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Sample records for advanced optimal traffic

  1. Principled negotiation and distributed optimization for advanced air traffic management

    Science.gov (United States)

    Wangermann, John Paul

    Today's aircraft/airspace system faces complex challenges. Congestion and delays are widespread as air traffic continues to grow. Airlines want to better optimize their operations, and general aviation wants easier access to the system. Additionally, the accident rate must decline just to keep the number of accidents each year constant. New technology provides an opportunity to rethink the air traffic management process. Faster computers, new sensors, and high-bandwidth communications can be used to create new operating models. The choice is no longer between "inflexible" strategic separation assurance and "flexible" tactical conflict resolution. With suitable operating procedures, it is possible to have strategic, four-dimensional separation assurance that is flexible and allows system users maximum freedom to optimize operations. This thesis describes an operating model based on principled negotiation between agents. Many multi-agent systems have agents that have different, competing interests but have a shared interest in coordinating their actions. Principled negotiation is a method of finding agreement between agents with different interests. By focusing on fundamental interests and searching for options for mutual gain, agents with different interests reach agreements that provide benefits for both sides. Using principled negotiation, distributed optimization by each agent can be coordinated leading to iterative optimization of the system. Principled negotiation is well-suited to aircraft/airspace systems. It allows aircraft and operators to propose changes to air traffic control. Air traffic managers check the proposal maintains required aircraft separation. If it does, the proposal is either accepted or passed to agents whose trajectories change as part of the proposal for approval. Aircraft and operators can use all the data at hand to develop proposals that optimize their operations, while traffic managers can focus on their primary duty of ensuring

  2. Optimizing Traffic Flow

    OpenAIRE

    Huberman, Bernardo A.; Helbing, Dirk

    1998-01-01

    We present an economics-based method for deciding the optimal rates at which vehicles are allowed to enter a highway. The method exploits the naturally occuring fluctuations of traffic flow and is flexible enough to adapt in real time to the transient flow characteristics of road traffic. Simulations based on realistic parameter values show that this strategy is feasible for naturally occuring traffic, and that even far from optimality, injection policies can improve traffic flow. Our results...

  3. An Advanced Fuzzy Logic Based Traffic Controller

    OpenAIRE

    Bilal Ahmed Khan; Nai Shyan Lai

    2014-01-01

    Traffic light plays an important role in the urban traffic management. Therefore, it is necessary to improve the traffic controller for effective traffic management and better traffic flow leading to greener environment. In this paper, an advanced and intelligent traffic light controller is proposed, utilising the fuzzy logic technology and image processing technique. A fuzzy logic control has been implemented to provide the attribute of intelligence to the system. For real-time image acquisi...

  4. Dividing the Traffic Matrix to Approach Optimal Traffic Engineering

    OpenAIRE

    Balon, Simon; Leduc, Guy

    2006-01-01

    In this paper we propose a new method to approach optimal Traffic Engineering routing. The method consists of dividing the traffic matrix into $N$ sub-matrices, called strata, and route each of these independently. We propose two different implementations of our method in routers. Our method can also be used to compute a very precise approximation of the optimal value of a given objective function for comparison to heuristic Traffic Engineering algorithms. For this application, our algorithm ...

  5. Traffic flow optimization on roundabouts

    OpenAIRE

    Delle Monache, Maria Laura; Obsu, Legesse Lemecha; Goatin, Paola; Kassa, Semu Mitiku

    2013-01-01

    The aim of this paper is to optimize the traffic flow on roundabouts using a macroscopic approach. The roundabout is modeled as a sequence of 2x2 junctions: with one mainline and secondary incoming and outgoing roads. We consider two cost functionals: the total travel time and the total waiting time, which give an estimate of the time spent by drivers on the network section. These cost functionals are minimized analytically for each junction with respect to the right of way parameter of the i...

  6. Fuzzy Multiobjective Traffic Light Signal Optimization

    OpenAIRE

    N. Shahsavari Pour; H. Asadi; M. Pour Kheradmand

    2013-01-01

    Traffic congestion is a major concern for many cities throughout the world. In a general traffic light controller, the traffic lights change at a constant cycle time. Hence it does not provide an optimal solution. Many traffic light controllers in current use are based on the “time-of-the-day” scheme, which use a limited number of predetermined traffic light patterns and implement these patterns depending upon the time of the day. These automated systems do not provide an optimal control for ...

  7. Green Wave Traffic Optimization - A Survey

    DEFF Research Database (Denmark)

    Warberg, Andreas; Larsen, Jesper; Jørgensen, Rene Munk

    important conflicts, which support the notion that traffic signal optimization is a multi-objective problem, and relates this to the most common measures of effectiveness. A distinction can be made between classical systems, which operate with a common cycle time, and the more flexible, phase......-based, approach, which is shown to be more suitable for adaptive traffic control. To support this claim three adaptive systems, which use alternatives to the classical optimization procedures, are described in detail....

  8. Traffic Flow Management and Optimization

    Science.gov (United States)

    Rios, Joseph Lucio

    2014-01-01

    This talk will present an overview of Traffic Flow Management (TFM) research at NASA Ames Research Center. Dr. Rios will focus on his work developing a large-scale, parallel approach to solving traffic flow management problems in the national airspace. In support of this talk, Dr. Rios will provide some background on operational aspects of TFM as well a discussion of some of the tools needed to perform such work including a high-fidelity airspace simulator. Current, on-going research related to TFM data services in the national airspace system and general aviation will also be presented.

  9. Advanced information feedback in intelligent traffic systems.

    Science.gov (United States)

    Wang, Wen-Xu; Wang, Bing-Hong; Zheng, Wen-Chen; Yin, Chuan-Yang; Zhou, Tao

    2005-12-01

    The optimal information feedback is very important to many socioeconomic systems like stock market and traffic systems aiming to make full use of resources. As to traffic flow, a reasonable real-time information feedback can improve the urban traffic condition by providing route guidance. In this paper, the influence of a feedback strategy named congestion coefficient feedback strategy is introduced, based on a two-route scenario in which dynamic information can be generated and displayed on the board to guide road users to make a choice. Simulation results adopting this optimal information feedback strategy have demonstrated high efficiency in controlling spatial distribution of traffic patterns compared with the other two information feedback strategies, i.e., travel time and mean velocity. PMID:16486093

  10. Optimization of Malicious Traffic in Optimal Source Based Filtering

    Directory of Open Access Journals (Sweden)

    P.MOHANRAJ

    2014-01-01

    Full Text Available Traffic and spam are the main problems in the data transmission through the network. Many traffic filtering systems have been proposed to find and filter the traffic over the network. The system Optimal Source Filtering (OSF has implemented a new and optimal filtering mechanism. The new mechanism named as DROP, which monitors and filters the spam and malicious traffic over a network effectively. Traffic filtering systems have been proposed to detect the spammer and malicious traffic, using the optimal rules and policies. Further these systems are highly ineffective when they encounter malicious traffic. The proposed system introduced OSF protocol, which helps to improve the efficiency of the firewall and filters based on the user rule. The proposed filtering scheme provides TFS false filtering when the flash crowd occurred. The protocol verifies users and firewall rules and policies with the data priority model, which makes the filtering process more robust and fastest manner. The Proposed spam detection project identifies and eliminates unwanted messages by monitoring outgoing messages. The spam detection is the main challenging task in the network. In the existing system spam detection has implemented after the data received. According to the user rule and request the current system identifies the spam and zombies by monitoring every outgoing message from the sender.

  11. CCN Traffic Optimization for IoT

    OpenAIRE

    Francois J; Cholez T.; Engel T.

    2013-01-01

    International audience Content-Centric Networking (CCN) recently received a lot of attention thanks to its elegant way to optimize content diffusion at the scale of Internet. However, communications occurring at the edge of Internet, in particular the Internet of Things (IoT), are also a vivid research topic. Even if CCN was not initially designed to optimize the specific traffic pattern of the IoT, it can be improved to better support these new applications. In this paper, we propose to o...

  12. Optimal traffic states in a cellular automaton for city traffic

    OpenAIRE

    Barlovic, Robert; Brockfeld, Elmar; Schreckenberg, Michael; Schadschneider, Andreas

    2003-01-01

    The impact of global traffic light control strategies for city networks is analyzed in a recently proposed cellular automaton model. The model combines basic ideas of the Biham-Middleton-Levine model for city traffic and the Nage-Schreckenberg model for highway traffic. The city network has a simple square lattice geometry. All streets and intersections are treated equally, i.e., there are no dominant streets.

  13. En-Route Vehicular Traffic Optimization

    Directory of Open Access Journals (Sweden)

    Saravanan M

    2015-02-01

    separately for each locality from the available data set. For efficient control in mobility of vehicles an advanced dynamic digital board is introduced, which displays the speed limit set by the central node time to time. The normalized speed could be used to estimate the effective time taken between destinations precisely. By comparing normalized speed with real time values anomalies in the locality like congestion and presence of uneven roads is predicted. Accident detection model is integrated with the central node which sends a message to dynamic board indicating location of the accident along with the time taken. It even improves traffic flow around the accident occurred location. Central node together with navigation tools could provide re-routed path to the drivers during congestion or accident.

  14. A Multiagent Simulation for Traffic Flow Management with Evolutionary Optimization

    OpenAIRE

    Filipiak, Patryk

    2011-01-01

    A traffic flow is one of the main transportation issues in nowadays industrialized agglomerations. Configuration of traffic lights is among the key aspects in traffic flow management. This paper proposes an evolutionary optimization tool that utilizes multiagent simulator in order to obtain accurate model. Even though more detailed studies are still necessary, a preliminary research gives an expectation for promising results.

  15. An Efficient PageRank Approach for Urban Traffic Optimization

    OpenAIRE

    Florin Pop; Ciprian Dobre

    2012-01-01

    The cities are not static environments. They change constantly. When we talk about traffic in the city, the evolution of traffic lights is a journey from mindless automation to increasingly intelligent, fluid traffic management. In our approach, presented in this paper, reinforcement-learning mechanism based on cost function is introduced to determine optimal decisions for each traffic light, based on the solution given by Larry Page for page ranking in Web environment (Page et al. (1999)). O...

  16. Research advances of traffic medicine in China

    Institute of Scientific and Technical Information of China (English)

    王正国; 蒋建新

    1999-01-01

    Objective:To briefly introduce the increase in the number of motor vehicles in our country and main research advances of traffic medicine.Methods:To collect the relative data issued by government and the papers pulished in the newspapers or medical journals,and analyze them with combination of our own research work. Results:1.The number of motor vehicles in our country in 1997 was 680.02 times more than that in 1951,and increases t 42.0932 million from 1.5887 million over the past two decades(1978-1997)since the reform and opening,with net increase of 40.5045 million,increasing about 25 times.During the same period,the number of motorcycles increased to 20.2221 million from 104.3 thousand,increasing about 193 times.There were 4.4 hundred million bicycles,accounting for one third or the total world wide,Over 30% to 50% of eople in cities used bicycles as their transport tool when they go out.2.In the 1990's (9190 to 1997),the number of motor vehicles increased 1.85 times,while road traffic accidents(RATs) only increased 0.22 times,the deaths and the injuries 0.5 and 0.23 times only,respectively,indicating that the increasing tendency of RTAs and casualties was controlled to some extent.3.The prople of 21 to 45 years old were dominant among all casualties.The sequence of deaths in order was pedestrians(26.5%),vehicle drivers(24.8%),passengers(24.3%),bicyclists(18.4%)and others (6.1%).4.Concerning the accident causes,human faults accounted for 92.9%,83.6% of RTAs wre due to the faults of motor vehicle drivers,and 1.5% of RTAs were due to driving after drinking with deaths occupying 2.9% of the total.5.Proneness to RTSs:6%-8% of motor vehical drivers had proneness to RTA,causing 35%-40% fo the totoal RTAs.6.Various bio-impact machines were developed.The maximum impact velocity could reach 324 km/h.They can be used to induce impact injuries on different animals,at different patterns and even on different regions of body.7.The inflicting mechanisms for cranioserebral and

  17. System optimal traffic assignment with departure time choice

    OpenAIRE

    Chow, A. H. F.

    2007-01-01

    This thesis investigates analytical dynamic system optimal assignment with departure time choice in a rigorous and original way. Dynamic system optimal assignment is formulated here as a state-dependent optimal control problem. A fixed volume of traffic is assigned to departure times and routes such that the total system travel cost is minimized. Although the system optimal assignment is not a realistic representation of traffic, it provides a bound on performance and shows how...

  18. Particle Swarm Optimization of Speed in Unplanned Lane Traffic

    Directory of Open Access Journals (Sweden)

    Prasun Ghosal

    2012-08-01

    Full Text Available Analysis of Speed Optimization Technique in Traffic is a very promising research problem. Searching foran efficient optimization method to increase the degree of speed optimization and thereby increasing thetraffic flow in a lane is a widely concerning issue. However, there has been a limited research effort on theoptimization of the lane usage with speed optimization. This paper presents a novel technique to solve theproblem optimally using the knowledge base analysis of speeds of vehicles, population of lanes , usingpartial modification of Swarm Intelligence which, in turn will act as a guide for design of lanes optimally toprovide better optimized traffic with less number of transitions of vehicles between lanes..

  19. Particle Swarm Optimization of Speed in Unplanned Lane Traffic

    Directory of Open Access Journals (Sweden)

    Prasun Ghosal

    2012-07-01

    Full Text Available Analysis of Speed Optimization Technique in Traffic is a very promising research problem. Searching for an efficient optimization method to increase the degree of speed optimization and thereby increasing the traffic flow in a lane is a widely concerning issue. However, there has been a limited research effort on the optimization of the lane usage with speed optimization. This paper presents a novel technique to solve the problem optimally using the knowledge base analysis of speeds of vehicles, population of lanes , using partial modification of Swarm Intelligence which, in turn will act as a guide for design of lanes optimally to provide better optimized traffic with less number of transitions of vehicles between lanes..

  20. Optimizing Traffic Operation in Designing Specific Upgrades

    Directory of Open Access Journals (Sweden)

    Ebrahim Sangsefidi

    2015-01-01

    Full Text Available Transport forms one of the primary needs in all categories of the population in modern society; it is of paramount concern for traffic engineers, transport planners, and policy makers to understand and evaluate the quality of service being provided by the transport facilities designed by them. This paper presents an investigation in profile geometric design and traffic flow operation on two-lane two-way highways and provides analyses that will help in a better understanding of traffic operation on these facilities to select the optimum profile configuration. The effects of influencing parameters consisting of grade, length of grade, traffic composition, and traffic volume are evaluated and finally a systematic procedure to evaluate flow rate under the base condition is presented. Finally, based on these achievements an algorithm is introduced to select optimum Finished Ground of profile view. Results show that the percentage of heavy vehicles has a contributing effect on traffic operation so that the optimum profile configuration is incredibly affected by this factor. Source data have been obtained from Highway Capacity Manual (HCM as a pioneer document in respect of quantifying the concept of capacity for a transport facility.

  1. Advanced backend optimization

    CERN Document Server

    Touati, Sid

    2014-01-01

    This book is a summary of more than a decade of research in the area of backend optimization. It contains the latest fundamental research results in this field. While existing books are often more oriented toward Masters students, this book is aimed more towards professors and researchers as it contains more advanced subjects.It is unique in the sense that it contains information that has not previously been covered by other books in the field, with chapters on phase ordering in optimizing compilation; register saturation in instruction level parallelism; code size reduction for software pipe

  2. Optimization of TTEthernet Networks to Support Best-Effort Traffic

    DEFF Research Database (Denmark)

    Tamas-Selicean, Domitian; Pop, Paul

    2014-01-01

    This paper focuses on the optimization of the TTEthernet communication protocol, which offers three traffic classes: time-triggered (TT), sent according to static schedules, rate-constrained (RC) that has bounded end-to-end latency, and best-effort (BE), the classic Ethernet traffic, with no timing...... guarantees. In our earlier work we have proposed an optimization approach named DOTTS that performs the routing, scheduling and packing / fragmenting of TT and RC messages, such that the TT and RC traffic is schedulable. Although backwards compatibility with classic Ethernet networks is one of TTEthernet......’s strong points, there is little research on this topic. However, in this paper, we extend our DOTTS optimization approach to optimize TTEthernet networks, such that not only the TT and RC messages are schedulable, but we also maximize the available bandwidth for BE messages. The proposed optimization has...

  3. A Survey of Network Optimization Techniques for Traffic Engineering

    OpenAIRE

    Fedrigo, Enrico; Granelli, Fabrizio

    2008-01-01

    TCP/IP represents the reference standard for the implementation of interoperable communication networks. Nevertheless, the layering principle at the basis of interoperability severely limits the performance of data communication networks, thus requiring proper configuration and management in order to provide effective management of traffic flows. This paper presents a brief survey related to network optimization using Traffic Engineering algorithms, aiming at providing additional insight to t...

  4. Optimal Control of Hybrid Systems in Air Traffic Applications

    Science.gov (United States)

    Kamgarpour, Maryam

    Growing concerns over the scalability of air traffic operations, air transportation fuel emissions and prices, as well as the advent of communication and sensing technologies motivate improvements to the air traffic management system. To address such improvements, in this thesis a hybrid dynamical model as an abstraction of the air traffic system is considered. Wind and hazardous weather impacts are included using a stochastic model. This thesis focuses on the design of algorithms for verification and control of hybrid and stochastic dynamical systems and the application of these algorithms to air traffic management problems. In the deterministic setting, a numerically efficient algorithm for optimal control of hybrid systems is proposed based on extensions of classical optimal control techniques. This algorithm is applied to optimize the trajectory of an Airbus 320 aircraft in the presence of wind and storms. In the stochastic setting, the verification problem of reaching a target set while avoiding obstacles (reach-avoid) is formulated as a two-player game to account for external agents' influence on system dynamics. The solution approach is applied to air traffic conflict prediction in the presence of stochastic wind. Due to the uncertainty in forecasts of the hazardous weather, and hence the unsafe regions of airspace for aircraft flight, the reach-avoid framework is extended to account for stochastic target and safe sets. This methodology is used to maximize the probability of the safety of aircraft paths through hazardous weather. Finally, the problem of modeling and optimization of arrival air traffic and runway configuration in dense airspace subject to stochastic weather data is addressed. This problem is formulated as a hybrid optimal control problem and is solved with a hierarchical approach that decouples safety and performance. As illustrated with this problem, the large scale of air traffic operations motivates future work on the efficient

  5. Traffic Based Optimization of Spectrum Sensing in Cognitive Radio Networks

    Directory of Open Access Journals (Sweden)

    Changhua Yao

    2014-01-01

    Full Text Available We propose a more practical spectrum sensing optimization problem in cognitive radio networks (CRN, by considering the data traffic of second user (SU. Compared with most existing work, we do not assume that SU always has packets to transmit; instead, we use the actual data transmitted per second rather than the channel capacity as the achievable throughput, to reformulate the Sensing-Throughput Tradeoff problem. We mathematically analyze the problem of optimal sensing time to maximize the achievable throughput, based on the data traffic of SU. Our model is more general because the traditional Sensing-Throughput Tradeoff model can be seen as a special case of our model. We also prove that the throughput is a concave function of sensing time and there is only one optimal sensing time value which is determined by the data traffic. Simulation results show that the proposed approach outperforms existing methods.

  6. Traffic Flow Control - Optimization on Horizon

    Czech Academy of Sciences Publication Activity Database

    Homolová, Jitka

    Praha: ÚTIA AV ČR, 2006 - (Přikryl, J.; Šmídl, V.). s. 43-44 [International PhD Workshop on Interplay of Societal and Technical Decision - Making , Young Generation Viewpoint /7./. 25.09.2006-30.09.2006, Hrubá Skála] Grant ostatní: MD ČR(CZ) 1F43A/003/120 Institutional research plan: CEZ:AV0Z10750506 Keywords : linear programming * traffic flow control * control on horizon Subject RIV: BC - Control Systems Theory

  7. Optimizing urban traffic control using a rational agent

    Institute of Scientific and Technical Information of China (English)

    Salvador IBARRA-MARTÍNEZ; José A. CASTÁN-ROCHA; Julio LARIA-MENCHACA

    2014-01-01

    This paper is devoted to developing and evaluating a set of technologies with the objective of designing a method-ology for the implementation of sophisticated traffic lights by means of rational agents. These devices would be capable of op-timizing the behavior of a junction with multiple traffic signals, reaching a higher level of autonomy without losing reliability, accuracy, or efficiency in the offered services. In particular, each rational agent in a traffic signal will be able to analyze the requirements and constraints of the road, in order to know its level of demand. With such information, the rational agent will adapt its light cycles with the view of accomplishing more fluid traffic patterns and minimizing the pollutant environmental emissions produced by vehicles while they are stopped at a red light, through using a case-based reasoning (CBR) adaptation. This paper also integrates a microscopic simulator developed to run a set of tests in order to compare the presented methodology with traditional traffic control methods. Two study cases are shown to demonstrate the efficiency of the introduced approach, increasing vehicular mobility and reducing harmful activity for the environment. For instance, in the first scenario, taking into account the studied traffic volumes, our approach increases mobility by 23%and reduces emissions by 35%. When the roads are managed by sophisticated traffic lights, a better level of service and considerable environmental benefits are achieved, demon-strating the utility of the presented approach.

  8. One More Weight is Enough: Toward the Optimal Traffic Engineering with OSPF

    CERN Document Server

    Xu, Ke; Liu, Jiangchuan; Shen, Meng

    2010-01-01

    Traffic Engineering (TE) leverages information of network traffic to generate a routing scheme optimizing the traffic distribution so as to advance network performance. However, optimize the link weights for OSPF to the offered traffic is an known NP-hard problem. In this paper, motivated by the fairness concept of congestion control, we firstly propose a new generic objective function, where various interests of providers can be extracted with different parameter settings. And then, we model the optimal TE as the utility maximization of multi-commodity flows with the generic objective function and theoretically show that any given set of optimal routes corresponding to a particular objective function can be converted to shortest paths with respect to a set of positive link weights. This can be directly configured on OSPF-based protocols. On these bases, we employ the Network Entropy Maximization(NEM) framework and develop a new OSPF-based routing protocol, SPEF, to realize a flexible way to split traffic ove...

  9. Constrained optimal steady-state control for isolated traffic intersections

    Institute of Scientific and Technical Information of China (English)

    Jack HADDAD; David MAHALEL; Ilya IOSLOVICH; Per-Olof GUTMAN

    2014-01-01

    The steady-state or cyclic control problem for a simplified isolated traffic intersection is considered. The optimization problem for the green-red switching sequence is formulated with the help of a discrete-event max-plus model. Two steady-state control problems are formulated: optimal steady-state with green duration constraints, and optimal steady-state control with lost time. In the case when the criterion is a strictly increasing, linear function of the queue lengths, the steady-state control problems can be solved analytically. The structure of constrained optimal steady-state traffic control is revealed, and the effect of the lost time on the optimal solution is illustrated.

  10. Advanced Interactive Display Formats for Terminal Area Traffic Control

    Science.gov (United States)

    Grunwald, Arthur J.; Shaviv, G. E.

    1999-01-01

    This research project deals with an on-line dynamic method for automated viewing parameter management in perspective displays. Perspective images are optimized such that a human observer will perceive relevant spatial geometrical features with minimal errors. In order to compute the errors at which observers reconstruct spatial features from perspective images, a visual spatial-perception model was formulated. The model was employed as the basis of an optimization scheme aimed at seeking the optimal projection parameter setting. These ideas are implemented in the context of an air traffic control (ATC) application. A concept, referred to as an active display system, was developed. This system uses heuristic rules to identify relevant geometrical features of the three-dimensional air traffic situation. Agile, on-line optimization was achieved by a specially developed and custom-tailored genetic algorithm (GA), which was to deal with the multi-modal characteristics of the objective function and exploit its time-evolving nature.

  11. Traffic Based Optimization of Spectrum Sensing in Cognitive Radio Networks

    OpenAIRE

    Changhua Yao; Qihui Wu; Linfang Zhou

    2014-01-01

    We propose a more practical spectrum sensing optimization problem in cognitive radio networks (CRN), by considering the data traffic of second user (SU). Compared with most existing work, we do not assume that SU always has packets to transmit; instead, we use the actual data transmitted per second rather than the channel capacity as the achievable throughput, to reformulate the Sensing-Throughput Tradeoff problem. We mathematically analyze the problem of optimal sensing time to maximize the ...

  12. Cloud-based large-scale air traffic flow optimization

    Science.gov (United States)

    Cao, Yi

    The ever-increasing traffic demand makes the efficient use of airspace an imperative mission, and this paper presents an effort in response to this call. Firstly, a new aggregate model, called Link Transmission Model (LTM), is proposed, which models the nationwide traffic as a network of flight routes identified by origin-destination pairs. The traversal time of a flight route is assumed to be the mode of distribution of historical flight records, and the mode is estimated by using Kernel Density Estimation. As this simplification abstracts away physical trajectory details, the complexity of modeling is drastically decreased, resulting in efficient traffic forecasting. The predicative capability of LTM is validated against recorded traffic data. Secondly, a nationwide traffic flow optimization problem with airport and en route capacity constraints is formulated based on LTM. The optimization problem aims at alleviating traffic congestions with minimal global delays. This problem is intractable due to millions of variables. A dual decomposition method is applied to decompose the large-scale problem such that the subproblems are solvable. However, the whole problem is still computational expensive to solve since each subproblem is an smaller integer programming problem that pursues integer solutions. Solving an integer programing problem is known to be far more time-consuming than solving its linear relaxation. In addition, sequential execution on a standalone computer leads to linear runtime increase when the problem size increases. To address the computational efficiency problem, a parallel computing framework is designed which accommodates concurrent executions via multithreading programming. The multithreaded version is compared with its monolithic version to show decreased runtime. Finally, an open-source cloud computing framework, Hadoop MapReduce, is employed for better scalability and reliability. This framework is an "off-the-shelf" parallel computing model

  13. Traffic optimization in transport networks based on local routing

    Science.gov (United States)

    Scellato, S.; Fortuna, L.; Frasca, M.; Gómez-Gardeñes, J.; Latora, V.

    2010-01-01

    Congestion in transport networks is a topic of theoretical interest and practical importance. In this paper we study the flow of vehicles in urban street networks. In particular, we use a cellular automata model on a complex network to simulate the motion of vehicles along streets, coupled with a congestion-aware routing at street crossings. Such routing makes use of the knowledge of agents about traffic in nearby roads and allows the vehicles to dynamically update the routes towards their destinations. By implementing the model in real urban street patterns of various cities, we show that it is possible to achieve a global traffic optimization based on local agent decisions.

  14. Road Traffic System: Optimization Using Ant Systems

    OpenAIRE

    Yeong, Kim Ming

    2003-01-01

    Let us look at these social insects, which are relatively simple however, they can perform effective strategy following the simple, adaptive to local rules, which allows them to change according to the environment for survival. This uniqueness of the insect world helps us to understand that complex situation does have solution. The study of ant colonies behavior is an interesting issue that provides good modeling solution for difficult optimization and distributed control problems. Transporta...

  15. Traffic Congestion Evaluation and Signal Control Optimization Based on Wireless Sensor Networks: Model and Algorithms

    OpenAIRE

    Wei Zhang; Guozhen Tan; Nan Ding; Guangyuan Wang

    2012-01-01

    This paper presents the model and algorithms for traffic flow data monitoring and optimal traffic light control based on wireless sensor networks. Given the scenario that sensor nodes are sparsely deployed along the segments between signalized intersections, an analytical model is built using continuum traffic equation and develops the method to estimate traffic parameter with the scattered sensor data. Based on the traffic data and principle of traffic congestion formation, we introduce the ...

  16. Optimization of congested traffic flow in systems with a localized periodic inhomogeneity

    OpenAIRE

    Tomer, Elad; Safonov, Leonid; Madar, Nilly; Havlin, Shlomo

    2001-01-01

    We study traffic flow on roads with a localized periodic inhomogeneity such as traffic signals, using a stochastic car-following model. We find that in cases of congestion, traffic flow can be optimized by controlling the inhomogeneity's frequency. By studying the wavelength dependence of the flux in stop-and-go traffic states, and exploring their stability, we are able to explain the optimization process. A general conclusion drawn from this study is, that the fundamental diagram of traffic ...

  17. Optimal Source-Based Filtering of Malicious Traffic

    CERN Document Server

    Soldo, Fabio; Markopoulou, Athina

    2010-01-01

    In this paper, we consider the problem of blocking malicious traffic on the Internet, via source-based filtering. In particular, we consider filtering via access control lists (ACLs): these are already available at the routers today but are a scarce resource because they are stored in the expensive ternary content addressable memory (TCAM). Aggregation (by filtering source prefixes instead of individual IP addresses) helps reduce the number of filters, but comes also at the cost of blocking legitimate traffic originating from the filtered prefixes. We show how to optimally choose which source prefixes to filter, for a variety of realistic attack scenarios and operators' policies. In each scenario, we design optimal, yet computationally efficient, algorithms. Using logs from Dshield.org, we evaluate the algorithms and demonstrate that they bring significant benefit in practice.

  18. Traffic

    International Nuclear Information System (INIS)

    This chapter deals with passenger and freight traffic, public and private transportation, traffic related environmental impacts, future developments, traffic indicators, regional traffic planning, health costs due to road traffic related air pollution, noise pollution, measures and regulations for traffic control and fuels for traffic. In particular energy consumption, energy efficiency, pollutant emissions ( CO2, SO2, NOx, HC, CO, N2O, NH3 and particulates) and environmental effects of the different types of traffic and different types of fuels are compared and studied. Legal regulations and measures for an effective traffic control are discussed. (a.n.)

  19. OPTIMIZATION OF URBAN MULTI-INTERSECTION TRAFFIC FLOW VIA Q-LEARNING

    Directory of Open Access Journals (Sweden)

    Yit Kwong Chin

    2013-01-01

    Full Text Available Congestions of the traffic flow within the urban traffic network have been a challenging task for all the urban developers. Many approaches have been introduced into the current system to solve the traffic congestion problems. Reconfiguration of the traffic signal timing plan has been carried out through implementation of different techniques. However, dynamic characteristics of the traffic flow increase the difficulties towards the ultimate solutions. Thus, traffic congestions still remain as unsolvable problems to the current traffic control system. In this study, artificial intelligence method has been introduced in the traffic light system to alter the traffic signal timing plan to optimize the traffic flows. Q-learning algorithm in this study has enhanced the traffic light system with learning ability. The learning mechanism of Q-learning enables traffic light intersections to release itself from traffic congestions situation. Adjacent traffic light intersections will work independently and yet cooperate with each others to a common goal of ensuring the fluency of the traffic flows within the traffic network. The simulated results show that the Q-Learning algorithm is able to learn from the dynamic traffic flow and optimize the traffic flow accordingly.

  20. Trafficability Analysis at Traffic Crossing and Parameters Optimization Based on Particle Swarm Optimization Method

    OpenAIRE

    Bin He; Qiang Lu

    2014-01-01

    In city traffic, it is important to improve transportation efficiency and the spacing of platoon should be shortened when crossing the street. The best method to deal with this problem is automatic control of vehicles. In this paper, a mathematical model is established for the platoon’s longitudinal movement. A systematic analysis of longitudinal control law is presented for the platoon of vehicles. However, the parameter calibration for the platoon model is relatively difficult because the p...

  1. Traffic Congestion Evaluation and Signal Control Optimization Based on Wireless Sensor Networks: Model and Algorithms

    Directory of Open Access Journals (Sweden)

    Wei Zhang

    2012-01-01

    Full Text Available This paper presents the model and algorithms for traffic flow data monitoring and optimal traffic light control based on wireless sensor networks. Given the scenario that sensor nodes are sparsely deployed along the segments between signalized intersections, an analytical model is built using continuum traffic equation and develops the method to estimate traffic parameter with the scattered sensor data. Based on the traffic data and principle of traffic congestion formation, we introduce the congestion factor which can be used to evaluate the real-time traffic congestion status along the segment and to predict the subcritical state of traffic jams. The result is expected to support the timing phase optimization of traffic light control for the purpose of avoiding traffic congestion before its formation. We simulate the traffic monitoring based on the Mobile Century dataset and analyze the performance of traffic light control on VISSIM platform when congestion factor is introduced into the signal timing optimization model. The simulation result shows that this method can improve the spatial-temporal resolution of traffic data monitoring and evaluate traffic congestion status with high precision. It is helpful to remarkably alleviate urban traffic congestion and decrease the average traffic delays and maximum queue length.

  2. Mechanical Design Optimization Using Advanced Optimization Techniques

    CERN Document Server

    Rao, R Venkata

    2012-01-01

    Mechanical design includes an optimization process in which designers always consider objectives such as strength, deflection, weight, wear, corrosion, etc. depending on the requirements. However, design optimization for a complete mechanical assembly leads to a complicated objective function with a large number of design variables. It is a good practice to apply optimization techniques for individual components or intermediate assemblies than a complete assembly. Analytical or numerical methods for calculating the extreme values of a function may perform well in many practical cases, but may fail in more complex design situations. In real design problems, the number of design parameters can be very large and their influence on the value to be optimized (the goal function) can be very complicated, having nonlinear character. In these complex cases, advanced optimization algorithms offer solutions to the problems, because they find a solution near to the global optimum within reasonable time and computational ...

  3. Traveling waves in an optimal velocity model of freeway traffic

    Science.gov (United States)

    Berg, Peter; Woods, Andrew

    2001-03-01

    Car-following models provide both a tool to describe traffic flow and algorithms for autonomous cruise control systems. Recently developed optimal velocity models contain a relaxation term that assigns a desirable speed to each headway and a response time over which drivers adjust to optimal velocity conditions. These models predict traffic breakdown phenomena analogous to real traffic instabilities. In order to deepen our understanding of these models, in this paper, we examine the transition from a linear stable stream of cars of one headway into a linear stable stream of a second headway. Numerical results of the governing equations identify a range of transition phenomena, including monotonic and oscillating travelling waves and a time- dependent dispersive adjustment wave. However, for certain conditions, we find that the adjustment takes the form of a nonlinear traveling wave from the upstream headway to a third, intermediate headway, followed by either another traveling wave or a dispersive wave further downstream matching the downstream headway. This intermediate value of the headway is selected such that the nonlinear traveling wave is the fastest stable traveling wave which is observed to develop in the numerical calculations. The development of these nonlinear waves, connecting linear stable flows of two different headways, is somewhat reminiscent of stop-start waves in congested flow on freeways. The different types of adjustments are classified in a phase diagram depending on the upstream and downstream headway and the response time of the model. The results have profound consequences for autonomous cruise control systems. For an autocade of both identical and different vehicles, the control system itself may trigger formations of nonlinear, steep wave transitions. Further information is available [Y. Sugiyama, Traffic and Granular Flow (World Scientific, Singapore, 1995), p. 137].

  4. High-Speed Network Traffic Management Analysis and Optimization: Models and Methods

    OpenAIRE

    Zaborovski, V.; Yegorov, S.; Podgurski, Y.; Shemanin, Y.

    1997-01-01

    The main steps of automatic control methodology include the hierarchical representation of management system and the formal definitions of input variables, object and goal of control of each management level. A Petri net model of individual traffic source is presented. It is noted that the current set of traffic parameters recommended by ATM-forum is not enough to synthesize optimal traffic control system. The feature of traffic self-similarity can be used to effectively solve optimal control...

  5. Search Engine Optimization: What Drives Organic Traffic to Retail Sites?

    OpenAIRE

    Baye, Michael R.; Babur De los Santos; Matthijs R. Wildenbeest

    2013-01-01

    The lion’s share of retail traffic through search engines originates from organic (natural) rather than sponsored (paid) links. We use a dataset constructed from over 12,000 search terms and 2 million users to identify drivers of the organic clicks that the top 759 retailers received from search engines in August 2012. Our results are potentially important for search engine optimization (SEO). We find that a retailer’s investments in factors such as the quality and brand awareness of its site...

  6. Recent advances in computational optimization

    CERN Document Server

    2013-01-01

    Optimization is part of our everyday life. We try to organize our work in a better way and optimization occurs in minimizing time and cost or the maximization of the profit, quality and efficiency. Also many real world problems arising in engineering, economics, medicine and other domains can be formulated as optimization tasks. This volume is a comprehensive collection of extended contributions from the Workshop on Computational Optimization. This book presents recent advances in computational optimization. The volume includes important real world problems like parameter settings for con- trolling processes in bioreactor, robot skin wiring, strip packing, project scheduling, tuning of PID controller and so on. Some of them can be solved by applying traditional numerical methods, but others need a huge amount of computational resources. For them it is shown that is appropriate to develop algorithms based on metaheuristic methods like evolutionary computation, ant colony optimization, constrain programming etc...

  7. Incorporating User Preferences Within an Optimal Traffic Flow Management Framework

    Science.gov (United States)

    Rios, Joseph Lucio; Sheth, Kapil S.; Guiterrez-Nolasco, Sebastian Armardo

    2010-01-01

    The effectiveness of future decision support tools for Traffic Flow Management in the National Airspace System will depend on two major factors: computational burden and collaboration. Previous research has focused separately on these two aspects without consideration of their interaction. In this paper, their explicit combination is examined. It is shown that when user preferences are incorporated with an optimal approach to scheduling, runtime is not adversely affected. A benefit-cost ratio is used to measure the influence of user preferences on an optimal solution. This metric shows user preferences can be accommodated without inordinately, negatively affecting the overall system delay. Specifically, incorporating user preferences will increase delays proportionally to increased user satisfaction.

  8. TO THE QUESTION OF SOLVING OF THE PROBLEM OF OPTIMIZING PARAMETERS OF TRAFFIC FLOW COORDINATED CONTROL

    OpenAIRE

    L. Abramova; Chernobaev, N.

    2007-01-01

    A short review of main methods of traffic flow control is represented, great attention is paid to methods of coordinated control and quality characteristics of traffic control. The problem of parameter optimization of traffic coordinated control on the basis of vehicle delay minimizing at highway intersections has been defined.

  9. Stabilization of traffic flow in optimal velocity model via delayed-feedback control

    Science.gov (United States)

    Jin, Yanfei; Hu, Haiyan

    2013-04-01

    Traffic jams may occur due to various reasons, such as traffic accidents, lane reductions and on-ramps. In order to suppress the traffic congestion in an optimal velocity traffic model without any driver's delay taken into account, a delayed-feedback control of both displacement and velocity differences is proposed in this study. By using the delay-independent stability criteria and the H∞-norm, the delayed-feedback control can be determined to stabilize the unstable traffic flow and suppress the traffic jam. The numerical case studies are given to demonstrate and verify the new control method. Furthermore, a comparison is made between the new control method and the method proposed by Konishi et al. [K. Konishi, M. Hirai, H. Kokame, Decentralized delayed-feedback control of an optimal velocity traffic model, Eur. Phys. J. B 15 (2000) 715-722]. The results show that the new control method makes the traffic flow more stable and improves the control performance.

  10. Perturbation analysis and sample-path optimization: stochastic flow models of urban traffic networks case

    OpenAIRE

    Sutarto, Herman; Boel, René

    2009-01-01

    Coordination of traffic streams in an urban network, controllable by switching traffic lights, requires a global macroscopic model of the evolution of the flows of vehicle. We propose the use fluid petri nets as modeling tools. For the design of on-line controllers for traffic lights we study the network-wide effects of different local perturbations of the traffic light switching times via fast simulation. The infinitesimal perturbation analysis can under certain conditions lead to optimal cl...

  11. Dynamic stochastic optimization models for air traffic flow management

    Science.gov (United States)

    Mukherjee, Avijit

    This dissertation presents dynamic stochastic optimization models for Air Traffic Flow Management (ATFM) that enables decisions to adapt to new information on evolving capacities of National Airspace System (NAS) resources. Uncertainty is represented by a set of capacity scenarios, each depicting a particular time-varying capacity profile of NAS resources. We use the concept of a scenario tree in which multiple scenarios are possible initially. Scenarios are eliminated as possibilities in a succession of branching points, until the specific scenario that will be realized on a particular day is known. Thus the scenario tree branching provides updated information on evolving scenarios, and allows ATFM decisions to be re-addressed and revised. First, we propose a dynamic stochastic model for a single airport ground holding problem (SAGHP) that can be used for planning Ground Delay Programs (GDPs) when there is uncertainty about future airport arrival capacities. Ground delays of non-departed flights can be revised based on updated information from scenario tree branching. The problem is formulated so that a wide range of objective functions, including non-linear delay cost functions and functions that reflect equity concerns can be optimized. Furthermore, the model improves on existing practice by ensuring efficient use of available capacity without necessarily exempting long-haul flights. Following this, we present a methodology and optimization models that can be used for decentralized decision making by individual airlines in the GDP planning process, using the solutions from the stochastic dynamic SAGHP. Airlines are allowed to perform cancellations, and re-allocate slots to remaining flights by substitutions. We also present an optimization model that can be used by the FAA, after the airlines perform cancellation and substitutions, to re-utilize vacant arrival slots that are created due to cancellations. Finally, we present three stochastic integer programming

  12. High-Speed Network Traffic Management Analysis and Optimization Models and Methods

    CERN Document Server

    Zaborovski, V; Podgurski, Y; Shemanin, Y

    1997-01-01

    The main steps of automatic control methodology include the hierarchical representation of management system and the formal definitions of input variables, object and goal of control of each management level. A Petri net model of individual traffic source is presented. It is noted that the current set of traffic parameters recommended by ATM-forum is not enough to synthesize optimal traffic control system. The feature of traffic self-similarity can be used to effectively solve optimal control task. An example of an optimal control scheme for cell discarding algorithm is presented.

  13. A simulation optimization-based decision support tool for mitigating traffic congestion

    OpenAIRE

    S H Melouk; B B Keskin; C Armbrester; M. Anderson

    2011-01-01

    Traffic congestion has grown considerably in the United States over the past 20 years. In this paper, we develop a robust decision support tool based on simulation optimization to evaluate and recommend congestion mitigation strategies to transportation system decision-makers. A tabu search-based optimizer determines different network design strategies on the road network while a traffic simulator evaluates the goodness of fit. The tool is tested with real-world traffic data.

  14. Identification and optimization of traffic bottleneck with signal timing

    OpenAIRE

    Shaoxin Yuan; Xiangmo Zhao; Yisheng An

    2014-01-01

    In urban transportation network, traffic congestion is likely to occur at traffic bottlenecks. The signal timing at intersections together with static properties of left-turn and straight-through lanes of roads are two significant factors causing traffic bottlenecks. A discrete-time model of traffic bottleneck is hence developed to analyze these two factors, and a bottleneck indicator is introduced to estimate the comprehensive bottleneck degree of individual road in regional transportation n...

  15. Optimal traffic light control method for a single intersection based on hybrid systems

    Institute of Scientific and Technical Information of China (English)

    赵晓华; 陈阳舟; 崔平远

    2003-01-01

    A single intersection of two phases is selected as a model to put forward a new optimal time-planning scheme for traffic light based on the model of hybrid automata for single intersection. A method of optimization is proposed for hybrid systems, and the average queue length over all queues is used as an objective function to find an optimal switching scheme for traffic light. It is illustrated that traffic light control for single intersection is a typical hybrid system, and the optimal planning-time scheme can be obtained using the optimal hybrid systems control based on the two stages method.

  16. Optimized Energy Management for Mixed Uplink Traffic in LTE UE

    Directory of Open Access Journals (Sweden)

    Vinod Mirchandani

    2013-03-01

    Full Text Available Battery life is a major issue for any mobile equipment, and reducing energy consumption via energy management in 3G LTE user equipment (UE will be essential for the delivery of a variety of services. Discontinuous transmission (DTX and reception (DRX have been designed to facilitate power management, but they can provide energy savings only via proper tuning. Relevant work in the literature mainly pertains only to discontinuous reception mode (DRX for downlink data. However, today’s increasingly powerful UEs can generate and upload significant amount of data. This paper proposes an energy management framework applicable to both discontinuous transmission (DTX and DRX power saving modes. In particular, in DTX mode it can reduce UE energy consumption for uplink intensive applications like telemedicine or social networking. The proposed novel energy management framework is based on jointly using a-priori analytical evaluation of a M/G/1/K finite uplink queue system for mixed traffic with an optimized DTX/DRX algorithm. DTX mode is modeled by an expression, through which the impact of quality of service (QoS parameters on the UE’s mean energy consumption for uplink transfer is determined. The model extracts and operates on the values computed for the M/G/1/K queue. Finally, a dynamic energy management algorithm for DRX/DTX modes is proposed for energy consumption optimization based on an integrated Analytical Hierarchy Process (AHP and Grey Relational Analysis (GRA. Analytical evaluation has shown that using our algorithm to tune DTX can achieve 49-73% energy saving over not using DTX.

  17. OPTIMIZATION OF ADVANCED FILTER SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    R.A. Newby; G.J. Bruck; M.A. Alvin; T.E. Lippert

    1998-04-30

    Reliable, maintainable and cost effective hot gas particulate filter technology is critical to the successful commercialization of advanced, coal-fired power generation technologies, such as IGCC and PFBC. In pilot plant testing, the operating reliability of hot gas particulate filters have been periodically compromised by process issues, such as process upsets and difficult ash cake behavior (ash bridging and sintering), and by design issues, such as cantilevered filter elements damaged by ash bridging, or excessively close packing of filtering surfaces resulting in unacceptable pressure drop or filtering surface plugging. This test experience has focused the issues and has helped to define advanced hot gas filter design concepts that offer higher reliability. Westinghouse has identified two advanced ceramic barrier filter concepts that are configured to minimize the possibility of ash bridge formation and to be robust against ash bridges should they occur. The ''inverted candle filter system'' uses arrays of thin-walled, ceramic candle-type filter elements with inside-surface filtering, and contains the filter elements in metal enclosures for complete separation from ash bridges. The ''sheet filter system'' uses ceramic, flat plate filter elements supported from vertical pipe-header arrays that provide geometry that avoids the buildup of ash bridges and allows free fall of the back-pulse released filter cake. The Optimization of Advanced Filter Systems program is being conducted to evaluate these two advanced designs and to ultimately demonstrate one of the concepts in pilot scale. In the Base Contract program, the subject of this report, Westinghouse has developed conceptual designs of the two advanced ceramic barrier filter systems to assess their performance, availability and cost potential, and to identify technical issues that may hinder the commercialization of the technologies. A plan for the Option I, bench

  18. Throughput-Based Traffic Steering in LTE-Advanced HetNet Deployments

    DEFF Research Database (Denmark)

    Gimenez, Lucas Chavarria; Kovacs, Istvan Z.; Wigard, Jeroen;

    2015-01-01

    The objective of this paper is to propose traffic steering solutions that aim at optimizing the end-user throughput. Two different implementations of an active mode throughput-based traffic steering algorithm for Heterogeneous Networks (HetNet) are introduced. One that always forces handover of the...

  19. An Efficient Detection Technique for Optimization of Network Traffic

    Directory of Open Access Journals (Sweden)

    Rajesh Kumar Ahirwar

    2011-02-01

    Full Text Available Network operators often need to deal with events that compromise their networks. One approach to find these events is to monitor the aggregate traffic in one or several network links and then look for significant deviations from some statistical model of normal behavior. This problem, known as traffic anomaly diagnosis, involves two steps: anomaly detection and root cause analysis. Anomaly detection methods have to define first what constitutes normal traffic behavior. Given the large variability in Internet traffic behavior, current techniques learn their parametric models from traces that are assumed to contain no anomalies. Besides the computational overhead of periodically re-training the model, real traces are never guaranteed to be anomaly-free; anomalies in the training data can contaminate the detector’s definition of normal traffic behavior. Another problem with current anomaly detectors is that, by aggregating traffic before detection, they lose information about which specific flows cause the anomaly. Root cause analysis is the process of recovering this information, by going back to the original traffic traces looking for events that could explain the alarm. Currently, there are few automated techniques that can help with root cause analysis; operators often rely on ad-hoc manual procedures, which are both time-consuming and error-prone. In a large network with hundreds of links, the number of events that can trigger alarms may easily overload the Network Operations Center, making anomaly detection tools useless. In this thesis we design an anomaly diagnosis system (i.e., detection and root cause analysis that exposes a broad range of anomalies and automatically explains their causes. We design an anomaly detection method that uses a non-parametric model of normal traffic behavior, and thus is simple to compute and immune to data contamination. It also makes it easier to identify the flows responsible for an anomaly. Second, we

  20. Overcoming the Pigou-Downs Paradox Using Advanced Traffic Signal Control

    Science.gov (United States)

    Fowdur, S. C.; Rughooputh, S. D. D. V.

    2013-06-01

    Expansion of a road network has often been observed to cause more congestion and has led researchers to the formulation of traffic paradoxes such as the Pigou-Downs and the Braess paradoxes. In this paper, we present an application of advanced traffic signal control (ATSC) to overcome the Pigou-Downs paradox. Port Louis, the capital city of Mauritius is used to investigate the effect of using a harbor bridge to by-pass the city center. Using traffic cellular automata (TCA) simulations it has been shown how, if traffic is only gradually deviated along the by-pass, an overall longer travel time and decreased flux would result. By making use of ATSC, which involves traffic lights that sense the number of vehicles accumulated in the queue, better travel times and fluxes are achieved.

  1. Second Annual Symposium On Advanced Traffic Management Systems (ATMS) And Advanced Traveler Information Systems (ATIS), November 5, 1990

    OpenAIRE

    Haldors, Bruce; Bozzini, Anna; May, Adolf D.

    1991-01-01

    The purpose of the Symposium on Advanced Traffic Management Systems (ATMS) and Advanced Traveler Information Systems (ATIS) was to allow researchers involved in ATM/ATIS work to become familiar with other research in those areas in the state of California. This document provides a brief summary outlining the presentations made at the symposium.

  2. Symmetry breaking in optimal timing of traffic signals on an idealized two-way street

    Science.gov (United States)

    Panaggio, Mark J.; Ottino-Löffler, Bertand J.; Hu, Peiguang; Abrams, Daniel M.

    2013-09-01

    Simple physical models based on fluid mechanics have long been used to understand the flow of vehicular traffic on freeways; analytically tractable models of flow on an urban grid, however, have not been as extensively explored. In an ideal world, traffic signals would be timed such that consecutive lights turned green just as vehicles arrived, eliminating the need to stop at each block. Unfortunately, this “green-wave” scenario is generally unworkable due to frustration imposed by competing demands of traffic moving in different directions. Until now this has typically been resolved by numerical simulation and optimization. Here, we develop a theory for the flow in an idealized system consisting of a long two-way road with periodic intersections. We show that optimal signal timing can be understood analytically and that there are counterintuitive asymmetric solutions to this signal coordination problem. We further explore how these theoretical solutions degrade as traffic conditions vary and automotive density increases.

  3. Symmetry breaking in optimal timing of traffic signals on an idealized two-way street

    CERN Document Server

    Panaggio, Mark J; Hu, Peiguang; Abrams, Daniel M

    2013-01-01

    Simple physical models based on fluid mechanics have long been used to understand the flow of vehicular traffic on freeways; analytically tractable models of flow on an urban grid, however, have not been as extensively explored. In an ideal world, traffic signals would be timed such that consecutive lights turned green just as vehicles arrived, eliminating the need to stop at each block. Unfortunately, this "green wave" scenario is generally unworkable due to frustration imposed by competing demands of traffic moving in different directions. Until now this has typically been resolved by numerical simulation and optimization. Here, we develop a theory for the flow in an idealized system consisting of a long two-way road with periodic intersections. We show that optimal signal timing can be understood analytically and that there are counter-intuitive asymmetric solutions to this signal coordination problem. We further explore how these theoretical solutions degrade as traffic conditions vary and automotive dens...

  4. Operational model for vessel traffic using optimal control and calibration

    OpenAIRE

    Shu, Y; Daamen, W.; Ligteringen, H.; Hoogendoorn, S.P.

    2015-01-01

    Due to the ever-increasing economic globalization, the scale of transportation through ports and waterways has increased sharply. As the capacity of maritime infrastructure in ports and inland waterways is limited, it is important to simulate vessel behavior to balance safety and capacity in restricted waterways. Currently many existing vessel simulation models focus mainly on vessel dynamics and maritime traffic in the open ocean. These models are, however, inapplicable to simulating vessel ...

  5. Traffic Patrol Service Platform Scheduling and Containment Optimization Strategy

    Science.gov (United States)

    Wang, Tiane; Niu, Taiyang; Wan, Baocheng; Li, Jian

    This article is based on the traffic and patrol police service platform settings and scheduling, in order to achieve the main purpose of rapid containment for the suspect in an emergency event. Proposing new boundary definition based on graph theory, using 0-1 programming, Dijkstra algorithm, the shortest path tree (SPT) and some of the related knowledge establish a containment model. Finally, making a combination with a city-specific data and using this model obtain the best containment plan.

