAXI FLEET IN THE PARIS AREA

    Energy Technology Data Exchange (ETDEWEB)

    COROLLER, P; PLASSAT, G

    2003-08-24

    The use of Diesel engines has strongly increased during the last years and now represents 40% of the sales in Europe and up to 50% of the number of cars in circulation for some countries. This success is linked not only to the economical aspect of the use of such vehicles, but also to the recent technological improvements of these engines. The new technical solutions (high pressure direct injection, turbocharger) have indeed allowed the increase of these engine performances while decreasing their fuel consumption, pollutant emissions and noise level. From an environment point of view, Diesel engines are nevertheless penalized by their particulates and NOx emissions. The study and the treatment of the particulate, highly criticized for their potential impact on health, are the subject of numerous works of characterizations and developments. PSA Peugeot Citroen has recently (2000) launched its particulate filter technology on several types of vehicles (500,000 vehicles with DPF have been sold today). In order to evaluate the durability of this technology over a long period of time, a study program has been set-up by ADEME (French Environmental Agency), IFP Powertrain, PSA Peugeot Citroen and Taxis G7 (a Parisian taxis Company). The objective is to study the evolution of five taxis and their after-treatment system performances over 80,000km mileage--which corresponds to the recommended mileage before the first DPF maintenance--in hard urban driving conditions, as well over 120,000km, after the DPF maintenance and remanufacturing. More specifically, the following evaluations are being performed at regular intervals (around 20,000km): regulated gaseous pollutant emissions on NEDC cycle, particulate emissions and unregulated pollutant emissions. The results obtained until now have not shown any degradation of the particulate filter efficiency (more than 90%). This paper presents the methodology set-up, and the explanation of the first results obtained. Indeed, a more

  5. German taxi drivers' experiences and expressions of driving anger: Are the driving anger scale and the driving anger expression inventory valid measures?

    Science.gov (United States)

    Brandenburg, Stefan; Oehl, Michael; Seigies, Kristin

    2017-11-17

    The objective of this article was 2-fold: firstly, we wanted to examine whether the original Driving Anger Scale (DAS) and the original Driving Anger Expression Inventory (DAX) apply to German professional taxi drivers because these scales have previously been given to professional and particularly to nonprofessional drivers in different countries. Secondly, we wanted to examine possible differences in driving anger experience and expression between professional German taxi drivers and nonprofessional German drivers. We applied German versions of the DAS, the DAX, and the State-Trait Anger Expression Inventory (STAXI) to a sample of 138 professional German taxi drivers. We then compared their ratings to the ratings of a sample of 1,136 nonprofessional German drivers (Oehl and Brandenburg n.d. ). Regarding our first objective, confirmatory factor analysis shows that the model fit of the DAS is better for nonprofessional drivers than for professional drivers. The DAX applies neither to professional nor to nonprofessional German drivers properly. Consequently, we suggest modified shorter versions of both scales for professional drivers. The STAXI applies to both professional and nonprofessional drivers. With respect to our second objective, we show that professional drivers experience significantly less driving anger than nonprofessional drivers, but they express more driving anger. We conclude that the STAXI can be applied to professional German taxi drivers. In contrast, for the DAS and the DAX we found particular shorter versions for professional taxi drivers. Especially for the DAX, most statements were too strong for German drivers to agree to. They do not show behaviors related to driving anger expression as they are described in the DAX. These problems with the original American DAX items are in line with several other studies in different countries. Future investigations should examine whether (professional) drivers from further countries express their anger

  6. 41 CFR 301-10.421 - How much will my agency reimburse me for a tip to a taxi, shuttle service, or courtesy...

    Science.gov (United States)

    2010-07-01

    ... reimburse me for a tip to a taxi, shuttle service, or courtesy transportation driver? 301-10.421 Section 301..., Shuttle Services, Or Other Courtesy Transportation § 301-10.421 How much will my agency reimburse me for a tip to a taxi, shuttle service, or courtesy transportation driver? An amount which your agency...

  7. Development of a micro-hybrid system for a three-wheeled motor taxi

    NARCIS (Netherlands)

    Hofman, T.; Tas, van der S.G.; Ooms, W.; Van Meijl, E. W P; Laugeman, B. M.

    2009-01-01

    In large cities in Asia and Africa millions of auto-rickshaws offer their taxi-services. At the same time these three-wheelers cause severe air-pollution and produce large amounts of green house gasses (carbon dioxide). The goal of the research presented in this paper is to develop a compact, robust

  8. Relation between workplace accidents and the levels of carboxyhemoglobin in motorcycle taxi drivers.

    Science.gov (United States)

    da Silva, Luiz Almeida; Robazzi, Maria Lúcia do Carmo Cruz; Terra, Fábio de Souza

    2013-01-01

    To investigate the relation between workplace accidents and the levels of carboxyhemoglobin found in motorcycle taxi drivers. Correlational, quantitative study involving 111 workers and data obtained in July 2012 through a questionnaire to characterize the participants and blood collection to measure carboxyhemoglobin levels. 28.8% had suffered workplace accidents; 27.6% had fractured the lower limbs and significant symptoms of carbon monoxide exposure were verified in smokers. The carboxyhemoglobin levels were higher among smokers and victims of workplace accidents. Motorcycle taxi drivers had increased levels of carboxyhemoglobin, possibly due to the exposure to carbon monoxide; these levels are also increased among smokers and victims of workplace accidents. The study provides advances in the knowledge about occupational health and environmental science, and also shows that carboxyhemoglobin can be an indicator of exposure to environmental pollutants for those working outdoors, which can be related to workplace accidents.

  9. Attitudinal travel demand model for non-work trips of homogeneously constrained segments of a population

    Energy Technology Data Exchange (ETDEWEB)

    Recker, W.W.; Stevens, R.F.

    1977-06-01

    Market-segmentation techniques are used to capture effects of opportunity and availability constraints on urban residents' choice of mode for trips for major grocery shopping and for visiting friends and acquaintances. Attitudinal multinomial logit choice models are estimated for each market segment. Explanatory variables are individual's beliefs about attributes of four modal alternatives: bus, car, taxi and walking. Factor analysis is employed to identify latent dimensions of perception of the modal alternatives and to eliminate problems of multicollinearity in model estimation.

  10. Pattern of seat belt use and its associated factors among taxi drivers ...

    African Journals Online (AJOL)

    Objective: Road traffic injuries constitute a major public health concern that demands effective interventions. Use of car seat belts is recommended as an effective intervention to reduce serious and fatal road traffic injuries. The study intended to investigate the pattern of seat belt use and its correlates among taxi drivers in ...

  11. The Urban Food-Water Nexus: Modeling Water Footprints of Urban Agriculture using CityCrop

    Science.gov (United States)

    Tooke, T. R.; Lathuilliere, M. J.; Coops, N. C.; Johnson, M. S.

    2014-12-01

    Urban agriculture provides a potential contribution towards more sustainable food production and mitigating some of the human impacts that accompany volatility in regional and global food supply. When considering the capacity of urban landscapes to produce food products, the impact of urban water demand required for food production in cities is often neglected. Urban agricultural studies also tend to be undertaken at broad spatial scales, overlooking the heterogeneity of urban form that exerts an extreme influence on the urban energy balance. As a result, urban planning and management practitioners require, but often do not have, spatially explicit and detailed information to support informed urban agricultural policy, especially as it relates to potential conflicts with sustainability goals targeting water-use. In this research we introduce a new model, CityCrop, a hybrid evapotranspiration-plant growth model that incorporates detailed digital representations of the urban surface and biophysical impacts of the built environment and urban trees to account for the daily variations in net surface radiation. The model enables very fine-scale (sub-meter) estimates of water footprints of potential urban agricultural production. Results of the model are demonstrated for an area in the City of Vancouver, Canada and compared to aspatial model estimates, demonstrating the unique considerations and sensitivities for current and future water footprints of urban agriculture and the implications for urban water planning and policy.

  12. Modeling urban fire growth

    International Nuclear Information System (INIS)

    Waterman, T.E.; Takata, A.N.

    1983-01-01

    The IITRI Urban Fire Spread Model as well as others of similar vintage were constrained by computer size and running costs such that many approximations/generalizations were introduced to reduce program complexity and data storage requirements. Simplifications were introduced both in input data and in fire growth and spread calculations. Modern computational capabilities offer the means to introduce greater detail and to examine its practical significance on urban fire predictions. Selected portions of the model are described as presently configured, and potential modifications are discussed. A single tract model is hypothesized which permits the importance of various model details to be assessed, and, other model applications are identified

  13. Distributed models coupling soakaways, urban drainage and groundwater

    DEFF Research Database (Denmark)

    Roldin, Maria Kerstin

    in receiving waters, urban flooding etc. WSUD structures are generally small, decentralized systems intended to manage stormwater near the source. Many of these alternative techniques are based on infiltration which can affect both the urban sewer system and urban groundwater levels if widely implemented......Alternative methods for stormwater management in urban areas, also called Water Sensitive Urban Design (WSUD) methods, have become increasingly important for the mitigation of urban stormwater management problems such as high runoff volumes, combined sewage overflows, poor water quality......, and how these can be modeled in an integrated environment with distributed urban drainage and groundwater flow models. The thesis: 1. Identifies appropriate models of soakaways for use in an integrated and distributed urban water and groundwater modeling system 2. Develops a modeling concept that is able...

  14. A Comparative Study of Back Pain among Taxi and Truck Drivers in ...

    African Journals Online (AJOL)

    Data was analyzed using SSPSS version 20. Descriptive and analytical statistics to analyze and present data. The prevalence of back pain in Port Harcourt for taxi drivers was 70.4% and 71.4% for truck drivers. The prevalence among truck drivers was due to age ,sitting position and shock absorbers. However variables like ...

  15. Relation between workplace accidents and the levels of carboxyhemoglobin in motorcycle taxi drivers

    Directory of Open Access Journals (Sweden)

    Luiz Almeida da Silva

    2013-09-01

    Full Text Available OBJECTIVE: to investigate the relation between workplace accidents and the levels of carboxyhemoglobin found in motorcycle taxi drivers. METHOD: correlational, quantitative study involving 111 workers and data obtained in July 2012 through a questionnaire to characterize the participants and blood collection to measure carboxyhemoglobin levels. RESULT: 28.8% had suffered workplace accidents; 27.6% had fractured the lower limbs and significant symptoms of carbon monoxide exposure were verified in smokers. The carboxyhemoglobin levels were higher among smokers and victims of workplace accidents. CONCLUSION: motorcycle taxi drivers had increased levels of carboxyhemoglobin, possibly due to the exposure to carbon monoxide; these levels are also increased among smokers and victims of workplace accidents. The study provides advances in the knowledge about occupational health and environmental science, and also shows that carboxyhemoglobin can be an indicator of exposure to environmental pollutants for those working outdoors, which can be related to workplace accidents.

  16. The liver taxis of receptor mediated lactosaminated human growth hormone

    International Nuclear Information System (INIS)

    Chen Zelian; Shi Lin; Li Tongling; Pang Qijie; He Juying; Guan Changtian

    2002-01-01

    Radiography imaging is used to assess liver taxis mechanism of anti-dwarfism drug lactosaminated human growth hormone (L-rhGH). Both L-rhGH and rhGH labelled with 131 I are used to study their biodistribution in animals (including rabbits, cocks and rats). The results show that L-rhGH is of specific hepatic targeting property, and the maximum hepatic concentration rate is 76.8%, which is two times of rhGH. Its hepatic binding is receptor mediated

  17. Urban Land Allocation Model of Territorial Expansion by Urban Planners and Housing Developers

    Directory of Open Access Journals (Sweden)

    Carolina Cantergiani

    2017-12-01

    Full Text Available Agent-based models have recently been proposed as potential tools to support urban planning due to their capacity to simulate complex behaviors. The complexity of the urban development process arises from strong interactions between various components driven by different agents. AMEBA (agent-based model for the evolution of urban areas is a prototype of an exploratory, spatial, agent-based model that considers the main agents involved in the urban development process (urban planners, developers, and the population. The prototype consists of three submodels (one for each agent that have been developed independently and present the same structure. However, the first two are based on a land use allocation technique, and the last one, as well as their integration, on an agent-based model approach. This paper describes the conceptualization and performance of the submodels that represent urban planners and developers, who are the agents responsible for officially launching expansion and defining the spatial allocation of urban land. The prototype was tested in the Corredor del Henares (an urban–industrial area in the Region of Madrid, Spain, but is sufficiently flexible to be adapted to other study areas and generate different future urban growth contexts. The results demonstrate that this combination of agents can be used to explore various policy-relevant research questions, including urban system interactions in adverse political and socioeconomic scenarios.

  18. Modeling of facade leaching in urban catchments

    Science.gov (United States)

    Coutu, S.; Del Giudice, D.; Rossi, L.; Barry, D. A.

    2012-12-01

    Building facades are protected from microbial attack by incorporation of biocides within them. Flow over facades leaches these biocides and transports them to the urban environment. A parsimonious water quantity/quality model applicable for engineered urban watersheds was developed to compute biocide release from facades and their transport at the urban basin scale. The model couples two lumped submodels applicable at the basin scale, and a local model of biocide leaching at the facade scale. For the facade leaching, an existing model applicable at the individual wall scale was utilized. The two lumped models describe urban hydrodynamics and leachate transport. The integrated model allows prediction of biocide concentrations in urban rivers. It was applied to a 15 km2urban hydrosystem in western Switzerland, the Vuachère river basin, to study three facade biocides (terbutryn, carbendazim, diuron). The water quality simulated by the model matched well most of the pollutographs at the outlet of the Vuachère watershed. The model was then used to estimate possible ecotoxicological impacts of facade leachates. To this end, exceedance probabilities and cumulative pollutant loads from the catchment were estimated. Results showed that the considered biocides rarely exceeded the relevant predicted no-effect concentrations for the riverine system. Despite the heterogeneities and complexity of (engineered) urban catchments, the model application demonstrated that a computationally "light" model can be employed to simulate the hydrograph and pollutograph response within them. It thus allows catchment-scale assessment of the potential ecotoxicological impact of biocides on receiving waters.

  19. Taking actions to quit chewing betel nuts and starting a new life: taxi drivers' successful experiences of quitting betel nut chewing.

    Science.gov (United States)

    Yang, Tsui-Yun; Lin, Hung-Ru

    2017-04-01

    To understand taxi drivers' successful experiences of quitting betel nut chewing. Previous studies verified that betel nut chewing significantly increases the risk of oral cancer. In Taiwan, taxi drivers work for approximately 10-13 hours per day, and 31·7-80% of them choose to chew betel nuts for their invigorating qualities, which enable them to work more hours and receive more income. A qualitative research design was used. This study used the grounded theory method with purposive sampling to perform in-depth interviews with male taxi drivers who had successfully quit betel nut chewing for more than six months. The interviewed participants were 25 taxi drivers aged 45-67 who had chewed betel nuts for an average of 30·9 years. A constant comparative analysis of the 25 interviews revealed six categories, namely the first experience of chewing betel nuts, a part of work and life, perceiving the impact of betel nuts, trying to change, acting to quit betel nut chewing and starting a new life. During the cessation process, taxi drivers tended to be affected by their addiction to chewing betel nuts and the temptation of friends' invitations to chew betel nuts. However, their recognition of the physical effects of betel nut chewing and their sense of responsibility and commitment to family were the critical factors affecting their determination to quit betel nut chewing. Their willpower to not to chew betel nuts and the source of their motivation to exercise self-control also contributed to their success. Healthcare personnel should understand the experiences and perceptions of betel nut chewers, strengthen their understanding of the effects of betel nut chewing on physical health during the cessation period and support their self-efficacy and quitting behaviours with the assistance of significant others. © 2016 John Wiley & Sons Ltd.

  20. Kinetics and substrate selectivity of a Triticum aestivum xylanase inhibitor (TAXI) resistant D11F/R122D variant of Bacillus subtilis XynA xylanase

    DEFF Research Database (Denmark)

    Rasmussen, Louise Enggaard; Sørensen, Jens F.; Meyer, Anne S.

    2010-01-01

    This study examined the kinetics and substrate selectivity of a GH11 Bacillus subtilis XynA xylanase (BsX) sensitive to inhibition by TAXI and an engineered variant, which is much less inhibited by TAXI (BsX(mut)). The main purpose of the work was to elucidate any influence of the structural point...

  1. Operations of electric taxis to serve advance reservations by trip chaining: Sensitivity analysis on network size, customer demand and number of charging stations

    Directory of Open Access Journals (Sweden)

    Hao Wang

    2016-10-01

    Full Text Available This research investigated the performance of an Electric Taxi (ET fleet that catered solely for customers with advance reservations. In a previously related research, a customized Paired Pickup and Delivery Problem with Time Window and Charging Station (PPDPTWCS had been formulated to solve for the minimum number of taxis that would serve a fixed set of customer demand. The concept behind this fleet optimization was to chain multiple customer trips and trips to Charging Stations (CSs to form a route and assigned to a taxi driver. In this paper the sensitivity of the ET fleet’s operations with respect to network sizes, customer demand densities and number of CSs have been investigated. It also analyzed the market shares of the CSs and the occupancy of a CS over time. The results showed that, (1 the expansion of network size or the increase in customer demand density led to increase in fleet size, number of trips to the CSs and maximum occupancies at the CSs but these performance measures grew at different rates; (2 when the network size and number of CSs were fixed, an increase in customer demand density led to a better utilization of taxis in terms of more customers served per taxi and higher average revenue per taxi; (3 given the same network size and demand density, the ET fleet’s performance was relatively insensitive to the number of CSs; and (4 the usage of individual CS was affected by the number of CS and their locations; and (5 when all the ETs were fully charged at the beginning of the same shift hour, they visited the CSs in bunches when their batteries were about to run out. These findings contribute to a better understanding of the operations of the ET fleet and the CSs. They could be used for making better decisions in the planning of ET operations.

  2. PENINGKATAN HASIL BELAJAR PERPAJAKAN MELALUI MEDIA TAXI SNADERS PADA SISWA XI B SMK PL TARCISIUS 2

    Directory of Open Access Journals (Sweden)

    Cornelius Hery Setyawan

    2016-01-01

    Full Text Available Vocational School (SMK is an educational institution to transfer knowledge about the tax. Unluckily, teaching learning process in delivering this material was monotonous, so it needed a medium called TAXI SNADERS. The objective of the study was to increase interest and learning outcomes taxation on Value Added Tax (VAT and Sales of Luxury through a medium called TAXI SNADERS. The result of the study showed that there was improvement toward students’ interest for 14.5%. On the 1st cycle, students’ interest was only 67.25%, then it increased up to 81.75% on the 2nd cycle. Moreover, students’ learning outcomes also increased for 20% in post test. It was 67% on the 1st cycle and rose to 87% on the 2nd cycle. 

  3. Carbon emissions tax policy of urban road traffic and its application in Panjin, China

    Science.gov (United States)

    Yang, Longhai; Fang, Lin

    2018-01-01

    How to effectively solve traffic congestion and transportation pollution in urban development is a main research emphasis for transportation management agencies. A carbon emissions tax can affect travelers’ generalized costs and will lead to changes in passenger demand, mode choice and traffic flow equilibrium in road networks, which are of significance in green travel and low-carbon transportation management. This paper first established a mesoscopic model to calculate the carbon emissions tax and determined the value of this charge in China, which was based on road traffic flow, vehicle speed, and carbon emissions. Referring to existing research results to calibrate the value of time, this paper modified the traveler’s generalized cost function, including the carbon emissions tax, fuel surcharge and travel time cost, which can be used in the travel impedance model with the consideration of the carbon emissions tax. Then, a method for analyzing urban road network traffic flow distribution was put forward, and a joint traffic distribution model was established, which considered the relationship between private cars and taxis. Finally, this paper took the city of Panjin as an example to analyze the road traffic carbon emissions tax’s impact. The results illustrated that the carbon emissions tax has a positive effect on road network flow equilibrium and carbon emission reduction. This paper will have good reference value and practical significance for the calculation and implementation of urban traffic carbon emissions taxes in China. PMID:29738580

  4. Carbon emissions tax policy of urban road traffic and its application in Panjin, China.

    Science.gov (United States)

    Yang, Longhai; Hu, Xiaowei; Fang, Lin

    2018-01-01

    How to effectively solve traffic congestion and transportation pollution in urban development is a main research emphasis for transportation management agencies. A carbon emissions tax can affect travelers' generalized costs and will lead to changes in passenger demand, mode choice and traffic flow equilibrium in road networks, which are of significance in green travel and low-carbon transportation management. This paper first established a mesoscopic model to calculate the carbon emissions tax and determined the value of this charge in China, which was based on road traffic flow, vehicle speed, and carbon emissions. Referring to existing research results to calibrate the value of time, this paper modified the traveler's generalized cost function, including the carbon emissions tax, fuel surcharge and travel time cost, which can be used in the travel impedance model with the consideration of the carbon emissions tax. Then, a method for analyzing urban road network traffic flow distribution was put forward, and a joint traffic distribution model was established, which considered the relationship between private cars and taxis. Finally, this paper took the city of Panjin as an example to analyze the road traffic carbon emissions tax's impact. The results illustrated that the carbon emissions tax has a positive effect on road network flow equilibrium and carbon emission reduction. This paper will have good reference value and practical significance for the calculation and implementation of urban traffic carbon emissions taxes in China.

  5. Spatial stochastic regression modelling of urban land use

    International Nuclear Information System (INIS)

    Arshad, S H M; Jaafar, J; Abiden, M Z Z; Latif, Z A; Rasam, A R A

    2014-01-01

    Urbanization is very closely linked to industrialization, commercialization or overall economic growth and development. This results in innumerable benefits of the quantity and quality of the urban environment and lifestyle but on the other hand contributes to unbounded development, urban sprawl, overcrowding and decreasing standard of living. Regulation and observation of urban development activities is crucial. The understanding of urban systems that promotes urban growth are also essential for the purpose of policy making, formulating development strategies as well as development plan preparation. This study aims to compare two different stochastic regression modeling techniques for spatial structure models of urban growth in the same specific study area. Both techniques will utilize the same datasets and their results will be analyzed. The work starts by producing an urban growth model by using stochastic regression modeling techniques namely the Ordinary Least Square (OLS) and Geographically Weighted Regression (GWR). The two techniques are compared to and it is found that, GWR seems to be a more significant stochastic regression model compared to OLS, it gives a smaller AICc (Akaike's Information Corrected Criterion) value and its output is more spatially explainable

  6. Evaluation of the WRF-Urban Modeling System Coupled to Noah and Noah-MP Land Surface Models Over a Semiarid Urban Environment

    Science.gov (United States)

    Salamanca, Francisco; Zhang, Yizhou; Barlage, Michael; Chen, Fei; Mahalov, Alex; Miao, Shiguang

    2018-03-01

    We have augmented the existing capabilities of the integrated Weather Research and Forecasting (WRF)-urban modeling system by coupling three urban canopy models (UCMs) available in the WRF model with the new community Noah with multiparameterization options (Noah-MP) land surface model (LSM). The WRF-urban modeling system's performance has been evaluated by conducting six numerical experiments at high spatial resolution (1 km horizontal grid spacing) during a 15 day clear-sky summertime period for a semiarid urban environment. To assess the relative importance of representing urban surfaces, three different urban parameterizations are used with the Noah and Noah-MP LSMs, respectively, over the two major cities of Arizona: Phoenix and Tucson metropolitan areas. Our results demonstrate that Noah-MP reproduces somewhat better than Noah the daily evolution of surface skin temperature and near-surface air temperature (especially nighttime temperature) and wind speed. Concerning the urban areas, bulk urban parameterization overestimates nighttime 2 m air temperature compared to the single-layer and multilayer UCMs that reproduce more accurately the daily evolution of near-surface air temperature. Regarding near-surface wind speed, only the multilayer UCM was able to reproduce realistically the daily evolution of wind speed, although maximum winds were slightly overestimated, while both the single-layer and bulk urban parameterizations overestimated wind speed considerably. Based on these results, this paper demonstrates that the new community Noah-MP LSM coupled to an UCM is a promising physics-based predictive modeling tool for urban applications.

  7. Urban Sprawl Analysis and Modeling in Asmara, Eritrea

    Directory of Open Access Journals (Sweden)

    Mussie G. Tewolde

    2011-09-01

    Full Text Available The extension of urban perimeter markedly cuts available productive land. Hence, studies in urban sprawl analysis and modeling play an important role to ensure sustainable urban development. The urbanization pattern of the Greater Asmara Area (GAA, the capital of Eritrea, was studied. Satellite images and geospatial tools were employed to analyze the spatiotemporal urban landuse changes. Object-Based Image Analysis (OBIA, Landuse Cover Change (LUCC analysis and urban sprawl analysis using Shannon Entropy were carried out. The Land Change Modeler (LCM was used to develop a model of urban growth. The Multi-layer Perceptron Neural Network was employed to model the transition potential maps with an accuracy of 85.9% and these were used as an input for the ‘actual’ urban modeling with Markov chains. Model validation was assessed and a scenario of urban land use change of the GAA up to year 2020 was presented. The result of the study indicated that the built-up area has tripled in size (increased by 4,441 ha between 1989 and 2009. Specially, after year 2000 urban sprawl in GAA caused large scale encroachment on high potential agricultural lands and plantation cover. The scenario for year 2020 shows an increase of the built-up areas by 1,484 ha (25% which may cause further loss. The study indicated that the land allocation system in the GAA overrode the landuse plan, which caused the loss of agricultural land and plantation cover. The recommended policy options might support decision makers to resolve further loss of agricultural land and plantation cover and to achieve sustainable urban development planning in the GAA.

  8. Smart Mobility Stakeholders - Curating Urban Data & Models

    Energy Technology Data Exchange (ETDEWEB)

    Sperling, Joshua [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-09-01

    This presentation provides an overview of the curation of urban data and models through engaging SMART mobility stakeholders. SMART Mobility Urban Science Efforts are helping to expose key data sets, models, and roles for the U.S. Department of Energy in engaging across stakeholders to ensure useful insights. This will help to support other Urban Science and broader SMART initiatives.

  9. Modelling and observing urban climate in the Netherlands

    International Nuclear Information System (INIS)

    Van Hove, B.; Steeneveld, G.J.; Heusinkveld, B.; Holtslag, B.; Jacobs, C.; Ter Maat, H.; Elbers, J.; Moors, E.

    2011-06-01

    The main aims of the present study are: (1) to evaluate the performance of two well-known mesoscale NWP (numerical weather prediction) models coupled to a UCM (Urban Canopy Models), and (2) to develop a proper measurement strategy for obtaining meteorological data that can be used in model evaluation studies. We choose the mesoscale models WRF (Weather Research and Forecasting Model) and RAMS (Regional Atmospheric Modeling System), respectively, because the partners in the present project have a large expertise with respect to these models. In addition WRF and RAMS have been successfully used in the meteorology and climate research communities for various purposes, including weather prediction and land-atmosphere interaction research. Recently, state-of-the-art UCM's were embedded within the land surface scheme of the respective models, in order to better represent the exchange of heat, momentum, and water vapour in the urban environment. Key questions addressed here are: What is the general model performance with respect to the urban environment?; How can useful and observational data be obtained that allow sensible validation and further parameterization of the models?; and Can the models be easily modified to simulate the urban climate under Dutch climatic conditions, urban configuration and morphology? Chapter 2 reviews the available Urban Canopy Models; we discuss their theoretical basis, the different representations of the urban environment, the required input and the output. Much of the information was obtained from the Urban Surface Energy Balance: Land Surface Scheme Comparison project (PILPS URBAN, PILPS stands for Project for Inter-comparison of Land-Surface Parameterization Schemes). This project started in March 2008 and was coordinated by the Department of Geography, King's College London. In order to test the performance of our models we participated in this project. Chapter 3 discusses the main results of the first phase of PILPS URBAN. A first

  10. Taxi drivers' views on risky driving behavior in Tehran: a qualitative study using a social marketing approach.

    Science.gov (United States)

    Shams, Mohsen; Shojaeizadeh, Davoud; Majdzadeh, Reza; Rashidian, Arash; Montazeri, Ali

    2011-05-01

    The use of the social marketing approach for public health issues is increasing. This approach uses marketing concepts borrowed from the principles of commercial marketing to promote beneficial health behaviors. In this qualitative study, four focus groups involving 42 participants were used in consumer research to explore taxi drivers' views on the driving situation and the determinants of risky driving behaviors in Tehran, as well as to gather their ideas for developing a social marketing program to reduce risky driving behaviors among taxi drivers in Tehran, Iran. Participants were asked to respond to questions that would guide the development of a marketing mix, or four Ps (product, price, place and promotion). The discussions determined that the program product should involve avoiding risky driving behaviors through increased attention to driving. They pointed out that developing and communicating with a well-designed persuasive message meant to draw their attention to driving could affect their driving behaviors. In addition, participants identified price, place and promotion strategies. They offered suggestions for marketing nonrisky driving to the target audience. The focus group discussions generated important insights into the values and the motivations that affect consumers' decisions to adopt the product. The focus group guided the development of a social marketing program to reduce risky driving behaviors in taxi drivers in Tehran, Iran. Copyright © 2010 Elsevier Ltd. All rights reserved.

  11. Modelling the impact of Water Sensitive Urban Design technologies on the urban water cycle

    DEFF Research Database (Denmark)

    Locatelli, Luca

    Alternative stormwater management approaches for urban developments, also called Water Sensitive Urban Design (WSUD), are increasingly being adopted with the aims of providing flood control, flow management, water quality improvements and opportunities to harvest stormwater for non-potable uses....... To model the interaction of infiltration based WSUDs with groundwater. 4. To assess a new combination of different WSUD techniques for improved stormwater management. 5. To model the impact of a widespread implementation of multiple soakaway systems at the catchment scale. 6. Test the models by simulating...... the hydrological performance of single devices relevant for urban drainage applications. Moreover, the coupling of soakaway and detention storages is also modeled to analyze the benefits of combining different local stormwater management systems. These models are then integrated into urban drainage network models...

  12. Aspergillus prevalence in air conditioning filters from vehicles: taxis for patient transportation, forklifts, and personal vehicles.

    Science.gov (United States)

    Viegas, Carla; Moreira, Ricardo; Faria, Tiago; Caetano, Liliana Aranha; Carolino, Elisabete; Gomes, Anita Quintal; Viegas, Susana

    2018-05-04

    The frequency and importance of Aspergillus infections is increasing worldwide. This study aimed to assess the occupational exposure of forklifts and taxi drivers to Aspergillus spp. Nineteen filters from air conditioning system of taxis, 17 from forklifts and 37 from personal vehicles were assessed. Filters extract were streaked onto MEA, DG18 and in azole-supplemented media. Real-time quantitative PCR amplification of selected Aspergillus species-complex was also performed. Forklifts filter samples presented higher median values. Aspergillus section Nigri was the most observed in forklifts filters in MEA (28.2%) and in azole-supplemented media. DNA from Aspergillus sections Fumigati and Versicolores was successfully amplified by qPCR. This study enlightens the added value of using filters from the air conditioning system to assess Aspergillus spp. occupational exposure. Aspergillus azole resistance screening should be included in future occupational exposure assessments.

  13. Urban Intersection Recognition and Construction Based on Big Trace Data

    Directory of Open Access Journals (Sweden)

    TANG Luliang

    2017-06-01

    Full Text Available Intersection is an important part of the generation and renewal of urban traffic network. In this paper, a new method was proposed to detect urban intersections automatically from the spatiotemporal big trace data. Firstly, the turning point pairs were based on tracking the trace data collected by vehicles. Secondly, different types of turning point pairs were clustered by using spatial growing clustering method based on angle and distance differences, and the clustering methods of local connectivity was used to recognize the intersection. Finally, the intersection structure of multi-level road network was constructed with the range of the intersection and turning point pairs. Taking the taxi trajectory data in Wuhan city as an example, the experimental results showed that the method proposed in this paper can automatically detect and recognize the road intersection and its structure.

  14. The Urban Forest Effects (UFORE) model: quantifying urban forest structure and functions

    Science.gov (United States)

    David J. Nowak; Daniel E. Crane

    2000-01-01

    The Urban Forest Effects (UFORE) computer model was developed to help managers and researchers quantify urban forest structure and functions. The model quantifies species composition and diversity, diameter distribution, tree density and health, leaf area, leaf biomass, and other structural characteristics; hourly volatile organic compound emissions (emissions that...

  15. The Effects of Projected Future Demand Including Very Light Jet Air-Taxi Operations on U.S. National Airspace System Delays as a Function of Next Generation Air Transportation System Airspace Capacity

    Science.gov (United States)

    Smith, Jerry; Viken, Jeff; Dollyhigh, Samuel; Trani, Antonio; Baik, Hojong; Hinze, Nicholas; Ashiabor, Senanu

    2007-01-01

    This paper presents the results from a study which investigates the potential effects of the growth in air traffic demand including projected Very Light Jet (VLJ) air-taxi operations adding to delays experienced by commercial passenger air transportation in the year 2025. The geographic region studied is the contiguous United States (U.S.) of America, although international air traffic to and from the U.S. is included. The main focus of this paper is to determine how much air traffic growth, including VLJ air-taxi operations will add to enroute airspace congestion and determine what additional airspace capacity will be needed to accommodate the expected demand. Terminal airspace is not modeled and increased airport capacity is assumed.

  16. Prevalence and factors associated with road traffic crash among taxi drivers in Mekelle town, northern Ethiopia, 2014: a cross sectional study.

    Directory of Open Access Journals (Sweden)

    Nigus Gebremedhin Asefa

    Full Text Available The 2013 World Health Organization Status Report on Road Safety estimated that approximately 1.24 million deaths occur annually due to road traffic crashes with most of the burden falling on low- and middle-income countries. The objective of this research is to study the prevalence of road traffic crashes in Mekelle, Tigray, Northern Ethiopia and to identify risk factors with the ultimate goal of informing prevention activities and policies.This study used a cross-sectional design to measure the prevalence and factors associated with road traffic crashes among 4-wheeled minibus (n = 130 and 3-wheeled Bajaj (n = 582 taxi drivers in Mekelle, Ethiopia. Bivariate and multivariate logistic regression were used to evaluate the association between risk factors and drivers' involvement in a road traffic crash within the 3 years prior to the survey.Among the 712 taxi drivers, 26.4% (n = 188 of them reported involvement in a road traffic crash within the past 3 years. Drivers who listened to mass media had decreased likelihood of road traffic crash involvement (AOR = 0.51, 0.33-0.78, while speedy driving (AOR = 4.57, 3.05-7.44, receipt of a prior traffic punishment (AOR = 4.57, 2.67-7.85, and driving a mechanically faulty taxi (AOR = 4.91, 2.81-8.61 were strongly associated with road traffic crash involvement. Receiving mobile phone calls while driving (AOR = 1.91, 1.24-2.92 and history of alcohol use (AOR = 1.51, 1.00-2.28 were also associated with higher odds of road traffic crash involvement.The results of this study show that taxi drivers in Mekelle habitually place themselves at increased risk of road traffic crashes by violating traffic laws, especially related to speedy driving, mobile phone use, and taxi maintenance. This research can be used to support re-evaluation of the type, severity, and enforcement of traffic violation penalties.

  17. Developing Policy for Urban Autonomous Vehicles: Impact on Congestion

    Directory of Open Access Journals (Sweden)

    David Metz

    2018-04-01

    Full Text Available An important problem for surface transport is road traffic congestion, which is ubiquitous and difficult to mitigate. Accordingly, a question for policymakers is the possible impact on congestion of autonomous vehicles. It seems likely that the main impact of vehicle automation will not be seen until driverless vehicles are sufficiently safe for use amid general traffic on urban streets. Shared use driverless vehicles could reduce the cost of taxis and a wider range of public transport vehicles could be economic. Individually owned autonomous vehicles would have the ability to travel unoccupied and may need to be regulated where this might add to congestion. It is possible that autonomous vehicles could provide mobility services at lower cost and wider scope, such that private car use in urban areas could decline and congestion reduce. City authorities should be alert to these possibilities in developing transport policy.

  18. Vehicle rental with driver (VTC and its legal implications. Uber, Cabify and the colaborative economy

    Directory of Open Access Journals (Sweden)

    Nicolás Alejandro Guillén Navarro

    2018-04-01

    Full Text Available In recent years, the taxi industry has faced the incursion of collaborative economy in urban passenger transport in passenger cars. P2P platforms like Uber or Cabify try to compete in this sector monopolized by the taxi. In this sense, the transit of the use of the collaborative transport model to the lease of vehicle with driver (VTC has legally helped these platforms. However, the debate as to whether the Uber or Cabify benefits should be associated with the principle of freedom to provide services or whether they are included in the transport sector are still present. This study aims to analyze all these issues, focusing both on the legal regime of the taxi, as on the VTC, and how the struggle between the taxi sector and the advancement of these p2p service is being solved.

  19. Field dispersal ability and taxis to sex pheromone of irradiated F-1 male Asian corn borer

    International Nuclear Information System (INIS)

    Wang Huasong; Liu Qiongru; Lu Daguang; Wang Endong; Kang Wen; Li Yongjun; He Qiulan; Hu Jianguo

    1998-01-01

    The dispersal ability of F-1 male Asian corn borer, Ostrinia furnacalis (Guenee), irradiated with 100, 150 and 200 Gy Separately in parental generation were tested by marking (with Calco oil red or Sudan blue internally)-releasing-recapturing (with synthesized sex pheromone) method in the field where the farthest distance from release point to pheromone trap was 550 m. The results showed that, as compared with the normal male moths, despite of the fact that a part of the irradiated F-1 males had lost dispersal ability or taxis to sex pheromone, there was no significant difference between the captured rates of irradiated F-1 males and normal males in the trap 550 m from release point, indicated that the dispersal ability or taxis to sex pheromone of irradiated F-1 males arrived at 550 m from release point are still well matched with the normal ones

  20. Understanding complex urban systems multidisciplinary approaches to modeling

    CERN Document Server

    Gurr, Jens; Schmidt, J

    2014-01-01

    Understanding Complex Urban Systems takes as its point of departure the insight that the challenges of global urbanization and the complexity of urban systems cannot be understood – let alone ‘managed’ – by sectoral and disciplinary approaches alone. But while there has recently been significant progress in broadening and refining the methodologies for the quantitative modeling of complex urban systems, in deepening the theoretical understanding of cities as complex systems, or in illuminating the implications for urban planning, there is still a lack of well-founded conceptual thinking on the methodological foundations and the strategies of modeling urban complexity across the disciplines. Bringing together experts from the fields of urban and spatial planning, ecology, urban geography, real estate analysis, organizational cybernetics, stochastic optimization, and literary studies, as well as specialists in various systems approaches and in transdisciplinary methodologies of urban analysis, the volum...

  1. The Correlation between Duration of Employment, Body Posture and Smoking Habit on Low Back Pain Incidence An Analytic Observational Study Among Taxi Driver in Semarang Municipality

    Directory of Open Access Journals (Sweden)

    Syifa Dian Firmanita

    2015-06-01

    Full Text Available Introduction: Low back pain ((LBP ranks as number two of neurological disease’s highest prevalence after cephalgia and migraine in Indonesia. Objective: This study aim to determine the relationship between duration of employment, body posture and smoking habit on the incidence of low back pain on taxi driver. Method: This research is an observational analytic cross sectional design. Seventyfour taxi drivers in Semarang municipality was screened with Beck’s Depression Inventory Scale to meet the inclusion and exclusion criteria. Respondents were then given Risk Factor of LBP questionnaire. Data were analyzed with a bivariate correlation test contingency coefficient to see the relationship between duration of employment, body posture, smoking habit and low back pain.Result: the taxi driver with duration of employment >10 years were moderate smokers and having astenis body posture. The analysis of correlation coefficients contingency test showed a significance relationship between duration of employment (p = 0,000, body posture (p = 0,000, and moderate smokers (p=0.010 with the incidence of LBP. Conclusion: the taxi driver with duration of employment >10 years with astenis body posture, and moderate smokers were posstively correlated with LBP.

  2. Urban flood simulation based on the SWMM model

    Directory of Open Access Journals (Sweden)

    L. Jiang

    2015-05-01

    Full Text Available China is the nation with the fastest urbanization in the past decades which has caused serious urban flooding. Flood forecasting is regarded as one of the important flood mitigation methods, and is widely used in catchment flood mitigation, but is not widely used in urban flooding mitigation. This paper, employing the SWMM model, one of the widely used urban flood planning and management models, simulates the urban flooding of Dongguan City in the rapidly urbanized southern China. SWMM is first set up based on the DEM, digital map and underground pipeline network, then parameters are derived based on the properties of the subcatchment and the storm sewer conduits; the parameter sensitivity analysis shows the parameter robustness. The simulated results show that with the 1-year return period precipitation, the studied area will have no flooding, but for the 2-, 5-, 10- and 20-year return period precipitation, the studied area will be inundated. The results show the SWMM model is promising for urban flood forecasting, but as it has no surface runoff routing, the urban flooding could not be forecast precisely.

  3. Urban eco-efficiency and system dynamics modelling

    Energy Technology Data Exchange (ETDEWEB)

    Hradil, P., Email: petr.hradil@vtt.fi

    2012-06-15

    Assessment of urban development is generally based on static models of economic, social or environmental impacts. More advanced dynamic models have been used mostly for prediction of population and employment changes as well as for other macro-economic issues. This feasibility study was arranged to test the potential of system dynamic modelling in assessing eco-efficiency changes during urban development. (orig.)

  4. A New Era for Urban Modelling

    OpenAIRE

    Pumain , Denise

    1994-01-01

    International audience; In the last two decades, several interesting innovations have appeared in the field of urban research. New paradigms such as the dynamics of open systems, self-organization, synergetics, chaos, evolution, were recognized as conveying fruitful analogies for urban theory. New types of modeling were investigated, as sets of non-linear differential equations for spatial systems, cellular automata, multi-agents models, fractal growth, neural networks, evolutionary models… H...

  5. Modeling Global Urbanization Supported by Nighttime Light Remote Sensing

    Science.gov (United States)

    Zhou, Y.

    2015-12-01

    Urbanization, a major driver of global change, profoundly impacts our physical and social world, for example, altering carbon cycling and climate. Understanding these consequences for better scientific insights and effective decision-making unarguably requires accurate information on urban extent and its spatial distributions. In this study, we developed a cluster-based method to estimate the optimal thresholds and map urban extents from the nighttime light remote sensing data, extended this method to the global domain by developing a computational method (parameterization) to estimate the key parameters in the cluster-based method, and built a consistent 20-year global urban map series to evaluate the time-reactive nature of global urbanization (e.g. 2000 in Fig. 1). Supported by urban maps derived from nightlights remote sensing data and socio-economic drivers, we developed an integrated modeling framework to project future urban expansion by integrating a top-down macro-scale statistical model with a bottom-up urban growth model. With the models calibrated and validated using historical data, we explored urban growth at the grid level (1-km) over the next two decades under a number of socio-economic scenarios. The derived spatiotemporal information of historical and potential future urbanization will be of great value with practical implications for developing adaptation and risk management measures for urban infrastructure, transportation, energy, and water systems when considered together with other factors such as climate variability and change, and high impact weather events.

  6. Urban Hydrology and Water Quality Modeling - Resolution Modeling Comparison for Water Quantity and Quality

    Science.gov (United States)

    Fry, T. J.; Maxwell, R. M.

    2014-12-01

    Urbanization presents challenging water resource problems for communities worldwide. The hydromodifications associated with urbanization results in increased runoff rates and volumes and increased peak flows. These hydrologic changes can lead to increased erosion and stream destabilization, decreased evapotranspiration, decreased ground water recharge, increases in pollutant loading, and localized anthropogenic climate change or Urban Heat Islands. Stormwater represents a complex and dynamic component of the urban water cycle that requires careful mitigation. With the implementation of Phase II rules under the CWA, stormwater management is shifting from a drainage-efficiency focus to a natural systems focus. The natural system focus, referred to as Low Impact Development (LID), or Green Infrastructure, uses best management practices (BMPs) to reduce the impacts caused by urbanization hydromodification. Large-scale patterns of stormwater runoff from urban environments are complex and it is unclear what the large-scale impacts of green infrastructure are on the water cycle. High resolution physically based hydrologic models can be used to more accurately simulate the urban hydrologic cycle. These types of models tend to be more dynamic and allow for greater flexibility in evaluating and accounting for various hydrologic processes in the urban environment that may be lost with lower resolution conceptual models. We propose to evaluate the effectiveness of high resolution models to accurately represent and determine the urban hydrologic cycle with the overall goal of being able to accurately assess the impacts of LID BMPs in urban environments. We propose to complete a rigorous model intercomparison between ParFlow and FLO-2D. Both of these models can be scaled to higher resolutions, allow for rainfall to be spatially and temporally input, and solve the shallow water equations. Each model is different in the way it accounts for infiltration, initial abstraction losses

  7. SOME EMPIRICAL RELATIONS BETWEEN TRAVEL SPEED, TRAFFIC VOLUME AND TRAFFIC COMPOSITION IN URBAN ARTERIALS

    Directory of Open Access Journals (Sweden)

    Eleni I. VLAHOGIANNI, Ph.D.

    2007-01-01

    Full Text Available The effects of traffic mix (the percentage of cars, trucks, buses and so on are of particular interest in the speed-volume relationship in urban signalized arterials under various geometric and control characteristics. The paper presents some empirical observations on the relation between travel speed, traffic volume and traffic composition in urban signalized arterials. A methodology based on emerging self-organizing structures of neural networks to identify regions in the speed-volume relationship with respect to traffic composition and Bayesian networks to evaluate the effect of different types of motorized vehicles on prevailing traffic conditions is proposed. Results based on data from a large urban network indicate that the variability in traffic conditions can be described by eight regions in speed-volume relationship with respect to traffic composition. Further evaluation of the effect of motorized vehicles in each region separately indicates that the effect of traffic composition decreases with the onset of congestion. Moreover, taxis and motorcycles are the primary affecting parameter of the form of the speed-volume relationship in urban arterials.

  8. Detecting Anomaly in Traffic Flow from Road Similarity Analysis

    KAUST Repository

    Liu, Xinran; Liu, Xingwu; Wang, Yuanhong; Pu, Juhua; Zhang, Xiangliang

    2016-01-01

    Taxies equipped with GPS devices are considered as 24-hour moving sensors widely distributed in urban road networks. Plenty of accurate and realtime trajectories of taxi are recorded by GPS devices and are commonly studied for understanding traffic

  9. Multiple-Factor Based Sparse Urban Travel Time Prediction

    Directory of Open Access Journals (Sweden)

    Xinyan Zhu

    2018-02-01

    Full Text Available The prediction of travel time is challenging given the sparseness of real-time traffic data and the uncertainty of travel, because it is influenced by multiple factors on the congested urban road networks. In our paper, we propose a three-layer neural network from big probe vehicles data incorporating multi-factors to estimate travel time. The procedure includes the following three steps. First, we aggregate data according to the travel time of a single taxi traveling a target link on working days as traffic flows display similar traffic patterns over a weekly cycle. We then extract feature relationships between target and adjacent links at 30 min interval. About 224,830,178 records are extracted from probe vehicles. Second, we design a three-layer artificial neural network model. The number of neurons in input layer is eight, and the number of neurons in output layer is one. Finally, the trained neural network model is used for link travel time prediction. Different factors are included to examine their influence on the link travel time. Our model is verified using historical data from probe vehicles collected from May to July 2014 in Wuhan, China. The results show that we could obtain the link travel time prediction results using the designed artificial neural network model and detect the influence of different factors on link travel time.

  10. Combining multimedia models with integrated urban water system models for micropollutants

    DEFF Research Database (Denmark)

    De Keyser, W.; Gevaert, V.; Verdonck, F.

    2009-01-01

    Integrated urban water system (IUWS) modelling aims at assessing the quality of the surface water receiving the urban emissions through sewage treatment plants, combined sewer overflows (CSOs) and stormwater drainage systems. However, some micropollutants have the tendency to occur in more than one...... environmental medium. In this work, a multimedia fate and transport model (MFTM) is “wrapped around” a dynamic IUWS model for organic micropollutants to enable integrated environmental assessment. The combined model was tested on a hypothetical catchment using two scenarios: a reference scenario...... and a stormwater infiltration pond scenario, as an example of a sustainable urban drainage system (SUDS). A case for Bis(2-ethylhexyl) phthalate (DEHP) was simulated and resulted in a reduced surface water concentration for the latter scenario. However, the model also showed that this was at the expense...