  6. Toward an optimal convolutional neural network for traffic sign recognition

    Science.gov (United States)

    Habibi Aghdam, Hamed; Jahani Heravi, Elnaz; Puig, Domenec

    2015-12-01

    Convolutional Neural Networks (CNN) beat the human performance on German Traffic Sign Benchmark competition. Both the winner and the runner-up teams trained CNNs to recognize 43 traffic signs. However, both networks are not computationally efficient since they have many free parameters and they use highly computational activation functions. In this paper, we propose a new architecture that reduces the number of the parameters 27% and 22% compared with the two networks. Furthermore, our network uses Leaky Rectified Linear Units (ReLU) as the activation function that only needs a few operations to produce the result. Specifically, compared with the hyperbolic tangent and rectified sigmoid activation functions utilized in the two networks, Leaky ReLU needs only one multiplication operation which makes it computationally much more efficient than the two other functions. Our experiments on the Gertman Traffic Sign Benchmark dataset shows 0:6% improvement on the best reported classification accuracy while it reduces the overall number of parameters 85% compared with the winner network in the competition.

  7. Optimization strategy for and structural properties of traffic efficiency under bounded information accessibility

    Science.gov (United States)

    Sanghyun, Ahn; Seungwoong, Ha; Kim, Soo Yong

    2016-06-01

    A vital challenge for many socioeconomic systems is determining the optimum use of limited information. Traffic systems, wherein the range of resources is limited, are a particularly good example of this challenge. Based on bounded information accessibility in terms of, for example, high costs or technical limitations, we develop a new optimization strategy to improve the efficiency of a traffic system with signals and intersections. Numerous studies, including the study by Chowdery and Schadschneider (whose method we denote by ChSch), have attempted to achieve the maximum vehicle speed or the minimum wait time for a given traffic condition. In this paper, we introduce a modified version of ChSch with an independently functioning, decentralized control system. With the new model, we determine the optimization strategy under bounded information accessibility, which proves the existence of an optimal point for phase transitions in the system. The paper also provides insight that can be applied by traffic engineers to create more efficient traffic systems by analyzing the area and symmetry of local sites. We support our results with a statistical analysis using empirical traffic data from Seoul, Korea.

  8. The Wireless Sensor Networks Base Layout and Density Optimization Oriented towards Traffic Information Collection

    Directory of Open Access Journals (Sweden)

    Musong Gu

    2015-01-01

    Full Text Available Wireless sensor networks (WSN are applied in Intelligent Transport System for data collection. For the low redundancy rate of the wireless sensor networks nodes of traffic information collection, the senor nodes should be deployed reasonably for the WSN nodes to work effectively, and, thus, the base network structure and the density optimization of the sensor network are one of the main problems of WSN application. This paper establishes the wireless sensor networks design optimization model oriented to the traffic information collection, solving the design optimization model with the chemical reaction optimization (CRO algorithm. The experimental results show that CRO algorithm outperforms the traditional particle swarm optimization (PSO in solving the wireless sensor network design optimization oriented to the traffic information collection, capable of optimizing the wireless sensor network deployment of traffic information collection to contribute to the great improvement of the comprehensive value of the network performance. The reasonable design of the wireless sensor network nodes has great significance for the information collection, post-maintenance-and-extension, and cost saving of a monitoring system.

  9. Optimal Time Advance In Terminal Area Arrivals: Throughput vs. Fuel Savings

    Science.gov (United States)

    Sadovsky, Alexander V .; Swenson, Harry N.; Haskell, William B.; Rakas, Jasenka

    2011-01-01

    The current operational practice in scheduling air traffic arriving at an airport is to adjust flight schedules by delay, i.e. a postponement of an aircrafts arrival at a scheduled location, to manage safely the FAA-mandated separation constraints between aircraft. To meet the observed and forecast growth in traffic demand, however, the practice of time advance (speeding up an aircraft toward a scheduled location) is envisioned for future operations as a practice additional to delay. Time advance has two potential advantages. The first is the capability to minimize, or at least reduce, the excess separation (the distances between pairs of aircraft immediately in-trail) and thereby to increase the throughput of the arriving traffic. The second is to reduce the total traffic delay when the traffic sample is below saturation density. A cost associated with time advance is the fuel expenditure required by an aircraft to speed up. We present an optimal control model of air traffic arriving in a terminal area and solve it using the Pontryagin Maximum Principle. The admissible controls allow time advance, as well as delay, some of the way. The cost function reflects the trade-off between minimizing two competing objectives: excess separation (negatively correlated with throughput) and fuel burn. A number of instances are solved using three different methods, to demonstrate consistency of solutions.

  10. Day-to-day evolution of the traffic network with Advanced Traveler Information System

    International Nuclear Information System (INIS)

    Highlights: → We develop a dynamical system with Advanced Travelers Information System (ATIS). → We use the dynamical system to study stability of the traffic network with ATIS. → It is found that some periodic attractors appear in some cases. → A road pricing is implemented to alleviate the instability of the traffic network with ATIS. - Abstract: Since the notion of user equilibrium (UE) was proposed by Wardrop , it has become a cornerstone for traffic assignment analysis. But, it is not sufficient to only ask whether equilibrium exists or not; it is equally important to ask whether and how the system can achieve equilibrium. Meanwhile, stability is an important performance in the sense that if equilibrium is unsustainable, both the equilibrium and the trajectory are sensitive to disturbances, even a small perturbation will result in the system evolution away from the equilibrium point. These incentive a growing interest in day-to-day dynamics. In this paper, we develop a dynamical system with Advanced Traveler Information System (ATIS) and study the stability of the network with ATIS. A simple network is used to simulate the model, and the results show that there exist periodic attractors in the traffic network in some cases (for example, the market penetration level of ATIS is 0.25 and traffic demand is 2 unit). It is found that the logit parameter of the dynamical model and the traffic demand can also affect the stability of the traffic network. More periodic attractors appear in the system when the traffic demand is large and the low logit parameter can delay the appearance of periodic attractors. By simulation, it can be concluded that if the range of the periodic attractors' domain of the simple network is known, the road pricing based on the range of the attraction domain is effective to alleviate the instability of the system.

  11. Optimizing aspects of pedestrian traffic in building designs

    KAUST Repository

    Rodriguez, Samuel

    2013-11-01

    In this work, we investigate aspects of building design that can be optimized. Architectural features that we explore include pillar placement in simple corridors, doorway placement in buildings, and agent placement for information dispersement in an evacuation. The metrics utilized are tuned to the specific scenarios we study, which include continuous flow pedestrian movement and building evacuation. We use Multidimensional Direct Search (MDS) optimization with an extreme barrier criteria to find optimal placements while enforcing building constraints. © 2013 IEEE.

  12. Hazardous Traffic Event Detection Using Markov Blanket and Sequential Minimal Optimization (MB-SMO).

    Science.gov (United States)

    Yan, Lixin; Zhang, Yishi; He, Yi; Gao, Song; Zhu, Dunyao; Ran, Bin; Wu, Qing

    2016-01-01

    The ability to identify hazardous traffic events is already considered as one of the most effective solutions for reducing the occurrence of crashes. Only certain particular hazardous traffic events have been studied in previous studies, which were mainly based on dedicated video stream data and GPS data. The objective of this study is twofold: (1) the Markov blanket (MB) algorithm is employed to extract the main factors associated with hazardous traffic events; (2) a model is developed to identify hazardous traffic event using driving characteristics, vehicle trajectory, and vehicle position data. Twenty-two licensed drivers were recruited to carry out a natural driving experiment in Wuhan, China, and multi-sensor information data were collected for different types of traffic events. The results indicated that a vehicle's speed, the standard deviation of speed, the standard deviation of skin conductance, the standard deviation of brake pressure, turn signal, the acceleration of steering, the standard deviation of acceleration, and the acceleration in Z (G) have significant influences on hazardous traffic events. The sequential minimal optimization (SMO) algorithm was adopted to build the identification model, and the accuracy of prediction was higher than 86%. Moreover, compared with other detection algorithms, the MB-SMO algorithm was ranked best in terms of the prediction accuracy. The conclusions can provide reference evidence for the development of dangerous situation warning products and the design of intelligent vehicles. PMID:27420073

  13. Hazardous Traffic Event Detection Using Markov Blanket and Sequential Minimal Optimization (MB-SMO)

    Science.gov (United States)

    Yan, Lixin; Zhang, Yishi; He, Yi; Gao, Song; Zhu, Dunyao; Ran, Bin; Wu, Qing

    2016-01-01

    The ability to identify hazardous traffic events is already considered as one of the most effective solutions for reducing the occurrence of crashes. Only certain particular hazardous traffic events have been studied in previous studies, which were mainly based on dedicated video stream data and GPS data. The objective of this study is twofold: (1) the Markov blanket (MB) algorithm is employed to extract the main factors associated with hazardous traffic events; (2) a model is developed to identify hazardous traffic event using driving characteristics, vehicle trajectory, and vehicle position data. Twenty-two licensed drivers were recruited to carry out a natural driving experiment in Wuhan, China, and multi-sensor information data were collected for different types of traffic events. The results indicated that a vehicle’s speed, the standard deviation of speed, the standard deviation of skin conductance, the standard deviation of brake pressure, turn signal, the acceleration of steering, the standard deviation of acceleration, and the acceleration in Z (G) have significant influences on hazardous traffic events. The sequential minimal optimization (SMO) algorithm was adopted to build the identification model, and the accuracy of prediction was higher than 86%. Moreover, compared with other detection algorithms, the MB-SMO algorithm was ranked best in terms of the prediction accuracy. The conclusions can provide reference evidence for the development of dangerous situation warning products and the design of intelligent vehicles. PMID:27420073

  14. Bandwidth Optimization in Centralized WLANs for Different Traffic Types

    Directory of Open Access Journals (Sweden)

    R. J. Haines

    2007-03-01

    Full Text Available Allocating bandwidth between different forms of coexisting traffic (such as web-browsing, streaming, and telephony within a wireless LAN is a challenging and interesting problem. Centralized coordination functions in wireless LANs offer several advantages over distributed approaches, having the benefit of a system overview at the controller, but obtaining a stable configuration of bandwidth allocation for the system is nontrivial. We present, review, and compare different mechanisms to achieve this end, and a number of different means of obtaining the configurations themselves. We describe an analytical model of the system under consideration and present two mathematical approaches to derive solutions for any system configuration and deployment, along with an adaptive feedback-based solution. We also describe a comprehensive simulation-based model for the problem, and a prototype that allows comparison of these approaches. Our investigations demonstrate that a self-adaptive dynamic approach far outperforms any static scheme, and that using a mathematical model to produce the configurations themselves confers several advantages.

  15. Bandwidth Optimization in Centralized WLANs for Different Traffic Types

    Directory of Open Access Journals (Sweden)

    Haines RJ

    2007-01-01

    Full Text Available Allocating bandwidth between different forms of coexisting traffic (such as web-browsing, streaming, and telephony within a wireless LAN is a challenging and interesting problem. Centralized coordination functions in wireless LANs offer several advantages over distributed approaches, having the benefit of a system overview at the controller, but obtaining a stable configuration of bandwidth allocation for the system is nontrivial. We present, review, and compare different mechanisms to achieve this end, and a number of different means of obtaining the configurations themselves. We describe an analytical model of the system under consideration and present two mathematical approaches to derive solutions for any system configuration and deployment, along with an adaptive feedback-based solution. We also describe a comprehensive simulation-based model for the problem, and a prototype that allows comparison of these approaches. Our investigations demonstrate that a self-adaptive dynamic approach far outperforms any static scheme, and that using a mathematical model to produce the configurations themselves confers several advantages.

  16. The Wireless Sensor Networks Base Layout and Density Optimization Oriented towards Traffic Information Collection

    OpenAIRE

    Musong Gu; Lei You; Jun Hu; Lintao Duan; Zhen Zuo

    2015-01-01

    Wireless sensor networks (WSN) are applied in Intelligent Transport System for data collection. For the low redundancy rate of the wireless sensor networks nodes of traffic information collection, the senor nodes should be deployed reasonably for the WSN nodes to work effectively, and, thus, the base network structure and the density optimization of the sensor network are one of the main problems of WSN application. This paper establishes the wireless sensor networks design optimization model...

  17. Optimal traffic control in highway transportation networks using linear programming

    KAUST Repository

    Li, Yanning

    2014-06-01

    This article presents a framework for the optimal control of boundary flows on transportation networks. The state of the system is modeled by a first order scalar conservation law (Lighthill-Whitham-Richards PDE). Based on an equivalent formulation of the Hamilton-Jacobi PDE, the problem of controlling the state of the system on a network link in a finite horizon can be posed as a Linear Program. Assuming all intersections in the network are controllable, we show that the optimization approach can be extended to an arbitrary transportation network, preserving linear constraints. Unlike previously investigated transportation network control schemes, this framework leverages the intrinsic properties of the Halmilton-Jacobi equation, and does not require any discretization or boolean variables on the link. Hence this framework is very computational efficient and provides the globally optimal solution. The feasibility of this framework is illustrated by an on-ramp metering control example.

  18. The benefits of advanced traffic management received by the urban users

    Directory of Open Access Journals (Sweden)

    Kristi Bombol

    2009-12-01

    Full Text Available Despite the flow fluctuations and increased traffic demand in Macedonian cities in the last fifteen years, Republic of Macedonia is one of those countries which still employ only the traditional systems of traffic management and control. A general call for “…something has to be done…” becomes obvious. The best practices have shown that this can be realized through unconventional solutions, i.e. by means of advanced traffic management (ATM. A very reasonable example of such a system is the vehicle actuated control system that we have found to be quite challenging to do our research. It was concluded that the overall intersection performance could be improved both by adequate inductive loop detector placement and by interaction with signal parameters.

  19. Quantitative explanation of circuit experiments and real traffic using the optimal velocity model

    Science.gov (United States)

    Nakayama, Akihiro; Kikuchi, Macoto; Shibata, Akihiro; Sugiyama, Yuki; Tadaki, Shin-ichi; Yukawa, Satoshi

    2016-04-01

    We have experimentally confirmed that the occurrence of a traffic jam is a dynamical phase transition (Tadaki et al 2013 New J. Phys. 15 103034, Sugiyama et al 2008 New J. Phys. 10 033001). In this study, we investigate whether the optimal velocity (OV) model can quantitatively explain the results of experiments. The occurrence and non-occurrence of jammed flow in our experiments agree with the predictions of the OV model. We also propose a scaling rule for the parameters of the model. Using this rule, we obtain critical density as a function of a single parameter. The obtained critical density is consistent with the observed values for highway traffic.

  20. Gis-Based Route Finding Using ANT Colony Optimization and Urban Traffic Data from Different Sources

    Science.gov (United States)

    Davoodi, M.; Mesgari, M. S.

    2015-12-01

    Nowadays traffic data is obtained from multiple sources including GPS, Video Vehicle Detectors (VVD), Automatic Number Plate Recognition (ANPR), Floating Car Data (FCD), VANETs, etc. All such data can be used for route finding. This paper proposes a model for finding the optimum route based on the integration of traffic data from different sources. Ant Colony Optimization is applied in this paper because the concept of this method (movement of ants in a network) is similar to urban road network and movements of cars. The results indicate that this model is capable of incorporating data from different sources, which may even be inconsistent.

  1. Combined Intra- and Inter-domain Traffic Engineering using Hot-Potato Aware Link Weights Optimization

    CERN Document Server

    Balon, Simon

    2008-01-01

    A well-known approach to intradomain traffic engineering consists in finding the set of link weights that minimizes a network-wide objective function for a given intradomain traffic matrix. This approach is inadequate because it ignores a potential impact on interdomain routing. Indeed, the resulting set of link weights may trigger BGP to change the BGP next hop for some destination prefixes, to enforce hot-potato routing policies. In turn, this results in changes in the intradomain traffic matrix that have not been anticipated by the link weights optimizer, possibly leading to degraded network performance. We propose a BGP-aware link weights optimization method that takes these effects into account, and even turns them into an advantage. This method uses the interdomain traffic matrix and other available BGP data, to extend the intradomain topology with external virtual nodes and links, on which all the well-tuned heuristics of a classical link weights optimizer can be applied. A key innovative asset of our ...

  2. Parameter optimization in AQM controller design to support TCP traffic

    Science.gov (United States)

    Yang, Wei; Yang, Oliver W.

    2004-09-01

    TCP congestion control mechanism has been widely investigated and deployed on Internet in preventing congestion collapse. We would like to employ modern control theory to specify quantitatively the control performance of the TCP communication system. In this paper, we make use of a commonly used performance index called the Integral of the Square of the Error (ISE), which is a quantitative measure to gauge the performance of a control system. By applying the ISE performance index into the Proportional-plus-Integral controller based on Pole Placement (PI_PP controller) for active queue management (AQM) in IP routers, we can further tune the parameters for the controller to achieve an optimum control minimizing control errors. We have analyzed the dynamic model of the TCP congestion control under this ISE, and used OPNET simulation tool to verify the derived optimized parameters of the controllers.

  3. Optimization of Traffic System using TCL Algorithm through FMSA and IMAC Agents

    Directory of Open Access Journals (Sweden)

    T.Karthikeyan , S.Sujatha

    2012-08-01

    Full Text Available Based on Agent Technology, Service Oriented Architecture and RFID,this paper puts forward a ‘real time paradigm’ traffic congestion control strategy in metropolitan cities. This strategy uses TCL algorithm in order to provide optimal traffic performance evaluation considering the parameter, velocity of vehicles by implementing RMI & SOAP interfaces. This building block of traffic and transportation system is more suited for the proposed mobile agents FMSA(Fixed Monitor Stationary Agent & IMAC(Interactive Mobile Agent for Client because this model works on the Agent technology that can be developed using Java and JADE Agent platform under dynamic changing environments. The developed FMSA & IMAC agents makes real time decisions for choosing the best path in road traffic network to avoid congestion by considering the parameters for optimization like mainly the velocity of vehicles in the existing lane. This paper also compares the experimental results obtained by the system before and after the implementation of FMSA & IMAC agents to prove the significant performance for finding the best path by confirming the better efficiency & scalability improvement of our framework.

  4. Optimal Airport Surface Traffic Planning Using Mixed-Integer Linear Programming

    Directory of Open Access Journals (Sweden)

    H. G. Visser

    2008-06-01

    Full Text Available We describe an ongoing research effort pertaining to the development of a surface traffic automation system that will help controllers to better coordinate surface traffic movements related to arrival and departure traffic. More specifically, we describe the concept for a taxi-planning support tool that aims to optimize the routing and scheduling of airport surface traffic in such a way as to deconflict the taxi plans while optimizing delay, total taxi-time, or some other airport efficiency metric. Certain input parameters related to resource demand, such as the expected landing times and the expected pushback times, are rather difficult to predict accurately. Due to uncertainty in the input data driving the taxi-planning process, the taxi-planning tool is designed such that it produces solutions that are robust to uncertainty. The taxi-planning concept presented herein, which is based on mixed-integer linear programming, is designed such that it is able to adapt to perturbations in these input conditions, as well as to account for failure in the actual execution of surface trajectories. The capabilities of the tool are illustrated in a simple hypothetical airport.

  5. Energy-Efficient Relay Selection and Optimal Relay Location in Cooperative Cellular Networks with Asymmetric Traffic

    CERN Document Server

    Yang, Wei; Sun, Wanlu

    2010-01-01

    Energy-efficient communication is an important requirement for mobile relay networks due to the limited battery power of user terminals. This paper considers energy-efficient relaying schemes through selection of mobile relays in cooperative cellular systems with asymmetric traffic. The total energy consumption per information bit of the battery-powered terminals, i.e., the mobile station (MS) and the relay, is derived in theory. In the Joint Uplink and Downlink Relay Selection (JUDRS) scheme we proposed, the relay which minimizes the total energy consumption is selected. Additionally, the energy-efficient cooperation regions are investigated, and the optimal relay location is found for cooperative cellular systems with asymmetric traffic. The results reveal that the MS-relay and the relay-base station (BS) channels have different influence over relay selection decisions for optimal energy-efficiency. Information theoretic analysis of the diversity-multiplexing tradeoff (DMT) demonstrates that the proposed sc...

  6. The fully actuated traffic control problem solved by global optimization and complementarity

    Science.gov (United States)

    Ribeiro, Isabel M.; de Lurdes de Oliveira Simões, Maria

    2016-02-01

    Global optimization and complementarity are used to determine the signal timing for fully actuated traffic control, regarding effective green and red times on each cycle. The average values of these parameters can be used to estimate the control delay of vehicles. In this article, a two-phase queuing system for a signalized intersection is outlined, based on the principle of minimization of the total waiting time for the vehicles. The underlying model results in a linear program with linear complementarity constraints, solved by a sequential complementarity algorithm. Departure rates of vehicles during green and yellow periods were treated as deterministic, while arrival rates of vehicles were assumed to follow a Poisson distribution. Several traffic scenarios were created and solved. The numerical results reveal that it is possible to use global optimization and complementarity over a reasonable number of cycles and determine with efficiency effective green and red times for a signalized intersection.

  7. Vehicular Traffic Optimization in VANETs: a Proposal for Nodes Re-routing and Congestion Reduction

    Directory of Open Access Journals (Sweden)

    Mauro Tropea

    2015-01-01

    Full Text Available Recently, vehicular networking has grown up in terms of interest and transmission capability, due to the possibility of exploiting the distributed communication paradigm in a mobile scenario, where moving nodes are represented by vehicles. In this paper, we focus our attention on the optimization of traffic flowing in a vehicular environment with vehicle-roadside capability. As shown in the next sections, the proposed idea exploits the information that is gathered by road-side units with the main aim of redirecting traffic flows (in terms of vehicles to less congested roads, with an overall system optimization, also in terms of Carbon Dioxide emissions reduction. A deep campaign of simulations has been carried out to give more effectiveness to our proposal.

  8. Analytical solutions of jam pattern formation on a ring for a class of optimal velocity traffic models

    DEFF Research Database (Denmark)

    Gaididei, Yuri Borisovich; Berkemer, Rainer; Caputo, Jean Guy;

    2009-01-01

    A follow-the-leader model of traffic flow on a closed loop is considered in the framework of the extended optimal velocity (OV) model where the driver reacts to both the following and the preceding car. Periodic wave train solutions that describe the formation of traffic congestion patterns are...

  9. VANET-based optimization of infotainment and traffic efficiency vehicular services

    OpenAIRE

    Gramaglia, Marco

    2012-01-01

    The design, standardization and future deployment of vehicular communications systems have been driven so far by safety applications. There are two more aspects of the vehicular networking that have increased their importance in the last years: infotainment and traffic efficiency, as they can improve drivers’ experience, making vehicular communications systems more attractive to end-users. In this thesis we propose optimization mechanisms for both types of vehicular services. Infotainment ser...

  10. Towards the Practical Implementation of Throughput-Optimal Traffic Engineering in Software Defined Networks

    OpenAIRE

    Cruzado Pérez, Laura

    2015-01-01

    Broadband Wireless Networking topics: 5G, wireless underground sensor networks, software defined networking The new emerging networking paradigm of Software Defined Networks, a solution that separates the network control plane from the data forwarding plane, has been the main focus of recently research works. Nevertheless, Traffic Engineering is an important problem to optimize the network performance, especially for a centralized controlled network such as the SDN, by dynamically analyzin...

  11. Application of reinforcement learning methods for optimization of traffic control on arterial roads

    OpenAIRE

    Marsetič, Rok

    2016-01-01

    Nowadays, society faces several traffic related problems, such as traffic jams, time loss, lower traffic safety, increased pollution, etc., especially in urban areas. This is caused by high traffic volumes, which often exceed the capacity of the road infrastructure, particularly in peak hours. A common way of managing traffic in urban areas is traffic light control, which plays a key role in traffic safety and efficiency. To reduce delays the traffic light controllers should adjust to changin...

  12. Human-system safety methods for development of advanced air traffic management systems

    International Nuclear Information System (INIS)

    The Idaho National Engineering and Environmental Laboratory (INEEL) is supporting the National Aeronautics and Space Administration in the development of advanced air traffic management (ATM) systems as part of the Advanced Air Transportation Technologies program. As part of this program INEEL conducted a survey of human-system safety methods that have been applied to complex technical systems, to identify lessons learned from these applications and provide recommendations for the development of advanced ATM systems. The domains that were surveyed included offshore oil and gas, commercial nuclear power, commercial aviation, and military. The survey showed that widely different approaches are used in these industries, and that the methods used range from very high-level, qualitative approaches to very detailed quantitative methods such as human reliability analysis (HRA) and probabilistic safety assessment (PSA). In addition, the industries varied widely in how effectively they incorporate human-system safety assessment in the design, development, and testing of complex technical systems. In spite of the lack of uniformity in the approaches and methods used, it was found that methods are available that can be combined and adapted to support the development of advanced air traffic management systems (author) (ml)

  13. Advanced Cogeneration Technology Economic Optimization Study (ACTEOS)

    Science.gov (United States)

    Nanda, P.; Ansu, Y.; Manuel, E. H., Jr.; Price, W. G., Jr.

    1980-01-01

    The advanced cogeneration technology economic optimization study (ACTEOS) was undertaken to extend the results of the cogeneration technology alternatives study (CTAS). Cost comparisons were made between designs involving advanced cogeneration technologies and designs involving either conventional cogeneration technologies or not involving cogeneration. For the specific equipment cost and fuel price assumptions made, it was found that: (1) coal based cogeneration systems offered appreciable cost savings over the no cogeneration case, while systems using coal derived liquids offered no costs savings; and (2) the advanced cogeneration systems provided somewhat larger cost savings than the conventional systems. Among the issues considered in the study included: (1) temporal variations in steam and electric demands; (2) requirements for reliability/standby capacity; (3) availability of discrete equipment sizes; (4) regional variations in fuel and electricity prices; (5) off design system performance; and (6) separate demand and energy charges for purchased electricity.

  14. Optimal Traffic Allocation for Multi-Stream Aggregation in Heterogeneous Networks

    DEFF Research Database (Denmark)

    Popovska Avramova, Andrijana; Iversen, Villy Bæk

    2015-01-01

    nature of radio access networks are considered as important factors for performance improvement by multi-stream aggregation. Therefore, in our model, the networks are represented by different queueing systems in order to indicate networks with opposite quality of service provisioning, capacity and delay...... variations. Furthermore, services with different traffic characteristics in terms of quality of service requirements are considered. The simulation results show the advantages of our scheme with respect to efficient increase in data rate and delay performance compared to traditional schemes.......This paper investigates an optimal traffic rate allocation method for multi-stream aggregation over heterogeneous networks that deals with effective integration of two or more heterogeneous links for improved data throughput and enhanced quality of experience. The heterogeneity and the dynamic...

  15. Optimal Traffic Allocation for Multi-Stream Aggregation in Heterogeneous Networks

    DEFF Research Database (Denmark)

    Popovska Avramova, Andrijana; Iversen, Villy Bæk

    2015-01-01

    This paper investigates an optimal traffic rate allocation method for multi-stream aggregation over heterogeneous networks that deals with effective integration of two or more heterogeneous links for improved data throughput and enhanced quality of experience. The heterogeneity and the dynamic...... nature of radio access networks are considered as important factors for performance improvement by multi-stream aggregation. Therefore, in our model, the networks are represented by different queueing systems in order to indicate networks with opposite quality of service provisioning, capacity and delay...

  16. Online Optimal Control of Connected Vehicles for Efficient Traffic Flow at Merging Roads

    Energy Technology Data Exchange (ETDEWEB)

    Rios-Torres, Jackeline [ORNL; Malikopoulos, Andreas [ORNL; Pisu, Pierluigi [Clemson University

    2015-01-01

    This paper addresses the problem of coordinating online connected vehicles at merging roads to achieve a smooth traffic flow without stop-and-go driving. We present a framework and a closed-form solution that optimize the acceleration profile of each vehicle in terms of fuel economy while avoiding collision with other vehicles at the merging zone. The proposed solution is validated through simulation and it is shown that coordination of connected vehicles can reduce significantly fuel consumption and travel time at merging roads.

  17. OPTIMIZATION OF URBAN MULTI-INTERSECTION TRAFFIC FLOW VIA Q-LEARNING

    OpenAIRE

    Yit Kwong Chin; Heng Jin Tham; N.S.V. Kameswara Rao; Nurmin Bolong; Kenneth Tze Kin Teo

    2013-01-01

    Congestions of the traffic flow within the urban traffic network have been a challenging task for all the urban developers. Many approaches have been introduced into the current system to solve the traffic congestion problems. Reconfiguration of the traffic signal timing plan has been carried out through implementation of different techniques. However, dynamic characteristics of the traffic flow increase the difficulties towards the ultimate solutions. Thus, traffic congestions still remain a...

  18. OPTIMIZATION OF ADVANCED FILTER SYSTEMS; TOPICAL

    International Nuclear Information System (INIS)

    Reliable, maintainable and cost effective hot gas particulate filter technology is critical to the successful commercialization of advanced, coal-fired power generation technologies, such as IGCC and PFBC. In pilot plant testing, the operating reliability of hot gas particulate filters have been periodically compromised by process issues, such as process upsets and difficult ash cake behavior (ash bridging and sintering), and by design issues, such as cantilevered filter elements damaged by ash bridging, or excessively close packing of filtering surfaces resulting in unacceptable pressure drop or filtering surface plugging. This test experience has focused the issues and has helped to define advanced hot gas filter design concepts that offer higher reliability. Westinghouse has identified two advanced ceramic barrier filter concepts that are configured to minimize the possibility of ash bridge formation and to be robust against ash bridges should they occur. The ''inverted candle filter system'' uses arrays of thin-walled, ceramic candle-type filter elements with inside-surface filtering, and contains the filter elements in metal enclosures for complete separation from ash bridges. The ''sheet filter system'' uses ceramic, flat plate filter elements supported from vertical pipe-header arrays that provide geometry that avoids the buildup of ash bridges and allows free fall of the back-pulse released filter cake. The Optimization of Advanced Filter Systems program is being conducted to evaluate these two advanced designs and to ultimately demonstrate one of the concepts in pilot scale. In the Base Contract program, the subject of this report, Westinghouse has developed conceptual designs of the two advanced ceramic barrier filter systems to assess their performance, availability and cost potential, and to identify technical issues that may hinder the commercialization of the technologies. A plan for the Option I, bench-scale test program has also been developed based

  19. Optimal Control and Coordination of Connected and Automated Vehicles at Urban Traffic Intersections

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yue J. [Boston University; Malikopoulos, Andreas [ORNL; Cassandras, Christos G. [Boston University

    2016-01-01

    We address the problem of coordinating online a continuous flow of connected and automated vehicles (CAVs) crossing two adjacent intersections in an urban area. We present a decentralized optimal control framework whose solution yields for each vehicle the optimal acceleration/deceleration at any time in the sense of minimizing fuel consumption. The solu- tion, when it exists, allows the vehicles to cross the intersections without the use of traffic lights, without creating congestion on the connecting road, and under the hard safety constraint of collision avoidance. The effectiveness of the proposed solution is validated through simulation considering two intersections located in downtown Boston, and it is shown that coordination of CAVs can reduce significantly both fuel consumption and travel time.

  20. System for Road Vehicle Energy Optimization Using Real Time Road and Traffic Information

    Directory of Open Access Journals (Sweden)

    Felipe Jiménez

    2014-06-01

    Full Text Available Nowadays, reducing the energy and fuel consumption of road vehicles is a key issue. Different strategies have been proposed. One of them is to promote Eco-driving behaviour among drivers. Most Eco-driving tips take into account only the road stretch where the vehicle is located. However, larger improvements could be achieved if information from subsequent stretches is used. The main objective of this work is to develop a system to warn the driver in real time of the optimal speed that should be maintained on every road segment in order to optimize the energy used and the fuel consumed while observing a time schedule. The system takes into account the road vertical profile, the fixed and variable speed limits and the traffic information retrieved using V2V and V2I communications. The system has been tested on real road sections with satisfactory results in fuel savings.

  1. Feasibility of a Networked Air Traffic Infrastructure Validation Environment for Advanced NextGen Concepts

    Science.gov (United States)

    McCormack, Michael J.; Gibson, Alec K.; Dennis, Noah E.; Underwood, Matthew C.; Miller,Lana B.; Ballin, Mark G.

    2013-01-01

    Abstract-Next Generation Air Transportation System (NextGen) applications reliant upon aircraft data links such as Automatic Dependent Surveillance-Broadcast (ADS-B) offer a sweeping modernization of the National Airspace System (NAS), but the aviation stakeholder community has not yet established a positive business case for equipage and message content standards remain in flux. It is necessary to transition promising Air Traffic Management (ATM) Concepts of Operations (ConOps) from simulation environments to full-scale flight tests in order to validate user benefits and solidify message standards. However, flight tests are prohibitively expensive and message standards for Commercial-off-the-Shelf (COTS) systems cannot support many advanced ConOps. It is therefore proposed to simulate future aircraft surveillance and communications equipage and employ an existing commercial data link to exchange data during dedicated flight tests. This capability, referred to as the Networked Air Traffic Infrastructure Validation Environment (NATIVE), would emulate aircraft data links such as ADS-B using in-flight Internet and easily-installed test equipment. By utilizing low-cost equipment that is easy to install and certify for testing, advanced ATM ConOps can be validated, message content standards can be solidified, and new standards can be established through full-scale flight trials without necessary or expensive equipage or extensive flight test preparation. This paper presents results of a feasibility study of the NATIVE concept. To determine requirements, six NATIVE design configurations were developed for two NASA ConOps that rely on ADS-B. The performance characteristics of three existing in-flight Internet services were investigated to determine whether performance is adequate to support the concept. Next, a study of requisite hardware and software was conducted to examine whether and how the NATIVE concept might be realized. Finally, to determine a business case

  2. OPTIMAL ANALYTICAL INSTRUMENTS IN THE FUNCTION OF ESTIMATION OF TOTAL TRAFFIC IN THE PORT OF RIJEKA

    OpenAIRE

    Juretić, Sandra; Cerović, Ljerka; Galović, Tomislav

    2013-01-01

    The subject of the analysis in this paper is traffic in the Port of Rijeka, the largest and the most significant Croatian port for domestic and international public, predominantly cargo traffic, whose role, considering numerous plans for comprehensive modernisation and revitalisation of the Rijeka traffic route and hypercomplex traffic system, gains additional significance in terms of its impact on the general prosperity of the Rijeka area and the entire Croatia. The research in this ...

  3. Optimizing Network Topology to Reduce Aggregate Traffic in Systems of Mobile Robots

    CERN Document Server

    Navaravong, Leenhapat; Pasiliao, Eduardo L; Barnette, Gregory L; Dixon, Warren E

    2011-01-01

    Systems of networked mobile robots, such as unmanned aerial or ground vehicles, will play important roles in future military and commercial applications. The communications for such systems will typically be over wireless links and may require that the robots form an ad hoc network and communicate on a peer-to-peer basis. In this paper, we consider the problem of optimizing the network topology to minimize the total traffic in a network required to support a given set of data flows under constraints on the amount of movement possible at each mobile robot. In this paper, we consider a subclass of this problem in which the initial and final topologies are trees, and the movement restrictions are given in terms of the number of edges in the graph that must be traversed. We develop algorithms to optimize the network topology while maintaining network connectivity during the topology reconfiguration process. Our topology reconfiguration algorithm uses the concept of prefix labelling and routing to move nodes throu...

  4. Optimized advanced stellarators of linked mirror type

    International Nuclear Information System (INIS)

    Various different advanced stellarator configurations of the linked mirror type (LIMAS) have been investigated which differ in the magnetic mirror ratio and twist on the magnetic axis. One configuration is presented in the following. The vacuum fields are given analytically by a finite set of Dommaschk potentials. The magnetic field properties weighed in the optimization procedure are: the residue R* of two reference fixed lines (where the pressure gradient is high) which start at Z = 0 in the two symmetry planes and have the same value of the twist ι; the associated aspect ratio A; the difference ΔF of the magnetic flux F = ∫ A.dx between these two closed field lines belonging to the same rational ι-value (A is a vector potential, x is the radius vector, the line integral is performed over each of the fixed field lines); the deficit of the Hamada condition that ∫dl/B should have the same value for these two fixed lines; a condition on the magnetic well (ΔV'/V'ax ||2/j2>1/2 of the Pfirsch-Schlueter current density; the deviation of contours of B = const from contours of Q ∫dU/B2 = const (U is the scalar potential). This condition has the effect that the particles see small variations of the magnetic field along their poloidal rotation. This favours small values of the ambipolar diffusion coefficients in the long mean free path regime. The implementation of this constraint uses a Fourier decomposition of the magnetic field strength along a closed field line with respect to Q. The corresponding Bessel inequality is used as a quadratic measure (PR) of the 'amount of independency' of the Fourier coefficients as the poloidal coordinate. Some of the quoted conditions are also applied at a pair of fixed lines in the boundary region. (author) 4 refs., 11 figs

  5. Developing an Onboard Traffic-Aware Flight Optimization Capability for Near-Term Low-Cost Implementation

    Science.gov (United States)

    Wing, David J.; Ballin, Mark G.; Koczo, Stefan, Jr.; Vivona, Robert A.; Henderson, Jeffrey M.

    2013-01-01

    The concept of Traffic Aware Strategic Aircrew Requests (TASAR) combines Automatic Dependent Surveillance Broadcast (ADS-B) IN and airborne automation to enable user-optimal in-flight trajectory replanning and to increase the likelihood of Air Traffic Control (ATC) approval for the resulting trajectory change request. TASAR is designed as a near-term application to improve flight efficiency or other user-desired attributes of the flight while not impacting and potentially benefiting ATC. Previous work has indicated the potential for significant benefits for each TASAR-equipped aircraft. This paper will discuss the approach to minimizing TASAR's cost for implementation and accelerating readiness for near-term implementation.

  6. Aerodynamic optimization studies on advanced architecture computers

    Science.gov (United States)

    Chawla, Kalpana

    1995-01-01

    The approach to carrying out multi-discipline aerospace design studies in the future, especially in massively parallel computing environments, comprises of choosing (1) suitable solvers to compute solutions to equations characterizing a discipline, and (2) efficient optimization methods. In addition, for aerodynamic optimization problems, (3) smart methodologies must be selected to modify the surface shape. In this research effort, a 'direct' optimization method is implemented on the Cray C-90 to improve aerodynamic design. It is coupled with an existing implicit Navier-Stokes solver, OVERFLOW, to compute flow solutions. The optimization method is chosen such that it can accomodate multi-discipline optimization in future computations. In the work , however, only single discipline aerodynamic optimization will be included.

  7. Urban Road Network Structure Optimization Method Based on Traffic Safety%基于交通安全的城市路网结构优化方法

    Institute of Scientific and Technical Information of China (English)

    龙雪琴; 关宏志

    2012-01-01

    考虑城市交通事故与道路网结构的关系,结合交通事故导致的时间延误,提出了基于交通安全的城市路网结构优化方法.首先分析了不同等级道路之间的衔接方式对出行者选择路径行为的影响,总结了交通事故的影响因素.然后在此基础上提出了基于交通安全的路网构造原则,建立了以路网安全度最大为目标的路网结构模型,并通过求解模型确定各路段的道路等级,得到安全度和结构不同的若干个路网.通过考虑交通事故时间延误情况下,进行随机均衡分配,得到路网各路段的交通量,并计算各路网的交通事故次数.最后提出了路网的安全性评价指标,分析交通事故次数和路网结构指标的关系,提出了考虑安全性的路网结构优化措施,并用实例验证了优化措施的有效性.%Considered the relationship between urban traffic accidents and road network structure, combined with traffic accident delay, an urban road network structure optimization method based on traffic safety was advanced. At first, the influence of joining style of different grade roads on route choosing behaviors of travelers was analyzed, and influencing factors of traffic accidents were summarized. Based on which, road network constructing principles based on traffic safety were advanced, and a road network structure model with the largest safety degree as the goal was established. The road sections' grade was determined through solving the model, and several road networks with different safety degrees and structures were got. Then, a random equilibrium distribution method was used to determine all sections' traffic volumes considering the traffic accident delay, and the networks' accidents were calculated. At last, the network security evaluation indexes were proposed, the relation between accidents and network structure indexes were analyzed, the measures of road network structure optimization considering safety were

  8. A Critical Survey of Optimization Models for Tactical and Strategic Aspects of Air Traffic Flow Management

    Science.gov (United States)

    Bertsimas, Dimitris; Odoni, Amedeo

    1997-01-01

    This document presents a critical review of the principal existing optimization models that have been applied to Air Traffic Flow Management (TFM). Emphasis will be placed on two problems, the Generalized Tactical Flow Management Problem (GTFMP) and the Ground Holding Problem (GHP), as well as on some of their variations. To perform this task, we have carried out an extensive literature review that has covered more than 40 references, most of them very recent. Based on the review of this emerging field our objectives were to: (i) identify the best available models; (ii) describe typical contexts for applications of the models; (iii) provide illustrative model formulations; and (iv) identify the methodologies that can be used to solve the models. We shall begin our presentation below by providing a brief context for the models that we are reviewing. In Section 3 we shall offer a taxonomy and identify four classes of models for review. In Sections 4, 5, and 6 we shall then review, respectively, models for the Single-Airport Ground Holding Problem, the Generalized Tactical FM P and the Multi-Airport Ground Holding Problem (for the definition of these problems see Section 3 below). In each section, we identify the best available models and discuss briefly their computational performance and applications, if any, to date. Section 7 summarizes our conclusions about the state of the art.

  9. Advanced Aerostructural Optimization Techniques for Aircraft Design

    Directory of Open Access Journals (Sweden)

    Yingtao Zuo

    2015-01-01

    Full Text Available Traditional coupled aerostructural design optimization (ASDO of aircraft based on high-fidelity models is computationally expensive and inefficient. To improve the efficiency, the key is to predict aerostructural performance of the aircraft efficiently. The cruise shape of the aircraft is parameterized and optimized in this paper, and a methodology named reverse iteration of structural model (RISM is adopted to get the aerostructural performance of cruise shape efficiently. A new mathematical explanation of RISM is presented in this paper. The efficiency of RISM can be improved by four times compared with traditional static aeroelastic analysis. General purpose computing on graphical processing units (GPGPU is adopted to accelerate the RISM further, and GPU-accelerated RISM is constructed. The efficiency of GPU-accelerated RISM can be raised by about 239 times compared with that of the loosely coupled aeroelastic analysis. Test shows that the fidelity of GPU-accelerated RISM is high enough for optimization. Optimization framework based on Kriging model is constructed. The efficiency of the proposed optimization system can be improved greatly with the aid of GPU-accelerated RISM. An unmanned aerial vehicle (UAV is optimized using this framework and the range is improved by 4.67% after optimization, which shows effectiveness and efficiency of this framework.

  10. Advanced Topology Optimization Methods for Conceptual Architectural Design

    DEFF Research Database (Denmark)

    Aage, Niels; Amir, Oded; Clausen, Anders;

    2015-01-01

    This paper presents a series of new, advanced topology optimization methods, developed specifically for conceptual architectural design of structures. The proposed computational procedures are implemented as components in the framework of a Grasshopper plugin, providing novel capacities in...

  11. Some advances in tensor analysis and polynomial optimization

    OpenAIRE

    Li, Zhening; Ling, Chen; Wang, Yiju; Yang, Qingzhi

    2014-01-01

    Tensor analysis (also called as numerical multilinear algebra) mainly includes tensor decomposition, tensor eigenvalue theory and relevant algorithms. Polynomial optimization mainly includes theory and algorithms for solving optimization problems with polynomial objects functions under polynomial constrains. This survey covers the most of recent advances in these two fields. For tensor analysis, we introduce some properties and algorithms concerning the spectral radius of nonnegative tensors'...

  12. Advanced Topology Optimization Methods for Conceptual Architectural Design

    DEFF Research Database (Denmark)

    Aage, Niels; Amir, Oded; Clausen, Anders;

    2014-01-01

    This paper presents a series of new, advanced topology optimization methods, developed specifically for conceptual architectural design of structures. The proposed computational procedures are implemented as components in the framework of a Grasshopper plugin, providing novel capacities in...... frames are implemented. The developed procedures allow for the exploration of new territories in optimization of architectural structures, and offer new methodological strategies for bridging conceptual gaps between optimization and architectural practice....

  13. Multilevel Control & Optimization of Future Air Traffic Systems via Managem Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Controlling air traffic on all temporal and spatial scales – from a single aircraft to the entire airspace – can be formally stated as a dynamic,...

  14. Strategic Planning in Air Traffic Control as a Multi-objective Stochastic Optimization Problem

    OpenAIRE

    Marceau, Gaétan; Savéant, Pierre; Schoenauer, Marc

    2013-01-01

    With the objective of handling the airspace sector congestion subject to continuously growing air traffic, we suggest to create a collaborative working plan during the strategic phase of air traffic control. The plan obtained via a new decision support tool presented in this article consists in a schedule for controllers, which specifies time of overflight on the different waypoints of the flight plans. In order to do it, we believe that the decision-support tool shall model directly the unce...

  15. Advances in optimal routing through computer networks

    Science.gov (United States)

    Paz, I. M.

    1977-01-01

    The optimal routing problem is defined. Progress in solving the problem during the previous decade is reviewed, with special emphasis on technical developments made during the last few years. The relationships between the routing, the throughput, and the switching technology used are discussed and their future trends are reviewed. Economic aspects are also briefly considered. Modern technical approaches for handling the routing problems and, more generally, the flow control problems are reviewed.

  16. Glovebox Advanced Casting System Casting Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Fielding, Randall Sidney [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-03-01

    Casting optimization in the GACS included three broad areas; casting of U-10Zr pins, incorporation of an integral FCCI barrier, and development of a permanent crucible coating. U-10Zr casting was improved over last year’s results by modifying the crucible design to minimize contact with the colder mold. Through these modifications casting of a three pin batch was successful. Incorporation of an integral FCCI barrier also was optimized through furnace chamber pressure changes during the casting cycle to reduce gas pressures in the mold cavities which led to three full length pins being cast which incorporated FCCI barriers of three different thicknesses. Permanent crucible coatings were tested against a base case; 1500°C for 10 minutes in a U-20Pu-10Zr molten alloy. None of the candidate coating materials showed evidence of failure upon initial visual examination. In all areas of work a large amount of characterization will be needed to fully determine the effects of the optimization activities. The characterization activities and future work will occur next year.

  17. Radiation protection optimization. Advances in practical implementation

    International Nuclear Information System (INIS)

    Within the Community, protection against the dangers of ionizing radiation is regulated in conformity with the provisions of two Council Directives. One is of general application for all activities involving a hazard arising from ionizing radiation and lays down the basic safety standards for the health protection of the general public and workers against the dangers of ionizing radiation. The other is derived from the abovementioned one and lays down the basic measures for the radiation protection of persons undergoing medical examination or treatment. The Commission, in collaboration with the Spanish Ministerio de Sanidad y Consumo, the Consejo de Seguridad Nuclear and the Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas, organized on 12, 13 and 14 September 1988 in Madrid, the third scientific seminar on the optimization principle (Alara) which is a key element of the two abovementioned Council Directives. The seminar allowed an analysis of the progress made since the previous seminars of 1979 and 1983, in the practical implementation of the optimization principle, in relation to the design and operation of nuclear and industrial installations, natural radioactivity, medical practices and countermeasures. The report contains the 20 original contributions presented and some general considerations on the results of the seminar

  18. Antennas Designed for Advanced Communications for Air Traffic Management (AC/ATM) Project

    Science.gov (United States)

    Zakrajsek, Robert J.

    2000-01-01

    The goal of the Advanced Communications for Air Traffic Management (AC/ATM) Project at the NASA Glenn Research Center at Lewis Field is to enable a communications infrastructure that provides the capacity, efficiency, and flexibility necessary to realize a mature free-flight environment. The technical thrust of the AC/ATM Project is targeted at the design, development, integration, test, and demonstration of enabling technologies for global broadband aeronautical communications. Since Ku-band facilities and equipment are readily available, one of the near-term demonstrations involves a link through a Kuband communications satellite. Two conformally mounted antennas will support the initial AC/ATM communications links. Both of these are steered electronically through monolithic microwave integrated circuit (MMIC) amplifiers and phase shifters. This link will be asymmetrical with the downlink to the aircraft (mobile vehicle) at a throughput rate of greater than 1.5 megabits per second (Mbps), whereas the throughput rate of the uplink from the aircraft will be greater than 100 kilobits per second (kbps). The data on the downlink can be narrow-band, wide-band, or a combination of both, depending on the requirements of the experiment. The AC/ATM project is purchasing a phased-array Ku-band transmitting antenna for the uplink from the test vehicle. Many Ku-band receiving antennas have been built, and one will be borrowed for a short time to perform the initial experiments at the NASA Glenn Research Center at Lewis Field. The Ku-band transmitting antenna is a 254-element MMIC phased-array antenna being built by Boeing Phantom Works. Each element can radiate 100 mW. The antenna is approximately 43-cm high by 24-cm wide by 3.3-cm thick. It can be steered beyond 60 from broadside. The beamwidth varies from 6 at broadside to 12 degrees at 60 degrees, which is typical of phased-array antennas. When the antenna is steered to 60 degrees, the beamwidth will illuminate

  19. Search Engine Optimization Case St.Lapland : Creating a Plan to Increase the Traffic Volume on the Website

    OpenAIRE

    Calderón Martínez, Ester

    2013-01-01

    The aim of this thesis was the creation of a Search Engine Optimization Plan (SEO Plan) for the commissioner, St.Lapland, a tourist services provider located in Kuusamo Finland. The plan was hoping to improve the visibility of the website in search en-gines, focusing especially in Google.com as it is the major search engine in the Web and the preferred tool of the users for information gathering. By im-proving the visibility of the website it was expected an increase on traffic and theref...

  20. Advances in bio-inspired computing for combinatorial optimization problems

    CERN Document Server

    Pintea, Camelia-Mihaela

    2013-01-01

    Advances in Bio-inspired Combinatorial Optimization Problems' illustrates several recent bio-inspired efficient algorithms for solving NP-hard problems.Theoretical bio-inspired concepts and models, in particular for agents, ants and virtual robots are described. Large-scale optimization problems, for example: the Generalized Traveling Salesman Problem and the Railway Traveling Salesman Problem, are solved and their results are discussed.Some of the main concepts and models described in this book are: inner rule to guide ant search - a recent model in ant optimization, heterogeneous sensitive a

  1. Optimal Advanced Credit Releases in Ecosystem Service Markets

    Science.gov (United States)

    BenDor, Todd K.; Guo, Tianshu; Yates, Andrew J.

    2014-03-01

    Ecosystem service markets are popular policy tools for ecosystem protection. Advanced credit releases are an important factor affecting the supply side of ecosystem markets. Under an advanced credit release policy, regulators give ecosystem suppliers a fraction of the total ecosystem credits generated by a restoration project before it is verified that the project actually achieves the required ecological thresholds. In spite of their prominent role in ecosystem markets, there is virtually no regulatory or research literature on the proper design of advanced credit release policies. Using U.S. aquatic ecosystem markets as an example, we develop a principal-agent model of the behavior of regulators and wetland/stream mitigation bankers to determine and explore the optimal degree of advance credit release. The model highlights the tension between regulators' desire to induce market participation, while at the same time ensuring that bankers successfully complete ecological restoration. Our findings suggest several simple guidelines for strengthening advanced credit release policy.

  2. Optimal proportion of studded tyres in traffic flow to prevent polishing of an icy road.

    Science.gov (United States)

    Tuononen, Ari J; Sainio, Panu

    2014-04-01

    Studded tyres can significantly wear the road surface and increase particle emissions from the road surface, which has a negative impact on air quality in urban areas. However, road wear might have a positive aspect by roughening the road surface and thus preventing polishing. As a consequence, other vehicles than the ones using studded tyres might also benefit from the usage of studded tyres. The impact of the proportion of studded tyres in the traffic flow on the tyre-ice friction coefficient was studied with a fleet of real cars in a closed environment under strict procedural control. The results show that a proportion of 25-50% studded tyres in the traffic flow is enough to prevent ice from developing in a manner that is critically slippery for non-studded winter tyres. It was also observed that the visual appearance of the ice surface does not indicate if the ice has become more slippery or not. PMID:24445137

  3. Traffic-flow simulation

    OpenAIRE

    OMAHEN, ANDRAŽ

    2015-01-01

    This diploma thesis presents the behavior of program, which uses the traffic light enhanced transport network to simulate the traffic flow of vehicles that behave according to the IDM model. We upgraded the program to allow, for the given network, to optimize the traffic flow. Because of the overwhelming problem of road closures or their rearrangement, we added a graphical user interface with which a user can create or modify the road network to observe changes in traffic. The objective of...

  4. Fast and optimized methodology to generate road traffic emission inventories and their uncertainties

    Science.gov (United States)

    Blond, N.; Ho, B. Q.; Clappier, A.

    2012-04-01

    Road traffic emissions are one of the main sources of air pollution in the cities. They are also the main sources of uncertainties in the air quality numerical models used to forecast and define abatement strategies. Until now, the available models for generating road traffic emission always required a big effort, money and time. This inhibits decisions to preserve air quality, especially in developing countries where road traffic emissions are changing very fast. In this research, we developed a new model designed to fast produce road traffic emission inventories. This model, called EMISENS, combines the well-known top-down and bottom-up approaches to force them to be coherent. A Monte Carlo methodology is included for computing emission uncertainties and the uncertainty rate due to each input parameters. This paper presents the EMISENS model and a demonstration of its capabilities through an application over Strasbourg region (Alsace), France. Same input data as collected for Circul'air model (using bottom-up approach) which has been applied for many years to forecast and study air pollution by the Alsatian air quality agency, ASPA, are used to evaluate the impact of several simplifications that a user could operate . These experiments give the possibility to review older methodologies and evaluate EMISENS results when few input data are available to produce emission inventories, as in developing countries and assumptions need to be done. We show that same average fraction of mileage driven with a cold engine can be used for all the cells of the study domain and one emission factor could replace both cold and hot emission factors.

  5. Fuzzy portfolio optimization advances in hybrid multi-criteria methodologies

    CERN Document Server

    Gupta, Pankaj; Inuiguchi, Masahiro; Chandra, Suresh

    2014-01-01

    This monograph presents a comprehensive study of portfolio optimization, an important area of quantitative finance. Considering that the information available in financial markets is incomplete and that the markets are affected by vagueness and ambiguity, the monograph deals with fuzzy portfolio optimization models. At first, the book makes the reader familiar with basic concepts, including the classical mean–variance portfolio analysis. Then, it introduces advanced optimization techniques and applies them for the development of various multi-criteria portfolio optimization models in an uncertain environment. The models are developed considering both the financial and non-financial criteria of investment decision making, and the inputs from the investment experts. The utility of these models in practice is then demonstrated using numerical illustrations based on real-world data, which were collected from one of the premier stock exchanges in India. The book addresses both academics and professionals pursuin...

  6. Linear programming approach to traffic flow control - optimization on a horizon

    Czech Academy of Sciences Publication Activity Database

    Homolová, Jitka

    Hong Kong : Hong Kong Society for Transportation Studies, 2006 - (Wong, S.; Hau, T.; Wang, J.), s. 697-705 ISBN 978-988-98847-0-3; ISBN 988-98847-0-4. [International Conference of Hong Kong Society for Transportation Studies, Sustainable Transportation /11./. Hong Kong (HK), 09.12.2006-11.12.2006] R&D Projects: GA MDS 1F43A/003/120 Institutional research plan: CEZ:AV0Z10750506 Keywords : linear programming * traffic flow control * control on a horizon Subject RIV: BB - Applied Statistics, Operational Research

  7. Advanced optimal extraction for the Spitzer/IRS

    OpenAIRE

    Lebouteiller, V; Bernard-Salas, J.; Sloan, G. C.; Barry, D. J.

    2010-01-01

    We present new advances in the spectral extraction of point-like sources adapted to the Infrared Spectrograph onboard the Spitzer Space Telescope. For the first time, we created a super-sampled point spread function of the low-resolution modules. We describe how to use the point spread function to perform optimal extraction of a single source and of multiple sources within the slit. We also examine the case of the optimal extraction of one or several sources with a complex background. The new...

  8. Extending the horizons advances in computing, optimization, and decision technologies

    CERN Document Server

    Joseph, Anito; Mehrotra, Anuj; Trick, Michael

    2007-01-01

    Computer Science and Operations Research continue to have a synergistic relationship and this book represents the results of cross-fertilization between OR/MS and CS/AI. It is this interface of OR/CS that makes possible advances that could not have been achieved in isolation. Taken collectively, these articles are indicative of the state-of-the-art in the interface between OR/MS and CS/AI and of the high caliber of research being conducted by members of the INFORMS Computing Society. EXTENDING THE HORIZONS: Advances in Computing, Optimization, and Decision Technologies is a volume that presents the latest, leading research in the design and analysis of algorithms, computational optimization, heuristic search and learning, modeling languages, parallel and distributed computing, simulation, computational logic and visualization. This volume also emphasizes a variety of novel applications in the interface of CS, AI, and OR/MS.

  9. Optimizing advanced liquid metal reactors for burning actinides

    International Nuclear Information System (INIS)

    In this report, the process to design an Advanced Liquid Metal Reactor (ALMR) for burning the transuranic part of nuclear waste is discussed. The influence of design parameters on ALMR burner performance is studied and the results are incorporated in a design schedule for optimizing ALMRs for burning transuranics. This schedule is used to design a metallic and an oxide fueled ALMR burner to burn as much as possible transurancis. The two designs burn equally well. (orig.)

  10. Hybrid Ant Colony Optimization for Real-World Delivery Problems Based on Real Time and Predicted Traffic in Wide Area Road Network

    Directory of Open Access Journals (Sweden)

    Junichi Ochiai

    2014-02-01

    Full Text Available This paper presents a solution to real-world delive ry problems for home delivery services where a large number of roads exist in cities and the tra ffic on the roads rapidly changes with time. The methodology for finding the shortest-travel-tim e tour includes a hybrid meta-heuristic that combines ant colony optimization with Dijkstra’s al gorithm, a search technique that uses both real-time traffic and predicted traffic, and a way to use a real-world road map and measured traffic in Japan. Experimental results using a map of central Tokyo and historical traffic data indicate that the proposed method can find a better solution than conventional methods.

  11. Research on Application of Perceived QoS Guarantee through Infrastructure Specific Traffic Parameter Optimization

    Directory of Open Access Journals (Sweden)

    Vikram Jeet Singh

    2014-02-01

    Full Text Available The technological developments in the fields of multimedia clinical applications and communication networks require a specific analysis to increase the efficiency of network based healthcare services. In this work, we computed the optimum transmission parameter (data packet size for applications needed to guarantee the perceived quality of service in the proposed ubiquitous healthcare network. This has been carried out through NS2 based simulation of a state wide area network infrastructure implemented in Himachal Pradesh, a state with diverse geographical terrain situated in the Western Himalayan region of India. The various types of healthcare applications and services have been classified into different classes according to their perceived QOS requirements as per the guidelines in ITU report on network performance objectives. The infrastructure specific optimum values of data packet size for these QoS classes have been computed. Network based healthcare applications and services running on both TCP and UDP type of traffic have been presented in this paper.

  12. Assessing Traffic Accident Occurrence of Road Segments through an Optimized Decision Rule

    Directory of Open Access Journals (Sweden)

    Lu Ma

    2015-01-01

    Full Text Available Statistical models for estimating the safety status of transportation facilities have received great attention in the last two decades. These models also perform an important role in transportation safety planning as well as diagnoses of locations with high accident risks. However, the current methods largely rely on regression analyses and therefore they could ignore the multicollinearity characteristics of factors, which may provide additional information for enhancing the performance of forecasting models. This study seeks to develop more precise models for forecasting safety status as well as addressing the issue of multicollinearity of dataset. The proposed mathematical approach is indeed a discriminant analysis with respect to the goal of minimizing Bayes risks given multivariate distributions of factors. Based on this model, numerical analyses also perform with the application of a simulated dataset and an empirically observed dataset of traffic accidents in road segments. These examples essentially illustrate the process of Bayes risk minimization on predicating the safety status of road segments toward the objective of smallest misclassification rate. The paper finally concludes with a discussion of this methodology and several important avenues for future studies are also provided.

  13. Traffic Congestion and Accidents

    OpenAIRE

    Schrage, Andrea

    2006-01-01

    Obstructions caused by accidents can trigger or exacerbate traffic congestion. This paper derives the efficient traffic pattern for a rush hour with congestion and accidents and the corresponding road toll. Compared to the model without accidents, where the toll equals external costs imposed on drivers using the road at the same time, a new insight arises: An optimal toll also internalizes the expected increase in future congestion costs. Since accidents affect more drivers if traffic volumes...

  14. Analytic analysis of LTE/LTE-Advanced power saving and delay with bursty traffic

    OpenAIRE

    Bhamber, R. S.; Fowler, Scott; Braimiotis, C.; Mellouk, A.

    2013-01-01

    The 4G standard Long Term Evolution (LTE) has been developed for high-bandwidth mobile access for today’s data-heavy applications. However, these data-heavy applications require lots of battery power on the user equipment. To extend the user equipment battery lifetime, plus further support various services and large amount of data transmissions, the 3GPP standards for LTE/LTE-Advanced has adopted discontinuous reception (DRX). In this paper, we take an overview of various static/fixed DRX cyc...

  15. Trace Analysis of Driver Behavior on Traffic Violator by Using Big Data (Traffic Program in Korea

    Directory of Open Access Journals (Sweden)

    Lee, Jonghak

    2016-01-01

    Full Text Available This study aims to prove the effectiveness of traffic safety education program for traffic violators. Traffic violators who finished the traffic safety education programs were tracked down. In order to analyze the effectiveness of traffic safety education program, traffic violator’s data during ten-year period were used. This study analyzed how traffic violators changed their attitudes about traffic law abidance. Also predicted social benefits from traffic safety education program for traffic violators. Effectiveness of traffic accident prevention through traffic safety education program is approximately 93%. In terms of social benefits, it shows more than $12 billion Even though the effectiveness of traffic safety education program represents remarkable results, but this program is made for traffic violators who have already committed traffic offenses in the past. So in order to prevent traffic violations in advance, specific education program for potentially risky drivers is necessary.

  16. Environmental Monitoring Networks Optimization Using Advanced Active Learning Algorithms

    Science.gov (United States)

    Kanevski, Mikhail; Volpi, Michele; Copa, Loris

    2010-05-01

    The problem of environmental monitoring networks optimization (MNO) belongs to one of the basic and fundamental tasks in spatio-temporal data collection, analysis, and modeling. There are several approaches to this problem, which can be considered as a design or redesign of monitoring network by applying some optimization criteria. The most developed and widespread methods are based on geostatistics (family of kriging models, conditional stochastic simulations). In geostatistics the variance is mainly used as an optimization criterion which has some advantages and drawbacks. In the present research we study an application of advanced techniques following from the statistical learning theory (SLT) - support vector machines (SVM) and the optimization of monitoring networks when dealing with a classification problem (data are discrete values/classes: hydrogeological units, soil types, pollution decision levels, etc.) is considered. SVM is a universal nonlinear modeling tool for classification problems in high dimensional spaces. The SVM solution is maximizing the decision boundary between classes and has a good generalization property for noisy data. The sparse solution of SVM is based on support vectors - data which contribute to the solution with nonzero weights. Fundamentally the MNO for classification problems can be considered as a task of selecting new measurement points which increase the quality of spatial classification and reduce the testing error (error on new independent measurements). In SLT this is a typical problem of active learning - a selection of the new unlabelled points which efficiently reduce the testing error. A classical approach (margin sampling) to active learning is to sample the points closest to the classification boundary. This solution is suboptimal when points (or generally the dataset) are redundant for the same class. In the present research we propose and study two new advanced methods of active learning adapted to the solution of

  17. Advanced Nuclear Fuel Cycle Transitions: Optimization, Modeling Choices, and Disruptions

    Science.gov (United States)

    Carlsen, Robert W.

    Many nuclear fuel cycle simulators have evolved over time to help understan the nuclear industry/ecosystem at a macroscopic level. Cyclus is one of th first fuel cycle simulators to accommodate larger-scale analysis with it liberal open-source licensing and first-class Linux support. Cyclus also ha features that uniquely enable investigating the effects of modeling choices o fuel cycle simulators and scenarios. This work is divided into thre experiments focusing on optimization, effects of modeling choices, and fue cycle uncertainty. Effective optimization techniques are developed for automatically determinin desirable facility deployment schedules with Cyclus. A novel method fo mapping optimization variables to deployment schedules is developed. Thi allows relationships between reactor types and scenario constraints to b represented implicitly in the variable definitions enabling the usage o optimizers lacking constraint support. It also prevents wasting computationa resources evaluating infeasible deployment schedules. Deployed power capacit over time and deployment of non-reactor facilities are also included a optimization variables There are many fuel cycle simulators built with different combinations o modeling choices. Comparing results between them is often difficult. Cyclus flexibility allows comparing effects of many such modeling choices. Reacto refueling cycle synchronization and inter-facility competition among othe effects are compared in four cases each using combinations of fleet of individually modeled reactors with 1-month or 3-month time steps. There are noticeable differences in results for the different cases. The larges differences occur during periods of constrained reactor fuel availability This and similar work can help improve the quality of fuel cycle analysi generally There is significant uncertainty associated deploying new nuclear technologie such as time-frames for technology availability and the cost of buildin advanced reactors

  18. System for Road Vehicle Energy Optimization Using Real Time Road and Traffic Information

    OpenAIRE

    Felipe Jiménez; Wilmar Cabrera-Montiel

    2014-01-01

    Nowadays, reducing the energy and fuel consumption of road vehicles is a key issue. Different strategies have been proposed. One of them is to promote Eco-driving behaviour among drivers. Most Eco-driving tips take into account only the road stretch where the vehicle is located. However, larger improvements could be achieved if information from subsequent stretches is used. The main objective of this work is to develop a system to warn the driver in real time of the optimal speed that should ...

  19. Optimizing transport logistics taking into account the state of roads and road traffic

    Directory of Open Access Journals (Sweden)

    Shikul’skaya Ol’ga Mikhaylovna

    2015-12-01

    Full Text Available The choice and use of rational routes at strict observance of deliveries terms help to achieve not only minimization of operational expenses, but also to reduce commodity and production stocks in warehouses by 1,5...2 times. Therefore special relevance is gained by the works allowing precisely calculating the volumes of a cargo transportation, to count the quantity of transport units necessary for providing cargo flow, to define the rational routes of transportation, and also to reduce total costs of transportation. On the basis of the analysis of the known mathematical methods applied in transport logistics, the authors drew a conclusion that the route of freight delivery is estimated according to the distance passed by the vehicle. However the time of freight delivery depends not only on distance, but also on a set of other factors, such as vehicle type, road capacity, intensity of transport stream, weather conditions, season and others. For taking note of additional factors when optimizing a freight delivery route the method of analogy and similarity is used by the authors. The transportation parameters were estimated by analogy with an electric chain. For this purpose the authors entered the new concepts “fictitious distance” and “conductivity of the road”. The mathematical model allowing optimizing the organization of freight delivery taking into account not only distances, but also the probable speed of the vehicle movement depending on the road quality, intensity of transport stream and weather conditions is developed. Further development of the system of decision-making support while choosing the optimum route of cargo delivery is planned.

  20. APPLICATION OF SWARM INTELLIGENCE PSO TECHNIQUE FOR ANALYSIS OF MULTIMEDIA TRAFFIC AND QOS PARAMETERS USING OPTIMIZED LINK STATE ROUTING PROTOCOL

    Directory of Open Access Journals (Sweden)

    Dr. S. Meenakshi Sundaram

    2015-03-01

    Full Text Available Mobile ad hoc network (MANET nodes include wireless transmitters and receivers. At a given point in time, depending on the positions of the nodes, their transmitter and receiver coverage patterns, communication power levels and co-channel interference levels, a wireless connectivity in the form of a random, multi hop graph or “ad hoc" network exists among the nodes. In this research, it is proposed to modify OLSR using swarm intelligence, Particle Swarm Optimization (PSO, to reduce end to end delay and improve throughput in the network by traffic shaping at the network layer. The PSO algorithm represents each solution as a ‘bird’ in the search space and is referred to as ‘particle’. It uses the objective function to evaluate its candidate solutions, and operates on the resultant fitness values. Candidate solution and its estimated fitness, and velocity give the position of the particle. It also remembers the best fitness value it achieved till then during the algorithm’s operation which is usually referred to as the individual best fitness, and the candidate solution that achieved this fitness, is the individual best position ‘pbest’. The best fitness value attained among all particles in the swarm which is called global best fitness, and the candidate solution that attained this fitness, which is called the global best position or global best candidate solution ‘gbest’. OLSR generates link state information through nodes elected as Multi Point Relays (MPRs. It is proposed to modify OLSR using particle swarm optimization to reduce end to end delay and improve network throughput.

  1. Computational modeling, optimization and manufacturing simulation of advanced engineering materials

    CERN Document Server

    2016-01-01

    This volume presents recent research work focused in the development of adequate theoretical and numerical formulations to describe the behavior of advanced engineering materials.  Particular emphasis is devoted to applications in the fields of biological tissues, phase changing and porous materials, polymers and to micro/nano scale modeling. Sensitivity analysis, gradient and non-gradient based optimization procedures are involved in many of the chapters, aiming at the solution of constitutive inverse problems and parameter identification. All these relevant topics are exposed by experienced international and inter institutional research teams resulting in a high level compilation. The book is a valuable research reference for scientists, senior undergraduate and graduate students, as well as for engineers acting in the area of computational material modeling.

  2. Integration of Advanced Simulation and Visualization for Manufacturing Process Optimization

    Science.gov (United States)

    Zhou, Chenn; Wang, Jichao; Tang, Guangwu; Moreland, John; Fu, Dong; Wu, Bin

    2016-05-01

    The integration of simulation and visualization can provide a cost-effective tool for process optimization, design, scale-up and troubleshooting. The Center for Innovation through Visualization and Simulation (CIVS) at Purdue University Northwest has developed methodologies for such integration with applications in various manufacturing processes. The methodologies have proven to be useful for virtual design and virtual training to provide solutions addressing issues on energy, environment, productivity, safety, and quality in steel and other industries. In collaboration with its industrial partnerships, CIVS has provided solutions to companies, saving over US38 million. CIVS is currently working with the steel industry to establish an industry-led Steel Manufacturing Simulation and Visualization Consortium through the support of National Institute of Standards and Technology AMTech Planning Grant. The consortium focuses on supporting development and implementation of simulation and visualization technologies to advance steel manufacturing across the value chain.

  3. Real-Time Corrected Traffic Correlation Model for Traffic Flow Forecasting

    OpenAIRE

    Lu, Hua-pu; Sun, Zhi-yuan; Qu, Wen-cong; Wang, Ling

    2015-01-01

    This paper focuses on the problems of short-term traffic flow forecasting. The main goal is to put forward traffic correlation model and real-time correction algorithm for traffic flow forecasting. Traffic correlation model is established based on the temporal-spatial-historical correlation characteristic of traffic big data. In order to simplify the traffic correlation model, this paper presents correction coefficients optimization algorithm. Considering multistate characteristic of traffic ...

  4. Traffic Engineering in Metro Ethernet

    Directory of Open Access Journals (Sweden)

    Padmaraj Nair

    2010-05-01

    Full Text Available Traffic engineering is one of the major issues that has to be addressed in Metro Ethernet networks for quality of service and efficient resource utilization. This paper aims at understanding the relevant issues and outlines novel algorithms for multipoint traffic engineering in Metro Ethernet. We present an algorithmic solution for traffic engineering in Metro Ethernet using optimal multiple spanning trees. This iterative approach distributes traffic across the network uniformly without overloading network resources. We also introduce a new traffic specification model for Metro Ethernet, which is a hybrid of two widely used traffic specification models, the pipe and hose models.

  5. Traffic Engineering in Metro Ethernet

    OpenAIRE

    Padmaraj Nair; Suku Nair; Girish Chiruvolu

    2010-01-01

    Traffic engineering is one of the major issues that has to be addressed in Metro Ethernet networks for quality of service and efficient resource utilization. This paper aims at understanding the relevant issues and outlines novel algorithms for multipoint traffic engineering in Metro Ethernet. We present an algorithmic solution for traffic engineering in Metro Ethernet using optimal multiple spanning trees. This iterative approach distributes traffic across the network uniformly without overl...

  6. Traffic congestion forecasting model for the INFORM System. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Azarm, A.; Mughabghab, S.; Stock, D.

    1995-05-01

    This report describes a computerized traffic forecasting model, developed by Brookhaven National Laboratory (BNL) for a portion of the Long Island INFORM Traffic Corridor. The model has gone through a testing phase, and currently is able to make accurate traffic predictions up to one hour forward in time. The model will eventually take on-line traffic data from the INFORM system roadway sensors and make projections as to future traffic patterns, thus allowing operators at the New York State Department of Transportation (D.O.T.) INFORM Traffic Management Center to more optimally manage traffic. It can also form the basis of a travel information system. The BNL computer model developed for this project is called ATOP for Advanced Traffic Occupancy Prediction. The various modules of the ATOP computer code are currently written in Fortran and run on PC computers (pentium machine) faster than real time for the section of the INFORM corridor under study. The following summarizes the various routines currently contained in the ATOP code: Statistical forecasting of traffic flow and occupancy using historical data for similar days and time (long term knowledge), and the recent information from the past hour (short term knowledge). Estimation of the empirical relationships between traffic flow and occupancy using long and short term information. Mechanistic interpolation using macroscopic traffic models and based on the traffic flow and occupancy forecasted (item-1), and the empirical relationships (item-2) for the specific highway configuration at the time of simulation (construction, lane closure, etc.). Statistical routine for detection and classification of anomalies and their impact on the highway capacity which are fed back to previous items.

  7. Advances in metaheuristic algorithms for optimal design of structures

    CERN Document Server

    Kaveh, A

    2014-01-01

    This book presents efficient metaheuristic algorithms for optimal design of structures. Many of these algorithms are developed by the author and his colleagues, consisting of Democratic Particle Swarm Optimization, Charged System Search, Magnetic Charged System Search, Field of Forces Optimization, Dolphin Echolocation Optimization, Colliding Bodies Optimization, Ray Optimization. These are presented together with algorithms which were developed by other authors and have been successfully applied to various optimization problems. These consist of Particle Swarm Optimization, Big Bang-Big Crunch Algorithm, Cuckoo Search Optimization, Imperialist Competitive Algorithm, and Chaos Embedded Metaheuristic Algorithms. Finally a multi-objective optimization method is presented to solve large-scale structural problems based on the Charged System Search algorithm. The concepts and algorithms presented in this book are not only applicable to optimization of skeletal structures and finite element models, but can equally ...

  8. Robust and reactive traffic engineering for dynamic traffic demands

    OpenAIRE

    Casas Hernandez, Pedro; Fillatre, Lionel; Vaton, Sandrine

    2008-01-01

    Traffic engineering (TE) has become a challenging mechanism for network management and resources optimization due to uncertain and difficult to predict traffic patterns. Recent works have proposed robust optimization techniques to cope with uncertain traffic, computing a stable routing configuration that is immune to demand variations within certain uncertainty set. However, using a single routing configuration for longtime periods can be highly inefficient. Even more, the presence of abnorma...

  9. Advanced Variance Reduction Strategies for Optimizing Mesh Tallies in MAVRIC

    International Nuclear Information System (INIS)

    More often than in the past, Monte Carlo methods are being used to compute fluxes or doses over large areas using mesh tallies (a set of region tallies defined on a mesh that overlays the geometry). For problems that demand that the uncertainty in each mesh cell be less than some set maximum, computation time is controlled by the cell with the largest uncertainty. This issue becomes quite troublesome in deep-penetration problems, and advanced variance reduction techniques are required to obtain reasonable uncertainties over large areas. The CADIS (Consistent Adjoint Driven Importance Sampling) methodology has been shown to very efficiently optimize the calculation of a response (flux or dose) for a single point or a small region using weight windows and a biased source based on the adjoint of that response. This has been incorporated into codes such as ADVANTG (based on MCNP) and the new sequence MAVRIC, which will be available in the next release of SCALE. In an effort to compute lower uncertainties everywhere in the problem, Larsen's group has also developed several methods to help distribute particles more evenly, based on forward estimates of flux. This paper focuses on the use of a forward estimate to weight the placement of the source in the adjoint calculation used by CADIS, which we refer to as a forward-weighted CADIS (FW-CADIS)

  10. MPC in Urban Traffic Management

    OpenAIRE

    Tettamanti, Tamás; Varga, Istvan; Peni, Tamas

    2010-01-01

    This chapter introduced the aspects of MPC applied in urban traffic management. As the urban traffic is a complex system having special attributes the appropriate traffic model had to be discussed in details as well. At the same time MPC technology is suitable to control such complex system optimally and real-time. The main control aim was the optimal and coordinated control which can be satisfied. The applicability was demonstrated by several simulations. Furthermore a distributed technology...

  11. Network Traffic Prediction Based on Neural Network Optimized by ACO%蚁群算法优化RBF神经网络的网络流量预测

    Institute of Scientific and Technical Information of China (English)

    廖金权

    2012-01-01

    Traditional RBF neural network in the forecasting process of the network traffic convergence is slow, prone to local optima and other shortcomings, resulting in low prediction accuracy and difficult problems. In order to improve the prediction accuracy of network traffic, network traffic prediction method for an ant colony algorithm to optimize the parameters of RBF neural network. Ant colony algorithm for training RBF neural network center and the width of the basis functions to speed up the convergence, simplifying the network structure to improve the generalization capability of RBF neural networks, and optimized RBF neural network to predict the network traffic, to prevent local optimum to appear. The experimental results show that relative to the commonly used BP neural network traffic prediction model, model predictions more accurate, can be well described by the variation of the network flow. With good generalization ability, good stability and a certain practical value in the prediction of network traffic.%传统RBF神经网络在网络流量预测过程中存在收敛速度慢、极易出现局部最优等缺点,从而导致预测精度低.采用蚁群算法优化RBF神经网络参数来进行网络流量预测.利用蚁群优化算法来训练RBF神经网络的基函数宽度和中心,简化网络结构,加快收敛速度,防止局部最优的出现,改善RBF神经网络的泛化能力.实验结果表明,相对于GA-RBF以及PSO-RBF流量预测模型,模型预测准确度更高,能够很好地描述网络流的变化规律.具有泛化能力强、稳定性良好的特点,在网络流量预测中有一定的实用价值.

  12. A SPATIOTEMPORAL APPROACH FOR HIGH RESOLUTION TRAFFIC FLOW IMPUTATION

    Energy Technology Data Exchange (ETDEWEB)

    Han, Lee [University of Tennessee, Knoxville (UTK); Chin, Shih-Miao [ORNL; Hwang, Ho-Ling [ORNL

    2016-01-01

    Along with the rapid development of Intelligent Transportation Systems (ITS), traffic data collection technologies have been evolving dramatically. The emergence of innovative data collection technologies such as Remote Traffic Microwave Sensor (RTMS), Bluetooth sensor, GPS-based Floating Car method, automated license plate recognition (ALPR) (1), etc., creates an explosion of traffic data, which brings transportation engineering into the new era of Big Data. However, despite the advance of technologies, the missing data issue is still inevitable and has posed great challenges for research such as traffic forecasting, real-time incident detection and management, dynamic route guidance, and massive evacuation optimization, because the degree of success of these endeavors depends on the timely availability of relatively complete and reasonably accurate traffic data. A thorough literature review suggests most current imputation models, if not all, focus largely on the temporal nature of the traffic data and fail to consider the fact that traffic stream characteristics at a certain location are closely related to those at neighboring locations and utilize these correlations for data imputation. To this end, this paper presents a Kriging based spatiotemporal data imputation approach that is able to fully utilize the spatiotemporal information underlying in traffic data. Imputation performance of the proposed approach was tested using simulated scenarios and achieved stable imputation accuracy. Moreover, the proposed Kriging imputation model is more flexible compared to current models.

  13. A new intelligent method of optimal route choice of public traffic network%一种公交换乘路线智能选择的新方法

    Institute of Scientific and Technical Information of China (English)

    陈丽佳; 邹峥嵘; 李光强

    2009-01-01

    Public traffic transfer is an important problem to public traffic querying. The paper firstly describes the classical Dijkstra algorithm, and analyzes the reason that it is not fit to optimum route selection of public transportation network. Then the paper presents an advanced Dijkstra algorithm, this algorithm takes the stations which are the solution of the shortest path problem as the searched stations, and makes up of the transfer matrix with those stations and the traffic lines passing by, according to the request of the transfer time, the paper puts forward a transfer arithmetic based on Dijkstra algorithm. Finally, the paper proves the feasibility of the improved Dijkstra algorithm applying to Optimal Route Choice by an example.%公交换乘问题是公共交通信息查询的重要内容,本文首先叙述了经典Dijkstra算法,并分析了其不适合公交网络最优路径选择的原因.然后提出了一种改进的 Dijkstra 算法,该算法将求解最短路径获得的站点作为搜索站点,并将这些站点及经过这些站点的线路构成换乘矩阵,结合换乘次数的要求,给出了基于Dijkstra的智能选择换乘线路的实现算法.最后通过一个实际算例说明改进的Dijkstra算法在公交换乘路线选择中应用的可行性.

  14. Advanced Air Traffic Management Research (Human Factors and Automation): NASA Research Initiatives in Human-Centered Automation Design in Airspace Management

    Science.gov (United States)

    Corker, Kevin M.; Condon, Gregory W. (Technical Monitor)

    1996-01-01

    NASA has initiated a significant thrust of research and development focused on providing the flight crew and air traffic managers automation aids to increase capacity in en route and terminal area operations through the use of flexible, more fuel-efficient routing, while improving the level of safety in commercial carrier operations. In that system development, definition of cognitive requirements for integrated multi-operator dynamic aiding systems is fundamental. The core processes of control and the distribution of decision making in that control are undergoing extensive analysis. From our perspective, the human operators and the procedures by which they interact are the fundamental determinants of the safe, efficient, and flexible operation of the system. In that perspective, we have begun to explore what our experience has taught will be the most challenging aspects of designing and integrating human-centered automation in the advanced system. We have performed a full mission simulation looking at the role shift to self-separation on board the aircraft with the rules of the air guiding behavior and the provision of a cockpit display of traffic information and an on-board traffic alert system that seamlessly integrates into the TCAS operations. We have performed and initial investigation of the operational impact of "Dynamic Density" metrics on controller relinquishing and reestablishing full separation authority. (We follow the assumption that responsibility at all times resides with the controller.) This presentation will describe those efforts as well as describe the process by which we will guide the development of error tolerant systems that are sensitive to shifts in operator work load levels and dynamic shifts in the operating point of air traffic management.

  15. Study on the Traffic Congestion in Beijing

    OpenAIRE

    Ma Xiaofei

    2013-01-01

    As the the rapid growth of city economy, a traffic congestion has become a common sight in almost every big city. On the surface, the infrastructure construction is incompatible with the rapid expansion of the city cars. In fact,the root cause lies in the careless and easy style of management of traffic which leads to the low traffic efficiency. This study mainly describes the traffic system, the causes of traffic congestion, discussing on the optimization to ...

  16. Data reduction in modeled packet traffic

    OpenAIRE

    Mehrabian, Maryam

    2012-01-01

        Within Ericsson there is a continuous activity of traffic modeling. Traffic modeling is a practice to analyze traffic patterns and determine necessary resources to handle it optimally. This activity focuses on gathering and analyzing live network measurements, implementing and presenting traffic models. One example of concept in packet traffic modeling is transmission object log which is an aggregation of packet data traces from a measured network over a transmission period. These trace l...

  17. Heavy traffic analysis of open processing networks with complete resource pooling: asymptotic optimality of discrete review policies

    OpenAIRE

    Ata, Baris; Sunil KUMAR

    2005-01-01

    We consider a class of open stochastic processing networks, with feedback routing and overlapping server capabilities, in heavy traffic. The networks we consider satisfy the so-called complete resource pooling condition and therefore have one-dimensional approximating Brownian control problems. We propose a simple discrete review policy for controlling such networks. Assuming 2+\\epsilon moments on the interarrival times and processing times, we provide a conceptually simple proof of asymptoti...

  18. Traffic Light Control by Multiagent Reinforcement Learning Systems

    NARCIS (Netherlands)

    Bakker, B.; Whiteson, S.; Kester, L.J.H.M.; Groen, F.C.A.

    2010-01-01

    Traffic light control is one of the main means of controlling road traffic. Improving traffic control is important because it can lead to higher traffic throughput and reduced traffic congestion. This chapter describes multiagent reinforcement learning techniques for automatic optimization of traffi

  19. Traffic light control by multiagent reinforcement learning systems

    NARCIS (Netherlands)

    B. Bakker; S. Whiteson; L. Kester; F.C.A. Groen

    2010-01-01

    Traffic light control is one of the main means of controlling road traffic. Improving traffic control is important because it can lead to higher traffic throughput and reduced traffic congestion. This chapter describes multiagent reinforcement learning techniques for automatic optimization of traffi

  20. Advancing interconnect density for spiking neural network hardware implementations using traffic-aware adaptive network-on-chip routers.

    Science.gov (United States)

    Carrillo, Snaider; Harkin, Jim; McDaid, Liam; Pande, Sandeep; Cawley, Seamus; McGinley, Brian; Morgan, Fearghal

    2012-09-01

    The brain is highly efficient in how it processes information and tolerates faults. Arguably, the basic processing units are neurons and synapses that are interconnected in a complex pattern. Computer scientists and engineers aim to harness this efficiency and build artificial neural systems that can emulate the key information processing principles of the brain. However, existing approaches cannot provide the dense interconnect for the billions of neurons and synapses that are required. Recently a reconfigurable and biologically inspired paradigm based on network-on-chip (NoC) and spiking neural networks (SNNs) has been proposed as a new method of realising an efficient, robust computing platform. However, the use of the NoC as an interconnection fabric for large-scale SNNs demands a good trade-off between scalability, throughput, neuron/synapse ratio and power consumption. This paper presents a novel traffic-aware, adaptive NoC router, which forms part of a proposed embedded mixed-signal SNN architecture called EMBRACE (EMulating Biologically-inspiRed ArChitectures in hardwarE). The proposed adaptive NoC router provides the inter-neuron connectivity for EMBRACE, maintaining router communication and avoiding dropped router packets by adapting to router traffic congestion. Results are presented on throughput, power and area performance analysis of the adaptive router using a 90 nm CMOS technology which outperforms existing NoCs in this domain. The adaptive behaviour of the router is also verified on a Stratix II FPGA implementation of a 4 × 2 router array with real-time traffic congestion. The presented results demonstrate the feasibility of using the proposed adaptive NoC router within the EMBRACE architecture to realise large-scale SNNs on embedded hardware. PMID:22561008

  1. Complexity in Air Traffic Management

    OpenAIRE

    Delahaye, Daniel; Puechmorel, Stéphane; Dougui, Nour Elhouda

    2009-01-01

    Air traffic Management Requirements : -Insure separation between aircraft. -Avoid costly manoeuvres and optionally optimize trajectories. -Insure trafic organization. Trends : -Separation delegated to aircraft. -Trajectory based air traffic management. -Introduction of decision support tools / automated conflict solvers. Workload : -Related to cognitive processes of human controllers. -Easy/Hard forecasting of conflict occurrence. -Monitoring is a non negligible part of the workload. -Relevan...

  2. Aeroelastic optimization of an advanced geometry helicopter rotor

    Science.gov (United States)

    Ganguli, Ranjan; Chopra, Inderjit

    1992-01-01

    Sensitivity derivatives of blade loads and aeroelastic stability of a helicopter rotor in forward flight are calculated as an integral part of a basic aeroelastic analysis using a direct analytical approach. Design variables include nonstructural mass and its placement, chordwise offset of blade center of gravity and aerodynamic center from the elastic axis, blade bending stiffnesses (flap, lag, torsion), and tip geometry (sweep, anhedral, pretwist and planform taper). By means of a sensitivity study, the importance of different design variables on oscillatory hub loads and damping of blade modes is examined. Aeroelastic and sensitivity analyses of the rotor based on a finite element method in space and time are linked with automated optimization algorithms to perform optimization studies of rotor blades. Optimum design solutions, calculated for a four-bladed, soft-inplane hingeless rotor achieved a reduction of 25-60 percent of all 4/rev loads.

  3. Dynamic Modeling, Optimization, and Advanced Control for Large Scale Biorefineries

    DEFF Research Database (Denmark)

    Prunescu, Remus Mihail

    balances with a complex conversion route. Computational fluid dynamics is used to model transport phenomena in large reactors capturing tank profiles, and delays due to plug flows. This work publishes for the first time demonstration scale real data for validation showing that the model library is suitable...... study deals with building a plantwide model-based optimization layer, which searches for optimal values regarding the pretreatment temperature, enzyme dosage in liquefaction, and yeast seed in fermentation such that profit is maximized [7]. When biomass is pretreated, by-products are also created that...... bottlenecks and which feedstock components need to be determined for an accurate prediction. This analysis is achieved with Monte Carlo simulations and Latin Hypercube Sampling (LHS) on feedstock composition and kinetic parameters following the methodology from [5, 6, 8, 9]. In the last part of this work, two...

  4. Advanced optimization of permanent magnet wigglers using a genetic algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Hajima, Ryoichi [Univ. of Tokyo (Japan)

    1995-12-31

    In permanent magnet wigglers, magnetic imperfection of each magnet piece causes field error. This field error can be reduced or compensated by sorting magnet pieces in proper order. We showed a genetic algorithm has good property for this sorting scheme. In this paper, this optimization scheme is applied to the case of permanent magnets which have errors in the direction of field. The result shows the genetic algorithm is superior to other algorithms.

  5. Data Fusion and Evolutionary Query Optimization for Advanced Search

    Czech Academy of Sciences Publication Activity Database

    Húsek, Dušan; Keyhanipour, A.; Krömer, P.; Moshiri, B.; Owais, S.; Snášel, V.

    Ostrava : VŠB Technická univerzita, 2007 - (Snášel, V.; Platoš, J.), s. 82-92 ISBN 978-80-248-1332-5. [WETDAP 2007. Workshop in Conjunction with Znalosti 2007 /1./. Ostrava (CZ), 22.02.2007-22.02.2007] Institutional research plan: CEZ:AV0Z10300504 Keywords : Web search * meta-search * user modeling * evolutionary algorithms * query optimization Subject RIV: BB - Applied Statistics, Operational Research

  6. 城市道路通行能力影响模型优化及其推广%Optimization and its Extension on the Impact Model of Urban Road' s Traffic Capacity at Lane Occupied

    Institute of Scientific and Technical Information of China (English)

    倪仁兴; 沈婷; 胡静雅; 陈靖倩

    2015-01-01

    利用交通流理论等知识,借助于SPSS和MATLAB软件,考察实际交通堵塞道路的通行能力,通过对真实事故现场数据的采集分析,受经典的logistic人口模型启发,提出并建立了阻滞增长模型,得到了拥堵时车辆排队长度与持续时间、通行能力、车流量之间的关系.建立了城市道路被占时的车辆排队长度和其影响因子探究的数学模型,给出了上游路口信号灯配时方案和交通组织方案.运用阻滞增长模型可有效优化城市道路通行能力,缓解城市交通压力,改善交通环境.%In china, traffic congestion has become a serious problem in today's increasingly prominent on growing probloms of urban traffic. But, many older urban road planning form earlier, the existing urban road construction is so far as behind the economic development at present,. Among them, the lane occupied has become the big-gest problem of the traffic congestion, including traffic problem, street parking, lane construction and so on. This paper aims to take advantage of the knowledge of traffic flow theory, by SPSS and MATLAB software, the actual traffic jam road traffic capacity is examined, using the real scene of the accident, as reflected in the video data acquisition and analysis, inspired by the classic logistic population model, a block growth model is proposed and established. The relationship about vehicle queue length, time duration, traffic capacity and traffic flow is obtained. Meanwhile, according to the people's traffic expectations, we established model about vehicle queue length and its influencing factors in response to urban road occupied, and given timing program and traffic organ-ization scheme of upstream crossing signal lights. The use of block growth model can effectively optimize urban road capacity, ease urban traffic pressure and improve the traffic environment.

  7. Optimization of wind turbine rotors - using advanced aerodynamic and aeroelastic models and numerical optimization

    DEFF Research Database (Denmark)

    Døssing, Mads

    of very large machines introduces new problems in the practical design, and optimization tools are necessary. These must combine the dynamic eects of both aerodynamics and structure in an integrated optimization environment. This is referred to as aeroelastic optimization. The Ris DTU optimization......During the last decades the annual energy produced by wind turbines has increased dramatically and wind turbines are now available in the 5MW range. Turbines in this range are constantly being developed and it is also being investigated whether turbines as large as 10-20MW are feasible. The design...

  8. Network traffic prediction method based on KPCA optimized ESN%基于KPCA优化ESN的网络流量预测方法

    Institute of Scientific and Technical Information of China (English)

    田中大; 李树江; 王艳红; 高宪文

    2015-01-01

    为了提高网络流量的预测精确度,提出一种核主成分分析( KPCA )优化回声状态网络( ESN)的网络流量预测方法. 首先利用相空间重构对网络流量序列进行处理,提高序列的可预测性,然后对网络流量序列进行核主成分分析,提取序列中的有效信息,通过实验方法确定回声状态网络的储备池参数,最后利用回声状态网络对网络流量进行预测. 与标准回声状态网络、差分自回归滑动平均模型( ARIMA)、以及最小二乘支持向量机( LSSVM)预测模型进行了仿真对比,结果表明提出的方法具有更高的预测精确度以及更小的预测误差,同时一定程度上减少了预测时间.%In order to improve the prediction accuracy of network traffic, a network traffic prediction method based on kernel principal component analysis ( KPCA) optimized echo state network ( ESN) was proposed. Firstly, network traffic series was processed to improve the predictability by phase space recon-struction, then the effective information was extracted through kernel principal component analysis. The reservoir parameters of echo state network were determined through the experiment method. Finally, net-work traffic was predicted through the echo state network. The proposed method is compared with stand-ard echo state netowrk, auto regressive integrated moving average ( ARIMA) , and least squares support vector machine ( LSSVM) predictive model. The simulation results show that the proposed method has higher prediction accuracy with smaller predictive error, at the same time the prediction time is reduced.

  9. Advances in Optimizing Weather Driven Electric Power Systems.

    Science.gov (United States)

    Clack, C.; MacDonald, A. E.; Alexander, A.; Dunbar, A. D.; Xie, Y.; Wilczak, J. M.

    2014-12-01

    The importance of weather-driven renewable energies for the United States (and global) energy portfolio is growing. The main perceived problems with weather-driven renewable energies are their intermittent nature, low power density, and high costs. The National Energy with Weather System Simulator (NEWS) is a mathematical optimization tool that allows the construction of weather-driven energy sources that will work in harmony with the needs of the system. For example, it will match the electric load, reduce variability, decrease costs, and abate carbon emissions. One important test run included existing US carbon-free power sources, natural gas power when needed, and a High Voltage Direct Current power transmission network. This study shows that the costs and carbon emissions from an optimally designed national system decrease with geographic size. It shows that with achievable estimates of wind and solar generation costs, that the US could decrease its carbon emissions by up to 80% by the early 2030s, without an increase in electric costs. The key requirement would be a 48 state network of HVDC transmission, creating a national market for electricity not possible in the current AC grid. These results were found without the need for storage. Further, we tested the effect of changing natural gas fuel prices on the optimal configuration of the national electric power system. Another test that was carried out was an extension to global regions. The extension study shows that the same properties found in the US study extend to the most populous regions of the planet. The extra test is a simplified version of the US study, and is where much more research can be carried out. We compare our results to other model results.

  10. Advanced hybrid and electric vehicles system optimization and vehicle integration

    CERN Document Server

    2016-01-01

    This contributed volume contains the results of the research program “Agreement for Hybrid and Electric Vehicles”, funded by the International Energy Agency. The topical focus lies on technology options for the system optimization of hybrid and electric vehicle components and drive train configurations which enhance the energy efficiency of the vehicle. The approach to the topic is genuinely interdisciplinary, covering insights from fields. The target audience primarily comprises researchers and industry experts in the field of automotive engineering, but the book may also be beneficial for graduate students.

  11. Electric power systems advanced forecasting techniques and optimal generation scheduling

    CERN Document Server

    Catalão, João P S

    2012-01-01

    Overview of Electric Power Generation SystemsCláudio MonteiroUncertainty and Risk in Generation SchedulingRabih A. JabrShort-Term Load ForecastingAlexandre P. Alves da Silva and Vitor H. FerreiraShort-Term Electricity Price ForecastingNima AmjadyShort-Term Wind Power ForecastingGregor Giebel and Michael DenhardPrice-Based Scheduling for GencosGovinda B. Shrestha and Songbo QiaoOptimal Self-Schedule of a Hydro Producer under UncertaintyF. Javier Díaz and Javie

  12. Multi-objective optimization of combined Brayton and inverse Brayton cycles using advanced optimization algorithms

    Science.gov (United States)

    Venkata Rao, R.; Patel, Vivek

    2012-08-01

    This study explores the use of teaching-learning-based optimization (TLBO) and artificial bee colony (ABC) algorithms for determining the optimum operating conditions of combined Brayton and inverse Brayton cycles. Maximization of thermal efficiency and specific work of the system are considered as the objective functions and are treated simultaneously for multi-objective optimization. Upper cycle pressure ratio and bottom cycle expansion pressure of the system are considered as design variables for the multi-objective optimization. An application example is presented to demonstrate the effectiveness and accuracy of the proposed algorithms. The results of optimization using the proposed algorithms are validated by comparing with those obtained by using the genetic algorithm (GA) and particle swarm optimization (PSO) on the same example. Improvement in the results is obtained by the proposed algorithms. The results of effect of variation of the algorithm parameters on the convergence and fitness values of the objective functions are reported.

  13. Advanced VIRGO: detector optimization for gravitational waves by inspiralling binaries

    CERN Document Server

    Spallicci, A D; De Pacheco, J F; Frossati, G; Regimbau, T; Spallicci, Alessandro D.A.M.; Aoudia, Sofiane; Pacheco, Jose De Freitas; Frossati, Giorgio; Regimbau, Tania

    2004-01-01

    Among sources, coalescing binaries appear among the most interesting and known. Thus, improvements in signal to noise ratio (S/N) by noise abatement in VIRGO, for inspiralling binaries of small chirp mass, are discussed. VIRGO detection bandwidth is divided into four sub-bands according to the dominant noise (whether seismic, thermal from pendula and mirrors, shot). Firstly, it is identified that mirror thermal noise reduction provides the highest gain increment in S/N. On the assumption that the technological challenges lying ahead, and the relative necessary budgets, are equally relevant in all sub-bands, it is recommended to gear R&D strategies to a future EURO detector operating at cryogenic temperatures. Secondly, the frequency of 50 Hz is identified as the single optimal frequency at which lies the potential largest increment in S/N for VIRGO. Thirdly, enlargement of the bandwidth, where noise is reduced, produces a shift to higher frequency of the optimal frequency (e.g. for 100 Hz band, the optima...

  14. Advanced metaheuristic algorithms for laser optimization in optical accelerator technologies

    Science.gov (United States)

    Tomizawa, Hiromitsu

    2011-10-01

    Lasers are among the most important experimental tools for user facilities, including synchrotron radiation and free electron lasers (FEL). In the synchrotron radiation field, lasers are widely used for experiments with Pump-Probe techniques. Especially for X-ray-FELs, lasers play important roles as seed light sources or photocathode-illuminating light sources to generate a high-brightness electron bunch. For future accelerators, laser-based techonologies such as electro-optic (EO) sampling to measure ultra-short electron bunches and optical-fiber-based femtosecond timing systems have been intensively developed in the last decade. Therefore, controls and optimizations of laser pulse characteristics are strongly required for many kinds of experiments and improvement of accelerator systems. However, people believe that lasers should be tuned and customized for each requirement manually by experts. This makes it difficult for laser systems to be part of the common accelerator infrastructure. Automatic laser tuning requires sophisticated algorithms, and the metaheuristic algorithm is one of the best solutions. The metaheuristic laser tuning system is expected to reduce the human effort and time required for laser preparations. I have shown some successful results on a metaheuristic algorithm based on a genetic algorithm to optimize spatial (transverse) laser profiles, and a hill-climbing method extended with a fuzzy set theory to choose one of the best laser alignments automatically for each machine requirement.

  15. Traffic organization optimization on widening road for preventing structure damage%预防结构破坏的拼接路面交通组织优化

    Institute of Scientific and Technical Information of China (English)

    刘东泽; 韩丁; 朱俊骅; 肖益民

    2014-01-01

    To prevent secondary damage of widening road structure in construction process ,the traffic organiza-tion optimization was implemented .The original road surface cracking and subgrade plastic deformation were simulated on the position of construction joint .The conditions and diseases in road widening of Hefei-Nanjing Expressway were analyzed .According to the values of tensile stress and plastic strain ,optimal traffic organi-zation was achieved by adjusting the values of vehicle loads ,tire edge distance away from road excavation sec-tion and the height between original pavement surface and subgrade widening excavation .The vehicle load and the distance between vehicle load position and excavation section are two important factors which determine whether the surface cracking and subgrade collapse will occur .The original subgrade excavation depth can be flexibly controlled .A reasonable traffic organization mode on widening road can be quickly determined by the comprehensive critical condition graph of two kinds of diseases .%为防止路面拼接结构在施工过程中的二次破坏,文章基于接缝位置原路表面拉裂和路基塑性变形的数值仿真进行交通组织优化;分析了合宁高速公路路面拼接中的工况和病害,通过分别调整车辆荷载的大小、轮胎边缘距开挖断面距离和原有路面结构开挖时距拼接路基高差,依据拉应力和塑性应变指标确定合理的交通组织方式。车辆轴载和荷载距开挖断面距离是确定原有沥青面层表面是否会出现拉裂及道路路基开挖后是否会出现崩塌的重要条件,原有路基的开挖深度可以机动控制。根据2种病害综合临界条件曲线图能够快速确定合理的拼接路面交通组织方式。

  16. Embedded System For Intelligent Ambulance And Traffic Control Management

    OpenAIRE

    Sarika Baburao Kale; Gajanan P. Dhok

    2013-01-01

    The use of Embedded technology has proved to be very beneficial in  present Traffic Light Controller (TLC) and that will minimize waiting time of vehicle and also manage traffic load. In this paper we exploit the emergence of new technology called as Intelligent traffic light controller, This makes the use of sensor n/w along with embedded technology. Where traffic light will be intelligently decided based on the total traffic on all adjacent roads. Thus optimization of traffic light switchin...

  17. Optimization of wind turbine rotors - using advanced aerodynamic and aeroelastic models and numerical optimization

    Energy Technology Data Exchange (ETDEWEB)

    Doessing, M.

    2011-05-15

    During the last decades the annual energy produced by wind turbines has increased dramatically and wind turbines are now available in the 5MW range. Turbines in this range are constantly being developed and it is also being investigated whether turbines as large as 10-20MW are feasible. The design of very large machines introduces new problems in the practical design, and optimization tools are necessary. These must combine the dynamic effects of both aerodynamics and structure in an integrated optimization environment. This is referred to as aeroelastic optimization. The Risoe DTU optimization software HAWTOPT has been used in this project. The quasi-steady aerodynamic module have been improved with a corrected blade element momentum method. A structure module has also been developed which lays out the blade structural properties. This is done in a simplified way allowing fast conceptual design studies and with focus on the overall properties relevant for the aeroelastic properties. Aeroelastic simulations in the time domain were carried out using the aeroelastic code HAWC2. With these modules coupled to HAWTOPT, optimizations have been made. In parallel with the developments of the mentioned numerical modules, focus has been on analysis and a fundamental understanding of the key parameters in wind turbine design. This has resulted in insight and an effective design methodology is presented. Using the optimization environment a 5MW wind turbine rotor has been optimized for reduced fatigue loads due to apwise bending moments. Among other things this has indicated that airfoils for wind turbine blades should have a high lift coefficient. The design methodology proved to be stable and a help in the otherwise challenging task of numerical aeroelastic optimization. (Author)

  18. Multiagent Reinforcement Learning for Urban Traffic Control Using Coordination Graphs

    OpenAIRE

    Kuyer, Lior; Whiteson, Shimon; Bakker, Bram; Vlassis, Nikos

    2008-01-01

    Since traffic jams are ubiquitous in the modern world, optimizing, the behavior of traffic lights for efficient traffic flow is a critically important goal. Though most current traffic lights use simple heuristic protocols, more efficient controllers can be discovered automatically via multiagent reinforcement learning where each agent controls a single traffic light. However, in previous work on this approach, agents select only locally optimal actions without coordinating their behavior. Th...