  11. Integrated city as a model for a new wave urban tourism

    Science.gov (United States)

    Ariani, V.

    2018-03-01

    Cities are a major player for an urban tourism destination. Massive tourism movement for urban tourism gains competitiveness to the city with similar characteristic. The new framework model for new wave urban tourism is crucial to give more experience to the tourist and valuing for the city itself. The integrated city is the answer for creating a new model for an urban tourism destination. The purpose of this preliminary research is to define integrated city framework for urban tourism development. It provides a rationale for tourism planner pursuing an innovative approach, competitive advantages, and general urban tourism destination model. The methodology applies to this research includes desk survey, literature review and focus group discussion. A conceptual framework is proposed, discussed and exemplified. The framework model adopts a place-based approach to tourism destination and suggests an integrated city model for urban tourism development. This model is a tool for strategy making in re-invention integrated city as an urban tourism destination.

  12. Swarm Intelligence for Urban Dynamics Modelling

    International Nuclear Information System (INIS)

    Ghnemat, Rawan; Bertelle, Cyrille; Duchamp, Gerard H. E.

    2009-01-01

    In this paper, we propose swarm intelligence algorithms to deal with dynamical and spatial organization emergence. The goal is to model and simulate the developement of spatial centers using multi-criteria. We combine a decentralized approach based on emergent clustering mixed with spatial constraints or attractions. We propose an extension of the ant nest building algorithm with multi-center and adaptive process. Typically, this model is suitable to analyse and simulate urban dynamics like gentrification or the dynamics of the cultural equipment in urban area.

  13. Swarm Intelligence for Urban Dynamics Modelling

    Science.gov (United States)

    Ghnemat, Rawan; Bertelle, Cyrille; Duchamp, Gérard H. E.

    2009-04-01

    In this paper, we propose swarm intelligence algorithms to deal with dynamical and spatial organization emergence. The goal is to model and simulate the developement of spatial centers using multi-criteria. We combine a decentralized approach based on emergent clustering mixed with spatial constraints or attractions. We propose an extension of the ant nest building algorithm with multi-center and adaptive process. Typically, this model is suitable to analyse and simulate urban dynamics like gentrification or the dynamics of the cultural equipment in urban area.

  14. The implementation of biofiltration systems, rainwater tanks and urban irrigation in a single-layer urban canopy model

    Science.gov (United States)

    Demuzere, Matthias; Coutts, Andrew; Goehler, Maren; Broadbent, Ashley; Wouters, Hendrik; van Lipzig, Nicole; Gebert, Luke

    2015-04-01

    Urban vegetation is generally considered as a key tool to modify the urban energy balance through enhanced evapotranspiration (ET). Given that vegetation is most effective when it is healthy, stormwater harvesting and retention strategies (such as water sensitive urban design) could be used to support vegetation and promote ET. This study presents the implementation of a vegetated lined bio-filtration system (BFS) combined with a rainwater tank (RWT) and urban irrigation system in the single-layer urban canopy model Community Land Model-Urban. Runoff from roof and impervious road surface fractions is harvested and used to support an adequate soil moisture level for vegetation in the BFS. In a first stage, modelled soil moisture dynamics are evaluated and found reliable compared to observed soil moisture levels from biofiltration pits in Smith Street, Melbourne (Australia). Secondly, the impact of BFS, RWT and urban irrigation on ET is illustrated for a two-month period in 2012 using varying characteristics for all components. Results indicate that (i) a large amount of stormwater is potentially available for indoor and outdoor water demands, including irrigation of urban vegetation, (ii) ET from the BFS is an order of magnitude larger compared to the contributions from the impervious surfaces, even though the former only covers 10% of the surface fraction and (iii) attention should be paid to the cover fraction and soil texture of the BFS, size of the RWT and the surface fractions contributing to the collection of water in the RWT. Overall, this study reveals that this model development can effectuate future research with state-of-the-art urban climate models to further explore the benefits of vegetated biofiltration systems as a water sensitive urban design tool optimised with an urban irrigation system to maintain healthy vegetation.

  15. Excellent approach to modeling urban expansion by fuzzy cellular automata: agent base model

    Science.gov (United States)

    Khajavigodellou, Yousef; Alesheikh, Ali A.; Mohammed, Abdulrazak A. S.; Chapi, Kamran

    2014-09-01

    Recently, the interaction between humans and their environment is the one of important challenges in the world. Landuse/ cover change (LUCC) is a complex process that includes actors and factors at different social and spatial levels. The complexity and dynamics of urban systems make the applicable practice of urban modeling very difficult. With the increased computational power and the greater availability of spatial data, micro-simulation such as the agent based and cellular automata simulation methods, has been developed by geographers, planners, and scholars, and it has shown great potential for representing and simulating the complexity of the dynamic processes involved in urban growth and land use change. This paper presents Fuzzy Cellular Automata in Geospatial Information System and remote Sensing to simulated and predicted urban expansion pattern. These FCA-based dynamic spatial urban models provide an improved ability to forecast and assess future urban growth and to create planning scenarios, allowing us to explore the potential impacts of simulations that correspond to urban planning and management policies. A fuzzy inference guided cellular automata approach. Semantic or linguistic knowledge on Land use change is expressed as fuzzy rules, based on which fuzzy inference is applied to determine the urban development potential for each pixel. The model integrates an ABM (agent-based model) and FCA (Fuzzy Cellular Automata) to investigate a complex decision-making process and future urban dynamic processes. Based on this model rapid development and green land protection under the influences of the behaviors and decision modes of regional authority agents, real estate developer agents, resident agents and non- resident agents and their interactions have been applied to predict the future development patterns of the Erbil metropolitan region.

  16. 41 CFR 301-10.420 - When may I use a taxi, shuttle service or other courtesy transportation?

    Science.gov (United States)

    2010-07-01

    ..., shuttle service or other courtesy transportation? 301-10.420 Section 301-10.420 Public Contracts and... Courtesy Transportation § 301-10.420 When may I use a taxi, shuttle service or other courtesy... other courtesy transportation (if charges result), in the following manner: (1) At your official station...

  17. Urban meteorological modelling for nuclear emergency preparedness

    International Nuclear Information System (INIS)

    Baklanov, Alexander; Sorensen, Jens Havskov; Hoe, Steen Cordt; Amstrup, Bjarne

    2006-01-01

    The main objectives of the current EU project 'Integrated Systems for Forecasting Urban Meteorology, Air Pollution and Population Exposure' (FUMAPEX) are the improvement of meteorological forecasts for urban areas, the connection of numerical weather prediction (NWP) models to urban air pollution and population dose models, the building of improved urban air quality information and forecasting systems, and their application in cities in various European climates. In addition to the forecast of the worst air-pollution episodes in large cities, the potential use of improved weather forecasts for nuclear emergency management in urban areas, in case of hazardous releases from nuclear accidents or terror acts, is considered. Such use of NWP data is tested for the Copenhagen metropolitan area and the Oresund region. The Danish Meteorological Institute (DMI) is running an experimental version of the HIRLAM NWP model over Zealand including the Copenhagen metropolitan area with a horizontal resolution of 1.4 km, thus approaching the city-scale. This involves 1-km resolution physiographic data with implications for the urban surface parameters, e.g. surface fluxes, roughness length and albedo. For the city of Copenhagen, the enhanced high-resolution NWP forecasting will be provided to demonstrate the improved dispersion forecasting capabilities of the Danish nuclear emergency preparedness decision-support system, the Accident Reporting and Guidance Operational System (ARGOS), used by the Danish Emergency Management Agency (DEMA). Recently, ARGOS has been extended with a capability of real-time calculation of regional-scale atmospheric dispersion of radioactive material from accidental releases. This is effectuated through on-line interfacing with the Danish Emergency Response Model of the Atmosphere (DERMA), which is run at DMI. For local-scale modelling of atmospheric dispersion, ARGOS utilises the Local-Scale Model Chain (LSMC), which makes use of high-resolution DMI

  18. 3D Urban Virtual Models generation methodology for smart cities

    Directory of Open Access Journals (Sweden)

    M. Álvarez

    2018-04-01

    Full Text Available Currently the use of Urban 3D Models goes beyond the mere support of three-dimensional image for the visualization of our urban surroundings. The three-dimensional Urban Models are in themselves fundamental tools to manage the different phenomena that occur in smart cities. It is therefore necessary to generate realistic models, in which BIM building design information can be integrated with GIS and other space technologies. The generation of 3D Urban Models benefit from the amount of data from sensors with the latest technologies such as airborne sensors and of the existence of international standards such as CityGML. This paper presents a methodology for the development of a three - dimensional Urban Model, based on LiDAR data and the CityGML standard, applied to the city of Lorca.

  19. Characterization Urban Heat Island Effect and Modelling of Secondary Pollutant Formations at Urban Hotspots

    Science.gov (United States)

    Undi, G. S. N. V. K. S. N. S.

    2017-12-01

    More than 60 percent of the world population is living the urban zones by 2020. This socio of economic transformations will bring considerable changes to the ambient atmosphere. More than 70 percent of the air pollutants in the urban hotspots are from vehicular emissions. in the urban hotspots. In the urban hotspots, the meteorological and dispersion conditions will have different characteristics than in surrounding rural areas. Reactive pollutants transformations are drastically influenced by the local meteorological conditions. The complexity of urban structure alters the pollutants dispersion in the hotspots. This relationship between urban meteorology and air pollution is an important aspect of consideration. In the atmosphere, drastic changes have been noticed from micro to regional and global scales. However, the characteristics of air pollutant emissions vary with time and space, favorable dispersion conditions transport them from local to regional scale. In the present study, the impact of land cover change on Urban Heat Island effect (UHI) has been characterized by considering the three different zones with varying land use patterns. An attempt has been made to estimate the impact of UHI on secondary pollutants (O3) transformations. Envi-Met model has been used to characterize the UHI intensity for the selected zones. Meteorological and air quality measurements were carried out at the selected locations. The diurnal variations of Ozone (O3) concentration for three zones are correlated with the UHI intensity. And the monitoring and model results of O3 concentrations are in good agreement. It is observed from the obtained model results that the metrological parameters influence on local air quality is significant in urban zones.

  20. Modeling urban building energy use: A review of modeling approaches and procedures

    Energy Technology Data Exchange (ETDEWEB)

    Li, Wenliang; Zhou, Yuyu; Cetin, Kristen; Eom, Jiyong; Wang, Yu; Chen, Gang; Zhang, Xuesong

    2017-12-01

    With rapid urbanization and economic development, the world has been experiencing an unprecedented increase in energy consumption and greenhouse gas (GHG) emissions. While reducing energy consumption and GHG emissions is a common interest shared by major developed and developing countries, actions to enable these global reductions are generally implemented at the city scale. This is because baseline information from individual cities plays an important role in identifying economical options for improving building energy efficiency and reducing GHG emissions. Numerous approaches have been proposed for modeling urban building energy use in the past decades. This paper aims to provide an up-to-date review of the broad categories of energy models for urban buildings and describes the basic workflow of physics-based, bottom-up models and their applications in simulating urban-scale building energy use. Because there are significant differences across models with varied potential for application, strengths and weaknesses of the reviewed models are also presented. This is followed by a discussion of challenging issues associated with model preparation and calibration.

  1. Combining multimedia models with integrated urban water system models for micropollutants

    DEFF Research Database (Denmark)

    De Keyser, W.; Gevaert, V.; Verdonck, F.

    2010-01-01

    Integrated urban water system (IUWS) modeling aims at assessing the quality of the surface water receiving the urban emissions through sewage treatment plants, combined sewer overflows (CSOS) and stormwater drainage systems However, some micropollutants tend to appear in more than one environmental...... medium (air, water, sediment, soil, groundwater, etc) In this work, a multimedia fate and transport model (MFTM) is "wrapped around" a dynamic IUWS model for organic micropollutants to enable integrated environmental assessment The combined model was tested on a hypothetical catchment using two scenarios...... on the one hand a reference scenario with a combined sewerage system and on the other hand a stormwater infiltration pond scenario, as an example of a sustainable urban drainage system (SUDS) A case for Bis(2-ethylhexyl) phthalate (DEHP) was simulated and resulted in reduced surface water concentrations...

  2. Levy-taxis: a novel search strategy for finding odor plumes in turbulent flow-dominated environments

    International Nuclear Information System (INIS)

    Pasternak, Zohar; Grasso, Frank W; Bartumeus, Frederic

    2009-01-01

    Locating chemical plumes in aquatic or terrestrial environments is important for many economic, conservation, security and health related human activities. The localization process is composed mainly of two phases: finding the chemical plume and then tracking it to its source. Plume tracking has been the subject of considerable study whereas plume finding has received little attention. We address here the latter issue, where the searching agent must find the plume in a region often many times larger than the plume and devoid of the relevant chemical cues. The probability of detecting the plume not only depends on the movements of the searching agent but also on the fluid mechanical regime, shaping plume intermittency in space and time; this is a basic, general problem when exploring for ephemeral resources (e.g. moving and/or concealing targets). Here we present a bio-inspired search strategy named Levy-taxis that, under certain conditions, located odor plumes significantly faster and with a better success rate than other search strategies such as Levy walks (LW), correlated random walks (CRW) and systematic zig-zag. These results are based on computer simulations which contain, for the first time ever, digitalized real-world water flow and chemical plume instead of their theoretical model approximations. Combining elements of LW and CRW, Levy-taxis is particularly efficient for searching in flow-dominated environments: it adaptively controls the stochastic search pattern using environmental information (i.e. flow) that is available throughout the course of the search and shows correlation with the source providing the cues. This strategy finds natural application in real-world search missions, both by humans and autonomous robots, since it accommodates the stochastic nature of chemical mixing in turbulent flows. In addition, it may prove useful in the field of behavioral ecology, explaining and predicting the movement patterns of various animals searching for food

  3. Levy-taxis: a novel search strategy for finding odor plumes in turbulent flow-dominated environments

    Energy Technology Data Exchange (ETDEWEB)

    Pasternak, Zohar; Grasso, Frank W [BioMimetic and Cognitive Robotics Laboratory, Department of Psychology, Brooklyn College, The City University of New York, 2900 Bedford Avenue, Brooklyn 11210, NY (United States); Bartumeus, Frederic [Department of Ecology and Evolutionary Biology and Princeton Environmental Institute, 106 Guyot Hall, Princeton University, Princeton 08544, NJ (United States)], E-mail: zpast@yahoo.com

    2009-10-30

    Locating chemical plumes in aquatic or terrestrial environments is important for many economic, conservation, security and health related human activities. The localization process is composed mainly of two phases: finding the chemical plume and then tracking it to its source. Plume tracking has been the subject of considerable study whereas plume finding has received little attention. We address here the latter issue, where the searching agent must find the plume in a region often many times larger than the plume and devoid of the relevant chemical cues. The probability of detecting the plume not only depends on the movements of the searching agent but also on the fluid mechanical regime, shaping plume intermittency in space and time; this is a basic, general problem when exploring for ephemeral resources (e.g. moving and/or concealing targets). Here we present a bio-inspired search strategy named Levy-taxis that, under certain conditions, located odor plumes significantly faster and with a better success rate than other search strategies such as Levy walks (LW), correlated random walks (CRW) and systematic zig-zag. These results are based on computer simulations which contain, for the first time ever, digitalized real-world water flow and chemical plume instead of their theoretical model approximations. Combining elements of LW and CRW, Levy-taxis is particularly efficient for searching in flow-dominated environments: it adaptively controls the stochastic search pattern using environmental information (i.e. flow) that is available throughout the course of the search and shows correlation with the source providing the cues. This strategy finds natural application in real-world search missions, both by humans and autonomous robots, since it accommodates the stochastic nature of chemical mixing in turbulent flows. In addition, it may prove useful in the field of behavioral ecology, explaining and predicting the movement patterns of various animals searching for food

  4. URBAN EFFICIENT ENERGY EVALUATION IN HIGH RESOLUTION URBAN AREAS BY USING ADAPTED WRF-UCM AND MICROSYS CFD MODELS

    Science.gov (United States)

    San Jose, R.; Perez, J. L.; Gonzalez, R. M.

    2009-12-01

    Urban metabolism modeling has advanced substantially during the last years due to the increased detail in mesoscale urban parameterization in meteorological mesoscale models and CFD numerical tools. Recently the implementation of the “urban canopy model” (UCM) into the WRF mesoscale meteorological model has produced a substantial advance on the understanding of the urban atmospheric heat flux exchanges in the urban canopy. The need to optimize the use of heat energy in urban environment has produced a substantial increase in the detailed investigation of the urban heat flux exchanges. In this contribution we will show the performance of using a tool called MICROSYS (MICRO scale CFD modelling SYStem) which is an adaptation of the classical urban canopy model but on a high resolution environment by using a classical CFD approach. The energy balance in the urban system can be determined in a micrometeorologicl sense by considering the energy flows in and out of a control volume. For such a control volume reaching from ground to a certain height above buildings, the energy balance equation includes the net radiation, the anthropogenic heat flux, the turbulent sensible heat flux, the turbulent latent heat flux, the net storage change within the control volume, the net advected flux and other sources and sinks. We have applied the MICROSYS model to an area of 5 km x 5 km with 200 m spatial resolution by using the WRF-UCM (adapted and the MICROSYS CFD model. The anthropogenic heat flux has been estimated by using the Flanner M.G. (2009) database and detailed GIS information (50 m resolution) of Madrid city. The Storage energy has been estimated by calculating the energy balance according to the UCM procedure and implementing it into the MICROSYS tool. Results show that MICROSYS can be used as an energy efficient tool to estimate the energy balance of different urban areas and buildings.

  5. Large urban fire environment: trends and model city predictions

    International Nuclear Information System (INIS)

    Larson, D.A.; Small, R.D.

    1983-01-01

    The urban fire environment that would result from a megaton-yield nuclear weapon burst is considered. The dependence of temperatures and velocities on fire size, burning intensity, turbulence, and radiation is explored, and specific calculations for three model urban areas are presented. In all cases, high velocity fire winds are predicted. The model-city results show the influence of building density and urban sprawl on the fire environment. Additional calculations consider large-area fires with the burning intensity reduced in a blast-damaged urban center

  6. Urban contamination and dose model

    International Nuclear Information System (INIS)

    Robertson, E.; Barry, P.J.

    1995-10-01

    Nuclear power reactors and other nuclear facilities are being built near or even within urban centres. Accidental releases of radionuclides to the atmosphere in built-up areas result in radiological exposure pathways that differ from those caused by releases in rural environments. Other than inhalation, exposure pathways involve external radiation from the plume while it passes and from radioactivity deposited onto the many and varied surfaces after it has passed. Radiation fields inside buildings are attenuated but many people are potentially exposed so while individual doses may be relatively low, population integrated doses may be high enough to cause concern. It is important, therefore, to assess the potential exposures and to estimate the cost-effectiveness of dose reduction measures in urban environments. This report describes a model developed to carry out such assessments. The model draws heavily on experience gained in European cities after their contamination fallout from the Chernobyl accident. Input is time integrated concentrations of specific radionuclides in urban air, obtained either by direct measurement or by prediction using an atmospheric dispersion model. The code includes default values for site specific variables and transfer parameters but the user is invited if desired to enter other values from the keyboard. Output is the time integrated dose rates for individuals selected because of the characteristic living, working and recreational habits. An accompanying manual documents the technical background on which the model is based and leads a first-time suer through various steps and operations encountered while the model is running. (author). 60 refs., 10 tabs., 1 fig

  7. Assessing ecological sustainability in urban planning - EcoBalance model

    Energy Technology Data Exchange (ETDEWEB)

    Wahlgren, I., Email: irmeli.wahlgren@vtt.fi

    2012-06-15

    Urban planning solutions and decisions have large-scale significance for ecological sustainability (eco-efficiency) the consumption of energy and other natural resources, the production of greenhouse gas and other emissions and the costs caused by urban form. Climate change brings new and growing challenges for urban planning. The EcoBalance model was developed to assess the sustainability of urban form and has been applied at various planning levels: regional plans, local master plans and detailed plans. The EcoBalance model estimates the total consumption of energy and other natural resources, the production of emissions and wastes and the costs caused directly and indirectly by urban form on a life cycle basis. The results of the case studies provide information about the ecological impacts of various solutions in urban development. (orig.)

  8. Socio-Environmental Resilience and Complex Urban Systems Modeling

    Science.gov (United States)

    Deal, Brian; Petri, Aaron; Pan, Haozhi; Goldenberg, Romain; Kalantari, Zahra; Cvetkovic, Vladimir

    2017-04-01

    The increasing pressure of climate change has inspired two normative agendas; socio-technical transitions and socio-ecological resilience, both sharing a complex-systems epistemology (Gillard et al. 2016). Socio-technical solutions include a continuous, massive data gathering exercise now underway in urban places under the guise of developing a 'smart'(er) city. This has led to the creation of data-rich environments where large data sets have become central to monitoring and forming a response to anomalies. Some have argued that these kinds of data sets can help in planning for resilient cities (Norberg and Cumming 2008; Batty 2013). In this paper, we focus on a more nuanced, ecologically based, socio-environmental perspective of resilience planning that is often given less consideration. Here, we broadly discuss (and model) the tightly linked, mutually influenced, social and biophysical subsystems that are critical for understanding urban resilience. We argue for the need to incorporate these sub system linkages into the resilience planning lexicon through the integration of systems models and planning support systems. We make our case by first providing a context for urban resilience from a socio-ecological and planning perspective. We highlight the data needs for this type of resilient planning and compare it to currently collected data streams in various smart city efforts. This helps to define an approach for operationalizing socio-environmental resilience planning using robust systems models and planning support systems. For this, we draw from our experiences in coupling a spatio-temporal land use model (the Landuse Evolution and impact Assessment Model (LEAM)) with water quality and quantity models in Stockholm Sweden. We describe the coupling of these systems models using a robust Planning Support System (PSS) structural framework. We use the coupled model simulations and PSS to analyze the connection between urban land use transformation (social) and water

  9. Modeling Urban Spatial Growth in Mountainous Regions of Western China

    Directory of Open Access Journals (Sweden)

    Guoping Huang

    2017-08-01

    Full Text Available The scale and speed of urbanization in the mountainous regions of western China have received little attention from researchers. These cities are facing rapid population growth and severe environmental degradation. This study analyzed historical urban growth trends in this mountainous region to better understand the interaction between the spatial growth pattern and the mountainous topography. Three major factors—slope, accessibility, and land use type—were studied in light of their relationships with urban spatial growth. With the analysis of historical data as the basis, a conceptual urban spatial growth model was devised. In this model, slope, accessibility, and land use type together create resistance to urban growth, while accessibility controls the sequence of urban development. The model was tested and evaluated using historical data. It serves as a potential tool for planners to envision and assess future urban growth scenarios and their potential environmental impacts to make informed decisions.

  10. Urbancontext: A Management Model For Pervasive Environments In User-Oriented Urban Computing

    Directory of Open Access Journals (Sweden)

    Claudia L. Zuniga-Canon

    2014-01-01

    Full Text Available Nowadays, urban computing has gained a lot of interest for guiding the evolution of citiesinto intelligent environments. These environments are appropriated for individuals’ inter-actions changing in their behaviors. These changes require new approaches that allow theunderstanding of how urban computing systems should be modeled.In this work we present UrbanContext, a new model for designing of urban computingplatforms that applies the theory of roles to manage the individual’s context in urban envi-ronments. The theory of roles helps to understand the individual’s behavior within a socialenvironment, allowing to model urban computing systems able to adapt to individuals statesand their needs.UrbanContext collects data in urban atmospheres and classifies individuals’ behaviorsaccording to their change of roles, to optimize social interaction and offer secure services.Likewise, UrbanContext serves as a generic model to provide interoperability, and to facilitatethe design, implementation and expansion of urban computing systems.

  11. A new framework for modeling urban land expansion in peri-urban area by combining multi-source datasets and data assimilation

    Science.gov (United States)

    Zhang, Z.; Xiao, R.; Li, X.

    2015-12-01

    Peri-urban area is a new type region under the impacts of both rural Industrialization and the radiation of metropolitan during rapid urbanization. Due to its complex natural and social characteristics and unique development patterns, many problems such as environmental pollution and land use waste emerged, which became an urgent issue to be addressed. Study area in this paper covers three typical peri-urban districts (Pudong, Fengxian and Jinshan), which around the Shanghai inner city. By coupling cellular automata and multi-agent system model as the basic tools, this research focus on modelling the urban land expansion and driving mechanism in peri-urban area. The big data is aslo combined with the Bayesian maximum entropy method (BME) for spatiotemporal prediction of multi-source data, which expand the dataset of urban expansion models. Data assimilation method is used to optimize the parameters of the coupling model and minimize the uncertainty of observations, improving the precision of future simulation in peri-urban area. By setting quantitative parameters, the coupling model can effectively improve the simulation of the process of urban land expansion under different policies and management schemes, in order to provide scientificimplications for new urbanization strategy. In this research, we precise the urban land expansion simulation and prediction for peri-urban area, expand the scopes and selections of data acquisition measurements and methods, develop the new applications of the data assimilation method in geographical science, provide a new idea for understanding the inherent rules of urban land expansion, and give theoretical and practical support for the peri-urban area in urban planning and decision making.

  12. pH-Taxis of Biohybrid Microsystems

    Science.gov (United States)

    Zhuang, Jiang; Wright Carlsen, Rika; Sitti, Metin

    2015-06-01

    The last decade has seen an increasing number of studies developing bacteria and other cell-integrated biohybrid microsystems. However, the highly stochastic motion of these microsystems severely limits their potential use. Here, we present a method that exploits the pH sensing of flagellated bacteria to realize robust drift control of multi-bacteria propelled microrobots. Under three specifically configured pH gradients, we demonstrate that the microrobots exhibit both unidirectional and bidirectional pH-tactic behaviors, which are also observed in free-swimming bacteria. From trajectory analysis, we find that the swimming direction and speed biases are two major factors that contribute to their tactic drift motion. The motion analysis of microrobots also sheds light on the propulsion dynamics of the flagellated bacteria as bioactuators. It is expected that similar driving mechanisms are shared among pH-taxis, chemotaxis, and thermotaxis. By identifying the mechanism that drives the tactic behavior of bacteria-propelled microsystems, this study opens up an avenue towards improving the control of biohybrid microsystems. Furthermore, assuming that it is possible to tune the preferred pH of bioactuators by genetic engineering, these biohybrid microsystems could potentially be applied to sense the pH gradient induced by cancerous cells in stagnant fluids inside human body and realize targeted drug delivery.

  13. Injuries and absenteeism among motorcycle taxi drivers who are victims of traffic accidents.

    Science.gov (United States)

    Barbosa, Kevan G N; Lucas-Neto, Alfredo; Gama, Bruno D; Lima-Neto, Jose C; Lucas, Rilva Suely C C; d'Ávila, Sérgio

    2014-08-01

    Facial injuries frequently occur in traffic accidents involving motorcycles. The purpose of this study was to determine the prevalence of facial injuries among motorcycle drivers who perform motorcycle taxi service. The study design was cross-sectional. A total of 210 participants who served as motorcycle taxi drivers in a city in northeastern Brazil completed a survey concerning their experience of accidents involving facial injuries and consequent hospitalization and absenteeism from work. The motorcycle drivers included in the study were randomly selected from a list provided by the city. Out of the respondents, 165 (78.6%) who were involved in traffic accidents in the last 12 months, 15 (9.1%) reported facial injuries. The types of facial injury most frequently reported involved soft tissues (n = 8; 53.3%), followed by simple fracture (n = 4; 26.7%) and dentoalveolar fracture (n = 3; 20%). We found an association between facial injuries and absenteeism, as well as an association between the presence of facial injury and the need for hospitalization for a period of 2 days or more. Respondents reported that they had accidents, but due to the use of full face motorcycle helmet the number of facial injuries was low. For most of them, absenteeism was observed for a period of one month or more. Copyright © 2014 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

  14. Use of the renewable wind and photovoltaic sources, for the recharge of a fleet of electric taxis in Havana, Cuba

    International Nuclear Information System (INIS)

    Sánchez Torres, Yamir

    2017-01-01

    Electrification of the transportation sector seems to be one of the alternatives in terms of restriction of pollutant from that sector. However, it is necessary to study the GHG (Green House Gas) emissions from Generation Power Plants (EGPP) because could be more or less the same of that from the vehicles. Furthermore, Centralized GPP supply would result in distribution losses, bigger fuel consumption and more pollution. Thus, EVs development should be considered as a sustainable solution if powered by electricity systems with considerable share of Renewable Energy Sources (RES). In this paper, the study of the recharge of an EV taxi fleet during night, using photovoltaic and wind mills RES in Havana, Cuba, is analyzed. This work is aiming to find a feasible operational synergy between cited intermittent RES electricity generation and EVs taxi fleet recharge. (author)

  15. Modeling urbanized watershed flood response changes with distributed hydrological model: key hydrological processes, parameterization and case studies

    Science.gov (United States)

    Chen, Y.

    2017-12-01

    Urbanization is the world development trend for the past century, and the developing countries have been experiencing much rapider urbanization in the past decades. Urbanization brings many benefits to human beings, but also causes negative impacts, such as increasing flood risk. Impact of urbanization on flood response has long been observed, but quantitatively studying this effect still faces great challenges. For example, setting up an appropriate hydrological model representing the changed flood responses and determining accurate model parameters are very difficult in the urbanized or urbanizing watershed. In the Pearl River Delta area, rapidest urbanization has been observed in China for the past decades, and dozens of highly urbanized watersheds have been appeared. In this study, a physically based distributed watershed hydrological model, the Liuxihe model is employed and revised to simulate the hydrological processes of the highly urbanized watershed flood in the Pearl River Delta area. A virtual soil type is then defined in the terrain properties dataset, and its runoff production and routing algorithms are added to the Liuxihe model. Based on a parameter sensitive analysis, the key hydrological processes of a highly urbanized watershed is proposed, that provides insight into the hydrological processes and for parameter optimization. Based on the above analysis, the model is set up in the Songmushan watershed where there is hydrological data observation. A model parameter optimization and updating strategy is proposed based on the remotely sensed LUC types, which optimizes model parameters with PSO algorithm and updates them based on the changed LUC types. The model parameters in Songmushan watershed are regionalized at the Pearl River Delta area watersheds based on the LUC types of the other watersheds. A dozen watersheds in the highly urbanized area of Dongguan City in the Pearl River Delta area were studied for the flood response changes due to

  16. MODELING URBAN DYNAMICS USING RANDOM FOREST: IMPLEMENTING ROC AND TOC FOR MODEL EVALUATION

    Directory of Open Access Journals (Sweden)

    M. Ahmadlou

    2016-06-01

    Full Text Available The importance of spatial accuracy of land use/cover change maps necessitates the use of high performance models. To reach this goal, calibrating machine learning (ML approaches to model land use/cover conversions have received increasing interest among the scholars. This originates from the strength of these techniques as they powerfully account for the complex relationships underlying urban dynamics. Compared to other ML techniques, random forest has rarely been used for modeling urban growth. This paper, drawing on information from the multi-temporal Landsat satellite images of 1985, 2000 and 2015, calibrates a random forest regression (RFR model to quantify the variable importance and simulation of urban change spatial patterns. The results and performance of RFR model were evaluated using two complementary tools, relative operating characteristics (ROC and total operating characteristics (TOC, by overlaying the map of observed change and the modeled suitability map for land use change (error map. The suitability map produced by RFR model showed 82.48% area under curve for the ROC model which indicates a very good performance and highlights its appropriateness for simulating urban growth.

  17. Micro-meteorological modelling in urban areas: pollutant dispersion and radiative effects modelling

    International Nuclear Information System (INIS)

    Milliez, Maya

    2006-01-01

    Atmospheric pollution and urban climate studies require to take into account the complex processes due to heterogeneity of urban areas and the interaction with the buildings. In order to estimate the impact of buildings on flow and pollutant dispersion, detailed numerical simulations were performed over an idealized urban area, with the three-dimensional model Mercure-Saturne, modelling both concentration means and their fluctuations. To take into account atmospheric radiation in built up areas and the thermal effects of the buildings, we implemented a three-dimensional radiative model adapted to complex geometry. This model, adapted from a scheme used for thermal radiation, solves the radiative transfer equation in a semi-transparent media, using the discrete ordinate method. The new scheme was validated with idealized cases and compared to a complete case. (author) [fr

  18. Urban drainage models - making uncertainty analysis simple

    DEFF Research Database (Denmark)

    Vezzaro, Luca; Mikkelsen, Peter Steen; Deletic, Ana

    2012-01-01

    in each measured/observed datapoint; an issue which is commonly overlook in the uncertainty analysis of urban drainage models. This comparison allows the user to intuitively estimate the optimum number of simulations required to conduct uncertainty analyses. The output of the method includes parameter......There is increasing awareness about uncertainties in modelling of urban drainage systems and, as such, many new methods for uncertainty analyses have been developed. Despite this, all available methods have limitations which restrict their widespread application among practitioners. Here...

  19. First results from the International Urban Energy Balance Model Comparison: Model Complexity

    Science.gov (United States)

    Blackett, M.; Grimmond, S.; Best, M.

    2009-04-01

    A great variety of urban energy balance models has been developed. These vary in complexity from simple schemes that represent the city as a slab, through those which model various facets (i.e. road, walls and roof) to more complex urban forms (including street canyons with intersections) and features (such as vegetation cover and anthropogenic heat fluxes). Some schemes also incorporate detailed representations of momentum and energy fluxes distributed throughout various layers of the urban canopy layer. The models each differ in the parameters they require to describe the site and the in demands they make on computational processing power. Many of these models have been evaluated using observational datasets but to date, no controlled comparisons have been conducted. Urban surface energy balance models provide a means to predict the energy exchange processes which influence factors such as urban temperature, humidity, atmospheric stability and winds. These all need to be modelled accurately to capture features such as the urban heat island effect and to provide key information for dispersion and air quality modelling. A comparison of the various models available will assist in improving current and future models and will assist in formulating research priorities for future observational campaigns within urban areas. In this presentation we will summarise the initial results of this international urban energy balance model comparison. In particular, the relative performance of the models involved will be compared based on their degree of complexity. These results will inform us on ways in which we can improve the modelling of air quality within, and climate impacts of, global megacities. The methodology employed in conducting this comparison followed that used in PILPS (the Project for Intercomparison of Land-Surface Parameterization Schemes) which is also endorsed by the GEWEX Global Land Atmosphere System Study (GLASS) panel. In all cases, models were run

  20. Urban weather data and building models for the inclusion of the urban heat island effect in building performance simulation.

    Science.gov (United States)

    Palme, M; Inostroza, L; Villacreses, G; Lobato, A; Carrasco, C

    2017-10-01

    This data article presents files supporting calculation for urban heat island (UHI) inclusion in building performance simulation (BPS). Methodology is used in the research article "From urban climate to energy consumption. Enhancing building performance simulation by including the urban heat island effect" (Palme et al., 2017) [1]. In this research, a Geographical Information System (GIS) study is done in order to statistically represent the most important urban scenarios of four South-American cities (Guayaquil, Lima, Antofagasta and Valparaíso). Then, a Principal Component Analysis (PCA) is done to obtain reference Urban Tissues Categories (UTC) to be used in urban weather simulation. The urban weather files are generated by using the Urban Weather Generator (UWG) software (version 4.1 beta). Finally, BPS is run out with the Transient System Simulation (TRNSYS) software (version 17). In this data paper, four sets of data are presented: 1) PCA data (excel) to explain how to group different urban samples in representative UTC; 2) UWG data (text) to reproduce the Urban Weather Generation for the UTC used in the four cities (4 UTC in Lima, Guayaquil, Antofagasta and 5 UTC in Valparaíso); 3) weather data (text) with the resulting rural and urban weather; 4) BPS models (text) data containing the TRNSYS models (four building models).

  1. Lévy-taxis: a novel search strategy for finding odor plumes in turbulent flow-dominated environments

    Science.gov (United States)

    Pasternak, Zohar; Bartumeus, Frederic; Grasso, Frank W.

    2009-10-01

    Locating chemical plumes in aquatic or terrestrial environments is important for many economic, conservation, security and health related human activities. The localization process is composed mainly of two phases: finding the chemical plume and then tracking it to its source. Plume tracking has been the subject of considerable study whereas plume finding has received little attention. We address here the latter issue, where the searching agent must find the plume in a region often many times larger than the plume and devoid of the relevant chemical cues. The probability of detecting the plume not only depends on the movements of the searching agent but also on the fluid mechanical regime, shaping plume intermittency in space and time; this is a basic, general problem when exploring for ephemeral resources (e.g. moving and/or concealing targets). Here we present a bio-inspired search strategy named Lévy-taxis that, under certain conditions, located odor plumes significantly faster and with a better success rate than other search strategies such as Lévy walks (LW), correlated random walks (CRW) and systematic zig-zag. These results are based on computer simulations which contain, for the first time ever, digitalized real-world water flow and chemical plume instead of their theoretical model approximations. Combining elements of LW and CRW, Lévy-taxis is particularly efficient for searching in flow-dominated environments: it adaptively controls the stochastic search pattern using environmental information (i.e. flow) that is available throughout the course of the search and shows correlation with the source providing the cues. This strategy finds natural application in real-world search missions, both by humans and autonomous robots, since it accomodates the stochastic nature of chemical mixing in turbulent flows. In addition, it may prove useful in the field of behavioral ecology, explaining and predicting the movement patterns of various animals searching for

  2. Accesibilidad en el transporte público en Valladolid ferrocarril, autobús y taxi

    OpenAIRE

    Díez Peña, Mª Begoña; Herrero Rodríguez, Sonia

    2015-01-01

    El objetivo de este trabajo es conocer la medida en la que se cumple la normativa de accesibilidad al transporte público en la ciudad de Valladolid, en concreto ferrocarril, autobús y taxi, no sólo en el sentido estricto de la normativa sino también desde el punto de vista de la autonomía de una persona con discapacidad física. Departamento de Organización de Empresas y Comercialización e Investigación de Mercados Máster en Logística

  3. Cooperating Mobile GIS and Wireless Sensor Networks for Managing Transportation Infrastructures in Urban areas

    Directory of Open Access Journals (Sweden)

    R. Shad

    2013-10-01

    Full Text Available Time management is a major subject which, in order to optimize trip conditions, emphasizes on interpreting processes and classifying individual's information. In this paper, with the aim of providing an optimal system for urban commuting in proper time in Mashhad, each user using SMS and introducing some of his/her mental priorities to the system, will be able to select the best option depending on the timing of movement of the available public transport system. The present study adopts a newly developed method of time management which is evaluated for urban transportation considering dynamic conditions of a spatial database. For this purpose, regarding time management, processed data such as bus lines, taxi networks, and the subway system are combined in a spatial framework of a designed Mobile GIS based on a wireless network. So, multiple potential paths which end to a desirable destination.

  4. URBAN MODELLING PERFORMANCE OF NEXT GENERATION SAR MISSIONS

    Directory of Open Access Journals (Sweden)

    U. G. Sefercik

    2017-09-01

    Full Text Available In synthetic aperture radar (SAR technology, urban mapping and modelling have become possible with revolutionary missions TerraSAR-X (TSX and Cosmo-SkyMed (CSK since 2007. These satellites offer 1m spatial resolution in high-resolution spotlight imaging mode and capable for high quality digital surface model (DSM acquisition for urban areas utilizing interferometric SAR (InSAR technology. With the advantage of independent generation from seasonal weather conditions, TSX and CSK DSMs are much in demand by scientific users. The performance of SAR DSMs is influenced by the distortions such as layover, foreshortening, shadow and double-bounce depend up on imaging geometry. In this study, the potential of DSMs derived from convenient 1m high-resolution spotlight (HS InSAR pairs of CSK and TSX is validated by model-to-model absolute and relative accuracy estimations in an urban area. For the verification, an airborne laser scanning (ALS DSM of the study area was used as the reference model. Results demonstrated that TSX and CSK urban DSMs are compatible in open, built-up and forest land forms with the absolute accuracy of 8–10 m. The relative accuracies based on the coherence of neighbouring pixels are superior to absolute accuracies both for CSK and TSX.

  5. The effect of navigational expertise on wayfinding in new environments.

    Science.gov (United States)

    Woollett, Katherine; Maguire, Eleanor A

    2010-12-01

    Becoming proficient at navigation in urban environments is something that we all aspire to. Here we asked whether being an expert at wayfinding in one environment has any effect on learning new spatial layouts. Licensed London taxi drivers are among the most proficient urban navigators, training for many years to find their way around a complex and irregularly-laid out city. We first tested how well they could learn the layout of an unfamiliar town compared with a group of non-taxi drivers. Second, we investigated how effectively taxi drivers could integrate a new district into their existing spatial representation of London. We found that taxi drivers were significantly better than control participants at executing routes through the new town, and representing it at a map-like survey level. However, the benefits of navigational expertise were not universal. Compared with their performance in the new town, taxi drivers were significantly poorer at learning the layout of a new area that had to be integrated with their existing knowledge of London. We consider reasons for this picture of facilitation and limitation, in particular drawing parallels with how knowledge acquisition occurs in the context of expertise in general.

  6. Research on application of intelligent computation based LUCC model in urbanization process

    Science.gov (United States)

    Chen, Zemin

    2007-06-01

    Global change study is an interdisciplinary and comprehensive research activity with international cooperation, arising in 1980s, with the largest scopes. The interaction between land use and cover change, as a research field with the crossing of natural science and social science, has become one of core subjects of global change study as well as the front edge and hot point of it. It is necessary to develop research on land use and cover change in urbanization process and build an analog model of urbanization to carry out description, simulation and analysis on dynamic behaviors in urban development change as well as to understand basic characteristics and rules of urbanization process. This has positive practical and theoretical significance for formulating urban and regional sustainable development strategy. The effect of urbanization on land use and cover change is mainly embodied in the change of quantity structure and space structure of urban space, and LUCC model in urbanization process has been an important research subject of urban geography and urban planning. In this paper, based upon previous research achievements, the writer systematically analyzes the research on land use/cover change in urbanization process with the theories of complexity science research and intelligent computation; builds a model for simulating and forecasting dynamic evolution of urban land use and cover change, on the basis of cellular automation model of complexity science research method and multi-agent theory; expands Markov model, traditional CA model and Agent model, introduces complexity science research theory and intelligent computation theory into LUCC research model to build intelligent computation-based LUCC model for analog research on land use and cover change in urbanization research, and performs case research. The concrete contents are as follows: 1. Complexity of LUCC research in urbanization process. Analyze urbanization process in combination with the contents

  7. Personal exposures to airborne metals in London taxi drivers and office workers in 1995 and 1996

    Energy Technology Data Exchange (ETDEWEB)

    Pfeifer, G.D.; Lynam, D.R. [Air Conservation Department, Ethyl Corporation, 330 South Fourth Street, Richmond, VA (United States); Harrison, R.M. [The University of Birmingham, Environmental Health, School of Chemistry, Edgbaston, Birmingham (United Kingdom)

    1999-09-01

    In 1995, a petroleum marketer introduced a diesel fuel additive in the UK containing Mn as MMT (methylcyclopentadienyl manganese tricarbonyl). A small study of personal exposures to airborne Mn in London was conducted before and after introduction of the additive to identify any major impact of the additive on exposures. In 1995, personal exposures to Mn were measured in two groups, taxi drivers and office workers (10 subjects per group) for two consecutive 7-day periods. A similar study was carried out in 1996 to determine if exposures had changed. Samples were also analyzed for Ca, Al, Mg and Pb. In 1996, exposures to aerosol mass as total suspended particulates (TSP) and PM{sub 2.5} were measured in addition to the metals. Manganese exposures in this cohort did not increase as a result of introduction of the additive. However, a significant source of Mn exposure was discovered during the conduct of these tests. The mean exposure to Mn was higher among the office workers in both years than that of the taxi drivers. This was due to the fact that approximately half the office workers commuted via the underground railway system where airborne dust and metal concentrations are significantly elevated over those in the general environment. Similar results have been noted in other cities having underground rail systems. Exposure to Mn, Pb, Ca, and Mg were not significantly different between the 2 years. Taxi drivers had higher exposures than office workers to Mg and Pb in both years. Commuting via the underground also had a significant impact on exposures to TSP, PM{sub 2.5}, Al, and Ca, but had little effect on exposures to Mg. The aerosol in the underground was particularly enriched in Mn, approximately 10-fold, when compared to the aerosol in the general environment. There are several possible sources for this Mn, including mechanical wear of the steel wheels on the steel rails, vaporization of metal from sparking of the third rail, or brake wear.

  8. Vehicle-based interactive management with multi-agent approach

    Directory of Open Access Journals (Sweden)

    Yee Ming Chen

    2009-09-01

    Full Text Available Under the energy crisis and global warming, mass transportation becomes more important than before. The disadvantages of mass transportation, plus the high flexibility and efficiency of taxi and with the revolution of technology, electric-taxi is the better transportation choice for metropolis. On the other hand, among the many taxi service types, dial-a-ride (DAR service system is the better way for passenger and taxi. However the electricity replenishing of electric-taxi is the biggest shortage and constraint for DAR operation system. In order to more effectively manage the electric-taxi DAR operation system and the lots of disadvantages of physical system and observe the behaviors and interactions of simulation system, multi-agent simulation technique is the most suitable simulation technique. Finally, we use virtual data as the input of simulation system and analyze the simulation result. We successfully obtain two performance measures: average waiting time and service rate. Result shows the average waiting time is only 3.93 seconds and the service rate (total transport passenger number / total passenger number is 37.073%. So these two performance measures can support us to make management decisions. The multiagent oriented model put forward in this article is the subject of an application intended in the long term to supervise the user information system of an urban transport network.

  9. Applicability of models to estimate traffic noise for urban roads.

    Science.gov (United States)

    Melo, Ricardo A; Pimentel, Roberto L; Lacerda, Diego M; Silva, Wekisley M

    2015-01-01

    Traffic noise is a highly relevant environmental impact in cities. Models to estimate traffic noise, in turn, can be useful tools to guide mitigation measures. In this paper, the applicability of models to estimate noise levels produced by a continuous flow of vehicles on urban roads is investigated. The aim is to identify which models are more appropriate to estimate traffic noise in urban areas since several models available were conceived to estimate noise from highway traffic. First, measurements of traffic noise, vehicle count and speed were carried out in five arterial urban roads of a brazilian city. Together with geometric measurements of width of lanes and distance from noise meter to lanes, these data were input in several models to estimate traffic noise. The predicted noise levels were then compared to the respective measured counterparts for each road investigated. In addition, a chart showing mean differences in noise between estimations and measurements is presented, to evaluate the overall performance of the models. Measured Leq values varied from 69 to 79 dB(A) for traffic flows varying from 1618 to 5220 vehicles/h. Mean noise level differences between estimations and measurements for all urban roads investigated ranged from -3.5 to 5.5 dB(A). According to the results, deficiencies of some models are discussed while other models are identified as applicable to noise estimations on urban roads in a condition of continuous flow. Key issues to apply such models to urban roads are highlighted.

  10. Assessing the impacts of deploying a shared self-driving urban mobility system: An agent-based model applied to the city of Lisbon, Portugal

    Directory of Open Access Journals (Sweden)

    Luis M. Martinez

    2017-06-01

    Full Text Available This paper examines the changes that might result from the large-scale uptake of a shared and self-driving fleet of vehicles in a mid-sized European city. The work explores two different self-driving vehicle concepts – a ridesharing system (Shared Taxi, which emulates a taxi-like system where customers accept small detours from their original direct path and share part of their ride with others and a dynamic bus-like service with minibuses (Taxi-Bus, where customers pre-book their service at least 30 min in advance (permanent bookings for regular trips should represent most requests and walk short distances to a designated stop. Under the premise that the “upgraded” system should as much as possible deliver the same trips as today in terms of origin, destination and timing, and that it should also replace all car and bus trips, it looks at impacts on car fleet size, volume of travel and parking requirements. Mobility output and CO2 emissions are also detailed in two different time scales (24 h. average and peak-hour only. The obtained results suggest that a full implementation scenario where the existing metro service is kept and private car, bus and taxi mobility would be replaced by shared modes would significantly reduce travelled vehicle.kilometres and CO2 emissions.

  11. A data model for simulation models relying on spatio-temporal urban data

    OpenAIRE

    Langlois , G ,; Tourre , Vincent; Servières , Myriam; Gervais , G ,; Gesquière , Gilles

    2016-01-01

    International audience; To understand the complexity of modern cities and anticipate their expansion, experts from various fields conceive simulation models that can be very different. Those simulation models work with a variety of data with their own organization. Furthermore, because the urban objects are studied in the context of the evolution of a city or urban area, they carry temporal and spatial information. In this paper, we present the base classes of a common data model robust and f...