  19. Advanced Neutron Source Reactor zoning, shielding, and radiological optimization guide

    International Nuclear Information System (INIS)

    In the design of major nuclear facilities, it is important to protect both humans and equipment excessive radiation dose. Past experience has shown that it is very effective to apply dose reduction principles early in the design of a nuclear facility both to specific design features and to the manner of operation of the facility, where they can aid in making the facility more efficient and cost-effective. Since the appropriate choice of radiological controls and practices varies according to the case, each area of the facility must be analyzed for its radiological impact, both by itself and in interactions with other areas. For the Advanced Neutron Source (ANS) project, a large relational database will be used to collect facility information by system and relate it to areas. The database will also hold the facility dose and shielding information as it is produced during the design process. This report details how the ANS zoning scheme was established and how the calculation of doses and shielding are to be done

  20. Optimization of advanced plants operation: The Escrime project

    International Nuclear Information System (INIS)

    The Escrime program aims at defining the optimal share of tasks between humans and computers under normal or accidental plant operation. Basic principles we keep in mind are the following: human operators are likely to be necessary in the operation of future plants because we cannot demonstrate that plant design is error free, so unexpected situation can still happen; automation must not release the operators from their decisional role but only help them avoiding situations of cognitive overload which can lead to increase the risk of errors; the optimum share of tasks between human and automatic systems must be based on a critical analysis of the tasks and of the way they are handled. The last point appeared to be of major importance. The corresponding analysis of the French PWR's operating procedures enabled us to define a unified scheme for plant operation under the form of a hierarchy of goals and means. Beyond this analysis, development of a specific testing facility is under way to check the relevance of the proposed plant operation organization and to test the human-machine cooperation in different situations for various levels of automation. 7 refs, 4 figs

  1. Reduction of anthropogenic environmental influences by advanced and optimized technologies / Pollmann O.A.

    OpenAIRE

    Pollmann, Olaf Axel.

    2012-01-01

    Sustainable development and resource efficiency are the common global strategies of the 21st century. The actual global natural resource consumption of humankind went far over the limit and to cover this worldwide resource consumption the productivity of 1.5 earths is now necessary. The work “Reduction of anthropogenic environmental influences by advanced and optimized technologies” discussed the problem of advanced resource efficiencies with mining activities in South Afric...

  2. Data Mining using Advanced Ant Colony Optimization Algorithm and Application to Bankruptcy Prediction

    OpenAIRE

    Vishal Arora; Vadlamani Ravi

    2013-01-01

    Ant Colony Optimization (ACO) is gaining popularity as data mining technique in the domain of Swarm Intelligence for its simple, accurate and comprehensive nature of classification. In this paper the authors propose a novel advanced version of the original ant colony based miner (Ant-Miner) in order to extract classification rules from data. They call this Advanced ACO-Miner (ADACOM). The main goal of ADACOM is to explore the flexibility of using a different knowledge extraction heuristic app...

  3. Optimal synthesis and operation of advanced energy supply systems for standard and domotic home

    International Nuclear Information System (INIS)

    Highlights: ► Definition of an optimization model for a home energy supply system. ► Optimization of the energy supply system for standard and domotic home. ► Strong improvement can be achieved adopting the optimal system in standard and domotic home. ► The improvements are consistent if supply side and demand side strategies are applied together. ► Solutions with internal combustion engines are less sensible to market price of electricity and gas. - Abstract: The paper deals with the optimization of an advanced energy supply systems for two dwellings: a standard home and an advanced domotic home, where some demand side energy saving strategies have been implemented. In both cases the optimal synthesis, design and operation of the whole energy supply system have been obtained and a sensitivity analysis has been performed, by introducing different economic constraints. The optimization model is based on a Mixed Integer Linear Program (MILP) and includes different kinds of small-scale cogenerators, geothermal heat pumps, boilers, heat storages, solar thermal and photovoltaic panels. In addition, absorption machines, supplied with cogenerated heat, can be used instead of conventional electrical chiller to face the cooling demand. The aim of the analysis is to address the question if advanced demand strategies and supply strategies have to be regarded as alternatives, or if they have to be simultaneously applied, in order to obtain the maximum energy and economic benefit.

  4. Advances in Mobile Data Communications

    Institute of Scientific and Technical Information of China (English)

    Sean Cai; Li Mo

    2011-01-01

    This special issue of ZTE Communications focuses on recent advances in mobile data communications for the ICT and telecommunications industries. The ever-increasing amount of mobile data traffic has beenthe subject of many studies. This research area is widely applicable to contemporary technology and network optimization techniques.

  5. Multiagent reinforcement learning for urban traffic control using coordination graphs

    NARCIS (Netherlands)

    L. Kuyer; S. Whiteson; B. Bakker; N. Vlassis

    2008-01-01

    Since traffic jams are ubiquitous in the modern world, optimizing the behavior of traffic lights for efficient traffic flow is a critically important goal. Though most current traffic lights use simple heuristic protocols, more efficient controllers can be discovered automatically via multiagent rei

  6. Practical experience and results with an advanced on-line gasoline blend optimization system

    Energy Technology Data Exchange (ETDEWEB)

    Serpemen, Y.; Baumeister, K.H.; Hubel, A.; Raichel, P. (Veba Oel Entwicklungs-Gessellschaft mbH, Gelsenkirchen (DE))

    1989-01-01

    Refinery profit margins increased significantly by using the on-line gasoline blend optimization system which allows considerable savings resulting from octane give-away reduction, appreciably enhanced butane utilization, optimum use of the available blend components, and increased operating flexibility by elimination of reblends. The experience with this advanced on-line blending system is described in this paper.

  7. Robust routing mechanisms for intradomain traffic engineering in dynamic networks

    OpenAIRE

    Casas Hernandez, Pedro; Larroca, Federico; Vaton, Sandrine

    2009-01-01

    Internet traffic is highly dynamic and difficult to predict in current network scenarios. This makes of traffic engineering (TE) a very challenging task for network management and resources optimization. We study the problem of intradomain routing optimization under this traffic uncertainty. Recent works have proposed robust optimization techniques to tackle the problem, conceiving the robust routing (RR) approach. RR copes with traffic uncertainty in an off-line preemptive fashion, computing...

  8. Wireless traffic steering for green cellular networks

    CERN Document Server

    Zhang, Shan; Zhou, Sheng; Niu, Zhisheng; Shen, Xuemin (Sherman)

    2016-01-01

    This book introduces wireless traffic steering as a paradigm to realize green communication in multi-tier heterogeneous cellular networks. By matching network resources and dynamic mobile traffic demand, traffic steering helps to reduce on-grid power consumption with on-demand services provided. This book reviews existing solutions from the perspectives of energy consumption reduction and renewable energy harvesting. Specifically, it explains how traffic steering can improve energy efficiency through intelligent traffic-resource matching. Several promising traffic steering approaches for dynamic network planning and renewable energy demand-supply balancing are discussed. This book presents an energy-aware traffic steering method for networks with energy harvesting, which optimizes the traffic allocated to each cell based on the renewable energy status. Renewable energy demand-supply balancing is a key factor in energy dynamics, aimed at enhancing renewable energy sustainability to reduce on-grid energy consum...

  9. Advanced Adaptive Particle Swarm Optimization based SVC Controller for Power System Stability

    Directory of Open Access Journals (Sweden)

    Poonam Singhal

    2014-12-01

    Full Text Available The interconnected systems is continually increasing in size and extending over whole geographical regions, it is becoming increasingly more difficult to maintain synchronism between various parts of the power system. This paper work presents an advanced adaptive Particle swarm optimization technique to optimize the SVC controller parameters for enhancement of the steady state stability & overcoming the premature convergence & stagnation problems as in basic PSO algorithm & Particle swarm optimization with shrinkage factor & inertia weight approach (PSO-SFIWA. In this paper SMIB system along with PID damped SVC controller is considered for study. The generator speed deviation is used as an auxiliary signal to SVC, to generate the desired damping. This controller improves the dynamic performance of power system by reducing the steady-state error. The controller parameters are optimized using basic PSO, PSO-SFIWA & Advanced Adaptive PSO. Computational results show that Advanced Adaptive based SVC controller is able to find better quality solution as compare to conventional PSO & PSO-SFIWA Techniques.

  10. Inter-urban short-term traffic congestion prediction

    OpenAIRE

    Huisken, Giovanni

    2006-01-01

    The main aim of Dynamic Traffic Management is efficient and effective use of the existing traffic infrastructure network. To reach this goal, traffic operators take measures, based on the current traffic situation, control schemes and information services at hand, that (try to) influence and distribute traffic in such a manner that it makes optimal use of the present road infrastructure. In this dissertation, the performances of models that were developed to produce accurate congestion predic...

  11. A Fundamental Study on Area Traffic Control System

    OpenAIRE

    HONDA, Yoshiaki

    1992-01-01

    To save traffic congestion, this report aims at the area traffic control which increasesarea. traffic capacity without expansion of traffic facilities. This method is called AREATRAFFIC CONTROL SYSTEM.Optimum solutions for the area control system are obtained by the use of operationsresearch method. But above calculation time takes too long to fit this optimumregulation to present traffic pattern.In this report, optimization is made by the approximate solution which is composedof the first op...

  12. Optimization method of phase difference for urban traffic arterial control system%城市交通线控系统相位差优化方法

    Institute of Scientific and Technical Information of China (English)

    吕斌; 牛惠民

    2011-01-01

    Based on the random distribution characteristic of link travel speed,the limitations of phase difference optimization methods for the existed arterial control systems were analyzed.Link travel time,vehicle delay and queue length were taken as evaluation indexes,the phase difference optimization algorithm of arterial control system was designed by using information entropy theory and multi-attribute synthetic decision method,and a simulation calculation was carried out.Calculation result indicates that when the variance of link travel speed increases from 5 km·h-1 to 10 km·h-1,link travel speed,vehicle delay and queue length of west-to-east traffic flow increase from 98.4 s,13.5 s·pcu-1 and 9.1 pcu to 115.5 s,15.9 s·pcu-1 and 12.3 pcu respectively.Link travel speed,vehicle delay and queue length of east-to-west traffic flow increase from 99.4 s,13.5 s·pcu-1 and 9.2 pcu to 108.7 s,14.3 s·pcu-1 and 10.8 pcu respectively.So,the random distribution characteristic of link travel speed has an obvious effect on settings of phase difference,and the optimal phase difference can be obtained by using the proposed model.2 tabs,1 fig,13 refs.%根据路段行程车速的随机分布特征,分析了已有线控系统相位差优化方法的局限性。以路段行程时间、车辆延误和排队长度为评价指标,利用信息熵理论和多属性综合决策方法设计了线控系统相位差优化算法,并进行了仿真计算。仿真结果表明:当路段行程车速的方差从5 km.h-1增大到10 km.h-1后,由西向东车流的行程时间、车辆延误和排队长度分别从98.4 s、13.5 s.pcu-1和9.1 pcu增大到115.5 s、15.9 s.pcu-1和12.3 pcu,由东向西车流的行程时间、车辆延误和排队长度分别从99.4 s

  13. Optimizing advanced propeller designs by simultaneously updating flow variables and design parameters

    Science.gov (United States)

    Rizk, Magdi H.

    1988-01-01

    A scheme is developed for solving constrained optimization problems in which the objective function and the constraint function are dependent on the solution of the nonlinear flow equations. The scheme updates the design parameter iterative solutions and the flow variable iterative solutions simultaneously. It is applied to an advanced propeller design problem with the Euler equations used as the flow governing equations. The scheme's accuracy, efficiency and sensitivity to the computational parameters are tested.

  14. Aerodynamic optimization by simultaneously updating flow variables and design parameters with application to advanced propeller designs

    Science.gov (United States)

    Rizk, Magdi H.

    1988-01-01

    A scheme is developed for solving constrained optimization problems in which the objective function and the constraint function are dependent on the solution of the nonlinear flow equations. The scheme updates the design parameter iterative solutions and the flow variable iterative solutions simultaneously. It is applied to an advanced propeller design problem with the Euler equations used as the flow governing equations. The scheme's accuracy, efficiency and sensitivity to the computational parameters are tested.

  15. Research and Application of the Beijing Road Traffic Prediction System

    OpenAIRE

    Ruimin Li; Hongliang Ma; Huapu Lu; Min Guo

    2014-01-01

    As an important part of the urban Advanced Traffic Management Systems (ATMS) and Advanced Traveler Information Systems (ATIS), short-term road traffic prediction system has received special attention in recent decades. The success of ATMS and ATIS technology deployment is heavily dependent on the availability of timely and accurate estimation or prediction of prevailing and emerging traffic conditions. We studied a real-time road traffic prediction system developed for Beijing based on variou...

  16. The car following model considering traffic jerk

    Science.gov (United States)

    Ge, Hong-Xia; Zheng, Peng-jun; Wang, Wei; Cheng, Rong-Jun

    2015-09-01

    Based on optimal velocity car following model, a new model considering traffic jerk is proposed to describe the jamming transition in traffic flow on a highway. Traffic jerk means the sudden braking and acceleration of vehicles, which has a significant impact on traffic movement. The nature of the model is researched by using linear and nonlinear analysis method. A thermodynamic theory is formulated to describe the phase transition and critical phenomenon in traffic flow. The time-dependent Ginzburg-Landau (TDGL) equation and the modified Korteweg-de Vries (mKdV) equation are derived to describe the traffic flow near the critical point and the traffic jam. In addition, the connection between the TDGL and the mKdV equations are also given.

  17. 3rd International Workshop on Advances in Simulation-Driven Optimization and Modeling

    CERN Document Server

    Leifsson, Leifur; Yang, Xin-She

    2016-01-01

    This edited volume is devoted to the now-ubiquitous use of computational models across most disciplines of engineering and science, led by a trio of world-renowned researchers in the field. Focused on recent advances of modeling and optimization techniques aimed at handling computationally-expensive engineering problems involving simulation models, this book will be an invaluable resource for specialists (engineers, researchers, graduate students) working in areas as diverse as electrical engineering, mechanical and structural engineering, civil engineering, industrial engineering, hydrodynamics, aerospace engineering, microwave and antenna engineering, ocean science and climate modeling, and the automotive industry, where design processes are heavily based on CPU-heavy computer simulations. Various techniques, such as knowledge-based optimization, adjoint sensitivity techniques, and fast replacement models (to name just a few) are explored in-depth along with an array of the latest techniques to optimize the...

  18. AMPLE Using BGP Based Traffic Engineering with Admission Control Algorithm

    OpenAIRE

    Dr.V. Palanisamy#1 , K. Gowri

    2013-01-01

    Traffic engineering is an important mechanism for Internet network providers seeking to optimize network performance and traffic delivery. Routing optimization plays a key role in traffic engineering, finding efficient routes so as to achieve the desired network performance. BGP is the de facto protocol used for inter-autonomous system routing in the Internet. BGP has been proven to be secure, efficient, scalable, and robust. In proposed introduced AMPLE – an efficient traffic engineering and...

  19. Traffic at the Edge of Chaos

    OpenAIRE

    K, Nagel; S, Rasmussen

    1995-01-01

    We use a very simple description of human driving behavior to simulate traffic. The regime of maximum vehicle flow in a closed system shows near-critical behavior, and as a result a sharp decrease of the predictability of travel time. Since Advanced Traffic Management Systems (ATMSs) tend to drive larger parts of the transportation system towards this regime of maximum flow, we argue that in consequence the traffic system as a whole will be driven closer to criticality, thus making prediction...

  20. Real-Time Corrected Traffic Correlation Model for Traffic Flow Forecasting

    Directory of Open Access Journals (Sweden)

    Hua-pu Lu

    2015-01-01

    Full Text Available This paper focuses on the problems of short-term traffic flow forecasting. The main goal is to put forward traffic correlation model and real-time correction algorithm for traffic flow forecasting. Traffic correlation model is established based on the temporal-spatial-historical correlation characteristic of traffic big data. In order to simplify the traffic correlation model, this paper presents correction coefficients optimization algorithm. Considering multistate characteristic of traffic big data, a dynamic part is added to traffic correlation model. Real-time correction algorithm based on Fuzzy Neural Network is presented to overcome the nonlinear mapping problems. A case study based on a real-world road network in Beijing, China, is implemented to test the efficiency and applicability of the proposed modeling methods.

  1. Research on Planning & Evaluaion for Track Traffic Under China’s Sustainable Development Strategy

    Institute of Scientific and Technical Information of China (English)

    WuXiaoping

    2004-01-01

    The author advances some basic problems of planning & evaluating for track traffic in the proeess of putting sustainable develop-ment strategy in practice and stresses the study of planning and evaluating methiod system for track traffic and environment strategy.sum-maries and main creative points presented in the thesis are as follows:①The changes of track traffic planning obiects cause by the concept of sustainable development are analyzed;②The theory &?A method of tracd planning optimal decision isset up ;③Environment im-pact assessment for track traffic planning is advanced;⑤Urbun mass transit network plannin is studied;④Planning of intrcity rail sys-tem——the alignment ofptimizattion of deicated passenger line and high speed railway line is studied;⑥An overall evaluation index sys-tem for sustainable development of track traffic planning is estahlished;⑦The track traffie building capacity for sustainable development is studied.Further more,the effect of the mehod and models with empirical studies is verified.The corresponding pplication software is re-alized to provide information service and decision-making support to traffic planning for putting theory into practice.

  2. Network Traffic Prediction Model Based on Mixed Kernels RVM Optimized by CS Algorithm%布谷鸟优化混合核相关向量机的网络流量预测

    Institute of Scientific and Technical Information of China (English)

    陈景柱

    2015-01-01

    In order to improve the prediction accuracy of network traffic , a network traffic prediction model is proposed based on cuckoo searching algorithm optimizing the parameters of mixed kernel relevance vector machine ( CS-RVM) to solve limitations of single kernel function for relevance vector machine .Firstly, the polynomial and Gaussian kernel functions are produced to mixed kernel function for the relevance vector machine , and then the cuckoo searching algorithm is introduced to optimize the parameters of hybrid kernel function , finally network traffic prediction model is established based on the relevance vector machine using the optimal parameters .The simulation results show that , CS-RVM model is of good effect and could improve the prediction accuracy of network traffic .%为了提高网络流量的预测精度,提出一种布谷鸟算法优化混合核相关向量机的网络流量预测模型( CS-RVM )。首先采用多项式和高斯核函数构成混合核函数代替相关向量机的单一核函数,然后引入布谷鸟算法对混合核参数进行寻优,最后建立网络流量预测模型。仿真结果表明,CS-RVM具有良好的建模效果,可提高网络流量的预测精度。

  3. Black-Box Optimization for Buildings and Its Enhancement by Advanced Communication Infrastructure

    Directory of Open Access Journals (Sweden)

    Dimitrios V. ROVAS

    2013-08-01

    Full Text Available The solution of repeated fixed-horizon trajectory optimization problems of processes that are either too difficult or too complex to be described by physics-based models can pose formidable challenges. Very often, soft-computing methods   e.g. black-box modeling and evolutionary optimization   are used. These approaches are ineffective or even computationally intractable for searching high-dimensional parameter spaces. In this paper, a structured iterative process is described for addressing such problems: the starting point is a simple parameterization of the trajectory starting with a reduced number of parameters; after selection of values for these parameters so that this simpler problem is covered satisfactorily, a refinement procedure increases the number of parameters and the optimization is repeated. This continuous parameter refinement and optimization process can yield effective solutions after only a few iterations. To illustrate the applicability of the proposed approach we investigate the problem of dynamic optimization of the operation of HVAC (heating, ventilation, and air conditioning systems, and illustrative simulation results are presented. Finally, the development of advanced communication and interoperability components is described, addressing the problem of how the proposed algorithm could be deployed in realistic contexts.

  4. Rational design and optimization of downstream processes of virus particles for biopharmaceutical applications: current advances.

    Science.gov (United States)

    Vicente, Tiago; Mota, José P B; Peixoto, Cristina; Alves, Paula M; Carrondo, Manuel J T

    2011-01-01

    The advent of advanced therapies in the pharmaceutical industry has moved the spotlight into virus-like particles and viral vectors produced in cell culture holding great promise in a myriad of clinical targets, including cancer prophylaxis and treatment. Even though a couple of cases have reached the clinic, these products have yet to overcome a number of biological and technological challenges before broad utilization. Concerning the manufacturing processes, there is significant research focusing on the optimization of current cell culture systems and, more recently, on developing scalable downstream processes to generate material for pre-clinical and clinical trials. We review the current options for downstream processing of these complex biopharmaceuticals and underline current advances on knowledge-based toolboxes proposed for rational optimization of their processing. Rational tools developed to increase the yet scarce knowledge on the purification processes of complex biologicals are discussed as alternative to empirical, "black-boxed" based strategies classically used for process development. Innovative methodologies based on surface plasmon resonance, dynamic light scattering, scale-down high-throughput screening and mathematical modeling for supporting ion-exchange chromatography show great potential for a more efficient and cost-effective process design, optimization and equipment prototyping. PMID:21784144

  5. Optimized CANDU-6 cell and reactivity device supercell models for advanced fuels reactor database generation

    International Nuclear Information System (INIS)

    Highlights: • Propose an optimize 2-D model for CANDU lattice cell. • Propose a new 3-D simulation model for CANDU reactivity devices. • Implement other acceleration techniques for reactivity device simulations. • Reactivity device incremental cross sections for advanced CANDU fuels with thorium. - Abstract: Several 2D cell and 3D supercell models for reactivity device simulation have been proposed along the years for CANDU-6 reactors to generate 2-group cross section databases for finite core calculations in diffusion. Although these models are appropriate for natural uranium fuel, they are either too approximate or too expensive in terms of computer time to be used for optimization studies of advanced fuel cycles. Here we present a method to optimize the 2D spatial mesh to be used for a collision probability solution of the transport equation for CANDU cells. We also propose a technique to improve the modeling and accelerate the evaluation, in deterministic transport theory, of the incremental cross sections and diffusion coefficients associated with reactivity devices required for reactor calculations

  6. Estimation of carbon dioxide emissions per urban center link unit using data collected by the Advanced Traffic Information System in Daejeon, Korea

    Science.gov (United States)

    Ryu, B. Y.; Jung, H. J.; Bae, S. H.; Choi, C. U.

    2013-12-01

    CO2 emissions on roads in urban centers substantially affect global warming. It is important to quantify CO2 emissions in terms of the link unit in order to reduce these emissions on the roads. Therefore, in this study, we utilized real-time traffic data and attempted to develop a methodology for estimating CO2 emissions per link unit. Because of the recent development of the vehicle-to-infrastructure (V2I) communication technology, data from probe vehicles (PVs) can be collected and speed per link unit can be calculated. Among the existing emission calculation methodologies, mesoscale modeling, which is a representative modeling measurement technique, requires speed and traffic data per link unit. As it is not feasible to install fixed detectors at every link for traffic data collection, in this study, we developed a model for traffic volume estimation by utilizing the number of PVs that can be additionally collected when the PV data are collected. Multiple linear regression and an artificial neural network (ANN) were used for estimating the traffic volume. The independent variables and input data for each model are the number of PVs, travel time index (TTI), the number of lanes, and time slots. The result from the traffic volume estimate model shows that the mean absolute percentage error (MAPE) of the ANN is 18.67%, thus proving that it is more effective. The ANN-based traffic volume estimation served as the basis for the calculation of emissions per link unit. The daily average emissions for Daejeon, where this study was based, were 2210.19 ton/day. By vehicle type, passenger cars accounted for 71.28% of the total emissions. By road, Gyeryongro emitted 125.48 ton/day, accounting for 5.68% of the total emission, the highest percentage of all roads. In terms of emissions per kilometer, Hanbatdaero had the highest emission volume, with 7.26 ton/day/km on average. This study proves that real-time traffic data allow an emissions estimate in terms of the link unit

  7. Optimization of time distribution for studying the course modules on advanced training of health care administrators

    Directory of Open Access Journals (Sweden)

    Dorovskaya A.l.

    2015-06-01

    Full Text Available The research objective is rational (optimal time management in studying the course modules on Advanced Training of Health Care Administrators. Materials and methods. We conducted expert survey of 73 healthcare administrators from medical organizations of Saratov region. Branch-and-bound method was used for rescheduling the educational program. Results. Both direct and inverse problems have been solved. The direct one refers to time distribution for each module of the advanced Training of Healthcare Administrators course so that the total score is maximum and each module is marked not lower than "satisfactory". The inverse one resulted in achieving minimal time characteristics for varieties of average score. Conclusion. The offered approach allows to solve problems of managing time given for education.

  8. An Evolutionary Algorithm with Advanced Goal and Priority Specification for Multi-objective Optimization

    CERN Document Server

    Khor, E F; Sathikannan, R; Tan, K C; 10.1613/jair.842

    2011-01-01

    This paper presents an evolutionary algorithm with a new goal-sequence domination scheme for better decision support in multi-objective optimization. The approach allows the inclusion of advanced hard/soft priority and constraint information on each objective component, and is capable of incorporating multiple specifications with overlapping or non-overlapping objective functions via logical 'OR' and 'AND' connectives to drive the search towards multiple regions of trade-off. In addition, we propose a dynamic sharing scheme that is simple and adaptively estimated according to the on-line population distribution without needing any a priori parameter setting. Each feature in the proposed algorithm is examined to show its respective contribution, and the performance of the algorithm is compared with other evolutionary optimization methods. It is shown that the proposed algorithm has performed well in the diversity of evolutionary search and uniform distribution of non-dominated individuals along the final trade...

  9. Optimization of an Advanced Hybrid Wing Body Concept Using HCDstruct Version 1.2

    Science.gov (United States)

    Quinlan, Jesse R.; Gern, Frank H.

    2016-01-01

    Hybrid Wing Body (HWB) aircraft concepts continue to be promising candidates for achieving the simultaneous fuel consumption and noise reduction goals set forth by NASA's Environmentally Responsible Aviation (ERA) project. In order to evaluate the projected benefits, improvements in structural analysis at the conceptual design level were necessary; thus, NASA researchers developed the Hybrid wing body Conceptual Design and structural optimization (HCDstruct) tool to perform aeroservoelastic structural optimizations of advanced HWB concepts. In this paper, the authors present substantial updates to the HCDstruct tool and related analysis, including: the addition of four inboard and eight outboard control surfaces and two all-movable tail/rudder assemblies, providing a full aeroservoelastic analysis capability; the implementation of asymmetric load cases for structural sizing applications; and a methodology for minimizing control surface actuation power using NASTRAN SOL 200 and HCDstruct's aeroservoelastic finite-element model (FEM).

  10. Advances in the integration of drug metabolism into the lead optimization paradigm.

    Science.gov (United States)

    Korfmacher, Walter A

    2009-06-01

    The lead optimization paradigm includes a team of experts that has a multitude of parameters to consider when moving from an initial lead compound through the lead optimization phase to the development phase. While in the past the team may have had only a medicinal chemist and a pharmacologist, the current team would often include experts in the areas of drug metabolism and pharmacokinetics (DMPK) as well as chemical toxicity. This review provides an overview of the some of the recent advances in the areas of DMPK screening plus a discussion of some of the assays that can be used to begin to screen for toxicity issues. The focus of this review is the major potential problem areas: oral bioavailability, half-life, drug-drug interactions and metabolism and toxicity issues. PMID:19519496

  11. Optimizing spinning time-domain gravitational waveforms for advanced LIGO data analysis

    Science.gov (United States)

    Devine, Caleb; Etienne, Zachariah B.; McWilliams, Sean T.

    2016-06-01

    The spinning effective-one-body–numerical relativity (SEOBNR) series of gravitational wave approximants are among the best available for advanced LIGO data analysis. Unfortunately, SEOBNR codes as they currently exist within LALSuite are generally too slow to be directly useful for standard Markov-chain Monte Carlo-based parameter estimation (PE). Reduced-order models (ROMs) of SEOBNR have been developed for this purpose, but there is no known way to make ROMs of the full eight-dimensional intrinsic parameter space more efficient for PE than the SEOBNR codes directly. So as a proof of principle, we have sped up the original LALSuite SEOBNRv2 approximant code, which models waveforms from aligned-spin systems, by nearly 300x. Our optimized code shortens the timescale for conducting PE with this approximant to months, assuming a purely serial analysis, so that even modest parallelization combined with our optimized code will make running the full PE pipeline with SEOBNR codes directly a realistic possibility. A number of our SEOBNRv2 optimizations have already been applied to SEOBNRv3, a new approximant capable of modeling sources with all eight (precessing) intrinsic degrees of freedom. We anticipate that once all of our optimizations have been applied to SEOBNRv3, a similar speed-up may be achieved.

  12. Traffic Flow Management Wrap-Up

    Science.gov (United States)

    Grabbe, Shon

    2011-01-01

    Traffic Flow Management involves the scheduling and routing of air traffic subject to airport and airspace capacity constraints, and the efficient use of available airspace. Significant challenges in this area include: (1) weather integration and forecasting, (2) accounting for user preferences in the Traffic Flow Management decision making process, and (3) understanding and mitigating the environmental impacts of air traffic on the environment. To address these challenges, researchers in the Traffic Flow Management area are developing modeling, simulation and optimization techniques to route and schedule air traffic flights and flows while accommodating user preferences, accounting for system uncertainties and considering the environmental impacts of aviation. This presentation will highlight some of the major challenges facing researchers in this domain, while also showcasing recent innovations designed to address these challenges.

  13. Traffic and Granular Flow ’07

    CERN Document Server

    Chevoir, François; Gondret, Philippe; Lassarre, Sylvain; Lebacque, Jean-Patrick; Schreckenberg, Michael

    2009-01-01

    This book covers several research fields, all of which deal with transport. Three main topics are treated: road traffic, granular matter, and biological transport. Different points of view, i.e. modelling, simulations, experiments, and phenomenological observations, are considered. Sub-topics include: highway or urban vehicular traffic (dynamics of traffic, macro/micro modelling, measurements, data analysis, security issues, psychological issues), pedestrian traffic, animal traffic (e.g. social insects), collective motion in biological systems (molecular motors...), granular flow (dense flows, intermittent flows, solid/liquid transition, jamming, force networks, fluid and solid friction), networks (biological networks, urban traffic, the internet, vulnerability of networks, optimal transport networks) and cellular automata applied to the various aforementioned fields.

  14. Traffic Engineering without Congestion Hot Spots in MPLS

    Directory of Open Access Journals (Sweden)

    A.Padmapriya,

    2010-10-01

    Full Text Available Traffic Engineering [1] broadly relates to optimization of the performance of the operational IP network. In networking, network congestion occurs when a link or node is carrying so much data that its quality of service deteriorates. Typical effects include queueing delay, packet loss or the blocking of new connections. A consequence of these latter two is that incremental increases in offered load lead either only to small increases in network throughput, or to an actual reduction in network throughput. This paper discusses methods like PNP approach [2] and HITS method for improving QoS [3], which are used for traffic engineering in MPLS. This paper will examine the two approaches; discuss solutions in both PNP approach and HITS method for improving QoS and point to topics for research and advanced development.

  15. Concepts and algorithms for terminal-area traffic management

    Science.gov (United States)

    Erzberger, H.; Chapel, J. D.

    1984-01-01

    The nation's air-traffic-control system is the subject of an extensive modernization program, including the planned introduction of advanced automation techniques. This paper gives an overview of a concept for automating terminal-area traffic management. Four-dimensional (4D) guidance techniques, which play an essential role in the automated system, are reviewed. One technique, intended for on-board computer implementation, is based on application of optimal control theory. The second technique is a simplified approach to 4D guidance intended for ground computer implementation. It generates advisory messages to help the controller maintain scheduled landing times of aircraft not equipped with on-board 4D guidance systems. An operational system for the second technique, recently evaluated in a simulation, is also described.

  16. Formation of density waves in traffic flow through intersecting roads.

    Science.gov (United States)

    Ray, B; Bhattacharyya, S N

    2006-03-01

    The formation of density waves in two intersecting roads, with a traffic circle at the intersection, is studied. It is found that, depending on the traffic densities in the two roads, density waves can form in the traffic circle and in one or both of the roads. Depending on the expression chosen for the optimal velocity, either the congestion moves entirely to the traffic circle or the congestion becomes confined to the traffic circle and a part of the road approaching the traffic circle. PMID:16605592

  17. Traffic congestion in interconnected complex networks

    CERN Document Server

    Tan, Fei; Xia, Yongxiang; Tse, Chi K

    2014-01-01

    Traffic congestion in isolated complex networks has been investigated extensively over the last decade. Coupled network models have recently been developed to facilitate further understanding of real complex systems. Analysis of traffic congestion in coupled complex networks, however, is yet to come. In this paper, we try to explore the effect of interconnections on traffic congestion in interconnected BA scale-free networks. We find that assortative coupling can alleviate traffic congestion better than disassortative and random coupling when the node processing capacity is allocated based on node usage probability. Furthermore, the optimal coupling probability can be found for assortative coupling. However, three types of coupling preferences achieve similar traffic performance if all nodes share the same processing capacity. We analyze interconnected Internet AS-level graphs of Japan and South Korea and obtain similar results. Some practical suggestions are presented to optimize such real-world interconnect...

  18. A Kalman filter approach for exploiting bluetooth traffic data when estimating time-dependent OD matrices

    OpenAIRE

    Barceló Bugeda, Jaime; Montero Mercadé, Lídia; Bullejos, Manuel; Serch Muni, Oriol; Carmona, Carlos

    2013-01-01

    Time-dependent origin–destination (OD) matrices are essential input for dynamic traffic models such as microscopic and mesoscopic traffic simulators. Dynamic traffic models also support real-time traffic management decisions, and they are traditionally used in the design and evaluation of advanced traffic traffic management and information systems (ATMS/ATIS). Time-dependent OD estimations are typically based either on Kalman filtering or on bilevel mathematical programming, which can be cons...

  19. Development and Evaluation of a Control System for Regional Traffic Management

    OpenAIRE

    McLin, John L.; William T. Scherer

    2011-01-01

    Traffic congestion is a worsening problem in metropolitan areas which will require integrated regional traffic control systems to improve traffic conditions. This paper presents a regional traffic control system which can detect incident conditions and provide integrated traffic management during nonrecurrent congestion events. The system combines advanced artificial intelligence techniques with a traffic performance model based on HCM equations. Preliminary evaluation of the control system u...

  20. Bound Maxima as a Traffic Feature under DDOS Flood Attacks

    Directory of Open Access Journals (Sweden)

    Jie Xue

    2012-01-01

    Full Text Available This paper gives a novel traffic feature for identifying abnormal variation of traffic under DDOS flood attacks. It is the histogram of the maxima of the bounded traffic rate on an interval-by-interval basis. We use it to experiment on the traffic data provided by MIT Lincoln Laboratory under Defense Advanced Research Projects Agency (DARPA in 1999. The experimental results profitably enhance the evidences that traffic rate under DDOS attacks is statistically higher than that of normal traffic considerably. They show that the pattern of the histogram of the maxima of bounded rate of attack-contained traffic greatly differs from that of attack-free traffic. Besides, the present traffic feature is simple in mathematics and easy to use in practice.

  1. Modelling traveler information and its effects on traffic

    OpenAIRE

    Nguyen, Thai Phu

    2010-01-01

    Traffic conditions on a road network often suffer from congestion. According to sources, the traffic congestion can be classified into two categories : recurrent congestion determined by the physic laws of traffic and non-recurrent congestion due to incidents, accidents or other hazards on the road. Thanks to the advancement of technologies, including computers, communications and data processing, the traffic operator is now able to detect disturbances, to measure the effects and even to anti...

  2. REAL TIME TRAFFIC LIGHT CONTROL USING IMAGE PROCESSING

    OpenAIRE

    PALLAVI CHOUDEKAR,; SAYANTI BANERJEE,; M.K.MUJU

    2011-01-01

    As the problem of urban traffic congestion spreads, there is a pressing need for the introduction of advanced technology and equipment to improve the state-of-the-art of traffic control. Traffic problems nowadays are increasing because of the growing number of vehicles and the limited resources provided by current nfrastructures. The simplest way for controlling a traffic light uses timer for each phase. Another way is to use electronic sensors in order to detect vehicles, and produce signal...

  3. Significance of sensor location in real-time traffic state estimation

    OpenAIRE

    Ahmed, A.; Watling, D; Ngoduy, D

    2014-01-01

    Short-term congestion caused due to traffic incidents or other road environment factors significantly reduces traffic flow capacity of a link which forms a major part of travel time delays. Accurate and reliable estimate of real-time traffic state is essential for optimizing network performance during unpredictable events. Inaccurate estimate of current traffic state produces unreliable travel-time estimations which lead to ineffective traffic management strategies during traffic incident. Th...

  4. Outer Synchronization between Two Coupled Complex Networks and Its Application in Public Traffic Supernetwork

    OpenAIRE

    Du, Wen-ju; Zhang, Jian-gang; An, Xin-lei; Qin, Shuang; Yu, Jian-ning

    2016-01-01

    The paper presents a new urban public traffic supernetwork model by using the existing bus network modeling method, consisting of the conventional bus traffic network and the urban rail traffic network. We investigate the synchronization problem of urban public traffic supernetwork model by using the coupled complex network’s outer synchronization theory. Analytical and numerical simulations are given to illustrate the impact of traffic dispatching frequency and traffic lines optimization to ...

  5. Anticipated Traffic Jam Locations Using Inlet and Outlet Factors Analysis

    OpenAIRE

    Kenedy Aliila Greyson

    2012-01-01

    The traffic congestion is a common event during rush-hours in big cities. Costs imposed by the traffic congestion and traffic jams to the road users include: more fuel consumption, more time spent on the road, more environmental pollution, etc. This research aims at the optimization of the available capacity of the road network (infrastructure) using coordinated traffic lights. The analysis used here is a projected outcome of the road sector status during rush hours (the worse case road situa...

  6. Jamitons: Phantom Traffic Jams

    Science.gov (United States)

    Kowszun, Jorj

    2013-01-01

    Traffic on motorways can slow down for no apparent reason. Sudden changes in speed by one or two drivers can create a chain reaction that causes a traffic jam for the vehicles that are following. This kind of phantom traffic jam is called a "jamiton" and the article discusses some of the ways in which traffic engineers produce…

  7. 基于流量熵的道路交通网络脆弱性优化%On Vulnerable Optimization of Traffic Road Network Based on Flow Entropy

    Institute of Scientific and Technical Information of China (English)

    曹娟; 张颖淳; 苏伯洪

    2014-01-01

    道路交通系统是社会物流实现的重要支撑,其中重要站点的故障可能造成交通系统的运营限于瘫痪,甚至产生重大的经济影响。针对道路交通网络中的相继故障问题,从动静结合的角度分析了道路交通网络的脆弱性。为了检测道路交通网络在相继故障下的脆弱性动态变化,首先建立了道路交通网络的级联反应动力学模型;然后提出该模型中脆弱性的优化设计方案,并利用算法进化得到网络的最优设计;最后利用复杂网络理论得到道路交通网络的网络结构图,通过该算例验证了提出的模型和优化方法的有效性和实际应用性。仿真实验表明该模型和方法能有效地降低交通网络的脆弱性。%Road traffic system is an important support for social logistics .The failure of a significant site may result in the paralysis of the w hole traffic system ,and even cause a significant economic damage .In this paper ,the dynamical vulnerability of the road traffic network has been explored according to the suc-cessive failures within the system .First ,a cascade reaction model of the road traffic network has been es-tablished for detecting dynamical changes of the network vulnerability facing successive failures .Then an optimal design of the model has been proposed based on evolutionary algorithm .Finally ,the complex net-work theory is applied to obtain the network structure of a road network .And this case study is given to verify the effectiveness and practical application of the proposed model and optimization algorithm .Simula-tion results show that the proposed method can effectively reduce the vulnerability of the road traffic net-work .

  8. Advanced CANDU reactors fuel analysis through optimal fuel management at approach to refuelling equilibrium

    International Nuclear Information System (INIS)

    The analysis of alternate CANDU fuels along with natural uranium-based fuel was carried out from the view point of optimal in-core fuel management at approach to refuelling equilibrium. The alternate fuels considered in the present work include thorium containing oxide mixtures (MOX), plutonium-based MOX, and Pressurised Water Reactor (PWR) spent fuel recycled in CANDU reactors (Direct Use of spent PWR fuel in CANDU (DUPIC)); these are compared with the usual natural UO2 fuel. The focus of the study is on the 'Approach to Refuelling Equilibrium' period which immediately follows the initial commissioning of the reactor. The in-core fuel management problem for this period is treated as an optimization problem in which the objective function is the refuelling frequency to be minimized by adjusting the following decision variables: the channel to be refuelled next, the time of the refuelling and the number of fresh fuel bundles to be inserted in the channel. Several constraints are also included in the optimisation problem which is solved using Perturbation Theory. Both the present 37-rod CANDU fuel bundle and the proposed CANFLEX bundle designs are part of this study. The results include the time to reach refuelling equilibrium from initial start-up of the reactor, the average discharge burnup, the average refuelling frequency and the average channel and bundle powers relative to natural UO2. The model was initially tested and the average discharge burnup for natural UO2 came within 2% of the industry accepted 199 MWh/kgHE. For this type of fuel, the optimization exercise predicted the savings of 43 bundles per full power year. In addition to producing average discharge burnups and other parameters for the advanced fuels investigated, the optimisation model also evidenced some problem areas like high power densities for fuels such as the DUPIC. Perturbation Theory has proven itself to be an accurate and valuable optimization tool in predicting the time between

  9. TRANSIMS traffic flow characteristics

    OpenAIRE

    Nagel, Kai; Stretz, Paula; Pieck, Martin; Donnelly, Rick; Barrett, Christopher L.

    1997-01-01

    Knowledge of fundamental traffic flow characteristics of traffic simulation models is an essential requirement when using these models for the planning, design, and operation of transportation systems. In this paper we discuss the following: a description of how features relevant to traffic flow are currently under implementation in the TRANSIMS microsimulation, a proposition for standardized traffic flow tests for traffic simulation models, and the results of these tests for two different ve...

  10. 基于粒子群优化偏最小二乘的铁路客运量预测%Forecast of railway passenger traffic based on PLS of particle swarm optimization

    Institute of Scientific and Technical Information of China (English)

    梁小林; 杜晓慧

    2014-01-01

    By analyzing the influence factors of railway passenger traffic from 1997 to 2007, partial least-squares regression model were established, then actual and predicted values of railway passenger traffic were compared, and the model prediction error was relatively high. In order to improve the prediction accuracy of the model, PSO optimization algorithm was adopted to optimize the regression coefficients, then a new model was got. Upon examination, the prediction error of the model dropped to 1.01%from original 3.04%. Finally the railway passenger traffic from 2013 to 2014 which we use this model to predict were 2 109.705 million and 2 273.688 million.%通过对1997-2012年铁路客运量的影响因素进行分析,建立偏最小二乘回归模型,并用实际的铁路客运量与预测值进行比较,检验出模型的预测误差较大.为了提高模型的预测精度,采取粒子群优化算法优化回归系数,得到一个新的模型.经检验,该模型的预测误差由原模型的3.04%降到1.01%.最后用该模型预测出2013-2014年的铁路客运量分别为210.9705千万人和227.3688千万人.

  11. OPTIMA: advanced methods for the analysis, integration, and optimization of PRISMA mission products

    Science.gov (United States)

    Guzzi, Donatella; Pippi, Ivan; Aiazzi, Bruno; Baronti, Stefano; Carlà, Roberto; Lastri, Cinzia; Nardino, Vanni; Raimondi, Valentina; Santurri, Leonardo; Selva, Massimo; Alparone, Luciano; Garzelli, Andrea; Lopinto, Ettore; Ananasso, Cristina; Barducci, Alessandro

    2015-10-01

    PRISMA is an Earth observation system that combines a hyperspectral sensor with a panchromatic, medium-resolution camera. OPTIMA is one of the five independent scientific research projects funded by the Italian Space Agency in the framework of PRISMA mission for the development of added-value algorithms and advanced applications. The main goal of OPTIMA is to increase and to strengthen the applications of PRISMA through the implementation of advanced methodologies for the analysis, integration and optimization of level 1 and 2 products. The project is comprehensive of several working packages: data simulation, data quality, data optimization, data processing and integration and, finally, evaluation of some applications related to natural hazards. Several algorithms implemented during the project employ high-speed autonomous procedures for the elaboration of the upcoming images acquired by PRISMA. To assess the performances of the developed algorithms and products, an end-to-end simulator of the instrument has been implemented. Data quality analysis has been completed by introducing noise modeling. Stand-alone procedures of radiometric and atmospheric corrections have been developed, allowing the retrieval of at-ground spectral reflectance maps. Specific studies about image enhancement, restoration and pan-sharpening have been carried out for providing added-value data. Regarding the mission capability of monitoring environmental processes and disasters, different techniques for estimating surface humidity and for analyzing burned areas have been investigated. Finally, calibration and validation activities utilizing the CAL/VAL test site managed by CNR-IFAC and located inside the Regional Park of San Rossore (Pisa), Italy have been considered.

  12. Research Advances in Urban Traffic Information Detection Technologies Based on Smartphone Applications%基于智能手机应用的城市交通信息检测技术研究进展

    Institute of Scientific and Technical Information of China (English)

    欧梦宁; 张利国

    2016-01-01

    Mobile sensing technology based on smartphones is an emerging direction and a hot spot in the field of urban traffic information detection, and it is also an important part of the big traffic data. Relying on the powerful mobile communication technology of smartphones and the environmental perception ability of various embedded sensors, we can obtain microcosmic information,such as real-time position, attitude dynamics of traffic participants, and even traffic scene. In this paper, we reviewed the advances in smartphones based on traffic information acquisition, parameter detection, and information service. We Also discussed the challenges and solutions that the smartphones faced in this field, like energy dissipation, detection data deviation, as well as user's personal privacy and security. We also elaborated several future research directions in this field.%基于智能手机应用的移动传感技术是城市交通信息检测领域的一个新兴方向和研究热点,也是交通大数据研究的重要组成部分.依靠智能手机强大的移动通讯技术,以及各种嵌入式传感器的环境感知能力,就能够实时获取到交通参与者的位置、姿态、动态、甚至交通场景等各种微观信息.本文结合当前智能手机传感器件的标准配置状况,综述了智能手机应用在交通信息获取、交通参数检测、交通信息服务等方面的研究进展.同时分析了智能手机在能量损耗、检测数据偏差以及用户个人隐秘与安全等应用中面临的挑战,并讨论了对应的解决方法.最后,对未来的研究发展趋势进行展望.

  13. Improved Broadband Liner Optimization Applied to the Advanced Noise Control Fan

    Science.gov (United States)

    Nark, Douglas M.; Jones, Michael G.; Sutliff, Daniel L.; Ayle, Earl; Ichihashi, Fumitaka

    2014-01-01

    The broadband component of fan noise has grown in relevance with the utilization of increased bypass ratio and advanced fan designs. Thus, while the attenuation of fan tones remains paramount, the ability to simultaneously reduce broadband fan noise levels has become more desirable. This paper describes improvements to a previously established broadband acoustic liner optimization process using the Advanced Noise Control Fan rig as a demonstrator. Specifically, in-duct attenuation predictions with a statistical source model are used to obtain optimum impedance spectra over the conditions of interest. The predicted optimum impedance information is then used with acoustic liner modeling tools to design liners aimed at producing impedance spectra that most closely match the predicted optimum values. Design selection is based on an acceptance criterion that provides the ability to apply increased weighting to specific frequencies and/or operating conditions. Constant-depth, double-degree of freedom and variable-depth, multi-degree of freedom designs are carried through design, fabrication, and testing to validate the efficacy of the design process. Results illustrate the value of the design process in concurrently evaluating the relative costs/benefits of these liner designs. This study also provides an application for demonstrating the integrated use of duct acoustic propagation/radiation and liner modeling tools in the design and evaluation of novel broadband liner concepts for complex engine configurations.

  14. Advanced fuel for fast breeder reactors: Fabrication and properties and their optimization

    International Nuclear Information System (INIS)

    The present design for FBR fuel rods includes usually MOX fuel pellets cladded into stainless steel tubes, together with UO2 axial blanket and stainless steel hexagonal wrappers. Mixed carbide, nitride and metallic fuels have been tested as alternative fuels in test reactors. Among others, the objectives to develop these alternative fuels are to gain a high breeding ratio, short doubling time and high linear ratings. Fuel rod and assembly designers are now concentrating on finding the combination of optimized fuel, cladding and wrapper materials which could result in improvement of fuel operational reliability under high burnups and load-follow mode of operation. The purpose of the meeting was to review the experience of advanced FBR fuel fabrication technology, its properties before, under and after irradiation, peculiarities of the back-end of the nuclear fuel cycle, and to outline future trends. As a result of the panel discussion, the recommendations on future Agency activities in the area of advanced FBR fuels were developed. A separate abstract was prepared for each of the 10 presentations of this meeting. Refs, figs and tabs

  15. Optimizing spinning time-domain gravitational waveforms for Advanced LIGO data analysis

    CERN Document Server

    Devine, Caleb; McWilliams, Sean T

    2016-01-01

    The Spinning Effective One Body-Numerical Relativity (SEOBNR) series of gravitational wave approximants are among the best available for Advanced LIGO data analysis. Unfortunately, SEOBNR codes as they currently exist within LALSuite are generally too slow to be directly useful for standard Markov-Chain Monte Carlo-based parameter estimation (PE). Reduced-Order Models (ROMs) of SEOBNR have been developed for this purpose, but there is no known way to make ROMs of the full eight-dimensional intrinsic parameter space more efficient for PE than the SEOBNR codes directly. So as a proof of principle, we have sped up the original LALSuite SEOBNRv2 approximant code, which models waveforms from aligned-spin systems, by about 280x. Our optimized code shortens the timescale for conducting PE with this approximant to months, assuming a purely serial analysis, so that even modest parallelization combined with our optimized code will make running the full PE pipeline with SEOBNR codes directly a realistic possibility. A n...

  16. Technology-design-manufacturing co-optimization for advanced mobile SoCs

    Science.gov (United States)

    Yang, Da; Gan, Chock; Chidambaram, P. R.; Nallapadi, Giri; Zhu, John; Song, S. C.; Xu, Jeff; Yeap, Geoffrey

    2014-03-01

    How to maintain the Moore's Law scaling beyond the 193 immersion resolution limit is the key question semiconductor industry needs to answer in the near future. Process complexity will undoubtfully increase for 14nm node and beyond, which brings both challenges and opportunities for technology development. A vertically integrated design-technologymanufacturing co-optimization flow is desired to better address the complicated issues new process changes bring. In recent years smart mobile wireless devices have been the fastest growing consumer electronics market. Advanced mobile devices such as smartphones are complex systems with the overriding objective of providing the best userexperience value by harnessing all the technology innovations. Most critical system drivers are better system performance/power efficiency, cost effectiveness, and smaller form factors, which, in turns, drive the need of system design and solution with More-than-Moore innovations. Mobile system-on-chips (SoCs) has become the leading driver for semiconductor technology definition and manufacturing. Here we highlight how the co-optimization strategy influenced architecture, device/circuit, process technology and package, in the face of growing process cost/complexity and variability as well as design rule restrictions.

  17. Advanced and flexible genetic algorithms for BWR fuel loading pattern optimization

    International Nuclear Information System (INIS)

    This work proposes advances in the implementation of a flexible genetic algorithm (GA) for fuel loading pattern optimization for Boiling Water Reactors (BWRs). In order to avoid specific implementations of genetic operators and to obtain a more flexible treatment, a binary representation of the solution was implemented; this representation had to take into account that a little change in the genotype must correspond to a little change in the phenotype. An identifier number is assigned to each assembly by means of a Gray Code of 7 bits and the solution (the loading pattern) is represented by a binary chain of 777 bits of length. Another important contribution is the use of a Fitness Function which includes a Heuristic Function and an Objective Function. The Heuristic Function which is defined to give flexibility on the application of a set of positioning rules based on knowledge, and the Objective Function that contains all the parameters which qualify the neutronic and thermal hydraulic performances of each loading pattern. Experimental results illustrating the effectiveness and flexibility of this optimization algorithm are presented and discussed.

  18. A Marine Traffic Flow Model

    OpenAIRE

    Tsz Leung Yip

    2013-01-01

    A model is developed for studying marine traffic flow through classical traffic flow theories, which can provide us with a better understanding of the phenomenon of traffic flow of ships. On one hand, marine traffic has its special features and is fundamentally different from highway, air and pedestrian traffic. The existing traffic models cannot be simply extended to marine traffic without addressing marine traffic features. On the other hand, existing literature on marine traffic focuses on...

  19. SELF-SIMILAR TRAFFIC GENERATOR

    OpenAIRE

    Linawati Linawati; I Made Suartika

    2009-01-01

    Network traffic generator can be produced using OPNET. OPNET generates the traffic as explicit traffic or background traffic. This paper demonstrates generating traffic in OPNET 7.0 as background traffic. The traffi generator that was simulated is self-similar traffic with different Hurst parameter. The simulation results proved that OPNET with background traffic function can be as a qualified self-similar traffic generator. These results can help in investigating and analysing network perfor...

  20. A Sarsa(λ-Based Control Model for Real-Time Traffic Light Coordination

    Directory of Open Access Journals (Sweden)

    Xiaoke Zhou

    2014-01-01

    Full Text Available Traffic problems often occur due to the traffic demands by the outnumbered vehicles on road. Maximizing traffic flow and minimizing the average waiting time are the goals of intelligent traffic control. Each junction wants to get larger traffic flow. During the course, junctions form a policy of coordination as well as constraints for adjacent junctions to maximize their own interests. A good traffic signal timing policy is helpful to solve the problem. However, as there are so many factors that can affect the traffic control model, it is difficult to find the optimal solution. The disability of traffic light controllers to learn from past experiences caused them to be unable to adaptively fit dynamic changes of traffic flow. Considering dynamic characteristics of the actual traffic environment, reinforcement learning algorithm based traffic control approach can be applied to get optimal scheduling policy. The proposed Sarsa(λ-based real-time traffic control optimization model can maintain the traffic signal timing policy more effectively. The Sarsa(λ-based model gains traffic cost of the vehicle, which considers delay time, the number of waiting vehicles, and the integrated saturation from its experiences to learn and determine the optimal actions. The experiment results show an inspiring improvement in traffic control, indicating the proposed model is capable of facilitating real-time dynamic traffic control.

  1. A Sarsa(λ)-based control model for real-time traffic light coordination.

    Science.gov (United States)

    Zhou, Xiaoke; Zhu, Fei; Liu, Quan; Fu, Yuchen; Huang, Wei

    2014-01-01

    Traffic problems often occur due to the traffic demands by the outnumbered vehicles on road. Maximizing traffic flow and minimizing the average waiting time are the goals of intelligent traffic control. Each junction wants to get larger traffic flow. During the course, junctions form a policy of coordination as well as constraints for adjacent junctions to maximize their own interests. A good traffic signal timing policy is helpful to solve the problem. However, as there are so many factors that can affect the traffic control model, it is difficult to find the optimal solution. The disability of traffic light controllers to learn from past experiences caused them to be unable to adaptively fit dynamic changes of traffic flow. Considering dynamic characteristics of the actual traffic environment, reinforcement learning algorithm based traffic control approach can be applied to get optimal scheduling policy. The proposed Sarsa(λ)-based real-time traffic control optimization model can maintain the traffic signal timing policy more effectively. The Sarsa(λ)-based model gains traffic cost of the vehicle, which considers delay time, the number of waiting vehicles, and the integrated saturation from its experiences to learn and determine the optimal actions. The experiment results show an inspiring improvement in traffic control, indicating the proposed model is capable of facilitating real-time dynamic traffic control. PMID:24592183

  2. Characteristics of vehicular traffic flow at a roundabout

    Science.gov (United States)

    Ebrahim Fouladvand, M.; Sadjadi, Zeinab; Reza Shaebani, M.

    2004-10-01

    We construct a stochastic cellular automata model for the description of vehicular traffic at a roundabout designed at the intersection of two perpendicular streets. The vehicular traffic is controlled by a self-organized scheme in which traffic lights are absent. This controlling method incorporates a yield-at-entry strategy for the approaching vehicles to the circulating traffic flow in the roundabout. Vehicular dynamics is simulated and the delay experienced by the traffic at each individual street is evaluated. We discuss the impact of the geometrical properties of the roundabout on the total delay. We compare our results with traffic-light signalization schemes, and obtain the critical traffic volume over which the intersection is optimally controlled through traffic-light signalization schemes.

  3. Automated Negotiation for Traffic Regulation

    OpenAIRE

    Gaciarz, Matthis; Aknine, Samir; BHOURI, Neila

    2015-01-01

    Urban congestion is a major problem in our society for quality of life and for productivity. The increasing communication abilities of vehicles and recent advances in artificial intelligence allow new solutions to be considered for traffic regulation, based on real-time information and distributed cooperative decision-making models. The paper presents a mechanism allowing a distributed regulation of the right-of-way of the vehicles at an intersection. The decision-making relies on an automati...

  4. Improved Disturbance Observer (DOB) Based Advanced Feedback Control for Optimal Operation of a Mineral Grinding Process%Improved Disturbance Observer (DOB) Based Advanced Feedback Control for Optimal Operation of a Mineral Grinding Process

    Institute of Scientific and Technical Information of China (English)

    周平; 向波; 柴天佑

    2012-01-01

    Advanced feedback control for optimal operation of mineral grinding process is usually based on the model predictive control (MPC) dynamic optimization. Since the MPC does not handle disturbances directly by controller design, it cannot achieve satisfactory effects in controlling complex grinding processes in the presence of strong disturbances and large uncertainties. In this paper, an improved disturbance observer (DOB) based MPC advanced feedback control is proposed to control the multivariable grinding operation. The improved DOB is based on the optimal achievable H 2 performance and can deal with disturbance observation for the nonminimum-phase delay systems. In this DOB-MPC advanced feedback control, the higher-level optimizer computes the optimal operation points by maximize the profit function and passes them to the MPC level. The MPC acts as a presetting controller and is employed to generate proper pre-setpoint for the lower-level basic feedback control system. The DOB acts as a compensator and improves the operation performance by dynamically compensating the setpoints for the basic control system according to the observed various disturbances and plant uncertainties. Several simulations are performed to demonstrate the proposed control method for grinding process operation.

  5. Traffic at the edge of chaos

    Energy Technology Data Exchange (ETDEWEB)

    Nagel, K. [Los Alamos National Lab., NM (United States)]|[Santa Fe Inst., Santa Fe, NM (United States)]|[Koeln Univ. (Germany). Zentrum fuer Paralleles Rechnen; Rasmussen, S. [Los Alamos National Lab., NM (United States)]|[Santa Fe Inst., Santa Fe, NM (United States)

    1994-09-01

    We use a very simple description of human driving behavior to simulate traffic. The regime of maximum vehicle flow in a closed system shows near-critical behavior, and as a result a sharp decrease of the predictability of travel time. Since Advanced Traffic Management Systems (ATMSs) tend to drive larger parts of the transportation system towards this regime of maximum flow, we argue that in consequence the traffic system as a whole will be driven closer to criticality, thus making predictions much harder. A simulation of a simplified transportation network supports our argument.

  6. Prediction feedback in intelligent traffic systems

    CERN Document Server

    Chuan-Fei, Dong; Guan-Wen, Wang; Xiao-Yan, Sun; Bing-Hong, Wang

    2009-01-01

    The optimal information feedback has a significant effect on many socioeconomic systems like stock market and traffic systems aiming to make full use of resources. In this paper, we studied dynamics of traffic flow with real-time information provided and the influence of a feedback strategy named prediction feedback strategy is introduced, based on a two-route scenario in which dynamic information can be generated and displayed on the board to guide road users to make a choice. Our model incorporates the effects of adaptability into the cellular automaton models of traffic flow and simulation results adopting this optimal information feedback strategy have demonstrated high efficiency in controlling spatial distribution of traffic patterns compared with the other three information feedback strategies, i.e., vehicle number and flux.

  7. Traffic Flow Theory

    OpenAIRE

    Maerivoet, Sven; De Moor, Bart

    2005-01-01

    The scientific field of traffic engineering encompasses a rich set of mathematical techniques, as well as researchers with entirely different backgrounds. This paper provides an overview of what is currently the state-of-the-art with respect to traffic flow theory. Starting with a brief history, we introduce the microscopic and macroscopic characteristics of vehicular traffic flows. Moving on, we review some performance indicators that allow us to assess the quality of traffic operations. A f...

  8. International Workshop on Traffic and Granular Flow

    CERN Document Server

    Herrmann, Hans; Schreckenberg, Michael; Wolf, Dietrich; Social, Traffic and Granular Dynamics

    2000-01-01

    "Are there common phenomena and laws in the dynamic behavior of granular materials, traffic, and socio-economic systems?" The answers given at the international workshop "Traffic and Granular Flow '99" are presented in this volume. From a physical standpoint, all these systems can be treated as (self)-driven many-particle systems with strong fluctuations, showing multistability, phase transitions, non-linear waves, etc. The great interest in these systems is due to several unexpected new discoveries and their practical relevance for solving some fundamental problems of today's societies. This includes intelligent measures for traffic flow optimization and methods from "econophysics" for stabilizing (stock) markets.

  9. Delay of Vehicle Motion in Traffic Dynamics

    CERN Document Server

    Bando, M; Nakanishi, K; Nakayama, A; Bando, Masako; Hasebe, Katsuya; Nakanishi, Ken; Nakayama, Akihiro

    1996-01-01

    We demonstrate that in Optimal Velocity Model (OVM) delay times of vehicles coming from the dynamical equation of motion of OVM almost explain the order of delay times observed in actual traffic flows without introducing explicit delay times. Delay times in various cases are estimated: the case of a leader vehicle and its follower, a queue of vehicles controlled by traffic lights and many-vehicle case of highway traffic flow. The remarkable result is that in most of the situation for which we can make a reasonable definition of a delay time, the obtained delay time is of order 1 second.

  10. Optimizing radiation dose by using advanced modelled iterative reconstruction in high-pitch coronary CT angiography

    International Nuclear Information System (INIS)

    To evaluate the potential of advanced modeled iterative reconstruction (ADMIRE) for optimizing radiation dose of high-pitch coronary CT angiography (CCTA). High-pitch 192-slice dual-source CCTA was performed in 25 patients (group 1) according to standard settings (ref. 100 kVp, ref. 270 mAs/rot). Images were reconstructed with filtered back projection (FBP) and ADMIRE (strength levels 1-5). In another 25 patients (group 2), high-pitch CCTA protocol parameters were adapted according to results from group 1 (ref. 160 mAs/rot), and images were reconstructed with ADMIRE level 4. In ten patients of group 1, vessel sharpness using full width at half maximum (FWHM) analysis was determined. Image quality was assessed by two independent, blinded readers. Interobserver agreements for attenuation and noise were excellent (r = 0.88/0.85, p < 0.01). In group 1, ADMIRE level 4 images were most often selected (84 %, 21/25) as preferred data set; at this level noise reduction was 40 % compared to FBP. Vessel borders showed increasing sharpness (FWHM) at increasing ADMIRE levels (p < 0.05). Image quality in group 2 was similar to that of group 1 at ADMIRE levels 2-3. Radiation dose in group 2 (0.3 ± 0.1 mSv) was significantly lower than in group 1 (0.5 ± 0.3 mSv; p < 0.05). In a selected population, ADMIRE can be used for optimizing high-pitch CCTA to an effective dose of 0.3 mSv. (orig.)

  11. Statistically Optimal Approximations of Astronomical Signals: Implications to Classification and Advanced Study of Variable Stars

    Science.gov (United States)

    Andronov, I. L.; Chinarova, L. L.; Kudashkina, L. S.; Marsakova, V. I.; Tkachenko, M. G.

    2016-06-01

    We have elaborated a set of new algorithms and programs for advanced time series analysis of (generally) multi-component multi-channel observations with irregularly spaced times of observations, which is a common case for large photometric surveys. Previous self-review on these methods for periodogram, scalegram, wavelet, autocorrelation analysis as well as on "running" or "sub-interval" local approximations were self-reviewed in (2003ASPC..292..391A). For an approximation of the phase light curves of nearly-periodic pulsating stars, we use a Trigonometric Polynomial (TP) fit of the statistically optimal degree and initial period improvement using differential corrections (1994OAP.....7...49A). For the determination of parameters of "characteristic points" (minima, maxima, crossings of some constant value etc.) we use a set of methods self-reviewed in 2005ASPC..335...37A, Results of the analysis of the catalogs compiled using these programs are presented in 2014AASP....4....3A. For more complicated signals, we use "phenomenological approximations" with "special shapes" based on functions defined on sub-intervals rather on the complete interval. E. g. for the Algol-type stars we developed the NAV ("New Algol Variable") algorithm (2012Ap.....55..536A, 2012arXiv1212.6707A, 2015JASS...32..127A), which was compared to common methods of Trigonometric Polynomial Fit (TP) or local Algebraic Polynomial (A) fit of a fixed or (alternately) statistically optimal degree. The method allows determine the minimal set of parameters required for the "General Catalogue of Variable Stars", as well as an extended set of phenomenological and astrophysical parameters which may be used for the classification. Totally more that 1900 variable stars were studied in our group using these methods in a frame of the "Inter-Longitude Astronomy" campaign (2010OAP....23....8A) and the "Ukrainian Virtual Observatory" project (2012KPCB...28...85V).

  12. Optimizing radiation dose by using advanced modelled iterative reconstruction in high-pitch coronary CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    Gordic, Sonja; Husarik, Daniela B.; Alkadhi, Hatem [University Hospital Zurich, University of Zurich, Institute of Diagnostic and Interventional Radiology, Zurich (Switzerland); Desbiolles, Lotus; Leschka, Sebastian [University Hospital Zurich, University of Zurich, Institute of Diagnostic and Interventional Radiology, Zurich (Switzerland); Kantonsspital, Divison of Radiology and Nuclear Medicine, St. Gallen (Switzerland); Sedlmair, Martin; Schmidt, Bernhard [Siemens Healthcare, Computed Tomography Division, Forchheim (Germany); Manka, Robert [University Hospital Zurich, University of Zurich, Institute of Diagnostic and Interventional Radiology, Zurich (Switzerland); University Hospital Zurich, University of Zurich, Clinic of Cardiology, Zurich (Switzerland); University and ETH Zurich, Institute for Biomedical Engineering, Zurich (Switzerland); Plass, Andre; Maisano, Francesco [University Hospital Zurich, University of Zurich, Clinic for Cardiovascular Surgery, Zurich (Switzerland); Wildermuth, Simon [Kantonsspital, Divison of Radiology and Nuclear Medicine, St. Gallen (Switzerland)

    2016-02-15

    To evaluate the potential of advanced modeled iterative reconstruction (ADMIRE) for optimizing radiation dose of high-pitch coronary CT angiography (CCTA). High-pitch 192-slice dual-source CCTA was performed in 25 patients (group 1) according to standard settings (ref. 100 kVp, ref. 270 mAs/rot). Images were reconstructed with filtered back projection (FBP) and ADMIRE (strength levels 1-5). In another 25 patients (group 2), high-pitch CCTA protocol parameters were adapted according to results from group 1 (ref. 160 mAs/rot), and images were reconstructed with ADMIRE level 4. In ten patients of group 1, vessel sharpness using full width at half maximum (FWHM) analysis was determined. Image quality was assessed by two independent, blinded readers. Interobserver agreements for attenuation and noise were excellent (r = 0.88/0.85, p < 0.01). In group 1, ADMIRE level 4 images were most often selected (84 %, 21/25) as preferred data set; at this level noise reduction was 40 % compared to FBP. Vessel borders showed increasing sharpness (FWHM) at increasing ADMIRE levels (p < 0.05). Image quality in group 2 was similar to that of group 1 at ADMIRE levels 2-3. Radiation dose in group 2 (0.3 ± 0.1 mSv) was significantly lower than in group 1 (0.5 ± 0.3 mSv; p < 0.05). In a selected population, ADMIRE can be used for optimizing high-pitch CCTA to an effective dose of 0.3 mSv. (orig.)

  13. Green Traffic Engineering for Future Core Networks

    OpenAIRE

    Athanasiou, George

    2012-01-01

    An important goal towards the design of Future Networks is to achieve the best ratio of performance to energy consumption and at the same time assure manageability. This paper presents a general problem formulation for Energy-Aware Traffic Engineering and proposes a distributed, heuristic Energy-Aware Traffic Engineering scheme (ETE) that provides load balancing and energy-awareness in accordance with the operator's needs. Simulation results of ETE compared to the optimal network performance ...

  14. Effects of Bottlenecks in Vehicle Traffic

    CERN Document Server

    Yamamoto, S; Tadaki, S; Yamamoto, Syohei; Hieida, Yasuhiro; Tadaki, Shin-ichi

    2006-01-01

    Traffic congestion is usually observed at the upper streams of bottlenecks like tunnels. Congestion appears as stop-and-go waves and high density uniform flow. We perform simulations of traffic flow with a bottleneck using the coupled map optimal velocity model. The bottleneck is expressed as a road segment with speed reduction. The emergence of stop-and-go waves depends on the speed reduction in the bottleneck. A phenomenological theory of bottleneck effects is constructed.

  15. Effects of Bottlenecks on Vehicle Traffic

    OpenAIRE

    Yamamoto, Syohei; Hieida, Yasuhiro; Tadaki, Shin-ichi

    2006-01-01

    Traffic congestion is usually observed at the upper streams of bottlenecks such as tunnels. Congestion appears as stop-and-go waves and high density uniform flow. We perform simulations of traffic flow with a bottleneck using the coupled map optimal velocity model. The bottleneck is expressed as a road segment with speed reduction. The speed reduction in the bottleneck controls the emergence of stop-and-go waves. A phenomenological theory of bottleneck effects is constructed.

  16. Traffic Flow Estimates.

    Science.gov (United States)

    Hart, Vincent G.

    1981-01-01

    Two examples are given of ways traffic engineers estimate traffic flow. The first, Floating Car Method, involves some basic ideas and the notion of relative velocity. The second, Maximum Traffic Flow, is viewed to involve simple applications of calculus. The material provides insight into specialized applications of mathematics. (MP)

  17. Optimal design of advanced distillation configuration for enhanced energy efficiency of waste solvent recovery process in semiconductor industry

    International Nuclear Information System (INIS)

    Highlights: • Thermally coupled distillation process is proposed for waste solvent recovery. • A systematic optimization procedure is used to optimize distillation columns. • Response surface methodology is applied to optimal design of distillation column. • Proposed advanced distillation allows energy efficient waste solvent recovery. - Abstract: The semiconductor industry is one of the largest industries in the world. On the other hand, the huge amount of solvent used in the industry results in high production cost and potential environmental damage because most of the valuable chemicals discharged from the process are incinerated at high temperatures. A distillation process is used to recover waste solvent, reduce the production-related costs and protect the environment from the semiconductor industrial waste. Therefore, in this study, a distillation process was used to recover the valuable chemicals from semiconductor industry discharge, which otherwise would have been lost to the environment. The conventional sequence of distillation columns, which was optimized using the Box and sequential quadratic programming method for minimum energy objectives, was used. The energy demands of a distillation problem may have a substantial influence on the profitability of a process. A thermally coupled distillation and heat pump-assisted distillation sequence was implemented to further improve the distillation performance. Finally, a comparison was made between the conventional and advanced distillation sequences, and the optimal conditions for enhancing recovery were determined. The proposed advanced distillation configuration achieved a significant energy saving of 40.5% compared to the conventional column sequence

  18. Optimal pharmacotherapeutic strategies for elderly patients with advanced non-small cell lung cancer.

    Science.gov (United States)

    Quoix, Elisabeth

    2011-11-01

    Increases in both life expectancy and cancer incidence with age result in a significant rise in lung cancer rates among elderly patients, with a median age at diagnosis of between 63 and 70 years. However, elderly patients are under-represented in clinical trials and generally receive suboptimal treatment, mainly because of fears about increased toxicity of chemotherapy. Indeed, physiological modification of renal and haematopoietic functions with age together with co-morbidity and associated polypharmacy may alter the metabolism of chemotherapy drugs, resulting in greater toxicity. Moreover, performance status (PS), the main prognostic factor in younger patients, does not correlate well with geriatric indexes such as activities of daily living, cognition and physical performance, and comprehensive geriatric assessment is important in elderly patients. Until 2010, based on the small number of clinical trials designed for elderly patients, monotherapy was the recommended treatment for those with advanced non-small cell lung cancer (NSCLC), whereas for fit younger patients, a platinum-based doublet was and continues to be the recommended first-line therapy. However, at the plenary session of the 2010 Annual Meeting of the American Society of Clinical Oncology, results were presented from a randomized controlled trial conducted by the French Intergroup of Thoracic Oncology that demonstrated that in PS 0-2 patients aged≥70 years with advanced NSCLC, monthly carboplatin with weekly paclitaxel resulted in significantly longer survival than single-agent therapy (vinorelbine or gemcitabine). It should be noted that even in a priori unfavourable prognostic subgroups (patients with a PS score of 2, those aged>80 years or those with an activities of daily living scale score of nihilism in the treatment of elderly patients with advanced NSCLC. Such patients should be evaluated carefully by geriatric indexes and, if they have a PS score of 0-2, may be treated with platinum

  19. Recent Advances in Organic Photovoltaics: Device Structure and Optical Engineering Optimization on the Nanoscale.

    Science.gov (United States)

    Luo, Guoping; Ren, Xingang; Zhang, Su; Wu, Hongbin; Choy, Wallace C H; He, Zhicai; Cao, Yong

    2016-03-01

    Organic photovoltaic (OPV) devices, which can directly convert absorbed sunlight to electricity, are stacked thin films of tens to hundreds of nanometers. They have emerged as a promising candidate for affordable, clean, and renewable energy. In the past few years, a rapid increase has been seen in the power conversion efficiency of OPV devices toward 10% and above, through comprehensive optimizations via novel photoactive donor and acceptor materials, control of thin-film morphology on the nanoscale, device structure developments, and interfacial and optical engineering. The intrinsic problems of short exciton diffusion length and low carrier mobility in organic semiconductors creates a challenge for OPV designs for achieving optically thick and electrically thin device structures to achieve sufficient light absorption and efficient electron/hole extraction. Recent advances in the field of OPV devices are reviewed, with a focus on the progress in device architecture and optical engineering approaches that lead to improved electrical and optical characteristics in OPV devices. Successful strategies are highlighted for light wave distribution, modulation, and absorption promotion inside the active layer of OPV devices by incorporating periodic nanopatterns/nanostructures or incorporating metallic nanomaterials and nanostructures. PMID:26856789

  20. 基于云平台的交通视频检测数据优化研究%Data Optimization of Traffic Video Vehicle Detector Based on Cloud Platform

    Institute of Scientific and Technical Information of China (English)

    程学庆; 刘星文; 李建海; 蒲云

    2015-01-01

    交通视频检测技术在智能交通领域应用广泛,成为当前交通信息采集的主要手段。但在恶劣天气条件下,视频车辆检测器采集的交通数据误差较大,难以准确反映路面实际状况。为解决此问题,本文提出基于不同气象能见度等级构建k型BP网络,对气象能见度低于10 km时的原始交通数据作预处理优化。分析了云计算在交通信息处理方面的优势,基于云计算平台实现了该模型的构建与推广。最后以成都绕城高速七里沟大桥定点观测得到的数据做样本进行实例分析,对比了该模型方法与传统处理方法的数据处理效果,得出了本文方法较传统方法先进的结论。%Traffic video detection technology is widely used in ITS and becomes the main form of transportation information collection. But in bad weather condition, the traffic data deviation is so large that it’s difficult to accurately reflect the traffic situation. To solve this problem,k -type BP neural network model is established based on different meteorological visibility level, then preprocess the data which collected in the meteorological visibility level below 10 km. It also analyzes the advantages of cloud computing in traffic information processing, realizes the construction and promotion of the model based on cloud computing platform. The superiority of the new model compared with the traditional method is validated by an example. Finally, an example is analyzed based on observatory date of Chengdu beltway Qiligou Bridge, compare the effectiveness of the proposed method and the traditional processing methods. The conclude shows that the proposed method is more advanced than the conventional methods.

  1. Agent Base Network Traffic Monitoring

    Directory of Open Access Journals (Sweden)

    MONIKA JOSHI, CHIRAG GOHEL

    2013-05-01

    Full Text Available Raspberry Pi the credit-card-sized single board computer device which adopts a high performance embedded microprocessor and an embedded real-time Linux operating system, which hangs the characteristics of miniaturization, digitalization and network together well. It has virtues of low cost, small volume and flexible networking, etc, because of embedded technology adoption. Network administrators need to see what’s going on with their network. They need to know what the traffic on their network is comprised of, who's using the bandwidth, and how their infrastructure is handling the load. Fortunately, Linux runs a wide variety of free, open source network monitoring and traffic analysis applications that can give net administrator this type of insight. So this paper focuses on how to deploy network monitoring tool within this device which monitors the network traffic within LAN using the tool ntop. Ntop is a simple, free, portable traffic measurement and monitoring tool, which supports various management activities, including network optimization and to plan, and detection of network security violations.

  2. 基于团树传播的强化学习交通信号协调控制的研究%Clique-Tree Propagation Based on Learning Algorithm to Optimize Network Wide Traffic Control

    Institute of Scientific and Technical Information of China (English)

    吴冬; 康琦; 张轮; 汪镭

    2016-01-01

    针对当前城市交通信号控制效率低下,致使车辆在道路交叉口等待时间较长,停车次数较多等问题,提出了一种新型的基于团树传播算法的强化学习控制方法来协调控制网络级交通.分别重点介绍强化学习算法与以联合树算法为代表的团树传播算法如何与交通控制相结合以及联合树算法是如何实现联合动作推理的.选取24个交叉口组成的路网为研究对象,在交通仿真软件VISSIM中进行仿真,软件可读取当前环境的状态,选取车辆的平均延误和平均停车次数作为性能指标,同时,分别与相邻路口简单协调的强化学习控制算法、无学习的LQF算法控制效果进行比较.%On account of the inefficiency of current traffic signal control system,resulting in long waits and more stops for most vehicles at the road intersections, this paper propose a novel reinforcement learning algorithm based on clique-tree propagation to optimize network wide traffic control.We focuses on how reinforcement learning and junction tree algorithm ,a typical Clique tree propagation algorithm,combined with traffic signal control and how the Junction tree algorithm achieve joint action reasoning. The algorithm is testd with a network containing 24 intersections,simulated in VISSIM, a traffic simulation software which can read the current state of the environment,choose the average vehicle delay and average number of stops as performance indicator.We also compare with simple reinforcement learning control algorithm which intersections coordinated with neighborhood and LQF algorithm.

  3. Traffic Square Management System

    OpenAIRE

    Sujata V. Padole

    2013-01-01

    If the traffic is more on one side and less on other side so there all way a waste of time and fuel on the traffic signal. Which is serious problem now day so there an need to have an intelligent traffic system which can detect the amount of traffic and make the change accordingly by using sensor and tranducer. Also by using motion detection camera at the lane we can find out the vehicle owner who break the traffic rules at the signal.

  4. Modelling the Traffic System

    Directory of Open Access Journals (Sweden)

    Važan Pavel

    2014-12-01

    Full Text Available The paper presents the simulation study results of the traffic system in the city of Hlohovec. The authors describe the process of building the model in Witness 2013c simulator. The individual entities of simulation model are explained in details, as the Witness simulator is primarily suitable for manufacture or service simulation and not for traffic system simulation. The goal of this paper is to analyse the traffic system and to suggest the changes for improving the traffic in the city of Hlohovec. All proposed measures will bring about 20% improvement of traffic when compared to the current state.

  5. Search Engine Optimization

    CERN Document Server

    Davis, Harold

    2006-01-01

    SEO--short for Search Engine Optimization--is the art, craft, and science of driving web traffic to web sites. Web traffic is food, drink, and oxygen--in short, life itself--to any web-based business. Whether your web site depends on broad, general traffic, or high-quality, targeted traffic, this PDF has the tools and information you need to draw more traffic to your site. You'll learn how to effectively use PageRank (and Google itself); how to get listed, get links, and get syndicated; and much more. The field of SEO is expanding into all the possible ways of promoting web traffic. This

  6. CONTROLLING TRAFFIC FLOW IN MULTILANE-ISOLATED INTERSECTION USING ANFIS APPROACH TECHNIQUES

    OpenAIRE

    G. R. LAI; A. CHE SOH; H. MD. SARKAN; R. Z. ABDUL RAHMAN; Hassan, M. K.

    2015-01-01

    Many controllers have applied the Adaptive Neural-Fuzzy Inference System (ANFIS) concept for optimizing the controller performance. However, there are less traffic signal controllers developed using the ANFIS concept. ANFIS traffic signal controller with its fuzzy rule base and its ability to learn from a set of sample data could improve the performance of Existing traffic signal controlling system to reduce traffic congestions at most of the busy traffic intersections in city such as Kuala L...

  7. Optimization Design of Traffic Light Control Program Based PLC%基于PLC的交通灯控制程序优化设计

    Institute of Scientific and Technical Information of China (English)

    刘爱云

    2012-01-01

    Based on Siemens S7-200 PLC instruction system for crossroads traffic lights control program design, my paper gives three different design methods which use of bit logic instruction, sequential control instruction and compare instruction. By comparing, the method which using compare instruction is more simple and easy to understand.%文章利用西门子S7 -200PLC指令系统进行十字路口交通灯控制的程序设计,给出利用位逻辑指令、顺控指令、比较指令三种不同的设计思路,通过对比,利用比较指令实现的程序,更加简单和容易理解.

  8. Evolutionary optimization and game strategies for advanced multi-disciplinary design applications to aeronautics and UAV design

    CERN Document Server

    Periaux, Jacques; Lee, Dong Seop Chris

    2015-01-01

    Many complex aeronautical design problems can be formulated with efficient multi-objective evolutionary optimization methods and game strategies. This book describes the role of advanced innovative evolution tools in the solution, or the set of solutions of single or multi disciplinary optimization. These tools use the concept of multi-population, asynchronous parallelization and hierarchical topology which allows different models including precise, intermediate and approximate models with each node belonging to the different hierarchical layer handled by a different Evolutionary Algorithm. The efficiency of evolutionary algorithms for both single and multi-objective optimization problems are significantly improved by the coupling of EAs with games and in particular by a new dynamic methodology named “Hybridized Nash-Pareto games”. Multi objective Optimization techniques and robust design problems taking into account uncertainties are introduced and explained in detail. Several applications dealing with c...

  9. Real-time optical path control method that utilizes multiple support vector machines for traffic prediction

    Science.gov (United States)

    Kawase, Hiroshi; Mori, Yojiro; Hasegawa, Hiroshi; Sato, Ken-ichi

    2016-02-01

    An effective solution to the continuous Internet traffic expansion is to offload traffic to lower layers such as the L2 or L1 optical layers. One possible approach is to introduce dynamic optical path operations such as adaptive establishment/tear down according to traffic variation. Path operations cannot be done instantaneously; hence, traffic prediction is essential. Conventional prediction techniques need optimal parameter values to be determined in advance by averaging long-term variations from the past. However, this does not allow adaptation to the ever-changing short-term variations expected to be common in future networks. In this paper, we propose a real-time optical path control method based on a machinelearning technique involving support vector machines (SVMs). A SVM learns the most recent traffic characteristics, and so enables better adaptation to temporal traffic variations than conventional techniques. The difficulty lies in determining how to minimize the time gap between optical path operation and buffer management at the originating points of those paths. The gap makes the required learning data set enormous and the learning process costly. To resolve the problem, we propose the adoption of multiple SVMs running in parallel, trained with non-overlapping subsets of the original data set. The maximum value of the outputs of these SVMs will be the estimated number of necessary paths. Numerical experiments prove that our proposed method outperforms a conventional prediction method, the autoregressive moving average method with optimal parameter values determined by Akaike's information criterion, and reduces the packet-loss ratio by up to 98%.

  10. Implications of traffic characteristics on interdomain traffic engineering

    OpenAIRE

    Uhlig, Steve

    2004-01-01

    This thesis discusses the implications of the traffic characteristics on interdomain traffic engineering with BGP. We first provide an overview of the interdomain traffic control problem. Then, we present results concerning the characteristics of the interdomain traffic, based on the analysis of real traffic traces gathered from non-transit ASes. We discuss the implications of the topological properties of the traffic on interdomain traffic engineering. Based on this knowledge of the...

  11. Proposal and Implementation of MPLS Fuzzy Traffic Monitor

    Directory of Open Access Journals (Sweden)

    Anju Bhandari

    2016-01-01

    Full Text Available Multiprotocol Label Switched Networks need highly intelligent controls to manage high volume traffic due to issues of traffic congestion and best path selection. The work demonstrated in this paper shows results from simulations for building optimal fuzzy based algorithm for traffic splitting and congestion avoidance. The design and implementation of Fuzzy based software defined networking is illustrated by introducing the Fuzzy Traffic Monitor in an ingress node. Finally, it displays improvements in the terms of mean delay (42.0% and mean loss rate (2.4% for Video Traffic. Then, the resu1t shows an improvement in the terms of mean delay (5.4% and mean loss rate (3.4% for Data Traffic and an improvement in the terms of mean delay(44.9% and mean loss rate(4.1% for Voice Traffic as compared to default MPLS implementation.

  12. A knowledge-based system for controlling automobile traffic

    Science.gov (United States)

    Maravas, Alexander; Stengel, Robert F.

    1994-01-01

    Transportation network capacity variations arising from accidents, roadway maintenance activity, and special events as well as fluctuations in commuters' travel demands complicate traffic management. Artificial intelligence concepts and expert systems can be useful in framing policies for incident detection, congestion anticipation, and optimal traffic management. This paper examines the applicability of intelligent route guidance and control as decision aids for traffic management. Basic requirements for managing traffic are reviewed, concepts for studying traffic flow are introduced, and mathematical models for modeling traffic flow are examined. Measures for quantifying transportation network performance levels are chosen, and surveillance and control strategies are evaluated. It can be concluded that automated decision support holds great promise for aiding the efficient flow of automobile traffic over limited-access roadways, bridges, and tunnels.

  13. Advanced Modeling of Cold Crucible Induction Melting for Process Control and Optimization

    Energy Technology Data Exchange (ETDEWEB)

    J. A. Roach; D. B. Lopukh; A. P. Martynov; B. S. Polevodov; S. I. Chepluk

    2008-02-01

    The Idaho National Laboratory (INL) and the St. Petersburg Electrotechnical University “LETI” (ETU) have collaborated on development and validation of an advanced numerical model of the cold crucible induction melting (CCIM) process. This work was conducted in support of the Department of Energy (DOE) Office of Environmental Management Technology and Engineering (EM-20) International Program. The model predicts quasi-steady state temperature distributions, convection cell configurations, and flow field velocities for a fully established melt of low conductivity non-magnetic materials at high frequency operations. The INL/ETU ANSYS© finite element model is unique in that it has been developed specifically for processing borosilicate glass (BSG) and other glass melts. Specifically, it accounts for the temperature dependency of key material properties, some of which change by orders of magnitude within the temperature ranges experienced (temperature differences of 500oC are common) in CCIM processing of glass, including density, viscosity, thermal conductivity, specific heat, and electrical resistivity. These values, and their responses to temperature changes, are keys to understanding the melt characteristics. Because the model has been validated, it provides the capability to conduct parametric studies to understand operational sensitivities and geometry effects. Additionally, the model can be used to indirectly determine difficult to measure material properties at higher temperatures such as resistivity, thermal conductivity and emissivity. The model can also be used to optimize system design and to predict operational behavior for specific materials and system configurations, allowing automated feedback control. This becomes particularly important when designing melter systems for full-scale industrial applications.

  14. DOE Project: Optimization of Advanced Diesel Engine Combustion Strategies "University Research in Advanced Combustion and Emissions Control" Office of FreedomCAR and Vehicle Technologies Program

    Energy Technology Data Exchange (ETDEWEB)

    Reitz, Rolf; Foster, D.; Ghandhi, J.; Rothamer, D.; Rutland, C.; Sanders, S.; Trujillo, M.

    2012-10-26

    The goal of the present technology development was to increase the efficiency of internal combustion engines while minimizing the energy penalty of meeting emissions regulations. This objective was achieved through experimentation and the development of advanced combustion regimes and emission control strategies, coupled with advanced petroleum and non-petroleum fuel formulations. To meet the goals of the project, it was necessary to improve the efficiency of expansion work extraction, and this required optimized combustion phasing and minimized in-cylinder heat transfer losses. To minimize fuel used for diesel particulate filter (DPF) regeneration, soot emissions were also minimized. Because of the complex nature of optimizing production engines for real-world variations in fuels, temperatures and pressures, the project applied high-fidelity computing and high-resolution engine experiments synergistically to create and apply advanced tools (i.e., fast, accurate predictive models) developed for low-emission, fuel-efficient engine designs. The companion experiments were conducted using representative single- and multi-cylinder automotive and truck diesel engines.

  15. Software for Simulating Air Traffic

    Science.gov (United States)

    Sridhar, Banavar; Bilimoria, Karl; Grabbe, Shon; Chatterji, Gano; Sheth, Kapil; Mulfinger, Daniel

    2006-01-01

    Future Air Traffic Management Concepts Evaluation Tool (FACET) is a system of software for performing computational simulations for evaluating advanced concepts of advanced air-traffic management. FACET includes a program that generates a graphical user interface plus programs and databases that implement computational models of weather, airspace, airports, navigation aids, aircraft performance, and aircraft trajectories. Examples of concepts studied by use of FACET include aircraft self-separation for free flight; prediction of air-traffic-controller workload; decision support for direct routing; integration of spacecraft-launch operations into the U.S. national airspace system; and traffic- flow-management using rerouting, metering, and ground delays. Aircraft can be modeled as flying along either flight-plan routes or great-circle routes as they climb, cruise, and descend according to their individual performance models. The FACET software is modular and is written in the Java and C programming languages. The architecture of FACET strikes a balance between flexibility and fidelity; as a consequence, FACET can be used to model systemwide airspace operations over the contiguous U.S., involving as many as 10,000 aircraft, all on a single desktop or laptop computer running any of a variety of operating systems. Two notable applications of FACET include: (1) reroute conformance monitoring algorithms that have been implemented in one of the Federal Aviation Administration s nationally deployed, real-time, operational systems; and (2) the licensing and integration of FACET with the commercially available Flight Explorer, which is an Internet- based, real-time flight-tracking system.

  16. Intelligent City Traffic Management and Public Transportation System

    OpenAIRE

    Mulay, Snehal; Dhekne, Chinmay; Bapat, Rucha; Budukh, Tanmay; Gadgil, Soham

    2013-01-01

    Intelligent Transportation System in case of cities is controlling traffic congestion and regulating the traffic flow. This paper presents three modules that will help in managing city traffic issues and ultimately gives advanced development in transportation system. First module, Congestion Detection and Management will provide user real time information about congestion on the road towards his destination, Second module, Intelligent Public Transport System will provide user real time public...

  17. Traffic Convexity Aware Cellular Networks: A Vehicular Heavy User Perspective

    OpenAIRE

    Shim, Taehyoung; Park, Jihong; Ko, Seung-Woo; Kim, Seong-Lyun; Lee, Beom Hee; Choi, Jin Gu

    2015-01-01

    Rampant mobile traffic increase in modern cellular networks is mostly caused by large-sized multimedia contents. Recent advancements in smart devices as well as radio access technologies promote the consumption of bulky content, even for people in moving vehicles, referred to as vehicular heavy users. In this article the emergence of vehicular heavy user traffic is observed by field experiments conducted in 2012 and 2015 in Seoul, Korea. The experiments reveal that such traffic is becoming do...

  18. Contribution to the optimization of 4G mobile communications by means of advanced carrier aggregation strategies

    OpenAIRE

    Lema Rosas, María Ángel

    2015-01-01

    Mobile broadband subscriptions and data traffic have increasingly grown in the past years with the deployment of the 3G and 4G technologies and the massive use of mobile devices. In this sense, LTE-A has been presented as the next step in wireless communications where higher data rates are targeted and fully packet switched services are held. The ultimate goal of 4G and the forthcoming 5G technology is to increase the Quality of Experience (QoE) of users. In this context, several challenges o...

  19. Decentralized Traffic Management Strategies for Sensor-Enabled Cars

    OpenAIRE

    Wang, Ziyuan; Kulik, Lars; Ramamohanarao, Kotagiri

    2009-01-01

    Traffic Congestions and accidents are major concerns in today's transportation systems. This thesis investigates how to optimize traffic flow on highways, in particular for merging situations such as intersections where a ramp leads onto the highway. In our work, cars are equipped with sensors that can detect distance to neighboring cars, and communicate their velocity and acceleration readings with one another. Sensor-enabled cars can locally exchange sensed information about the traffic and...

  20. A new traffic allocation algorithm in Ad hoc networks

    Institute of Scientific and Technical Information of China (English)

    LI Xin; MIAO Jian-song; SUN Dan-dan; ZHOU Li-gang; DING Wei

    2006-01-01

    A dynamic traffic distribution algorithm based on the minimization product of packet delay and packet energy consumption is proposed. The algorithm is based on packet delay and energy consumption in allocating traffic, which can optimize the network performance. Simulation demonstrated that the algorithm could dynamically adjust to the traffic distribution between paths, which can minimize the product of packet delay and energy consumption in mobile Ad hoc networks.

  1. An Area-Aggregated Dynamic Traffic Simulation Model

    OpenAIRE

    Knoop, V.L.; Hoogendoorn, S. P.

    2015-01-01

    Microscopic and macroscopic dynamic traffic models not fast enough to run in an optimization loop to coordinate traffic measures over areas of twice a trip length (50x50 km). Moreover, in strategic planning there are models with a spatial high level of detail, but lacking the features of traffic dynamics. This paper introduces the Network Transmission Model (NTM), a model based on areas, exploiting the Macroscopic or Network Fundamental Diagram (NFD). For the first time, a full operational mo...

  2. Costs of traffic injuries

    DEFF Research Database (Denmark)

    Kruse, Marie

    2015-01-01

    OBJECTIVE: The aim of this study was to analyse the socioeconomic costs of traffic injuries in Denmark, notably the healthcare costs and the productivity costs related to traffic injuries, in a bottom-up, register-based perspective. METHOD: Traffic injury victims were identified using national...... emergency room data and police records. Victims were matched with five controls per case by means of propensity score, nearest-neighbour matching. In the cohort, consisting of the 52 526 individuals that experienced a traffic injury in 2000 and 262 630 matched controls, attributable healthcare costs were...... assessed using Danish national healthcare registers. Productivity costs were computed using duration analysis (Cox regression models). In a subanalysis, cost per severe traffic injury was computed for the 12 995 individuals that experienced a severe injury. RESULTS: The socioeconomic cost of a traffic...

  3. Trajectory Based Traffic Analysis

    DEFF Research Database (Denmark)

    Krogh, Benjamin Bjerre; Andersen, Ove; Lewis-Kelham, Edwin;

    2013-01-01

    We present the INTRA system for interactive path-based traffic analysis. The analyses are developed in collaboration with traffic researchers and provide novel insights into conditions such as congestion, travel-time, choice of route, and traffic-flow. INTRA supports interactive point-and-click a......We present the INTRA system for interactive path-based traffic analysis. The analyses are developed in collaboration with traffic researchers and provide novel insights into conditions such as congestion, travel-time, choice of route, and traffic-flow. INTRA supports interactive point......-and-click analysis, due to a novel and efficient indexing structure. With the web-site daisy.aau.dk/its/spqdemo/we will demonstrate several analyses, using a very large real-world data set consisting of 1.9 billion GPS records (1.5 million trajectories) recorded from more than 13000 vehicles, and touching most of...

  4. Internet Traffic Engineering

    OpenAIRE

    Bonaventure, Olivier; Trimintzios, Panos; Pavlou, George; Quoitin, Bruno; Azcorra, Arturo; Bagnulo, Marcelo; Fegkas, Paris; García-Martínez, Alberto; Georgatsos, Panos; Georgiadis, Leonidas; Jacquenet, Christian; Swinnen, Louis; Tandel, Sebastien; Uhlig, Steve

    2004-01-01

    Traffic engineering encompasses a set of techniques that can be used to control the flow of traffic in data networks. We discuss several of those techniques that have been developed during the last few years. Some techniques are focused on pure IP networks while others have been designed with emerging technologies for scalable Quality of Service (QoS) such as Differentiated Services and MPLS in mind. We first discuss traffic engineering techniques inside a single domain. We show that by using...

  5. Distraction in traffic.

    OpenAIRE

    2013-01-01

    Many drivers, as well as cyclists and pedestrians, are occupied with all kinds of activities that can distract their attention from traffic, like listening to music, conducting a conversation on their mobile phone, or texting. Distraction has negative effects on traffic behaviour. Most studies estimate that distraction plays a role in the occurrence of about 5-25% of the car crashes. Considering the increasing diffusion of electronic devices in traffic, portable media devices as well as advan...

  6. Traffic Signs Inventory System

    Directory of Open Access Journals (Sweden)

    J. Ružbarský

    2013-06-01

    Full Text Available The paper is focused on practical application of Cambridge Correlator. The goal is to propose a traffic signs inventory system by using excellent characteristics of correlator in the rapid optical correlation. The proposal of this inventory system includes obtaining of traffic signs to create the database either collecting the GPS coordinates. It is necessary to know the traffic signs position and also to document the entire surface route for later evaluation in offline mode.

  7. Traffic Light Options

    OpenAIRE

    Løchte, Peter

    2006-01-01

    This paper introduces, prices, and analyzes traffic light options. The traffic light option is an innovative structured OTC derivative developed independently by several London-based investment banks to suit the needs of Danish life and pension (L&P) companies, which must comply with the traffic light solvency stress test system introduced by the Danish Financial Supervisory Authority (DFSA) in June 2001. This monitoring system requires L&P companies to submit regular reports documenting the ...

  8. Network Traffic Anomaly Detection

    OpenAIRE

    Huang, Hong; Al-Azzawi, Hussein; Brani, Hajar

    2014-01-01

    This paper presents a tutorial for network anomaly detection, focusing on non-signature-based approaches. Network traffic anomalies are unusual and significant changes in the traffic of a network. Networks play an important role in today's social and economic infrastructures. The security of the network becomes crucial, and network traffic anomaly detection constitutes an important part of network security. In this paper, we present three major approaches to non-signature-based network detect...

  9. Traffic Flow Management System

    Data.gov (United States)

    Department of Transportation — TFMS is a set NAS operational tools that predict demand, identify constraints, and facilitates collaboration among NAS users to support efficient traffic flow while...

  10. Subjective safety in traffic.

    OpenAIRE

    2012-01-01

    The term ‘subjective safety in traffic’ refers to people feeling unsafe in traffic or, more generally, to anxiety regarding being unsafe in traffic for oneself and/or others. Subjective safety in traffic can lead to road users limiting their mobility and social activities, which is one of the reasons it warrants policy-related attention. However, research has shown that, at most, there is a weak link between objective and subjective safety in traffic. There are even indications that some subj...

  11. Soil, crop and emission responses to seasonal-controlled traffic in organic vegetable farming on loam soil

    NARCIS (Netherlands)

    Vermeulen, G.D.; Mosquera Losada, J.

    2009-01-01

    Some organic arable and vegetable farms in the Netherlands use cm-precise guidance of machinery to restrict wheel traffic to fixed traffic lanes and to achieve non-trafficked cropping zones with optimized soil structure in between the lanes. Contrary to controlled traffic farming (CTF) the traffic l

  12. On short-term traffic flow forecasting and its reliability

    OpenAIRE

    Abouaissa, Hassane; Fliess, Michel; Join, Cédric

    2016-01-01

    International audience Recent advances in time series, where deterministic and stochastic modelings as well as the storage and analysis of big data are useless, permit a new approach to short-term traffic flow forecasting and to its reliability, i.e., to the traffic volatility. Several convincing computer simulations, which utilize concrete data, are presented and discussed.

  13. Traffic Management for Next Generation Transport Networks

    DEFF Research Database (Denmark)

    Yu, Hao

    management functions at the edge of the network, scheduling traffic on behalf of the other nodes. The topology-based hierarchical scheduling scheme is able to provide outstanding flow isolation due to its centralized scheduling ability, which is essential for providing IPTV services. In order to reduce the...... network capacities. However, in order to provide more advanced video services than simply porting the traditional television services to the network, the service provider needs to do more than just augment the network capacity. Advanced traffic management capability is one of the relevant abilities...... slacken the steps of some network operators towards providing IPTV services. In this dissertation, the topology-based hierarchical scheduling scheme is proposed to tackle the problem addressed. The scheme simplifies the deployment process by placing an intelligent switch with centralized traffic...

  14. Modeling Road Traffic Using Service Center

    Directory of Open Access Journals (Sweden)

    HARAGOS, I.-M.

    2012-05-01

    Full Text Available Transport systems have an essential role in modern society because they facilitate access to natural resources and they stimulate trade. Current studies aimed at improving transport networks by developing new methods for optimization. Because of the increase in the global number of cars, one of the most common problems facing the transport network is congestion. By creating traffic models and simulate them, we can avoid this problem and find appropriate solutions. In this paper we propose a new method for modeling traffic. This method considers road intersections as being service centers. A service center represents a set consisting of a queue followed by one or multiple servers. This model was used to simulate real situations in an urban traffic area. Based on this simulation, we have successfully determined the optimal functioning and we have computed the performance measures.

  15. Fast Drawing of Traffic Sign Using Mobile Mapping System

    Science.gov (United States)

    Yao, Q.; Tan, B.; Huang, Y.

    2016-06-01

    Traffic sign provides road users with the specified instruction and information to enhance traffic safety. Automatic detection of traffic sign is important for navigation, autonomous driving, transportation asset management, etc. With the advance of laser and imaging sensors, Mobile Mapping System (MMS) becomes widely used in transportation agencies to map the transportation infrastructure. Although many algorithms of traffic sign detection are developed in the literature, they are still a tradeoff between the detection speed and accuracy, especially for the large-scale mobile mapping of both the rural and urban roads. This paper is motivated to efficiently survey traffic signs while mapping the road network and the roadside landscape. Inspired by the manual delineation of traffic sign, a drawing strategy is proposed to quickly approximate the boundary of traffic sign. Both the shape and color prior of the traffic sign are simultaneously involved during the drawing process. The most common speed-limit sign circle and the statistic color model of traffic sign are studied in this paper. Anchor points of traffic sign edge are located with the local maxima of color and gradient difference. Starting with the anchor points, contour of traffic sign is drawn smartly along the most significant direction of color and intensity consistency. The drawing process is also constrained by the curvature feature of the traffic sign circle. The drawing of linear growth is discarded immediately if it fails to form an arc over some steps. The Kalman filter principle is adopted to predict the temporal context of traffic sign. Based on the estimated point,we can predict and double check the traffic sign in consecutive frames.The event probability of having a traffic sign over the consecutive observations is compared with the null hypothesis of no perceptible traffic sign. The temporally salient traffic sign is then detected statistically and automatically as the rare event of having a

  16. The Traffic Light Challenge

    Science.gov (United States)

    Roman, Harry T.

    2014-01-01

    Traffic lights are an important part of the transportation infrastructure, regulating traffic flow and maintaining safety when crossing busy streets. When they go awry or become nonfunctional, a great deal of havoc and danger can be present. During power outages, the street lights go out all over the affected area. It would be good to be able to…

  17. Distraction in traffic.

    NARCIS (Netherlands)

    2013-01-01

    Many drivers, as well as cyclists and pedestrians, are occupied with all kinds of activities that can distract their attention from traffic, like listening to music, conducting a conversation on their mobile phone, or texting. Distraction has negative effects on traffic behaviour. Most studies estim

  18. Road Traffic in China

    NARCIS (Netherlands)

    Jie, L.; Van Zuylen, H.J.

    2014-01-01

    Traffic is tightly related to the social and economic development in a country. In China the development of the economy has been very fast in the past 30 years and this is still continuing. The transport infrastructure shows a similar pattern, while traffic is also rapidly growing. In urban areas th

  19. Controlled Traffic Farming

    OpenAIRE

    Controlled Traffic Farming Europe

    2011-01-01

    Metadata only record Controlled Traffic Farming (CTF) is a farming method used to reduce soil compaction, decrease inputs, and improve soil structure when coupled with reduced-till or no-till practices. This practices utilizes permanent traffic/wheel zones to limit soil compaction to a specific area. This website provides practical information on CTF, case studies, workshops, and links to additional resources.

  20. Visualization of Traffic Accidents

    Science.gov (United States)

    Wang, Jie; Shen, Yuzhong; Khattak, Asad

    2010-01-01

    Traffic accidents have tremendous impact on society. Annually approximately 6.4 million vehicle accidents are reported by police in the US and nearly half of them result in catastrophic injuries. Visualizations of traffic accidents using geographic information systems (GIS) greatly facilitate handling and analysis of traffic accidents in many aspects. Environmental Systems Research Institute (ESRI), Inc. is the world leader in GIS research and development. ArcGIS, a software package developed by ESRI, has the capabilities to display events associated with a road network, such as accident locations, and pavement quality. But when event locations related to a road network are processed, the existing algorithm used by ArcGIS does not utilize all the information related to the routes of the road network and produces erroneous visualization results of event locations. This software bug causes serious problems for applications in which accurate location information is critical for emergency responses, such as traffic accidents. This paper aims to address this problem and proposes an improved method that utilizes all relevant information of traffic accidents, namely, route number, direction, and mile post, and extracts correct event locations for accurate traffic accident visualization and analysis. The proposed method generates a new shape file for traffic accidents and displays them on top of the existing road network in ArcGIS. Visualization of traffic accidents along Hampton Roads Bridge Tunnel is included to demonstrate the effectiveness of the proposed method.