  12. Urban weather data and building models for the inclusion of the urban heat island effect in building performance simulation

    Directory of Open Access Journals (Sweden)

    M. Palme

    2017-10-01

    Full Text Available This data article presents files supporting calculation for urban heat island (UHI inclusion in building performance simulation (BPS. Methodology is used in the research article “From urban climate to energy consumption. Enhancing building performance simulation by including the urban heat island effect” (Palme et al., 2017 [1]. In this research, a Geographical Information System (GIS study is done in order to statistically represent the most important urban scenarios of four South-American cities (Guayaquil, Lima, Antofagasta and Valparaíso. Then, a Principal Component Analysis (PCA is done to obtain reference Urban Tissues Categories (UTC to be used in urban weather simulation. The urban weather files are generated by using the Urban Weather Generator (UWG software (version 4.1 beta. Finally, BPS is run out with the Transient System Simulation (TRNSYS software (version 17. In this data paper, four sets of data are presented: 1 PCA data (excel to explain how to group different urban samples in representative UTC; 2 UWG data (text to reproduce the Urban Weather Generation for the UTC used in the four cities (4 UTC in Lima, Guayaquil, Antofagasta and 5 UTC in Valparaíso; 3 weather data (text with the resulting rural and urban weather; 4 BPS models (text data containing the TRNSYS models (four building models.

  13. Uncertainty propagation in urban hydrology water quality modelling

    NARCIS (Netherlands)

    Torres Matallana, Arturo; Leopold, U.; Heuvelink, G.B.M.

    2016-01-01

    Uncertainty is often ignored in urban hydrology modelling. Engineering practice typically ignores uncertainties and uncertainty propagation. This can have large impacts, such as the wrong dimensioning of urban drainage systems and the inaccurate estimation of pollution in the environment caused

  14. Development of river flood model in lower reach of urbanized river basin

    Science.gov (United States)

    Yoshimura, Kouhei; Tajima, Yoshimitsu; Sanuki, Hiroshi; Shibuo, Yoshihiro; Sato, Shinji; Lee, SungAe; Furumai, Hiroaki; Koike, Toshio

    2014-05-01

    Japan, with its natural mountainous landscape, has demographic feature that population is concentrated in lower reach of elevation close to the coast, and therefore flood damage with large socio-economic value tends to occur in low-lying region. Modeling of river flood in such low-lying urbanized river basin is complex due to the following reasons. In upstream it has been experienced urbanization, which changed land covers from natural forest or agricultural fields to residential or industrial area. Hence rate of infiltration and runoff are quite different from natural hydrological settings. In downstream, paved covers and construct of sewerage system in urbanized areas affect direct discharges and it enhances higher and faster flood peak arrival. Also tidal effect from river mouth strongly affects water levels in rivers, which must be taken into account. We develop an integrated river flood model in lower reach of urbanized areas to be able to address above described complex feature, by integrating model components: LSM coupled distributed hydrological model that models anthropogenic influence on river discharges to downstream; urban hydrological model that simulates run off response in urbanized areas; Saint Venant's equation approximated river model that integrates upstream and urban hydrological models with considering tidal effect from downstream. These features are integrated in a common modeling framework so that model interaction can be directly performed. The model is applied to the Tsurumi river basin, urbanized low-lying river basin in Yokohama and model results show that it can simulate water levels in rivers with acceptable model errors. Furthermore the model is able to install miscellaneous water planning constructs, such as runoff reduction pond in urbanized area, flood control field along the river channel, levee, etc. This can be a useful tool to investigate cost performance of hypothetical water management plan against impact of climate change in

  15. Modelling atmospheric deposition flux of Cadmium and Lead in urban areas

    International Nuclear Information System (INIS)

    Cherin, Nicolas

    2017-01-01

    According to WHO, air pollution is responsible for more than 3.7 million premature deaths each year (OMS, 2014). Moreover, among these deaths, more than 70 within urban areas. Consequently, the health and environmental impacts of pollutants within these urban areas are of great concern in air quality studies. The deposition fluxes of air pollutants, which can be significant near sources of pollution, have rarely been modeled within urban areas. Historically, atmospheric deposition studies have focused mostly on remote areas to assess the potential impacts on ecosystems of acid deposition and nitrogen loading. Therefore, current atmospheric deposition models may not be suitable to simulate deposition fluxes in urban areas, which include complex surface geometries and diverse land use types. Atmospheric dry deposition is typically modeled using an average roughness length, which depends on land use. This classical roughness-length approach cannot account for the spatial variability of dry deposition in complex settings such as urban areas. Urban canopy models have been developed to parameterize momentum and heat transfer. We extend this approach here to mass transfer, and a new dry deposition model based on the urban canyon concept is presented. It uses a local mixing-length parameterization of turbulence within the canopy, and a description of the urban canopy via key parameters to provide spatially distributed dry deposition fluxes. This approach provides spatially distributed dry deposition fluxes depending on surfaces (streets, walls, roofs) and flow regimes (recirculation and ventilation) within the urban area. (author) [fr

  16. Analysis and Modeling of Ground Operations at Hub Airports

    Science.gov (United States)

    Atkins, Stephen (Technical Monitor); Andersson, Kari; Carr, Francis; Feron, Eric; Hall, William D.

    2000-01-01

    Building simple and accurate models of hub airports can considerably help one understand airport dynamics, and may provide quantitative estimates of operational airport improvements. In this paper, three models are proposed to capture the dynamics of busy hub airport operations. Two simple queuing models are introduced to capture the taxi-out and taxi-in processes. An integer programming model aimed at representing airline decision-making attempts to capture the dynamics of the aircraft turnaround process. These models can be applied for predictive purposes. They may also be used to evaluate control strategies for improving overall airport efficiency.

  17. Unified Data Model of Urban Air Pollution Dispersion and 3D Spatial City Models: Groundwork Assessment towards Sustainable Urban Development for Malaysia

    DEFF Research Database (Denmark)

    Ujang, Uznir; Anton, François; Rahman, Alias Abdul

    2013-01-01

    air pollution in urban areas encompasses sophisticated air quality modeling and data acquisition. However, rapid developments in major cities cause difficulties in acquiring the city geometries. The existing method in acquiring city geometries data via ground or space measurement inspection....... Therefore this paper aims is to perform groundwork assessment and discuss on the current scenario in Malaysia in the aspect of current policies towards SUD, air quality monitoring stations, scale model and detail discussion on air pollution dispersion model used called the Operational Street Pollution Model......Understanding the behavior of urban air pollution is important en route for sustainable urban development (SUD). Malaysia is on its mission to be a developed country by year 2020 comprehends dealing with air pollution is one of the indicators headed towards it. At present monitoring and managing...

  18. Statistical modeling of urban air temperature distributions under different synoptic conditions

    Science.gov (United States)

    Beck, Christoph; Breitner, Susanne; Cyrys, Josef; Hald, Cornelius; Hartz, Uwe; Jacobeit, Jucundus; Richter, Katja; Schneider, Alexandra; Wolf, Kathrin

    2015-04-01

    Within urban areas air temperature may vary distinctly between different locations. These intra-urban air temperature variations partly reach magnitudes that are relevant with respect to human thermal comfort. Therefore and furthermore taking into account potential interrelations with other health related environmental factors (e.g. air quality) it is important to estimate spatial patterns of intra-urban air temperature distributions that may be incorporated into urban planning processes. In this contribution we present an approach to estimate spatial temperature distributions in the urban area of Augsburg (Germany) by means of statistical modeling. At 36 locations in the urban area of Augsburg air temperatures are measured with high temporal resolution (4 min.) since December 2012. These 36 locations represent different typical urban land use characteristics in terms of varying percentage coverages of different land cover categories (e.g. impervious, built-up, vegetated). Percentage coverages of these land cover categories have been extracted from different sources (Open Street Map, European Urban Atlas, Urban Morphological Zones) for regular grids of varying size (50, 100, 200 meter horizonal resolution) for the urban area of Augsburg. It is well known from numerous studies that land use characteristics have a distinct influence on air temperature and as well other climatic variables at a certain location. Therefore air temperatures at the 36 locations are modeled utilizing land use characteristics (percentage coverages of land cover categories) as predictor variables in Stepwise Multiple Regression models and in Random Forest based model approaches. After model evaluation via cross-validation appropriate statistical models are applied to gridded land use data to derive spatial urban air temperature distributions. Varying models are tested and applied for different seasons and times of the day and also for different synoptic conditions (e.g. clear and calm

  19. Urbanization impacts on mammals across urban-forest edges and a predictive model of edge effects.

    Science.gov (United States)

    Villaseñor, Nélida R; Driscoll, Don A; Escobar, Martín A H; Gibbons, Philip; Lindenmayer, David B

    2014-01-01

    With accelerating rates of urbanization worldwide, a better understanding of ecological processes at the wildland-urban interface is critical to conserve biodiversity. We explored the effects of high and low-density housing developments on forest-dwelling mammals. Based on habitat characteristics, we expected a gradual decline in species abundance across forest-urban edges and an increased decline rate in higher contrast edges. We surveyed arboreal mammals in sites of high and low housing density along 600 m transects that spanned urban areas and areas turn on adjacent native forest. We also surveyed forest controls to test whether edge effects extended beyond our edge transects. We fitted models describing richness, total abundance and individual species abundance. Low-density housing developments provided suitable habitat for most arboreal mammals. In contrast, high-density housing developments had lower species richness, total abundance and individual species abundance, but supported the highest abundances of an urban adapter (Trichosurus vulpecula). We did not find the predicted gradual decline in species abundance. Of four species analysed, three exhibited no response to the proximity of urban boundaries, but spilled over into adjacent urban habitat to differing extents. One species (Petaurus australis) had an extended negative response to urban boundaries, suggesting that urban development has impacts beyond 300 m into adjacent forest. Our empirical work demonstrates that high-density housing developments have negative effects on both community and species level responses, except for one urban adapter. We developed a new predictive model of edge effects based on our results and the literature. To predict animal responses across edges, our framework integrates for first time: (1) habitat quality/preference, (2) species response with the proximity to the adjacent habitat, and (3) spillover extent/sensitivity to adjacent habitat boundaries. This framework will

  20. Speed, speed variation and crash relationships for urban arterials.

    Science.gov (United States)

    Wang, Xuesong; Zhou, Qingya; Quddus, Mohammed; Fan, Tianxiang; Fang, Shou'en

    2018-04-01

    Speed and speed variation are closely associated with traffic safety. There is, however, a dearth of research on this subject for the case of urban arterials in general, and in the context of developing nations. In downtown Shanghai, the traffic conditions in each direction are very different by time of day, and speed characteristics during peak hours are also greatly different from those during off-peak hours. Considering that traffic demand changes with time and in different directions, arterials in this study were divided into one-way segments by the direction of flow, and time of day was differentiated and controlled for. In terms of data collection, traditional fixed-based methods have been widely used in previous studies, but they fail to capture the spatio-temporal distributions of speed along a road. A new approach is introduced to estimate speed variation by integrating spatio-temporal speed fluctuation of a single vehicle with speed differences between vehicles using taxi-based high frequency GPS data. With this approach, this paper aims to comprehensively establish a relationship between mean speed, speed variation and traffic crashes for the purpose of formulating effective speed management measures, specifically using an urban dataset. From a total of 234 one-way road segments from eight arterials in Shanghai, mean speed, speed variation, geometric design features, traffic volume, and crash data were collected. Because the safety effects of mean speed and speed variation may vary at different segment lengths, arterials with similar signal spacing density were grouped together. To account for potential correlations among these segments, a hierarchical Poisson log-normal model with random effects was developed. Results show that a 1% increase in mean speed on urban arterials was associated with a 0.7% increase in total crashes, and larger speed variation was also associated with increased crash frequency. Copyright © 2018 Elsevier Ltd. All rights

  1. Procedural modeling of urban layout: population, land use, and road network

    OpenAIRE

    Lyu, X.; Han, Q.; de Vries, B.

    2017-01-01

    This paper introduces an urban simulation system generating urban layouts with population, road network and land use layers. The desired urban spatial structure is obtained by generating a population map based on population density models. The road network is generated at two spatial levels corresponding to the road hierarchy. The land use allocation is based on the What If? allocation model. The expected results are urban layouts suitable for academic scenario analysis.

  2. Availability, functionality, and use of seat belts in Beijing taxis prior to the 2008 Beijing Olympic Games.

    Science.gov (United States)

    Fleiter, Judy J; Gao, Liping; Qiu, Chen; Shi, Kan

    2009-03-01

    Use of driver seat belts and availability and functionality of passenger seat belts in a convenience sample of 231 Beijing taxis were examined in the months prior to the 2008 Beijing Olympic Games. Driver and front passenger seat belt use was mandated in China from 2004 to help address the growing public health crisis of road trauma. Results from observations made by in-vehicle passengers revealed that 21.2% of drivers were correctly wearing a belt, approximately half were not, and one third were using the belt in a non-functional way. Over 3/4 of this sample of taxi drivers were unrestrained while working. The percentage of functionally available belts was higher for front than rear passengers (88.3% and 22.9%, respectively). This low rate of belt availability in rear seats calls into question the preparedness of the fleet to cater for the safety needs of foreign visitors to China, particularly those from countries with high levels of restraint use. Factors influencing the use/misuse of seat belts in China remain largely unexplored. Results of this pilot study support further investigations of barriers to using injury prevention mechanisms such as seat belts in less motorised countries.

  3. Eco-Anthropic Compatibility - a Multidisciplinary Model in Urban Ecology

    Directory of Open Access Journals (Sweden)

    MARIANO L. BIANCA

    2010-01-01

    Full Text Available In this paper I propose a multidisciplinary model of urban development which goes beyond the notion of ecological sustainability, by building on the concept of eco-anthropic compatibility. First of all I will sketch the historical development of human aggregations and I will underline the difference between ancient and modern aggregations. On the basis of this analysis, I will take into consideration the notion of sustainability and its possible application to present conurbations. I will underline several limits of the notion of sustainable development and I will propose a multidisciplinary model grounded on a broader and new notion: the eco-anthropic compatibility. Using this notion, which includes the idea of sustainability, it is possible to handle, within the model, the human factors and human living conditions inside an urban aggregation. Finally, I will state that the actual urban model is decaying and therefore, sooner or later, we will have to face the end of urban civilization; for this reason we can start imagining new future ways for human aggregations on the planet based on the notion of eco-anthropic compatibility.

  4. Mass balance-based regression modeling of PAHs accumulation in urban soils, role of urban development

    International Nuclear Information System (INIS)

    Peng, Chi; Wang, Meie; Chen, Weiping; Chang, Andrew C.

    2015-01-01

    We investigated the polycyclic aromatic hydrocarbons (PAHs) contents in 68 soils samples collected at housing developments that represent different length of development periods across Beijing. Based on the data, we derived a mass balanced mathematical model to simulate the dynamics of PAH accumulations in urban soils as affected by the urban developments. The key parameters were estimated by fitting the modified mass balance model to the data of PAH concentrations vs. building age of the sampling green area. The total PAH concentrations would increase from the baseline of 267 ng g −1 to 3631 ng g −1 during the period of 1978–2048. It showed that the dynamic changes in the rates of accumulations of light and heavy PAH species were related to the shifting of sources of fuels, combustion efficiencies, and amounts of energy consumed during the course of development. - Highlights: • Introduced a mass balance model for soil PAHs accumulation with urbanization. • Reconstructed the historical data of PAH accumulation in soil of Beijing, China. • The soil PAH concentrations would be doubled in the following 40 years. • The composition of PAH emissions were shifting to light PAH species. - Introduced a regression modeling approach to predict the changes of PAH concentrations in urban soil

  5. Evaluating procedural modelling for 3D models of informal settlements in urban design activities

    Directory of Open Access Journals (Sweden)

    Victoria Rautenbach

    2015-11-01

    Full Text Available Three-dimensional (3D modelling and visualisation is one of the fastest growing application fields in geographic information science. 3D city models are being researched extensively for a variety of purposes and in various domains, including urban design, disaster management, education and computer gaming. These models typically depict urban business districts (downtown or suburban residential areas. Despite informal settlements being a prevailing feature of many cities in developing countries, 3D models of informal settlements are virtually non-existent. 3D models of informal settlements could be useful in various ways, e.g. to gather information about the current environment in the informal settlements, to design upgrades, to communicate these and to educate inhabitants about environmental challenges. In this article, we described the development of a 3D model of the Slovo Park informal settlement in the City of Johannesburg Metropolitan Municipality, South Africa. Instead of using time-consuming traditional manual methods, we followed the procedural modelling technique. Visualisation characteristics of 3D models of informal settlements were described and the importance of each characteristic in urban design activities for informal settlement upgrades was assessed. Next, the visualisation characteristics of the Slovo Park model were evaluated. The results of the evaluation showed that the 3D model produced by the procedural modelling technique is suitable for urban design activities in informal settlements. The visualisation characteristics and their assessment are also useful as guidelines for developing 3D models of informal settlements. In future, we plan to empirically test the use of such 3D models in urban design projects in informal settlements.

  6. The backbone of a City Information Model (CIM) : Implementing a spatial data model for urban design

    NARCIS (Netherlands)

    Gil, J.A.; Almeida, J.; Duarte, J.P.

    2011-01-01

    We have been witnessing an increased interest in a more holistic approach to urban design practice and education. In this paper we present a spatial data model for urban design that proposes the combination of urban environment feature classes with design process feature classes. This data model is

  7. A network centrality measure framework for analyzing urban traffic flow: A case study of Wuhan, China

    Science.gov (United States)

    Zhao, Shuangming; Zhao, Pengxiang; Cui, Yunfan

    2017-07-01

    In this paper, we propose an improved network centrality measure framework that takes into account both the topological characteristics and the geometric properties of a road network in order to analyze urban traffic flow in relation to different modes: intersection, road, and community, which correspond to point mode, line mode, and area mode respectively. Degree, betweenness, and PageRank centralities are selected as the analysis measures, and GPS-enabled taxi trajectory data is used to evaluate urban traffic flow. The results show that the mean value of the correlation coefficients between the modified degree, the betweenness, and the PageRank centralities and the traffic flow in all periods are higher than the mean value of the correlation coefficients between the conventional degree, the betweenness, the PageRank centralities and the traffic flow at different modes; this indicates that the modified measurements, for analyzing traffic flow, are superior to conventional centrality measurements. This study helps to shed light into the understanding of urban traffic flow in relation to different modes from the perspective of complex networks.

  8. Studies on urban vehicular ad-hoc networks

    CERN Document Server

    Zhu, Hongzi

    2013-01-01

    With the advancement of wireless technology, vehicular ad hoc networks (VANETs) are emerging as a promising approach to realizing 'smart cities' and addressing many important transportation problems such as road safety, efficiency, and convenience.This brief provides an introduction to the large trace data set collected from thousands of taxis and buses in Shanghai, the largest metropolis in China. It also presents the challenges, design issues, performance modeling and evaluation of a wide spectrum of VANET research topics, ranging from realistic vehicular mobility models and opportunistic ro

  9. Regional disparity of urban passenger transport associated GHG (greenhouse gas) emissions in China: A review

    International Nuclear Information System (INIS)

    Hao, Han; Geng, Yong; Wang, Hewu; Ouyang, Minggao

    2014-01-01

    With China’s urbanization and motorization, greenhouse gas (GHG) emissions from urban passenger transport increased rapidly over recent years. As we estimated, China’s urban passenger transport associated motorized travel, energy consumption and lifecycle GHG emissions reached 2815 billion passenger kilometers (pkm), 77 million tons of oil equivalent (toe) and 335 million ton CO 2 equivalent in 2010, over half of which were located in eastern provinces. Over national level, GHG emissions by private passenger vehicles, business passenger vehicles, taxis, motorcycles, E-bikes, transit buses and urban rails accounted for 57.7%, 13.0%, 7.7%, 8.6%, 1.8%, 10.5% and 0.7% of the total. Significant regional disparity was observed. The province-level per capita GHG emissions ranged from 285 kg/capita in Guizhou to 1273 kg/capita in Beijing, with national average of 486 kg/capita. Depending on province context and local policy orientation, the motorization pathways of China’s several highest motorized provinces are quite diverse. We concluded that motorization rate and transport structure were the substantial factors determining urban passenger transport associated GHG emissions. Considering the great potential of urban passenger transport growth in China, policies guiding the optimization of transport structure should be in place with priority in eastern provinces. - Highlights: • Province-leveled motorized travel, energy consumption and GHG emissions in China were studied. • Significant regional disparities on urban passenger transport were observed. • Region-specific sustainable transport energy policies were discussed

  10. Factores de riesgo de hipertensión arterial: prevalencia y análisis multivariable en los conductores de taxis de la ciudad de Cuenca - Ecuador, año 2014

    OpenAIRE

    Galarza Armijos, Mónica Eulalia; Maldonado Merino, Kathia del Cisne; Suquinagua Pintado, Geovanna Estefanía; Mosquera Vallejo, Lorena Elizabeth

    2016-01-01

    Objetivo: Determinar los factores de riesgo para hipertensión arterial, su prevalencia y análisis multivariable en los conductores de taxis de la ciudad de Cuenca - Ecuador, 2014. Materiales y métodos: Estudio de prevalencia de corte transversal, desarrollado en conductores de taxis residentes en Cuenca - Ecuador. Con un universo de 3 594 taxistas, para la definición del tamaño de la muestra se consideró error de estimativa de 5% y confiabilidad y precisión de la...

  11. A modeling study of the impact of urban trees on ozone

    Science.gov (United States)

    David J. Nowak; Kevin L. Civerolo; S. Trivikrama Rao; Gopal Sistla; Christopher J. Luley; Daniel E. Crane

    2000-01-01

    Modeling the effects of increased urban tree cover on ozone concentrations (July 13-15, 1995) from Washington, DC, to central Massachusetts reveals that urban trees generally reduce ozone concentrations in cities, but tend to increase average ozone concentrations in the overall modeling domain. During the daytime, average ozone reductions in urban areas (1 ppb) were...

  12. Can green roofs reduce urban heat stress in vulnerable urban communities: A coupled atmospheric and social modeling approach

    Science.gov (United States)

    Sharma, A.; Woodruff, S.; Budhathoki, M.; Hamlet, A. F.; Fernando, H. J. S.; Chen, F.

    2017-12-01

    Urban areas provide organized, engineered, sociological and economical infrastructure designed to provide a high quality of life, but the implementation and management of urban infrastructure has been a continued challenge. Increasing urbanization, warming climate, as well as anthropogenic heat emissions that accompany urban development generates "stress". This rapidly increasing `urban stress' affects the sustainability of cities, making populations more vulnerable to extreme hazards, such as heat. Cities are beginning to extensively use green roofs as a potential urban heat mitigation strategy. This study explores the potential of green roofs to reduce summertime temperatures in the most vulnerable neighborhoods of the Chicago metropolitan area by combining social vulnerability indices (a function of exposure, sensitivity and adaptive capacity), and temperatures from mesoscale model. Numerical simulations using urbanized version the Advanced Research Weather Research and Forecasting (WRF) model were performed to measure rooftop temperatures, a representative variable for exposure in this study. The WRF simulations were dynamically coupled with a green roof algorithm as a part of urban parameterization within WRF. Specifically, the study examines roof surface temperature with changing green roof fractions and how would they help reduce exposure to heat stress for vulnerable urban communities. This study shows an example of applied research that can directly benefit urban communities and be used by urban planners to evaluate mitigation strategies.

  13. Spatio-temporal landscape modeling of urban growth patterns in Dhanbad Urban Agglomeration, India using geoinformatics techniques

    Directory of Open Access Journals (Sweden)

    Kanhaiya Lal

    2017-06-01

    Full Text Available The study deals with the quantification of urban sprawl and land transformation of Dhanbad Urban Agglomeration (DUA using geoinformatics and gradient modeling during last four decades (1972–2011. Various multi-temporal satellite images viz., MSS (1972, ETM+ (1999, 2011 and digital elevation model (CARTOSAT I, 2006 were used to analyse the urban expansion, land transformation, growth directions, and spatial segregations within the urban landscape to develop an understanding the nature of built-up growth in DUA. The urban area increased from 10.33 km2 to 46.70 km2 (352.08% along with high rate of population growth (160.07% during 1972–2011 exhibiting population densification in DUA. The study reveals that coal mining based city faced significant land use transformation converting vegetation (−41.33% into built-up land (352.08% exhibiting loss of productive lands for the expansion of impervious surface. The per year urban growth exhibited increasing urban growth from 0.4 km2/year to 1.51 km2/year during 1972–1999 and 1999–2011 periods with overall growth of 332.73%. The built-up growth on varied elevation zones exhibits that the elevation zones 150–200 m is the most preferred (79.01% for urban development with high growth (541.74%. The gradient modeling represents that the percentage of land (built-up gradually increased from 3.48% to 15.74% during 1972–2011. The result exhibited that the major growth took place in south-west direction followed by south direction in haphazard manner during 1971–99 period, whereas predominant built-up development was observed in north, south and south-west direction during 1999–2011 period, majorly within the municipal limits. The study provides an analytical method to evaluate the built-up growth patterns of an urban milieu combining geoinformatics and landscape matrix. The built-up growth in DUA indicates urgent imposition of building bylaws along with zoning (land use, height and density

  14. Integration of LUTI models into sustainable urban mobility plans (SUMPs

    Directory of Open Access Journals (Sweden)

    Nikolaos Gavanas

    2016-06-01

    Full Text Available A literature review indicates that there is an increasing number of Land Use/Transport Interaction (LUTI models being used in policy analysis and support of urban land use, transport and environmental planning. In this context, LUTI models are considered to be useful for the development of scenarios during the preparatory stage of Sustainable Urban Mobility Plans (SUMPs. A SUMP can be defined as a strategic planning framework, proposed by the European Commission, for planning and design of an urban multimodal transport system, which combines multi-disciplinary policy analysis and decision making. The objective of a SUMP is to achieve sustainable urban mobility, i.e. accessibility for all, safety and security, reduction in emissions and energy consumption, efficient and cost-effective transport and an improvement in the urban environment. Based on the overall conceptual and methodological framework of LUTI models (Geurs and van Wee 2004, the scope of the proposed research is to fully integrate a LUTI model into a contemporary transport planning framework and, more specifically, into the SUMP structure. This paper focuses on the configuration of the integration pattern, according to which a LUTI model may evolve and interact with the planning process throughout the eleven elements of the SUMP, as well as the evaluation of the benefits and drawbacks from the implementation of the proposed pattern for the enhancement of SUMP and overall promotion of sustainable urban planning.

  15. Análisis técnico de la vida útil de un lubricante de aceite mineral, para motores de combustión interna a gasolina de los vehículos de servicio de taxis de la ciudad de Cuenca

    OpenAIRE

    Jaramillo Sari, Diego Fernando; Redrován Macas, Luis Fernando; Urgilés Contreras, Diego René

    2011-01-01

    Durante el proyecto se realizó una investigación del parque automotor de taxis de la ciudad de Cuenca, determinando el tipo de aceite usado y su período de cambio. De esta manera, se plantea una encuesta, con la que se pueda determinar el tipo aceite más usado en los vehículos de servicio de taxis. El estudio se realizó en Vehículos de transporte público de servicio de taxi de la ciudad de Cuenca, porque están sometidos a periodos de funcionamiento más extensos, y producen desechos automotric...

  16. Scale effect challenges in urban hydrology highlighted with a distributed hydrological model

    Science.gov (United States)

    Ichiba, Abdellah; Gires, Auguste; Tchiguirinskaia, Ioulia; Schertzer, Daniel; Bompard, Philippe; Ten Veldhuis, Marie-Claire

    2018-01-01

    Hydrological models are extensively used in urban water management, development and evaluation of future scenarios and research activities. There is a growing interest in the development of fully distributed and grid-based models. However, some complex questions related to scale effects are not yet fully understood and still remain open issues in urban hydrology. In this paper we propose a two-step investigation framework to illustrate the extent of scale effects in urban hydrology. First, fractal tools are used to highlight the scale dependence observed within distributed data input into urban hydrological models. Then an intensive multi-scale modelling work is carried out to understand scale effects on hydrological model performance. Investigations are conducted using a fully distributed and physically based model, Multi-Hydro, developed at Ecole des Ponts ParisTech. The model is implemented at 17 spatial resolutions ranging from 100 to 5 m. Results clearly exhibit scale effect challenges in urban hydrology modelling. The applicability of fractal concepts highlights the scale dependence observed within distributed data. Patterns of geophysical data change when the size of the observation pixel changes. The multi-scale modelling investigation confirms scale effects on hydrological model performance. Results are analysed over three ranges of scales identified in the fractal analysis and confirmed through modelling. This work also discusses some remaining issues in urban hydrology modelling related to the availability of high-quality data at high resolutions, and model numerical instabilities as well as the computation time requirements. The main findings of this paper enable a replacement of traditional methods of model calibration by innovative methods of model resolution alteration based on the spatial data variability and scaling of flows in urban hydrology.

  17. A Functional Thinking Approach to the Design of Future Transportation Systems: Taxis as a Proxy for Personal Rapid Transit in South Korea

    DEFF Research Database (Denmark)

    Thompson, Mary Kathryn; Bae, Hyun Hye

    2014-01-01

    For over 50 years, personal rapid transit (PRT) has been viewed as one of the most promising ways to provide sustainable, economical, and convenient transportation while reducing reliance on personal automobiles. However, despite concerted efforts around the world, the promise of PRT has yet...... to be realized. This work demonstrates that different physical means, such as the Korean taxi system, can be used to perform the same highest-level functional requirement, satisfy the same constraints, and provide many of the benefits that are expected of a city-scale personal rapid transit system. Thus, Korean...... taxis can be used as an alternative embodiment of personal rapid transit and can serve as a test bed to support PRT-related design, research, and development. The paper then explores the transportation patterns and characteristics of cities in South Korea and the United States in order to determine...

  18. Assessing the Future Vehicle Fleet Electrification: The Impacts on Regional and Urban Air Quality.

    Science.gov (United States)

    Ke, Wenwei; Zhang, Shaojun; Wu, Ye; Zhao, Bin; Wang, Shuxiao; Hao, Jiming

    2017-01-17

    There have been significant advancements in electric vehicles (EVs) in recent years. However, the different changing patterns in emissions at upstream and on-road stages and complex atmospheric chemistry of pollutants lead to uncertainty in the air quality benefits from fleet electrification. This study considers the Yangtze River Delta (YRD) region in China to investigate whether EVs can improve future air quality. The Community Multiscale Air Quality model enhanced by the two-dimensional volatility basis set module is applied to simulate the temporally, spatially, and chemically resolved changes in PM 2.5 concentrations and the changes of other pollutants from fleet electrification. A probable scenario (Scenario EV1) with 20% of private light-duty passenger vehicles and 80% of commercial passenger vehicles (e.g., taxis and buses) electrified can reduce average PM 2.5 concentrations by 0.4 to 1.1 μg m -3 during four representative months for all urban areas of YRD in 2030. The seasonal distinctions of the air quality impacts with respect to concentration reductions in key aerosol components are also identified. For example, the PM 2.5 reduction in January is mainly attributed to the nitrate reduction, whereas the secondary organic aerosol reduction is another essential contributor in August. EVs can also effectively assist in mitigating NO 2 concentrations, which would gain greater reductions for traffic-dense urban areas (e.g., Shanghai). This paper reveals that the fleet electrification in the YRD region could generally play a positive role in improving regional and urban air quality.

  19. Urban Studies: A Learning Model.

    Science.gov (United States)

    Cooper, Terry L.; Sundeen, Richard

    1979-01-01

    The urban studies learning model described in this article was found to increase students' self-esteem, imbue a more flexible and open perspective, contribute to the capacity for self-direction, produce increases on the feeling reactivity, spontaneity, and acceptance of aggression scales, and expand interpersonal competence. (Author/WI)

  20. Urbanization impacts on mammals across urban-forest edges and a predictive model of edge effects.

    Directory of Open Access Journals (Sweden)

    Nélida R Villaseñor

    Full Text Available With accelerating rates of urbanization worldwide, a better understanding of ecological processes at the wildland-urban interface is critical to conserve biodiversity. We explored the effects of high and low-density housing developments on forest-dwelling mammals. Based on habitat characteristics, we expected a gradual decline in species abundance across forest-urban edges and an increased decline rate in higher contrast edges. We surveyed arboreal mammals in sites of high and low housing density along 600 m transects that spanned urban areas and areas turn on adjacent native forest. We also surveyed forest controls to test whether edge effects extended beyond our edge transects. We fitted models describing richness, total abundance and individual species abundance. Low-density housing developments provided suitable habitat for most arboreal mammals. In contrast, high-density housing developments had lower species richness, total abundance and individual species abundance, but supported the highest abundances of an urban adapter (Trichosurus vulpecula. We did not find the predicted gradual decline in species abundance. Of four species analysed, three exhibited no response to the proximity of urban boundaries, but spilled over into adjacent urban habitat to differing extents. One species (Petaurus australis had an extended negative response to urban boundaries, suggesting that urban development has impacts beyond 300 m into adjacent forest. Our empirical work demonstrates that high-density housing developments have negative effects on both community and species level responses, except for one urban adapter. We developed a new predictive model of edge effects based on our results and the literature. To predict animal responses across edges, our framework integrates for first time: (1 habitat quality/preference, (2 species response with the proximity to the adjacent habitat, and (3 spillover extent/sensitivity to adjacent habitat boundaries. This

  1. Model of urban water management towards water sensitive city: a literature review

    Science.gov (United States)

    Maftuhah, D. I.; Anityasari, M.; Sholihah, M.

    2018-04-01

    Nowadays, many cities are facing with complex issues such as climate change, social, economic, culture, and environmental problems, especially urban water. In other words, the city has to struggle with the challenge to make sure its sustainability in all aspects. This research focuses on how to ensure the city sustainability and resilience on urban water management. Many research were not only conducted in urban water management, but also in sustainability itself. Moreover, water sustainability shifts from urban water management into water sensitive city. This transition needs comprehensive aspects such as social, institutional dynamics, technical innovation, and local contents. Some literatures about model of urban water management and the transition towards water sensitivity had been reviewed in this study. This study proposed discussion about model of urban water management and the transition towards water sensitive city. Research findings suggest that there are many different models developed in urban water management, but they are not comprehensive yet and only few studies discuss about the transition towards water sensitive and resilience city. The drawbacks of previous research can identify and fulfill the gap of this study. Therefore, the paper contributes a general framework for the urban water management modelling studies.

  2. Factores de riesgo de hipertensión arterial: prevalencia y análisis multivariable en los conductores de taxis de la ciudad de Cuenca - Ecuador, año 2014.

    OpenAIRE

    Galarza Armijos, Mónica Eulalia; Maldonado Merino, Kathia del Cisne; Suquinagua Pintado, Geovanna Estefanía; Mosquera Vallejo, Lorena Elizabeth

    2016-01-01

    OBJETIVO: Determinar los factores de riesgo para hipertensión arterial, su prevalencia y análisis multivariable en los conductores de taxis de la ciudad de Cuenca - Ecuador, 2014.MATERIALES Y MÉTODOS: Estudio de prevalencia de corte transversal, desarrollado en conductores de taxis residentes en Cuenca - Ecuador. Con un universo de 3 594 taxistas, para la definición del tamaño de la muestra se consideró error de estimativa de 5% y confiabilidad y precisión de la muestra en 95%, acrecidos 15% ...

  3. Modeling Exposure to Heat Stress with a Simple Urban Model

    Directory of Open Access Journals (Sweden)

    Peter Hoffmann

    2018-01-01

    Full Text Available As a first step in modeling health-related urban well-being (UrbWellth, a mathematical model is constructed that dynamically simulates heat stress exposure of commuters in an idealized city. This is done by coupling the Simple Urban Radiation Model (SURM, which computes the mean radiant temperature ( T m r t , with a newly developed multi-class multi-mode traffic model. Simulation results with parameters chosen for the city of Hamburg for a hot summer day show that commuters are potentially most exposed to heat stress in the early afternoon when T m r t has its maximum. Varying the morphology with respect to street width and building height shows that a more compact city configuration reduces T m r t and therefore the exposure to heat stress. The impact resulting from changes in the city structure on traffic is simulated to determine the time spent outside during the commute. While the time in traffic jams increases for compact cities, the total commuting time decreases due to shorter distances between home and work place. Concerning adaptation measures, it is shown that increases in the albedo of the urban surfaces lead to an increase in daytime heat stress. Dramatic increases in heat stress exposure are found when both, wall and street albedo, are increased.

  4. Assessment of Urban Ecosystem Health Based on Entropy Weight Extension Decision Model in Urban Agglomeration

    Directory of Open Access Journals (Sweden)

    Qian Yang

    2016-08-01

    Full Text Available Urban ecosystem health evaluation can assist in sustainable ecological management at a regional level. This study examined urban agglomeration ecosystem health in the middle reaches of the Yangtze River with entropy weight and extension theories. The model overcomes information omissions and subjectivity problems in the evaluation process of urban ecosystem health. Results showed that human capital and education, economic development level as well as urban infrastructure have a significant effect on the health states of urban agglomerations. The health status of the urban agglomeration’s ecosystem was not optimistic in 2013. The majority of the cities were unhealthy or verging on unhealthy, accounting for 64.52% of the total number of cities in the urban agglomeration. The regional differences of the 31 cities’ ecosystem health are significant. The cause originated from an imbalance in economic development and the policy guidance of city development. It is necessary to speed up the integration process to promote coordinated regional development. The present study will aid us in understanding and advancing the health situation of the urban ecosystem in the middle reaches of the Yangtze River and will provide an efficient urban ecosystem health evaluation method that can be used in other areas.

  5. MODELLING CHALLENGES TO FORECAST URBAN GOODS DEMAND FOR RAIL

    Directory of Open Access Journals (Sweden)

    Antonio COMI

    2015-12-01

    Full Text Available This paper explores the new research challenges for forecasting urban goods demand by rail. In fact, the growing interest to find urban logistics solutions for improving city sustainability and liveability, mainly due to the reduction of urban road accessibility and environmental constraints, has pushed to explore solutions alternative to the road. Multimodal urban logistics, based on the use of railway, seem an interesting alternative solution, but it remained mainly at conceptual level. Few studies have explored the factors, that push actors to find competitive such a system with respect to the road, and modelling framework for forecasting the relative demand. Therefore, paper reviews the current literature, investigates the factors involved in choosing such a mode, and finally, recalls a recent modelling framework and hence proposes some advancements that allow to point out the rail transport alternative.

  6. Urban drainage models simplifying uncertainty analysis for practitioners

    DEFF Research Database (Denmark)

    Vezzaro, Luca; Mikkelsen, Peter Steen; Deletic, Ana

    2013-01-01

    in each measured/observed datapoint; an issue that is commonly overlooked in the uncertainty analysis of urban drainage models. This comparison allows the user to intuitively estimate the optimum number of simulations required to conduct uncertainty analyses. The output of the method includes parameter......There is increasing awareness about uncertainties in the modelling of urban drainage systems and, as such, many new methods for uncertainty analyses have been developed. Despite this, all available methods have limitations which restrict their widespread application among practitioners. Here...

  7. Sensitivity of a complex urban air quality model to input data

    International Nuclear Information System (INIS)

    Seigneur, C.; Tesche, T.W.; Roth, P.M.; Reid, L.E.

    1981-01-01

    In recent years, urban-scale photochemical simulation models have been developed that are of practical value for predicting air quality and analyzing the impacts of alternative emission control strategies. Although the performance of some urban-scale models appears to be acceptable, the demanding data requirements of such models have prompted concern about the costs of data acquistion, which might be high enough to preclude use of photochemical models for many urban areas. To explore this issue, sensitivity studies with the Systems Applications, Inc. (SAI) Airshed Model, a grid-based time-dependent photochemical dispersion model, have been carried out for the Los Angeles basin. Reductions in the amount and quality of meteorological, air quality and emission data, as well as modifications of the model gridded structure, have been analyzed. This paper presents and interprets the results of 22 sensitivity studies. A sensitivity-uncertainty index is defined to rank input data needs for an urban photochemical model. The index takes into account the sensitivity of model predictions to the amount of input data, the costs of data acquistion, and the uncertainties in the air quality model input variables. The results of these sensitivity studies are considered in light of the limitations of specific attributes of the Los Angeles basin and of the modeling conditions (e.g., choice of wind model, length of simulation time). The extent to which the results may be applied to other urban areas also is discussed

  8. Integrated Modelling and Performance Analysis of Green Roof Technologies in Urban Environments

    Science.gov (United States)

    Liu, Xi; Mijic, Ana; Maksimovic, Cedo

    2014-05-01

    As a result of the changing global climate and increase in urbanisation, the behaviour of the urban environment has been significantly altered, causing an increase in both the frequency of extreme weather events, such as flooding and drought, and also the associated costs. Moreover, uncontrolled or inadequately planned urbanisation can exacerbate the damage. The Blue-Green Dream (BGD) project therefore develops a series of components for urban areas that link urban vegetated areas (green infrastructure) with existing urban water (blue) systems, which will enhance the synergy of urban blue and green systems and provide effective, multifunctional BGD solutions to support urban adaptation to future climatic changes. Coupled with new urban water management technologies and engineering, multifunctional benefits can be gained. Some of the technologies associated with BGD solutions include green roofs, swales that might deal with runoff more effectively and urban river restoration that can produce benefits similar to those produced from sustainable urban drainage systems (SUDS). For effective implementation of these technologies, however, appropriate tools and methodologies for designing and modelling BGD solutions are required to be embedded within urban drainage models. Although several software packages are available for modelling urban drainage, the way in which green roofs and other BGD solutions are integrated into these models is not yet fully developed and documented. This study develops a physically based mass and energy balance model to monitor, test and quantitatively evaluate green roof technology for integrated BGD solutions. The assessment of environmental benefits will be limited to three aspects: (1) reduction of the total runoff volume, (2) delay in the initiation of runoff, and (3) reduction of building energy consumption, rather than water quality, visual, social or economic impacts. This physically based model represents water and heat dynamics in a

  9. Analysis of trait-based models in marine ecosystems

    DEFF Research Database (Denmark)

    Heilmann, Irene Louise Torpe

    -temporal pattern formation in a predator–prey system where animals move towards higher fitness. Reaction-diffusion systems have been used extensively to describe spatio-temporal patterns in a variety of systems. However, animals rarely move completely at random, as expressed by diffusion. This has lead to models...... with taxis terms, describing individuals moving in the direction of an attractant. An example is chemotaxis models, where bacteria are attracted to a chemical substance. From an evolutionary perspective, it is expected that animals act as to optimize their fitness. Based on this principle, a predator......–prey system with fitness taxis and diffusion is proposed. Here, fitness taxis refer to animals moving towards higher values of fitness, and the specific growth rates of the populations are used as a measure of the fitness values. To determine the conditions for pattern formation, a linear stability analysis...

  10. Nested High Resolution Modeling of the Impact of Urbanization on Regional Climate in Three Vast Urban Agglomerations in China

    Science.gov (United States)

    Wang, Jun; Feng, Jinming; Yan, Zhongwei; Hu, Yonghong; Jia, Gensuo

    2013-04-01

    In this paper, the Weather Research and Forecasting (WRF) model coupled to the Urban Canopy Model (UCM) is employed to simulate the impact of urbanization on the regional climate over three vast city agglomerations in China. Based on high resolution land use and land cover data, two scenarios are designed to represent the non-urban and current urban land use distributions. By comparing the results of two nested, high resolution numerical experiments, the spatial and temporal changes on surface air temperature, heat stress index, surface energy budget and precipitation due to urbanization are analyzed and quantified. Urban expansion increases the surface air temperature in urban areas by about 1? and this climatic forcing of urbanization on temperature is more pronounced in summer and nighttime than other seasons and daytime. The heat stress intensity, which reflects the combined effects of temperature and humidity, is enhanced by about 0.5 units in urban areas. The regional incoming solar radiation increases after urban expansion, which may be caused by the reduction of cloud fraction. The increased temperature and roughness of the urban surface lead to enhanced convergence. Meanwhile, the planetary boundary layer is deepened and water vapor is mixed more evenly in the lower atmosphere. The deficit of water vapor leads to less convective available potential energy and more convective inhibition energy. Finally, these combined effects may reduce the rainfall amount over urban area mainly in summer and change the regional precipitation pattern to a certain extent.

  11. ANALYTICAL AND SIMULATION PLANNING MODEL OF URBAN PASSENGER TRANSPORT

    Directory of Open Access Journals (Sweden)

    Andrey Borisovich Nikolaev

    2017-09-01

    Full Text Available The article described the structure of the analytical and simulation models to make informed decisions in the planning of urban passenger transport. Designed UML diagram that describes the relationship of classes of the proposed model. A description of the main agents of the model developed in the simulation AnyLogic. Designed user interface integration with GIS map. Also provides simulation results that allow concluding about her health and the possibility of its use in solving planning problems of urban passenger transport.

  12. Influence of Tire Characteristics of Interurban Taxis on Exposure Level to Drivers Whole-Body Vibrations

    Directory of Open Access Journals (Sweden)

    Milad Derakhshanjazari

    2016-03-01

    Full Text Available Introduction: Taxi drivers’ exposure to repeat whole-body vibrations can cause back pain and digestive disorders. Since this type of vibration depends on the car components, this study was carried out to determine the influence of tire characteristics on the amount of whole-body vibrations transmitted to the Peugeot 405 taxi drivers. Methods: In this experimental study, vibration characteristics were measured according to the ISO2631-1 with each of the statuses: tubeless tires fixed and fluid in it (normal air or nitrogen and also the fluid in the tires fixed with tubes or tubeless on asphalt-paved road. Other variables including tire pressure, engine speed, road gradient, number of passengers, springs, and shock absorbers were kept constant. Then the effect of changes was analyzed using an appropriate statistical test. Results: After changing nitrogen to normal air and tubeless tires to tube, the average of RMS in Z-axis, eight-hour equivalent acceleration A(8 and crest factor were reduced (P 0.9 m/s2 to caution zone (0.45-0.9 m/s2 with a value of 0.8 m/s2. Conclusions: The amount of vibration transmitted to the whole body is sensitive to existence of tubes and tires inflation so that we can reduce the amount of whole-body vibration to lower than the upper limit of the health risk by changing the characteristics of the tire

  13. Assessment and cleanup of the Taxi Strip waste storage area at LLNL [Lawrence Livermore National Laboratory

    International Nuclear Information System (INIS)

    Buerer, A.

    1983-01-01

    In September 1982 the Hazards Control Department of the Lawrence Livermore National Laboratory (LLNL) began a final radiological survey of a former low-level radioactive waste storage area called the Taxi Strip so that the area could be released for construction of an office building. Collection of soil samples at the location of a proposed sewer line led to the discovery of an old disposal pit containing soil contaminated with low-level radioactive waste and organic solvents. The Taxi Strip area was excavated leading to the discovery of three additional small pits. The clean-up of Pit No. 1 is considered to be complete for radioactive contamination. The results from the chlorinated solvent analysis of the borehole samples and the limited number of samples analyzed by gas chromatography/mass spectrometry indicate that solvent clean-up at this pit is complete. This is being verified by gas chromatography/mass spectrometry analysis of a few additional soil samples from the bottom sides and ends of the pit. As a precaution, samples are also being analyzed for metals to determine if further excavation is necessary. Clean-up of Pits No. 2 and No. 3 is considered to be complete for radioactive and solvent contamination. Results of analysis for metals will determine if excavation is complete. Excavation of Pit No. 4 which resulted from surface leakage of radioactive contamination from an evaporation tray is complete

  14. Determining of the Parking Manoeuvre and the Taxi Blockage Adjustment Factor for the Saturation Flow Rate at the Outlet Legs of Signalized Intersections: Case Study from Rasht City (Iran)

    Science.gov (United States)

    Behbahani, Hamid; Jahangir Samet, Mehdi; Najafi Moghaddam Gilani, Vahid; Amini, Amir

    2017-10-01

    The presence of taxi stops within the area of signalized intersections at the outlet legs due to unnatural behaviour of the taxis, sudden change of lanes, parking manoeuvres activities and stopping the vehicle to discharge or pick up the passengers have led to reduction of saturation flow rate at the outlet leg of signalized intersections and increased delay as well as affecting the performance of a crossing lane. So far, in term of evaluating effective adjustment factors on saturation flow rate at the inlet legs of the signalized intersections, various studies have been carried out, however; there has not been any studies on effective adjustment factors on saturation flow rate at the inlet legs. Hence, the evaluating of the traffic effects of unique behaviours on the saturation flow rate of the outlet leg is very important. In this research the parking manoeuvre time and taxi blockage time were evaluated and analyzed based on the available lane width as well as determining the effective adjustment factors on the saturation flow rate using recording related data at four signalized intersections in Rasht city. The results show that the average parking manoeuvre time is a function of the lane width and is increased as the lane width is reduced. Also, it is suggested to use the values of 7.37 and 11.31 seconds, respectively for the average parking manoeuvre time and the average blockage time of taxies at the outlet legs of signalized intersections for the traffic designing in Rasht city.

  15. Environmental Modelling of Remediation of Urban Contaminated Areas. Report of the Urban Remediation Working Group of EMRAS Theme 2

    International Nuclear Information System (INIS)

    2012-01-01

    The Urban Remediation Working Group of the International Atomic Energy Agency's EMRAS (Environmental Modelling for RAdiation Safety) programme was concerned with remediation assessment for urban areas contaminated with dispersed radionuclides. Types of events that could result in dispersal or deposition of radionuclides in an urban situation include both intentional and unintentional events, and releases could range from major events involving a nuclear facility to small events such as a transportation accident. The primary objective of the Urban Remediation Working Group was (1) to test and improve the prediction of dose rates and cumulative doses to humans for urban areas contaminated with dispersed radionuclides, including prediction of changes in radionuclide concentrations or dose rates as a function of location and time; (2) to identify the most important pathways for human exposure; and (3) to predict the reduction in radionuclide concentrations, dose rates, or doses expected to result from various countermeasures or remediation efforts. Specific objectives of the Working Group have included (1) the identification of realistic scenarios for a wide variety of situations, (2) comparison and testing of approaches and models for assessing the significance of a given contamination event and for guiding decisions about countermeasures or remediation measures implemented to reduce doses to humans or to clean up the contaminated area, and (3) improving the understanding of processes and situations that affect the spread of contamination to aid in the development of appropriate models and parameter values for use in assessment of these situations. The major activities of the Working Group have included three areas. The first of these was a review of the available modelling approaches and computer models for use in assessing urban contamination and potential countermeasures or remediation activities. The second area of work was a modelling exercise based on data

  16. A Backward-Lagrangian-Stochastic Footprint Model for the Urban Environment

    Science.gov (United States)

    Wang, Chenghao; Wang, Zhi-Hua; Yang, Jiachuan; Li, Qi

    2018-02-01

    Built terrains, with their complexity in morphology, high heterogeneity, and anthropogenic impact, impose substantial challenges in Earth-system modelling. In particular, estimation of the source areas and footprints of atmospheric measurements in cities requires realistic representation of the landscape characteristics and flow physics in urban areas, but has hitherto been heavily reliant on large-eddy simulations. In this study, we developed physical parametrization schemes for estimating urban footprints based on the backward-Lagrangian-stochastic algorithm, with the built environment represented by street canyons. The vertical profile of mean streamwise velocity is parametrized for the urban canopy and boundary layer. Flux footprints estimated by the proposed model show reasonable agreement with analytical predictions over flat surfaces without roughness elements, and with experimental observations over sparse plant canopies. Furthermore, comparisons of canyon flow and turbulence profiles and the subsequent footprints were made between the proposed model and large-eddy simulation data. The results suggest that the parametrized canyon wind and turbulence statistics, based on the simple similarity theory used, need to be further improved to yield more realistic urban footprint modelling.

  17. Understanding Resilient Urban Futures: A Systemic Modelling Approach

    Directory of Open Access Journals (Sweden)

    Ralph Chapman

    2013-07-01

    Full Text Available The resilience of cities in response to natural disasters and long-term climate change has emerged as a focus of academic and policy attention. In particular, how to understand the interconnectedness of urban and natural systems is a key issue. This paper introduces an urban model that can be used to evaluate city resilience outcomes under different policy scenarios. The model is the Wellington Integrated Land Use-Transport-Environment Model (WILUTE. It considers the city (i.e., Wellington as a complex system characterized by interactions between a variety of internal urban processes (social, economic and physical and the natural environment. It is focused on exploring the dynamic relations between human activities (the geographic distribution of housing and employment, infrastructure layout, traffic flows and energy consumption, environmental effects (carbon emissions, influences on local natural and ecological systems and potential natural disasters (e.g., inundation due to sea level rise and storm events faced under different policy scenarios. The model gives insights that are potentially useful for policy to enhance the city’s resilience, by modelling outcomes, such as the potential for reduction in transportation energy use, and changes in the vulnerability of the city’s housing stock and transport system to sea level rise.

  18. Macro-Level Modeling of Urban Transportation Safety: Case-Study of Mashhad (Iran

    Directory of Open Access Journals (Sweden)

    Mohammadi Mehdi

    2017-12-01

    Full Text Available Transportation safety can be aimed at the planning stage in order to adopt safety management and evaluate the long-time policies. The main objective of this research was to make use of crash prediction models in urban transportation planning process. As such, it was attempted to gather data on the results of transportation master plan as well as Mashhad urban crash database. Two modelling method, generalized linear model with negative binomial distribution and geographically weighted regression, were considered as the methods used in this research. Trip variables, including trip by car, trip by bus, trip by bus services and trip by school services, were significant at 95%. The results indicated that both finalized models were competent in predicting urban crashes in Mashhad. Regarding to results urban transportation safety will be improved by changing the modal share for example from private car to bus. The application of the process presented in this study can improve the urban transportation safety management processes and lead to more accurate prediction in terms of crashes across urban traffic areas.

  19. Integrating the simulation of domestic water demand behaviour to an urban water model using agent based modelling

    Science.gov (United States)

    Koutiva, Ifigeneia; Makropoulos, Christos

    2015-04-01

    The urban water system's sustainable evolution requires tools that can analyse and simulate the complete cycle including both physical and cultural environments. One of the main challenges, in this regard, is the design and development of tools that are able to simulate the society's water demand behaviour and the way policy measures affect it. The effects of these policy measures are a function of personal opinions that subsequently lead to the formation of people's attitudes. These attitudes will eventually form behaviours. This work presents the design of an ABM tool for addressing the social dimension of the urban water system. The created tool, called Urban Water Agents' Behaviour (UWAB) model, was implemented, using the NetLogo agent programming language. The main aim of the UWAB model is to capture the effects of policies and environmental pressures to water conservation behaviour of urban households. The model consists of agents representing urban households that are linked to each other creating a social network that influences the water conservation behaviour of its members. Household agents are influenced as well by policies and environmental pressures, such as drought. The UWAB model simulates behaviour resulting in the evolution of water conservation within an urban population. The final outcome of the model is the evolution of the distribution of different conservation levels (no, low, high) to the selected urban population. In addition, UWAB is implemented in combination with an existing urban water management simulation tool, the Urban Water Optioneering Tool (UWOT) in order to create a modelling platform aiming to facilitate an adaptive approach of water resources management. For the purposes of this proposed modelling platform, UWOT is used in a twofold manner: (1) to simulate domestic water demand evolution and (2) to simulate the response of the water system to the domestic water demand evolution. The main advantage of the UWAB - UWOT model

  20. Nested high-resolution modeling of the impact of urbanization on regional climate in three vast urban agglomerations in China

    Science.gov (United States)

    Wang, Jun; Feng, Jinming; Yan, Zhongwei; Hu, Yonghong; Jia, Gensuo

    2012-11-01

    In this paper, the Weather Research and Forecasting Model, coupled to the Urban Canopy Model, is employed to simulate the impact of urbanization on the regional climate over three vast city agglomerations in China. Based on high-resolution land use and land cover data, two scenarios are designed to represent the nonurban and current urban land use distributions. By comparing the results of two nested, high-resolution numerical experiments, the spatial and temporal changes on surface air temperature, heat stress index, surface energy budget, and precipitation due to urbanization are analyzed and quantified. Urban expansion increases the surface air temperature in urban areas by about 1°C, and this climatic forcing of urbanization on temperature is more pronounced in summer and nighttime than other seasons and daytime. The heat stress intensity, which reflects the combined effects of temperature and humidity, is enhanced by about 0.5 units in urban areas. The regional incoming solar radiation increases after urban expansion, which may be caused by the reduction of cloud fraction. The increased temperature and roughness of the urban surface lead to enhanced convergence. Meanwhile, the planetary boundary layer is deepened, and water vapor is mixed more evenly in the lower atmosphere. The deficit of water vapor leads to less convective available potential energy and more convective inhibition energy. Finally, these combined effects may reduce the rainfall amount over urban areas, mainly in summer, and change the regional precipitation pattern to a certain extent.

  1. Three-dimensional modeling of radiative and convective exchanges in the urban atmosphere

    International Nuclear Information System (INIS)

    Qu, Yongfeng

    2011-01-01

    In many micro-meteorological studies, building resolving models usually assume a neutral atmosphere. Nevertheless, urban radiative transfers play an important role because of their influence on the energy budget. In order to take into account atmospheric radiation and the thermal effects of the buildings in simulations of atmospheric flow and pollutant dispersion in urban areas, we have developed a three-dimensional (3D) atmospheric radiative scheme, in the atmospheric module of the Computational Fluid Dynamics model Code-Saturne. The radiative scheme was previously validated with idealized cases, using as a first step, a constant 3D wind field. In this work, the full coupling of the radiative and thermal schemes with the dynamical model is evaluated. The aim of the first part is to validate the full coupling with the measurements of the simple geometry from the 'Mock Urban Setting Test' (MUST) experiment. The second part discusses two different approaches to model the radiative exchanges in urban area with a comparison between Code-Saturne and SOLENE. The third part applies the full coupling scheme to show the contribution of the radiative transfer model on the airflow pattern in low wind speed conditions in a 3D urban canopy. In the last part we use the radiative-dynamics coupling to simulate a real urban environment and validate the modeling approach with field measurements from the 'Canopy and Aerosol Particles Interactions in Toulouse Urban Layer' (CAPITOUL). (author) [fr

  2. Integration of cabs and hired cars in urban transportation systems

    Energy Technology Data Exchange (ETDEWEB)

    Bernauer,

    1984-01-01

    Integrating taxis and limousine services into the public transit system has become a major goal in designing new forms of public transportation. Expanding the spectrum of possible use for these vehicles - for both scheduled and on-demand service - requires, first of all, a qualitative and quantitative analysis of the current state of affairs in this area. Administrative, organizational, technical, and legal issues as well as the respective traffic patterns had to be investigated. This investigation was to find out if, and in what ways, taxis and limousine services could actually be incorporated into the public transit system. In addition, the results were interpreted against the background of experiments and tentative models for regular, scheduled and supplementary public transit. As a result, we developed a generalized concept for integrating the two systems and proposed possible forms of service, organization, and financial calculation. Included were legal issues and comments on contractual relations between the partners.

  3. Characteristics and diurnal variations of NMHCs at urban, suburban, and rural sites in the Pearl River Delta and a remote site in South China

    Science.gov (United States)

    Tang, J. H.; Chan, L. Y.; Chan, C. Y.; Li, Y. S.; Chang, C. C.; Liu, S. C.; Wu, D.; Li, Y. D.

    The Pearl River Delta (PRD) is one of the most industrialized and urbanized regions in China. With rapid growth of the economy, it is suffering from deteriorating air quality. Non-methane hydrocarbons (NMHCs) were investigated at urban and suburban sites in Guangzhou (GZ), a rural site in PRD and a clean remote site in South China, in April 2005. Additional roadside samples in GZ and Qingxi (QX, a small industrial town in PRD), ambient air samples at the rooftop of a printing factory in QX and exhaust samples from liquefied petroleum gas (LPG)—fueled taxis in GZ were collected to help identify the source signatures of NMHCs. A large fraction of propane (47%) was found in exhaust samples from LPG-fueled taxis in GZ and extremely high levels of toluene (2.0-3.1 ppmv) were found at the rooftop of the printing factory in QX. Vehicular and industrial emissions were the main sources of NMHCs. The effect of vehicular emission on the ambient air varied among the three PRD sites. The impact of industrial emissions was widespread and they contributed greatly to the high levels of aromatic hydrocarbons, especially toluene, at the three PRD sites investigated. Leakage from vehicles fueled by LPG contributed mainly to the high levels of propane and n-butane at the urban GZ site. Ethane and ethyne from long-range transport and isoprene from local biogenic emission were the main contributors to the total hydrocarbons at the remote site. Diurnal variations of NMHCs showed that the contribution from vehicular emissions varied with traffic conditions and were more influenced by fresh emissions at the urban site and by aged air at the suburban and rural sites. Isoprene from biogenic emission contributed largely to the ozone formation potential (OFP) at the remote site. Ethene, toluene and m/ p-xylene were the main contributors to the OFP at the three PRD sites.

  4. High resolution modelling of extreme precipitation events in urban areas

    Science.gov (United States)

    Siemerink, Martijn; Volp, Nicolette; Schuurmans, Wytze; Deckers, Dave

    2015-04-01

    The present day society needs to adjust to the effects of climate change. More extreme weather conditions are expected, which can lead to longer periods of drought, but also to more extreme precipitation events. Urban water systems are not designed for such extreme events. Most sewer systems are not able to drain the excessive storm water, causing urban flooding. This leads to high economic damage. In order to take appropriate measures against extreme urban storms, detailed knowledge about the behaviour of the urban water system above and below the streets is required. To investigate the behaviour of urban water systems during extreme precipitation events new assessment tools are necessary. These tools should provide a detailed and integral description of the flow in the full domain of overland runoff, sewer flow, surface water flow and groundwater flow. We developed a new assessment tool, called 3Di, which provides detailed insight in the urban water system. This tool is based on a new numerical methodology that can accurately deal with the interaction between overland runoff, sewer flow and surface water flow. A one-dimensional model for the sewer system and open channel flow is fully coupled to a two-dimensional depth-averaged model that simulates the overland flow. The tool uses a subgrid-based approach in order to take high resolution information of the sewer system and of the terrain into account [1, 2]. The combination of using the high resolution information and the subgrid based approach results in an accurate and efficient modelling tool. It is now possible to simulate entire urban water systems using extreme high resolution (0.5m x 0.5m) terrain data in combination with a detailed sewer and surface water network representation. The new tool has been tested in several Dutch cities, such as Rotterdam, Amsterdam and The Hague. We will present the results of an extreme precipitation event in the city of Schiedam (The Netherlands). This city deals with

  5. Modeling of the service taxi

    OpenAIRE

    R. M. Bezborodnikova

    2016-01-01

    Modeling and optimization business processes are ongoing challenges of modernity. Based on the study of business processes to anticipate and avoid many problems in the work of companies linked primarily with an increased level of costs, the low quality of the performed works and manufactured products, excessive run time functions. Application of simulation tool for business processes allows at the stage of planning to assess various indicators of the effectiveness of processes to identify the...

  6. Real-time modeling of complex atmospheric releases in urban areas

    International Nuclear Information System (INIS)

    Baskett, R.L.; Ellis, J.S.; Sullivan, T.J.

    1994-08-01

    If a nuclear installation in or near an urban area has a venting, fire, or explosion, airborne radioactivity becomes the major concern. Dispersion models are the immediate tool for estimating the dose and contamination. Responses in urban areas depend on knowledge of the amount of the release, representative meteorological data, and the ability of the dispersion model to simulate the complex flows as modified by terrain or local wind conditions. A centralized dispersion modeling system can produce realistic assessments of radiological accidents anywhere in a country within several minutes if it is computer-automated. The system requires source-term, terrain, mapping and dose-factor databases, real-time meteorological data acquisition, three-dimensional atmospheric transport and dispersion models, and experienced staff. Experience with past responses in urban areas by the Atmospheric Release Advisory Capability (ARAC) program at Lawrence Livermore National Laboratory illustrate the challenges for three-dimensional dispersion models

  7. Real-time modelling of complex atmospheric releases in urban areas

    International Nuclear Information System (INIS)

    Baskett, R.L.; Ellis, J.S.; Sullivan, T.J.

    2000-01-01

    If a nuclear installation in or near an urban area has a venting, fire, or explosion, airborne radioactivity becomes the major concern. Dispersion models are the immediate tool for estimating the dose and contamination. Responses in urban areas depend on knowledge of the amount of the release, representative meteorological data, and the ability of the dispersion model to simulate the complex flows as modified by terrain or local wind conditions. A centralised dispersion modelling system can produce realistic assessments of radiological accidents anywhere in a country within several minutes if it is computer-automated. The system requires source-term, terrain, mapping and dose-factor databases, real-time meteorological data acquisition, three-dimensional atmospheric transport and dispersion models, and experienced staff. Experience with past responses in urban areas by the Atmospheric Release Advisory Capability (ARAC) program at Lawrence Livermore National Laboratory illustrate the challenges for three-dimensional dispersion models. (author)

  8. Modelling Urban Experiences

    DEFF Research Database (Denmark)

    Jantzen, Christian; Vetner, Mikael

    2008-01-01

    How can urban designers develop an emotionally satisfying environment not only for today's users but also for coming generations? Which devices can they use to elicit interesting and relevant urban experiences? This paper attempts to answer these questions by analyzing the design of Zuidas, a new...

  9. Procedural modeling of urban layout: population, land use, and road network

    NARCIS (Netherlands)

    Lyu, X.; Han, Q.; de Vries, B.

    2017-01-01

    This paper introduces an urban simulation system generating urban layouts with population, road network and land use layers. The desired urban spatial structure is obtained by generating a population map based on population density models. The road network is generated at two spatial levels

  10. Modelling regional climate change and urban planning scenarios and their impacts on the urban environment in two cities with WRF-ACASA

    Science.gov (United States)

    Falk, M.; Pyles, R. D.; Marras, S.; Spano, D.; Paw U, K. T.

    2011-12-01

    The number of urban metabolism studies has increased in recent years, due to the important impact that energy, water and carbon exchange over urban areas have on climate change. Urban modeling is therefore crucial in the future design and management of cities. This study presents the ACASA model coupled to the Weather Research and Forecasting (WRF-ARW) mesoscale model to simulate urban fluxes at a horizontal resolution of 200 meters for urban areas of roughly 100 km^2. As part of the European Project "BRIDGE", these regional simulations were used in combination with remotely sensed data to provide constraints on the land surface types and the exchange of carbon and energy fluxes from urban centers. Surface-atmosphere exchanges of mass and energy were simulated using the Advanced Canopy Atmosphere Soil Algorithm (ACASA). ACASA is a multi-layer high-order closure model, recently modified to work over natural, agricultural as well as urban environments. In particular, improvements were made to account for the anthropogenic contribution to heat and carbon production. For two cities four climate change and four urban planning scenarios were simulated: The climate change scenarios include a base scenario (Sc0: 2008 Commit in IPCC), a medium emission scenario (Sc1: IPCC A2), a worst case emission scenario (Sce2: IPCC A1F1) and finally a best case emission scenario (Sce3: IPCC B1). The urban planning scenarios include different development scenarios such as smart growth. The two cities are a high latitude city, Helsinki (Finland) and an historic city, Florence (Italy). Helsinki is characterized by recent, rapid urbanization that requires a substantial amount of energy for heating, while Florence is representative of cities in lower latitudes, with substantial cultural heritage and a comparatively constant architectural footprint over time. In general, simulated fluxes matched the point observations well and showed consistent improvement in the energy partitioning over

  11. An Integrated Modelling Framework to Assess Flood Risk under Urban Development and Changing Climate

    DEFF Research Database (Denmark)

    that combines a model for the socio-economic development of cities (DANCE4WATER) with an urban flood model. The urban flood model is a 1D-2D spatially distributed hydrologic and hydraulic model that, for a given urban layout, simulates flow in the sewer system and the surface flow in the catchment (MIKE FLOOD......). The socio-economic model computes urban layouts that are transferred to the hydraulic model in the form of changes of impervious area and potential flow paths on the surface. Estimates of flood prone areas, as well as the expected annual damage due to flooding, are returned to the socio-economic model...... as an input for further refinement of the scenarios for the urban development. Our results in an Australian case study suggest that urban development is a major driver for flood risk and vice versa that flood risk can be significantly reduced if it is accounted for in the development of the cities...

  12. A german vision of urban models. The case of Querétaro

    Directory of Open Access Journals (Sweden)

    Christof Göbel

    2015-08-01

    Full Text Available Due to their complexity, the organization, function and morphology of cities has been historically reduced to graphic abstractions or urban “models” with the intention to identify types of cities according to the cultural space in question. However, by their nature, cities are under constant change and transformation, which gives rise to many questions about the validity and the relevance of these urban models: Are these models still a way to understand the logic and structure of cities? Can we understand urban morphology through these schemes? Are there urban models to understand a “medium sized” city? Departing from these questions, the aim of this article is to explore whether current urban models continue corresponding with the morphology and structure of a city, and with the changes that occur in them in a ten-year period, as it is the case of the city of Querétaro.

  13. Parameterizing Urban Canopy Layer transport in an Lagrangian Particle Dispersion Model

    Science.gov (United States)

    Stöckl, Stefan; Rotach, Mathias W.

    2016-04-01

    The percentage of people living in urban areas is rising worldwide, crossed 50% in 2007 and is even higher in developed countries. High population density and numerous sources of air pollution in close proximity can lead to health issues. Therefore it is important to understand the nature of urban pollutant dispersion. In the last decades this field has experienced considerable progress, however the influence of large roughness elements is complex and has as of yet not been completely described. Hence, this work studied urban particle dispersion close to source and ground. It used an existing, steady state, three-dimensional Lagrangian particle dispersion model, which includes Roughness Sublayer parameterizations of turbulence and flow. The model is valid for convective and neutral to stable conditions and uses the kernel method for concentration calculation. As most Lagrangian models, its lower boundary is the zero-plane displacement, which means that roughly the lower two-thirds of the mean building height are not included in the model. This missing layer roughly coincides with the Urban Canopy Layer. An earlier work "traps" particles hitting the lower model boundary for a recirculation period, which is calculated under the assumption of a vortex in skimming flow, before "releasing" them again. The authors hypothesize that improving the lower boundary condition by including Urban Canopy Layer transport could improve model predictions. This was tested herein by not only trapping the particles, but also advecting them with a mean, parameterized flow in the Urban Canopy Layer. Now the model calculates the trapping period based on either recirculation due to vortex motion in skimming flow regimes or vertical velocity if no vortex forms, depending on incidence angle of the wind on a randomly chosen street canyon. The influence of this modification, as well as the model's sensitivity to parameterization constants, was investigated. To reach this goal, the model was

  14. Uncertainty Assessment in Urban Storm Water Drainage Modelling

    DEFF Research Database (Denmark)

    Thorndahl, Søren

    The object of this paper is to make an overall description of the author's PhD study, concerning uncertainties in numerical urban storm water drainage models. Initially an uncertainty localization and assessment of model inputs and parameters as well as uncertainties caused by different model...

  15. Comparison Of Taxis And Logical Semantic Systems In Indonesian And Malaysian Newspapers About Airasia Qz8501 Accident

    OpenAIRE

    Syahputra, Yudha

    2016-01-01

    This study seeks to describe the comparative portion of taxis and logical semantic systems between Malaysian and Indonesian newspapers’ articles about AirAsia QZ8501 accident. The data are clause complexes in Indonesia naval captain says may have located missing plane tail’s section’s New Straits Times (Text A) and AirAsia tail section located, blackbox still missing’s The Jakarta Post (Text B) articles. This study uses qualitative-descriptive method. As the result, both par...

  16. An Investigation on the Sensitivity of the Parameters of Urban Flood Model

    Science.gov (United States)

    M, A. B.; Lohani, B.; Jain, A.

    2015-12-01

    Global climatic change has triggered weather patterns which lead to heavy and sudden rainfall in different parts of world. The impact of heavy rainfall is severe especially on urban areas in the form of urban flooding. In order to understand the effect of heavy rainfall induced flooding, it is necessary to model the entire flooding scenario more accurately, which is now becoming possible with the availability of high resolution airborne LiDAR data and other real time observations. However, there is not much understanding on the optimal use of these data and on the effect of other parameters on the performance of the flood model. This study aims at developing understanding on these issues. In view of the above discussion, the aim of this study is to (i) understand that how the use of high resolution LiDAR data improves the performance of urban flood model, and (ii) understand the sensitivity of various hydrological parameters on urban flood modelling. In this study, modelling of flooding in urban areas due to heavy rainfall is carried out considering Indian Institute of Technology (IIT) Kanpur, India as the study site. The existing model MIKE FLOOD, which is accepted by Federal Emergency Management Agency (FEMA), is used along with the high resolution airborne LiDAR data. Once the model is setup it is made to run by changing the parameters such as resolution of Digital Surface Model (DSM), manning's roughness, initial losses, catchment description, concentration time, runoff reduction factor. In order to realize this, the results obtained from the model are compared with the field observations. The parametric study carried out in this work demonstrates that the selection of catchment description plays a very important role in urban flood modelling. Results also show the significant impact of resolution of DSM, initial losses and concentration time on urban flood model. This study will help in understanding the effect of various parameters that should be part of a

  17. Enhancing photogrammetric 3d city models with procedural modeling techniques for urban planning support

    International Nuclear Information System (INIS)

    Schubiger-Banz, S; Arisona, S M; Zhong, C

    2014-01-01

    This paper presents a workflow to increase the level of detail of reality-based 3D urban models. It combines the established workflows from photogrammetry and procedural modeling in order to exploit distinct advantages of both approaches. The combination has advantages over purely automatic acquisition in terms of visual quality, accuracy and model semantics. Compared to manual modeling, procedural techniques can be much more time effective while maintaining the qualitative properties of the modeled environment. In addition, our method includes processes for procedurally adding additional features such as road and rail networks. The resulting models meet the increasing needs in urban environments for planning, inventory, and analysis

  18. Urban Transportation: Issue and Solution

    Directory of Open Access Journals (Sweden)

    Haryati Shafii

    2011-10-01

    Full Text Available Generally, quality of life of urban population is heavily dependent on social facilities provided within the environment. One of the most important facilities is transportations. Study on transportation mode in an urban area is especially very important because for almost every individual living in a large and densely populated area, mobility is one of the most crucial issues in everyday life. Enhance mobility, faster journey to work and less pollution from petrol-propelled vehicles can increase the quality of life, which in turn lead to a sustainable urban living. The study present transportation mode usage issues faced by community related to quality of life in an urban area. This study identifies several issues of transportation mode in urban areas and its impact on the quality of life. The study areas are Putrajaya, Kuala Lumpur and Bandar Kajang, Selangor. The methodology used in this research is secondary and primary data. The questionnaires for the survey were distributed from May 2008 to Jun 2008. These researches were conducted on 144 respondents for to evaluate their perception of transportation mode correlated to the quality of life. The collected data were then analyzed using “Statistical Packages for the Social Science” (SPSS. The respondents comprise of 61 males and 84 females from the age group of 18 to 57 years. This study identifies the percentage of public transportation mode usage in urban area, such as buses (16.7%, train (ERL, monorail and commuter-6.4%; which is very low compared to owning personal car (45.8% and motorcycle (25.4%.The result shows owning personal car is the highest (45.8% in three study areas and monorail and taxi are the lowest (1.4%. The Chi Square Test shows that among the mode transportation with traffic jam is quite difference in Kuala Lumpur, Putrajaya and Kajang. Analysis of the Chi Square Test shows the result is 0.000 (two sides to respondent answering “yes” and analysis of Spearman

  19. MODEL OF BRAZILIAN URBANIZATION: GENERAL NOTES

    Directory of Open Access Journals (Sweden)

    Leandro da Silva Guimarães

    2016-07-01

    Full Text Available The full text format seeks to analyze the social inequality in Brazil through the spatial process of that inequality in this sense it analyzes, scratching the edges of what is known of the Brazilian urbanization model and how this same model produced gentrification cities and exclusive. So search the text discuss the country’s urban exclusion through consolidation of what is conventionally called peripheral areas, or more generally, of peripheries. The text on screen is the result of research carried out at the Federal Fluminense University in Masters level. In this study, we tried to understand the genesis of an urban housing development located in São Gonçalo, Rio de Janeiro called Jardim Catarina. Understand what the problem space partner who originated it. In this sense, his analysis becomes consubstantial to understand the social and spatial inequalities in Brazil, as well as the role of the state as planning manager socio-spatial planning and principal agent in the solution of such problems. It is expected that with the realization of a study of greater amounts, from which this article is just a micro work can contribute subsidies that contribute to the arrangement and crystallization of public policies that give account of social inequalities and serve to leverage a country more fair and equitable cities.

  20. Urban Saturated Power Load Analysis Based on a Novel Combined Forecasting Model

    Directory of Open Access Journals (Sweden)

    Huiru Zhao

    2015-03-01

    Full Text Available Analysis of urban saturated power loads is helpful to coordinate urban power grid construction and economic social development. There are two different kinds of forecasting models: the logistic curve model focuses on the growth law of the data itself, while the multi-dimensional forecasting model considers several influencing factors as the input variables. To improve forecasting performance, a novel combined forecasting model for saturated power load analysis was proposed in this paper, which combined the above two models. Meanwhile, the weights of these two models in the combined forecasting model were optimized by employing a fruit fly optimization algorithm. Using Hubei Province as the example, the effectiveness of the proposed combined forecasting model was verified, demonstrating a higher forecasting accuracy. The analysis result shows that the power load of Hubei Province will reach saturation in 2039, and the annual maximum power load will reach about 78,630 MW. The results obtained from this proposed hybrid urban saturated power load analysis model can serve as a reference for sustainable development for urban power grids, regional economies, and society at large.

  1. Sociodemographic factors associated with aggressive driving behaviors of 3-wheeler taxi drivers in Sri Lanka.

    Science.gov (United States)

    Akalanka, Ediriweera Chintana; Fujiwara, Takeo; Desapriya, Ediriweera; Peiris, Dinithi C; Scime, Giulia

    2012-01-01

    Little is known about the nature and scope of aggressive driving in developing countries. The objective of this study is to specifically examine the sociodemographic factors associated with aggressive driving behavior among 3-wheeler taxi drivers in Sri Lanka. Convenience samples of 3-wheeler taxi drivers from Rathnapura, Ahaliyagoda, Sri Lanka were surveyed from June to August 2006. Analyses included bivariate and multivariate logistic regression. Drivers with less than high school education were 3.5 times more likely to drive aggressively (odds ratio [OR] = 3.46; 95% confidence interval [CI] = 1.08, 11.1). Single drivers were 9 times more likely to run red lights (OR = 8.74; 95% CI = 2.18, 35.0), and being single was a major risk factor for drunk driving (OR = 4.80; 95% CI = 1.23, 18.7). Furthermore, high school completers were 4 times more likely to bribe a policeman (OR = 4.27; 95% CI = 1.23, 14.9) when caught violating the road rules. Aggressive driving and risk-taking behavior are amenable to policy initiatives, and preventive programs targeted at key groups could be used to improve road safety in Sri Lanka. This study demonstrates that aggressive driving behavior is associated with sociodemographic factors, including the level of education, marital status, and other socioeconomic factors. Hence, economic factors should be addressed to find solutions to traffic-related issues. It will be the government's and policy makers' responsibility to try and understand the economic factors behind risky road behavior and bribe-taking behavior prior to legislating or enforcing new laws.

  2. A QUADTREE ORGANIZATION CONSTRUCTION AND SCHEDULING METHOD FOR URBAN 3D MODEL BASED ON WEIGHT

    OpenAIRE

    C. Yao; G. Peng; Y. Song; M. Duan

    2017-01-01

    The increasement of Urban 3D model precision and data quantity puts forward higher requirements for real-time rendering of digital city model. Improving the organization, management and scheduling of 3D model data in 3D digital city can improve the rendering effect and efficiency. This paper takes the complexity of urban models into account, proposes a Quadtree construction and scheduling rendering method for Urban 3D model based on weight. Divide Urban 3D model into different rendering weigh...

  3. Future Climate Prediction of Urban Atmosphere in A Tropical Megacity: Utilization of RCP/SSP Scenarios with an Urban Growth Model

    Science.gov (United States)

    Darmanto, N. S.; Varquez, A. C. G.; Kanda, M.; Takakuwa, S.

    2016-12-01

    Economic development in Southeast Asia megacities leads to rapid transformation into more complicated urban configurations. These configurations, including building geometry, enhance aerodynamic drag thus reducing near-surface wind speeds. Roughness parameters representing building geometry, along with anthropogenic heat emissions, contribute to the formation of urban heat islands (UHI). All these have been reproduced successfully in the Weather Research and Forecasting (WRF) Model coupled with an improved single-layer urban canopy model incorporating a realistic distribution of urban parameters and anthropogenic heat emission in the Jakarta Greater Area. We apply this technology to climate change studies by introducing future urbanization defined by urban sprawl, vertical rise in buildings, and increase anthropogenic heat emission (AHE) due to population changes, into futuristic climate modelling. To simulate 2050s future climate, pseudo-global warming method was used which relied on current and ensembles of 5 CMIP5 GCMs for 2 representative concentration pathways (RCP), 2.6 and 8.5. To determine future urbanization level, 2050 population growth and energy consumption were estimated from shared socioeconomic pathways (SSP). This allows the estimation of future urban sprawl, building geometry, and AHE using the SLEUTH urban growth model and spatial growth assumptions. Two cases representing combinations of RCP and SSP were simulated in WRF: RCP2.6-SSP1 and RCP8.5-SSP3. Each case corresponds to best and worst-case scenarios of implementing adaptation and mitigation strategies, respectively. It was found that 2-m temperature of Jakarta will increase by 0.62°C (RCP2.6) and 1.44°C (RCP8.5) solely from background climate change; almost on the same magnitude as the background temperature increase of RCP2.6 (0.5°C) and RCP8.5 (1.2°C). Compared with previous studies, the result indicates that the effect of climate change on UHI in tropical cities may be lesser than

  4. A spatially distributed model for assessment of the effects of changing land use and climate on urban stream quality: Development of a Spatially Distributed Urban Water Quality Model

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Ning [Department of Civil and Environmental Engineering, University of Washington, Seattle WA USA; Pacific Northwest National Laboratory, Richland WA USA; Yearsley, John [Department of Civil and Environmental Engineering, University of Washington, Seattle WA USA; Baptiste, Marisa [Department of Civil and Environmental Engineering, University of Washington, Seattle WA USA; Cao, Qian [Department of Geography, University of California Los Angeles, Los Angeles CA USA; Lettenmaier, Dennis P. [Department of Geography, University of California Los Angeles, Los Angeles CA USA; Nijssen, Bart [Department of Civil and Environmental Engineering, University of Washington, Seattle WA USA

    2016-08-22

    While the effects of land use change in urban areas have been widely examined, the combined effects of climate and land use change on the quality of urban and urbanizing streams have received much less attention. We describe a modeling framework that is applicable to the evaluation of potential changes in urban water quality and associated hydrologic changes in response to ongoing climate and landscape alteration. The grid-based spatially distributed model, DHSVM-WQ, is an outgrowth of the Distributed Hydrology-Soil-Vegetation Model (DHSVM) that incorporates modules for assessing hydrology and water quality in urbanized watersheds at a high spatial and temporal resolution. DHSVM-WQ simulates surface runoff quality and in-stream processes that control the transport of nonpoint-source (NPS) pollutants into urban streams. We configure DHSVM-WQ for three partially urbanized catchments in the Puget Sound region to evaluate the water quality responses to current conditions and projected changes in climate and/or land use over the next century. Here we focus on total suspended solids (TSS) and total phosphorus (TP) from nonpoint sources (runoff), as well as stream temperature. The projection of future land use is characterized by a combination of densification in existing urban or partially urban areas, and expansion of the urban footprint. The climate change scenarios consist of individual and concurrent changes in temperature and precipitation. Future precipitation is projected to increase in winter and decrease in summer, while future temperature is projected to increase throughout the year. Our results show that urbanization has a much greater effect than climate change on both the magnitude and seasonal variability of streamflow, TSS and TP loads largely due to substantially increased streamflow, and particularly winter flow peaks. Water temperature is more sensitive to climate warming scenarios than to urbanization and precipitation changes. Future urbanization and

  5. Energy Taxis Drives Campylobacter jejuni toward the Most Favorable Conditions for Growth

    DEFF Research Database (Denmark)

    Vegge, C.S.; Brondsted, L.; Li, Yiping

    2009-01-01

    Campylobacter jejuni is a serious food-borne bacterial pathogen in the developed world. Poultry is a major reservoir, and C. jejuni appears highly adapted to the gastrointestinal tract of birds. Several factors are important for chicken colonization and virulence, including a taxis mechanism...... identified as new attractants of C. jejuni, and we observed that chemical substances promoting tactic attraction are all known to support the growth of this organism. The attractants could be categorized as carbon sources and electron donors and acceptors, and we furthermore observed a correlation between...... an attractant's potency and its efficiency as an energy source. The tactic attraction was inhibited by the respiratory inhibitors HQNO (2-n-heptyl-4-hydroxyquinoline N-oxide) and sodium azide, which significantly reduce energy production by oxidative phosphorylation. These findings strongly indicate that energy...

  6. Object Tracking with LiDAR: Monitoring Taxiing and Landing Aircraft

    Directory of Open Access Journals (Sweden)

    Zoltan Koppanyi

    2018-02-01

    Full Text Available Mobile light detection and ranging (LiDAR sensors used in car navigation and robotics, such as the Velodyne’s VLP-16 and HDL-32E, allow for sensing the surroundings of the platform with high temporal resolution to detect obstacles, tracking objects and support path planning. This study investigates the feasibility of using LiDAR sensors for tracking taxiing or landing aircraft close to the ground to improve airport safety. A prototype system was developed and installed at an airfield to capture point clouds to monitor aircraft operations. One of the challenges of accurate object tracking using the Velodyne sensors is the relatively small vertical field of view (30°, 41.3° and angular resolution (1.33°, 2°, resulting in a small number of points of the tracked object. The point density decreases with the object–sensor distance, and is already sparse at a moderate range of 30–40 m. The paper introduces our model-based tracking algorithms, including volume minimization and cube trajectories, to address the optimal estimation of object motion and tracking based on sparse point clouds. Using a network of sensors, multiple tests were conducted at an airport to assess the performance of the demonstration system and the algorithms developed. The investigation was focused on monitoring small aircraft moving on runways and taxiways, and the results indicate less than 0.7 m/s and 17 cm velocity and positioning accuracy achieved, respectively. Overall, based on our findings, this technology is promising not only for aircraft monitoring but for airport applications.

  7. A dispersion modelling system for urban air pollution

    Energy Technology Data Exchange (ETDEWEB)

    Karppinen, A.; Kukkonen, J.; Nordlund, G.; Rantakrans, E.; Valkama, I.

    1998-10-01

    An Urban Dispersion Modelling system UDM-FMI, developed at the Finnish Meteorological Institute is described in the report. The modelling system includes a multiple source Gaussian plume model and a meteorological pre-processing model. The dispersion model is an integrated urban scale model, taking into account of all source categories (point, line, area and volume sources). It includes a treatment of chemical transformation (for NO{sub 2}) wet and dry deposition (for SO{sub 2}) plume rise, downwash phenomena and dispersion of inert particles. The model allows also for the influence of a finite mixing height. The model structure is mainly based on the state-of-the-art methodology. The system also computes statistical parameters from the time series, which can be compared to air quality guidelines. The relevant meteorological parameters for the dispersion model are evaluated using data produced by a meteorological pre-processor. The model is based mainly on the energy budget method. Results of national investigations have been used for evaluating climate-dependent parameters. The model utilises the synoptic meteorological observations, radiation records and aerological sounding observations. The model results include the hourly time series of the relevant atmospheric turbulence 51 refs.

  8. Estudio de la vida útil de los vehículos desde la perspectiva de la gestión de mantenimiento del transporte público modalidad taxis de la ciudad de Cuenca

    OpenAIRE

    Espinoza Sibri, Víctor Geovanny; Ortega Lema, Edwin Paúl; Sancho Carchipulla, Marco Vinicio

    2012-01-01

    La (ANT) Agencia Nacional de Transporte, Transito y Seguridad Vial ha establecido que la vida útil de los vehículos de servicio público modalidad taxis es de 10 años, por lo tanto en el desarrollo de la presente tesis se ha comprobado desde la perspectiva de la gestión de mantenimiento, si se cumple lo determinado por la entidad. Actualmente existe un total de 3555 unidades de taxis vigentes de distinta marca, modelo y año de fabricación que prestan su servicio de transporte a todos los ha...

  9. Urban farming model in South Jakarta

    Science.gov (United States)

    Indrawati, E.

    2018-01-01

    The development of infrastructure rapidly, large of population and large of urbanization. Meanwhile, agricultural land is decreasing and agricultural production continues to decline. The productive crops is needed for consumption and it is also to improve the environment from oxygen provisioning, antidote to air pollution and to improve soil conditions. The use of yard land for horticultural crops (vegetables, fruits and ornamental plants), spices, medicines, herbs etc. can benefit for the owners of the yard particularly and the general public. The purpose of this research is to identify the model of home yard utilization, mosque yard, office, school, urban park and main road and sub main road, which can improve environmental quality in Pesanggrahan district. The method of analysis used descriptive analysis method by observation. Then analyzed the percentage of the use of yard with productive crops as urban farming. The results showed that the most productive crops were planted in Kelurahan Pesanggrahan 67% which compared with in Kelurahan Ulujami 47%, and in Kelurahan Petukangan Utara 27%. The most types of productive crops were grown as fruit trees and vegetable crops.

  10. PARATI - a dynamic model for radiological assessments in urban areas. Pt. 1. Modelling of urban areas, their contamination and radiation fields

    International Nuclear Information System (INIS)

    Rochedo, E.R.R.; Conti, L.F.C.; Paretzke, H.G.

    1996-01-01

    The structure and mathematical model of PARATI, a detailed computer programme developed for the assessment of the radiological consequences of an accidental contamination of urban areas, is described with respect to the scenarios used for the estimation of exposure fields in a village or town, the models for the initial and secondary contamination with the radionuclide 137 Cs, the concepts for calculating the resulting radiation exposures and the changes with time of the contamination and radiation fields. Kerma rates at various locations in tropical urban areas are given, and the contribution of different contaminated surfaces to these rates after dry or wet deposition are discussed. (orig.). With 6 figs., 12 tabs

  11. Modeling urban expansion in Yangon, Myanmar using Landsat time-series and stereo GeoEye Images

    Science.gov (United States)

    Sritarapipat, Tanakorn; Takeuchi, Wataru

    2016-06-01

    This research proposed a methodology to model the urban expansion based dynamic statistical model using Landsat and GeoEye Images. Landsat Time-Series from 1978 to 2010 have been applied to extract land covers from the past to the present. Stereo GeoEye Images have been employed to obtain the height of the building. The class translation was obtained by observing land cover from the past to the present. The height of the building can be used to detect the center of the urban area (mainly commercial area). It was assumed that the class translation and the distance of multi-centers of the urban area also the distance of the roads affect the urban growth. The urban expansion model based on the dynamic statistical model was defined to refer to three factors; (1) the class translation, (2) the distance of the multicenters of the urban areas, and (3) the distance from the roads. Estimation and prediction of urban expansion by using our model were formulated and expressed in this research. The experimental area was set up in Yangon, Myanmar. Since it is the major of country's economic with more than five million population and the urban areas have rapidly increased. The experimental results indicated that our model of urban expansion estimated urban growth in both estimation and prediction steps in efficiency.

  12. Development and validation of a physics-based urban fire spread model

    OpenAIRE

    HIMOTO, Keisuke; TANAKA, Takeyoshi

    2008-01-01

    A computational model for fire spread in a densely built urban area is developed. The model is distinct from existing models in that it explicitly describes fire spread phenomena with physics-based knowledge achieved in the field of fire safety engineering. In the model, urban fire is interpreted as an ensemble of multiple building fires; that is, the fire spread is simulated by predicting behaviors of individual building fires under the thermal influence of neighboring building fires. Adopte...

  13. Estimating the Impact of Urbanization on Air Quality in China Using Spatial Regression Models

    Directory of Open Access Journals (Sweden)

    Chuanglin Fang

    2015-11-01

    Full Text Available Urban air pollution is one of the most visible environmental problems to have accompanied China’s rapid urbanization. Based on emission inventory data from 2014, gathered from 289 cities, we used Global and Local Moran’s I to measure the spatial autorrelation of Air Quality Index (AQI values at the city level, and employed Ordinary Least Squares (OLS, Spatial Lag Model (SAR, and Geographically Weighted Regression (GWR to quantitatively estimate the comprehensive impact and spatial variations of China’s urbanization process on air quality. The results show that a significant spatial dependence and heterogeneity existed in AQI values. Regression models revealed urbanization has played an important negative role in determining air quality in Chinese cities. The population, urbanization rate, automobile density, and the proportion of secondary industry were all found to have had a significant influence over air quality. Per capita Gross Domestic Product (GDP and the scale of urban land use, however, failed the significance test at 10% level. The GWR model performed better than global models and the results of GWR modeling show that the relationship between urbanization and air quality was not constant in space. Further, the local parameter estimates suggest significant spatial variation in the impacts of various urbanization factors on air quality.

  14. Comprehensive Regional Modeling for Long-Range Planning: Linking Integrated Urban Models and Geographic Information Systems

    OpenAIRE

    Johnston, Robert; de la Barra, Thomas

    2000-01-01

    This study demonstrates the sequential linking of two types of models to permit the comprehensive evaluation of regional transportation and land use policies. First, we operate an integrated urban model (TRANUS), which represents both land and travel markets with zones and networks. The travel and land use projections from TRANUS are outlined, to demonstrate the general reasonableness of the results, as this is the first application of a market-based urban model in the US. Second, the land us...

  15. Physics-based statistical model and simulation method of RF propagation in urban environments

    Science.gov (United States)

    Pao, Hsueh-Yuan; Dvorak, Steven L.

    2010-09-14

    A physics-based statistical model and simulation/modeling method and system of electromagnetic wave propagation (wireless communication) in urban environments. In particular, the model is a computationally efficient close-formed parametric model of RF propagation in an urban environment which is extracted from a physics-based statistical wireless channel simulation method and system. The simulation divides the complex urban environment into a network of interconnected urban canyon waveguides which can be analyzed individually; calculates spectral coefficients of modal fields in the waveguides excited by the propagation using a database of statistical impedance boundary conditions which incorporates the complexity of building walls in the propagation model; determines statistical parameters of the calculated modal fields; and determines a parametric propagation model based on the statistical parameters of the calculated modal fields from which predictions of communications capability may be made.

  16. Modeling e-logistics for urban B2C in Europe

    OpenAIRE

    Galván, Dante; Robusté Antón, Francesc; Estrada Romeu, Miguel Ángel; Campos Cacheda, Jose Magin

    2005-01-01

    Major cities need to carry out good delivery operations that coexist with the rest of urban functions. The efficiency in city organisation depends directly on the proper management of logistic networks. In this context, Urban Logistics is born to improve the efficiency in public facilities dealing with the organisation of supply networks, especially in urban freight transport networks. This paper quantitatively models supply chains in the vehicle routing problem with time windows, especially ...

  17. Modelling the impact of implementing Water Sensitive Urban Design on at a catchment scale

    DEFF Research Database (Denmark)

    Locatelli, Luca; Gabriel, S.; Bockhorn, Britta

    Stormwater management using Water Sensitive Urban Design (WSUD) is expected to be part of future drainage systems. This project aimed to develop a set of hydraulic models of the Harrestrup Å catchment (close to Copenhagen) in order to demonstrate the importance of modeling WSUDs at different scales......, ranging from models of an individual soakaway up to models of a large urban catchment. The models were developed in Mike Urban with a new integrated soakaway model. A small-scale individual soakaway model was used to determine appropriate initial conditions for soakway models. This model was applied...