  1. Traffic Light Options

    DEFF Research Database (Denmark)

    Jørgensen, Peter Løchte

    This paper introduces, prices, and analyzes traffic light options. The traffic light option is an innovative structured OTC derivative developed independently by several London-based investment banks to suit the needs of Danish life and pension (L&P) companies, which must comply with the traffic...... light solvency stress test system introduced by the Danish Financial Supervisory Authority (DFSA) in June 2001. This monitoring system requires L&P companies to submit regular reports documenting the sensitivity of the companies' base capital to certain pre-defined market shocks - the red and yellow...... light scenarios. These stress scenarios entail drops in interest rates as well as in stock prices, and traffic light options are thus designed to pay off and preserve sufficient capital when interest rates and stock prices fall simultaneously. Sweden's FSA implemented a traffic light system in January...

  2. Traffic Light Options

    DEFF Research Database (Denmark)

    Jørgensen, Peter Løchte

    2007-01-01

    This paper introduces, prices, and analyzes traffic light options. The traffic light option is an innovative structured OTC derivative developed independently by several London-based investment banks to suit the needs of Danish life and pension (L&P) companies, which must comply with the traffic...... light solvency stress test system introduced by the Danish Financial Supervisory Authority (DFSA) in June 2001. This monitoring system requires L&P companies to submit regular reports documenting the sensitivity of the companies' base capital to certain pre-defined market shocks - the red and yellow...... light scenarios. These stress scenarios entail drops in interest rates as well as in stock prices, and traffic light options are thus designed to pay off and preserve sufficient capital when interest rates and stock prices fall simultaneously. Sweden's FSA implemented a traffic light system in January...

  3. Design and Optimization of a Composite Canard Control Surface of an Advanced Fighter Aircraft under Static Loading

    Science.gov (United States)

    Shrivastava, Sachin; Mohite, P. M.

    2015-01-01

    The minimization of weight and maximization of payload is an ever challenging design procedure for air vehicles. The present study has been carried out with an objective to redesign control surface of an advanced all-metallic fighter aircraft. In this study, the structure made up of high strength aluminum, titanium and ferrous alloys has been attempted to replace by carbon fiber composite (CFC) skin, ribs and stiffeners. This study presents an approach towards development of a methodology for optimization of first-ply failure index (FI) in unidirectional fibrous laminates using Genetic-Algorithms (GA) under quasi-static loading. The GAs, by the application of its operators like reproduction, cross-over, mutation and elitist strategy, optimize the ply-orientations in laminates so as to have minimum FI of Tsai-Wu first-ply failure criterion. The GA optimization procedure has been implemented in MATLAB and interfaced with commercial software ABAQUS using python scripting. FI calculations have been carried out in ABAQUS with user material subroutine (UMAT). The GA's application gave reasonably well-optimized ply-orientations combination at a faster convergence rate. However, the final optimized sequence of ply-orientations is obtained by tweaking the sequences given by GA's based on industrial practices and experience, whenever needed. The present study of conversion of an all metallic structure to partial CFC structure has led to 12% of weight reduction. Therefore, the approach proposed here motivates designer to use CFC with a confidence.

  4. Design and Optimization of a Composite Canard Control Surface of an Advanced Fighter Aircraft under Static Loading

    Directory of Open Access Journals (Sweden)

    Shrivastava Sachin

    2015-01-01

    Full Text Available The minimization of weight and maximization of payload is an ever challenging design procedure for air vehicles. The present study has been carried out with an objective to redesign control surface of an advanced all-metallic fighter aircraft. In this study, the structure made up of high strength aluminum, titanium and ferrous alloys has been attempted to replace by carbon fiber composite (CFC skin, ribs and stiffeners. This study presents an approach towards development of a methodology for optimization of first-ply failure index (FI in unidirectional fibrous laminates using Genetic-Algorithms (GA under quasi-static loading. The GAs, by the application of its operators like reproduction, cross-over, mutation and elitist strategy, optimize the ply-orientations in laminates so as to have minimum FI of Tsai-Wu first-ply failure criterion. The GA optimization procedure has been implemented in MATLAB and interfaced with commercial software ABAQUS using python scripting. FI calculations have been carried out in ABAQUS with user material subroutine (UMAT. The GA's application gave reasonably well-optimized ply-orientations combination at a faster convergence rate. However, the final optimized sequence of ply-orientations is obtained by tweaking the sequences given by GA's based on industrial practices and experience, whenever needed. The present study of conversion of an all metallic structure to partial CFC structure has led to 12% of weight reduction. Therefore, the approach proposed here motivates designer to use CFC with a confidence.

  5. Nonequilibrium phase separation in traffic flows

    OpenAIRE

    Hayakawa, H; Nakanishi, K.

    1997-01-01

    Traffic jam in an optimal velocity model with the backward reference function is analyzed. An analytic scaling solution is presented near the critical point of the phase separation. The validity of the solution has been confirmed from the comparison with the simulation of the model.

  6. Using Collective Intelligence to Route Internet Traffic

    OpenAIRE

    David H. Wolpert; Tumer, Kagan; Frank, Jeremy

    1999-01-01

    A COllective INtelligence (COIN) is a set of interacting reinforcement learning (RL) algorithms designed in an automated fashion so that their collective behavior optimizes a global utility function. We summarize the theory of COINs, then present experiments using that theory to design COINs to control internet traffic routing. These experiments indicate that COINs outperform all previously investigated RL-based, shortest path routing algorithms.

  7. Advanced Modeling System for Optimization of Wind Farm Layout and Wind Turbine Sizing Using a Multi-Level Extended Pattern Search Algorithm

    Energy Technology Data Exchange (ETDEWEB)

    DuPont, Bryony; Cagan, Jonathan; Moriarty, Patrick

    2016-07-01

    This paper presents a system of modeling advances that can be applied in the computational optimization of wind plants. These modeling advances include accurate cost and power modeling, partial wake interaction, and the effects of varying atmospheric stability. To validate the use of this advanced modeling system, it is employed within an Extended Pattern Search (EPS)-Multi-Agent System (MAS) optimization approach for multiple wind scenarios. The wind farm layout optimization problem involves optimizing the position and size of wind turbines such that the aerodynamic effects of upstream turbines are reduced, which increases the effective wind speed and resultant power at each turbine. The EPS-MAS optimization algorithm employs a profit objective, and an overarching search determines individual turbine positions, with a concurrent EPS-MAS determining the optimal hub height and rotor diameter for each turbine. Two wind cases are considered: (1) constant, unidirectional wind, and (2) three discrete wind speeds and varying wind directions, each of which have a probability of occurrence. Results show the advantages of applying the series of advanced models compared to previous application of an EPS with less advanced models to wind farm layout optimization, and imply best practices for computational optimization of wind farms with improved accuracy.

  8. Application of Advanced Particle Swarm Optimization Techniques to Wind-thermal Coordination

    DEFF Research Database (Denmark)

    Singh, Sri Niwas; Østergaard, Jacob; Yadagiri, J.

    wind-thermal coordination algorithm is necessary to determine the optimal proportion of wind and thermal generator capacity that can be integrated into the system. In this paper, four versions of Particle Swarm Optimization (PSO) techniques are proposed for solving wind-thermal coordination problem. A...... pseudo code based algorithm is suggested to deal with the equality constraints of the problem for accelerating the optimization process. The simulation results show that the proposed PSO methods are capable of obtaining higher quality solutions efficiently in wind-thermal coordination problems....

  9. Challenges in optimizing chemoradiation in locally advanced non small-cell lung cancers in India

    OpenAIRE

    Sushma Agrawal

    2013-01-01

    Data supporting use of concurrent chemoradiation in locally advanced lung cancers comes from clinical trials from developed countries. Applicability and outcomes of such schedules in developing countries is not widely reported. There are various challenges in delivering chemoradiation in locally advanced non small cell lung cancer in developing countries which is highlighted by an audit of patients treated with chemoradiation in our center. This article deals with the challenges in the contex...

  10. ROBOTICALLY ENHANCED ADVANCED MANUFACTURING CONCEPTS TO OPTIMIZE ENERGY, PRODUCTIVITY, AND ENVIRONMENTAL PERFORMANCE

    Energy Technology Data Exchange (ETDEWEB)

    Larry L. Keller; Joseph M. Pack; Robert V. Kolarik II

    2007-11-05

    In the first phase of the REML project, major assets were acquired for a manufacturing line for follow-on installation, capability studies and optimization. That activity has been documented in the DE-FC36-99ID13819 final report. In this the second phase of the REML project, most of the major assets have been installed in a manufacturing line arrangement featuring a green cell, a thermal treatment cell and a finishing cell. Most of the secondary and support assets have been acquired and installed. Assets have been integrated with a commercial, machine-tending gantry robot in the thermal treatment cell and with a low-mass, high-speed gantry robot in the finish cell. Capabilities for masterless gauging of product’s dimensional and form characteristics were advanced. Trial production runs across the entire REML line have been undertaken. Discrete event simulation modeling has aided in line balancing and reduction of flow time. Energy, productivity and cost, and environmental comparisons to baselines have been made. Energy The REML line in its current state of development has been measured to be about 22% (338,000 kVA-hrs) less energy intensive than the baseline conventional low volume line assuming equivalent annual production volume of approximately 51,000 races. The reduction in energy consumption is largely attributable to the energy reduction in the REML thermal treatment cell where the heating devices are energized on demand and are appropriately sized to the heating load of a near single piece flow line. If additional steps such as power factor correction and use of high-efficiency motors were implemented to further reduce energy consumption, it is estimated, but not yet demonstrated, that the REML line would be about 30% less energy intensive than the baseline conventional low volume line assuming equivalent annual production volume. Productivity The capital cost of an REML line would be roughly equivalent to the capital cost of a new conventional line. The

  11. Advanced optimization algorithms for sensor arrays and multi-antenna communications

    OpenAIRE

    Abrudan, Traian

    2008-01-01

    Optimization problems arise frequently in sensor array and multi-channel signal processing applications. Often, optimization needs to be performed subject to a matrix constraint. In particular, unitary matrices play a crucial role in communications and sensor array signal processing. They are involved in almost all modern multi-antenna transceiver techniques, as well as sensor array applications in biomedicine, machine learning and vision, astronomy and radars. In this thesis, algorithms...

  12. Topology optimization and digital assembly of advanced space-frame structures

    DEFF Research Database (Denmark)

    Søndergaard, Asbjørn; Amir, Oded; Michael, Knauss

    2014-01-01

    this paper presents a novel method for integrated design, optimization and fabrication of optimized space-frame structures in an autonomous, digital process. Comparative numerical studies are presented, demonstrating achievable mass reduction by application of the method by comparison to equivalent...... to normative space truss designs and dimensions. As such, a principal digital fabrication and assembly scheme is developed, where an architectural design methodology relative to the described process is established, and the proposed process demonstrated through scaled digital fabrication experiments....

  13. NATURE INSPIRED OPTIMAL DESIGN OF HEAT CONVEYING NETWORKS FOR ADVANCED FIBER-REINFORCED COMPOSITES

    OpenAIRE

    Kizilova, Natalya

    2015-01-01

    A concept of composite materials reinforced by branching micro or nanotubes optimized for both heat transfer and strength of the material is presented. Numerous examples of reinforcement by branched fibers in cells, tissues and organs of plants and animals are studied. It is shown orientation of the fibers according to principals of the stress tensor at given external load is the main principle of optimal reinforcement in nature. The measurement data obtained on venations of the plant leaves ...

  14. Genetic algorithm based optimization of advanced solar cell designs modeled in Silvaco AtlasTM

    OpenAIRE

    Utsler, James

    2006-01-01

    A genetic algorithm was used to optimize the power output of multi-junction solar cells. Solar cell operation was modeled using the Silvaco ATLASTM software. The output of the ATLASTM simulation runs served as the input to the genetic algorithm. The genetic algorithm was run as a diffusing computation on a network of eighteen dual processor nodes. Results showed that the genetic algorithm produced better power output optimizations when compared with the results obtained using the hill cli...

  15. An advanced STATCOM model for optimal power flows using Newton's method.

    OpenAIRE

    Kazemtabrizi, B.; Acha, E.

    2014-01-01

    This paper presents the optimal power flow (OPF) formulation of a recent power flow STATCOM model. The new model puts forward an alternative, insightful interpretation of the fundamental frequency operation of the PWM-controlled voltage source converter (VSC), in an optimal fashion. The new model makes provisions for the explicit representation of the converter's internal ohmic and switching losses which in the context of an OPF formulation, yields an optimum operating point at which these po...

  16. Real-time Traffic State Prediction: Modeling and Applications

    OpenAIRE

    Chen, Hao

    2014-01-01

    Travel-time information is essential in Advanced Traveler Information Systems (ATISs) and Advanced Traffic Management Systems (ATMSs). A key component of these systems is the prediction of the spatiotemporal evolution of roadway traffic state and travel time. From the perspective of travelers, such information can result in better traveler route choice and departure time decisions. From the transportation agency perspective, such data provide enhanced information with which to better manage a...

  17. WSN Applications: Automated Intelligent Traffic Control System Using Sensors

    OpenAIRE

    Rashid Hussain; Sandhyasharma; Vinita Sharma; Sandhya Sharma

    2013-01-01

    In this new Era the growing Vehicle population in all developing and developed country calls for a major improvement and innovation in the existing Traffic Signaling systems. The most widely used automated system uses a simple time based system which working on a time interval basis which is now inefficient for random and non uniform Traffic. Advance automated systems in testing use image processing techniques or advance communication system with an intelligent information gathering systems i...

  18. Criticism of generally accepted fundamentals and methodologies of traffic and transportation theory

    International Nuclear Information System (INIS)

    It is explained why the set of the fundamental empirical features of traffic breakdown (a transition from free flow to congested traffic) should be the empirical basis for any traffic and transportation theory that can be reliable used for control and optimization in traffic networks. It is shown that generally accepted fundamentals and methodologies of traffic and transportation theory are not consistent with the set of the fundamental empirical features of traffic breakdown at a highway bottleneck. To these fundamentals and methodologies of traffic and transportation theory belong (i) Lighthill-Whitham-Richards (LWR) theory, (ii) the General Motors (GM) model class (for example, Herman, Gazis et al. GM model, Gipps’s model, Payne’s model, Newell’s optimal velocity (OV) model, Wiedemann’s model, Bando et al. OV model, Treiber’s IDM, Krauß’s model), (iii) the understanding of highway capacity as a particular stochastic value, and (iv) principles for traffic and transportation network optimization and control (for example, Wardrop’s user equilibrium (UE) and system optimum (SO) principles). Alternatively to these generally accepted fundamentals and methodologies of traffic and transportation theory, we discuss three-phase traffic theory as the basis for traffic flow modeling as well as briefly consider the network breakdown minimization (BM) principle for the optimization of traffic and transportation networks with road bottlenecks

  19. Criticism of generally accepted fundamentals and methodologies of traffic and transportation theory: A brief review

    Science.gov (United States)

    Kerner, Boris S.

    2013-11-01

    It is explained why the set of the fundamental empirical features of traffic breakdown (a transition from free flow to congested traffic) should be the empirical basis for any traffic and transportation theory that can be reliably used for control and optimization in traffic networks. It is shown that the generally accepted fundamentals and methodologies of the traffic and transportation theory are not consistent with the set of the fundamental empirical features of traffic breakdown at a highway bottleneck. To these fundamentals and methodologies of the traffic and transportation theory belong (i) Lighthill-Whitham-Richards (LWR) theory, (ii) the General Motors (GM) model class (for example, Herman, Gazis et al. GM model, Gipps’s model, Payne’s model, Newell’s optimal velocity (OV) model, Wiedemann’s model, Bando et al. OV model, Treiber’s IDM, Krauß’s model), (iii) the understanding of highway capacity as a particular (fixed or stochastic) value, and (iv) principles for traffic and transportation network optimization and control (for example, Wardrop’s user equilibrium (UE) and system optimum (SO) principles). Alternatively to these generally accepted fundamentals and methodologies of the traffic and transportation theory, we discuss the three-phase traffic theory as the basis for traffic flow modeling as well as briefly consider the network breakdown minimization (BM) principle for the optimization of traffic and transportation networks with road bottlenecks.

  20. Local traffic control of microregion

    Czech Academy of Sciences Publication Activity Database

    Homolová, Jitka; Nagy, Ivan

    Adelaide: Advanced Knowledge International, 2004 - (Andrýsek, J.; Kárný, M.; Kracík, J.), s. 161-171. (International Series on Advanced Intelligence.. 9). ISBN 0-9751004-5-9. [Workshop on Computer-Intensive Methods in Control and Data Processing 2004. Prague (CZ), 12.05.2004-14.05.2004] R&D Projects: GA MDS 1F43A/003/120 Grant ostatní: SOCRATES(XE) 110330-CP-1-2003-1-ES Institutional research plan: CEZ:AV0Z1075907 Keywords : traffic control * linear programming * Kalman filter Subject RIV: BC - Control Systems Theory http://library.utia.cas.cz/prace/20040054.pdf

  1. VBR video traffic models

    CERN Document Server

    Tanwir, Savera

    2014-01-01

    There has been a phenomenal growth in video applications over the past few years. An accurate traffic model of Variable Bit Rate (VBR) video is necessary for performance evaluation of a network design and for generating synthetic traffic that can be used for benchmarking a network. A large number of models for VBR video traffic have been proposed in the literature for different types of video in the past 20 years. Here, the authors have classified and surveyed these models and have also evaluated the models for H.264 AVC and MVC encoded video and discussed their findings.

  2. Road Traffic Injuries

    Institute of Scientific and Technical Information of China (English)

    WANG Zheng-guo

    2005-01-01

    @@ As everybody knows that automobiles have been greatly changing our life. However, everything has two sides, motor vehicles have also caused a huge number of people's deaths, injuries and property damage. Traffic crashes are perhaps the number one public health problem in developed countries [1]. In the United States, pre-retirement years of life lost in traffic crashes are more than that of the two combined leading diseases: cancer and heart disease [1]. Today road traffic crash (RTC) ranks 11th in leading cause of death and accounts for 2.1% of all deaths globally.

  3. Optimization

    CERN Document Server

    Pearce, Charles

    2009-01-01

    Focuses on mathematical structure, and on real-world applications. This book includes developments in several optimization-related topics such as decision theory, linear programming, turnpike theory, duality theory, convex analysis, and queuing theory.

  4. Routing strategies in traffic network and phase transition in network traffic flow

    Indian Academy of Sciences (India)

    Bing-Hong Wang; Wen-Xu Wang

    2008-08-01

    The dynamics of information traffic over scale-free networks has been investigated systematically. A series of routing strategies of data packets have been proposed, including the local routing strategy, the next-nearest-neighbour routing strategy, and the mixed routing strategy based on local static and dynamic information. The capacity of the network can be quantified by the phase transition from free flow state to congestion state. The optimal parameter values of each model leading to the highest efficiency of scale-free networked traffic systems have been found. Moreover, we have found hysteretic loop in networked traffic systems with finite packets delivering ability. Such hysteretic loop indicates the existence of the bi-stable state in the traffic dynamics over scale-free networks.

  5. Two dimensional mixed traffic flow considering the transit traffic

    OpenAIRE

    Lingjiang Kong; Junhui Hu; Li Yang

    2012-01-01

    Based on the two-dimension cellular automaton traffic flow model (BML model), a mixed traffic flow model for urban traffic considering the transit traffic is established in this paper by using the Don't block the box rules. We have investigated the influences of the transit traffic ratio, and found that, in most cases, the urban traffic flow exhibited jam phase. Moreover, focusing on the traffic lights cycle, it is found that the average flow has the periodic fluctuation phenomenon, and we ha...

  6. Local and nonlocal information in a traffic network: how important is the horizon?

    International Nuclear Information System (INIS)

    Recent advances in distributed sensor network technology have changed the landscape of traffic optimization in which small, mobile devices are able to sense local information and communicate in real time with one another. Naive optimization algorithms that operate solely on the local or global level are inherently flawed, as global optimization requires every local sensor to communicate with a centralized base-station, creating prohibitive bandwidth, robustness, and security concerns, while local optimization methods are limited by a near information horizon as they are unable to propagate or react to information beyond their immediate vicinity. This paper investigates an intermediate approach where individual sensors are able to propagate congestion information over a variable distance that is determined in real-time. This strategy consistently out-performs a naive strategy where every car simply takes the shortest path to its destination, but does worse than a simpler optimization algorithm that only incorporates local information. This is most likely because the intermediate solution directs cars along the same alternate path when attempting to free a congested area, thus creating new congestion along the detour. The results suggest that local information might set an upper bound on performance in models of cascading in- formation. Further work is required to confirm this observation and develop an algorithm able to join both local and global information to effectively diffuse traffic around congestion. (author)

  7. A Propose-and-revise System for Real-time Traffic Management

    OpenAIRE

    Molina, Martin; Robledo, Monica; Fernandez, Alberto

    2000-01-01

    The aim of this paper is to describe an intelligent system for the problem of real time road traffic control. The purpose of the system is to help traffic engineers in the selection of the state of traffic control devices on real time, using data recorded by traffic detectors on motorways. The system follows an advanced knowledge-based approach that implements an abstract generic problem solving method, called propose-and-revise, which was proposed in Artificial Intelligence, within the knowl...

  8. Review of urban traffic management and the impacts of new vehicle technologies

    OpenAIRE

    Hounsell, N.B.; Shrestha, B. P.; Piao, J.; McDonald, M

    2009-01-01

    Traffic congestion is a growing problem in most urban areas across the world. In recent years, the problem has often been tackled by management of existing capacity rather than the traditional concept of more road building. This requires efficient traffic management tools and has led to widespread implementation of advanced traffic control systems integrated within a wider urban traffic management (UTM) environment. UTM systems collect data from various sources, process and manage the data an...

  9. Automatic Incident Classification for Big Traffic Data by Adaptive Boosting SVM

    OpenAIRE

    Wang, Li-li; Ngan, Henry Y. T.; Yung, Nelson H. C.

    2015-01-01

    Modern cities experience heavy traffic flows and congestions regularly across space and time. Monitoring traffic situations becomes an important challenge for the Traffic Control and Surveillance Systems (TCSS). In advanced TCSS, it is helpful to automatically detect and classify different traffic incidents such as severity of congestion, abnormal driving pattern, abrupt or illegal stop on road, etc. Although most TCSS are equipped with basic incident detection algorithms, they are however cr...

  10. Effects of node buffer and capacity on network traffic

    International Nuclear Information System (INIS)

    In this paper, we study the optimization of network traffic by considering the effects of node buffer ability and capacity. Two node buffer settings are considered. The node capacity is considered to be proportional to its buffer ability. The node effects on network traffic systems are studied with the shortest path protocol and an extension of the optimal routing [Phys. Rev. E 74 046106 (2006)]. In the diagrams of flux—density relationships, it is shown that a nodes buffer ability and capacity have profound effects on the network traffic

  11. A Network Traffic Control Enhancement Approach over Bluetooth Networks

    DEFF Research Database (Denmark)

    Son, L.T.; Schiøler, Henrik; Madsen, Ole Brun;

    2003-01-01

    This paper analyzes network traffic control issues in Bluetooth data networks as convex optimization problem. We formulate the problem of maximizing of total network flows and minimizing the costs of flows. An adaptive distributed network traffic control scheme is proposed as an approximated...... solution of the stated optimization problem that satisfies quality of service requirements and topologically induced constraints in Bluetooth networks, such as link capacity and node resource limitations. The proposed scheme is decentralized and complies with frequent changes of topology as well...... as capacity limitations and flow requirements in the network. Simulation shows that the performance of Bluetooth networks could be improved by applying the adaptive distributed network traffic control scheme...

  12. Fronthaul dimensioning in C-RAN with web traffic for coordinated multipoint joint transmission

    DEFF Research Database (Denmark)

    Artuso, Matteo; Christiansen, Henrik Lehrmann

    2015-01-01

    The use of centralized signal processing for dense urban mobile networks is gaining interest both in research and in industry. Gathering most of the base station functionalities in a processing pool would enable capacity sharing and the implementation of advanced techniques such as coordinated mu....... We model the full protocol stack for the network end-to-end in order to use realistic application-layer traffic and user behavior models. Our results show that the fronthaul latency should be kept below 0.6 ms in order to ensure optimal performances for the application...

  13. A method for efficient evaluation of measures for climate optimization of air traffic; Eine Methode zur effizienten Bewertung vo Massnahmen zur Klimaoptimierung des Luftverkehrs

    Energy Technology Data Exchange (ETDEWEB)

    Dahlmann, Katrin

    2012-11-01

    For calculating the climate impact of aviation it is important to consider the effect of so-called non-CO{sub 2} emissions beside the climate effect of carbon dioxide emissions. As the impact of these non-CO{sub 2} emissions strongly depends on the location of the emission, the climate impact is no longer proportional to the total amount of emissions. Therefore it is necessary to use an efficient model which considers the impact of different climate agents as well as their geographically variable impact for calculating the climate impact of aviation emissions. Such a model (AirClim) was expanded to consider primary mode ozone and contrail-cirrus as well as uncertainties in the evaluation of different measures by using a Monte-Carlo simulation. Afterward the mitigation gain of changing flight altitude and speed of nowadays aircrafts was evaluated. This shows that it would be possible to reduce the climate impact by more than 60% by optimizing the flight altitude and speed, leading to an increase in direct operating costs by 32%. A one percentage increase in direct operating cost can results in a 12% reduction in climate impact. (orig.)

  14. Traffic Accident Prediction Model Implementation in Traffic Safety Management

    OpenAIRE

    Wen, Keyao

    2009-01-01

    As one of the highest fatalities causes, traffic accidents and collisions always requires a large amounteffort to be reduced or prevented from occur. Traffic safety management routines therefore always needefficient and effective implementation due to the variations of traffic, especially from trafficengineering point of view apart from driver education.Traffic Accident Prediction Model, considered as one of the handy tool of traffic safety management,has become of well followed with interest...

  15. Functional Requirements to Support Traffic Organization Service

    Directory of Open Access Journals (Sweden)

    Jung Sik Jeong

    2013-03-01

    Full Text Available In the era of e-Navigation, the future VTS is anticipated to play an important role on the enhancement of maritime safety and the efficiency of maritime transport as a key stakeholder of e-Navigation. The VTS services need the advanced Traffic Organization Service(TOS. In this paper, the VTS functions for TOS is revisited from the reports of IMO e-Navigation Correspondence Group and IALA VTS Committee. In Korea, the research activities to enhance the existing VTS functions have been conducted. In terms of TOS, some VTS functions have been developed. In conclusion, all the past traffic data and real-time ship data are required to provide the advanced TOS. For this, the advanced functions to support TOS should be implemented on VTS console.

  16. SUBSTATIATION AND CHOICE OF ROAD TRAFFIC AUTOMATIC CONTROL SYSTEM SPECIAL FACILITY

    OpenAIRE

    Shasha, I.

    2007-01-01

    The analysis of potential ecological hazard usage efficiency and reduction of avarage length of human life for road traffic management has been done. It has been proved that the application of these characteristics will be efficient in case of high traffic volume. It is suggested to use the total value of road vehicle delay time at urban road network crossings as an universal special function of road traffic management optimization. During one traffic control cycle.

  17. Efficiency of the Traffic Control and Management System measures in potentially dangerous situations on highway

    OpenAIRE

    Zupančič Demšar, Metka

    2011-01-01

    The Traffic Control and Management System (TCMS) is implemented on the five most critical sections of Slovenian highways with the purpose to re-establish the optimal traffic conditions in case of potentially dangerous situations on the road. The main goal of the informing and the traffic management is to increase traffic safety as well as decrease congestions and minimise negative impact on the environment. The objective of this study is to evaluate efficiency of the TCMS measures in the area...

  18. Turning Traffic Jams to Jelly

    Institute of Scientific and Technical Information of China (English)

    LI LI

    2010-01-01

    @@ Beijing, known for having the worst traffic in China, is brewing up a traffic plan with the harshest ever measures to ensure smooth traffic flow as the capital's gridlock during rush hour and private car sales soar. On December 13, the Beijing Municipal Government started soliciting public opinions for a draft plan designed to relieve the city's traffic problems.

  19. Traffic-Adaptive Routing

    OpenAIRE

    Kammenhuber, Nils

    2011-01-01

    Despite the bursty and highly volatile traffic, routing in the Internet today is optimised only on coarse time scales, as load-adaptive routing is known to induce performance deterioration by causing massive oscillations. We describe ReplEx, an universally applicable distributed algorithm for dynamic routing/traffic engineering, which is based on game theory. We show through extensive realistic simulations that ReplEx does not oscillate, and that it achieves performance gains comparable to tr...

  20. Traffic engineering eye diagram

    OpenAIRE

    Kowalik, Karol; Collier, Martin

    2005-01-01

    It is said that a picture is worth a thousand words - this statement also applies to networking topics. Thus, to effectively monitor network performance we need tools which present the performance metrics in a graphical way which is also clear and informative. We propose a tool for this purpose which we call the traffic engineering eye diagram (TEED). Eye diagrams are used in digital communications to analyse the quality of a digital signal; the TEED can similarly he used in the traffic engin...

  1. Traffic Management Systems

    OpenAIRE

    Wei Chen; David Levinson

    2004-01-01

    This study uses regression analysis to evaluate long-run traffic management system performance. Three important traffic management systems in the Twin Cities metro area - Ramp Metering, Variable Message Signs (VMS), and Freeway Service Patrol (the Highway Helper Program) were evaluated with multiple regression models to predict link speed and incident rate. We find that ramp meters increase freeway link speed and reduce incident rate. Freeway Service Patrols increase link speed when incidents...

  2. Penalties in traffic.

    OpenAIRE

    2009-01-01

    Traffic offenders are penalized in various ways: fines, (temporary) driving licence suspensions, confiscation of their vehicles, penalty points, mandatory participation in rehabilitation programmes, prison sentences or community service. The aim of penalties is to punish offenders, to protect society and to influence the behaviour of offenders and all citizens (prevention). Many studies have found that the combination of enforcement and penalties prevent the violation of traffic regulations a...

  3. LTE-Advanced Radio and Network Optimization: Basic Coverage and Interference Constraints

    DEFF Research Database (Denmark)

    Velez, Fernando J.; Sousa, Sofia; Flores, Jessica Acevedo;

    2016-01-01

    In cellular optimization, the UL and DL the values from carrier-to-noise-plus-interference ratio (CNIR) from/at the mobile station are very important parameters. From a detailed analysis of its variation with the coverage and reuse distances for different values of the Channel Quality Indicator...

  4. Artificial neural network to support thermohydraulic design optimization for an advanced nuclear heat removal system

    International Nuclear Information System (INIS)

    The U.S. Department of Energy (DOE) is leading a number of initiatives, including one known as the Next Generation Nuclear Plant (NGNP) project. One of the NGNP nuclear system concepts is the Very High Temperature (gas-cooled) Reactor (VHTR) that may be coupled to a hydrogen generating plant to support the anticipated hydrogen economy. For the NGNP, an efficient power conversion system using an Intermediate Heat Exchanger (IHX) is key to electricity and/or process heat generation (hydrogen production). Ideally, it's desirable for the IHX to be compact and thermally efficient. However, traditional heat exchanger design practices do not assure that the design parameters are optimized. As part of NGNP heat exchanger design and optimization project, this research paper thus proposes developing a recurrent-type Artificial Neural Network (ANN), the Hopfield Network (HN) model, in which the activation function is modified, as a design optimization approach to support a NGNP thermal system candidate, the Printed Circuit Heat Exchanger (PCHE). Four quadratic functions, available in literature, were used to test the presented methodology. The results computed by an artificially intelligent approach were compared to another approach, the Genetic Algorithm (GA). The results show that the HN results are close to GA in optimization of multi-variable second-order equations. (author)

  5. Advanced tools for modeling, design and optimization of wind turbine systems

    DEFF Research Database (Denmark)

    Iov, F.; Hansen, A.D.; Jauch, C.; Sørensen, Poul Ejnar; Blaabjerg, F.

    2005-01-01

    overview of a developed simulation platform for the modeling, design and optimization of wind turbines. The ability to simulate the dynamic behavior of wind turbines and the wind turbine grid interaction using four simulation tools (Matlab, Saber, DIgSILENT and HAWC) is investigated, improved and extended....

  6. Advanced Tools for Modeling, Design and Optimization of Wind Turbine Systems

    DEFF Research Database (Denmark)

    Iov, Florin; Hansen, Anca-Daniela; Jauch, Clemens; Sorensen, Poul; Blaabjerg, Frede

    2005-01-01

    overview of a developed simulation platform for the modeling, design and optimization of wind turbines. The ability to simulate the dynamic behavior of wind turbines and the wind turbine grid interaction using four simulation tools (Matlab, Saber, DIgSILENT and HAWC) is investigated, improved and extended....

  7. Advanced Tools for Modelling, Design and Optimization of Wind Turbine Systems

    DEFF Research Database (Denmark)

    Iov, Florin; Hansen, A. D.; Soerensen, P.; Blaabjerg, Frede

    2004-01-01

    ! Henvisningskilde ikke fundet. . This paper makes an overview of a developed simulation platform for modeling, design and optimization of wind turbines. The ability to simulate the dynamic behavior of the wind turbines and the wind turbine grid interaction of four simulation tools (Matlab, Saber, DIgSILENT and HAWC...

  8. Consideration of a design optimization method for advanced nuclear power plant thermal-hydraulic components

    International Nuclear Information System (INIS)

    In order to meet the global energy demand and also mitigate climate change, we anticipate a significant resurgence of nuclear power in the next 50 years. Globally, Generation III plants (ABWR) have been built; Gen' III+ plants (EPR, AP1000 others) are anticipated in the near term. The U.S. DOE and Japan are respectively pursuing the NGNP and MSFR. There is renewed interest in closing the fuel cycle and gradually introducing the fast reactor into the LWR-dominated global fleet. In order to meet Generation IV criteria, i.e. thermal efficiency, inherent safety, proliferation resistance and economic competitiveness, plant and energy conversion system engineering design have to increasingly meet strict design criteria with reduced margin for reliable safety and uncertainties. Here, we considered a design optimization approach using an anticipated NGNP thermal system component as a Case Study. A systematic, efficient methodology is needed to reduce time consuming trial-and-error and computationally-intensive analyses. We thus developed a design optimization method linking three elements; that is, benchmarked CFD used as a 'design tool', artificial neural networks (ANN) to accommodate non-linear system behavior and enhancement of the 'design space', and finally, response surface methodology (RSM) to optimize the design solution with targeted constraints. The paper presents the methodology including guiding principles, an integration of CFD into design theory and practice, consideration of system non-linearities (such as fluctuating operating conditions) and systematic enhancement of the design space via application of ANN, and a stochastic optimization approach (RSM) with targeted constraints. Results from a Case Study optimizing the printed circuit heat exchanger for the NGNP energy conversion system will be presented. (author)

  9. Dynamic statistical optimization of GNSS radio occultation bending angles: an advanced algorithm and its performance analysis

    Directory of Open Access Journals (Sweden)

    Y. Li

    2015-01-01

    Full Text Available We introduce a new dynamic statistical optimization algorithm to initialize ionosphere-corrected bending angles of Global Navigation Satellite System (GNSS based radio occultation (RO measurements. The new algorithm estimates background and observation error covariance matrices with geographically-varying uncertainty profiles and realistic global-mean correlation matrices. The error covariance matrices estimated by the new approach are more accurate and realistic than in simplified existing approaches and can therefore be used in statistical optimization to provide optimal bending angle profiles for high-altitude initialization of the subsequent Abel transform retrieval of refractivity. The new algorithm is evaluated against the existing Wegener Center Occultation Processing System version 5.6 (OPSv5.6 algorithm, using simulated data on two test days from January and July 2008 and real observed CHAMP and COSMIC measurements from the complete months of January and July 2008. The following is achieved for the new method's performance compared to OPSv5.6: (1 significant reduction in random errors (standard deviations of optimized bending angles down to about two-thirds of their size or more; (2 reduction of the systematic differences in optimized bending angles for simulated MetOp data; (3 improved retrieval of refractivity and temperature profiles; (4 produces realistically estimated global-mean correlation matrices and realistic uncertainty fields for the background and observations. Overall the results indicate high suitability for employing the new dynamic approach in the processing of long-term RO data into a reference climate record, leading to well characterized and high-quality atmospheric profiles over the entire stratosphere.

  10. Ant traffic rules.

    Science.gov (United States)

    Fourcassié, Vincent; Dussutour, Audrey; Deneubourg, Jean-Louis

    2010-07-15

    Many animals take part in flow-like collective movements. In most species, however, the flow is unidirectional. Ants are one of the rare group of organisms in which flow-like movements are predominantly bidirectional. This adds to the difficulty of the task of maintaining a smooth, efficient movement. Yet, ants seem to fare well at this task. Do they really? And if so, how do such simple organisms succeed in maintaining a smooth traffic flow, when even humans experience trouble with this task? How does traffic in ants compare with that in human pedestrians or vehicles? The experimental study of ant traffic is only a few years old but it has already provided interesting insights into traffic organization and regulation in animals, showing in particular that an ant colony as a whole can be considered as a typical self-organized adaptive system. In this review we will show that the study of ant traffic can not only uncover basic principles of behavioral ecology and evolution in social insects but also provide new insights into the study of traffic systems in general. PMID:20581264

  11. Design and Performance Optimizations of Advanced Erosion-Resistant Low Conductivity Thermal Barrier Coatings for Rotorcraft Engines

    Science.gov (United States)

    Zhu, Dongming; Miller, Robert A.; Kuczmarski, Maria A.

    2012-01-01

    Thermal barrier coatings will be more aggressively designed to protect gas turbine engine hot-section components in order to meet future rotorcraft engine higher fuel efficiency and lower emission goals. For thermal barrier coatings designed for rotorcraft turbine airfoil applications, further improved erosion and impact resistance are crucial for engine performance and durability, because the rotorcraft are often operated in the most severe sand erosive environments. Advanced low thermal conductivity and erosion-resistant thermal barrier coatings are being developed, with the current emphasis being placed on thermal barrier coating toughness improvements using multicomponent alloying and processing optimization approaches. The performance of the advanced thermal barrier coatings has been evaluated in a high temperature erosion burner rig and a laser heat-flux rig to simulate engine erosion and thermal gradient environments. The results have shown that the coating composition and architecture optimizations can effectively improve the erosion and impact resistance of the coating systems, while maintaining low thermal conductivity and cyclic oxidation durability

  12. Performance analysis and optimization of an advanced pharmaceutical wastewater treatment plant through a visual basic software tool (PWWT.VB).

    Science.gov (United States)

    Pal, Parimal; Thakura, Ritwik; Chakrabortty, Sankha

    2016-05-01

    A user-friendly, menu-driven simulation software tool has been developed for the first time to optimize and analyze the system performance of an advanced continuous membrane-integrated pharmaceutical wastewater treatment plant. The software allows pre-analysis and manipulation of input data which helps in optimization and shows the software performance visually on a graphical platform. Moreover, the software helps the user to "visualize" the effects of the operating parameters through its model-predicted output profiles. The software is based on a dynamic mathematical model, developed for a systematically integrated forward osmosis-nanofiltration process for removal of toxic organic compounds from pharmaceutical wastewater. The model-predicted values have been observed to corroborate well with the extensive experimental investigations which were found to be consistent under varying operating conditions like operating pressure, operating flow rate, and draw solute concentration. Low values of the relative error (RE = 0.09) and high values of Willmott-d-index (d will = 0.981) reflected a high degree of accuracy and reliability of the software. This software is likely to be a very efficient tool for system design or simulation of an advanced membrane-integrated treatment plant for hazardous wastewater. PMID:26856870

  13. Traffic Congestion Mechanism in Two Ramp Systems

    International Nuclear Information System (INIS)

    The aim of this paper is to study traffic properties in an on/off-ramp system with a bus stop close to the on/off ramp. The location of the bus stop in the on/off-ramp (thereafter downstream or upstream case) is discussed. The simulation results show that in the two ramp systems, the reasons for traffic congestions are different. In the on-ramp system, buses and cars coming from on-ramp interweave each other, while in the off-ramp system, buses interweave with cars exiting to off-ramp. Thus, in the on-ramp (off-ramp) system, the upstream (downstream) bus stop is helpful to reduce the interweaving situation. Moreover, the negative effect will disappear when the distance between the bus stop and the on/off-ramp is more than 20 cells (i.e. 150 m). These qualitative findings may provide some suggestions on traffic management and optimization. (general)

  14. A Cooperative Traffic Control Strategy

    OpenAIRE

    BORG, Dora Lee; Bhouri, Neila; SCERRI, Kenneth

    2015-01-01

    With one-third of the global population living in cities by 2030 and the need for mobility fueling traffic growth all over the world, the traffic congestion problem in major cities is becoming more and more acute. Besides economic losses, traffic congestion has detrimental effects on our standard of living and on the environment. A viable solution to the traffic congestion problem is intelligent traffic control. The main aim of this work is to test a Model Predictive Control Strategy (MPC) on...

  15. Traffic violation alert and management

    OpenAIRE

    Aliane, Nourdine; Fernández Andrés, Javier; Bemposta Rosende, Sergio; Mata Ortega, Mario

    2011-01-01

    The present paper presents an in-vehicle system for traffic violation alert and management. The system hardware consists of a combination of an on-board computer vision system for traffic sign detection and recognition with a data recorder device for traffic violation alert and management. At present, traffic violations are only focused on three signs: namely speed limit, stop sign, and forbidden turning. The system is designed to warn drivers about potential traffic violations by emitting ac...

  16. Traffic Information System for Hanoi

    OpenAIRE

    Sohr, Alexander; Brockfeld, Elmar; Sauerländer-Biebl, Anke; Melde, Eric

    2016-01-01

    To improve the traffic situation in Hanoi it is necessary to have a good overview of the existing traffic situation and to monitor the development of the traffic over longer time periods. Floating Car Data (FCD) Systems can help to acquire area wide traffic information; here a FCD system based on taxis, busses and motor-cycles is described. It consists of Web and App tools and a Hotspot-Monitoring for long term traffic analysis.

  17. A conservation approach to pharyngeal carcinoma with advanced neck disease: optimizing neck management

    OpenAIRE

    Allal, Abdelkarim Said; Dulguerov, Pavel; Bieri, Sabine; Lehmann, Willy; Kurtz, John

    1999-01-01

    Surgical management of advanced neck disease remains controversial when a conservative approach based on radiotherapy is retained for primary tumors. The objective of this study was to evaluate retrospectively treatment results in pharyngeal cancers presenting with N2-N3 neck disease, using neck dissection followed by radical locoregional radiotherapy (RT) and to compare these results with those obtained in patients treated by radical RT alone.

  18. System design impacts on optimization of the advanced radioisotope power system (ARPS) AMTEC cell

    International Nuclear Information System (INIS)

    Several NASA deep space missions require Advanced Radioisotope Power Systems (ARPS) to supply spacecraft power for various internal functions and mission instruments and experiments. AMTEC (Alkali-Metal Thermal-Electric Conversion) power conversion is the DOE-selected technology for an advanced, next- generation RPS to power these spacecraft. Advanced Modular Power Systems, Inc. (AMPS) has begun investigating the design of an AMTEC-based ARPS using the General Purpose Heat Source (GPHS) and the latest PX-5 AMTEC cell technology with refractory materials in critical components. This paper presents and discusses the system design methodology, and results of important system design tradeoffs and system design impacts on the ARPS AMTEC cell design. This work investigated dual 2-GPHS system configurations and 4-GPHS system configurations with 16 side-mounted AMTEC cells operating at beginning-of-mission (BOM) and end-of-mission (EOM) GPHS heat dissipation conditions. Current design studies indicate using a refractory material AMTEC cell with 8-BASE tubes, 5.0 inches long, and 1.75 inches diameter in the 4-GPHS system configuration is the strongest design candidate to satisfy system performance requirements

  19. Adaptable structural synthesis using advanced analysis and optimization coupled by a computer operating system

    Science.gov (United States)

    Sobieszczanski-Sobieski, J.; Bhat, R. B.

    1979-01-01

    A finite element program is linked with a general purpose optimization program in a 'programing system' which includes user supplied codes that contain problem dependent formulations of the design variables, objective function and constraints. The result is a system adaptable to a wide spectrum of structural optimization problems. In a sample of numerical examples, the design variables are the cross-sectional dimensions and the parameters of overall shape geometry, constraints are applied to stresses, displacements, buckling and vibration characteristics, and structural mass is the objective function. Thin-walled, built-up structures and frameworks are included in the sample. Details of the system organization and characteristics of the component programs are given.

  20. Advances of radioisotope for design, intensification and optimization of processes and operations in chemical industry

    International Nuclear Information System (INIS)

    Full text: In chemical industries different processes and operations involve a variety of multiphase contacting schemes for optimal production schedule in terms of ease of handling, time and money. A number of parameters will have to be optimized for this purpose. Further more, during the operation of a process plant, a number of problems such as reduction in process efficiency, deterioration in product quality etc. are encountered due to malfunctioning of one or more components. The successful operation of an industry depends on the early detection of the problems for appropriate remedial action. These are conveniently carried out by the application of radioisotopes either directly or in sealed condition depending upon the problem to be addressed. In this talk both types of radiotracer applications are discussed by taking specific examples

  1. Nonlinear System Modeling, Optimal Cam Design, and Advanced System Control for an Electromechanical Engine Valve Drive

    OpenAIRE

    Qiu, Yihui; Perreault, David J.; Keim, Thomas A.; Kassakian, John G.

    2011-01-01

    A cam-based shear force-actuated electromechanical valve drive system offering variable valve timing in internal combustion engines was previously proposed and demonstrated. To transform this concept into a competitive commercial product, several major challenges need to addressed, including the reduction of power consumption, transition time, and size. As shown in this paper, by using nonlinear system modeling, optimizing cam design, and exploring different control strategies, the power cons...

  2. Research advances in coupling bionic optimization design method for CNC machine tools based on ergonomics

    OpenAIRE

    Shihao LIU; Yanbin DU; Guo, Zhizhong

    2015-01-01

    Currently, most Chinese CNC machine tools' dynamic and static performances have large gap comparing with the similar foreign products, and the CNC machine tools users' human-centered design demand are ignored, which results in that the domestic CNC machine tools' overall competitiveness is relatively low. In order to solve the above problem, the ergonomics and coupling bionics are adopted to study collaborative optimization design method for CNC machine tools based on the domestic and foreign...

  3. Development and Utilization of mathematical Optimization in Advanced Fuel Cycle Systems Analysis

    International Nuclear Information System (INIS)

    Over the past sixty years, a wide variety of nuclear power technologies have been theorized, investigated and tested to various degrees. These technologies, if properly applied, could provide a stable, long-term, economical source of CO2-free electric power. However, the recycling of nuclear fuel introduces a degree of coupling between reactor systems which must be accounted for when making long term strategic plans. This work investigates the use of a simulated annealing optimization algorithm coupled together with the VISION fuel cycle simulation model in order to identify attractive strategies from economic, evironmental, non-proliferation and waste-disposal perspectives, which each have associated an objective function. The simulated annealing optimization algorithm works by perturbing the fraction of new reactor capacity allocated to each available reactor type (using a set of heuristic rules) then evaluating the resulting deployment scenario outcomes using the VISION model and the chosen objective functions. These new scenarios, which are either accepted or rejected according the the Metropolis Criterion, are then used as the basis for further perturbations. By repeating this process several thousand times, a family of near-optimal solutions are obtained. Preliminary results from this work using a two-step, Once-through LWR to Full-recycle/FRburner deployment scenario with exponentially increasing electric demand indicate that the algorithm is capable of finding reactor deployment profiles that reduce the long-term-heat waste disposal burden relative to an initial reference scenario. Further work is under way to refine the current results and to extend them to include the other objective functions and to examine the optimization trade-offs that exist between these different objectives.

  4. Defining Requirements for Advanced PHM Technologies for Optimal Reliability Centered Maintenance

    OpenAIRE

    Millar, Richard C.

    2009-01-01

    Condition Based Maintenance Plus (CBM+) can be described as optimal condition based maintenance (CBM) procedures defined by applying the principles and process of Reliability Centered Maintenance. This approach offers a rigorous and disciplined method, based on the system FMECA, to determine the least cost maintenance policy and procedures that are consistent with acceptable levels of safety and readiness, applying available prognosis and health management tools.

  5. Development and Utilization of mathematical Optimization in Advanced Fuel Cycle Systems Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Turinsky, Paul; Hays, Ross

    2011-09-02

    Over the past sixty years, a wide variety of nuclear power technologies have been theorized, investigated and tested to various degrees. These technologies, if properly applied, could provide a stable, long-term, economical source of CO2-free electric power. However, the recycling of nuclear fuel introduces a degree of coupling between reactor systems which must be accounted for when making long term strategic plans. This work investigates the use of a simulated annealing optimization algorithm coupled together with the VISION fuel cycle simulation model in order to identify attractive strategies from economic, evironmental, non-proliferation and waste-disposal perspectives, which each have associated an objective function. The simulated annealing optimization algorithm works by perturbing the fraction of new reactor capacity allocated to each available reactor type (using a set of heuristic rules) then evaluating the resulting deployment scenario outcomes using the VISION model and the chosen objective functions. These new scenarios, which are either accepted or rejected according the the Metropolis Criterion, are then used as the basis for further perturbations. By repeating this process several thousand times, a family of near-optimal solutions are obtained. Preliminary results from this work using a two-step, Once-through LWR to Full-recycle/FRburner deployment scenario with exponentially increasing electric demand indicate that the algorithm is capable of nding reactor deployment pro les that reduce the long-term-heat waste disposal burden relative to an initial reference scenario. Further work is under way to re ne the current results and to extend them to include the other objective functions and to examine the optimization trade-o s that exist between these di erent objectives.

  6. Research advances in coupling bionic optimization design method for CNC machine tools based on ergonomics

    Directory of Open Access Journals (Sweden)

    Shihao LIU

    2015-06-01

    Full Text Available Currently, most Chinese CNC machine tools' dynamic and static performances have large gap comparing with the similar foreign products, and the CNC machine tools users' human-centered design demand are ignored, which results in that the domestic CNC machine tools' overall competitiveness is relatively low. In order to solve the above problem, the ergonomics and coupling bionics are adopted to study collaborative optimization design method for CNC machine tools based on the domestic and foreign machine tool design method research achievement. The CNC machine tools' "man-machine-environment" interaction mechanism can be built by combining with ergonomic, and then the CNC ergonomic design criteria is obtained. Taking the coupling bionics as theoretical basis, the biological structures "morphology-structure-function-adaptive growth" multiple coupling mechanism can be studied, and the mechanical performance benefits structure can be extracted, then the CNC machine tools structural coupling bionic design technology is obtained by combining with the similarity principle. Combination of CNC machine tools' ergonomic design criteria and coupling bionic design technology, and considering the CNC machine tool performance's interaction and coupling mechanisms, a new multi-objective optimization design method can be obtained, which is verified through CNC machine tools' prototype experiments. The new optimization design method for CNC machine tools can not only help improve the whole machine's dynamic and static performance, but also has a bright prospect because of the "man-oriented" design concept.