  18. Model developments in TERRA_URB, the upcoming standard urban parametrization of the atmospheric numerical model COSMO(-CLM)

    Science.gov (United States)

    Wouters, Hendrik; Blahak, Ulrich; Helmert, Jürgen; Raschendorfer, Matthias; Demuzere, Matthias; Fay, Barbara; Trusilova, Kristina; Mironov, Dmitrii; Reinert, Daniel; Lüthi, Daniel; Machulskaya, Ekaterina

    2015-04-01

    In order to address urban climate at the regional scales, a new efficient urban land-surface parametrization TERRA_URB has been developed and coupled to the atmospheric numerical model COSMO-CLM. Hereby, several new advancements for urban land-surface models are introduced which are crucial for capturing the urban surface-energy balance and its seasonal dependency in the mid-latitudes. This includes a new PDF-based water-storage parametrization for impervious land, the representation of radiative absorption and emission by greenhouse gases in the infra-red spectrum in the urban canopy layer, and the inclusion of heat emission from human activity. TERRA_URB has been applied in offline urban-climate studies during European observation campaigns at Basel (BUBBLE), Toulouse (CAPITOUL), and Singapore, and currently applied in online studies for urban areas in Belgium, Germany, Switzerland, Helsinki, Singapore, and Melbourne. Because of its computational efficiency, high accuracy and its to-the-point conceptual easiness, TERRA_URB has been selected to become the standard urban parametrization of the atmospheric numerical model COSMO(-CLM). This allows for better weather forecasts for temperature and precipitation in cities with COSMO, and an improved assessment of urban outdoor hazards in the context of global climate change and urban expansion with COSMO-CLM. We propose additional extensions to TERRA_URB towards a more robust representation of cities over the world including their structural design. In a first step, COSMO's standard EXTernal PARarameter (EXTPAR) tool is updated for representing the cities into the land cover over the entire globe. Hereby, global datasets in the standard EXTPAR tool are used to retrieve the 'Paved' or 'sealed' surface Fraction (PF) referring to the presence of buildings and streets. Furthermore, new global data sets are incorporated in EXTPAR for describing the Anthropogenic Heat Flux (AHF) due to human activity, and optionally the

  19. Multi-scale dynamic modeling of atmospheric pollution in urban environment

    International Nuclear Information System (INIS)

    Thouron, Laetitia

    2017-01-01

    Urban air pollution has been identified as an important cause of health impacts, including premature deaths. In particular, ambient concentrations of gaseous pollutants such as nitrogen dioxide (NO 2 ) and particulate matter (PM10 and PM2.5) are regulated, which means that emission reduction strategies must be put in place to reduce these concentrations in places where the corresponding regulations are not respected. Besides, air pollution can contribute to the contamination of other media, for example through the contribution of atmospheric deposition to runoff contamination. The multifactorial and multi-scale aspects of urban make the pollution sources difficult to identify. Indeed, the urban environment is a heterogeneous space characterized by complex architectural structures (old buildings alongside a more modern building, residential, commercial, industrial zones, roads, etc.), non-uniform atmospheric pollutant emissions and therefore the population exposure to pollution is variable in space and time. The modeling of urban air pollution aims to understand the origin of pollutants, their spatial extent and their concentration/deposition levels. Some pollutants have long residence times and can stay several weeks in the atmosphere (PM2.5) and therefore be transported over long distances, while others are more local (NO x in the vicinity of traffic). The spatial distribution of a pollutant will therefore depend on several factors, and in particular on the surfaces encountered. Air quality depends strongly on weather, buildings (canyon-street) and emissions. The aim of this thesis is to address some of these aspects by modeling: (1) urban background pollution with a transport-chemical model (Polyphemus / POLAIR3D), which makes it possible to estimate atmospheric pollutants by type of urban surfaces (roofs, walls and roadways), (2) street-level pollution by explicitly integrating the effects of the building in a three-dimensional way with a multi-scale model of

  20. Evaluation of Seasonal, ANN, and Hybrid Models in Modeling Urban Water Consumption A Case Study of Rash City

    Directory of Open Access Journals (Sweden)

    Seyed Nematollah Mousavi

    2016-09-01

    Full Text Available Forecasting future water consumption in cities to plan for the required capacities in urban water supply systems (including water transmission networks and water treatment facilities depends on the application of behavioral models of uban water consumption. Being located in the North-South corridor, Rasht City is assuming a new role to play in the national economy as a foreign trade center. It will, thus, be necessary to review its present urban infrastructure in order to draft the required infrastructural development plans for meeting the city’s future water demands. The three Seasonal Autoregressive Integrated Moving Average (SARIMA, Artificial Neural Network (ANN, and SARIMABP approaches were employed in present study to model and forecast Rasht urban water consumption using monthly time series for the period 2001‒2008 of urban water consumption in Rasht. The seasonal unit root test was applied to develop the relevant SARIMA model. Results showed that all the seasonal and non-seasonal unit roots are present in all the frequencies in the monthly time series for Rasht urban water consumption. Using a proper filter, the SAIMA patterns were estimated. In a second stage the SARIMA output was used to determine the ANN output and the hybrid SARIMABP structure was accordingly constructed. The values for Rasht urban water consumption predicted by the three models indicated the superiority of the SARIMABP hybrid model as evidenced by the forecast error index of 0.41% obtained for this model. The other two models of SARIMA and ANN were, however, found to yield acceptable results for urban water managers since the forecasting error recorded for them was below 1%.

  1. A spatial multi-objective optimization model for sustainable urban wastewater system layout planning.

    Science.gov (United States)

    Dong, X; Zeng, S; Chen, J

    2012-01-01

    Design of a sustainable city has changed the traditional centralized urban wastewater system towards a decentralized or clustering one. Note that there is considerable spatial variability of the factors that affect urban drainage performance including urban catchment characteristics. The potential options are numerous for planning the layout of an urban wastewater system, which are associated with different costs and local environmental impacts. There is thus a need to develop an approach to find the optimal spatial layout for collecting, treating, reusing and discharging the municipal wastewater of a city. In this study, a spatial multi-objective optimization model, called Urban wastewateR system Layout model (URL), was developed. It is solved by a genetic algorithm embedding Monte Carlo sampling and a series of graph algorithms. This model was illustrated by a case study in a newly developing urban area in Beijing, China. Five optimized system layouts were recommended to the local municipality for further detailed design.

  2. High-resolution flood modeling of urban areas using MSN_Flood

    Directory of Open Access Journals (Sweden)

    Michael Hartnett

    2017-07-01

    Full Text Available Although existing hydraulic models have been used to simulate and predict urban flooding, most of these models are inadequate due to the high spatial resolution required to simulate flows in urban floodplains. Nesting high-resolution subdomains within coarser-resolution models is an efficient solution for enabling simultaneous calculation of flooding due to tides, surges, and high river flows. MSN_Flood has been developed to incorporate moving boundaries around nested domains, permitting alternate flooding and drying along the boundary and in the interior of the domain. Ghost cells adjacent to open boundary cells convert open boundaries, in effect, into internal boundaries. The moving boundary may be multi-segmented and non-continuous, with recirculating flow across the boundary. When combined with a bespoke adaptive interpolation scheme, this approach facilitates a dynamic internal boundary. Based on an alternating-direction semi-implicit finite difference scheme, MSN_Flood was used to hindcast a major flood event in Cork City resulting from the combined pressures of fluvial, tidal, and storm surge processes. The results show that the model is computationally efficient, as the 2-m high-resolution nest is used only in the urban flooded region. Elsewhere, lower-resolution nests are used. The results also show that the model is highly accurate when compared with measured data. The model is capable of incorporating nested sub-domains when the nested boundary is multi-segmented and highly complex with lateral gradients of elevation and velocities. This is a major benefit when modelling urban floodplains at very high resolution.

  3. PALM-USM v1.0: A new urban surface model integrated into the PALM large-eddy simulation model

    Directory of Open Access Journals (Sweden)

    J. Resler

    2017-10-01

    Full Text Available Urban areas are an important part of the climate system and many aspects of urban climate have direct effects on human health and living conditions. This implies that reliable tools for local urban climate studies supporting sustainable urban planning are needed. However, a realistic implementation of urban canopy processes still poses a serious challenge for weather and climate modelling for the current generation of numerical models. To address this demand, a new urban surface model (USM, describing the surface energy processes for urban environments, was developed and integrated as a module into the PALM large-eddy simulation model. The development of the presented first version of the USM originated from modelling the urban heat island during summer heat wave episodes and thus implements primarily processes important in such conditions. The USM contains a multi-reflection radiation model for shortwave and longwave radiation with an integrated model of absorption of radiation by resolved plant canopy (i.e. trees, shrubs. Furthermore, it consists of an energy balance solver for horizontal and vertical impervious surfaces, and thermal diffusion in ground, wall, and roof materials, and it includes a simple model for the consideration of anthropogenic heat sources. The USM was parallelized using the standard Message Passing Interface and performance testing demonstrates that the computational costs of the USM are reasonable on typical clusters for the tested configurations. The module was fully integrated into PALM and is available via its online repository under the GNU General Public License (GPL. The USM was tested on a summer heat-wave episode for a selected Prague crossroads. The general representation of the urban boundary layer and patterns of surface temperatures of various surface types (walls, pavement are in good agreement with in situ observations made in Prague. Additional simulations were performed in order to assess the

  4. Constructing an Urban Population Model for Medical Insurance Scheme Using Microsimulation Techniques

    Directory of Open Access Journals (Sweden)

    Linping Xiong

    2012-01-01

    Full Text Available China launched a pilot project of medical insurance reform in 79 cities in 2007 to cover urban nonworking residents. An urban population model was created in this paper for China’s medical insurance scheme using microsimulation model techniques. The model made it clear for the policy makers the population distributions of different groups of people, the potential urban residents entering the medical insurance scheme. The income trends of units of individuals and families were also obtained. These factors are essential in making the challenging policy decisions when considering to balance the long-term financial sustainability of the medical insurance scheme.

  5. Modeling urbanization patterns at a global scale with generative adversarial networks

    Science.gov (United States)

    Albert, A. T.; Strano, E.; Gonzalez, M.

    2017-12-01

    Current demographic projections show that, in the next 30 years, global population growth will mostly take place in developing countries. Coupled with a decrease in density, such population growth could potentially double the land occupied by settlements by 2050. The lack of reliable and globally consistent socio-demographic data, coupled with the limited predictive performance underlying traditional urban spatial explicit models, call for developing better predictive methods, calibrated using a globally-consistent dataset. Thus, richer models of the spatial interplay between the urban built-up land, population distribution and energy use are central to the discussion around the expansion and development of cities, and their impact on the environment in the context of a changing climate. In this talk we discuss methods for, and present an analysis of, urban form, defined as the spatial distribution of macroeconomic quantities that characterize a city, using modern machine learning methods and best-available remote-sensing data for the world's largest 25,000 cities. We first show that these cities may be described by a small set of patterns in radial building density, nighttime luminosity, and population density, which highlight, to first order, differences in development and land use across the world. We observe significant, spatially-dependent variance around these typical patterns, which would be difficult to model using traditional statistical methods. We take a first step in addressing this challenge by developing CityGAN, a conditional generative adversarial network model for simulating realistic urban forms. To guide learning and measure the quality of the simulated synthetic cities, we develop a specialized loss function for GAN optimization that incorporates standard spatial statistics used by urban analysis experts. Our framework is a stark departure from both the standard physics-based approaches in the literature (that view urban forms as fractals with a

  6. Effects of electro-fishing on galvano-taxis and carcass quality characteristics in sea bass (Dicentrarchus labrax

    Directory of Open Access Journals (Sweden)

    Edo D’Agaro

    2010-01-01

    Full Text Available The aim of this study was to investigate the effects of electro-fishing in sea water. We evaluated the feasibility of an electro-fishing system using numerical simulations for laboratory tanks and the open sea and performing a laboratory experiment. A non-homogeneous bi-dimensional electric-field model for marine water and fish based on discrete formulation of electro-magnetic field equations was developed using GAME (geometric approach for Maxwell equations software. Voltage gradients inside the fish and close to the body were determined. Re- sults showed that fish in the open sea and in groups had greater internal voltage differences than did fish in tanks and single fish. Sea bass (length:10 and 30 cm were exposed in laboratory tanks to pulsed direct current (PDC, 25-125 Hz and duty cycle (5-40%. We measured the electro-taxis and tetanus thresholds after electrical exposure. It is significant that these values decreased with increasing the size of fish. No differences were found after electro-fishing on overall appearance, internal and external haemorrhage, standard freshness scoring techniques and carcass quality characteristics

  7. CityZoom UP (Urban Pollution): a computational tool for the fast generation and setup of urban scenarios for CFD and dispersion modelling simulation

    OpenAIRE

    Grazziotin, Pablo Colossi

    2016-01-01

    This research presents the development of CityZoom UP, the first attempt to extend existing urban planning software in order to assist in modelling urban scenarios and setting up simulation parameters for Gaussian dispersion and CFD models. Based on the previous capabilities and graphic user interfaces of CityZoom to model and validate urban scenarios based on Master Plan regulations, new graphic user interfaces, automatic mesh generation and data conversion algorithms have been created to se...

  8. Modeling the effect of urban infrastructure on hydrologic processes within i-Tree Hydro, a statistically and spatially distributed model

    Science.gov (United States)

    Taggart, T. P.; Endreny, T. A.; Nowak, D.

    2014-12-01

    Gray and green infrastructure in urban environments alters many natural hydrologic processes, creating an urban water balance unique to the developed environment. A common way to assess the consequences of impervious cover and grey infrastructure is by measuring runoff hydrographs. This focus on the watershed outlet masks the spatial variation of hydrologic process alterations across the urban environment in response to localized landscape characteristics. We attempt to represent this spatial variation in the urban environment using the statistically and spatially distributed i-Tree Hydro model, a scoping level urban forest effects water balance model. i-Tree Hydro has undergone expansion and modification to include the effect of green infrastructure processes, road network attributes, and urban pipe system leakages. These additions to the model are intended to increase the understanding of the altered urban hydrologic cycle by examining the effects of the location of these structures on the water balance. Specifically, the effect of these additional structures and functions on the spatially varying properties of interception, soil moisture and runoff generation. Differences in predicted properties and optimized parameter sets between the two models are examined and related to the recent landscape modifications. Datasets used in this study consist of watersheds and sewersheds within the Syracuse, NY metropolitan area, an urban area that has integrated green and gray infrastructure practices to alleviate stormwater problems.

  9. Modelling carbon dynamics from urban land conversion: fundamental model of city in relation to a local carbon cycle

    Directory of Open Access Journals (Sweden)

    Schellnhuber Hans-Joachim

    2006-08-01

    Full Text Available Abstract Background The main task is to estimate the qualitative and quantitative contribution of urban territories and precisely of the process of urbanization to the Global Carbon Cycle (GCC. Note that, on the contrary to many investigations that have considered direct anthropogenic emission of CO2(urbanized territories produce ca. 96–98% of it, we are interested in more subtle, and up until the present time, weaker processes associated with the conversion of the surrounding natural ecosystems and landscapes into urban lands. Such conversion inevitably takes place when cities are sprawling and additional "natural" lands are becoming "urbanized". Results In order to fulfil this task, we first develop a fundamental model of urban space, since the type of land cover within a city makes a difference for a local carbon cycle. Hence, a city is sub-divided by built-up, „green" (parks, etc. and informal settlements (favelas fractions. Another aspect is a sub-division of the additional two regions, which makes the total number reaching eight regions, while the UN divides the world by six. Next, the basic model of the local carbon cycle for urbanized territories is built. We consider two processes: carbon emissions as a result of conversion of natural lands caused by urbanization; and the transformation of carbon flows by "urbanized" ecosystems; when carbon, accumulated by urban vegetation, is exported to the neighbouring territories. The total carbon flow in the model depends, in general, on two groups of parameters. The first includes the NPP, and the sum of living biomass and dead organic matter of ecosystems involved in the process of urbanization, and namely them we calculate here, using a new more realistic approach and taking into account the difference in regional cities' evolution. Conclusion There is also another group of parameters, dealing with the areas of urban territories, and their annual increments. A method of dynamic forecasting

  10. [Employment and urban growth; an application of Czamanski's model to the Mexican case].

    Science.gov (United States)

    Verduzco Chavez, B

    1991-01-01

    The author applies the 1964 model developed by Stanislaw Czamanski, based on theories of urban growth and industrial localization, to the analysis of urban growth in Mexico. "The advantages of this model in its application as a support instrument in the process of urban planning when the information available is incomplete are...discussed...." Census data for 44 cities in Mexico are used. (SUMMARY IN ENG) excerpt

  11. A Remote Sensing-based Characterization of the Urban Heat Island and its Implications for Modeled Estimates of Urban Biogenic Carbon Fluxes in Boston, MA.

    Science.gov (United States)

    Wang, J.; Friedl, M. A.; Hutyra, L.; Hardiman, B. S.

    2015-12-01

    Urban land use occupies a small but critical proportion of global land area for the carbon cycle, and in the coming decades, urban land area is expected to nearly double. Conversion of natural land cover to urban land cover imposes myriad ecological effects, including increased land surface and air temperatures via the urban heat island effect. In this study, we characterize the seasonal and spatial characteristics of the urban heat island over Boston, MA and estimate its consequences on biogenic carbon fluxes with a remote sensing-based model. Using a 12-year time series of emissivity- and atmospherically-corrected land surface temperatures from Landsat TM and ETM+ imagery, we find a high degree of spatial heterogeneity and consistent seasonal patterns in the thermal properties of Boston, controlled mainly by variations in vegetative cover. Field measurements of surface air temperature across an urbanization gradient show season- and vegetation-dependent patterns consistent with those observed in the Landsat data. With a fused data set that combines surface air temperature, MODIS, and Landsat observations, we modify and run the Vegetation Photosynthesis and Respiration Model (VPRM) to explore 1) how elevated temperatures affect diurnal and seasonal patterns of hourly urban biogenic carbon fluxes in Massachusetts in 2013 and 2014 and 2) to what extent these fluxes follow spatial patterns found in the urban heat island. Model modifications simulate the ecological effects of urbanization, including empirical adjustments to reanalysis-driven air temperatures (up to 5 K) and ecosystem respiration reduced by impervious surface area. Model results reveal spatio-temporal patterns consistent with strong land use and vegetation cover controls on biogenic carbon fluxes, with non-trivial biogenic annual net ecosystem exchange occurring in urban and suburban areas (up to -2.5 MgC/ha/yr). We specifically consider the feedbacks between Boston's urban heat island and landscape

  12. An urban runoff model designed to inform stormwater management decisions.

    Science.gov (United States)

    Beck, Nicole G; Conley, Gary; Kanner, Lisa; Mathias, Margaret

    2017-05-15

    We present an urban runoff model designed for stormwater managers to quantify runoff reduction benefits of mitigation actions that has lower input data and user expertise requirements than most commonly used models. The stormwater tool to estimate load reductions (TELR) employs a semi-distributed approach, where landscape characteristics and process representation are spatially-lumped within urban catchments on the order of 100 acres (40 ha). Hydrologic computations use a set of metrics that describe a 30-year rainfall distribution, combined with well-tested algorithms for rainfall-runoff transformation and routing to generate average annual runoff estimates for each catchment. User inputs include the locations and specifications for a range of structural best management practice (BMP) types. The model was tested in a set of urban catchments within the Lake Tahoe Basin of California, USA, where modeled annual flows matched that of the observed flows within 18% relative error for 5 of the 6 catchments and had good regional performance for a suite of performance metrics. Comparisons with continuous simulation models showed an average of 3% difference from TELR predicted runoff for a range of hypothetical urban catchments. The model usually identified the dominant BMP outflow components within 5% relative error of event-based measured flow data and simulated the correct proportionality between outflow components. TELR has been implemented as a web-based platform for use by municipal stormwater managers to inform prioritization, report program benefits and meet regulatory reporting requirements (www.swtelr.com). Copyright © 2017. Published by Elsevier Ltd.

  13. Modeling Impact of Urbanization in US Cities Using Simple Biosphere Model SiB2

    Science.gov (United States)

    Zhang, Ping; Bounoua, Lahouari; Thome, Kurtis; Wolfe, Robert

    2016-01-01

    We combine Landsat- and the Moderate Resolution Imaging Spectroradiometer (MODIS)-based products, as well as climate drivers from Phase 2 of the North American Land Data Assimilation System (NLDAS-2) in a Simple Biosphere land surface model (SiB2) to assess the impact of urbanization in continental USA (excluding Alaska and Hawaii). More than 300 cities and their surrounding suburban and rural areas are defined in this study to characterize the impact of urbanization on surface climate including surface energy, carbon budget, and water balance. These analyses reveal an uneven impact of urbanization across the continent that should inform upon policy options for improving urban growth including heat mitigation and energy use, carbon sequestration and flood prevention.

  14. High-resolution urban flood modelling - a joint probability approach

    Science.gov (United States)

    Hartnett, Michael; Olbert, Agnieszka; Nash, Stephen

    2017-04-01

    The hydrodynamic modelling of rapid flood events due to extreme climatic events in urban environment is both a complex and challenging task. The horizontal resolution necessary to resolve complexity of urban flood dynamics is a critical issue; the presence of obstacles of varying shapes and length scales, gaps between buildings and the complex geometry of the city such as slopes affect flow paths and flood levels magnitudes. These small scale processes require a high resolution grid to be modelled accurately (2m or less, Olbert et al., 2015; Hunter et al., 2008; Brown et al., 2007) and, therefore, altimetry data of at least the same resolution. Along with availability of high-resolution LiDAR data and computational capabilities, as well as state of the art nested modelling approaches, these problems can now be overcome. Flooding and drying, domain definition, frictional resistance and boundary descriptions are all important issues to be addressed when modelling urban flooding. In recent years, the number of urban flood models dramatically increased giving a good insight into various modelling problems and solutions (Mark et al., 2004; Mason et al., 2007; Fewtrell et al., 2008; Shubert et al., 2008). Despite extensive modelling work conducted for fluvial (e.g. Mignot et al., 2006; Hunter et al., 2008; Yu and Lane, 2006) and coastal mechanisms of flooding (e.g. Gallien et al., 2011; Yang et al., 2012), the amount of investigations into combined coastal-fluvial flooding is still very limited (e.g. Orton et al., 2012; Lian et al., 2013). This is surprising giving the extent of flood consequences when both mechanisms occur simultaneously, which usually happens when they are driven by one process such as a storm. The reason for that could be the fact that the likelihood of joint event is much smaller than those of any of the two contributors occurring individually, because for fast moving storms the rainfall-driven fluvial flood arrives usually later than the storm surge

  15. Beyond urban penalty and urban sprawl: back to living conditions as the focus of urban health.

    Science.gov (United States)

    Freudenberg, Nicholas; Galea, Sandro; Vlahov, David

    2005-02-01

    Researchers have long studied urban health, both to describe the consequences of urban living and to design interventions to promote the health of people living in cities. Two approaches to understanding the impact of cities on health have been dominant, namely, urban health penalty and urban sprawl. The urban penalty approach posits that cities concentrate poor people and expose them to unhealthy physical and social environments. Urban sprawl focuses on the adverse health and environmental effects of urban growth into outlying areas. We propose a model that integrates these approaches and emphasizes urban living conditions as the primary determinant of health. The aim of the model is to move beyond describing the health-related characteristics of various urban populations towards identifying opportunities for intervention. Such a shift in framework enables meaningful comparisons that can inform public health activities at the appropriate level and evaluate their effectiveness in improving the health of urban populations. The model is illustrated with two examples from current urban public health practice.

  16. Urban Noise Modelling in Boka Kotorska Bay

    Directory of Open Access Journals (Sweden)

    Aleksandar Nikolić

    2014-04-01

    Full Text Available Traffic is the most significant noise source in urban areas. The village of Kamenari in Boka Kotorska Bay is a site where, in a relatively small area, road traffic and sea (ferry traffic take place at the same time. Due to the specificity of the location, i.e. very rare synergy of sound effects of road and sea traffic in the urban area, as well as the expressed need for assessment of noise level in a simple and quick way, a research was conducted, using empirical methods and statistical analysis methods, which led to the creation of acoustic model for the assessment of equivalent noise level (Leq. The developed model for noise assessment in the Village of Kamenari in Boka Kotorska Bay quite realistically provides data on possible noise levels at the observed site, with very little deviations in relation to empirically obtained values.

  17. Using urban forest assessment tools to model bird habitat potential

    Science.gov (United States)

    Lerman, Susannah B.; Nislow, Keith H.; Nowak, David J.; DeStefano, Stephen; King, David I.; Jones-Farrand, D. Todd

    2014-01-01

    The alteration of forest cover and the replacement of native vegetation with buildings, roads, exotic vegetation, and other urban features pose one of the greatest threats to global biodiversity. As more land becomes slated for urban development, identifying effective urban forest wildlife management tools becomes paramount to ensure the urban forest provides habitat to sustain bird and other wildlife populations. The primary goal of this study was to integrate wildlife suitability indices to an existing national urban forest assessment tool, i-Tree. We quantified available habitat characteristics of urban forests for ten northeastern U.S. cities, and summarized bird habitat relationships from the literature in terms of variables that were represented in the i-Tree datasets. With these data, we generated habitat suitability equations for nine bird species representing a range of life history traits and conservation status that predicts the habitat suitability based on i-Tree data. We applied these equations to the urban forest datasets to calculate the overall habitat suitability for each city and the habitat suitability for different types of land-use (e.g., residential, commercial, parkland) for each bird species. The proposed habitat models will help guide wildlife managers, urban planners, and landscape designers who require specific information such as desirable habitat conditions within an urban management project to help improve the suitability of urban forests for birds.

  18. a Quadtree Organization Construction and Scheduling Method for Urban 3d Model Based on Weight

    Science.gov (United States)

    Yao, C.; Peng, G.; Song, Y.; Duan, M.

    2017-09-01

    The increasement of Urban 3D model precision and data quantity puts forward higher requirements for real-time rendering of digital city model. Improving the organization, management and scheduling of 3D model data in 3D digital city can improve the rendering effect and efficiency. This paper takes the complexity of urban models into account, proposes a Quadtree construction and scheduling rendering method for Urban 3D model based on weight. Divide Urban 3D model into different rendering weights according to certain rules, perform Quadtree construction and schedule rendering according to different rendering weights. Also proposed an algorithm for extracting bounding box extraction based on model drawing primitives to generate LOD model automatically. Using the algorithm proposed in this paper, developed a 3D urban planning&management software, the practice has showed the algorithm is efficient and feasible, the render frame rate of big scene and small scene are both stable at around 25 frames.

  19. A QUADTREE ORGANIZATION CONSTRUCTION AND SCHEDULING METHOD FOR URBAN 3D MODEL BASED ON WEIGHT

    Directory of Open Access Journals (Sweden)

    C. Yao

    2017-09-01

    Full Text Available The increasement of Urban 3D model precision and data quantity puts forward higher requirements for real-time rendering of digital city model. Improving the organization, management and scheduling of 3D model data in 3D digital city can improve the rendering effect and efficiency. This paper takes the complexity of urban models into account, proposes a Quadtree construction and scheduling rendering method for Urban 3D model based on weight. Divide Urban 3D model into different rendering weights according to certain rules, perform Quadtree construction and schedule rendering according to different rendering weights. Also proposed an algorithm for extracting bounding box extraction based on model drawing primitives to generate LOD model automatically. Using the algorithm proposed in this paper, developed a 3D urban planning&management software, the practice has showed the algorithm is efficient and feasible, the render frame rate of big scene and small scene are both stable at around 25 frames.

  20. A discrete-space urban model with environmental amenities

    Science.gov (United States)

    Liaila Tajibaeva; Robert G. Haight; Stephen Polasky

    2008-01-01

    This paper analyzes the effects of providing environmental amenities associated with open space in a discrete-space urban model and characterizes optimal provision of open space across a metropolitan area. The discrete-space model assumes distinct neighborhoods in which developable land is homogeneous within a neighborhood but heterogeneous across neighborhoods. Open...

  1. An integrated urban drainage system model for assessing renovation scheme.

    Science.gov (United States)

    Dong, X; Zeng, S; Chen, J; Zhao, D

    2012-01-01

    Due to sustained economic growth in China over the last three decades, urbanization has been on a rapidly expanding track. In recent years, regional industrial relocations were also accelerated across the country from the east coast to the west inland. These changes have led to a large-scale redesign of urban infrastructures, including the drainage system. To help the reconstructed infrastructures towards a better sustainability, a tool is required for assessing the efficiency and environmental performance of different renovation schemes. This paper developed an integrated dynamic modeling tool, which consisted of three models for describing the sewer, the wastewater treatment plant (WWTP) and the receiving water body respectively. Three auxiliary modules were also incorporated to conceptualize the model, calibrate the simulations, and analyze the results. The developed integrated modeling tool was applied to a case study in Shenzhen City, which is one of the most dynamic cities and facing considerable challenges for environmental degradation. The renovation scheme proposed to improve the environmental performance of Shenzhen City's urban drainage system was modeled and evaluated. The simulation results supplied some suggestions for the further improvement of the renovation scheme.

  2. An Integrated Model Based on a Hierarchical Indices System for Monitoring and Evaluating Urban Sustainability

    Directory of Open Access Journals (Sweden)

    Xulin Guo

    2013-02-01

    Full Text Available Over 50% of world’s population presently resides in cities, and this number is expected to rise to ~70% by 2050. Increasing urbanization problems including population growth, urban sprawl, land use change, unemployment, and environmental degradation, have markedly impacted urban residents’ Quality of Life (QOL. Therefore, urban sustainability and its measurement have gained increasing attention from administrators, urban planners, and scientific communities throughout the world with respect to improving urban development and human well-being. The widely accepted definition of urban sustainability emphasizes the balancing development of three primary domains (urban economy, society, and environment. This article attempts to improve the aforementioned definition of urban sustainability by incorporating a human well-being dimension. Major problems identified in existing urban sustainability indicator (USI models include a weak integration of potential indicators, poor measurement and quantification, and insufficient spatial-temporal analysis. To tackle these challenges an integrated USI model based on a hierarchical indices system was established for monitoring and evaluating urban sustainability. This model can be performed by quantifying indicators using both traditional statistical approaches and advanced geomatic techniques based on satellite imagery and census data, which aims to provide a theoretical basis for a comprehensive assessment of urban sustainability from a spatial-temporal perspective.

  3. Characterization and spatial modeling of urban sprawl in the Wuhan Metropolitan Area, China

    Science.gov (United States)

    Zeng, Chen; Liu, Yaolin; Stein, Alfred; Jiao, Limin

    2015-02-01

    Urban sprawl has led to environmental problems and large losses of arable land in China. In this study, we monitor and model urban sprawl by means of a combination of remote sensing, geographical information system and spatial statistics. We use time-series data to explore the potential socio-economic driving forces behind urban sprawl, and spatial models in different scenarios to explore the spatio-temporal interactions. The methodology is applied to the city of Wuhan, China, for the period from 1990 to 2013. The results reveal that the built-up land has expanded and has dispersed in urban clusters. Population growth, and economic and transportation development are still the main causes of urban sprawl; however, when they have developed to certain levels, the area affected by construction in urban areas (Jian Cheng Qu (JCQ)) and the area of cultivated land (ACL) tend to be stable. Spatial regression models are shown to be superior to the traditional models. The interaction among districts with the same administrative status is stronger than if one of those neighbors is in the city center and the other in the suburban area. The expansion of urban built-up land is driven by the socio-economic development at the same period, and greatly influenced by its spatio-temporal neighbors. We conclude that the integration of remote sensing, a geographical information system, and spatial statistics offers an excellent opportunity to explore the spatio-temporal variation and interactions among the districts in the sprawling metropolitan areas. Relevant regulations to control the urban sprawl process are suggested accordingly.

  4. Strategic management in urban environment using SWOT and QSPM model

    Directory of Open Access Journals (Sweden)

    M. Pazouki

    2017-04-01

    Full Text Available Sustainable urban development is a new concept of fundamental environmental metropolitan management that not only creates the demand for changing the concepts of economic development, but also affects social development. The current study  provides  a conceptual model of a sustainable environment pattern In District 22 of Tehran that depends on the relationship between environment and economy, and a network of urban function, which  Included transport infrastructure and community centers and economic and regional level in support of the ecological services in Tehran. This landscape often  had discrepancies  with the development of the city between the layers and the creation of ecological fragile areas. The main objective of the study was to determine the sustainability indicators and create a future development  model  for District 22 of Tehran. The data was collected by having a review of similar studies and field research on the subject and therefore the effective factors were identified. After accomplished proceedings, the questionnaire was prepared and the results were used in SWOT charts' grading after analyzing at interior and exterior matrix. Ultimately, quantitative strategic planning matrix (QSPM was performed based on the results and analysis. This process provided a comprehensive model for sustainable urban development as sustainable development urban landscape pattern.

  5. A Study of the Oklahoma City Urban Heat Island Effect Using a WRF/Single-Layer Urban Canopy Model, a Joint Urban 2003 Field Campaign, and MODIS Satellite Observations

    Directory of Open Access Journals (Sweden)

    Hengyue Zhang

    2017-09-01

    Full Text Available The urban heat island effect (UHI for inner land regions was investigated using satellite data, ground observations, and simulations with an Single-Layer Urban Canopy Parameterization (SLUCP coupled into the regional Weather Research Forecasting model (WRF, http://wrf-model.org/index.php. Specifically, using the satellite-observed surface skin temperatures (Tskin, the intensity of the UHI was first compared for two inland cities (Xi’an City, China, and Oklahoma City (OKC, which have different city populations and building densities. The larger population density and larger building density in Xi’an lead to a stronger skin-level UHI by 2 °C. However, the ground observed 2 m surface air temperature (Tair observations showed an urban cooling island effect (UCI over the downtown region in OKC during the daytime of 19 July 2003, from a DOE field campaign (Joint Urban 2003. To understand this contrast between satellite-based Tskin and ground-based Tair, a sensitivity study using WRF/SLUCP was analyzed. The model reproduced a UCI in OKC. Furthermore, WRF/Noah/SLUCM simulations were also compared with the Joint Urban 2003 ground observations, including wind speeds, wind directions, and energy fluxes. Although the WRF/SLUCM model failed to simulate these variables accurately, it reproduced the diurnal variations of surface temperatures, wind speeds, wind directions, and energy fluxes reasonably well.

  6. The impact of urban open space and 'lift-up' building design on building intake fraction and daily pollutant exposure in idealized urban models.

    Science.gov (United States)

    Sha, Chenyuan; Wang, Xuemei; Lin, Yuanyuan; Fan, Yifan; Chen, Xi; Hang, Jian

    2018-08-15

    Sustainable urban design is an effective way to improve urban ventilation and reduce vehicular pollutant exposure to urban residents. This paper investigated the impacts of urban open space and 'lift-up' building design on vehicular CO (carbon monoxide) exposure in typical three-dimensional (3D) urban canopy layer (UCL) models under neutral atmospheric conditions. The building intake fraction (IF) represents the fraction of total vehicular pollutant emissions inhaled by residents when they stay at home. The building daily CO exposure (E t ) means the extent of human beings' contact with CO within one day indoor at home. Computational fluid dynamics (CFD) simulations integrating with these two concepts were performed to solve turbulent flow and assess vehicular CO exposure to urban residents. CFD technique with the standard k-ε model was successfully validated by wind tunnel data. The initial numerical UCL model consists of 5-row and 5-column (5×5) cubic buildings (building height H=street width W=30m) with four approaching wind directions (θ=0°, 15°, 30°, 45°). In Group I, one of the 25 building models is removed to attain urban open space settings. In Group II, the first floor (Lift-up1), or second floor (Lift-up2), or third floor (Lift-up3) of all buildings is elevated respectively to create wind pathways through buildings. Compared to the initial case, urban open space can slightly or significantly reduce pollutant exposure for urban residents. As θ=30° and 45°, open space settings are more effective to reduce pollutant exposure than θ=0° and 15°.The pollutant dilution near or surrounding open space and in its adjacent downstream regions is usually enhanced. Lift-up1 and Lift-up2 experience much greater pollutant exposure reduction in all wind directions than Lift-up3 and open space. Although further investigations are still required to provide practical guidelines, this study is one of the first attempts for reducing urban pollutant exposure by

  7. Development of urban runoff model FFC-QUAL for first-flush water-quality analysis in urban drainage basins.

    Science.gov (United States)

    Hur, Sungchul; Nam, Kisung; Kim, Jungsoo; Kwak, Changjae

    2018-01-01

    An urban runoff model that is able to compute the runoff, the pollutant loadings, and the concentrations of water-quality constituents in urban drainages during the first flush was developed. This model, which is referred to as FFC-QUAL, was modified from the existing ILLUDAS model and added for use during the water-quality analysis process for dry and rainy periods. For the dry period, the specifications of the coefficients for the discharge and water quality were used. During rainfall, we used the Clark and time-area methods for the runoff analyses of pervious and impervious areas to consider the effects of the subbasin shape; moreover, four pollutant accumulation methods and the washoff equation for computing the water quality each time were used. According to the verification results, FFC-QUAL provides generally similar output as the measured data for the peak flow, total runoff volume, total loadings, peak concentration, and time of peak concentration for three rainfall events in the Gunja subbasin. In comparison with the ILLUDAS, SWMM, and MOUSE models, there is little difference between these models and the model developed in this study. The proposed model should be useful in urban watersheds because of its simplicity and its capacity to model common pollutants (e.g., biological oxygen demand, chemical oxygen demand, Escherichia coli, suspended solids, and total nitrogen and phosphorous) in runoff. The proposed model can also be used in design studies to determine how changes in infrastructure will affect the runoff and pollution loads. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  8. Predictive Modelling of Heavy Metals in Urban Lakes

    OpenAIRE

    Lindström, Martin

    2000-01-01

    Heavy metals are well-known environmental pollutants. In this thesis predictive models for heavy metals in urban lakes are discussed and new models presented. The base of predictive modelling is empirical data from field investigations of many ecosystems covering a wide range of ecosystem characteristics. Predictive models focus on the variabilities among lakes and processes controlling the major metal fluxes. Sediment and water data for this study were collected from ten small lakes in the ...

  9. Impacts of Detailed Land-Use Types and Urban Heat in an Urban Canopy Model on Local Meteorology and Ozone Levels for Air Quality Modeling in a Coastal City, Korea

    Directory of Open Access Journals (Sweden)

    Yoon-Hee Kang

    2016-01-01

    Full Text Available An urban canopy model (UCM, with detailed urban land-use and anthropogenic heat information, is required to reproduce and understand the urbanization process and its impact on regional climate and urban air quality. This study investigates the UCM impact on simulated meteorology and surface ozone in the coastal city of Busan using the WRF-SMOKE-CMAQ model coupled with (UCM case, and without the UCM (NOUCM case. The UCM and NOUCM case results suggest that UCM case generally produces warmer temperatures and deeper planetary boundary layer (PBL heights, especially in the early morning and night time, than the NOUCM case. Owing to urban heating and enhanced turbulent mixing incorporation in the center of the city, the sea breeze in the UCM case tends to penetrate faster and more strongly than in the NOUCM case. After sea breeze arrival at the urban center, the urban heat island effect prevents its penetration further inland. In the UCM case in the late afternoon, local meteorological changes induce remarkable increases in simulated O3 concentrations over the downwind (up to 17.1 ppb and downtown (up to 10.6 ppb areas. This is probably due to an increase in temperature in the urban areas and the wind convergence zone movement due to the sea breeze interaction and offshore flows. The increase in O3 concentration in the late afternoon results in the model bias reduction under previously underestimated O3 conditions due to high NOx emissions. The simulated O3 concentrations in the UCM case are more similar to the observed O3 concentrations compared to those of the NOUCM case.

  10. Traffic noise in shielded urban areas: comparison of experimental data with model results

    NARCIS (Netherlands)

    Randrianoelina, A.; Salomons, E.M.

    2008-01-01

    Noise maps of cities are commonly produced with rather simple engineering models for sound propagation. These models may be inaccurate in complex urban situations, in particular in situations with street canyons. Street canyons are urban areas that are partly or completely enclosed by buildings, for

  11. Carbon monoxide levels in popular passenger commuting modes traversing major commuting routes in Hong Kong

    International Nuclear Information System (INIS)

    Chan, L.Y.; Liu, Y.M.

    2001-01-01

    Vehicle exhaust is a major source of air pollution in metropolitan cities. Commuters are exposed to high traffic-related pollutant concentrations. Public transportation is the most popular commuting mode in Hong Kong and there are about 10.8 million passenger trips every day. Two-thirds of them are road commuters. An extensive survey was conducted to measure carbon monoxide in three popular passenger commuting modes, bus, minibus, and taxi, which served, respectively, 3.91 million, 1.76 million and 1.31 million passenger trips per day in 1998. Three types of commuting microenvironments were selected: urban-urban, urban-suburban and urban-rural. Results indicated that in-vehicle CO level increased in the following order: bus, minibus and taxi. The overall average in-vehicle CO level in air-conditioned bus, minibus and taxi were 1.8, 2.9 and 3.3ppm, respectively. The average concentration level between air-conditioned buses (1.8ppm) and non-air-conditioned buses (1.9ppm) was insignificant. The fluctuation of in-vehicle CO level of non-air-conditioned vehicle followed the variation of out-vehicle CO concentration. Our result also showed that even in air-conditioned vehicles, the in-vehicle CO concentration was affected by the out-vehicle CO concentration although there exists a smoothing out effect. The in-vehicle CO level was the highest in urban-suburban commuting routes and was followed by urban-urban routes. The in-vehicle CO level in urban-rural routes was the lowest. The highest CO level was recorded after the vehicle traversed through tunnel.. The average CO exposure level of public road transportation commuters in Honk Kong was lower than most other cities. Factors governing the CO levels were also discussed. (Author)

  12. Urban Morphology Influence on Urban Albedo: A Revisit with the S olene Model

    Science.gov (United States)

    Groleau, Dominique; Mestayer, Patrice G.

    2013-05-01

    This heuristic study of the urban morphology influence on urban albedo is based on some 3,500 simulations with the S olene model. The studied configurations include square blocks in regular and staggered rows, rectangular blocks with different street widths, cross-shaped blocks, infinite street canyons and several actual districts in Marseilles, Toulouse and Nantes, France. The scanned variables are plan density, facade density, building height, layout orientation, latitude, date and time of the day. The sky-view factors of the ground and canopy surfaces are also considered. This study demonstrates the significance of the facade density, in addition to the built plan density, as the explanatory geometrical factor to characterize the urban morphology, rather than building height. On the basis of these albedo calculations the puzzling results of Kondo et al. (Boundary-Layer Meteorol 100:225-242, 2001) for the influence of building height are explained, and the plan density influence is quantitatively assessed. It is shown that the albedo relationship with plan and facade densities obtained with the regular square plot configuration may be considered as a reference for all other configurations, with the exception of the infinite street canyon that shows systematic differences for the lower plan densities. The curves representing this empirical relationship may be used as a sort of abacus for all other geometries while an approximate simple mathematical model is proposed, as well as relationships between the albedo and sky-view factors.

  13. Parameterization of a Hydrological Model for a Large, Ungauged Urban Catchment

    Directory of Open Access Journals (Sweden)

    Gerald Krebs

    2016-10-01

    Full Text Available Urbanization leads to the replacement of natural areas by impervious surfaces and affects the catchment hydrological cycle with adverse environmental impacts. Low impact development tools (LID that mimic hydrological processes of natural areas have been developed and applied to mitigate these impacts. Hydrological simulations are one possibility to evaluate the LID performance but the associated small-scale processes require a highly spatially distributed and explicit modeling approach. However, detailed data for model development are often not available for large urban areas, hampering the model parameterization. In this paper we propose a methodology to parameterize a hydrological model to a large, ungauged urban area by maintaining at the same time a detailed surface discretization for direct parameter manipulation for LID simulation and a firm reliance on available data for model conceptualization. Catchment delineation was based on a high-resolution digital elevation model (DEM and model parameterization relied on a novel model regionalization approach. The impact of automated delineation and model regionalization on simulation results was evaluated for three monitored study catchments (5.87–12.59 ha. The simulated runoff peak was most sensitive to accurate catchment discretization and calibration, while both the runoff volume and the fit of the hydrograph were less affected.

  14. Circuity Characteristics of Urban Travel Based on GPS Data: A Case Study of Guangzhou

    Directory of Open Access Journals (Sweden)

    Xiaoshu Cao

    2017-11-01

    Full Text Available A longer, wider and more complicated change in the travel path is put forward to adapt to the rapidly increasing expansion of metropolises in the field of urban travel. Urban travel requires higher levels of sustainable urban transport. Therefore,this paper explores the circuity characteristics of urban travel and investigates the temporal relationship between time and travel circuity and the spatial relationship between distance and travel circuity to understand the efficiency of urban travel. Based on Guangzhou Taxi-GPS big data, travel circuity is considered in this paper to analyze the circuity spatial distribution and strength characteristics of urban travel in three types of metropolitan regions, including core areas, transition areas and fringe areas. Depending on the different attributes of the three types, the consistency and dissimilar characteristics of travel circuity and influencing factors of travel circuity in metropolises are discussed. The results are shown as follows: (1 by observing the temporal andspatial distribution of travel circuity, it can be found that peaks and troughs change with time, and travel circuity of transition areas is higher than other areas during the peak period. When travelling in these three regions, travel circuity spatial distribution is consistent, which is the core-periphery distribution. When travelling among these three regions, travel circuity spatial distribution is distinct; (2 by analyzing the relationship between time and distance of travel and travel circuity, it can be seen that the shorter the travel time or travel distance, the greater the travel circuity, resulting in a lower travel efficiency; (3 the influence of six factors, including population, road and public transportation, on travel circuity is significant. Whether it is the origin point or destination point, when its location is closer to the city center and the station density of grid is lower, the travel circuity is higher.

  15. A new methodology for modelling of health risk from urban flooding exemplified by cholera

    DEFF Research Database (Denmark)

    Mark, Ole; Jørgensen, Claus; Hammond, Michael

    2016-01-01

    outlines a novel methodology for linking dynamic urban flood modelling with quantitative microbial risk assessment (QMRA). This provides a unique possibility for understanding the interaction between urban flooding and health risk caused by direct human contact with the flood water and hence gives...... and mortality, especially during floods. At present, there are no software tools capable of combining hydrodynamic modelling and health risk analyses, and the links between urban flooding and the health risk for the population due to direct contact with the flood water are poorly understood. The present paper...... an option for reducing the burden of disease in the population by use of intelligent urban flood risk management. The model linking urban flooding and health risk is applied to Dhaka City in Bangladesh, where waterborne diseases including cholera are endemic. The application to Dhaka City is supported...

  16. High-Resolution Urban Greenery Mapping for Micro-Climate Modelling Based on 3d City Models

    Science.gov (United States)

    Hofierka, J.; Gallay, M.; Kaňuk, J.; Šupinský, J.; Šašak, J.

    2017-10-01

    Urban greenery has various positive micro-climate effects including mitigation of heat islands. The primary root of heat islands in cities is in absorption of solar radiation by the mass of building structures, roads and other solid materials. The absorbed heat is subsequently re-radiated into the surroundings and increases ambient temperatures. The vegetation can stop and absorb most of incoming solar radiation mostly via the photosynthesis and evapotranspiration process. However, vegetation in mild climate of Europe manifests considerable annual seasonality which can also contribute to the seasonal change in the cooling effect of the vegetation on the urban climate. Modern methods of high-resolution mapping and new generations of sensors have brought opportunity to record the dynamics of urban greenery in a high resolution in spatial, spectral, and temporal domains. In this paper, we use the case study of the city of Košice in Eastern Slovakia to demonstrate the methodology of 3D mapping and modelling the urban greenery during one vegetation season in 2016. The purpose of this monitoring is to capture 3D effects of urban greenery on spatial distribution of solar radiation in urban environment. Terrestrial laser scanning was conducted on four selected sites within Košice in ultra-high spatial resolution. The entire study area, which included these four smaller sites, comprised 4 km2 of the central part of the city was flown within a single airborne lidar and photogrammetric mission to capture the upper parts of buildings and vegetation. The acquired airborne data were used to generate a 3D city model and the time series of terrestrial lidar data were integrated with the 3D city model. The results show that the terrestrial and airborne laser scanning techniques can be effectively used to monitor seasonal changes in foliage of trees in order to assess the transmissivity of the canopy for microclimate modelling.

  17. A Culturally Responsive Practice Model for Urban Indian Child Welfare Services.

    Science.gov (United States)

    Mindell, Robert; Vidal de Haymes, Maria; Francisco, Dale

    2003-01-01

    Describes a collaboration among a university, a state child welfare agency, and a Native American community organization to develop a culturally driven practice model for urban, Native American child welfare. Identifies challenges and opportunities in addressing the needs of urban Native American communities. Concludes with principles for…

  18. Modeling the resilience of urban water supply using the capital portfolio approach

    Science.gov (United States)

    Krueger, E. H.; Klammler, H.; Borchardt, D.; Frank, K.; Jawitz, J. W.; Rao, P. S.