  7. On an optimized neutron shielding for an advanced molten salt fast reactor design

    International Nuclear Information System (INIS)

    The molten salt reactor technology has gained renewed interest. In contrast to the historic molten salt reactors, the current projects are based on designing a molten salt fast reactor. Thus the shielding becomes significantly more challenging than in historic concepts. One very interesting and innovative result of the most recent EURATOM project on molten salt reactors – EVOL – is the fluid flow optimized design of the inner core vessel using curved blanket walls. The developed structure leads to a very uniform flow distribution. The design avoids all core internal structures. On the basis of this new geometry a model for neutron physics calculation is presented and applied for a shielding optimization. Based on these results an optimized shielding strategy is developed for the molten salt fast reactor to keep the fluence in the safety related outer vessel below expected limit values. A lifetime of 80 years can be assured, but the size of the core/blanket system has to be significantly increased and will finally be comparable to a sodium cooled fast reactor. The HELIOS results are verified against Monte-Carlo calculations with very satisfactory agreement for a deep penetration problem. (author)

  8. Fuzzy peak hour for urban road traffic network

    Science.gov (United States)

    Tian, Zhao; Jia, Li-Min; Dong, Hong-Hui; Zhang, Zun-Dong; Ye, Yang-Dong

    2015-06-01

    Traffic congestion is now nearly ubiquitous in many urban areas and frequently occurs during rush hour periods. Rush hour avoidance is an effective way to ease traffic congestion. It is significant to calculate the rush hour for alleviating traffic congestion. This paper provides a method to calculate the fuzzy peak hour of the urban traffic network considering the flow, speed and occupancy. The process of calculation is based on betweenness centrality of network theory, optimal separation method, time period weighting, probability-possibility transformations and trapezoidal approximations of fuzzy numbers. The fuzzy peak hour of the urban road traffic network (URTN) is a trapezoidal fuzzy number [m1, m2, m3, m4]. It helps us (i) to confirm a more detailed traffic condition at each moment, (ii) to distinguish the five traffic states of the traffic network in one day, (iii) to analyze the characteristic of appearance and disappearance processes of the each traffic state and (iv) to find out the time pattern of residents travel in one city.

  9. Influences of overtaking on two-lane traffic with signals

    Science.gov (United States)

    Chen, Chen; Chen, Jianqiao; Guo, Xiwei

    2010-01-01

    Based on the cellular automata method (CA method), two-lane traffic flow with the consideration of overtaking is investigated. Discrete equations are proposed to describe the traffic dynamics by using the rules of CA model. Influences of signal cycle time ( ts) and vehicular density (ρ) on the mean velocity and mean overtaking times of the traffic flow are discussed. The effects of slow vehicles and road barricades on the traffic flow are also studied. Simulation results shows that the vehicular density and the signal cycle time have significant influences on the traffic flow. The mean velocity of the traffic flow could keep a comparatively large value when ρ≤0.45. For a certain value of ρ, displays a serrated fluctuation with ts. Therefore, there may exist a certain combination of ρ and ts which optimizes the traffic flow efficiency. As compared with the results in Nagatani (2009) [7], the model proposed here and the simulation results which took into account the effects of signal cycle time, slow vehicles, and road barricades on the traffic flow with overtaking allowed, can reflect the situation of traffic flow in a more realistic way.

  10. MATLAB Simulation of Fuzzy Traffic Controller for Multilane Isolated Intersection

    Directory of Open Access Journals (Sweden)

    Azura Che Soh/Lai Guan Rhung

    2010-07-01

    Full Text Available This paper presents a MATLAB simulation of fuzzy traffic controller for controlling traffic flow at multilane isolated signalized intersection. The controller is developed based on the waiting time and vehicles queue length at current green phase, and vehicles queue lengths at the other phases. For control strategy, the controllercontrols the traffic light timings and phase sequence to ensure smooth flow of traffic with minimal waiting time, queue length and delay time. In this research, the isolated intersection model used consists of two lanes in each approach. Each approach has two different values of vehicles queue length and waiting time, respectively, at the intersection. The maximum values of vehicles queue length and waiting times are selected as the inputs to controller for optimized control of traffic flows at the intersection. A traffic model and fuzzy traffic controller are developed to evaluate the performance of traffic controllers underdifferent conditions. In the end, by comparing the experimental result obtained by the vehicle-actuated controller (VAC and fuzzy traffic controller (FTC which improves significant performance for intersections, we confirmed the efficiency of our intelligent controller based fuzzy inference system.

  11. Decomposition with Thermoeconomic Isolation Applied to the Optimal Synthesis/Design of an Advanced Tactical Aircraft System

    Directory of Open Access Journals (Sweden)

    Michael R. von Spakovsky

    2003-09-01

    Full Text Available A decomposition methodology based on the concept of “thermoeconomic isolation” and applied to the synthesis/design and operational optimization of an advanced tactical fighter aircraft is the focus of this paper. The most promising set of aircraft sub-system configurations, based on both an energy integration analysis and aerodynamic performance, were first developed and detailed thermodynamic, geometric, physical, and aerodynamic models at both design and off-design were formulated and implemented. Conceptual, time, and physical decomposition were then applied to the synthesis/design and operational optimization of the aircraft system. The physical decomposition strategy used, called Iterative Local-Global Optimization (ILGO, was developed by Muñoz and von Spakovsky (2001a,b and has been applied to a number of complex stationary and transportation applications. This decomposition strategy is the first to successfully closely approach the theoretical condition of “thermoeconomic isolation” when applied to highly complex, highly dynamic non-linear systems.

  12. The Design and Optimization of Advanced Thermophotovoltaic Devices for Deep Space Applications Using a New Modeling Approach

    Science.gov (United States)

    Michael, Sherif; Canfield, L. T. Burt

    2007-02-01

    Thermophotovoltaic (TPV) cells hold great promise for lightweight, reliable energy conversion for deep space missions. A new method for developing a realistic model of any type of solar cell, with application to Thermophotovoltaic devices, is presented in this paper. Taking into account the high cost of research and experimentation involved with the development of advanced cells, we present here this novel methodology. An example model of an InGaP/GaAs/Ge multi-junction cell is prepared and is fully simulated. The major stages of the process are explained and the simulation results are compared to published experimental data. An example of cell parameters optimization is also presented. The flexibility of the proposed methodology is demonstrated and example results are shown throughout the whole process. One of the big problems for use of TPV devices in any space mission is heat removal. Currently, many TPV designs assume a low temperature radiator, which equates to large areas and masses. As an application to demonstrate the advantage of this approach. The Silvaco Virtual Wafer Fabrication Software is used as a tool to examine TPV optimization and performance at high temperatures in an attempt to reduce the mass cost associated with large radiators. Results are shown for InGaAs cells optimized to a 1300K black body at 350 K, 400 K, 450 K, and, 500 K.

  13. A Multi-Operator Simulation for Investigation of Distributed Air Traffic Management Concepts

    Science.gov (United States)

    Peters, Mark E.; Ballin, Mark G.; Sakosky, John S.

    2002-01-01

    This paper discusses the current development of an air traffic operations simulation that supports feasibility research for advanced air traffic management concepts. The Air Traffic Operations Simulation (ATOS) supports the research of future concepts that provide a much greater role for the flight crew in traffic management decision-making. ATOS provides representations of the future communications, navigation, and surveillance (CNS) infrastructure, a future flight deck systems architecture, and advanced crew interfaces. ATOS also provides a platform for the development of advanced flight guidance and decision support systems that may be required for autonomous operations.

  14. Simulation research and optimal design for digital power regulating system of China advanced research reactor

    International Nuclear Information System (INIS)

    Based on SimPort simulation platform of nuclear power plant, a simulation model for Digital Power Regulating System (DPRS) of China Advanced Research Reactor (CARR) was established. By simulating the transient state of DPRS using this model, the adjusting parameters for the digital PID controller were determined. According to the features of the driving mechanism, the effects of the driving accuracy of the control rod and the displacement delay between electromagnetic coil and armature upon system stability and the regulating performance were analyzed, furthermore, their stability limit values were obtained respectively. The research results of this paper have some engineering practical value. (authors)

  15. Optimizing the management of advanced non-small-cell lung cancer: a personal view

    OpenAIRE

    Vincent, M. D.

    2009-01-01

    The management of advanced non-small-cell lung cancer (a-nsclc) is currently undergoing one of its rare paradigm shifts. Just as the nihilism of the 1970s gave way to the empiricism of the 1980s and 1990s, so the current decade has seen the first truly rational therapies based on informed design. In addition, molecular markers and traditional parameters can now be combined to provide a framework of knowledge that will guide the application of not just the new therapies, but also the older one...

  16. Network Modeling and Energy-Efficiency Optimization for Advanced Machine-to-Machine Sensor Networks

    Directory of Open Access Journals (Sweden)

    Seoksoo Kim

    2012-11-01

    Full Text Available Wireless machine-to-machine sensor networks with multiple radio interfaces are expected to have several advantages, including high spatial scalability, low event detection latency, and low energy consumption. Here, we propose a network model design method involving network approximation and an optimized multi-tiered clustering algorithm that maximizes node lifespan by minimizing energy consumption in a non-uniformly distributed network. Simulation results show that the cluster scales and network parameters determined with the proposed method facilitate a more efficient performance compared to existing methods.

  17. Improved VMAT planning for head and neck tumors with an advanced optimization algorithm

    International Nuclear Information System (INIS)

    In this study, the ''Progressive Resolution Optimizer PRO3'' (Varian Medical Systems) is compared to the previous version PRO2'' with respect to its potential to improve dose sparing to the organs at risk (OAR) and dose coverage of the PTV for head and neck cancer patients. Materials and Methods For eight head and neck cancer patients, volumetric modulated arc therapy (VMAT) treatment plans were generated in this study. All cases have 2-3 phases and the total prescribed dose (PD) was 60-72 Gy in the PTV. The study is mainly focused on the phase 1 plans, which all have an identical PD of 54 Gy, and complex PTV structures with an overlap to the parotids. Optimization was performed based on planning objectives for the PTV according to ICRU83, and with minimal dose to spinal cord, and parotids outside PTV. In order to assess the quality of the optimization algorithms, an identical set of constraints was used for both, PRO2 and PRO3. The resulting treatment plans were investigated with respect to dose distribution based on the analysis of the dose volume histograms. Results For the phase 1 plans (PD = 54 Gy) the near maximum dose D2% of the spinal cord, could be minimized to 22±5 Gy with PRO3, as compared to 32±12 Gy with PRO2, averaged for all patients. The mean dose to the parotids was also lower in PRO3 plans compared to PRO2, but the differences were less pronounced. A PTV coverage of V95% = 97±1% could be reached with PRO3, as compared to 86±5% with PRO2. In clinical routine, these PRO2 plans would require modifications to obtain better PTV coverage at the cost of higher OAR doses. Conclusion A comparison between PRO3 and PRO2 optimization algorithms was performed for eight head and neck cancer patients. In general, the quality of VMAT plans for head and neck patients are improved with PRO3 as compared to PRO2. The dose to OARs can be reduced significantly, especially for the spinal cord. These reductions are achieved with better

  18. Improved VMAT planning for head and neck tumors with an advanced optimization algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Klippel, Norbert; Schmuecking, Michael; Terribilini, Dario; Geretschlaeger, Andreas; Aebersold, Daniel M.; Manser, Peter [Bern University Hospital - Inselspital (Switzerland). Div. of Medical Radiation Physics and Dept. of Radiation Oncology

    2015-07-01

    In this study, the ''Progressive Resolution Optimizer PRO3'' (Varian Medical Systems) is compared to the previous version PRO2'' with respect to its potential to improve dose sparing to the organs at risk (OAR) and dose coverage of the PTV for head and neck cancer patients. Materials and Methods For eight head and neck cancer patients, volumetric modulated arc therapy (VMAT) treatment plans were generated in this study. All cases have 2-3 phases and the total prescribed dose (PD) was 60-72 Gy in the PTV. The study is mainly focused on the phase 1 plans, which all have an identical PD of 54 Gy, and complex PTV structures with an overlap to the parotids. Optimization was performed based on planning objectives for the PTV according to ICRU83, and with minimal dose to spinal cord, and parotids outside PTV. In order to assess the quality of the optimization algorithms, an identical set of constraints was used for both, PRO2 and PRO3. The resulting treatment plans were investigated with respect to dose distribution based on the analysis of the dose volume histograms. Results For the phase 1 plans (PD = 54 Gy) the near maximum dose D{sub 2%} of the spinal cord, could be minimized to 22±5 Gy with PRO3, as compared to 32±12 Gy with PRO2, averaged for all patients. The mean dose to the parotids was also lower in PRO3 plans compared to PRO2, but the differences were less pronounced. A PTV coverage of V{sub 95%} = 97±1% could be reached with PRO3, as compared to 86±5% with PRO2. In clinical routine, these PRO2 plans would require modifications to obtain better PTV coverage at the cost of higher OAR doses. Conclusion A comparison between PRO3 and PRO2 optimization algorithms was performed for eight head and neck cancer patients. In general, the quality of VMAT plans for head and neck patients are improved with PRO3 as compared to PRO2. The dose to OARs can be reduced significantly, especially for the spinal cord. These reductions are achieved

  19. Decomposition with thermoeconomic isolation applied to the optimal synthesis/design and operation of an advanced tactical aircraft system

    Energy Technology Data Exchange (ETDEWEB)

    Rancruel, Diego F. [Center for Energy Systems Research, Department of Mechanical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060 (United States); Spakovsky, Michael R. von [Center for Energy Systems Research, Department of Mechanical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060 (United States)]. E-mail: vonspako@vt.edu

    2006-12-15

    A decomposition methodology based on the concept of 'thermoeconomic isolation' and applied to the synthesis/design and operational optimization of an advanced tactical fighter aircraft is the focus of this paper. The total system is composed of six sub-systems of which five participate with degrees of freedom (493) in the optimization. They are the propulsion sub-system (PS), the environmental control sub-system (ECS), the fuel loop subsystem (FLS), the vapor compression and Polyalphaolefin (PAO) loops sub-system (VC/PAOS), and the airframe sub-system (AFS). The sixth subsystem comprises the expendable and permanent payloads as well as the equipment group. For each of the first five, detailed thermodynamic, geometric, physical, and aerodynamic models at both design and off-design were formulated and implemented. The most promising set of aircraft sub-system and system configurations were then determined based on both an energy integration and aerodynamic performance analysis at each stage of the mission (including the transient ones). Conceptual, time, and physical decomposition were subsequently applied to the synthesis/design and operational optimization of these aircraft configurations as well as to the highly dynamic process of heat generation and dissipation internal to the subsystems. The physical decomposition strategy used (i.e. Iterative Local-Global Optimization-ILGO) is the first to successfully closely approach the theoretical condition of 'thermoeconomic isolation' when applied to highly complex, highly dynamic non-linear systems. Developed at our Center for Energy Systems research, it has been effectively applied to a number of complex stationary and transportation applications.

  20. Decomposition with thermoeconomic isolation applied to the optimal synthesis/design and operation of an advanced tactical aircraft system

    International Nuclear Information System (INIS)

    A decomposition methodology based on the concept of 'thermoeconomic isolation' and applied to the synthesis/design and operational optimization of an advanced tactical fighter aircraft is the focus of this paper. The total system is composed of six sub-systems of which five participate with degrees of freedom (493) in the optimization. They are the propulsion sub-system (PS), the environmental control sub-system (ECS), the fuel loop subsystem (FLS), the vapor compression and Polyalphaolefin (PAO) loops sub-system (VC/PAOS), and the airframe sub-system (AFS). The sixth subsystem comprises the expendable and permanent payloads as well as the equipment group. For each of the first five, detailed thermodynamic, geometric, physical, and aerodynamic models at both design and off-design were formulated and implemented. The most promising set of aircraft sub-system and system configurations were then determined based on both an energy integration and aerodynamic performance analysis at each stage of the mission (including the transient ones). Conceptual, time, and physical decomposition were subsequently applied to the synthesis/design and operational optimization of these aircraft configurations as well as to the highly dynamic process of heat generation and dissipation internal to the subsystems. The physical decomposition strategy used (i.e. Iterative Local-Global Optimization-ILGO) is the first to successfully closely approach the theoretical condition of 'thermoeconomic isolation' when applied to highly complex, highly dynamic non-linear systems. Developed at our Center for Energy Systems research, it has been effectively applied to a number of complex stationary and transportation applications

  1. Advances in the use of odour as forensic evidence through optimizing and standardizing instruments and canines.

    Science.gov (United States)

    Furton, Kenneth G; Caraballo, Norma Iris; Cerreta, Michelle M; Holness, Howard K

    2015-08-01

    This paper explores the advances made in identifying trace amounts of volatile organic compounds (VOCs) that originate from forensic specimens, such as drugs, explosives, live human scent and the scent of death, as well as the probative value for detecting such odours. The ability to locate and identify the VOCs liberated from or left by forensic substances is of increasing importance to criminal investigations as it can indicate the presence of contraband and/or associate an individual to a particular location or object. Although instruments have improved significantly in recent decades-with sensitivities now rivalling that of biological detectors-it is widely recognized that canines are generally still more superior for the detection of odourants due to their speed, versatility, ruggedness and discriminating power. Through advancements in the detection of VOCs, as well as increased standardization efforts for instruments and canines, the reliability of odour as evidence has continuously improved and is likely to continue to do so. Moreover, several legal cases in which this novel form of evidence has been accepted into US courts of law are discussed. As the development and implementation of best practice guidelines for canines and instruments increase, their reliability in detecting VOCs of interest should continue to improve, expanding the use of odour as an acceptable form of forensic evidence. PMID:26101287

  2. Advanced Algorithm for Optimizing the Deployment Cost of Passive Optical Networks

    Directory of Open Access Journals (Sweden)

    Pavel Lafata

    2013-01-01

    Full Text Available The deployment of passive optical networks (PONs is slow today, especially in Europe, because completely new optical infrastructures are necessary to be installed in the last-mile segments of access networks, which is always very expensive process. One of the possibilities is to design economically effective topologies and to optimize the deployment cost. This article describes the method leading to evaluate an algorithm for designing suboptimal economic solutions and topologies for PONs by focusing on optimization of constructional length of distribution networks. While the typical PON topologies are star topologies or tree-star topologies, the first part of this article introduces new sub algorithm for estimating the minimum star topology. The next section brings the evaluation of two sub algorithms for solving minimum constructional length problems. Finally, all these parts will be merged into a complex algorithm by using clusterization technique to solve optimum topologies. However, the current version of presented algorithm is purely based on mathematical theories and was implemented in Matlab environment. Therefore, it is able to design only theoretical optimum topologies without taking external conditions and real limitations into account. These real conditions will be further implemented in the future, so the algorithm could be also used for practical applications.

  3. OPTIMIZATION OF MUD HAMMER DRILLING PERFORMANCE--A PROGRAM TO BENCHMARK THE VIABILITY OF ADVANCED MUD HAMMER DRILLING

    Energy Technology Data Exchange (ETDEWEB)

    Arnis Judzis

    2004-07-01

    This document details the progress to date on the ''OPTIMIZATION OF MUD HAMMER DRILLING PERFORMANCE--A PROGRAM TO BENCHMARK THE VIABILITY OF ADVANCED MUD HAMMER DRILLING'' contract for the quarter starting April 2004 through June 2004. The DOE and TerraTek continue to wait for Novatek on the optimization portion of the testing program (they are completely rebuilding their fluid hammer). The latest indication is that the Novatek tool would be ready for retesting only 4Q 2004 or later. Smith International's hammer was tested in April of 2004 (2Q 2004 report). Accomplishments included the following: (1) TerraTek re-tested the ''optimized'' fluid hammer provided by Smith International during April 2004. Many improvements in mud hammer rates of penetration were noted over Phase 1 benchmark testing from November 2002. (2) Shell Exploration and Production in The Hague was briefed on various drilling performance projects including Task 8 ''Cutter Impact Testing''. Shell interest and willingness to assist in the test matrix as an Industry Advisor is appreciated. (3) TerraTek participated in a DOE/NETL Review meeting at Morgantown on April 15, 2004. The discussions were very helpful and a program related to the Mud Hammer optimization project was noted--Terralog modeling work on percussion tools. (4) Terralog's Dr. Gang Han witnessed some of the full-scale optimization testing of the Smith International hammer in order to familiarize him with downhole tools. TerraTek recommends that modeling first start with single cutters/inserts and progress in complexity. (5) The final equipment problem on the impact testing task was resolved through the acquisition of a high data rate laser based displacement instrument. (6) TerraTek provided Novatek much engineering support for the future re-testing of their optimized tool. Work was conducted on slip ring [electrical] specifications and tool collar sealing in the

  4. Emergent traffic jams

    CERN Document Server

    Nagel, K; Nagel, Kai; Paczuski, Maya

    1995-01-01

    We study a single-lane traffic model that is based on human driving behavior. The outflow from a traffic jam self-organizes to a critical state of maximum throughput. Small perturbations of the outflow far downstream create emergent traffic jams with a power law distribution P(t) \\sim t^{-3/2} of lifetimes, t. On varying the vehicle density in a closed system, this critical state separates lamellar and jammed regimes, and exhibits 1/f noise in the power spectrum. Using random walk arguments, in conjunction with a cascade equation, we develop a phenomenological theory that predicts the critical exponents for this transition and explains the self-organizing behavior. These predictions are consistent with all of our numerical results.

  5. The optimized li advanced tokamak scenario with high bootstrap current fraction

    International Nuclear Information System (INIS)

    Equilibrium and stability analyses have identified a class of tokamak configurations with conventional safety factor profiles (q0∼qmin approx-gt 1) at moderately high li(li∼1.0), and high normalized β(βN∼3.5 - 4.0), that are stable to the ideal n=1 kink without the requirement of wall stabilization. In contrast to previously identified high li, high βN equilibria, these configurations have high bootstrap current fractions (fBS∼50%- 70%); they require only modest central current drive for maintaining steady state and are therefore compatible with advanced tokamak (AT) operation. Strong plasma shaping is crucial for achieving the high β and high bootstrap fraction simultaneously. copyright 1999 American Institute of Physics

  6. Simulation research and optimal design for digital power regulating system of China advanced research reactor

    International Nuclear Information System (INIS)

    Based on SimPort simulation platform of nuclear power plant, a simulation model for Digital Power Regulating System (DPRS) of China Advanced Research Reactor (CARR) was established. The transient state of DPRS was simulation studied using this model. According to the characteristics of the driving mechanism of the control rods, the effects of the driving precision of the control rod and its displacement delay upon the system stability were analyzed. Considering the process requirements of CARR and the function characteristic of DRPS, the adjusting parameters for the digital PID controller and the stability limits of the driving mechanism of the control rods were obtained. The sampling period of the digital PID controller is 100 ms and its proportion gain is 300. The stability limit of the driving precision of the control rod is 0.4 mm. The stability limit of displacement delay between electromagnetic coil and armature is 6.0 mm. (authors)

  7. Optimization of stabilized leachate treatment using ozone/persulfate in the advanced oxidation process

    International Nuclear Information System (INIS)

    Highlights: ► Ozone and persulfate reagent (O3/S2O82-) was used to treat stabilized leachate. ► Central composite design (CCD) with response surface methodology (RSM) was applied. ► Operating variables including ozone and persulfate dosage, pH variance, and reaction time. ► Optimum removal of COD, color, and NH3–N was 72%, 96%, and 76%, respectively. ► A good value of ozone consumption (OC) obtained with 0.60 (kg O3/kg COD). - Abstract: The objective of this study was to investigate the performance of employing persulfate reagent in the advanced oxidation of ozone to treat stabilized landfill leachate in an ozone reactor. A central composite design (CCD) with response surface methodology (RSM) was applied to evaluate the relationships between operating variables, such as ozone and persulfate dosages, pH, and reaction time, to identify the optimum operating conditions. Quadratic models for the following four responses proved to be significant with very low probabilities (3–N, and ozone consumption (OC). The obtained optimum conditions included a reaction time of 210 min, 30 g/m3 ozone, 1 g/1 g COD0/S2O82- ratio, and pH 10. The experimental results were corresponded well with predicted models (COD, color, and NH3–N removal rates of 72%, 96%, and 76%, respectively, and 0.60 (kg O3/kg COD OC). The results obtained in the stabilized leachate treatment were compared with those from other treatment processes, such as ozone only and persulfate S2O82- only, to evaluate its effectiveness. The combined method (i.e., O3/S2O82-) achieved higher removal efficiencies for COD, color, and NH3–N compared with other studied applications. Furthermore, the new method is more efficient than ozone/Fenton in advanced oxidation process in the treatment of the same studied leachate

  8. Methodology for the Integration of Safety in the Optimization of the Advanced Reactors Design

    International Nuclear Information System (INIS)

    In this work a new methodology has been developed and implemented for taking into account the safety levels of the reactor in a design optimization process, by using Design Maps.They represent a new technique for comparing critical variables in case an accidental sequenced happened, with limit values set by the design criteria.So a good balance is achieved, without allowing the economic performance search to cause a too risky reactor, and guaranteeing the competitiveness of it in spite of the safety costs.Up to the moment, there is no design tool able to accomplish this task in an integrated way.A computational tool based on this methodology has been implemented.These tool specially programmed routines allow carrying out the mentioned tasks

  9. Joint inversion of TEM and DC in roadway advanced detection based on particle swarm optimization

    Science.gov (United States)

    Cheng, Jiulong; Li, Fei; Peng, Suping; Sun, Xiaoyun; Zheng, Jing; Jia, Jizhe

    2015-12-01

    Transient electromagnetic method (TEM)and direct current method (DC)are two key widely applied methods for practical roadway detection, but both have their limitations. To take the advantage of each method, a synchronous nonlinear joint inversion method is proposed based on TEM and DC by using particle swarm optimization (PSO)algorithm. Firstly, a model with double low resistance anomaly and interference is constructed to test the performance of the method. Then the independent inversion and joint inversion are calculated by using the model built above. It is demonstrated that the joint inversion helped in improving the interpretation of the data to get better results. It is because that the suppression of interference and separation of the resistivity anomalies ahead and the back of the roadway working face using the proposed method. Finally, the proposed method was successfully used in a coalmine in Huainan coalfield in east China to demonstrate its practical usefulness.

  10. Design of a fuel recharge for a BWR using advanced optimization systems

    International Nuclear Information System (INIS)

    The fuel recharge design for a BWR reactor it was carried out, which includes the design of four fuel cells to form an assembly, the accommodation design of fresh and partially consumed assemblies and the control bars pattern design to use along an operation cycle. The three stages were approached as optimization problems using different computational tools, each one of those includes an objective function to measure quantitatively the evolution of the different candidate solutions. With the tool used in the fuel cells design that makes use of the tabu search technique its were obtained cells that showed to be lightly more reactive that other similar taken as reference. With the four designed cells it was formed a fuel assembly that turn out to have an average enrichment lightly smaller to the one of another assembly similar taken as reference. In the recharge pattern design it was used another optimization tool, also based on tabu search to obtain the accommodation of 108 fresh fuels and 336 partially consumed, fulfilling the conditions imposed to operate with the core strategies with control cells (CCC) and of low leakage. A Haling calculation reported that with the obtained accommodation it was achievement to increase in 8% the cycle length with regard to the one obtained using a similar reference pattern. In the design of the control bars patterns it was used a tool based on the use of the genetic algorithms to obtain the placement patterns of the control bars along an operation cycle. The search tool only uses the bars of the A2 sequence and it makes use of the 1/8 symmetry of the core, with that the number of used control bars it decreases at 5. Also the use of control bars in intermediate positions is also avoided. With the obtained patterns a cycle length is obtained that is lightly bigger to the reported value in a Haling calculation. (Author)

  11. A study on optimization of hybrid drive train using Advanced Vehicle Simulator (ADVISOR)

    Science.gov (United States)

    Same, Adam; Stipe, Alex; Grossman, David; Park, Jae Wan

    This study investigates the advantages and disadvantages of three hybrid drive train configurations: series, parallel, and "through-the-ground" parallel. Power flow simulations are conducted with the MATLAB/Simulink-based software ADVISOR. These simulations are then applied in an application for the UC Davis SAE Formula Hybrid vehicle. ADVISOR performs simulation calculations for vehicle position using a combined backward/forward method. These simulations are used to study how efficiency and agility are affected by the motor, fuel converter, and hybrid configuration. Three different vehicle models are developed to optimize the drive train of a vehicle for three stages of the SAE Formula Hybrid competition: autocross, endurance, and acceleration. Input cycles are created based on rough estimates of track geometry. The output from these ADVISOR simulations is a series of plots of velocity profile and energy storage State of Charge that provide a good estimate of how the Formula Hybrid vehicle will perform on the given course. The most noticeable discrepancy between the input cycle and the actual velocity profile of the vehicle occurs during deceleration. A weighted ranking system is developed to organize the simulation results and to determine the best drive train configuration for the Formula Hybrid vehicle. Results show that the through-the-ground parallel configuration with front-mounted motors achieves an optimal balance of efficiency, simplicity, and cost. ADVISOR is proven to be a useful tool for vehicle power train design for the SAE Formula Hybrid competition. This vehicle model based on ADVISOR simulation is applicable to various studies concerning performance and efficiency of hybrid drive trains.

  12. Optimal fares and capacity decisions for crowded public transport systems

    OpenAIRE

    De Palma, André; Lindsey, Robin; Monchambert, Guillaume

    2015-01-01

    International audience There is a large operations research literature on public transit system design. An extensive economic literature has also developed on public transit capacity investments, service frequency, and optimal pricing and subsidy policy. These two branches of literature have made significant advances in understanding public transit systems. However, in contrast to the literature on automobile traffic congestion, most of the studies have employed static models that cannot a...

  13. Traffic signals - alternative method for emissions reduction; Liikennevaloillako paeaestoet alas

    Energy Technology Data Exchange (ETDEWEB)

    Niittymaeki, J. [Helsinki Univ. of Technology, Espoo (Finland)

    2001-07-01

    Traffic signalling is a process, which adapts to the prevailing traffic. The objective of traffic signalling is to direct traffic as safely as possible through a road junction. Other objectives are to maximize the road capacity, to clarify the traffic, and to effect the selection of routs. The target of design and timing of traffic signalling is to minimize the delays of the traffic. However, traffic signalling increases the emissions and fuel consumption. Traditionally the traffic adaptive control has been arranged on the basis of the extension principle, which means the extension of the green light as long as there is demand for the signal, however, only to a set maximum time. In practice the systems seeks an adequate distance in the traffic for cutting off the green light. New methods, such as mathematical optimization, fuzzy logic, neural networks and generic algorithms have been included traffic signalling. These new methods have proven to be 10-20% more efficient than the old ones. Results of the researches have shown that it is possible to achieve significant savings in social economy, including savings in fuels consumption and environmental impacts of the traffic, by development/renovation of traffic signalling. This article reviews the studies carried out in Finland on traffic signalling. A typical driving process through a signalized road junction: deceleration, idle running, acceleration and steady driving. The emissions of these phases differ from each other. Gasoline-fueled cars equipped with catalyst produces significantly more CO during idle running than in the other phases, and the HC content is highest during deceleration. On the other hand NO{sub x} formation is highest during acceleration. Formation of CO, HC and aldehydes is lowest during steady driving, and the formation of NO{sub x} during deceleration. CO and NO{sub x} emissions of diesel engines are highest during acceleration, and HC emissions during idle running. Total emissions of diesel

  14. Two dimensional mixed traffic flow considering the transit traffic

    Directory of Open Access Journals (Sweden)

    Lingjiang Kong

    2012-12-01

    Full Text Available Based on the two-dimension cellular automaton traffic flow model (BML model, a mixed traffic flow model for urban traffic considering the transit traffic is established in this paper by using the Don't block the box rules. We have investigated the influences of the transit traffic ratio, and found that, in most cases, the urban traffic flow exhibited jam phase. Moreover, focusing on the traffic lights cycle, it is found that the average flow has the periodic fluctuation phenomenon, and we have explained this periodical oscillation change under different boundary conditions. The comparison to practical measured data shows that our stimulation results are accordant with the changes of real traffic flow, which confirms the accuracy and rationality of our model.

  15. Traffic Light Detection

    DEFF Research Database (Denmark)

    Philipsen, Mark Philip; Jensen, Morten Bornø; Møgelmose, Andreas;

    2015-01-01

    Traffic light recognition (TLR) is an integral part of any intelligent vehicle, which must function in the existing infrastructure. Pedestrian and sign detection have recently seen great improvements due to the introduction of learning based detectors using integral channel features. A similar push...... database is collected based on footage from US roads. The database consists of both test and training data, totaling 46,418 frames and 112,971 annotated traffic lights, captured in continuous sequences under a varying light and weather conditions. The learning based detector achieves an AUC of 0.4 and 0...

  16. Traffic improvement and transportation pollution control in Xiamen

    Energy Technology Data Exchange (ETDEWEB)

    Dongxing Yuan; Zilin, Wu

    1996-12-31

    in this paper, the urban traffic improvement and transportation control in Xiamen are highlighted. Xiamen is a port city and an economical special zone of China. As the economy grows, the transportation is developing dramatically and becoming the key for further economic development. The air quality is threatened by the rapid growth of the vehicles in the city. The most urgent task in improving urban traffic is to establish a sound traffic system. The municipal government takes great effort to improve the traffic condition, as well as to reduce green house gases and protect air environment. Some management and technical measures are carried out. Those management measures are mainly as follows: (1) systematic planning of the city arrangement and city functional division, and integrated planning of the urban roads system, (2) putting great emphasis on tail gas monitoring and management, and (3) establishing optimized utilization of motor vehicles. Those included in the main technical measures are (1) making the roads clear, (2) enlarging traffic capacity, and (3) developing the public transport. The most urgent task in improving urban traffic is to establish a sound traffic system. The city municipal government and Transportation Management Bureau plan to make a series of reforms to improve the urban traffic condition, such as building high quality road around the city, reducing the number of one way roads and replacing gasoline buses with electric buses. An optimized traffic system of Xiamen, taking public transport as the main means, is the key to meet the needs of both traffic improvement and urban transportation pollution control.

  17. Network Traffic Obfuscation and Automated Internet Censorship

    OpenAIRE

    Dixon, Lucas; Ristenpart, Thomas; Shrimpton, Thomas

    2016-01-01

    Internet censors seek ways to identify and block internet access to information they deem objectionable. Increasingly, censors deploy advanced networking tools such as deep-packet inspection (DPI) to identify such connections. In response, activists and academic researchers have developed and deployed network traffic obfuscation mechanisms. These apply specialized cryptographic tools to attempt to hide from DPI the true nature and content of connections. In this survey, we give an overview of...

  18. En-Route Vehicular Traffic Optimization

    OpenAIRE

    Saravanan M; Ashwin Kumar M

    2015-01-01

    The pathways of information are changing, the physical world itself is becoming a type of information system. In what’s called the Internet of Things (IoT), sensors and actuators embedded in physical objects—from roadways to pacemakers—are linked through wired and wireless networks, often using the same Internet Protocol (IP) that connects the Internet. When objects can both sense the environment and communicate, they become tools for understanding complexity and responding to it swiftly. The...

  19. Optimizing the beta limit in DIII-D advanced tokamak discharges

    International Nuclear Information System (INIS)

    Results are presented from comparisons of modeling and experiment in studies to assess the best choice of safety factor (q) profile, pressure profile and discharge shape for high beta, steady-state, noninductive advanced tokamak operation. This is motivated by the need for high qminβN to maximize the self-driven bootstrap current while maintaining high toroidal beta to increase fusion gain. Experiment and theory both show that increases in the achievable normalized beta (βN) can be obtained through broadening of the pressure profile and use of a symmetric double-null divertor shape. The general trend is for βN to decrease as the minimum q value (qmin) increases, but with a broadened pressure profile, βN = 4 is obtained with qmin ∼ 2 and qminβN increases with qmin. Modeling of equilibria with near 100% bootstrap current indicates that operation with βN ∼ 5 should be possible with a sufficiently broad pressure profile. (author)

  20. A Modified Time Advancement Algorithm for Optimizing Channel Flow Analysis in Direct Numerical Simulation Method

    Directory of Open Access Journals (Sweden)

    E. Rajabi

    2014-01-01

    Full Text Available In this research a direct numerical simulation (DNS of turbulent flow is performed in a geometrically standard case like plane channel flow. Pseudo spectral (PS method is used due to geometry specifications and very high accuracy achieved despite relatively few grid points. A variable time-stepping algorithm is proposed which may reduce requirement of computational cost in simulation of such wall-bounded flow. Channel flow analysis is performed with both constant and varied time-step for 128 × 65×128 grid points. The time advancement is carried out by implicit third-order backward differentiation scheme for linear terms and explicit forward Euler for nonlinear convection term. PS method is used in Cartesian coordinates with Chebychev polynomial expansion in normal direction for one non-periodic boundary condition. Also Fourier series is employed in stream-wise and span-wise directions for two periodic boundary conditions. The friction Reynolds number is about Reτ=175 based on a friction velocity and channel half width. Standard common rotational form was chosen for discritization of nonlinear convective term of Navier-Stocks equation. The comparison is made between turbulent quantities such as the turbulent statistics, Reynolds stress, wall shear velocity, standard deviation of (u and total normalized energy of instantaneous velocities in both time-discretization methods. The results show that if final decision rests on economics, the proposed variable time-stepping algorithm will be proper choice which satisfies the accuracy and reduces the computational cost.

  1. CPV module design optimization for advanced multi-junction solar cell concepts

    Science.gov (United States)

    Steiner, Marc; Kiefel, Peter; Siefer, Gerald; Wiesenfarth, Maike; Dimroth, Frank; Krause, Rainer; Gombert, Andreas; Bett, Andreas W.

    2015-09-01

    A network model for multi-junction solar cells has been combined with ray tracing and finite element simulations of a Fresnel lens in order to interpret experimentally derived measurement results. This combined model reveals a good agreement between simulation and measurement for advanced four-junction solar cells under a Fresnel lens when the cell-to-lens distance was varied. Thus, the effect of fill factor drop caused by distributed series resistance losses due to chromatic aberration is well described by this model. Eventually, this model is used to calculate I-V characteristics of a four-junction cell, as well as of a upright metamorphic and lattice-matched triple-junction solar cell under the illumination profile of a Fresnel lens. A significant fill factor drop at distinct cell-to-lens distances was found for all three investigated solar cell types. In this work we discuss how this fill factor drop can be avoided. It is shown that already a halving of the sheet resistance within one of the lateral conduction layer in the solar cell increases the module efficiency significantly.

  2. Website Optimization

    CERN Document Server

    King, Andrew

    2008-01-01

    Remember when an optimized website was one that merely didn't take all day to appear? Times have changed. Today, website optimization can spell the difference between enterprise success and failure, and it takes a lot more know-how to achieve success. This book is a comprehensive guide to the tips, techniques, secrets, standards, and methods of website optimization. From increasing site traffic to maximizing leads, from revving up responsiveness to increasing navigability, from prospect retention to closing more sales, the world of 21st century website optimization is explored, exemplified a

  3. A Structural Model of Traffic Congestion

    OpenAIRE

    Verhoef, Erik T.; Rouwendal, Jan

    2001-01-01

    Conventional economic models of traffic congestion assume that therelation between road use and speed is a technical one. In this paper wederive the speed-flow relationship from more fundamental considerationsconcerning driving behaviour. We develop a structural model in which driverschoose their own optimal speed, by trading off various cost aspects of making atrip: time costs, expected accident costs and fuel costs. Since the optimalspeed depends on the presence of other drivers on the road...

  4. Characterization, performance and optimization of PVDF as a piezoelectric film for advanced space mirror concepts.

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Gary D.; Assink, Roger Alan; Dargaville, Tim Richard; Chaplya, Pavel Mikhail; Clough, Roger Lee; Elliott, Julie M.; Martin, Jeffrey W.; Mowery, Daniel Michael; Celina, Mathew Christopher

    2005-11-01

    Piezoelectric polymers based on polyvinylidene fluoride (PVDF) are of interest for large aperture space-based telescopes as adaptive or smart materials. Dimensional adjustments of adaptive polymer films depend on controlled charge deposition. Predicting their long-term performance requires a detailed understanding of the piezoelectric material features, expected to suffer due to space environmental degradation. Hence, the degradation and performance of PVDF and its copolymers under various stress environments expected in low Earth orbit has been reviewed and investigated. Various experiments were conducted to expose these polymers to elevated temperature, vacuum UV, {gamma}-radiation and atomic oxygen. The resulting degradative processes were evaluated. The overall materials performance is governed by a combination of chemical and physical degradation processes. Molecular changes are primarily induced via radiative damage, and physical damage from temperature and atomic oxygen exposure is evident as depoling, loss of orientation and surface erosion. The effects of combined vacuum UV radiation and atomic oxygen resulted in expected surface erosion and pitting rates that determine the lifetime of thin films. Interestingly, the piezo responsiveness in the underlying bulk material remained largely unchanged. This study has delivered a comprehensive framework for material properties and degradation sensitivities with variations in individual polymer performances clearly apparent. The results provide guidance for material selection, qualification, optimization strategies, feedback for manufacturing and processing, or alternative materials. Further material qualification should be conducted via experiments under actual space conditions.

  5. Fifty years of chasing lizards: new insights advance optimal escape theory.

    Science.gov (United States)

    Samia, Diogo S M; Blumstein, Daniel T; Stankowich, Theodore; Cooper, William E

    2016-05-01

    Systematic reviews and meta-analyses often examine data from diverse taxa to identify general patterns of effect sizes. Meta-analyses that focus on identifying generalisations in a single taxon are also valuable because species in a taxon are more likely to share similar unique constraints. We conducted a comprehensive phylogenetic meta-analysis of flight initiation distance in lizards. Flight initiation distance (FID) is a common metric used to quantify risk-taking and has previously been shown to reflect adaptive decision-making. The past decade has seen an explosion of studies focused on quantifying FID in lizards, and, because lizards occur in a wide range of habitats, are ecologically diverse, and are typically smaller and differ physiologically from the better studied mammals and birds, they are worthy of detailed examination. We found that variables that reflect the costs or benefits of flight (being engaged in social interactions, having food available) as well as certain predator effects (predator size and approach speed) had large effects on FID in the directions predicted by optimal escape theory. Variables that were associated with morphology (with the exception of crypsis) and physiology had relatively small effects, whereas habitat selection factors typically had moderate to large effect sizes. Lizards, like other taxa, are very sensitive to the costs of flight. PMID:25620002

  6. Road Traffic Control Based on Genetic Algorithm for Reducing Traffic Congestion

    Science.gov (United States)

    Shigehiro, Yuji; Miyakawa, Takuya; Masuda, Tatsuya

    In this paper, we propose a road traffic control method for reducing traffic congestion with genetic algorithm. In the not too distant future, the system which controls the routes of all vehicles in a certain area must be realized. The system should optimize the routes of all vehicles, however the solution space of this problem is enormous. Therefore we apply the genetic algorithm to this problem, by encoding the route of all vehicles to a fixed length chromosome. To improve the search performance, a new genetic operator called “path shortening” is also designed. The effectiveness of the proposed method is shown by the experiment.

  7. Optimization and control methods in industrial engineering and construction

    CERN Document Server

    Wang, Xiangyu

    2014-01-01

    This book presents recent advances in optimization and control methods with applications to industrial engineering and construction management. It consists of 15 chapters authored by recognized experts in a variety of fields including control and operation research, industrial engineering, and project management. Topics include numerical methods in unconstrained optimization, robust optimal control problems, set splitting problems, optimum confidence interval analysis, a monitoring networks optimization survey, distributed fault detection, nonferrous industrial optimization approaches, neural networks in traffic flows, economic scheduling of CCHP systems, a project scheduling optimization survey, lean and agile construction project management, practical construction projects in Hong Kong, dynamic project management, production control in PC4P, and target contracts optimization.   The book offers a valuable reference work for scientists, engineers, researchers and practitioners in industrial engineering and c...

  8. Predictive modelling of running and dwell times in railway traffic

    OpenAIRE

    Kecman, P.; Goverde, R.M.P.

    2015-01-01

    Accurate estimation of running and dwell times is important for all levels of planning and control of railway traffic. The availability of historical track occupation data with a high degree of granularity inspired a data-driven approach for estimating these process times. In this paper we present and compare the accuracy of several approaches to model running and dwell times in railway traffic. Three global predictive model approaches are presented based on advanced statistical learning tech...

  9. Traffic Light Detection

    DEFF Research Database (Denmark)

    Philipsen, Mark Philip; Jensen, Morten Bornø; Møgelmose, Andreas; Moeslund, Thomas B.; Trivedi, Mohan M.

    database is collected based on footage from US roads. The database consists of both test and training data, totaling 46,418 frames and 112,971 annotated traffic lights, captured in continuous sequences under a varying light and weather conditions. The learning based detector achieves an AUC of 0.4 and 0...

  10. Advanced CANDU reactor: an optimized energy source of oil sands application

    International Nuclear Information System (INIS)

    Atomic Energy of Canada Limited (AECL) is developing the ACR-700TM (Advanced CANDU Reactor-700TM) to meet customer needs for reduced capital cost, shorter construction schedule, high capacity factor while retaining the benefits of the CANDU experience base. The ACR-700 is based on the concept of CANDU horizontal fuel channels surrounded by heavy water moderator. The major innovation of this design is the use of slightly enriched uranium fuel in a CANFLEX bundle that is cooled by light water. This ensures: higher main steam pressures and temperatures providing higher thermal efficiency; a compact and simpler reactor design with reduced capital costs and shorter construction schedules; and reduced heavy water inventory compared to existing CANDU reactors. ACR-700 is not only a technically advanced and cost effective solution for electricity generating utilities, but also a low-cost, long-life and sustainable steam source for increasing Alberta's Oil Sand production rates. Currently practiced commercial surface mining and extraction of Oil Sand resources has been well established over the last three decades. But a majority of the available resources are somewhat deeper underground require in-situ extraction. Economic removal of such underground resources is now possible through the Steam Assisted Gravity Drainage (SAGD) process developed and proto-type tested in-site. SAGD requires the injection of large quantities of high-pressure steam into horizontal wells to form reduced viscosity bitumen and condensate mixture that is then collected at the surface. This paper describes joint AECL studies with CERI (Canadian Energy Research Institute) for the ACR, supplying both electricity and medium-pressure steam to an oil sands facility. The extensive oil sands deposits in northern Alberta are a very large energy resource. Currently, 30% of Canda's oil production is from the oil sands and this is expected to expand greatly over the coming decade. The bitumen deposits in the

  11. Performance Optimization of Storable Bipropellant Engines to Fully Exploit Advanced Material Technologies

    Science.gov (United States)

    Miller, Scott; Henderson, Scott; Portz, Ron; Lu, Frank; Wilson, Kim; Krismer, David; Alexander, Leslie; Chapman, Jack; England, Chris

    2007-01-01

    This paper summarizes the work performed to dale on the NASA Cycle 3A Advanced Chemical Propulsion Technology Program. The primary goals of the program are to design, fabricate, and test high performance bipropellant engines using iridium/rhenium chamber technology to obtain 335 seconds specific impulse with nitrogen tetroxide/hydrazine propellants and 330 seconds specific impulse with nitrogen tetroxide/monomethylhydrazine propellants. Aerojet has successfully completed the Base Period of this program, wherein (1) mission and system studies have been performed to verify system performance benefits and to determine engine physical and operating parameters, (2) preliminary chamber and nozzle designs have been completed and a chamber supplier has been downselected, (3) high temperature, high pressure off-nominal hot fire testing of an existing state-of-the-art high performance bipropellant engine has been completed, and (4) thermal and performance data from the engine test have been correlated with new thermal models to enable design of the new engine injector and injector/chamber interface. In the next phase of the program, Aerojet will complete design, fabrication, and test of the nitrogen tetroxide/hydrazine engine to demonstrate 335 seconds specific impulse, and also investigate improved technologies for iridium/rhenium chamber fabrication. Achievement of the NRA goals will significantly benefit NASA interplanetary missions and other government and commercial opportunities by enabling reduced launch weight and/or increased payload. At the conclusion of the program, the objective is to have an engine ready for final design and qualification for a specific science mission or commercial application. The program also constitutes a stepping stone to future, development, such as higher pressure pump-fed in-space storable engines.

  12. Traffic flow modeling: a Genealogy

    OpenAIRE

    Van Wageningen-Kessels, F.L.M.; Hoogendoorn, S.P.; Vuik, C.; Lint, van J. W. C.

    2014-01-01

    80 years ago, Bruce Greenshields presented the first traffic flow model at the Annual Meeting of the Highway Research Board. Since then, many models and simulation tools have been developed. We show a model tree with four families of traffic flow models, all descending from Greenshields' model. The tree shows the historical development of traffic flow modeling and the relations between models. Based on the tree we discuss the main trends and future developments in traffic flow modeling and si...

  13. Virtualized Traffic at Metropolitan Scales

    OpenAIRE

    Wilkie, David; Sewall, Jason; Li, Weizi; Lin, Ming C.

    2015-01-01

    Few phenomena are more ubiquitous than traffic in urban scenes, and few are more significant economically, socially, or environmentally. Many virtual-reality applications and systems, including virtual globes and immersive multi-player worlds that are often set in a large-scale modern or futuristic setting, feature traffic systems. Virtual-reality models can also aid in addressing the challenges of real-world traffic – the ever-present gridlock and congestion in cities worldwide: traffic engi...

  14. Road Traffic Accidents in Kazakhstan

    OpenAIRE

    Alma Aubakirova; Alibek Kossumov; Nurbek Igissinov

    2013-01-01

    Background: The article provides the analysis of death rates in road traffic accidents in Kazakhstan from 2004 to 2010 and explores the use of sanitary aviation. Methods: Data of fatalities caused by road traffic accidents were collected and analysed. Descriptive and analytical methods of epidemiology and biomedical statistics were applied. Results: Totaly 27,003 people died as a result of road traffic accidents in this period. The death rate for the total population due to road traffic accid...

  15. Coordination of traffic lights evaluation

    OpenAIRE

    Ordeig Vila, Enric

    2012-01-01

    This case study consists in the evaluation of the Kaunas city traffic speed taking into consideration that traffic lights were coordinated. Kaunas suffers from high traffic intensity and, as a consequence, traffic jams often, and happens mainly because the city can only be crossed by the center. Lithuania, as the rest of Europe experienced a big growth, from 1995 to 2005 coinciding with the crisis, that is to say that number of cars increased to highest levels as well as the ...

  16. Automated Traffic Enforcement in France

    OpenAIRE

    BRIQUET, Philippe; CANEL, A

    2002-01-01

    One of the goals of traffic safety in cities and between cities is to increase compliance with Traffic Regulations. For this purpose, the French Ministry of Transportation decided to set up an automated traffic enforcement program. This program currently focuses on several types of violations : speeding, spacing between vehicles, and traffic light and railway crossing. This article presents the main goals of the program and the expected challenges and characteristics of operations that have b...

  17. Reverse Stackelberg Games: Theory and Applications in Traffic Control

    NARCIS (Netherlands)

    Groot, N.B.

    2013-01-01

    One of the major challenges in optimization-based control of large-scale intelligent infrastructural networks such as traffic networks is to find efficient multilevel optimization schemes through which decisions can be made by agents or controllers of different interacting layers. The hierarchical

  18. Advanced treatment of municipal wastewater by nanofiltration: Operational optimization and membrane fouling analysis.

    Science.gov (United States)

    Li, Kun; Wang, Jianxing; Liu, Jibao; Wei, Yuansong; Chen, Meixue

    2016-05-01

    Municipal sewage from an oxidation ditch was treated for reuse by nanofiltration (NF) in this study. The NF performance was optimized, and its fouling characteristics after different operational durations (i.e., 48 and 169hr) were analyzed to investigate the applicability of nanofiltration for water reuse. The optimum performance was achieved when transmembrane pressure=12bar, pH=4 and flow rate=8L/min using a GE membrane. The permeate water quality could satisfy the requirements of water reclamation for different uses and local standards for water reuse in Beijing. Flux decline in the fouling experiments could be divided into a rapid flux decline and a quasi-steady state. The boundary flux theory was used to predict the evolution of permeate flux. The expected operational duration based on the 169-hr experiment was 392.6hr which is 175% longer than that of the 48-hr one. High molecular weight (MW) protein-like substances were suggested to be the dominant foulants after an extended period based on the MW distribution and the fluorescence characteristics. The analyses of infrared spectra and extracellular polymeric substances revealed that the roles of both humic- and polysaccharide-like substances were diminished, while that of protein-like substances were strengthened in the contribution of membrane fouling with time prolonged. Inorganic salts were found to have marginally influence on membrane fouling. Additionally, alkali washing was more efficient at removing organic foulants in the long term, and a combination of water flushing and alkali washing was appropriate for NF fouling control in municipal sewage treatment. PMID:27155415

  19. Reactive Planning of Autonomous Vehicles for Traffic Scenarios

    OpenAIRE

    Rahul Kala; Kevin Warwick

    2015-01-01

    Autonomous vehicles operate in real time traffic scenarios and aim to reach their destination from their source in the most efficient manner possible. Research in mobile robotics provides a variety of sophisticated means with which to plan the path of these vehicles. Conversely professional human drivers usually drive using instinctive means, which enables them to reach their goal almost optimally whilst still obeying all traffic laws. In this paper we propose the use of fuzzy logic for novel...