    2017-12-01

    The dynamics of global change challenge the resilience of cities in a multitude of ways, including pressures resulting from population and consumption changes, production patterns, climate and landuse change, as well as environmental hazards. Responses to these challenges aim to improve urban resilience, but lack an adequate understanding of 1) the elements and processes that lead to the resilience of coupled natural-human-engineered systems, 2) the complex dynamics emerging from the interaction of these elements, including the availability of natural resources, infrastructure, and social capital, which may lead to 3) unintended consequences resulting from management responses. We propose a new model that simulates the coupled dynamics of five types of capitals (water resources, infrastructure, finances, political capital /management, and social adaptive capacity) that are necessary for the provision of water supply to urban residents. We parameterize the model based on data for a case study city, which is limited by constraints in water availability, financial resources, and faced with degrading infrastructure, as well as population increase, which challenge the urban management institutions. Our model analyzes the stability of the coupled system, and produces time series of the capital dynamics to quantify its resilience as a result of the portfolio of capitals available to usher adaptive capacity and to secure water supply subjected to multiple recurring shocks. We apply our model to one real urban water supply system located in an arid environment, as well as a wide range of hypothetical case studies, which demonstrates its applicability to various types of cities, and its ability to quantify and compare water supply resilience. The analysis of a range of urban water systems provides valuable insights into guiding more sustainable responses for maintaining the resilience of urban water supply around the globe, by showing how unsustainable responses risk the

  19. Model architecture of intelligent data mining oriented urban transportation information

    Science.gov (United States)

    Yang, Bogang; Tao, Yingchun; Sui, Jianbo; Zhang, Feizhou

    2007-06-01

    Aiming at solving practical problems in urban traffic, the paper presents model architecture of intelligent data mining from hierarchical view. With artificial intelligent technologies used in the framework, the intelligent data mining technology improves, which is more suitable for the change of real-time road condition. It also provides efficient technology support for the urban transport information distribution, transmission and display.

  20. Development of urban water consumption models for the City of Los Angeles

    Science.gov (United States)

    Mini, C.; Hogue, T. S.; Pincetl, S.

    2011-12-01

    Population growth and rapid urbanization coupled with uncertain climate change are causing new challenges for meeting urban water needs. In arid and semi-arid regions, increasing drought periods and decreasing precipitation have led to water supply shortages and cities are struggling with trade-offs between the water needs of growing urban populations and the well-being of urban ecosystems. The goal of the current research is to build models that can represent urban water use patterns in semi-arid cities by identifying the determinants that control both total and outdoor residential water use over the Los Angeles urban domain. The initial database contains monthly water use records aggregated to the zip code level collected from the Los Angeles Department of Water and Power (LADWP) from 2000 to 2010. Residential water use was normalized per capita and was correlated with socio-demographic, economic, climatic and vegetation characteristics across the City for the 2000-2010 period. Results show that ethnicity, per capita income, and the average number of persons per household are linearly related to total water use per capita. Inter-annual differences in precipitation and implementation of conservation measures affect water use levels across the City. The high variability in water use patterns across the City also appears strongly influenced by income and education levels. The temporal analysis of vegetation indices in the studied neighborhoods shows little correlation between precipitation patterns and vegetation greenness. Urban vegetation appears well-watered, presenting the same greenness activity over the study period despite an overall decrease in water use across the City. We hypothesize that over-watering is occurring and that outdoor water use represents a significant part of the residential water budget in various regions of the City. A multiple regression model has been developed that integrates these fundamental controlling factors to simulate residential

  1. A model for radiological dose assessment in an urban environment

    International Nuclear Information System (INIS)

    Hwang, Won Tae; Kim, Eun Han; Jeong, Hyo Joon; Suh, Kyung Suk; Han, Moon Hee

    2007-01-01

    A model for radiological dose assessment in an urban environment, METRO-K has been developed. Characteristics of the model are as follows ; 1) mathematical structures are simple (i.e. simplified input parameters) and easy to understand due to get the results by analytical methods using experimental and empirical data, 2) complex urban environment can easily be made up using only 5 types of basic surfaces, 3) various remediation measures can be applied to different surfaces by evaluating the exposure doses contributing from each contamination surface. Exposure doses contributing from each contamination surface at a particular location of a receptor were evaluated using the data library of kerma values as a function of gamma energy and contamination surface. A kerma data library was prepared for 7 representative types of Korean urban building by extending those data given for 4 representative types of European urban buildings. Initial input data are daily radionuclide concentration in air and precipitation, and fraction of chemical type. Final outputs are absorbed dose rate in air contributing from the basic surfaces as a function of time following a radionuclide deposition, and exposure dose rate contributing from various surfaces constituting the urban environment at a particular location of a receptor. As the result of a contaminative scenario for an apartment built-up area, exposure dose rates show a distinct difference for surrounding environment as well as locations of a receptor

  2. iTree-Hydro: Snow hydrology update for the urban forest hydrology model

    Science.gov (United States)

    Yang Yang; Theodore A. Endreny; David J. Nowak

    2011-01-01

    This article presents snow hydrology updates made to iTree-Hydro, previously called the Urban Forest Effects—Hydrology model. iTree-Hydro Version 1 was a warm climate model developed by the USDA Forest Service to provide a process-based planning tool with robust water quantity and quality predictions given data limitations common to most urban areas. Cold climate...

  3. Urban flood risk warning under rapid urbanization.

    Science.gov (United States)

    Chen, Yangbo; Zhou, Haolan; Zhang, Hui; Du, Guoming; Zhou, Jinhui

    2015-05-01

    In the past decades, China has observed rapid urbanization, the nation's urban population reached 50% in 2000, and is still in steady increase. Rapid urbanization in China has an adverse impact on urban hydrological processes, particularly in increasing the urban flood risks and causing serious urban flooding losses. Urban flooding also increases health risks such as causing epidemic disease break out, polluting drinking water and damaging the living environment. In the highly urbanized area, non-engineering measurement is the main way for managing urban flood risk, such as flood risk warning. There is no mature method and pilot study for urban flood risk warning, the purpose of this study is to propose the urban flood risk warning method for the rapidly urbanized Chinese cities. This paper first presented an urban flood forecasting model, which produces urban flood inundation index for urban flood risk warning. The model has 5 modules. The drainage system and grid dividing module divides the whole city terrain into drainage systems according to its first-order river system, and delineates the drainage system into grids based on the spatial structure with irregular gridding technique; the precipitation assimilation module assimilates precipitation for every grids which is used as the model input, which could either be the radar based precipitation estimation or interpolated one from rain gauges; runoff production module classifies the surface into pervious and impervious surface, and employs different methods to calculate the runoff respectively; surface runoff routing module routes the surface runoff and determines the inundation index. The routing on surface grid is calculated according to the two dimensional shallow water unsteady flow algorithm, the routing on land channel and special channel is calculated according to the one dimensional unsteady flow algorithm. This paper then proposed the urban flood risk warning method that is called DPSIR model based

  4. EXPURT - a model for evaluating exposure from radioactive material deposited in the urban environment

    International Nuclear Information System (INIS)

    Crick, M.J.; Brown, J.

    1990-06-01

    This model, EXPURT (EXPosure from Urban Radionuclide Transfer), is described in detail. The model simulates the movement of activity deposited on various surfaces in the urban environment and, by taking into account the shielding properties of buildings and the habits of the population, evaluates the external doses to members of the population living in such urban environments, as a function of time after deposition. One of the other advantages of EXPURT over simpler models is that it can be used to assess the possible dose reductions that might be achieved by various decontamination techniques; for example, it can estimate the effectiveness of decontaminating roof surfaces alone in reducing exposure to individuals living in an urban environment. Sensitivity/uncertainty studies have been performed whereby those parameters contributing most to remaining uncertainty in the model's predictions of dose and dose rates were identified. Predictions of the EXPURT model were compared with those from a simpler external dose model in use at NRPB. (author)

  5. Quantitative Analysis of Intra Urban Growth Modeling using socio economic agents by combining cellular automata model with agent based model

    Science.gov (United States)

    Singh, V. K.; Jha, A. K.; Gupta, K.; Srivastav, S. K.

    2017-12-01

    Recent studies indicate that there is a significant improvement in the urban land use dynamics through modeling at finer spatial resolutions. Geo-computational models such as cellular automata and agent based model have given evident proof regarding the quantification of the urban growth pattern with urban boundary. In recent studies, socio- economic factors such as demography, education rate, household density, parcel price of the current year, distance to road, school, hospital, commercial centers and police station are considered to the major factors influencing the Land Use Land Cover (LULC) pattern of the city. These factors have unidirectional approach to land use pattern which makes it difficult to analyze the spatial aspects of model results both quantitatively and qualitatively. In this study, cellular automata model is combined with generic model known as Agent Based Model to evaluate the impact of socio economic factors on land use pattern. For this purpose, Dehradun an Indian city is selected as a case study. Socio economic factors were collected from field survey, Census of India, Directorate of economic census, Uttarakhand, India. A 3X3 simulating window is used to consider the impact on LULC. Cellular automata model results are examined for the identification of hot spot areas within the urban area and agent based model will be using logistic based regression approach where it will identify the correlation between each factor on LULC and classify the available area into low density, medium density, high density residential or commercial area. In the modeling phase, transition rule, neighborhood effect, cell change factors are used to improve the representation of built-up classes. Significant improvement is observed in the built-up classes from 84 % to 89 %. However after incorporating agent based model with cellular automata model the accuracy improved from 89 % to 94 % in 3 classes of urban i.e. low density, medium density and commercial classes

  6. Urban Growth Modelling with Artificial Neural Network and Logistic Regression. Case Study: Sanandaj City, Iran

    Directory of Open Access Journals (Sweden)

    SASSAN MOHAMMADY

    2013-01-01

    Full Text Available Cities have shown remarkable growth due to attraction, economic, social and facilities centralization in the past few decades. Population and urban expansion especially in developing countries, led to lack of resources, land use change from appropriate agricultural land to urban land use and marginalization. Under these circumstances, land use activity is a major issue and challenge for town and country planners. Different approaches have been attempted in urban expansion modelling. Artificial Neural network (ANN models are among knowledge-based models which have been used for urban growth modelling. ANNs are powerful tools that use a machine learning approach to quantify and model complex behaviour and patterns. In this research, ANN and logistic regression have been employed for interpreting urban growth modelling. Our case study is Sanandaj city and we used Landsat TM and ETM+ imageries acquired at 2000 and 2006. The dataset used includes distance to main roads, distance to the residence region, elevation, slope, and distance to green space. Percent Area Match (PAM obtained from modelling of these changes with ANN is equal to 90.47% and the accuracy achieved for urban growth modelling with Logistic Regression (LR is equal to 88.91%. Percent Correct Match (PCM and Figure of Merit for ANN method were 91.33% and 59.07% and then for LR were 90.84% and 57.07%, respectively.

  7. COMMUNICATION MODEL IN SOCIALIZING OF URBAN FARMING “KAMPUNG BERKEBUN” INNOVATION PROGRAM IN BANDUNG CITY (MODEL KOMUNIKASI DALAM MEMASYARAKATKAN PROGRAM INOVASI URBAN FARMING “KAMPUNG BERKEBUN” DI KOTA BANDUNG PROPINSI JAWA BARAT

    Directory of Open Access Journals (Sweden)

    Henny Sri Mulyani R

    2016-10-01

    Full Text Available An innovation promoted by the government of the city of Bandung in 2014 that urban gardening activities by utilizing their yards, vacant land, alley, dak  and the other, better known as Urban Farming. This activity was intended for residents of the city of Bandung with the hope of meeting the food needs of the household and supporting urban green open space. The purpose of this study was to determine the model of communication used by the Department of Agriculture and Food Security in the dissemination of innovation Urban Farming "Kampung Berkebun" in Bandung. This was accomplished through qualitative description methods of data collection and analysis using some observations, personal interviews and textual analysis. The results showed that the program of promoting Urban Farming "Kampung Berkebun" consists of two activities, namely the first event, to be disseminated to the subdistrict and village heads as the city of Bandung which is held at the Department of Agriculture and Food Security in Bandung, and the second activity is to provide training to the residents in the village location. Bandung has 34 districts and 151 villages. Training was conducted at each site include a village with a maximum of 50 people of the village residents. Deployment of innovative communication model Urban Farming "Kampung Berkebun" in the form of a model that is both mechanistic and interactional namely communication model David K Berlo (1960 and Schramm communication model (1954.   Sebuah inovasi  dimasyarakatkan oleh pemerintahan Kota Bandung mulai tahun 2014 yaitu kegiatan berkebun diperkotaan dengan memanfaatkan lahan pekarangan, lahan tidur, gang, dak  dan yang lainnya   lebih dikenal dengan sebutan  Urban Farming. Kegiatan ini diperuntukan bagi   warga Kota Bandung dengan harapan dapat memenuhi kebutuhan pangan dalam skala rumah tangga dan menunjang ruang terbuka hijau perkotaan. Tujuan penelitian ini adalah untuk mengetahui model komunikasi yang

  8. Analysis and Modeling of Urban Land Cover Change in Setúbal and Sesimbra, Portugal

    Directory of Open Access Journals (Sweden)

    Yikalo H. Araya

    2010-06-01

    Full Text Available The expansion of cities entails the abandonment of forest and agricultural lands, and these lands’ conversion into urban areas, which results in substantial impacts on ecosystems. Monitoring these changes and planning urban development can be successfully achieved using multitemporal remotely sensed data, spatial metrics, and modeling. In this paper, urban land use change analysis and modeling was carried out for the Concelhos of Setúbal and Sesimbra in Portugal. An existing land cover map for the year 1990, together with two derived land cover maps from multispectral satellite images for the years 2000 and 2006, were utilized using an object-oriented classification approach. Classification accuracy assessment revealed satisfactory results that fulfilled minimum standard accuracy levels. Urban land use dynamics, in terms of both patterns and quantities, were studied using selected landscape metrics and the Shannon Entropy index. Results show that urban areas increased by 91.11% between 1990 and 2006. In contrast, the change was only 6.34% between 2000 and 2006. The entropy value was 0.73 for both municipalities in 1990, indicating a high rate of urban sprawl in the area. In 2006, this value, for both Sesimbra and Setúbal, reached almost 0.90. This is demonstrative of a tendency toward intensive urban sprawl. Urban land use change for the year 2020 was modeled using a Cellular Automata based approach. The predictive power of the model was successfully validated using Kappa variations. Projected land cover changes show a growing tendency in urban land use, which might threaten areas that are currently reserved for natural parks and agricultural lands.

  9. Partitioning the impacts of spatial and climatological rainfall variability in urban drainage modeling

    Science.gov (United States)

    Peleg, Nadav; Blumensaat, Frank; Molnar, Peter; Fatichi, Simone; Burlando, Paolo

    2017-03-01

    The performance of urban drainage systems is typically examined using hydrological and hydrodynamic models where rainfall input is uniformly distributed, i.e., derived from a single or very few rain gauges. When models are fed with a single uniformly distributed rainfall realization, the response of the urban drainage system to the rainfall variability remains unexplored. The goal of this study was to understand how climate variability and spatial rainfall variability, jointly or individually considered, affect the response of a calibrated hydrodynamic urban drainage model. A stochastic spatially distributed rainfall generator (STREAP - Space-Time Realizations of Areal Precipitation) was used to simulate many realizations of rainfall for a 30-year period, accounting for both climate variability and spatial rainfall variability. The generated rainfall ensemble was used as input into a calibrated hydrodynamic model (EPA SWMM - the US EPA's Storm Water Management Model) to simulate surface runoff and channel flow in a small urban catchment in the city of Lucerne, Switzerland. The variability of peak flows in response to rainfall of different return periods was evaluated at three different locations in the urban drainage network and partitioned among its sources. The main contribution to the total flow variability was found to originate from the natural climate variability (on average over 74 %). In addition, the relative contribution of the spatial rainfall variability to the total flow variability was found to increase with longer return periods. This suggests that while the use of spatially distributed rainfall data can supply valuable information for sewer network design (typically based on rainfall with return periods from 5 to 15 years), there is a more pronounced relevance when conducting flood risk assessments for larger return periods. The results show the importance of using multiple distributed rainfall realizations in urban hydrology studies to capture the

  10. Importance-Performance Analysis of Taxi Service Quality%客运出租汽车服务质量的重要度-绩效分析

    Institute of Scientific and Technical Information of China (English)

    姚志刚

    2011-01-01

    为了明确客运出租汽车服务质量管理的重点,根据SERVPERF模型将客运出租汽车服务质量划分为22个构成要素.以杭州市为例进行乘客调查,采用区间估计法计算各服务质量构成要素的重要度和绩效均值及其置信区间,建立服务质量的重要度-绩效分析四象限矩阵,在95%置信水平下从12个构成要素中获得客运出租汽车服务质量重点改善的5方面内容.结果表明,客运出租汽车服务质量管理应从提高车辆档次、外观和加强安全设施配置转向改善车内卫生、治理驾驶员拒载绕道和规范驾驶员行为;采用区间估计修正传统重要度-绩效分析法,可减少问卷调查的统计误差,使客运出租汽车服务质量评价结果更加可信.%To identify the key points of taxi service management, a SERVPERF instrument including 22 items is proposed to measure the taxi service quality. Scales of importance and performance of all items are obtained in a passenger survey in Hangzhou, China. Confidence intervals of means of those importance and performance are calculated with interval estimation and a four-quadrant matrix of importance-performance analysis is conducted. Five items of the priority task for taxi service management are obtained from 12 items at the 95% confidence level. The present study reveals that resources used for improving vehicle facilities and safety equipments should be reduced and be applied for vehicle interior cleanliness, driver' s refusal and detour, driver's rude behaviors and service consciousness. The result indicates that the revised importance-performance analysis with interval estimation is a reliable approach for measuring key factors of taxi service management.

  11. Investigation of a coupling model of coordination between urbanization and the environment.

    Science.gov (United States)

    Li, Yangfan; Li, Yi; Zhou, Yan; Shi, Yalou; Zhu, Xiaodong

    2012-05-15

    China's coastal cities are experiencing rapid urbanization, which has resulted in many challenges. This paper presents a comprehensive index system for assessment of the level of urbanization based on four aspects: demographic urbanization, economic urbanization, social urbanization and spatial urbanization. The developed index system also characterizes the environment based on three factors: environmental pressure, environmental level and environmental control. Furthermore, a coupling coordination degree model (CCDM) focusing on the degree of coordination between urbanization and the environment was established using panel data collected from 2000 to 2008 for Lianyungang, China. The results showed that: (1) the dynamic of coordination between urbanization and the environment showed a U-shaped curve, and both sub-systems evolved into a superior balance during rapid urbanization; (2) social urbanization and environmental control make the greatest contribution to the coupling system, indicating that they are the critical factors to consider when adjusting coordination development during decision-making; and (3) the two parameters (α-urbanization, β-environment) that have been widely used in previous studies had less of an effect on the coupling coordinated system than the other factors considered herein. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Indirect Damage of Urban Flooding: Investigation of Flood-Induced Traffic Congestion Using Dynamic Modeling

    Directory of Open Access Journals (Sweden)

    Jingxuan Zhu

    2018-05-01

    Full Text Available In many countries, industrialization has led to rapid urbanization. Increased frequency of urban flooding is one consequence of the expansion of urban areas which can seriously affect the productivity and livelihoods of urban residents. Therefore, it is of vital importance to study the effects of rainfall and urban flooding on traffic congestion and driver behavior. In this study, a comprehensive method to analyze the influence of urban flooding on traffic congestion was developed. First, a flood simulation was conducted to predict the spatiotemporal distribution of flooding based on Storm Water Management Model (SWMM and TELAMAC-2D. Second, an agent-based model (ABM was used to simulate driver behavior during a period of urban flooding, and a car-following model was established. Finally, in order to study the mechanisms behind how urban flooding affects traffic congestion, the impact of flooding on urban traffic was investigated based on a case study of the urban area of Lishui, China, covering an area of 4.4 km2. It was found that for most events, two-hour rainfall has a certain impact on traffic congestion over a five-hour period, with the greatest impact during the hour following the cessation of the rain. Furthermore, the effects of rainfall with 10- and 20-year return periods were found to be similar and small, whereas the effects with a 50-year return period were obvious. Based on a combined analysis of hydrology and transportation, the proposed methods and conclusions could help to reduce traffic congestion during flood seasons, to facilitate early warning and risk management of urban flooding, and to assist users in making informed decisions regarding travel.

  13. A Two-Stage Queue Model to Optimize Layout of Urban Drainage System considering Extreme Rainstorms

    OpenAIRE

    He, Xinhua; Hu, Wenfa

    2017-01-01

    Extreme rainstorm is a main factor to cause urban floods when urban drainage system cannot discharge stormwater successfully. This paper investigates distribution feature of rainstorms and draining process of urban drainage systems and uses a two-stage single-counter queue method M/M/1→M/D/1 to model urban drainage system. The model emphasizes randomness of extreme rainstorms, fuzziness of draining process, and construction and operation cost of drainage system. Its two objectives are total c...

  14. A Model for Urban Environment and Resource Planning Based on Green GDP Accounting System

    Directory of Open Access Journals (Sweden)

    Linyu Xu

    2013-01-01

    Full Text Available The urban environment and resources are currently on course that is unsustainable in the long run due to excessive human pursuit of economic goals. Thus, it is very important to develop a model to analyse the relationship between urban economic development and environmental resource protection during the process of rapid urbanisation. This paper proposed a model to identify the key factors in urban environment and resource regulation based on a green GDP accounting system, which consisted of four parts: economy, society, resource, and environment. In this model, the analytic hierarchy process (AHP method and a modified Pearl curve model were combined to allow for dynamic evaluation, with higher green GDP value as the planning target. The model was applied to the environmental and resource planning problem of Wuyishan City, and the results showed that energy use was a key factor that influenced the urban environment and resource development. Biodiversity and air quality were the most sensitive factors that influenced the value of green GDP in the city. According to the analysis, the urban environment and resource planning could be improved for promoting sustainable development in Wuyishan City.

  15. Urban forests for sustainable urban development

    Science.gov (United States)

    Sundara, Denny M.; Hartono, Djoko M.; Suganda, Emirhadi; Haeruman, S. Herman J.

    2017-11-01

    This paper explores the development of the urban forest in East Jakarta. By 2030 Jakarta area has a target of 30% green area covering 19,845 hectares, including urban forest covering an area of 4,631 hectares. In 2015, the city forest is only 646 hectares, while the city requires 3,985 hectares of new land Urban forest growth from year to year showed a marked decrease with increasing land area awoke to commercial functions, environmental conditions encourage the development of the city to become unsustainable. This research aims to support sustainable urban development and ecological balance through the revitalization of green areas and urban development. Analytical methods for urban forest area is calculated based on the amount of CO2 that comes from people, vehicles, and industrial. Urban spatial analysis based on satellite image data, using a GIS program is an analysis tool to determine the distribution and growth patterns of green areas. This paper uses a dynamic system model to simulate the conditions of the region against intervention to be performed on potential areas for development of urban forests. The result is a model urban forest area is integrated with a social and economic function to encourage the development of sustainable cities.

  16. RANS modeling of scalar dispersion from localized sources within a simplified urban-area model

    Science.gov (United States)

    Rossi, Riccardo; Capra, Stefano; Iaccarino, Gianluca

    2011-11-01

    The dispersion of a passive scalar downstream a localized source within a simplified urban-like geometry is examined by means of RANS scalar flux models. The computations are conducted under conditions of neutral stability and for three different incoming wind directions (0°, 45°, 90°) at a roughness Reynolds number of Ret = 391. A Reynolds stress transport model is used to close the flow governing equations whereas both the standard eddy-diffusivity closure and algebraic flux models are employed to close the transport equation for the passive scalar. The comparison with a DNS database shows improved reliability from algebraic scalar flux models towards predicting both the mean concentration and the plume structure. Since algebraic flux models do not increase substantially the computational effort, the results indicate that the use of tensorial-diffusivity can be promising tool for dispersion simulations for the urban environment.

  17. Hyper-resolution urban flood modeling using high-resolution radar precipitation and LiDAR data

    Science.gov (United States)

    Noh, S. J.; Lee, S.; Lee, J.; Seo, D. J.

    2016-12-01

    Floods occur most frequently among all natural hazards, often causing widespread economic damage and loss of human lives. In particular, urban flooding is becoming increasingly costly and difficult to manage with a greater concentration of population and assets in urban centers. Despite of known benefits for accurate representation of small scale features and flow interaction among different flow domains, which have significant impact on flood propagation, high-resolution modeling has not been fully utilized due to expensive computation and various uncertainties from model structure, input and parameters. In this study, we assess the potential of hyper-resolution hydrologic-hydraulic modeling using high-resolution radar precipitation and LiDAR data for improved urban flood prediction and hazard mapping. We describe a hyper-resolution 1D-2D coupled urban flood model for pipe and surface flows and evaluate the accuracy of the street-level inundation information produced. For detailed geometric representation of urban areas and for computational efficiency, we use 1 m-resolution topographical data, processed from LiDAR measurements, in conjunction with adaptive mesh refinement. For street-level simulation in large urban areas at grid sizes of 1 to 10 m, a hybrid parallel computing scheme using MPI and openMP is also implemented in a high-performance computing system. The modeling approach developed is applied for the Johnson Creek Catchment ( 40 km2), which makes up the Arlington Urban Hydroinformatics Testbed. In addition, discussion will be given on availability of hyper-resolution simulation archive for improved real-time flood mapping.

  18. Nested 1D-2D approach for urban surface flood modeling

    Science.gov (United States)

    Murla, Damian; Willems, Patrick

    2015-04-01

    Floods in urban areas as a consequence of sewer capacity exceedance receive increased attention because of trends in urbanization (increased population density and impermeability of the surface) and climate change. Despite the strong recent developments in numerical modeling of water systems, urban surface flood modeling is still a major challenge. Whereas very advanced and accurate flood modeling systems are in place and operation by many river authorities in support of flood management along rivers, this is not yet the case in urban water management. Reasons include the small scale of the urban inundation processes, the need to have very high resolution topographical information available, and the huge computational demands. Urban drainage related inundation modeling requires a 1D full hydrodynamic model of the sewer network to be coupled with a 2D surface flood model. To reduce the computational times, 0D (flood cones), 1D/quasi-2D surface flood modeling approaches have been developed and applied in some case studies. In this research, a nested 1D/2D hydraulic model has been developed for an urban catchment at the city of Gent (Belgium), linking the underground sewer (minor system) with the overland surface (major system). For the overland surface flood modelling, comparison was made of 0D, 1D/quasi-2D and full 2D approaches. The approaches are advanced by considering nested 1D-2D approaches, including infiltration in the green city areas, and allowing the effects of surface storm water storage to be simulated. An optimal nested combination of three different mesh resolutions was identified; based on a compromise between precision and simulation time for further real-time flood forecasting, warning and control applications. Main streets as mesh zones together with buildings as void regions constitute one of these mesh resolution (3.75m2 - 15m2); they have been included since they channel most of the flood water from the manholes and they improve the accuracy of

  19. Study of thermal environment in Jingjintang urban agglomeration based on WRF model and Landsat data

    International Nuclear Information System (INIS)

    Huang, Q N; Cao, Z Q; Guo, H D; Xi, X H; Li, X W

    2014-01-01

    In recent decades, unprecedented urban expansion has taken place in developing countries resulting in the emergence of megacities or urban agglomeration. It has been highly concerned by many countries about a variety of urban environmental issues such as greenhouse gas emissions and urban heat island phenomenon associated with urbanization. Generally, thermal environment is monitored by remote sensing satellite data. This method is usually limited by weather and repeated cycle. Another approach is relied on numerical simulation based on models. In the study, these two means are combined to study the thermal environment of Jingjintang urban agglomeration. The high temperature processes of the study area in 2009 and 1990s are simulated by using WRF (the Weather Research and Forecasting Model) coupled with UCM (Urban Canopy Model) and the urban impervious surface estimated from Landsat-5 TM data using support vector machine. Results show that the trend of simulated air temperature (2 meter) is in accord with observed air temperature. Moreover, it indicates the differences of air temperature and Land Surface Temperature caused by the urbanization efficiently. The UHI effect at night is stronger than that in the day. The maximum difference of LST reaches to 8–10°C for new build-up area at night. The method provided in this research can be used to analyze impacts on urban thermal environment caused by urbanization and it also provides means on thermal environment monitoring and prediction which will benefit the coping capacity of extreme event

  20. Model and Empirical Study on Several Urban Public Transport Networks in China

    Science.gov (United States)

    Ding, Yimin; Ding, Zhuo

    2012-07-01

    In this paper, we present the empirical investigation results on the urban public transport networks (PTNs) and propose a model to understand the results obtained. We investigate some urban public traffic networks in China, which are the urban public traffic networks of Beijing, Guangzhou, Wuhan and etc. The empirical results on the big cities show that the accumulative act-degree distributions of PTNs take neither power function forms, nor exponential function forms, but they are described by a shifted power function, and the accumulative act-degree distributions of PTNs in medium-sized or small cities follow the same law. In the end, we propose a model to show a possible evolutionary mechanism for the emergence of such network. The analytic results obtained from this model are in good agreement with the empirical results.

  1. Fate modeling of mercury species and fluxes estimation in an urban river

    International Nuclear Information System (INIS)

    Tong, Yindong; Zhang, Wei; Chen, Cen; Chen, Long; Wang, Wentao; Hu, Xindi; Wang, Huanhuan; Hu, Dan; Ou, Langbo; Wang, Xuejun; Wang, Qiguang

    2014-01-01

    The fate and transfer of mercury in urban river is an important environmental concern. In this study, QWASI (Quantitative Water–Air–Sediment Interaction) model was selected to estimate the levels of total mercury and three mercury species in water and sediment, and was used to quantify the fluxes of mercury at water/air and sediment/water interfaces of an urban river. The predicted mercury levels in water and sediments were closed to the measured values. Water inflow, re-suspension of sediment and diffusion from sediment to water are major input sources of mercury in water. The net mercury transfer flux from water to air was 0.16 ng/(m 2 h). At the sediment/water interface, a net total mercury transfer of 1.32 ng/(m 2 h) from water to sediment was seen. In addition to the existing dynamic flux chambers measurement, this model method could provide a new perspective to identify the distribution and transfer of mercury in the urban river. -- Highlights: • QWASI could be a good tool to quantify transfer and fate of mercury in environment. • Distribution and flux of mercury species in an urban river was modeled. • Mercury in water mainly came from water inflow, sediment re-suspension and diffusion. • Net mercury transfer from water to air and sediment were 0.16 and 1.32 ng/(m 2 h). -- Quantitative Water–Air–Sediment Interaction model was used to quantify the transfer and fate of mercury in an urban river

  2. Model of urban poverty alleviation through the development of entrepreneurial spirit and business competence

    Science.gov (United States)

    Aryaningsih, NN; Irianto, Kt; Marsa Arsana, Md; Juli Suarbawa, Kt

    2018-01-01

    The rapid increased of urban population can not be controlled by the city government. This will have an impact on the emergence of new poverty in urban areas, due to inadequate of the job opportunities and skills. Government programs for poverty alleviation can reduce some rural poverty, but have not been able to overcome poverty in urban areas. The diversity of urban issues and needs is greater than in rural areas. Therefore, it is necessary to conduct the research with the aim to build urban poverty reduction model through the development of entrepreneurship spirit and business competence. This research was conducted by investigation method, and questionnaire. Questionnaires are arranged with rating scale measurements. The validity and reliability of the questionnaire were tested by factor analysis. Model construction is constructed from various informant analyzes and descriptive statistical analysis. The results show that poverty alleviation model is very effective done by developing spirit of entrepreneurship and business competence.

  3. Regional/Urban Air Quality Modeling Assessment over China Using the Models-3/CMAQ System

    Science.gov (United States)

    Fu, J. S.; Jang, C. C.; Streets, D. G.; Li, Z.; Wang, L.; Zhang, Q.; Woo, J.; Wang, B.

    2004-12-01

    China is the world's most populous country with a fast growing economy that surges in energy comsumption. It has become the second largest energy consumer after the United States although the per capita level is much lower than those found in developed or developing countries. Air pollution has become one of the most important problems of megacities such as Beijing and Shanghai and has serious impacts on public health, causes urban and regional haze. The Models-3/CMAQ modeling application that has been conducted to simulate multi-pollutants in China is presented. The modeling domains cover East Asia (36-kmx36-km) including Japan, South Korea, Korea DPR, Indonesia, Thailand, India and Mongolia, East China (12-kmx12-km) and Beijing/Tianjing, Shanghai (4-kmx4-km). For this study, the Asian emission inventory based on the emission estimates of the year 2000 that supported the NASA TRACE-P program is used. However, the TRACE-P emission inventory was developed for a different purpose such as global modeling. TRACE-P emission inventory may not be practical in urban area. There is no China national emission inventory available. Therefore, TRACE-P emission inventory is used on the East Asia and East China domains. The 8 districts of Beijing and Shanghai local emissions inventory are used to replace TRACE-P in 4-km domains. The meteorological data for the Models-3/CMAQ run are extracted from MM5. The model simulation is performed during the period January 1-20 and July 1-20, 2001 that presented the winter and summer time for China areas. The preliminary model results are shown O3 concentrations are in the range of 80 -120 ppb in the urban area. Lower urban O3 concentrations are shown in Beijing areas, possibly due to underestimation of urban man-made VOC emissions in the TRACE-P inventory and local inventory. High PM2.5 (70ug/m3 in summer and 150ug/m3 in winter) were simulated over metropolitan & downwind areas with significant secondary constituents. More comprehensive

  4. Reconstruction and simplification of urban scene models based on oblique images

    Science.gov (United States)

    Liu, J.; Guo, B.

    2014-08-01

    We describe a multi-view stereo reconstruction and simplification algorithms for urban scene models based on oblique images. The complexity, diversity, and density within the urban scene, it increases the difficulty to build the city models using the oblique images. But there are a lot of flat surfaces existing in the urban scene. One of our key contributions is that a dense matching algorithm based on Self-Adaptive Patch in view of the urban scene is proposed. The basic idea of matching propagating based on Self-Adaptive Patch is to build patches centred by seed points which are already matched. The extent and shape of the patches can adapt to the objects of urban scene automatically: when the surface is flat, the extent of the patch would become bigger; while the surface is very rough, the extent of the patch would become smaller. The other contribution is that the mesh generated by Graph Cuts is 2-manifold surface satisfied the half edge data structure. It is solved by clustering and re-marking tetrahedrons in s-t graph. The purpose of getting 2- manifold surface is to simply the mesh by edge collapse algorithm which can preserve and stand out the features of buildings.

  5. Real time adjustment of slow changing flow components in distributed urban runoff models

    DEFF Research Database (Denmark)

    Borup, Morten; Grum, M.; Mikkelsen, Peter Steen

    2011-01-01

    In many urban runoff systems infiltrating water contributes with a substantial part of the total inflow and therefore most urban runoff modelling packages include hydrological models for simulating the infiltrating inflow. This paper presents a method for deterministic updating of the hydrological...... improvements for regular simulations as well as up to 10 hour forecasts. The updating method reduces the impact of non-representative precipitation estimates as well as model structural errors and leads to better overall modelling results....

  6. Data-driven modeling of solar-powered urban microgrids.

    Science.gov (United States)

    Halu, Arda; Scala, Antonio; Khiyami, Abdulaziz; González, Marta C

    2016-01-01

    Distributed generation takes center stage in today's rapidly changing energy landscape. Particularly, locally matching demand and generation in the form of microgrids is becoming a promising alternative to the central distribution paradigm. Infrastructure networks have long been a major focus of complex networks research with their spatial considerations. We present a systemic study of solar-powered microgrids in the urban context, obeying real hourly consumption patterns and spatial constraints of the city. We propose a microgrid model and study its citywide implementation, identifying the self-sufficiency and temporal properties of microgrids. Using a simple optimization scheme, we find microgrid configurations that result in increased resilience under cost constraints. We characterize load-related failures solving power flows in the networks, and we show the robustness behavior of urban microgrids with respect to optimization using percolation methods. Our findings hint at the existence of an optimal balance between cost and robustness in urban microgrids.

  7. A Practical Review of Integrated Urban Water Models: Applications as Decision Support Tools and Beyond

    Science.gov (United States)

    Mosleh, L.; Negahban-Azar, M.

    2017-12-01

    The integrated urban water management has become a necessity due to the high rate of urbanization, water scarcity, and climate variability. Climate and demographic changes, shifting the social attitude toward the water usage, and insufficiencies in system resilience increase the pressure on the water resources. Alongside with the water management, modeling urban water systems have progressed from traditional view to comprise alternatives such as decentralized water and wastewater systems, fit-for-purpose practice, graywater/rainwater reuse, and green infrastructure. While there are review papers available focusing on the technical part of the models, they seem to be more beneficial for model developers. Some of the models analyze a number of scenarios considering factors such as climate change and demography and their future impacts. However, others only focus on quality and quantity of water in a supply/demand approach. For example, optimizing the size of water or waste water store, characterizing the supply and quantity of urban stormwater and waste water, and link source of water to demand. A detailed and practical comparison of such models has become a necessity for the practitioner and policy makers. This research compares more than 7 most commonly used integrated urban water cycle models and critically reviews their capabilities, input requirements, output and their applications. The output of such detailed comparison will help the policy makers for the decision process in the built environment to compare and choose the best models that meet their goals. The results of this research show that we need a transition from developing/using integrated water cycle models to integrated system models which incorporate urban water infrastructures and ecological and economic factors. Such models can help decision makers to reflect other important criteria but with the focus on urban water management. The research also showed that there is a need in exploring

  8. Key Parameters for Urban Heat Island Assessment in A Mediterranean Context: A Sensitivity Analysis Using the Urban Weather Generator Model

    Science.gov (United States)

    Salvati, Agnese; Palme, Massimo; Inostroza, Luis

    2017-10-01

    Although Urban Heat Island (UHI) is a fundamental effect modifying the urban climate, being widely studied, the relative weight of the parameters involved in its generation is still not clear. This paper investigates the hierarchy of importance of eight parameters responsible for UHI intensity in the Mediterranean context. Sensitivity analyses have been carried out using the Urban Weather Generator model, considering the range of variability of: 1) city radius, 2) urban morphology, 3) tree coverage, 4) anthropogenic heat from vehicles, 5) building’s cooling set point, 6) heat released to canyon from HVAC systems, 7) wall construction properties and 8) albedo of vertical and horizontal surfaces. Results show a clear hierarchy of significance among the considered parameters; the urban morphology is the most important variable, causing a relative change up to 120% of the annual average UHI intensity in the Mediterranean context. The impact of anthropogenic sources of heat such as cooling systems and vehicles is also significant. These results suggest that urban morphology parameters can be used as descriptors of the climatic performance of different urban areas, easing the work of urban planners and designers in understanding a complex physical phenomenon, such as the UHI.

  9. An analysis of urban collisions using an artificial intelligence model.

    Science.gov (United States)

    Mussone, L; Ferrari, A; Oneta, M

    1999-11-01

    Traditional studies on road accidents estimate the effect of variables (such as vehicular flows, road geometry, vehicular characteristics), and the calculation of the number of accidents. A descriptive statistical analysis of the accidents (those used in the model) over the period 1992-1995 is proposed. The paper describes an alternative method based on the use of artificial neural networks (ANN) in order to work out a model that relates to the analysis of vehicular accidents in Milan. The degree of danger of urban intersections using different scenarios is quantified by the ANN model. Methodology is the first result, which allows us to tackle the modelling of urban vehicular accidents by the innovative use of ANN. Other results deal with model outputs: intersection complexity may determine a higher accident index depending on the regulation of intersection. The highest index for running over of pedestrian occurs at non-signalised intersections at night-time.

  10. A competitive carbon emissions scheme with hybrid fiscal incentives: The evidence from a taxi industry

    International Nuclear Information System (INIS)

    Liu, Yang; Han, Liyan; Yin, Ziqiao; Luo, Kongyi

    2017-01-01

    As two major approaches to reduce carbon emissions, command-and-control instruments and market-based carbon trading systems have their own weaknesses. Our paper first proposes a type of endogenous equilibrium methodology to dynamically derive the industrial carbon emissions standards. At the equilibrium, the sum of all carbon assets and liabilities is zero in the considered industry. Moreover, the standards fall over time with low-carbon technological advance. Most importantly, combining Pigou's and Coase's ideas, we construct a fiscal instrument accounting for both carbon taxes and allowances based on the dynamically improved emissions standards and carbon trading prices. This “No revenue for government” method implements a self-operated ecology for carbon trading market. Finally, considering the “Waterloo” recession of carbon prices, we introduce an adjustment factor into the model, which generates a negative-feedback mechanism with carbon prices. To support our idea, we present the application to Beijing taxi industry in detail and raise relative policy implications based on the evidence. - Highlights: • Dynamic endogenous equilibrium standards for carbon emissions. • A public policy oriented market mechanism combining command-and-control instruments and carbon trading. • Hybrid incentives to emission reduction combining carbon taxes and allowances. • The adjustment coefficient generating a negative feedback mechanism with carbon prices.

  11. A new methodology for dynamic modelling of health risks arising from wastewater influenced urban flooding

    Science.gov (United States)

    Jørgensen, Claus; Mark, Ole; Djordjevic, Slobodan; Hammond, Michael; Khan, David M.; Erichsen, Anders; Dorrit Enevoldsen, Ann; Heinicke, Gerald; Helwigh, Birgitte

    2015-04-01

    Indroduction Urban flooding due to rainfall exceeding the design capacity of drainage systems is a global problem and it has significant economic and social consequences. While the cost of the direct flood damages of urban flooding is well understood, the indirect damages, like the water borne diseases is in general still poorly understood. Climate changes are expected to increase the frequency of urban flooding in many countries which is likely to increase water borne diseases. Diarrheal diseases are most prevalent in developing countries, where poor sanitation, poor drinking water and poor surface water quality causes a high disease burden and mortality, especially during floods. The level of water borne diarrhea in countries with well-developed water and waste water infrastructure has been reduced to an acceptable level, and the population in general do not consider waste water as being a health risk. Hence, exposure to wastewater influenced urban flood water still has the potential to cause transmission of diarrheal diseases. When managing urban flooding and planning urban climate change adaptations, health risks are rarely taken into consideration. This paper outlines a novel methodology for linking dynamic urban flood modelling with Quantitative Microbial Risk Assessment (QMRA). This provides a unique possibility for understanding the interaction between urban flooding and the health risks caused by direct human contact with flood water and provides an option for reducing the burden of disease in the population through the use of intelligent urban flood risk management. Methodology We have linked hydrodynamic urban flood modelling with quantitative microbial risk assessment (QMRA) to determine the risk of infection caused by exposure to wastewater influenced urban flood water. The deterministic model MIKE Flood, which integrates the sewer network model in MIKE Urban and the 2D surface model MIKE21, was used to calculate the concentration of pathogens in the

  12. Global distribution of urban parameters derived from high-resolution global datasets for weather modelling

    Science.gov (United States)

    Kawano, N.; Varquez, A. C. G.; Dong, Y.; Kanda, M.

    2016-12-01

    Numerical model such as Weather Research and Forecasting model coupled with single-layer Urban Canopy Model (WRF-UCM) is one of the powerful tools to investigate urban heat island. Urban parameters such as average building height (Have), plain area index (λp) and frontal area index (λf), are necessary inputs for the model. In general, these parameters are uniformly assumed in WRF-UCM but this leads to unrealistic urban representation. Distributed urban parameters can also be incorporated into WRF-UCM to consider a detail urban effect. The problem is that distributed building information is not readily available for most megacities especially in developing countries. Furthermore, acquiring real building parameters often require huge amount of time and money. In this study, we investigated the potential of using globally available satellite-captured datasets for the estimation of the parameters, Have, λp, and λf. Global datasets comprised of high spatial resolution population dataset (LandScan by Oak Ridge National Laboratory), nighttime lights (NOAA), and vegetation fraction (NASA). True samples of Have, λp, and λf were acquired from actual building footprints from satellite images and 3D building database of Tokyo, New York, Paris, Melbourne, Istanbul, Jakarta and so on. Regression equations were then derived from the block-averaging of spatial pairs of real parameters and global datasets. Results show that two regression curves to estimate Have and λf from the combination of population and nightlight are necessary depending on the city's level of development. An index which can be used to decide which equation to use for a city is the Gross Domestic Product (GDP). On the other hand, λphas less dependence on GDP but indicated a negative relationship to vegetation fraction. Finally, a simplified but precise approximation of urban parameters through readily-available, high-resolution global datasets and our derived regressions can be utilized to estimate a

  13. EMMA model: an advanced operational mesoscale air quality model for urban and regional environments

    International Nuclear Information System (INIS)

    Jose, R.S.; Rodriguez, M.A.; Cortes, E.; Gonzalez, R.M.

    1999-01-01

    Mesoscale air quality models are an important tool to forecast and analyse the air quality in regional and urban areas. In recent years an increased interest has been shown by decision makers in these types of software tools. The complexity of such a model has grown exponentially with the increase of computer power. Nowadays, medium workstations can run operational versions of these modelling systems successfully. Presents a complex mesoscale air quality model which has been installed in the Environmental Office of the Madrid community (Spain) in order to forecast accurately the ozone, nitrogen dioxide and sulphur dioxide air concentrations in a 3D domain centred on Madrid city. Describes the challenging scientific matters to be solved in order to develop an operational version of the atmospheric mesoscale numerical pollution model for urban and regional areas (ANA). Some encouraging results have been achieved in the attempts to improve the accuracy of the predictions made by the version already installed. (Author)

  14. A Mobile Sensor Network to Map CO2 in Urban Environments

    Science.gov (United States)

    Lee, J.; Christen, A.; Nesic, Z.; Ketler, R.

    2014-12-01

    Globally, an estimated 80% of all fuel-based CO2 emissions into the atmosphere are attributable to cities, but there is still a lack of tools to map, visualize and monitor emissions to the scales at which emissions reduction strategies can be implemented - the local and urban scale. Mobile CO2 sensors, such as those attached to taxis and other existing mobile platforms, may be a promising way to observe and map CO2 mixing ratios across heterogenous urban environments with a limited number of sensors. Emerging modular open source technologies, and inexpensive compact sensor components not only enable rapid prototyping and replication, but also are allowing for the miniaturization and mobilization of traditionally fixed sensor networks. We aim to optimize the methods and technologies for monitoring CO2 in cities using a network of CO2 sensors deployable on vehicles and bikes. Our sensor technology is contained in a compact weather-proof case (35.8cm x 27.8cm x 11.8cm), powered independently by battery or by car, and includes the Li-Cor Li-820 infrared gas analyzer (Licor Inc, lincoln, NB, USA), Arduino Mega microcontroller (Arduino CC, Italy) and Adafruit GPS (Adafruit Technologies, NY, USA), and digital air temperature thermometer which measure CO2 mixing ratios (ppm), geolocation and speed, pressure and temperature, respectively at 1-second intervals. With the deployment of our sensor technology, we will determine if such a semi-autonomous mobile approach to monitoring CO2 in cities can determine excess urban CO2 mixing ratios (i.e. the 'urban CO2 dome') when compared to values measured at a fixed, remote background site. We present results from a pilot study in Vancouver, BC, where the a network of our new sensors was deployed both in fixed network and in a mobile campaign and examine the spatial biases of the two methods.

  15. A web GIS based integrated flood assessment modeling tool for coastal urban watersheds

    Science.gov (United States)

    Kulkarni, A. T.; Mohanty, J.; Eldho, T. I.; Rao, E. P.; Mohan, B. K.

    2014-03-01

    Urban flooding has become an increasingly important issue in many parts of the world. In this study, an integrated flood assessment model (IFAM) is presented for the coastal urban flood simulation. A web based GIS framework has been adopted to organize the spatial datasets for the study area considered and to run the model within this framework. The integrated flood model consists of a mass balance based 1-D overland flow model, 1-D finite element based channel flow model based on diffusion wave approximation and a quasi 2-D raster flood inundation model based on the continuity equation. The model code is written in MATLAB and the application is integrated within a web GIS server product viz: Web Gram Server™ (WGS), developed at IIT Bombay, using Java, JSP and JQuery technologies. Its user interface is developed using open layers and the attribute data are stored in MySQL open source DBMS. The model is integrated within WGS and is called via Java script. The application has been demonstrated for two coastal urban watersheds of Navi Mumbai, India. Simulated flood extents for extreme rainfall event of 26 July, 2005 in the two urban watersheds of Navi Mumbai city are presented and discussed. The study demonstrates the effectiveness of the flood simulation tool in a web GIS environment to facilitate data access and visualization of GIS datasets and simulation results.

  16. Extracting Urban Morphology for Atmospheric Modeling from Multispectral and SAR Satellite Imagery

    Science.gov (United States)

    Wittke, S.; Karila, K.; Puttonen, E.; Hellsten, A.; Auvinen, M.; Karjalainen, M.

    2017-05-01

    This paper presents an approach designed to derive an urban morphology map from satellite data while aiming to minimize the cost of data and user interference. The approach will help to provide updates to the current morphological databases around the world. The proposed urban morphology maps consist of two layers: 1) Digital Elevation Model (DEM) and 2) land cover map. Sentinel-2 data was used to create a land cover map, which was realized through image classification using optical range indices calculated from image data. For the purpose of atmospheric modeling, the most important classes are water and vegetation areas. The rest of the area includes bare soil and built-up areas among others, and they were merged into one class in the end. The classification result was validated with ground truth data collected both from field measurements and aerial imagery. The overall classification accuracy for the three classes is 91 %. TanDEM-X data was processed into two DEMs with different grid sizes using interferometric SAR processing. The resulting DEM has a RMSE of 3.2 meters compared to a high resolution DEM, which was estimated through 20 control points in flat areas. Comparing the derived DEM with the ground truth DEM from airborne LIDAR data, it can be seen that the street canyons, that are of high importance for urban atmospheric modeling are not detectable in the TanDEM-X DEM. However, the derived DEM is suitable for a class of urban atmospheric models. Based on the numerical modeling needs for regional atmospheric pollutant dispersion studies, the generated files enable the extraction of relevant parametrizations, such as Urban Canopy Parameters (UCP).

  17. EXTRACTING URBAN MORPHOLOGY FOR ATMOSPHERIC MODELING FROM MULTISPECTRAL AND SAR SATELLITE IMAGERY

    Directory of Open Access Journals (Sweden)

    S. Wittke

    2017-05-01

    Full Text Available This paper presents an approach designed to derive an urban morphology map from satellite data while aiming to minimize the cost of data and user interference. The approach will help to provide updates to the current morphological databases around the world. The proposed urban morphology maps consist of two layers: 1 Digital Elevation Model (DEM and 2 land cover map. Sentinel-2 data was used to create a land cover map, which was realized through image classification using optical range indices calculated from image data. For the purpose of atmospheric modeling, the most important classes are water and vegetation areas. The rest of the area includes bare soil and built-up areas among others, and they were merged into one class in the end. The classification result was validated with ground truth data collected both from field measurements and aerial imagery. The overall classification accuracy for the three classes is 91 %. TanDEM-X data was processed into two DEMs with different grid sizes using interferometric SAR processing. The resulting DEM has a RMSE of 3.2 meters compared to a high resolution DEM, which was estimated through 20 control points in flat areas. Comparing the derived DEM with the ground truth DEM from airborne LIDAR data, it can be seen that the street canyons, that are of high importance for urban atmospheric modeling are not detectable in the TanDEM-X DEM. However, the derived DEM is suitable for a class of urban atmospheric models. Based on the numerical modeling needs for regional atmospheric pollutant dispersion studies, the generated files enable the extraction of relevant parametrizations, such as Urban Canopy Parameters (UCP.

  18. Bayesian uncertainty assessment of flood predictions in ungauged urban basins for conceptual rainfall-runoff models

    Directory of Open Access Journals (Sweden)

    A. E. Sikorska

    2012-04-01

    Full Text Available Urbanization and the resulting land-use change strongly affect the water cycle and runoff-processes in watersheds. Unfortunately, small urban watersheds, which are most affected by urban sprawl, are mostly ungauged. This makes it intrinsically difficult to assess the consequences of urbanization. Most of all, it is unclear how to reliably assess the predictive uncertainty given the structural deficits of the applied models. In this study, we therefore investigate the uncertainty of flood predictions in ungauged urban basins from structurally uncertain rainfall-runoff models. To this end, we suggest a procedure to explicitly account for input uncertainty and model structure deficits using Bayesian statistics with a continuous-time autoregressive error model. In addition, we propose a concise procedure to derive prior parameter distributions from base data and successfully apply the methodology to an urban catchment in Warsaw, Poland. Based on our results, we are able to demonstrate that the autoregressive error model greatly helps to meet the statistical assumptions and to compute reliable prediction intervals. In our study, we found that predicted peak flows were up to 7 times higher than observations. This was reduced to 5 times with Bayesian updating, using only few discharge measurements. In addition, our analysis suggests that imprecise rainfall information and model structure deficits contribute mostly to the total prediction uncertainty. In the future, flood predictions in ungauged basins will become more important due to ongoing urbanization as well as anthropogenic and climatic changes. Thus, providing reliable measures of uncertainty is crucial to support decision making.

  19. Merging of rain gauge and radar data for urban hydrological modelling

    Science.gov (United States)

    Berndt, Christian; Haberlandt, Uwe

    2015-04-01

    Urban hydrological processes are generally characterised by short response times and therefore rainfall data with a high resolution in space and time are required for their modelling. In many smaller towns, no recordings of rainfall data exist within the urban catchment. Precipitation radar helps to provide extensive rainfall data with a temporal resolution of five minutes, but the rainfall amounts can be highly biased and hence the data should not be used directly as a model input. However, scientists proposed several methods for adjusting radar data to station measurements. This work tries to evaluate rainfall inputs for a hydrological model regarding the following two different applications: Dimensioning of urban drainage systems and analysis of single event flow. The input data used for this analysis can be divided into two groups: Methods, which rely on station data only (Nearest Neighbour Interpolation, Ordinary Kriging), and methods, which incorporate station as well as radar information (Conditional Merging, Bias correction of radar data based on quantile mapping with rain gauge recordings). Additionally, rainfall intensities that were directly obtained from radar reflectivities are used. A model of the urban catchment of the city of Brunswick (Lower Saxony, Germany) is utilised for the evaluation. First results show that radar data cannot help with the dimensioning task of sewer systems since rainfall amounts of convective events are often overestimated. Gauges in catchment proximity can provide more reliable rainfall extremes. Whether radar data can be helpful to simulate single event flow depends strongly on the data quality and thus on the selected event. Ordinary Kriging is often not suitable for the interpolation of rainfall data in urban hydrology. This technique induces a strong smoothing of rainfall fields and therefore a severe underestimation of rainfall intensities for convective events.

  20. Fine-resolution Modeling of Urban-Energy Systems' Water Footprint in River Networks

    Science.gov (United States)

    McManamay, R.; Surendran Nair, S.; Morton, A.; DeRolph, C.; Stewart, R.

    2015-12-01

    Characterizing the interplay between urbanization, energy production, and water resources is essential for ensuring sustainable population growth. In order to balance limited water supplies, competing users must account for their realized and virtual water footprint, i.e. the total direct and indirect amount of water used, respectively. Unfortunately, publicly reported US water use estimates are spatially coarse, temporally static, and completely ignore returns of water to rivers after use. These estimates are insufficient to account for the high spatial and temporal heterogeneity of water budgets in urbanizing systems. Likewise, urbanizing areas are supported by competing sources of energy production, which also have heterogeneous water footprints. Hence, a fundamental challenge of planning for sustainable urban growth and decision-making across disparate policy sectors lies in characterizing inter-dependencies among urban systems, energy producers, and water resources. A modeling framework is presented that provides a novel approach to integrate urban-energy infrastructure into a spatial accounting network that accurately measures water footprints as changes in the quantity and quality of river flows. River networks (RNs), i.e. networks of branching tributaries nested within larger rivers, provide a spatial structure to measure water budgets by modeling hydrology and accounting for use and returns from urbanizing areas and energy producers. We quantify urban-energy water footprints for Atlanta, GA and Knoxville, TN (USA) based on changes in hydrology in RNs. Although water intakes providing supply to metropolitan areas were proximate to metropolitan areas, power plants contributing to energy demand in Knoxville and Atlanta, occurred 30 and 90km outside the metropolitan boundary, respectively. Direct water footprints from urban landcover primarily comprised smaller streams whereas indirect footprints from water supply reservoirs and energy producers included

  1. A model library for simulation and benchmarking of integrated urban wastewater systems

    DEFF Research Database (Denmark)

    Saagi, R.; Flores Alsina, Xavier; Kroll, J. S.

    2017-01-01

    This paper presents a freely distributed, open-source toolbox to predict the behaviour of urban wastewater systems (UWS). The proposed library is used to develop a system-wide Benchmark Simulation Model (BSM-UWS) for evaluating (local/global) control strategies in urban wastewater systems (UWS...

  2. High-resolution stochastic generation of extreme rainfall intensity for urban drainage modelling applications

    Science.gov (United States)

    Peleg, Nadav; Blumensaat, Frank; Molnar, Peter; Fatichi, Simone; Burlando, Paolo

    2016-04-01

    Urban drainage response is highly dependent on the spatial and temporal structure of rainfall. Therefore, measuring and simulating rainfall at a high spatial and temporal resolution is a fundamental step to fully assess urban drainage system reliability and related uncertainties. This is even more relevant when considering extreme rainfall events. However, the current space-time rainfall models have limitations in capturing extreme rainfall intensity statistics for short durations. Here, we use the STREAP (Space-Time Realizations of Areal Precipitation) model, which is a novel stochastic rainfall generator for simulating high-resolution rainfall fields that preserve the spatio-temporal structure of rainfall and its statistical characteristics. The model enables a generation of rain fields at 102 m and minute scales in a fast and computer-efficient way matching the requirements for hydrological analysis of urban drainage systems. The STREAP model was applied successfully in the past to generate high-resolution extreme rainfall intensities over a small domain. A sub-catchment in the city of Luzern (Switzerland) was chosen as a case study to: (i) evaluate the ability of STREAP to disaggregate extreme rainfall intensities for urban drainage applications; (ii) assessing the role of stochastic climate variability of rainfall in flow response and (iii) evaluate the degree of non-linearity between extreme rainfall intensity and system response (i.e. flow) for a small urban catchment. The channel flow at the catchment outlet is simulated by means of a calibrated hydrodynamic sewer model.

  3. Modeling urbanization patterns with generative adversarial networks

    OpenAIRE

    Albert, Adrian; Strano, Emanuele; Kaur, Jasleen; Gonzalez, Marta

    2018-01-01

    In this study we propose a new method to simulate hyper-realistic urban patterns using Generative Adversarial Networks trained with a global urban land-use inventory. We generated a synthetic urban "universe" that qualitatively reproduces the complex spatial organization observed in global urban patterns, while being able to quantitatively recover certain key high-level urban spatial metrics.

  4. [Location selection for Shenyang urban parks based on GIS and multi-objective location allocation model].

    Science.gov (United States)

    Zhou, Yuan; Shi, Tie-Mao; Hu, Yuan-Man; Gao, Chang; Liu, Miao; Song, Lin-Qi

    2011-12-01

    Based on geographic information system (GIS) technology and multi-objective location-allocation (LA) model, and in considering of four relatively independent objective factors (population density level, air pollution level, urban heat island effect level, and urban land use pattern), an optimized location selection for the urban parks within the Third Ring of Shenyang was conducted, and the selection results were compared with the spatial distribution of existing parks, aimed to evaluate the rationality of the spatial distribution of urban green spaces. In the location selection of urban green spaces in the study area, the factor air pollution was most important, and, compared with single objective factor, the weighted analysis results of multi-objective factors could provide optimized spatial location selection of new urban green spaces. The combination of GIS technology with LA model would be a new approach for the spatial optimizing of urban green spaces.

  5. Designing and implementing a regional urban modeling system using the SLEUTH cellular urban model

    Science.gov (United States)

    Jantz, Claire A.; Goetz, Scott J.; Donato, David I.; Claggett, Peter

    2010-01-01

    This paper presents a fine-scale (30 meter resolution) regional land cover modeling system, based on the SLEUTH cellular automata model, that was developed for a 257000 km2 area comprising the Chesapeake Bay drainage basin in the eastern United States. As part of this effort, we developed a new version of the SLEUTH model (SLEUTH-3r), which introduces new functionality and fit metrics that substantially increase the performance and applicability of the model. In addition, we developed methods that expand the capability of SLEUTH to incorporate economic, cultural and policy information, opening up new avenues for the integration of SLEUTH with other land-change models. SLEUTH-3r is also more computationally efficient (by a factor of 5) and uses less memory (reduced 65%) than the original software. With the new version of SLEUTH, we were able to achieve high accuracies at both the aggregate level of 15 sub-regional modeling units and at finer scales. We present forecasts to 2030 of urban development under a current trends scenario across the entire Chesapeake Bay drainage basin, and three alternative scenarios for a sub-region within the Chesapeake Bay watershed to illustrate the new ability of SLEUTH-3r to generate forecasts across a broad range of conditions.

  6. Urban Stormwater Management Model and Tools for Designing Stormwater Management of Green Infrastructure Practices

    Science.gov (United States)

    Haris, H.; Chow, M. F.; Usman, F.; Sidek, L. M.; Roseli, Z. A.; Norlida, M. D.

    2016-03-01

    Urbanization is growing rapidly in Malaysia. Rapid urbanization has known to have several negative impacts towards hydrological cycle due to decreasing of pervious area and deterioration of water quality in stormwater runoff. One of the negative impacts of urbanization is the congestion of the stormwater drainage system and this situation leading to flash flood problem and water quality degradation. There are many urban stormwater management softwares available in the market such as Storm Water Drainage System design and analysis program (DRAINS), Urban Drainage and Sewer Model (MOUSE), InfoWorks River Simulation (InfoWork RS), Hydrological Simulation Program-Fortran (HSPF), Distributed Routing Rainfall-Runoff Model (DR3M), Storm Water Management Model (SWMM), XP Storm Water Management Model (XPSWMM), MIKE-SWMM, Quality-Quantity Simulators (QQS), Storage, Treatment, Overflow, Runoff Model (STORM), and Hydrologic Engineering Centre-Hydrologic Modelling System (HEC-HMS). In this paper, we are going to discuss briefly about several softwares and their functionality, accessibility, characteristics and components in the quantity analysis of the hydrological design software and compare it with MSMA Design Aid and Database. Green Infrastructure (GI) is one of the main topics that has widely been discussed all over the world. Every development in the urban area is related to GI. GI can be defined as green area build in the develop area such as forest, park, wetland or floodway. The role of GI is to improve life standard such as water filtration or flood control. Among the twenty models that have been compared to MSMA SME, ten models were selected to conduct a comprehensive review for this study. These are known to be widely accepted by water resource researchers. These ten tools are further classified into three major categories as models that address the stormwater management ability of GI in terms of quantity and quality, models that have the capability of conducting the

  7. A hybrid multiview stereo algorithm for modeling urban scenes.

    Science.gov (United States)

    Lafarge, Florent; Keriven, Renaud; Brédif, Mathieu; Vu, Hoang-Hiep

    2013-01-01

    We present an original multiview stereo reconstruction algorithm which allows the 3D-modeling of urban scenes as a combination of meshes and geometric primitives. The method provides a compact model while preserving details: Irregular elements such as statues and ornaments are described by meshes, whereas regular structures such as columns and walls are described by primitives (planes, spheres, cylinders, cones, and tori). We adopt a two-step strategy consisting first in segmenting the initial meshbased surface using a multilabel Markov Random Field-based model and second in sampling primitive and mesh components simultaneously on the obtained partition by a Jump-Diffusion process. The quality of a reconstruction is measured by a multi-object energy model which takes into account both photo-consistency and semantic considerations (i.e., geometry and shape layout). The segmentation and sampling steps are embedded into an iterative refinement procedure which provides an increasingly accurate hybrid representation. Experimental results on complex urban structures and large scenes are presented and compared to state-of-the-art multiview stereo meshing algorithms.

  8. Urban nonpoint source pollution buildup and washoff models for simulating storm runoff quality in the Los Angeles County

    International Nuclear Information System (INIS)

    Wang Long; Wei Jiahua; Huang Yuefei; Wang Guangqian; Maqsood, Imran

    2011-01-01

    Many urban nonpoint source pollution models utilize pollutant buildup and washoff functions to simulate storm runoff quality of urban catchments. In this paper, two urban pollutant washoff load models are derived using pollutant buildup and washoff functions. The first model assumes that there is no residual pollutant after a storm event while the second one assumes that there is always residual pollutant after each storm event. The developed models are calibrated and verified with observed data from an urban catchment in the Los Angeles County. The application results show that the developed model with consideration of residual pollutant is more capable of simulating nonpoint source pollution from urban storm runoff than that without consideration of residual pollutant. For the study area, residual pollutant should be considered in pollutant buildup and washoff functions for simulating urban nonpoint source pollution when the total runoff volume is less than 30 mm. - Highlights: → An improved urban NPS model was developed. → It performs well in areas where storm events have great temporal variation. → Threshold of total runoff volume for ignoring residual pollutant was determined. - An improved urban NPS model was developed. Threshold of total runoff volume for ignoring residual pollutant was determined.

  9. Unstructured mesh adaptivity for urban flooding modelling

    Science.gov (United States)

    Hu, R.; Fang, F.; Salinas, P.; Pain, C. C.

    2018-05-01

    Over the past few decades, urban floods have been gaining more attention due to their increase in frequency. To provide reliable flooding predictions in urban areas, various numerical models have been developed to perform high-resolution flood simulations. However, the use of high-resolution meshes across the whole computational domain causes a high computational burden. In this paper, a 2D control-volume and finite-element flood model using adaptive unstructured mesh technology has been developed. This adaptive unstructured mesh technique enables meshes to be adapted optimally in time and space in response to the evolving flow features, thus providing sufficient mesh resolution where and when it is required. It has the advantage of capturing the details of local flows and wetting and drying front while reducing the computational cost. Complex topographic features are represented accurately during the flooding process. For example, the high-resolution meshes around the buildings and steep regions are placed when the flooding water reaches these regions. In this work a flooding event that happened in 2002 in Glasgow, Scotland, United Kingdom has been simulated to demonstrate the capability of the adaptive unstructured mesh flooding model. The simulations have been performed using both fixed and adaptive unstructured meshes, and then results have been compared with those published 2D and 3D results. The presented method shows that the 2D adaptive mesh model provides accurate results while having a low computational cost.

  10. An Improved Algorithm to Delineate Urban Targets with Model-Based Decomposition of PolSAR Data

    Directory of Open Access Journals (Sweden)

    Dingfeng Duan

    2017-10-01

    Full Text Available In model-based decomposition algorithms using polarimetric synthetic aperture radar (PolSAR data, urban targets are typically identified based on the existence of strong double-bounced scattering. However, urban targets with large azimuth orientation angles (AOAs produce strong volumetric scattering that appears similar to scattering characteristics from tree canopies. Due to scattering ambiguity, urban targets can be classified into the vegetation category if the same classification scheme of the model-based PolSAR decomposition algorithms is followed. To resolve the ambiguity and to reduce the misclassification eventually, we introduced a correlation coefficient that characterized scattering mechanisms of urban targets with variable AOAs. Then, an existing volumetric scattering model was modified, and a PolSAR decomposition algorithm developed. The validity and effectiveness of the algorithm were examined using four PolSAR datasets. The algorithm was valid and effective to delineate urban targets with a wide range of AOAs, and applicable to a broad range of ground targets from urban areas, and from upland and flooded forest stands.

  11. Detailed Urban Heat Island Projections for Cities Worldwide: Dynamical Downscaling CMIP5 Global Climate Models

    Directory of Open Access Journals (Sweden)

    Dirk Lauwaet

    2015-06-01

    Full Text Available A new dynamical downscaling methodology to analyze the impact of global climate change on the local climate of cities worldwide is presented. The urban boundary layer climate model UrbClim is coupled to 11 global climate models contained in the Coupled Model Intercomparison Project 5 archive, conducting 20-year simulations for present (1986–2005 and future (2081–2100 climate conditions, considering the Representative Concentration Pathway 8.5 climate scenario. The evolution of the urban heat island of eight different cities, located on three continents, is quantified and assessed, with an unprecedented horizontal resolution of a few hundred meters. For all cities, urban and rural air temperatures are found to increase strongly, up to 7 °C. However, the urban heat island intensity in most cases increases only slightly, often even below the range of uncertainty. A potential explanation, focusing on the role of increased incoming longwave radiation, is put forth. Finally, an alternative method for generating urban climate projections is proposed, combining the ensemble temperature change statistics and the results of the present-day urban climate.

  12. Safety evaluation model of urban cross-river tunnel based on driving simulation.

    Science.gov (United States)

    Ma, Yingqi; Lu, Linjun; Lu, Jian John

    2017-09-01

    Currently, Shanghai urban cross-river tunnels have three principal characteristics: increased traffic, a high accident rate and rapidly developing construction. Because of their complex geographic and hydrological characteristics, the alignment conditions in urban cross-river tunnels are more complicated than in highway tunnels, so a safety evaluation of urban cross-river tunnels is necessary to suggest follow-up construction and changes in operational management. A driving risk index (DRI) for urban cross-river tunnels was proposed in this study. An index system was also constructed, combining eight factors derived from the output of a driving simulator regarding three aspects of risk due to following, lateral accidents and driver workload. Analytic hierarchy process methods and expert marking and normalization processing were applied to construct a mathematical model for the DRI. The driving simulator was used to simulate 12 Shanghai urban cross-river tunnels and a relationship was obtained between the DRI for the tunnels and the corresponding accident rate (AR) via a regression analysis. The regression analysis results showed that the relationship between the DRI and the AR mapped to an exponential function with a high degree of fit. In the absence of detailed accident data, a safety evaluation model based on factors derived from a driving simulation can effectively assess the driving risk in urban cross-river tunnels constructed or in design.

  13. Human-Induced Climate Variations Linked to Urbanization: From Observations to Modeling

    Science.gov (United States)

    Shepherd, J. Marshall; Jin, Menglin

    2004-01-01

    The goal of this session is to bring together scientists from interdisciplinary backgrounds to discuss the data, scientific approaches and recent results focusing on the impact of urbanization on the climate. The discussion will highlight current observational and modeling capabilities being employed for investigating the urban environment and its linkage to the change in the Earth's climate system. The goal of the session is to identify our current stand and the future direction on the topic. Urbanization is one of the extreme cases of land use change. Most of population of the world has moved to urban areas. By 1995, more than 70% of population of North America and Europe were living in cities. By 2025, the United Nations estimates that 60% of the worlds population will live in cities. Although currently only 1.2% of the land is urban, better understanding of how the atmosphere-ocean-land-biosphere components interact as a coupled system and the influence of human activities on this system is critical. Our understanding of urbanization effect is incomplete, partly because human activities induce new changes on climate in addition to the original natural variations, and partly because previously few data available for study urban effect globally. Urban construction changes surface roughness, albedo, heat capacity and vegetation coverage. Traffic and industry increase atmospheric aerosol. It is suggested that urbanization may modify rainfall processes through aerosol-cloud interactions or dynamic feedbacks. Because urbanization effect on climate is determined by many factors including land cover, the city's microscale features, population density, and human lifestyle patterns, it is necessary to study urban areas over globe.

  14. Urban Landscape Characterization Using Remote Sensing Data For Input into Air Quality Modeling

    Science.gov (United States)

    Quattrochi, Dale A.; Estes, Maurice G., Jr.; Crosson, William; Khan, Maudood

    2005-01-01

    The urban landscape is inherently complex and this complexity is not adequately captured in air quality models that are used to assess whether urban areas are in attainment of EPA air quality standards, particularly for ground level ozone. This inadequacy of air quality models to sufficiently respond to the heterogeneous nature of the urban landscape can impact how well these models predict ozone pollutant levels over metropolitan areas and ultimately, whether cities exceed EPA ozone air quality standards. We are exploring the utility of high-resolution remote sensing data and urban growth projections as improved inputs to meteorological and air quality models focusing on the Atlanta, Georgia metropolitan area as a case study. The National Land Cover Dataset at 30m resolution is being used as the land use/land cover input and aggregated to the 4km scale for the MM5 mesoscale meteorological model and the Community Multiscale Air Quality (CMAQ) modeling schemes. Use of these data have been found to better characterize low density/suburban development as compared with USGS 1 km land use/land cover data that have traditionally been used in modeling. Air quality prediction for future scenarios to 2030 is being facilitated by land use projections using a spatial growth model. Land use projections were developed using the 2030 Regional Transportation Plan developed by the Atlanta Regional Commission. This allows the State Environmental Protection agency to evaluate how these transportation plans will affect future air quality.

  15. Integration of aerial oblique imagery and terrestrial imagery for optimized 3D modeling in urban areas

    Science.gov (United States)

    Wu, Bo; Xie, Linfu; Hu, Han; Zhu, Qing; Yau, Eric

    2018-05-01

    Photorealistic three-dimensional (3D) models are fundamental to the spatial data infrastructure of a digital city, and have numerous potential applications in areas such as urban planning, urban management, urban monitoring, and urban environmental studies. Recent developments in aerial oblique photogrammetry based on aircraft or unmanned aerial vehicles (UAVs) offer promising techniques for 3D modeling. However, 3D models generated from aerial oblique imagery in urban areas with densely distributed high-rise buildings may show geometric defects and blurred textures, especially on building façades, due to problems such as occlusion and large camera tilt angles. Meanwhile, mobile mapping systems (MMSs) can capture terrestrial images of close-range objects from a complementary view on the ground at a high level of detail, but do not offer full coverage. The integration of aerial oblique imagery with terrestrial imagery offers promising opportunities to optimize 3D modeling in urban areas. This paper presents a novel method of integrating these two image types through automatic feature matching and combined bundle adjustment between them, and based on the integrated results to optimize the geometry and texture of the 3D models generated from aerial oblique imagery. Experimental analyses were conducted on two datasets of aerial and terrestrial images collected in Dortmund, Germany and in Hong Kong. The results indicate that the proposed approach effectively integrates images from the two platforms and thereby improves 3D modeling in urban areas.

  16. Representing soakaways in a physically distributed urban drainage model – Upscaling individual allotments to an aggregated scale

    DEFF Research Database (Denmark)

    Roldin, Maria Kerstin; Mark, Ole; Kuczera, George

    2012-01-01

    the infiltration rate based on water depth and soil properties for each time step, and controls the removal of water from the urban drainage model. The model is intended to be used to assess the impact of soakaways on urban drainage networks. The model is tested using field data and shown to simulate the behavior......The increased load on urban stormwater systems due to climate change and growing urbanization can be partly alleviated by using soakaways and similar infiltration techniques. However, while soakaways are usually small-scale structures, most urban drainage network models operate on a larger spatial...... of individual soakaways well. Six upscaling methods to aggregate individual soakaway units with varying saturated hydraulic conductivity (K) in the surrounding soil have been investigated. In the upscaled model, the weighted geometric mean hydraulic conductivity of individual allotments is found to provide...

  17. A tool for urban soundscape evaluation applying Support Vector Machines for developing a soundscape classification model.

    Science.gov (United States)

    Torija, Antonio J; Ruiz, Diego P; Ramos-Ridao, Angel F

    2014-06-01

    To ensure appropriate soundscape management in urban environments, the urban-planning authorities need a range of tools that enable such a task to be performed. An essential step during the management of urban areas from a sound standpoint should be the evaluation of the soundscape in such an area. In this sense, it has been widely acknowledged that a subjective and acoustical categorization of a soundscape is the first step to evaluate it, providing a basis for designing or adapting it to match people's expectations as well. In this sense, this work proposes a model for automatic classification of urban soundscapes. This model is intended for the automatic classification of urban soundscapes based on underlying acoustical and perceptual criteria. Thus, this classification model is proposed to be used as a tool for a comprehensive urban soundscape evaluation. Because of the great complexity associated with the problem, two machine learning techniques, Support Vector Machines (SVM) and Support Vector Machines trained with Sequential Minimal Optimization (SMO), are implemented in developing model classification. The results indicate that the SMO model outperforms the SVM model in the specific task of soundscape classification. With the implementation of the SMO algorithm, the classification model achieves an outstanding performance (91.3% of instances correctly classified). © 2013 Elsevier B.V. All rights reserved.

  18. 1D and 2D urban dam-break flood modelling in Istanbul, Turkey

    Science.gov (United States)

    Ozdemir, Hasan; Neal, Jeffrey; Bates, Paul; Döker, Fatih

    2014-05-01

    Urban flood events are increasing in frequency and severity as a consequence of several factors such as reduced infiltration capacities due to continued watershed development, increased construction in flood prone areas due to population growth, the possible amplification of rainfall intensity due to climate change, sea level rise which threatens coastal development, and poorly engineered flood control infrastructure (Gallegos et al., 2009). These factors will contribute to increased urban flood risk in the future, and as a result improved modelling of urban flooding according to different causative factor has been identified as a research priority (Gallegos et al., 2009; Ozdemir et al. 2013). The flooding disaster caused by dam failures is always a threat against lives and properties especially in urban environments. Therefore, the prediction of dynamics of dam-break flows plays a vital role in the forecast and evaluation of flooding disasters, and is of long-standing interest for researchers. Flooding occurred on the Ayamama River (Istanbul-Turkey) due to high intensity rainfall and dam-breaching of Ata Pond in 9th September 2009. The settlements, industrial areas and transportation system on the floodplain of the Ayamama River were inundated. Therefore, 32 people were dead and millions of Euros economic loses were occurred. The aim of this study is 1 and 2-Dimensional flood modelling of the Ata Pond breaching using HEC-RAS and LISFLOOD-Roe models and comparison of the model results using the real flood extent. The HEC-RAS model solves the full 1-D Saint Venant equations for unsteady open channel flow whereas LISFLOOD-Roe is the 2-D shallow water model which calculates the flow according to the complete Saint Venant formulation (Villanueva and Wright, 2006; Neal et al., 2011). The model consists a shock capturing Godunov-type scheme based on the Roe Riemann solver (Roe, 1981). 3 m high resolution Digital Surface Model (DSM), natural characteristics of the pond

  19. Exploring the patterns and evolution of self-organized urban street networks through modeling

    Science.gov (United States)

    Rui, Yikang; Ban, Yifang; Wang, Jiechen; Haas, Jan

    2013-03-01

    As one of the most important subsystems in cities, urban street networks have recently been well studied by using the approach of complex networks. This paper proposes a growing model for self-organized urban street networks. The model involves a competition among new centers with different values of attraction radius and a local optimal principle of both geometrical and topological factors. We find that with the model growth, the local optimization in the connection process and appropriate probability for the loop construction well reflect the evolution strategy in real-world cities. Moreover, different values of attraction radius in centers competition process lead to morphological change in patterns including urban network, polycentric and monocentric structures. The model succeeds in reproducing a large diversity of road network patterns by varying parameters. The similarity between the properties of our model and empirical results implies that a simple universal growth mechanism exists in self-organized cities.

  20. An u-Service Model Based on a Smart Phone for Urban Computing Environments

    Science.gov (United States)

    Cho, Yongyun; Yoe, Hyun

    In urban computing environments, all of services should be based on the interaction between humans and environments around them, which frequently and ordinarily in home and office. This paper propose an u-service model based on a smart phone for urban computing environments. The suggested service model includes a context-aware and personalized service scenario development environment that can instantly describe user's u-service demand or situation information with smart devices. To do this, the architecture of the suggested service model consists of a graphical service editing environment for smart devices, an u-service platform, and an infrastructure with sensors and WSN/USN. The graphic editor expresses contexts as execution conditions of a new service through a context model based on ontology. The service platform deals with the service scenario according to contexts. With the suggested service model, an user in urban computing environments can quickly and easily make u-service or new service using smart devices.

  1. Low-Carbon Transportation Oriented Urban Spatial Structure: Theory, Model and Case Study

    Directory of Open Access Journals (Sweden)

    Yuyao Ye

    2017-12-01

    Full Text Available Optimising the spatial structure of cities to promote low-carbon travel is a primary goal of urban planning and construction innovation in the low-carbon era. There is a need for basic research on the structural characteristics that help to reduce motor traffic, thereby promoting energy conservation. We first review the existing literature on the influence of urban spatial structure on transport carbon dioxide emissions and summarise the influence mechanisms. We then present two low-carbon transportation oriented patterns of urban spatial structure including the traditional walking city and the modern transit metropolis, illustrated by case studies. Furthermore, we propose an improved model Green Transportation System Oriented Development (GTOD, which is an extension of traditional transit-oriented development (TOD and includes the additional features of a walking city and an emphasis on the integration of land use with a green transportation system, consisting of the public transportation and non-auto travel system. A compact urban form, effective mix of land use and appropriate scale of block are the basic structural features of a low-carbon transportation city. However, these features are only effective at promoting low-carbon transportation when integrated with the green traffic systems. Proper integration of the urban structural system with the green space system is also required. The optimal land use/transportation integration strategy is to divide traffic corridors with wedge-shaped green spaces and limit development along the transit corridors. This strategy forms the basis of the proposed urban structural model to promote low-carbon transportation and sustainable urban growth management.

  2. Modeling Boston: A workflow for the efficient generation and maintenance of urban building energy models from existing geospatial datasets

    International Nuclear Information System (INIS)

    Cerezo Davila, Carlos; Reinhart, Christoph F.; Bemis, Jamie L.

    2016-01-01

    City governments and energy utilities are increasingly focusing on the development of energy efficiency strategies for buildings as a key component in emission reduction plans and energy supply strategies. To support these diverse needs, a new generation of Urban Building Energy Models (UBEM) is currently being developed and validated to estimate citywide hourly energy demands at the building level. However, in order for cities to rely on UBEMs, effective model generation and maintenance workflows are needed based on existing urban data structures. Within this context, the authors collaborated with the Boston Redevelopment Authority to develop a citywide UBEM based on official GIS datasets and a custom building archetype library. Energy models for 83,541 buildings were generated and assigned one of 52 use/age archetypes, within the CAD modelling environment Rhinoceros3D. The buildings were then simulated using the US DOE EnergyPlus simulation program, and results for buildings of the same archetype were crosschecked against data from the US national energy consumption surveys. A district-level intervention combining photovoltaics with demand side management is presented to demonstrate the ability of UBEM to provide actionable information. Lack of widely available archetype templates and metered energy data, were identified as key barriers within existing workflows that may impede cities from effectively applying UBEM to guide energy policy. - Highlights: • Data requirements for Urban Building Energy Models are reviewed. • A workflow for UBEM generation from available GIS datasets is developed. • A citywide demand simulation model for Boston is generated and tested. • Limitations for UBEM in current urban data systems are identified and discussed. • Model application for energy management policy is shown in an urban PV scenario.

  3. Modelling of a large-scale urban contamination situation and remediation alternatives

    International Nuclear Information System (INIS)

    Thiessen, K.M.; Arkhipov, A.; Batandjieva, B.; Charnock, T.W.; Gaschak, S.; Golikov, V.; Hwang, W.T.; Tomas, J.; Zlobenko, B.

    2009-01-01

    The Urban Remediation Working Group of the International Atomic Energy Agency's EMRAS (Environmental Modelling for Radiation Safety) program was organized to address issues of remediation assessment modelling for urban areas contaminated with dispersed radionuclides. The present paper describes the first of two modelling exercises, which was based on Chernobyl fallout data in the town of Pripyat, Ukraine. Modelling endpoints for the exercise included radionuclide concentrations and external dose rates at specified locations, contributions to the dose rates from individual surfaces and radionuclides, and annual and cumulative external doses to specified reference individuals. Model predictions were performed for a 'no action' situation (with no remedial measures) and for selected countermeasures. The exercise provided a valuable opportunity to compare modelling approaches and parameter values, as well as to compare the predicted effectiveness of various countermeasures with respect to short-term and long-term reduction of predicted doses to people.

  4. The urban land use in the COSMO-CLM model: a comparison of three parameterizations for Berlin

    Directory of Open Access Journals (Sweden)

    Kristina Trusilova

    2016-05-01

    Full Text Available The regional non-hydrostatic climate model COSMO-CLM is increasingly being used on fine spatial scales of 1–5 km. Such applications require a detailed differentiation between the parameterization for natural and urban land uses. Since 2010, three parameterizations for urban land use have been incorporated into COSMO-CLM. These parameterizations vary in their complexity, required city parameters and their computational cost. We perform model simulations with the COSMO-CLM coupled to these three parameterizations for urban land in the same model domain of Berlin on a 1-km grid and compare results with available temperature observations. While all models capture the urban heat island, they differ in spatial detail, magnitude and the diurnal variation.

  5. Modeling the role of public transportation in sustaining tuberculosis transmission in South Africa.

    Science.gov (United States)

    Andrews, Jason R; Morrow, Carl; Wood, Robin

    2013-03-15

    Current tuberculosis notification rates in South Africa are among the highest ever recorded. Although the human immunodeficiency virus epidemic has been a critical factor, the density of respiratory contacts in high-risk environments may be an important and underappreciated driver. Using a modified Wells-Riley model for airborne disease transmission, we estimated the risk of tuberculosis transmission on 3 modes of public transit (minibus taxis, buses, and trains) in Cape Town, South Africa, using exhaled carbon dioxide as a natural tracer gas to evaluate air exchange. Carbon dioxide measurements were performed between October and December of 2011. Environmental risk, reflected in the rebreathed fraction of air, was highest in minibus taxis and lowest in trains; however, the average number of passengers sharing an indoor space was highest in trains and lowest in minibus taxis. Among daily commuters, the annual risk of tuberculosis infection was projected to be 3.5%-5.0% and was highest among minibus taxi commuters. Assuming a duration of infectiousness of 1 year, the basic reproductive number attributable to transportation was more than 1 in all 3 modes of transportation. Given its poor ventilation and high respiratory contact rates, public transportation may play a critical role in sustaining tuberculosis transmission in South African cities.

  6. A german vision of urban models. The case of Querétaro

    OpenAIRE

    Christof Göbel

    2015-01-01

    Due to their complexity, the organization, function and morphology of cities has been historically reduced to graphic abstractions or urban “models” with the intention to identify types of cities according to the cultural space in question. However, by their nature, cities are under constant change and transformation, which gives rise to many questions about the validity and the relevance of these urban models: Are these models still a way to understand the logic and structure of cities? Can ...

  7. HOTSPOTS DETECTION FROM TRAJECTORY DATA BASED ON SPATIOTEMPORAL DATA FIELD CLUSTERING

    Directory of Open Access Journals (Sweden)

    K. Qin

    2017-09-01

    Full Text Available City hotspots refer to the areas where residents visit frequently, and large traffic flow exist, which reflect the people travel patterns and distribution of urban function area. Taxi trajectory data contain abundant information about urban functions and citizen activities, and extracting interesting city hotspots from them can be of importance in urban planning, traffic command, public travel services etc. To detect city hotspots and discover a variety of changing patterns among them, we introduce a data field-based cluster analysis technique to the pick-up and drop-off points of taxi trajectory data and improve the method by introducing the time weight, which has been normalized to estimate the potential value in data field. Thus, in the light of the new potential function in data field, short distance and short time difference play a powerful role. So the region full of trajectory points, which is regarded as hotspots area, has a higher potential value, while the region with thin trajectory points has a lower potential value. The taxi trajectory data of Wuhan city in China on May 1, 6 and 9, 2015, are taken as the experimental data. From the result, we find the sustaining hotspots area and inconstant hotspots area in Wuhan city based on the spatiotemporal data field method. Further study will focus on optimizing parameter and the interaction among hotspots area.

  8. The water balance of the urban Salt Lake Valley: a multiple-box model validated by observations

    Science.gov (United States)

    Stwertka, C.; Strong, C.

    2012-12-01

    A main focus of the recently awarded National Science Foundation (NSF) EPSCoR Track-1 research project "innovative Urban Transitions and Arid-region Hydro-sustainability (iUTAH)" is to quantify the primary components of the water balance for the Wasatch region, and to evaluate their sensitivity to climate change and projected urban development. Building on the multiple-box model that we developed and validated for carbon dioxide (Strong et al 2011), mass balance equations for water in the atmosphere and surface are incorporated into the modeling framework. The model is used to determine how surface fluxes, ground-water transport, biological fluxes, and meteorological processes regulate water cycling within and around the urban Salt Lake Valley. The model is used to evaluate the hypotheses that increased water demand associated with urban growth in Salt Lake Valley will (1) elevate sensitivity to projected climate variability and (2) motivate more attentive management of urban water use and evaporative fluxes.

  9. A Novel Approach for Assessing the Performance of Sustainable Urbanization Based on Structural Equation Modeling: A China Case Study

    Directory of Open Access Journals (Sweden)

    Liudan Jiao

    2016-09-01

    Full Text Available The rapid urbanization process has brought problems to China, such as traffic congestion, air pollution, water pollution and resources scarcity. Sustainable urbanization is commonly appreciated as an effective way to promote the sustainable development. The proper understanding of the sustainable urbanization performance is critical to provide governments with support in making urban development strategies and policies for guiding the sustainable development. This paper utilizes the method of Structural equation modeling (SEM to establish an assessment model for measuring sustainable urbanization performance. Four unobserved endogenous variables, economic variable, social variable, environment variable and resource variable, and 21 observed endogenous variables comprise the SEM model. A case study of the 31 provinces in China demonstrates the validity of the SEM model and the analysis results indicated that the assessment model could help make more effective policies and strategies for improving urban sustainability by recognizing the statue of sustainable urbanization.

  10. Simple models for studying complex spatiotemporal patterns of animal behavior

    Science.gov (United States)

    Tyutyunov, Yuri V.; Titova, Lyudmila I.

    2017-06-01

    Minimal mathematical models able to explain complex patterns of animal behavior are essential parts of simulation systems describing large-scale spatiotemporal dynamics of trophic communities, particularly those with wide-ranging species, such as occur in pelagic environments. We present results obtained with three different modelling approaches: (i) an individual-based model of animal spatial behavior; (ii) a continuous taxis-diffusion-reaction system of partial-difference equations; (iii) a 'hybrid' approach combining the individual-based algorithm of organism movements with explicit description of decay and diffusion of the movement stimuli. Though the models are based on extremely simple rules, they all allow description of spatial movements of animals in a predator-prey system within a closed habitat, reproducing some typical patterns of the pursuit-evasion behavior observed in natural populations. In all three models, at each spatial position the animal movements are determined by local conditions only, so the pattern of collective behavior emerges due to self-organization. The movement velocities of animals are proportional to the density gradients of specific cues emitted by individuals of the antagonistic species (pheromones, exometabolites or mechanical waves of the media, e.g., sound). These cues play a role of taxis stimuli: prey attract predators, while predators repel prey. Depending on the nature and the properties of the movement stimulus we propose using either a simplified individual-based model, a continuous taxis pursuit-evasion system, or a little more detailed 'hybrid' approach that combines simulation of the individual movements with the continuous model describing diffusion and decay of the stimuli in an explicit way. These can be used to improve movement models for many species, including large marine predators.

  11. Remote Sensing Characterization of the Urban Landscape for Improvement of Air Quality Modeling

    Science.gov (United States)

    Quattrochi, Dale A.; Estes, Maurice G., Jr.; Khan, Maudood

    2005-01-01

    The urban landscape is inherently complex and this complexity is not adequately captured in air quality models, particularly the Community Multiscale Air Quality (CMAQ) model that is used to assess whether urban areas are in attainment of EPA air quality standards, primarily for ground level ozone. This inadequacy of the CMAQ model to sufficiently respond to the heterogeneous nature of the urban landscape can impact how well the model predicts ozone pollutant levels over metropolitan areas and ultimately, whether cities exceed EPA ozone air quality standards. We are exploring the utility of high-resolution remote sensing data and urban growth projections as improved inputs to the meteorology component of the CMAQ model focusing on the Atlanta, Georgia metropolitan area as a case study. These growth projections include "business as usual" and "smart growth" scenarios out to 2030. The growth projections illustrate the effects of employing urban heat island mitigation strategies, such as increasing tree canopy and albedo across the Atlanta metro area, in moderating ground-level ozone and air temperature, compared to "business as usual" simulations in which heat island mitigation strategies are not applied. The National Land Cover Dataset at 30m resolution is being used as the land use/land cover input and aggregated to the 4km scale for the MM5 mesoscale meteorological model and the (CMAQ) modeling schemes. Use of these data has been found to better characterize low densityhburban development as compared with USGS 1 km land use/land cover data that have traditionally been used in modeling. Air quality prediction for fiture scenarios to 2030 is being facilitated by land use projections using a spatial growth model. Land use projections were developed using the 2030 Regional Transportation Plan developed by the Atlanta Regional Commission, the regional planning agency for the area. This allows the state Environmental Protection agency to evaluate how these

  12. Automatic 3D modeling of the urban landscape

    NARCIS (Netherlands)

    Esteban, I.; Dijk, J.; Groen, F.

    2010-01-01

    In this paper we present a fully automatic system for building 3D models of urban areas at the street level. We propose a novel approach for the accurate estimation of the scale consistent camera pose given two previous images. We employ a new method for global optimization and use a novel sampling

  13. Violence and stress at work in the transport sector

    OpenAIRE

    Essenberg, Bert

    2003-01-01

    Examines trends in occupational stress and violence experienced by rural and urban transport workers, railway employees, taxi drivers, road freight drivers, and air traffic controllers. Does not cover violence on board civil aircraft.

  14. Land Cover Mapping Analysis and Urban Growth Modelling Using Remote Sensing Techniques in Greater Cairo Region—Egypt

    Directory of Open Access Journals (Sweden)

    Yasmine Megahed

    2015-09-01

    Full Text Available This study modeled the urban growth in the Greater Cairo Region (GCR, one of the fastest growing mega cities in the world, using remote sensing data and ancillary data. Three land use land cover (LULC maps (1984, 2003 and 2014 were produced from satellite images by using Support Vector Machines (SVM. Then, land cover changes were detected by applying a high level mapping technique that combines binary maps (change/no-change and post classification comparison technique. The spatial and temporal urban growth patterns were analyzed using selected statistical metrics developed in the FRAGSTATS software. Major transitions to urban were modeled to predict the future scenarios for year 2025 using Land Change Modeler (LCM embedded in the IDRISI software. The model results, after validation, indicated that 14% of the vegetation and 4% of the desert in 2014 will be urbanized in 2025. The urban areas within a 5-km buffer around: the Great Pyramids, Islamic Cairo and Al-Baron Palace were calculated, highlighting an intense urbanization especially around the Pyramids; 28% in 2014 up to 40% in 2025. Knowing the current and estimated urbanization situation in GCR will help decision makers to adjust and develop new plans to achieve a sustainable development of urban areas and to protect the historical locations.

  15. Hourly Water Quality Dynamics in Rivers Downstream of Urban Areas: Quantifying Seasonal Variation and Modelling Impacts of Urban Growth

    Science.gov (United States)

    Hutchins, M.; McGrane, S. J.; Miller, J. D.; Hitt, O.; Bowes, M.

    2016-12-01

    Continuous monitoring of water flows and quality is invaluable in improving understanding of the influence of urban areas on river health. When used to inform predictive modelling, insights can be gained as to how urban growth may affect the chemical and biological quality of rivers as they flow downstream into larger waterbodies. Water flow and quality monitoring in two urbanising sub-catchments (long term flow records are available, but particular focus is given to monitoring of an extended set of sites during prolonged winter rainfall. In the Ray sub-catchment streams were monitored in which urban cover varied across a range of 7-78%. A rural-urban gradient in DO was apparent in the low flow period prior to the storms. Transient low DO (works (STW). In this respect temperature- and respiration-driven DO sags in summer were at least if not more severe than those driven by the winter storms. Likewise, although winter storm NH4 concentrations violated EU legislation downstream of the STW, they were lower than summer concentrations in pollutant flushes following dry spells. In contrast the predominant phenomenon affecting water quality in the Cut during the storms was dilution. Here, a river water quality model was calibrated and applied over the course of a year to capture the importance of periphyton photosynthesis and respiration cycles in determining water quality and to predict the influence of hypothetical urban growth on downstream river health. The periods monitored intensively, dry spells followed by prolonged rainfall, represent: (i) marked changes in conditions likely to become more prevalent in future, (ii) situations under which water quality in urban areas is likely to be particularly vulnerable, being influenced for example by first flush effects followed by capacity exceedance at STW. Despite this, whilst being somewhat long lasting in places, impacts on DO were not severe.

  16. Data-driven urban drainage analysis : An alternative to hydrodynamic models?

    NARCIS (Netherlands)

    ten Veldhuis, J.A.E.; Tait, S.J.

    2011-01-01

    In the past, there has been an emphasis on the use of hydrodynamic models as a tool for urban drainage analysis. Limited availability of monitoring data and the perceived more limited resource requirements of models led to a preference for this approach. The last decade has seen a gradual

  17. Urban traffic noise assessment by combining measurement and model results

    NARCIS (Netherlands)

    Eerden, F.J.M. van der; Graafland, F.; Wessels, P.W.; Basten, T.G.H.

    2013-01-01

    A model based monitoring system is applied on a local scale in an urban area to obtain a better understanding of the traffic noise situation. The system consists of a scalable sensor network and an engineering model. A better understanding is needed to take appropriate and cost efficient measures,

  18. Urban nonpoint source pollution buildup and washoff models for simulating storm runoff quality in the Los Angeles County.

    Science.gov (United States)

    Wang, Long; Wei, Jiahua; Huang, Yuefei; Wang, Guangqian; Maqsood, Imran

    2011-07-01

    Many urban nonpoint source pollution models utilize pollutant buildup and washoff functions to simulate storm runoff quality of urban catchments. In this paper, two urban pollutant washoff load models are derived using pollutant buildup and washoff functions. The first model assumes that there is no residual pollutant after a storm event while the second one assumes that there is always residual pollutant after each storm event. The developed models are calibrated and verified with observed data from an urban catchment in the Los Angeles County. The application results show that the developed model with consideration of residual pollutant is more capable of simulating nonpoint source pollution from urban storm runoff than that without consideration of residual pollutant. For the study area, residual pollutant should be considered in pollutant buildup and washoff functions for simulating urban nonpoint source pollution when the total runoff volume is less than 30 mm. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. Monitoring and Modeling of Spatiotemporal Urban Expansion and Land-Use/Land-Cover Change Using Integrated Markov Chain Cellular Automata Model

    Directory of Open Access Journals (Sweden)

    Bhagawat Rimal

    2017-09-01

    Full Text Available Spatial–temporal analysis of land-use/land-cover (LULC change as well as the monitoring and modeling of urban expansion are essential for the planning and management of urban environments. Such environments reflect the economic conditions and quality of life of the individual country. Urbanization is generally influenced by national laws, plans and policies and by power, politics and poor governance in many less-developed countries. Remote sensing tools play a vital role in monitoring LULC change and measuring the rate of urbanization at both the local and global levels. The current study evaluated the LULC changes and urban expansion of Jhapa district of Nepal. The spatial–temporal dynamics of LULC were identified using six time-series atmospherically-corrected surface reflectance Landsat images from 1989 to 2016. A hybrid cellular automata Markov chain (CA–Markov model was used to simulate future urbanization by 2026 and 2036. The analysis shows that the urban area has increased markedly and is expected to continue to grow rapidly in the future, whereas the area for agriculture has decreased. Meanwhile, forest and shrub areas have remained almost constant. Seasonal rainfall and flooding routinely cause predictable transformation of sand, water bodies and cultivated land from one type to another. The results suggest that the use of Landsat time-series archive images and the CA–Markov model are the best options for long-term spatiotemporal analysis and achieving an acceptable level of prediction accuracy. Furthermore, understanding the relationship between the spatiotemporal dynamics of urbanization and LULC change and simulating future landscape change is essential, as they are closely interlinked. These scientific findings of past, present and future land-cover scenarios of the study area will assist planners/decision-makers to formulate sustainable urban development and environmental protection plans and will remain a scientific asset

  20. A selfsimilar behavior of the urban structure in the spatially inhomogeneous model

    Science.gov (United States)

    Echkina, E. Y.; Inovenkov, O. I.; Kostomarov, D. P.

    2006-03-01

    At present there is a strong tendency to use new methods for the description of the regional and spatial economy. In increasing frequency we consider that any economic activity is spatially dependent. The problem of the evolution of internal urban formation can be described with the exact supposition. So that is why we use partial derivative equations set with the appropriate boundary and initial conditions for the solving the problem of the urban evolution. Here we describe the model of urban population's density modification taking into account a modification of the housing quality. A program has been created which realizes difference method of mixed problem solution for population's density. For the wide class of coefficients it has been shown that the problem's solution “quickly forgets” the parts of the initial conditions and comes out to the intermediate asymptotic form, which nature depends only on the problem's operator. Actually it means that the urban structure does not depend on external circumstances and is formed by the internal structure of the model.

  1. Modeling Hydrologic Processes after Vegetation Restoration in an Urban Watershed with HEC-HMS

    Science.gov (United States)

    Stevenson, K.; Kinoshita, A. M.

    2017-12-01

    The San Diego River Watershed in California (USA) is highly urbanized, where stream channel geomorphology are directly affected by anthropogenic disturbances. Flooding and water quality concerns have led to an increased interest in improving the condition of urban waterways. Alvarado Creek, a 1200-meter section of a tributary to the San Diego River will be used as a case study to understand the degree to which restoration efforts reduce the impacts of climate change and anthropogenic activities on hydrologic processes and water quality in urban stream ecosystems. In 2016, non-native vegetation (i.e. Washingtonia spp. (fan palm), Phoenix canariensis (Canary Island palm)) and approximately 7257 kilograms of refuse were removed from the study reach. This research develops the United States Army Corp of Engineers Hydrologic Engineering Center's Hydraulic Modeling System (USACE HEC-HMS) using field-based data to model and predict the short- and long-term impacts of restoration on geomorphic and hydrologic processes. Observations include cross-sectional area, grain-size distributions, water quality, and continuous measurements of streamflow, temperature, and precipitation. Baseline and design storms are simulated before and after restoration. The model will be calibrated and validated using field observations. The design storms represent statistical likelihoods of storms occurrences, and the pre- and post-restoration hydrologic responses will be compared to evaluate the impact of vegetation and waste removal on runoff processes. Ultimately model parameters will be transferred to other urban creeks in San Diego that may potentially undergo restoration. Modeling will be used to learn about the response trajectory of rainfall-runoff processes following restoration efforts in urban streams and guide future management and restoration activities.

  2. Business models in urban farming: A comparative analysis of case studies from Spain, Italy and Germany

    Directory of Open Access Journals (Sweden)

    Pölling Bernd

    2017-09-01

    Full Text Available The “Urban Agriculture Europe” EU COST-Action (2012–2016 has shown that the complexity of urban agriculture (UA is hardly compressible into classic business management models and has proposed new management models, such as the Business Model Canvas (BMC. Business models of UA have to be different from rural ones. In particular, factors such as differentiation and diversification, but also low cost-oriented specialisation, are characteristic and necessary business models for UA to stay profitable in the long term under challenging city conditions. This paper aims to highlight how farm enterprises have to adjust to urban conditions by stepping into appropriate business models aiming to stay competitive and profitable, and how the BMC is useful to analyse their organisation and performance, both economically and socially. The paper offers an inter-regional analysis of UA enterprises located in Spain, Italy, and Germany, which are further subdivided into: local food, leisure, educational, social, therapeutic, agri-environmental, cultural heritage and experimental farms. The analysis demonstrates that UA is differentially adjusted to specific urban conditions and that the BMC is useful for analysing urban farming. Heterogeneous local food farms and the integration of local and organic food production in social farming business models are most frequent in our case studies.

  3. The Fusion Model of Intelligent Transportation Systems Based on the Urban Traffic Ontology

    Science.gov (United States)

    Yang, Wang-Dong; Wang, Tao

    On these issues unified representation of urban transport information using urban transport ontology, it defines the statute and the algebraic operations of semantic fusion in ontology level in order to achieve the fusion of urban traffic information in the semantic completeness and consistency. Thus this paper takes advantage of the semantic completeness of the ontology to build urban traffic ontology model with which we resolve the problems as ontology mergence and equivalence verification in semantic fusion of traffic information integration. Information integration in urban transport can increase the function of semantic fusion, and reduce the amount of data integration of urban traffic information as well enhance the efficiency and integrity of traffic information query for the help, through the practical application of intelligent traffic information integration platform of Changde city, the paper has practically proved that the semantic fusion based on ontology increases the effect and efficiency of the urban traffic information integration, reduces the storage quantity, and improve query efficiency and information completeness.

  4. Land-Use Regression Modelling of Intra-Urban Air Pollution Variation in China: Current Status and Future Needs

    Directory of Open Access Journals (Sweden)

    Baihuiqian He

    2018-04-01

    Full Text Available Rapid urbanization in China is leading to substantial adverse air quality issues, particularly for NO2 and particulate matter (PM. Land-use regression (LUR models are now being applied to simulate pollutant concentrations with high spatial resolution in Chinese urban areas. However, Chinese urban areas differ from those in Europe and North America, for example in respect of population density, urban morphology and pollutant emissions densities, so it is timely to assess current LUR studies in China to highlight current challenges and identify future needs. Details of twenty-four recent LUR models for NO2 and PM2.5/PM10 (particles with aerodynamic diameters <2.5 µm and <10 µm are tabulated and reviewed as the basis for discussion in this paper. We highlight that LUR modelling in China is currently constrained by a scarcity of input data, especially air pollution monitoring data. There is an urgent need for accessible archives of quality-assured measurement data and for higher spatial resolution proxy data for urban emissions, particularly in respect of traffic-related variables. The rapidly evolving nature of the Chinese urban landscape makes maintaining up-to-date land-use and urban morphology datasets a challenge. We also highlight the importance for Chinese LUR models to be subject to appropriate validation statistics. Integration of LUR with portable monitor data, remote sensing, and dispersion modelling has the potential to enhance derivation of urban pollution maps.

  5. Urban Growth Modeling Using AN Artificial Neural Network a Case Study of Sanandaj City, Iran

    Science.gov (United States)

    Mohammady, S.; Delavar, M. R.; Pahlavani, P.

    2014-10-01

    Land use activity is a major issue and challenge for town and country planners. Modelling and managing urban growth is a complex problem. Cities are now recognized as complex, non-linear and dynamic process systems. The design of a system that can handle these complexities is a challenging prospect. Local governments that implement urban growth models need to estimate the amount of urban land required in the future given anticipated growth of housing, business, recreation and other urban uses within the boundary. There are so many negative implications related with the type of inappropriate urban development such as increased traffic and demand for mobility, reduced landscape attractively, land use fragmentation, loss of biodiversity and alterations of the hydrological cycle. The aim of this study is to use the Artificial Neural Network (ANN) to make a powerful tool for simulating urban growth patterns. Our study area is Sanandaj city located in the west of Iran. Landsat imageries acquired at 2000 and 2006 are used. Dataset were used include distance to principle roads, distance to residential areas, elevation, slope, distance to green spaces and distance to region centers. In this study an appropriate methodology for urban growth modelling using satellite remotely sensed data is presented and evaluated. Percent Correct Match (PCM) and Figure of Merit were used to evaluate ANN results.

  6. URBAN GROWTH MODELING USING AN ARTIFICIAL NEURAL NETWORK A CASE STUDY OF SANANDAJ CITY, IRAN

    Directory of Open Access Journals (Sweden)

    S. Mohammady

    2014-10-01

    Full Text Available Land use activity is a major issue and challenge for town and country planners. Modelling and managing urban growth is a complex problem. Cities are now recognized as complex, non-linear and dynamic process systems. The design of a system that can handle these complexities is a challenging prospect. Local governments that implement urban growth models need to estimate the amount of urban land required in the future given anticipated growth of housing, business, recreation and other urban uses within the boundary. There are so many negative implications related with the type of inappropriate urban development such as increased traffic and demand for mobility, reduced landscape attractively, land use fragmentation, loss of biodiversity and alterations of the hydrological cycle. The aim of this study is to use the Artificial Neural Network (ANN to make a powerful tool for simulating urban growth patterns. Our study area is Sanandaj city located in the west of Iran. Landsat imageries acquired at 2000 and 2006 are used. Dataset were used include distance to principle roads, distance to residential areas, elevation, slope, distance to green spaces and distance to region centers. In this study an appropriate methodology for urban growth modelling using satellite remotely sensed data is presented and evaluated. Percent Correct Match (PCM and Figure of Merit were used to evaluate ANN results.

  7. Planning the public transport system in Mucat (Oman)

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Jimenez, J.; Hitado Hernandez, E.; Sanz Pecharroman, C.

    2016-07-01

    In Muscat, the capital of Oman with over one million inhabitants, urban public transport practically does not exist and the use of private cars is dramatically increasing. As a result, accident rates and traffic congestion, two particularly pressing concerns in the urban area of the capital, have both risen. This situation has focused the concern of public administrations and has led to the urgent need of developing a Public Transport System in the city. In order to develop this system in an integrated manner, the plan proposes to unify and organize regulation and management of public transport by creating a public transport authority, headed by the Ministry of Transport and with a very strong involvement of Muscat Municipality. By 2015 only two urban bus lines operate in Muscat, covering a small area of the city–Wadi Adei, Wadi Kabir and Ruwi. Therefore, the plan adopts a conservative approach by proposing the implementation of a comprehensive urban bus network –composed by trunk and feeder lines adapted to the low density of the city- before establishing other high capacity solutions, such as BRT or LRT. A key element of the system is the number of 13,400 taxis and microbuses that represent the only alternative to the 317,000 cars of Muscat. The plan suggests the reorganization and further regulation of the sector to achieve the professionalization of the taxi services and the migration of existing users, part of them to the professionalised taxi services and the other part to the implemented public transport services. (Author)

  8. Measuring the impact of urban policies on transportation energy saving using a land use-transport model

    Directory of Open Access Journals (Sweden)

    Masanobu Kii

    2014-03-01

    This study demonstrates the applicability of a land-use transport model to the assessment of urban policies for building smart communities. First, we outline a model that explicitly formulates the actors' location-related decisions and travel behavior. Second, we apply this model to two urban policies – road pricing and land-use regulation – to assess their long-term impact on energy saving and sustainability using the case of a simplified synthetic city. Our study verifies that, under assumed conditions, the model has the capacity to assess urban policies on energy use and sustainability in a consistent fashion.

  9. Exposure level of carbon monoxide and respirable suspended particulate in public transportation modes while commuting in urban area of Guangzhou, China

    Science.gov (United States)

    Chan, L. Y.; Lau, W. L.; Zou, S. C.; Cao, Z. X.; Lai, S. C.

    This study examined commuter exposure to respirable suspended particulate (PM 10 and PM 2.5) and carbon monoxide (CO) in public transportation modes in Guangzhou, China. During the sampling period, a total of 80 CO, 80 PM 10 and 56 PM 2.5 samples were conducted in four popular commuting modes (subway, air-conditioned bus, non-air-conditioned bus and taxi) while running in typical urban routes. The results show that the PM 10 as well as CO level is greatly influenced by the mode of transport. The highest mean PM 10 and CO level was obtained in a non-air-conditioned bus (203 μg m -3) and in an air-conditioned taxi (28.7 ppm) , respectively. Noticeably, the exposure levels in subway are lower than those in the roadway transports. The ventilation condition of the transport is also a crucial factor affecting the in-vehicle level. There was statistically significant difference of PM10 (ptransports, which provide service at regular intervals regardless of the time of day. The PM 2.5 inter-microenvironment variation is similar to the pattern of PM 10. The PM 2.5 to PM 10 ratio in the transports was high, ranging from 76% to 83%. The poor vehicle emission controls, poor vehicle maintenance, plus the slow moving traffic condition with frequent stops are believed to be the major causes of high in-vehicle levels in some public commuting trips.

  10. The Spatio-Temporal Modeling of Urban Growth Using Remote Sensing and Intelligent Algorithms, Case of Mahabad, Iran

    Directory of Open Access Journals (Sweden)

    Alì Soltani

    2013-06-01

    Full Text Available The simulation of urban growth can be considered as a useful way for analyzing the complex process of urban physical evolution. The aim of this study is to model and simulate the complex patterns of land use change by utilizing remote sensing and artificial intelligence techniques in the fast growing city of Mahabad, north-west of Iran which encountered with several environmental subsequences. The key subject is how to allocate optimized weight into effective parameters upon urban growth and subsequently achieving an improved simulation. Artificial Neural Networks (ANN algorithm was used to allocate the weight via an iteration approach. In this way, weight allocation was carried out by the ANN training accomplishing through time-series satellite images representing urban growth process. Cellular Automata (CA was used as the principal motor of the model and then ANN applied to find suitable scale of parameters and relations between potential factors affecting urban growth. The general accuracy of the suggested model and obtained Fuzzy Kappa Coefficient confirms achieving better results than classic CA models in simulating nonlinear urban evolution process.

  11. Modeling Urban Growth Spatial Dynamics: Case studies of Addis Ababa and Dar es Salaam

    Science.gov (United States)

    Buchta, Katja; Abo El Wafa, Hany; Printz, Andreas; Pauleit, Stephan

    2013-04-01

    Rapid urbanization, and consequently, the dramatic spatial expansion of mostly informal urban areas increases the vulnerability of African cities to the effects of climate change such as sea level rise, more frequent flooding, droughts and heat waves. The EU FP 7 funded project CLUVA (Climate Change and Urban Vulnerability in Africa, www.cluva.eu) aims to develop strategies for minimizing the risks of natural hazards caused by climate change and to improve the coping capacity of African cities. Green infrastructure may play a particular role in climate change adaptation by providing ecosystem services for flood protection, stormwater retention, heat island moderation and provision of food and fuel wood. In this context, a major challenge is to gain a better understanding of the spatial and temporal dynamics of the cities and how these impact on green infrastructure and hence their vulnerability. Urban growth scenarios for two African cities, namely Addis Ababa, Ethiopia and Dar es Salaam, Tanzania, were developed based on a characterization of their urban morphology. A population growth driven - GIS based - disaggregation modeling approach was applied. Major impact factors influencing the urban dynamics were identified both from literature and interviews with local experts. Location based factors including proximity to road infrastructure and accessibility, and environmental factors including slope, surface and flood risk areas showed a particular impact on urban growth patterns. In Addis Ababa and Dar es Salaam, population density scenarios were modeled comparing two housing development strategies. Results showed that a densification scenario significantly decreases the loss of agricultural and green areas such as forests, bushland and sports grounds. In Dar es Salaam, the scenario of planned new settlements with a population density of max. 350 persons per hectare would lead until 2025 to a loss of agricultural land (-10.1%) and green areas (-6.6%). On the other

  12. The Power of Micro Urban Structures, Theory of EEPGC - the Micro Urban Energy Distribution Model as a Planning Tool for Sustainable City Development

    Directory of Open Access Journals (Sweden)

    Tkáč Štefan

    2015-11-01

    Full Text Available To achieve the smart growth and equitable development in the region, urban planners should consider also lateral energies represented by the energy urban models like further proposed EEPGC focused on energy distribution via connections among micro-urban structures, their onsite renewable resources and the perception of micro-urban structures as decentralized energy carriers based on pre industrialized era. These structures are still variously bound when part of greater patterns. After the industrial revolution the main traded goods became energy in its various forms. The EEPGC is focused on sustainable energy transportation distances between the villages and the city, described by the virtual “energy circles”. This more human scale urbanization, boost the economy in micro-urban areas, rising along with clean energy available in situ that surely gives a different perspective to human quality of life in contrast to overcrowded multicultural mega-urban structures facing generations of problems and struggling to survive as a whole.

  13. The Power of Micro Urban Structures, Theory of EEPGC - the Micro Urban Energy Distribution Model as a Planning Tool for Sustainable City Development

    Science.gov (United States)

    Tkáč, Štefan

    2015-11-01

    To achieve the smart growth and equitable development in the region, urban planners should consider also lateral energies represented by the energy urban models like further proposed EEPGC focused on energy distribution via connections among micro-urban structures, their onsite renewable resources and the perception of micro-urban structures as decentralized energy carriers based on pre industrialized era. These structures are still variously bound when part of greater patterns. After the industrial revolution the main traded goods became energy in its various forms. The EEPGC is focused on sustainable energy transportation distances between the villages and the city, described by the virtual "energy circles". This more human scale urbanization, boost the economy in micro-urban areas, rising along with clean energy available in situ that surely gives a different perspective to human quality of life in contrast to overcrowded multicultural mega-urban structures facing generations of problems and struggling to survive as a whole.

  14. A Two-Stage Queue Model to Optimize Layout of Urban Drainage System considering Extreme Rainstorms

    Directory of Open Access Journals (Sweden)

    Xinhua He

    2017-01-01

    Full Text Available Extreme rainstorm is a main factor to cause urban floods when urban drainage system cannot discharge stormwater successfully. This paper investigates distribution feature of rainstorms and draining process of urban drainage systems and uses a two-stage single-counter queue method M/M/1→M/D/1 to model urban drainage system. The model emphasizes randomness of extreme rainstorms, fuzziness of draining process, and construction and operation cost of drainage system. Its two objectives are total cost of construction and operation and overall sojourn time of stormwater. An improved genetic algorithm is redesigned to solve this complex nondeterministic problem, which incorporates with stochastic and fuzzy characteristics in whole drainage process. A numerical example in Shanghai illustrates how to implement the model, and comparisons with alternative algorithms show its performance in computational flexibility and efficiency. Discussions on sensitivity of four main parameters, that is, quantity of pump stations, drainage pipe diameter, rainstorm precipitation intensity, and confidence levels, are also presented to provide guidance for designing urban drainage system.

  15. Modeling and assessment of hydrological changes in a developing urban catchment

    OpenAIRE

    Guan, M; Sillanpää, N; Koivusalo, H

    2015-01-01

    Urbanization strongly changes natural catchment by increasing impervious coverage and by creating a need for efficient drainage systems. Such land cover changes lead to more rapid hydrological response to storms and change distribution of peak and low flows. This study aims to explore and assess how gradual hydrological changes occur during urban development from rural area to a medium-density residential catchment. The Stormwater Management Model (SWMM) is utilized to simulate a series of sc...

  16. Optimising the anaerobic co-digestion of urban organic waste using dynamic bioconversion mathematical modelling

    DEFF Research Database (Denmark)

    Fitamo, Temesgen Mathewos; Boldrin, Alessio; Dorini, G.

    2016-01-01

    Mathematical anaerobic bioconversion models are often used as a convenient way to simulate the conversion of organic materials to biogas. The aim of the study was to apply a mathematical model for simulating the anaerobic co-digestion of various types of urban organic waste, in order to develop...... in a continuously stirred tank reactor. The model's outputs were validated with experimental results obtained in thermophilic conditions, with mixed sludge as a single substrate and urban organic waste as a co-substrate at hydraulic retention times of 30, 20, 15 and 10 days. The predicted performance parameter...... (methane productivity and yield) and operational parameter (concentration of ammonia and volatile fatty acid) values were reasonable and displayed good correlation and accuracy. The model was later applied to identify optimal scenarios for an urban organic waste co-digestion process. The simulation...

  17. Integrating local urban climate modelling and mobile sensor data for personal exposure assessments in the context of urban heat island effect

    Science.gov (United States)

    Ueberham, Maximilian; Hertel, Daniel; Schlink, Uwe

    2017-04-01

    Deeper knowledge about urban climate conditions is getting more important in the context of climate change, urban population growth, urban compaction and continued surface sealing. Especially the urban heat island effect (UHI) is one of the most significant human induced alterations of Earth's surface climate. According to this the appearance frequency of heat waves in cities will increase with deep impacts on personal thermal comfort, human health and local residential quality of citizens. UHI can be very heterogenic within a city and research needs to focus more on the neighborhood scale perspective to get further insights about the heat burden of individuals. However, up to now, few is known about local thermal environmental variances and personal exposure loads. To monitor these processes and the impact on individuals, improved monitoring approaches are crucial, complementing data recorded at conventional fixed stations. Therefore we emphasize the importance of micro-meteorological modelling and mobile measurements to shed new light on the nexus of urban human-climate interactions. Contributing to this research we jointly present the approaches of our two PhD-projects. Firstly we illustrate on the basis of an example site, how local thermal conditions in an urban district can be simulated and predicted by a micro-meteorological model. Secondly we highlight the potentials of personal exposure measurements based on an evaluation of mobile micro-sensing devices (MSDs) and analyze and explain differences between model predictions and mobile records. For the examination of local thermal conditions we calculated ENVI-met simulations within the "Bayerischer Bahnhof" quarter in Leipzig (Saxony, Germany; 51°20', 12°22'). To accomplish the maximum temperature contrasts within the diverse built-up structures we chose a hot summer day (25 Aug 2016) under autochthonous weather conditions. From these simulations we analyzed a UHI effect between the model core (urban area

  18. Coupling Modelling of Urban Development and Flood Risk – An Attempt for a Combined Software Framework

    DEFF Research Database (Denmark)

    Löwe, Roland; Sto Domingo, Nina; Urich, Christian

    2015-01-01

    to use the results of the hydraulic simulation to condition DANCE4WATER and to account for flood risk in the simulated urban development. In an Australian case study, we demonstrate that future flood risk can be significantly reduced while maintaining the overall speed of urban development.......We have developed a setup that couples the urban development model DANCE4WATER with the 1D-2D hydraulic model MIKE FLOOD. The setup makes it possible to assess the impact of urban development and infrastructural change scenarios on flood risk in an automated manner. In addition, it permits us...

  19. Modeling Methodologies for Representing Urban Cultural Geographies in Stability Operations

    National Research Council Canada - National Science Library

    Ferris, Todd P

    2008-01-01

    ... 2.0.0, in an effort to provide modeling methodologies for a single simulation tool capable of exploring the complex world of urban cultural geographies undergoing Stability Operations in an irregular warfare (IW) environment...

  20. Sensing Urban Land-Use Patterns by Integrating Google Tensorflow and Scene-Classification Models

    Science.gov (United States)

    Yao, Y.; Liang, H.; Li, X.; Zhang, J.; He, J.

    2017-09-01

    With the rapid progress of China's urbanization, research on the automatic detection of land-use patterns in Chinese cities is of substantial importance. Deep learning is an effective method to extract image features. To take advantage of the deep-learning method in detecting urban land-use patterns, we applied a transfer-learning-based remote-sensing image approach to extract and classify features. Using the Google Tensorflow framework, a powerful convolution neural network (CNN) library was created. First, the transferred model was previously trained on ImageNet, one of the largest object-image data sets, to fully develop the model's ability to generate feature vectors of standard remote-sensing land-cover data sets (UC Merced and WHU-SIRI). Then, a random-forest-based classifier was constructed and trained on these generated vectors to classify the actual urban land-use pattern on the scale of traffic analysis zones (TAZs). To avoid the multi-scale effect of remote-sensing imagery, a large random patch (LRP) method was used. The proposed method could efficiently obtain acceptable accuracy (OA = 0.794, Kappa = 0.737) for the study area. In addition, the results show that the proposed method can effectively overcome the multi-scale effect that occurs in urban land-use classification at the irregular land-parcel level. The proposed method can help planners monitor dynamic urban land use and evaluate the impact of urban-planning schemes.

  1. Research on the Model of E-commerce of China’s Urban Informatization Community

    Directory of Open Access Journals (Sweden)

    Yu Han

    2014-02-01

    Full Text Available Urban informatization e-commerce is a business model of the combination of e-commerce operators and organizational forms of community property management, and the import of people management and property management into e-commerce. This paper analyzes the current situation of Chinese urban community e-commerce and informatization community building. It puts forward the model of community e-commerce based on informatization, and its feasibility was verified by PIECE method. Finally, focusing on the application, the model of community e-commerce based on informatization community is analyzed in detail from the perspective of the role and value, supply chain and collaborative management works. Information services are most likely to succeed in the entry point of e-commerce. The study has shown that the establishment of community e-commerce on the basis of urban informatization community can be regarded as a solution of e-commerce development.

  2. Evaluation of Urban air quality models for regulatory use: Refinement of an approach

    International Nuclear Information System (INIS)

    Downton, M.W.; Dennis, R.L.

    1985-01-01

    Statistical measures for evaluating the performance of urban air quality models have recently been strongly recommended by several investigators. Problems that were encountered in the use of recommended performance measures in an evaluation of three versions of an urban photochemical model are described. The example demonstrates the importance of designing an evaluation to take into account the way in which the model will be used in regulatory practice, and then choosing performance measures on the basis of that design. The evaluation illustrates some limitations and possible pitfalls in the use and interpretation of statistical measures of model performance. Drawing on this experience, a procedure for evaluation of air quality models for regulatory use is suggested

  3. Coupling impervious surface rate derived from satellite remote sensing with distributed hydrological model for highly urbanized watershed flood forecasting

    Science.gov (United States)

    Dong, L.

    2017-12-01

    Abstract: The original urban surface structure changed a lot because of the rapid development of urbanization. Impermeable area has increased a lot. It causes great pressure for city flood control and drainage. Songmushan reservoir basin with high degree of urbanization is taken for an example. Pixel from Landsat is decomposed by Linear spectral mixture model and the proportion of urban area in it is considered as impervious rate. Based on impervious rate data before and after urbanization, an physically based distributed hydrological model, Liuxihe Model, is used to simulate the process of hydrology. The research shows that the performance of the flood forecasting of high urbanization area carried out with Liuxihe Model is perfect and can meet the requirement of the accuracy of city flood control and drainage. The increase of impervious area causes conflux speed more quickly and peak flow to be increased. It also makes the time of peak flow advance and the runoff coefficient increase. Key words: Liuxihe Model; Impervious rate; City flood control and drainage; Urbanization; Songmushan reservoir basin

  4. Analysis of Settlement Expansion and Urban Growth Modelling Using Geoinformation for Assessing Potential Impacts of Urbanization on Climate in Abuja City, Nigeria

    Directory of Open Access Journals (Sweden)

    Mahmoud Ibrahim Mahmoud

    2016-03-01

    Full Text Available This study analyzed the spatiotemporal pattern of settlement expansion in Abuja, Nigeria, one of West Africa’s fastest developing cities, using geoinformation and ancillary datasets. Three epochs of Land-use Land-cover (LULC maps for 1986, 2001 and 2014 were derived from Landsat images using support vector machines (SVM. Accuracy assessment (AA of the LULC maps based on the pixel count resulted in overall accuracy of 82%, 92% and 92%, while the AA derived from the error adjusted area (EAA method stood at 69%, 91% and 91% for 1986, 2001 and 2014, respectively. Two major techniques for detecting changes in the LULC epochs involved the use of binary maps as well as a post-classification comparison approach. Quantitative spatiotemporal analysis was conducted to detect LULC changes with specific focus on the settlement development pattern of Abuja, the federal capital city (FCC of Nigeria. Logical transitions to the urban category were modelled for predicting future scenarios for the year 2050 using the embedded land change modeler (LCM in the IDRISI package. Based on the EAA, the result showed that urban areas increased by more than 11% between 1986 and 2001. In contrast, this value rose to 17% between 2001 and 2014. The LCM model projected LULC changes that showed a growing trend in settlement expansion, which might take over allotted spaces for green areas and agricultural land if stringent development policies and enforcement measures are not implemented. In conclusion, integrating geospatial technologies with ancillary datasets offered improved understanding of how urbanization processes such as increased imperviousness of such a magnitude could influence the urban microclimate through the alteration of natural land surface temperature. Urban expansion could also lead to increased surface runoff as well as changes in drainage geography leading to urban floods.

  5. Validation of a Fast-Response Urban Micrometeorological Model to Assess the Performance of Urban Heat Island Mitigation Strategies

    Science.gov (United States)

    Nadeau, D.; Girard, P.; Overby, M.; Pardyjak, E.; Stoll, R., II; Willemsen, P.; Bailey, B.; Parlange, M. B.

    2015-12-01

    Urban heat islands (UHI) are a real threat in many cities worldwide and mitigation measures have become a central component of urban planning strategies. Even within a city, causes of UHI vary from one neighborhood to another, mostly due the spatial variability in surface thermal properties, building geometry, anthropogenic heat flux releases and vegetation cover. As a result, the performance of UHI mitigation measures also varies in space. Hence, there is a need to develop a tool to quantify the efficiency of UHI mitigation measures at the neighborhood scale. The objective of this ongoing study is to validate the fast-response micrometeorological model QUIC EnvSim (QES). This model can provide all information required for UHI studies with a fine spatial resolution (up to 0.5m) and short computation time. QES combines QUIC, a CFD-based wind solver and dispersion model, and EnvSim, composed of a radiation model, a land-surface model and a turbulent transport model. Here, high-resolution (1 m) simulations are run over a subset of the École Polytechnique Fédérale de Lausanne (EPFL) campus including complex buildings, various surfaces properties and vegetation. For nearly five months in 2006-07, a dense network of meteorological observations (92 weather stations over 0.1 km2) was deployed over the campus and these unique data are used here as a validation dataset. We present validation results for different test cases (e.g., sunny vs cloudy days, different incoming wind speeds and directions) and explore the effect of a few UHI mitigation strategies on the spatial distribution of near-surface air temperatures. Preliminary results suggest that QES may be a valuable tool in decision-making regarding adaptation of urban planning to UHI.

  6. Urban scale air quality modelling using detailed traffic emissions estimates

    Science.gov (United States)

    Borrego, C.; Amorim, J. H.; Tchepel, O.; Dias, D.; Rafael, S.; Sá, E.; Pimentel, C.; Fontes, T.; Fernandes, P.; Pereira, S. R.; Bandeira, J. M.; Coelho, M. C.

    2016-04-01

    The atmospheric dispersion of NOx and PM10 was simulated with a second generation Gaussian model over a medium-size south-European city. Microscopic traffic models calibrated with GPS data were used to derive typical driving cycles for each road link, while instantaneous emissions were estimated applying a combined Vehicle Specific Power/Co-operative Programme for Monitoring and Evaluation of the Long-range Transmission of Air Pollutants in Europe (VSP/EMEP) methodology. Site-specific background concentrations were estimated using time series analysis and a low-pass filter applied to local observations. Air quality modelling results are compared against measurements at two locations for a 1 week period. 78% of the results are within a factor of two of the observations for 1-h average concentrations, increasing to 94% for daily averages. Correlation significantly improves when background is added, with an average of 0.89 for the 24 h record. The results highlight the potential of detailed traffic and instantaneous exhaust emissions estimates, together with filtered urban background, to provide accurate input data to Gaussian models applied at the urban scale.

  7. A MODEL OF RURAL-URBAN CONFLICT IN DEVELOPING-COUNTRIES

    NARCIS (Netherlands)

    LENSINK, R

    1992-01-01

    A two-sector model for developing countries explicitly takes into account the influence of consumer goods rationing on the labour supply for market production and considers the effects of fiscal policy and exchange rate policy on the production of agricultural and urban goods. An increase in

  8. Brief introductory guide to agent-based modeling and an illustration from urban health research

    Directory of Open Access Journals (Sweden)

    Amy H. Auchincloss

    2015-11-01

    Full Text Available Abstract There is growing interest among urban health researchers in addressing complex problems using conceptual and computation models from the field of complex systems. Agent-based modeling (ABM is one computational modeling tool that has received a lot of interest. However, many researchers remain unfamiliar with developing and carrying out an ABM, hindering the understanding and application of it. This paper first presents a brief introductory guide to carrying out a simple agent-based model. Then, the method is illustrated by discussing a previously developed agent-based model, which explored inequalities in diet in the context of urban residential segregation.

  9. Brief introductory guide to agent-based modeling and an illustration from urban health research.

    Science.gov (United States)

    Auchincloss, Amy H; Garcia, Leandro Martin Totaro

    2015-11-01

    There is growing interest among urban health researchers in addressing complex problems using conceptual and computation models from the field of complex systems. Agent-based modeling (ABM) is one computational modeling tool that has received a lot of interest. However, many researchers remain unfamiliar with developing and carrying out an ABM, hindering the understanding and application of it. This paper first presents a brief introductory guide to carrying out a simple agent-based model. Then, the method is illustrated by discussing a previously developed agent-based model, which explored inequalities in diet in the context of urban residential segregation.

  10. RESPONSIVE URBAN MODELS BY PROCESSING SETS OF HETEROGENEOUS DATA

    Directory of Open Access Journals (Sweden)

    M. Calvano

    2018-05-01

    Full Text Available This paper presents some steps in experimentation aimed at describing urban spaces made following the series of earthquakes that affected a vast area of central Italy starting on 24 August 2016. More specifically, these spaces pertain to historical centres of limited size and case studies that can be called “problematic” (due to complex morphological and settlement conditions, because they are difficult to access, or because they have been affected by calamitous events, etc.. The main objectives were to verify the use of sets of heterogeneous data that are already largely available to define a workflow and develop procedures that would allow some of the steps to be automated as much as possible. The most general goal was to use the experimentation to define a methodology to approach the problem aimed at developing descriptive responsive models of the urban space, that is, morphological and computer-based models capable of being modified in relation to the constantly updated flow of input data.

  11. Supersampling and Network Reconstruction of Urban Mobility.

    Directory of Open Access Journals (Sweden)

    Oleguer Sagarra

    Full Text Available Understanding human mobility is of vital importance for urban planning, epidemiology, and many other fields that draw policies from the activities of humans in space. Despite the recent availability of large-scale data sets of GPS traces or mobile phone records capturing human mobility, typically only a subsample of the population of interest is represented, giving a possibly incomplete picture of the entire system under study. Methods to reliably extract mobility information from such reduced data and to assess their sampling biases are lacking. To that end, we analyzed a data set of millions of taxi movements in New York City. We first show that, once they are appropriately transformed, mobility patterns are highly stable over long time scales. Based on this observation, we develop a supersampling methodology to reliably extrapolate mobility records from a reduced sample based on an entropy maximization procedure, and we propose a number of network-based metrics to assess the accuracy of the predicted vehicle flows. Our approach provides a well founded way to exploit temporal patterns to save effort in recording mobility data, and opens the possibility to scale up data from limited records when information on the full system is required.

  12. Simple Urban Simulation Atop Complicated Models: Multi-Scale Equation-Free Computing of Sprawl Using Geographic Automata

    Directory of Open Access Journals (Sweden)

    Yu Zou

    2013-07-01

    Full Text Available Reconciling competing desires to build urban models that can be simple and complicated is something of a grand challenge for urban simulation. It also prompts difficulties in many urban policy situations, such as urban sprawl, where simple, actionable ideas may need to be considered in the context of the messily complex and complicated urban processes and phenomena that work within cities. In this paper, we present a novel architecture for achieving both simple and complicated realizations of urban sprawl in simulation. Fine-scale simulations of sprawl geography are run using geographic automata to represent the geographical drivers of sprawl in intricate detail and over fine resolutions of space and time. We use Equation-Free computing to deploy population as a coarse observable of sprawl, which can be leveraged to run automata-based models as short-burst experiments within a meta-simulation framework.

  13. Urban stormwater - greywater management system for sustainable urban water management at sub-watershed level

    Science.gov (United States)

    Singh Arora, Amarpreet

    2017-11-01

    Urban water management involves urban water supply (import, treatment and distribution of water), urban wastewater management (collection, treatment and disposal of urban sewage) and urban storm water management. Declining groundwater tables, polluted and declining sources of water, water scarcity in urban areas, unsatisfactory urban water supply and sanitation situation, pollution of receiving water bodies (including the ground water), and urban floods have become the concerns and issues of sustainable urban water management. This paper proposes a model for urban stormwater and sewage management which addresses these concerns and issues of sustainable urban water management. This model proposes segregation of the sewage into black water and greywater, and urban sub-watershed level stormwater-greywater management systems. During dry weather this system will be handling only the greywater and making the latter available as reclaimed water for reuse in place of the fresh water supply. During wet weather, the system will be taking care of (collection and treatment) both the storm water and the greywater, and the excess of the treated water will be disposed off through groundwater recharging. Application of this model in the Patiala city, Punjab, INDIA for selected urban sub-watersheds has been tried. Information and background data required for the conceptualization and design of the sub-watershed level urban stormwater-greywater management system was collected and the system has been designed for one of the sub-watersheds in the Patiala city. In this paper, the model for sustainable urban water management and the design of the Sub-watershed level Urban Stormwater-Greywater Management System are described.

  14. The demonstration test of urban EV rental system with 'Hypermini'

    Energy Technology Data Exchange (ETDEWEB)

    Teramoto, M.; Tohyama, E.; Kasai, J. [Nissan Motor Co. Ltd., Tochigi (Japan); Takayama, M. [Electric Technology for Automobile Traffic and Driving Association, Tokyo (Japan)

    2000-07-01

    The efforts taken by the Electric Technology for Automobile Traffic and Driving Association to address environmental pollution associated with traffic jams were discussed. An urban electric vehicle (EV) rent-a-car system has been proposed which combines the intelligent transportation system (ITS) and ultra small EVs as a fourth public traffic system after rail, bus and taxis. A demonstration test of this system began in October 1999 with the Suzuki Motor Corporation. A total of 30 small conversion EV and 20 ultra small EVs, called the 'Hypermini' were tested in the heavily populated Yokohama Minato Mirai 21 District (MM21). The impetus for the feasibility study was the lack of transportation from residential areas to stations and from stations to business areas. The objective was to provide a seamless traffic system for door-to-door service and to improve the use of vehicle parking spaces by an intelligent car sharing system. Another objective was to reduce the operating cost of company cars in urban areas. A comprehensive description of how the urban rent-a-car system works was included along with an overview of the system components and a description of vehicle stations. The solution to one-way-trips was solved by employing people to either drive or tow dropped-off vehicles to their original stations. So far, most users are satisfied with the service. Those with complaints, argued that the range was not sufficient. It was emphasized that in order for the system to be accepted nation wide, it is important to maintain low costs and high reliability in this demonstration stage.

  15. A technical review of urban land use - transportation models as tools for evaluating vehicle travel reduction strategies

    Energy Technology Data Exchange (ETDEWEB)

    Southworth, F.

    1995-07-01

    The continued growth of highway traffic in the United States has led to unwanted urban traffic congestion as well as to noticeable urban air quality problems. These problems include emissions covered by the 1990 Clean Air Act Amendments (CAAA) and 1991 Intermodal Surface Transportation Efficiency Act (ISTEA), as well as carbon dioxide and related {open_quotes}greenhouse gas{close_quotes} emissions. Urban travel also creates a major demand for imported oil. Therefore, for economic as well as environmental reasons, transportation planning agencies at both the state and metropolitan area level are focussing a good deal of attention on urban travel reduction policies. Much discussed policy instruments include those that encourage fewer trip starts, shorter trip distances, shifts to higher-occupancy vehicles or to nonvehicular modes, and shifts in the timing of trips from the more to the less congested periods of the day or week. Some analysts have concluded that in order to bring about sustainable reductions in urban traffic volumes, significant changes will be necessary in the way our households and businesses engage in daily travel. Such changes are likely to involve changes in the ways we organize and use traffic-generating and-attracting land within our urban areas. The purpose of this review is to evaluate the ability of current analytic methods and models to support both the evaluation and possibly the design of such vehicle travel reduction strategies, including those strategies involving the reorganization and use of urban land. The review is organized into three sections. Section 1 describes the nature of the problem we are trying to model, Section 2 reviews the state of the art in operational urban land use-transportation simulation models, and Section 3 provides a critical assessment of such models as useful urban transportation planning tools. A number of areas are identified where further model development or testing is required.

  16. The structure and dynamics of cities urban data analysis and theoretical modeling

    CERN Document Server

    Barthelemy, Marc

    2016-01-01

    With over half of the world's population now living in urban areas, the ability to model and understand the structure and dynamics of cities is becoming increasingly valuable. Combining new data with tools and concepts from statistical physics and urban economics, this book presents a modern and interdisciplinary perspective on cities and urban systems. Both empirical observations and theoretical approaches are critically reviewed, with particular emphasis placed on derivations of classical models and results, along with analysis of their limits and validity. Key aspects of cities are thoroughly analyzed, including mobility patterns, the impact of multimodality, the coupling between different transportation modes, the evolution of infrastructure networks, spatial and social organisation, and interactions between cities. Drawing upon knowledge and methods from areas of mathematics, physics, economics and geography, the resulting quantitative description of cities will be of interest to all those studying and r...

  17. Modelling heavy metals build-up on urban road surfaces for effective stormwater reuse strategy implementation

    International Nuclear Information System (INIS)

    Hong, Nian; Zhu, Panfeng; Liu, An

    2017-01-01

    Urban road stormwater is an alternative water resource to mitigate water shortage issues in the worldwide. Heavy metals deposited (build-up) on urban road surface can enter road stormwater runoff, undermining stormwater reuse safety. As heavy metal build-up loads perform high variabilities in terms of spatial distribution and is strongly influenced by surrounding land uses, it is essential to develop an approach to identify hot-spots where stormwater runoff could include high heavy metal concentrations and hence cannot be reused if it is not properly treated. This study developed a robust modelling approach to estimating heavy metal build-up loads on urban roads using land use fractions (representing percentages of land uses within a given area) by an artificial neural network (ANN) model technique. Based on the modelling results, a series of heavy metal load spatial distribution maps and a comprehensive ecological risk map were generated. These maps provided a visualization platform to identify priority areas where the stormwater can be safely reused. Additionally, these maps can be utilized as an urban land use planning tool in the context of effective stormwater reuse strategy implementation. - Highlights: • A model was developed to simulate heavy metal build-up loads on urban roads. • This model is based on artificial neural networks. • Land use fractions was used to model build-up loads on different particle sizes. • The maps of heavy metal spatial distribution and ecological risk were generated. • This model can be used for effective stormwater reuse strategy implementation. - Development of a robust modelling approach to mapping heavy metals build-up and their ecological risks for stormwater reuse safety.

  18. A partnership-based model for embedding employability in urban planning education

    Directory of Open Access Journals (Sweden)

    Neale Blair

    2016-01-01

    Full Text Available This paper proposes a partnership-based model for embedding employability in urban planning education. The model is based on the author’s experiences of implementing an international project which supported the development of employability skills in urban and regional planning education in Malawi. Since independence, urban planners have typically trained outside the country, attending university in the UK and other Commonwealth countries. More recently, the paradigm has shifted towards in-country education delivered by academic staff cognisant with the opportunities and challenges of development in Malawi. There remains, though, a gap between graduate knowledge of the subject and the skills necessary to pursue a professional career in the sector. Although there is no consensus yet on the meaning of employability in the literature, lessons from the project indicate that academic–public–private collaboration helps incorporate in curriculum skills that employers anticipate. Applicability of these principles is however context dependent, particularly in the emerging economy context where institutional capacity may be less developed compared to elsewhere.

  19. Overcoming the Subject-Object Dichotomy in Urban Modeling: Axial Maps as Geometric Representations of Affordances in the Built Environment

    Directory of Open Access Journals (Sweden)

    Lars Marcus

    2018-04-01

    Full Text Available The world is witnessing unprecedented urbanization, bringing extreme challenges to contemporary practices in urban planning and design. This calls for improved urban models that can generate new knowledge and enhance practical skill. Importantly, any urban model embodies a conception of the relation between humans and the physical environment. In urban modeling this is typically conceived of as a relation between human subjects and an environmental object, thereby reproducing a humans-environment dichotomy. Alternative modeling traditions, such as space syntax that originates in architecture rather than geography, have tried to overcome this dichotomy. Central in this effort is the development of new representations of urban space, such as in the case of space syntax, the axial map. This form of representation aims to integrate both human behavior and the physical environment into one and the same description. Interestingly, models based on these representations have proved to better capture pedestrian movement than regular models. Pedestrian movement, as well as other kinds of human flows in urban space, is essential for urban modeling, since increasingly flows of this kind are understood as the driver in urban processes. Critical for a full understanding of space syntax modeling is the ontology of its' representations, such as the axial map. Space syntax theory here often refers to James Gibson's “Theory of affordances,” where the concept of affordances, in a manner similar to axial maps, aims to bridge the subject-object dichotomy by neither constituting physical properties of the environment or human behavior, but rather what emerges in the meeting between the two. In extension of this, the axial map can be interpreted as a representation of how the physical form of the environment affords human accessibility and visibility in urban space. This paper presents a close examination of the form of representations developed in space syntax

  20. Event based uncertainty assessment in urban drainage modelling, applying the GLUE methodology

    DEFF Research Database (Denmark)

    Thorndahl, Søren; Beven, K.J.; Jensen, Jacob Birk

    2008-01-01

    of combined sewer overflow. The GLUE methodology is used to test different conceptual setups in order to determine if one model setup gives a better goodness of fit conditional on the observations than the other. Moreover, different methodological investigations of GLUE are conducted in order to test......In the present paper an uncertainty analysis on an application of the commercial urban drainage model MOUSE is conducted. Applying the Generalized Likelihood Uncertainty Estimation (GLUE) methodology the model is conditioned on observation time series from two flow gauges as well as the occurrence...... if the uncertainty analysis is unambiguous. It is shown that the GLUE methodology is very applicable in uncertainty analysis of this application of an urban drainage model, although it was shown to be quite difficult of get good fits of the whole time series....