  20. Road Pricing, Traffic Congestion and Economic Welfare: A Note

    OpenAIRE

    Ingo_Böbel; Casimir de Rham

    2004-01-01

    Only recently, the subject of road pricing to reduce traffic congestion gained increasing importance in Europe. This paper uses a standard microeconomic approach to show that road user price charging to avoid traffic congestion is optimal from a society’s point of view as it improves economic efficiency of allocating a scarce resource (road space) by reducing the welfare loss (as being measured by a loss in consumer surplus) for everyone in the society.

  1. Effect of multi-velocity-difference in traffic flow

    Institute of Scientific and Technical Information of China (English)

    Mo Ye-Liu; He Hong-Di; Xue Yu; Shi Wei; Lu Wei-Zhen

    2008-01-01

    Based on the optimal velocity models, an extended model is proposed, in which multi-velocity-difference ahead is taken into consideration. The damping effect of the multi-velocity-difference ahead has been investigated by means of analytical and numerical methods. Results indicate that the multi-velocity-difference leads to the enhancement of stability of traffic flow, suppression of the emergence of traffic jamming, and reduction of the energy consumption.

  2. Design of an Agent Based Traffic-Information Collection System

    OpenAIRE

    Kenedy Aliila Greyson

    2012-01-01

    Currently, traffic congestions are common events in road networks of main cities in developing countries. It has been observed that, the size of congestion increases year after year. For traffic congestion management to work efficiently, sufficiently and accurately information are needed. In this research we present an alternative method using agent technology to collect and manipulate data so as to be used in optimizing the vehicle flow within the road networks. The objective is to design an...

  3. Criterion for traffic phases in single vehicle data and empirical test of a microscopic three-phase traffic theory

    International Nuclear Information System (INIS)

    Based on empirical and numerical microscopic analyses, the physical nature of a qualitatively different behaviour of the wide moving jam phase in comparison with the synchronized flow phase-microscopic traffic flow interruption within the wide moving jam phase-is found. A microscopic criterion for distinguishing the synchronized flow and wide moving jam phases in single vehicle data measured at a single freeway location is presented. Based on this criterion, empirical microscopic classification of different local congested traffic states is performed. Simulations made show that the microscopic criterion and macroscopic spatiotemporal objective criteria lead to the same identification of the synchronized flow and wide moving jam phases in congested traffic. Microscopic models in the context of three-phase traffic theory have been tested based on the microscopic criterion for the phases in congested traffic. It is found that microscopic three-phase traffic models can explain both microscopic and macroscopic empirical congested pattern features. It is obtained that microscopic frequency distributions for vehicle speed difference as well as fundamental diagrams and speed correlation functions can depend on the spatial co-ordinate considerably. It turns out that microscopic optimal velocity (OV) functions and time headway distributions are not necessarily qualitatively different, even if local congested traffic states are qualitatively different. The reason for this is that important spatiotemporal features of congested traffic patterns are lost in these as well as in many other macroscopic and microscopic traffic characteristics, which are widely used as the empirical basis for a test of traffic flow models, specifically, cellular automata traffic flow models

  4. Traffic sign detection and analysis

    DEFF Research Database (Denmark)

    Møgelmose, Andreas; Trivedi, Mohan M.; Moeslund, Thomas B.

    Traffic sign recognition (TSR) is a research field that has seen much activity in the recent decade. This paper introduces the problem and presents 4 recent papers on traffic sign detection and 4 recent papers on traffic sign classification. It attempts to extract recent trends in the field and...

  5. Optimizing Music Learning: Exploring How Blocked and Interleaved Practice Schedules Affect Advanced Performance

    Science.gov (United States)

    Carter, Christine E.; Grahn, Jessica A.

    2016-01-01

    Repetition is the most commonly used practice strategy by musicians. Although blocks of repetition continue to be suggested in the pedagogical literature, work in the field of cognitive psychology suggests that repeated events receive less processing, thereby reducing the potential for long-term learning. Motor skill learning and sport psychology research offer an alternative. Instead of using a blocked practice schedule, with practice completed on one task before moving on to the next task, an interleaved schedule can be used, in which practice is frequently alternated between tasks. This frequent alternation involves more effortful processing, resulting in increased long-term learning. The finding that practicing in an interleaved schedule leads to better retention than practicing in a blocked schedule has been labeled the “contextual interference effect.” While the effect has been observed across a wide variety of fields, few studies have researched this phenomenon in a music-learning context, despite the broad potential for application to music practice. This study compared the effects of blocked and interleaved practice schedules on advanced clarinet performance in an ecologically valid context. Ten clarinetists were given one concerto exposition and one technical excerpt to practice in a blocked schedule (12 min per piece) and a second concerto exposition and technical excerpt to practice in an interleaved schedule (3 min per piece, alternating until a total of 12 min of practice were completed on each piece). Participants sight-read the four pieces prior to practice and performed them at the end of practice and again one day later. The sight-reading and two performance run-throughs of each piece were recorded and given to three professional clarinetists to rate using a percentage scale. Overall, whenever there was a ratings difference between the conditions, pieces practiced in the interleaved schedule were rated better than those in the blocked schedule

  6. Optimizing Music Learning: Exploring How Blocked and Interleaved Practice Schedules Affect Advanced Performance.

    Science.gov (United States)

    Carter, Christine E; Grahn, Jessica A

    2016-01-01

    Repetition is the most commonly used practice strategy by musicians. Although blocks of repetition continue to be suggested in the pedagogical literature, work in the field of cognitive psychology suggests that repeated events receive less processing, thereby reducing the potential for long-term learning. Motor skill learning and sport psychology research offer an alternative. Instead of using a blocked practice schedule, with practice completed on one task before moving on to the next task, an interleaved schedule can be used, in which practice is frequently alternated between tasks. This frequent alternation involves more effortful processing, resulting in increased long-term learning. The finding that practicing in an interleaved schedule leads to better retention than practicing in a blocked schedule has been labeled the "contextual interference effect." While the effect has been observed across a wide variety of fields, few studies have researched this phenomenon in a music-learning context, despite the broad potential for application to music practice. This study compared the effects of blocked and interleaved practice schedules on advanced clarinet performance in an ecologically valid context. Ten clarinetists were given one concerto exposition and one technical excerpt to practice in a blocked schedule (12 min per piece) and a second concerto exposition and technical excerpt to practice in an interleaved schedule (3 min per piece, alternating until a total of 12 min of practice were completed on each piece). Participants sight-read the four pieces prior to practice and performed them at the end of practice and again one day later. The sight-reading and two performance run-throughs of each piece were recorded and given to three professional clarinetists to rate using a percentage scale. Overall, whenever there was a ratings difference between the conditions, pieces practiced in the interleaved schedule were rated better than those in the blocked schedule

  7. Advanced Start of Combustion Sensor Phases I and II-A: Feasibility Demonstration, Design and Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Chad Smutzer

    2010-01-31

    Homogeneous Compressed Charge Ignition (HCCI) has elevated the need for Start of Combustion (SOC) sensors. HCCI engines have been the exciting focus of engine research recently, primarily because HCCI offers higher thermal efficiency than the conventional Spark Ignition (SI) engines and significantly lower NOx and soot emissions than conventional Compression Ignition (CI) engines, and could be fuel neutral. HCCI has the potential to unify all the internal combustion engine technology to achieve the high-efficiency, low-emission goal. However, these advantages do not come easy. It is well known that the problems encountered with HCCI combustion center on the difficulty of controlling the Start of Combustion. TIAX has an SOC sensor under development which has shown promise. In previous work, including a DOE-sponsored SBIR project, TIAX has developed an accelerometer-based method which was able to determine SOC within a few degrees crank angle for a range of operating conditions. A signal processing protocol allows reconstruction of the combustion pressure event signal imbedded in the background engine vibration recorded by the accelerometer. From this reconstructed pressure trace, an algorithm locates the SOC. This SOC sensor approach is nonintrusive, rugged, and is particularly robust when the pressure event is strong relative to background engine vibration (at medium to high engine load). Phase I of this project refined the previously developed technology with an engine-generic and robust algorithm. The objective of the Phase I research was to answer two fundamental questions: Can the accelerometer-based SOC sensor provide adequate SOC event capture to control an HCCI engine in a feedback loop? And, will the sensor system meet cost, durability, and software efficiency (speed) targets? Based upon the results, the answer to both questions was 'YES'. The objective of Phase II-A was to complete the parameter optimization of the SOC sensor prototype in order

  8. Minimization of total overlay errors on product wafers using an advanced optimization scheme

    Science.gov (United States)

    Levinson, Harry J.; Preil, Moshe E.; Lord, Patrick J.

    1997-07-01

    The matching of wafer steppers is accomplished typically by patterning two successive layers, using different steppers of interest for each layer, and measuring the overlay at many points in the exposure field. Matching is considered to be optimized when some metric, such the sum-of-squares of overlay errors, is minimized over all measured points within the field. This is to be contrasted to the situation which arises during the in-line measurement of overlay errors in production, where a far more limited sampling of points is involved. There are several consequences to limited sampling. Adjustable intrafield overlay components, such as magnification, may appear to vary up to several parts-per- million as a consequence of varying chip size. These variations are substantially larger than the normal variations of these components for fixed field sizes, and so have significant consequences for the application of statistical methodologies to the control of overlay components. The width of the distribution of overlay errors across the field may typically increase between 10 to 20 nm (3(sigma) ), with even larger increases in mean shifts, all varying with field size. Reticles may also introduce similar variations, both random and systematic. Reticle beam-writer errors lead to systematic intrafield errors, particularly asymmetric field magnification and field skew. Steppers may compensate for these systematic reticle errors, and step- and-scan systems are more effective at this compensation than step-and-repeat machines. For steppers which have process dependent alignment, this compensation must be determined on products, which leads back to the problems associated with limited sampling. Correction for the overlay errors induced by limited sampling may be accomplished by look-up tables incorporated into the overlay analysis software. For each pair of steppers and each sampling plan, corrections can be applied at each measurement point in order to bring the full field and

  9. Study and optimization of lower hybrid wave coupling in the experimental advanced superconducting (EAST) tokamak

    International Nuclear Information System (INIS)

    The results presented in this paper are an extension of our recent (Kong et al 2012 Plasma Phys. Control. Fusion 54 105003) studies on lower hybrid wave (LHW) coupling. By optimizing the shape of the LH grill, the misalignment between the poloidal limiter (PL) and the LH grill is nearly eliminated and the coupling of LHW is improved, especially on the top row, although some discrepancies are still present in the case with low edge density. Density modifications both by LHW and ion cyclotron range of frequency (ICRF) power are studied in EAST. Experimental results show that the edge density modification in front of the LH grill during LHW power depends mainly on the competition between ponderomotive force (PMF) and the ionization of neutral gas, provided by gas puffing and edge recycling. However, the local edge density during ICRF power can be reduced rapidly. Furthermore, such a modification is more obvious with higher ICRF power and the relevant mechanism of density modification by ICRF power can be related to RF sheaths. In addition, another analogous effect of RF sheaths on the coupling of LHW is also investigated, i.e. the density convection induced by Er × B drift. The changes in LHW coupling associated with different ICRF antennas are discussed and it is shown that in some cases the coupling on the lower rows of the LH grill is improved possibly due to magnetic connection between ICRF antennas and the LH grill. The local coupling of LHW can be improved by gas puffing from gas introduction modules (GIM) on both sides of the launcher, but it is difficult to judge which one is more beneficial due to errors in measurements. Experimental results with gas (D2) injection during ICRF power clearly show that the coupling of LHW on the upper rows will be first improved by gas injection on the electron side and the coupling on the lower rows will be effectively improved by gas injection on the ion side. The results are consistent with the mapping of field lines

  10. Effects of Traffic Lights on CA Traffic Model

    Institute of Scientific and Technical Information of China (English)

    SuweiFENG; GuoqingGU

    1997-01-01

    Cellular automaton traffic models can include various factors in traffic system with simple regulations and the corresponding computations and simulations are rather convenient and effective.In this paper,the Biham-Middleton-Levine model(briefly saying the BML model)is improved by removing its limitation of synchronized change of traffic lights.In new model,the traffic light at each crossing could arbitrarily change its starting time and tempo of variation and hence the model could more realistically describe the influence of traffic lights on the performance of traffic systems.The cases of traffic light with unsynchronized starting time and different tempo of variation are simulated in this paper.

  11. Traffic flow on realistic road networks with adaptive traffic lights

    CERN Document Server

    de Gier, Jan; Rojas, Omar

    2010-01-01

    We present a model of traffic flow on generic urban road networks based on cellular automata. We apply this model to an existing road network in the Australian city of Melbourne, using empirical data as input. For comparison, we also apply this model to a square-grid network using hypothetical input data. On both networks we compare the effects of non-adative vs adaptive traffic lights, in which instantaneous traffic state information feeds back into the traffic signal schedule. We observe that not only do adaptive traffic lights result in better averages of network observables, they also lead to significantly smaller fluctuations in these observables. We furthermore compare two different systems of adaptive traffic signals, one which is informed by the traffic state on both upstream and downstream links, and one which is informed by upstream links only. We find that, in general, the total travel time is smallest when using the joint upstream-downstream control strategy.

  12. Advancing adaptive optics technology: Laboratory turbulence simulation and optimization of laser guide stars

    Science.gov (United States)

    Rampy, Rachel A.

    optimizing the laser beacons used to bring AO correction to parts of the sky that lack a naturally bright light source for measuring atmospheric distortion. Long pulse length laser guide stars (LGS) that use fluorescence from the D 2 transition in mesospheric sodium are valuable both due to their high altitude, and because they permit Rayleigh blanking and fratricide avoidance in multiple LGS systems. Bloch equation simulations of sodium-light interactions in Mathematica show that certain spectral formats and pulse lengths (on the order of 30 μs), with high duty cycles (20-50%), should be able to achieve photon returns within 10% of what is seen from continuous wave (CW) excitation. Utilizing this recently developed code (called LGSBloch), I investigated the time dependent characteristics of sodium fluorescence. I then identified the optimal format for the new LGS that will be part of the upgrade to the AO system on the Shane 3 meter telescope at the Lick Observatory. I discuss these results, along with their general applicability to other LGS systems, and provide a brief description of the potential benefits of uplink correction. Predictions from the LGSBloch simulation package are compared to data from currently operating LGS systems. For a CW LGS, the return flux measurements and theory show reasonable agreement, but for short pulse lasers, such as those at the Lick and Keck Observatories, the code seems to be overestimating the data by a factor of 2--3. Several tactics to explicate this discrepancy are explored, such as verifying parameters involved in the measurements and including greater detail in the modeling. Although these efforts were unsuccessful at removing the discrepancy, they illuminated other facets of the problem that deserve further consideration. Use of the sophisticated LGSBloch model has allowed detailed study of the evolution of the energy level populations and other physical effects (e.g. Larmor precession, atomic recoil, and collisions). This has

  13. Research on Prediction of Traffic Congestion State

    Directory of Open Access Journals (Sweden)

    Zhao Jun

    2015-01-01

    Full Text Available This method of prediction using the data mining to analyze huge amounts of data as a preferred tool has been widely used in various fields. In the midst of it, the routine traffic data exists in a large number of isolated data in real time without establishing relationships with other data, and detects the amount of data which is greater than that at present. The usage of these data which is relatively shallow requires an in-depth analysis of its data model. Therefore, this paper uses a fuzzy clustering analysis method of feature points to study the traffic flow, uses a Markov decision chain model to study traffic jams, uses quantitative sample points based on the information entropy to calculate traffic flow trends and uses a heuristic prediction model to predict the road con-gestion. Through the simulation experiment which verifies the correctness of the model, this research is to advance the development of the road and to provide a basis for a dredging plan.

  14. Wavelet filtering of network traffic measurements

    Science.gov (United States)

    Antoniou, I.; Ivanov V., Vi.; Ivanov, Va. V.; Zrelov, P. V.

    2003-06-01

    The “Caterpillar”-SSA (Principal Components of Time Series: Caterpillar Method, St. Petersburg University Press, 1997; Analysis of Time Series Structure: SSA and Related Techiques, Chapman & Hall/CRC, London/Boca Raton, FL, 2001) and statistical analysis based on the joint utilization of χ2 and ω2 tests provided the possibility to divide the whole set of components into two classes (VIII International Workshop on Advanced Computing and Analysis Techniques in Physics Research, ACAT’2002, 24-28 June 2002, Moscow, Russia, Book of abstracts, p. 176 (submitted to Physica D)). The first class includes leading components responsible for the main contribution to network traffic (Physica D 167 (2002) 72), and the second class involves residual components that can be interpreted as noise. More detailed analysis of the boundary region between these two classes may give additional information on traffic components and, thus, simplify the understanding of traffic dynamics. In this connection, we apply wavelet filtering to traffic measurements, and analyze its influence both on the characteristics of individual principal components and on the sum distributions of leading and residual components.

  15. CATS-based Air Traffic Controller Agents

    Science.gov (United States)

    Callantine, Todd J.

    2002-01-01

    This report describes intelligent agents that function as air traffic controllers. Each agent controls traffic in a single sector in real time; agents controlling traffic in adjoining sectors can coordinate to manage an arrival flow across a given meter fix. The purpose of this research is threefold. First, it seeks to study the design of agents for controlling complex systems. In particular, it investigates agent planning and reactive control functionality in a dynamic environment in which a variety perceptual and decision making skills play a central role. It examines how heuristic rules can be applied to model planning and decision making skills, rather than attempting to apply optimization methods. Thus, the research attempts to develop intelligent agents that provide an approximation of human air traffic controller behavior that, while not based on an explicit cognitive model, does produce task performance consistent with the way human air traffic controllers operate. Second, this research sought to extend previous research on using the Crew Activity Tracking System (CATS) as the basis for intelligent agents. The agents use a high-level model of air traffic controller activities to structure the control task. To execute an activity in the CATS model, according to the current task context, the agents reference a 'skill library' and 'control rules' that in turn execute the pattern recognition, planning, and decision-making required to perform the activity. Applying the skills enables the agents to modify their representation of the current control situation (i.e., the 'flick' or 'picture'). The updated representation supports the next activity in a cycle of action that, taken as a whole, simulates air traffic controller behavior. A third, practical motivation for this research is to use intelligent agents to support evaluation of new air traffic control (ATC) methods to support new Air Traffic Management (ATM) concepts. Current approaches that use large, human

  16. Urban Road Traffic Simulation Techniques

    Directory of Open Access Journals (Sweden)

    Ana Maria Nicoleta Mocofan

    2011-09-01

    Full Text Available For achieving a reliable traffic control system it is necessary to first establish a network parameter evaluation system and also a simulation system for the traffic lights plan. In 40 years of history, the computer aided traffic simulation has developed from a small research group to a large scale technology for traffic systems planning and development. In the following thesis, a presentation of the main modeling and simulation road traffic applications will be provided, along with their utility, as well as the practical application of one of the models in a case study.

  17. Traffic Management as a Service: The Traffic Flow Pattern Classification Problem

    Directory of Open Access Journals (Sweden)

    Carlos T. Calafate

    2015-01-01

    Full Text Available Intelligent Transportation System (ITS technologies can be implemented to reduce both fuel consumption and the associated emission of greenhouse gases. However, such systems require intelligent and effective route planning solutions to reduce travel time and promote stable traveling speeds. To achieve such goal these systems should account for both estimated and real-time traffic congestion states, but obtaining reliable traffic congestion estimations for all the streets/avenues in a city for the different times of the day, for every day in a year, is a complex task. Modeling such a tremendous amount of data can be time-consuming and, additionally, centralized computation of optimal routes based on such time-dependencies has very high data processing requirements. In this paper we approach this problem through a heuristic to considerably reduce the modeling effort while maintaining the benefits of time-dependent traffic congestion modeling. In particular, we propose grouping streets by taking into account real traces describing the daily traffic pattern. The effectiveness of this heuristic is assessed for the city of Valencia, Spain, and the results obtained show that it is possible to reduce the required number of daily traffic flow patterns by a factor of 4210 while maintaining the essence of time-dependent modeling requirements.

  18. Exploiting Witness for Traffic Simulation

    Directory of Open Access Journals (Sweden)

    Azhar Ismail

    2014-03-01

    Full Text Available Traffic congestion in urban cities is an increasing problem. Not only does it lead to an increase in pollution, but the time spent waiting in traffic queues wastes valuable time in addition to causing frustration. A system that can control and manage traffic efficiently is one way that this issue can be reduced. A specific road traffic intersection in South Manchester, UK, was selected for investigation as it experiences high levels of traffic flow through it during the evening peak time. This has led to large queues and long waiting times due to the fixed timings of the traffic lights. This paper explores strategies to better control the traffic flow through it. A model of the selected traffic junction has been built using Witness simulation software. Data for this junction has been obtained partially from observations and mostly from traffic surveys enabling a simulation of the traffic flow. Analysing the results allowed two alternative scenarios to be developed and simulated. Results from one of the scenarios showed noticeable reductions in the average queue waiting times at the traffic junction.

  19. Web traffic and firm performance

    DEFF Research Database (Denmark)

    Farooq, Omar; Aguenaou, Samir

    2013-01-01

    Does the traffic generated by websites of firms signal anything to stock market participants? Does higher web-traffic translate into availability of more information and therefore lower agency problems? And if answers to above questions are in affirmative, does higher web-traffic traffic translate...... into better firm performance? This paper aims to answer these questions by documenting a positive relationship between the extent of web-traffic and firm performance in the MENA region during the 2010. We argue that higher web-traffic lowers the agency problems in firms by disseminating more information...... to stock market participants. Consequently, lower agency problems translate into better performance. Furthermore, we also show that agency reducing role of web-traffic is more pronounced in regimes where information environment is already bad. For example, our results show stronger impact of web...

  20. Traffic Light Detection

    DEFF Research Database (Denmark)

    Philipsen, Mark Philip; Jensen, Morten Bornø; Møgelmose, Andreas; Moeslund, Thomas B.; Trivedi, Mohan M.

    Traffic light recognition (TLR) is an integral part of any intelligent vehicle, which must function in the existing infrastructure. Pedestrian and sign detection have recently seen great improvements due to the introduction of learning based detectors using integral channel features. A similar push...... database is collected based on footage from US roads. The database consists of both test and training data, totaling 46,418 frames and 112,971 annotated traffic lights, captured in continuous sequences under a varying light and weather conditions. The learning based detector achieves an AUC of 0.4 and 0...... have not yet been seen for the detection sub-problem of TLR, where detection is dominated by methods based on heuristic models. Evaluation of existing systems is currently limited primarily to small local datasets. In order to provide a common basis for comparing future TLR research an extensive public...

  1. Inaccuracy in traffic forecasts

    DEFF Research Database (Denmark)

    Flyvbjerg, Bent; Holm, Mette K. Skamris; Buhl, Søren Ladegaard

    2006-01-01

    This paper presents results from the first statistically significant study of traffic forecasts in transportation infrastructure projects. The sample used is the largest of its kind, covering 210 projects in 14 nations worth US$58 billion. The study shows with very high statistical significance...... that forecasters generally do a poor job of estimating the demand for transportation infrastructure projects. The result is substantial downside financial and economic risk. Forecasts have not become more accurate over the 30-year period studied. If techniques and skills for arriving at accurate demand...... reference class forecasting. Highly inaccurate traffic forecasts combined with large standard deviations translate into large financial and economic risks. But such risks are typically ignored or downplayed by planners and decision-makers, to the detriment of social and economic welfare. The paper presents...

  2. Physics of Traffic Flow

    Science.gov (United States)

    Davis, L. C.

    2015-03-01

    The Texas A&M Transportation Institute estimated that traffic congestion cost the United States 121 billion in 2011 (the latest data available). The cost is due to wasted time and fuel. In addition to accidents and road construction, factors contributing to congestion include large demand, instability of high-density free flow and selfish behavior of drivers, which produces self-organized traffic bottlenecks. Extensive data collected on instrumented highways in various countries have led to a better understanding of traffic dynamics. From these measurements, Boris Kerner and colleagues developed a new theory called three-phase theory. They identified three major phases of flow observed in the data: free flow, synchronous flow and wide moving jams. The intermediate phase is called synchronous because vehicles in different lanes tend to have similar velocities. This congested phase, characterized by lower velocities yet modestly high throughput, frequently occurs near on-ramps and lane reductions. At present there are only two widely used methods of congestion mitigation: ramp metering and the display of current travel-time information to drivers. To find more effective methods to reduce congestion, researchers perform large-scale simulations using models based on the new theories. An algorithm has been proposed to realize Wardrop equilibria with real-time route information. Such equilibria have equal travel time on alternative routes between a given origin and destination. An active area of current research is the dynamics of connected vehicles, which communicate wirelessly with other vehicles and the surrounding infrastructure. These systems show great promise for improving traffic flow and safety.

  3. Organic traffic control

    OpenAIRE

    Prothmann, Holger

    2011-01-01

    Modern cities cannot be imagined without traffic lights controlling the road network. To handle the network's changing demands efficiently, the signal plan specification needs to be shifted from the design time to the run-time of a signal system. The generic observer/controller architecture proposed for Organic Computing facilitates this shift. A two-levelled learning mechanism optimises signal plans on-line while a distributed coordination mechanism establishes green waves in the road network.

  4. Untieing the Traffic Knot

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Beijing is working to resolve its longtime transportation problems before the 2008 Olympics One traffic jam after another, annoying horns, endless lines of cars,impatient sighs from passengers on an overcrowded bus, the youstomped-on-my-toe quarreling in the subway train, all have led to the unsurprising result that Beijing scored at the tail end of a survey of 287 cities in the category of transport satisfaction in China’s 2006 Report on the Quality of Urban Life.

  5. Assessing road traffic expression

    OpenAIRE

    Fábio Silva; Cesar Analide; Paulo Novais

    2014-01-01

    Road traffic is a problem which is increasing in cities with large population. Unrelated to this fact the number of portable and wearable devices has also been increasing throughout the population of most countries. With this advent, the capacity to monitor and register data about people habits and locations as well as more complex data such as intensity and strength of movements has created an opportunity to contribute to the general wealth and comfort within these environments. Ambient Inte...

  6. Topological-based bottleneck analysis and improvement strategies for traffic networks

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    A method is proposed to find key components of traffic networks with homogenous and heterogeneous topologies, in which heavier traffic flow is transported. One component, called the skeleton, is the minimum spanning tree (MST) based on the zero flow cost (ZCMST). The other component is the infinite incipient percolation cluster (IIC) which represents the spine of the traffic network. Then, a new method to analysis the property of the bottleneck in a large scale traffic network is given from a macroscopic and statistical viewpoint. Moreover, three effective strategies are proposed to alleviate traffic congestion. The significance of the findings is that one can significantly improve the global transport by enhancing the capacity in the ZCMST with a few links, while for improving the local traffic property, improving a tiny fraction of the traffic network in the IIC is effective. The result can be used to help traffic managers prevent and alleviate traffic congestion in time, guard against the formation of congestion bottleneck, and make appropriate policies for traffic demand management. Meanwhile, the method has very important theoretical significance and practical worthiness in optimizing traffic organization, traffic control, and disposal of emergency.

  7. The Physics of Traffic

    Science.gov (United States)

    Davis, L. Craig

    2006-03-01

    Congestion in freeway traffic is an example of self-organization in the language of complexity theory. Nonequilibrium, first-order phase transitions from free flow cause complex spatiotemporal patterns. Two distinct phases of congestion are observed in empirical traffic data--wide moving jams and synchronous flow. Wide moving jams are characterized by stopped or slowly moving vehicles within the jammed region, which widens and moves upstream at 15-20 km/h. Above a critical density of vehicles, a sudden decrease in the velocity of a lead vehicle can initiate a transition from metastable states to this phase. Human behaviors, especially delayed reactions, are implicated in the formation of jams. The synchronous flow phase results from a bottleneck such as an on-ramp. Thus, in contrast to a jam, the downstream front is pinned at a fixed location. The name of the phase comes from the equilibration (or synchronization) of speed and flow rate across all lanes caused by frequent vehicle lane changes. Synchronous flow occurs when the mainline flow and the rate of merging from an on-ramp are sufficiently large. Large-scale simulations using car-following models reproduce the physical phenomena occurring in traffic and suggest methods to improve flow and mediate congestion.

  8. Effects of traffic noise

    Energy Technology Data Exchange (ETDEWEB)

    Gottlob, D.

    1986-02-01

    One of the main sources of noise is road traffic. In 1984 there were over 25 million cars, 1.2 million lorries, 1.3 million motor cycles and 1.6 million mopeds using our roads. Opinion polls showed that 21% of the population felt that they were affected by traffic noise as a nuisance factor. An outline of the effects of this noise on the affected population is given, illustrated by diagrams. Details about noise emissions (drive-past level) of the different types of vehicles in city traffic are stated and the effects of noise described. The author goes into the nuisance effect (noise is not a physical factor, but a psychosocial one), changes in behaviour (ways of speaking, reduction of stress on households in proportion to rising income and higher educational levels) and the consequences for health (the reaction of the body to noise is primarily a consequence of the psychosomatic organisation of ow bodies). In conclusion, the author deals with the subjective efficiency of noise protection measures. (HWJ).

  9. Assessing Road Traffic Expression

    Directory of Open Access Journals (Sweden)

    Fábio Silva

    2014-12-01

    Full Text Available Road traffic is a problem which is increasing in cities with large population. Unrelated to this fact the number of portable and wearable devices has also been increasing throughout the population of most countries. With this advent, the capacity to monitor and register data about people habits and locations as well as more complex data such as intensity and strength of movements has created an opportunity to contribute to the general wealth and comfort within these environments. Ambient Intelligence and Intelligent Decision Making processes can benefit from the knowledge gathered by these devices to improve decisions on everyday tasks such as deciding navigation routes by car, bicycle or other means of transportation and avoiding route perils. The concept of computational sustainability may also be applied to this problem. Current applications in this area demonstrate the usefulness of real time system that inform the user of certain conditions in the surrounding area. On the other hand, the approach presented in this work aims to describe models and approaches to automatically identify current states of traffic inside cities and use methods from computer science to improve overall comfort and the sustainability of road traffic both with the user and the environment in mind. Such objective is delivered by analyzing real time contributions from those mobile ubiquitous devices to identifying problematic situations and areas under a defined criteria that have significant influence towards a sustainable use of the road transport infrastructure.

  10. Trace Analysis of Driver Behavior on Traffic Violator by Using Big Data (Traffic Program) in Korea

    OpenAIRE

    Lee, Jonghak

    2016-01-01

    This study aims to prove the effectiveness of traffic safety education program for traffic violators. Traffic violators who finished the traffic safety education programs were tracked down. In order to analyze the effectiveness of traffic safety education program, traffic violator’s data during ten-year period were used. This study analyzed how traffic violators changed their attitudes about traffic law abidance. Also predicted social benefits from traffic safety education program...

  11. Advances in LWD pressure measurements: smart, time optimized pretests and on demand real-time transmission applications

    Energy Technology Data Exchange (ETDEWEB)

    Serafim, Robson; Ferraris, Paolo [Schlumberger, Rio de Janeiro, RJ (Brazil)

    2008-07-01

    The StethoScope Logging While Drilling (LWD) Pressure Measurement, introduced in Brazil in 2005, has been extensively used in deep water environment to provide reservoir pressure and mobility in real-time. In the last three years the StethoScope service was further enhanced to allow better real time monitoring using a larger transmission rate, higher RT data resolution and remote visualization. In order to guarantee stable formation pressures with a limited test duration under a wide range of conditions, Time Optimized Pretests (TOP) were developed. These tests adjust automatically drawdown and buildup parameters as a function of formation characteristics (pressure/mobility) without requiring any input from the operator. On-demand frame (ODF), an advanced telemetry triggered automatically during the pressure tests, allowed to increase equivalent transmission rate and resolution and to include quality indices computed downhole. This paper is focused on the TOP and ODF Field Test results in Brazil, which proved to be useful and reliable options for better real-time decisions together with remote monitoring visualization implemented by the RTMonitor program. (author)

  12. 采用系统科学方法优化交通信号灯的控制策略%Optimization Control Strategy of Traffic Signal with System Scientific Methods

    Institute of Scientific and Technical Information of China (English)

    张世良

    2012-01-01

    In order to control vehicles easily pass in the intersection,on the basis of the introduction of system structure for traffic signal lamp,run mode and workflow,this paper analyzes different ways in system control which can use different operation patterns at different times to adaptively control vehicle pass time.Traffic induction strategies which can use different open moment according to the space between the two intersections is used to reduce waiting time for vehicle,improve pass efficiency and ensure efficient circulation in the whole traffic system,and other traffic information,such as vehicle speed,type and traffic by vehicle labels can provide basic data of traffic forecast for the road long-term planning and is signality to direct intelligent traffic control.%为了控制车辆在交叉路口顺畅通行,本文在介绍交通信号灯系统结构、运行模式及工作流程的基础上,分析了系统控制中不同策略的方法,使用在不同的时段采用不同的路口控制模式,自适应地控制车辆通行时间,并根据路口间距采用不同的开启时刻以及使用交通诱导策略,减少车辆等待时间,提高车辆通行效率,保证整个交通系统的高效流通,而且通过车载标签及时掌握的车速、车型和交通量等交通信息可以为该路段远期规划的交通预测提供基础数据,对智能交通控制具有很大的指导意义。

  13. Macroscopic Model and Simulation Analysis of Air Traffic Flow in Airport Terminal Area

    Directory of Open Access Journals (Sweden)

    Honghai Zhang

    2014-01-01

    Full Text Available We focus on the spatiotemporal characteristics and their evolvement law of the air traffic flow in airport terminal area to provide scientific basis for optimizing flight control processes and alleviating severe air traffic conditions. Methods in this work combine mathematical derivation and simulation analysis. Based on cell transmission model the macroscopic models of arrival and departure air traffic flow in terminal area are established. Meanwhile, the interrelationship and influential factors of the three characteristic parameters as traffic flux, density, and velocity are presented. Then according to such models, the macro emergence of traffic flow evolution is emulated with the NetLogo simulation platform, and the correlativity of basic traffic flow parameters is deduced and verified by means of sensitivity analysis. The results suggest that there are remarkable relations among the three characteristic parameters of the air traffic flow in terminal area. Moreover, such relationships evolve distinctly with the flight procedures, control separations, and ATC strategies.

  14. Traffic Control by Traffic Wardens in Minna, Niger State, Nigeria

    Directory of Open Access Journals (Sweden)

    P. N. NDOKE

    2006-01-01

    Full Text Available Traffic control by traffic wardens on three at-grade interactions in Minna, Northern Nigeria has been analysed. During the morning peak periods, it was observed that with traffic warden control, none of the approaches of the intersections operated beyond level of service E. However, when the wardens did not control traffic, the approaches operated at level of service, F, which has been shown in studies to be unacceptable to most drivers. Taking other factors like stability of electricity supply, motorists’ behaviour and society’s acceptance of innovations into consideration, it has been concluded that for now, there is no alternative to the traffic warden in traffic control in developing cities.

  15. Traffic Data and Their Implications for Consistent Traffic Flow Modeling

    OpenAIRE

    Helbing, Dirk

    1998-01-01

    The paper analyzes traffic data of the Dutch freeway A9 with respect to certain aspects which are relevant for traffic flow modeling as well as the calibration of model parameters and functions. Apart from the dynamic velocity distribution, the density-dependence and the temporal evolution of various, partly lane-specific quantities is investigated. The results are well compatible with recent macroscopic traffic flow models which have been derived from the dynamics of driver-vehicle units. Th...

  16. Evaluation of Traffic Management Measures on Road Traffic Noise

    OpenAIRE

    Bhaskar, A.; Chung, E; Dumont, A.-G.

    2006-01-01

    Road traffic noise affects the quality of life in the areas adjoining the road. The effect of traffic noise on people is wide ranging and may include sleep disturbance and negative impact on work efficiency. To address the problem of traffic noise, it is necessary to estimate the noise level. For this, a number of noise estimation models have been developed which can estimate noise at the receptor points, based on simple configuration of buildings. Howe...

  17. From Traffic Flow to Economic System

    Science.gov (United States)

    Bando, M.

    The optimal velocity model which is applied to traffic flow phenomena explains a spontaneous formation of traffic congestion. We discuss why the model works well in describing both free-flow and congested flow states in a unified way. The essential ingredient is that our model takes account of a sort of time delay in reacting to a given stimulus. This causes instability of many-body system, and yields a kind of phase transition above a certain critical density. Especially there appears a limit cycle on the phase space along which individual vehicle moves, and they show cyclic behavior. Once that we recognize the mechanism the same idea can be applied to a variety of phenomena which show cyclic behavior observed in many-body systems. As an example of such applications, we investigate business cycles commonly observed in economic system. We further discuss a possible origin of a kind of cyclic behavior observed in climate change.

  18. Imitation dynamics in a game of traffic

    CERN Document Server

    Paissan, Gabriel H

    2013-01-01

    We study a model of traffic where drivers adopt different behavioral strategies. These can be cooperative or defective according to a driver abiding or not by a traffic rule. Drivers can change their strategy by imitating the majority, with a rule that depends on the strategies with which they have interacted. These interactions occur at intersections, where vehicles pay a temporal cost according to their strategy. We analyze the conditions under which different strategy compositions represent an advantage in the system velocity. We found that the cooperators' mean speed is higher than the defectors' even when the vehicle density is large. However, defectors can obtain benefits in their mean speed when they are a minority in an essentially cooperative population. The presence of a core of educated drivers, who persist firmly in a cooperative behavior, optimizes the speed in the system, especially for intermediate values of vehicular density and higher temporal costs.

  19. Traffic flow in a Manhattan-like urban system

    CERN Document Server

    Li, Ming; Jiang, Rui; Hu, Mao-Bin; Wang, Bing-Hong

    2011-01-01

    In this paper, a cellular automaton model of vehicular traffic in Manhattan-like urban system is proposed. In this model, the origin-destination trips and traffic lights have been considered. The system exhibits three different states, i.e., moving state, saturation state and global deadlock state. With a grid coarsening method, vehicle distribution in the moving state and the saturation state has been studied. Interesting structures (e.g., windmill-like one, T-shirt-like one, Y-like one) have been revealed. A metastability of the system is observed in the transition from saturation state to global deadlock state. The effect of advanced traveller information system (ATIS), the traffic light period, and the traffic light switch strategy have also been investigated.

  20. Alternate Routing in Tandem Traffic-Groomed Optical Networks

    Directory of Open Access Journals (Sweden)

    Alicia Nicki Washington

    2007-09-01

    Full Text Available Recent advances in telecommunication networks have allowed WDM to emerge as a viable solution to the ever-increasing demands of the Internet. Because these networks carry large amounts of traffic, alternate routing methods are designed in order to allow traffic to be properly re-routed from source to destination in the event of certain events, such as link blocking or failure. In this paper, we consider a tandem traffic-groomed optical network, modeled as a multi-level overflow system, where each level represents a wavelength between adjacent nodes. The queueing network is analyzed using a combination of methods. As will be shown, the decomposition method provides a good approximate analysis of large overflow systems supporting traffic from multiple sources.

  1. Traffic flow in a Manhattan-like urban system

    Science.gov (United States)

    Li, Ming; Ding, Zhong-Jun; Jiang, Rui; Hu, Mao-Bin; Wang, Bing-Hong

    2011-12-01

    In this paper, a cellular automaton model of vehicular traffic in a Manhattan-like urban system is proposed. In this model, the origin-destination trips and traffic lights have been considered. The system exhibits three different states, i.e. moving state, saturation state and global deadlock state. With a grid coarsening method, vehicle distribution in the moving state and the saturation state has been studied. Interesting structures (e.g. windmill-like ones, T-shirt-like ones, Y-like ones) have been revealed. A metastability of the system is observed in the transition from the saturation state to the global deadlock state. The effect of an advanced traveller information system (ATIS), the traffic light period and the traffic light switch strategy have also been investigated.

  2. Traffic flow in a Manhattan-like urban system

    International Nuclear Information System (INIS)

    In this paper, a cellular automaton model of vehicular traffic in a Manhattan-like urban system is proposed. In this model, the origin–destination trips and traffic lights have been considered. The system exhibits three different states, i.e. moving state, saturation state and global deadlock state. With a grid coarsening method, vehicle distribution in the moving state and the saturation state has been studied. Interesting structures (e.g. windmill-like ones, T-shirt-like ones, Y-like ones) have been revealed. A metastability of the system is observed in the transition from the saturation state to the global deadlock state. The effect of an advanced traveller information system (ATIS), the traffic light period and the traffic light switch strategy have also been investigated

  3. Camouflaging Timing Channels in Web Traffic

    OpenAIRE

    Sellke, Sarah H; Wang, Chih-Chun; Bagchi, Saurabh; Shroff, Ness B.

    2009-01-01

    Web traffic accounts for more than half of Internet traffic today. Camouflaging covert timing channels in Web traffic would be advantageous for concealment. In this paper, we investigate the possibility of disguising network covert timing channels as HTTP traffic to avoid detection. Extensive research has shown that Internet traffic, including HTTP traffic, exhibits self-similarity and long range persistence. Existing covert timing channels that mimic i.i.d. legitimate traffic cannot imitate ...

  4. Lagrangian Multi-Class Traffic State Estimation

    OpenAIRE

    Y. Yuan

    2013-01-01

    Road traffic is important to everybody in the world. People travel and commute everyday. For those who travel by cars (or other types of road vehicles), traffic congestion is a daily experience. One essential goal of traffic researchers is to reduce traffic congestion and to improve the whole traffic system operation and the environment. To achieve this goal, we have to first understand prevailing traffic situations, then perform pro-active traffic control and management. The estimation of tr...

  5. Help the Genetic Algorithm to Minimize the Urban Traffic on Intersections

    Directory of Open Access Journals (Sweden)

    Dadmehr Rahbari

    2014-09-01

    Full Text Available Control of traffic lights at the intersections of the main issues is the optimal traffic. Intersections to regulate traffic flow of vehicles and eliminate conflicting traffic flows are used. Modeling and simulation of traffic are widely used in industry. In fact, the modeling and simulation of an industrial system is studied before creating economically and when it is affordable. The aim of this article is a smart way to control traffic. The first stage of the project with the objective of collecting statistical data (cycle time of each of the intersection of the lights of vehicles is waiting for a red light steps where the data collection found optimal amounts next it is. Introduced by genetic algorithm optimization of parameters is performed. GA begin with coding step as a binary variable (the range specified by the initial data set is obtained will start with an initial population and then a new generation of genetic operators mutation and crossover and will Finally, the members of the optimal fitness values are selected as the solution set. The optimal output of Petri nets CPN TOOLS modeling and software have been implemented. The results indicate that the performance improvement project in intersections traffic control systems. It is known that other data collected and enforced intersections of evolutionary methods such as genetic algorithms to reduce the waiting time for traffic lights behind the red lights and to determine the appropriate cycle.

  6. Decentralized Traffic Management Strategies for Sensor-Enabled Cars

    CERN Document Server

    Wang, Ziyuan; Ramamohanarao, Kotagiri

    2009-01-01

    Traffic Congestions and accidents are major concerns in today's transportation systems. This thesis investigates how to optimize traffic flow on highways, in particular for merging situations such as intersections where a ramp leads onto the highway. In our work, cars are equipped with sensors that can detect distance to neighboring cars, and communicate their velocity and acceleration readings with one another. Sensor-enabled cars can locally exchange sensed information about the traffic and adapt their behavior much earlier than regular cars. We propose proactive algorithms for merging different streams of sensor-enabled cars into a single stream. A proactive merging algorithm decouples the decision point from the actual merging point. Sensor-enabled cars allow us to decide where and when a car merges before it arrives at the actual merging point. This leads to a significant improvement in traffic flow as velocities can be adjusted appropriately. We compare proactive merging algorithms against the conventio...

  7. Design of an Agent Based Traffic-Information Collection System

    Directory of Open Access Journals (Sweden)

    Kenedy Aliila Greyson

    2012-11-01

    Full Text Available Currently, traffic congestions are common events in road networks of main cities in developing countries. It has been observed that, the size of congestion increases year after year. For traffic congestion management to work efficiently, sufficiently and accurately information are needed. In this research we present an alternative method using agent technology to collect and manipulate data so as to be used in optimizing the vehicle flow within the road networks. The objective is to design an agent based system to provide sufficient and accurate information used in traffic flow management, and vehicle traffic congestion mitigation. The implementation approach is presented. The case study is a portion of the road network from the city of Dar es Salaam.

  8. Programming Methods for Road Traffic Control Video Applications

    Directory of Open Access Journals (Sweden)

    Răzvan Ghită

    2011-09-01

    Full Text Available This paper aims to present an application capable of detecting the road traffic load in urban areas using an infrastructure of video cameras in conjunction with a well known programming language: Lab View. The presentation will highlight the role played by video detection technology, what advantages it offers and some examples of its successful use in the area of public transports. Developments in recent years clearly show that video systems certainly can, and will, establish themselves in the market. Also, an important aspect of the application consist of the advantage that it can determine the degree of occupation of a traffic link at certain hours, but it also can realize a traffic optimization by interconnecting this application with a traffic light adaptive, control system.

  9. Macroscopic Model and Simulation Analysis of Air Traffic Flow in Airport Terminal Area

    OpenAIRE

    Honghai Zhang; Yan Xu; Lei Yang; Hao Liu

    2014-01-01

    We focus on the spatiotemporal characteristics and their evolvement law of the air traffic flow in airport terminal area to provide scientific basis for optimizing flight control processes and alleviating severe air traffic conditions. Methods in this work combine mathematical derivation and simulation analysis. Based on cell transmission model the macroscopic models of arrival and departure air traffic flow in terminal area are established. Meanwhile, the interrelationship and influential fa...

  10. Analysis of CO2 emission in traffic flow and numerical tests

    Science.gov (United States)

    Zhu, Wen-Xing

    2013-10-01

    We investigated the carbon dioxide emission rate in traffic flow analytically and numerically. The emission model was derived based on Bando’s optimal velocity model with a consideration of slope. Simulations were conducted to examine the relationship between the CO2 emission rate of vehicles and slope of road, traffic density, and road length. Analysis of the results shows that some original laws of CO2 emission in traffic flow with congestion were exhibited.

  11. Optimization and Optimal Control

    CERN Document Server

    Chinchuluun, Altannar; Enkhbat, Rentsen; Tseveendorj, Ider

    2010-01-01

    During the last four decades there has been a remarkable development in optimization and optimal control. Due to its wide variety of applications, many scientists and researchers have paid attention to fields of optimization and optimal control. A huge number of new theoretical, algorithmic, and computational results have been observed in the last few years. This book gives the latest advances, and due to the rapid development of these fields, there are no other recent publications on the same topics. Key features: Provides a collection of selected contributions giving a state-of-the-art accou

  12. Interdomain traffic engineering with BGP

    OpenAIRE

    Quoitin, Bruno; Uhlig, Steve; Pelsser, Cristel; Swinnen, Louis; Bonaventure, Olivier

    2003-01-01

    Traffic engineering is performed by means of a set of techniques that can be used to better control the flow of packets inside an IP network We discuss the utilization of these techniques across interdomain boundaries in the global Internet. We first analyze the characteristics of interdomain traffic on the basis of measurements from three different Internet service providers and show that a small number of sources are responsible for a large fraction of the traffic. Across interdomain bounda...

  13. Traffic noise and cardiovascular disease

    OpenAIRE

    Selander, Jenny

    2010-01-01

    Traffic noise is an increasing problem in urban areas worldwide, but health effects in relation to traffic noise exposure are not well understood. Several studies show that noise may give rise to acute stress reactions, possibly leading to cardiovascular effects, but the evidence is limited on cardiovascular risks associated with traffic noise exposure. Cardiovascular effects have been indicated for other environmental stressors such as occupational noise exposure and job ...

  14. HMM FEATURE MODELLING AND IMMUNE CLONE OPTIMAL CLASSIFICATION FOR ABNORMAL TRAFFIC EVENTS%交通异常事件HMM特征建模及免疫克隆优化分类

    Institute of Scientific and Technical Information of China (English)

    杜佳颖; 隋强强

    2011-01-01

    Aiming at the indirect correlation between the observational data and the discriminated status in traffic video event description,the relative velocity, distance and location of the vehicles on the freeway were selected as the physical quantity to be observed, and the degrees of risk of abnormal event were defined as detection status, hidden Markov learning algorithm was employed to establish event feature description model (HMM). As HMM event classification interface is nonlinear, in allusion to this, immune clone concentration clustering algorithm (ICCCA) was used for the optimised classification of normal/abnormal events, which overcame the limitation of the way directly classifying with HMM threshold, as well as the weaknesses of traditional classification algorithms such as multiple restraints and easy to falling into local optimum. Therefore, it can obtain the global optimal classification outcome accurately and quickly. 30 episodes of general video and 70 episodes of vehicle clashing video were used for testing. ROC curves and computation complexities of vehicle crashing events with HMM threshold,neural network algorithm and SVM algorithm were compared,it is shown that method proposed in this paper performed better than other classification algorithms in detecting vehicle crash events on the freeway.%针对交通视频事件描述的观测数据与判别状态的非直接关联性,以高速公路上车辆之间的相对速度、距离、位置作为观测物理量,定义异常事件的危险程度作为检测状态,利用隐马尔科夫学习算法,建立了事件特征描述模型(HMM);针对HMM事件分类界面的非线性问题,利用免疫克隆浓度聚类算法(ICCCA)对事件进行异常/正常优化分类,克服了直接利用HMM阈值分类的方法局限,以及传统分类方法约束条件多,容易陷入局部最小的缺点,能够准确快速地得到全局优化分类结果.采用30段正常视频和70段撞车视频进行测试,比较了HMM

  15. Matlab Traffic Toolbox

    Czech Academy of Sciences Publication Activity Database

    Dohnal, Pavel

    Bratislava : Slovak University of technology, 2007 - (Mikleš, J.; Fikar, M.; Kvasnica, M.), s. 1-6 ISBN 978-80-227-2677-1. [16th International Conference on Process Control. Štrbské pleso - Vysoké Tatry (SK), 11.06.2007-14.06.2007] R&D Projects: GA MŠk 1M0572; GA AV ČR 1ET100750401; GA ČR(CZ) GA102/05/0271 Institutional research plan: CEZ:AV0Z10750506 Keywords : Matlab * Traffic * Toolbox * Aimsun Subject RIV: BC - Control Systems Theory

  16. Matlab Traffic Toolbox

    Czech Academy of Sciences Publication Activity Database

    Dohnal, Pavel

    Bratislava : Slovak University of technology, 2007 - (Mikleš, J.; Fikar, M.; Kvasnica, M.) ISBN 978-80-227-2677-1. [16th International Conference on Process Control. 11.06.2007-14.06.2007, Štrbské pleso - Vysoké Tatry] R&D Projects: GA MŠk 1M0572; GA AV ČR 1ET100750401; GA ČR(CZ) GA102/05/0271 Institutional research plan: CEZ:AV0Z10750506 Keywords : Matlab * Toolbox * Aimsun * Traffic Subject RIV: BC - Control Systems Theory

  17. Dynamic route guidance strategy in a two-route pedestrian-vehicle mixed traffic flow system

    Science.gov (United States)

    Liu, Mianfang; Xiong, Shengwu; Li, Bixiang

    2016-05-01

    With the rapid development of transportation, traffic questions have become the major issue for social, economic and environmental aspects. Especially, during serious emergencies, it is very important to alleviate road traffic congestion and improve the efficiency of evacuation to reduce casualties, and addressing these problems has been a major task for the agencies responsible in recent decades. Advanced road guidance strategies have been developed for homogeneous traffic flows, or to reduce traffic congestion and enhance the road capacity in a symmetric two-route scenario. However, feedback strategies have rarely been considered for pedestrian-vehicle mixed traffic flows with variable velocities and sizes in an asymmetric multi-route traffic system, which is a common phenomenon in many developing countries. In this study, we propose a weighted road occupancy feedback strategy (WROFS) for pedestrian-vehicle mixed traffic flows, which considers the system equilibrium to ease traffic congestion. In order to more realistic simulating the behavior of mixed traffic objects, the paper adopted a refined and dynamic cellular automaton model (RDPV_CA model) as the update mechanism for pedestrian-vehicle mixed traffic flow. Moreover, a bounded rational threshold control was introduced into the feedback strategy to avoid some negative effect of delayed information and reduce. Based on comparisons with the two previously proposed strategies, the simulation results obtained in a pedestrian-vehicle traffic flow scenario demonstrated that the proposed strategy with a bounded rational threshold was more effective and system equilibrium, system stability were reached.

  18. CONTROLLING TRAFFIC FLOW IN MULTILANE-ISOLATED INTERSECTION USING ANFIS APPROACH TECHNIQUES

    Directory of Open Access Journals (Sweden)

    G. R. LAI

    2015-08-01

    Full Text Available Many controllers have applied the Adaptive Neural-Fuzzy Inference System (ANFIS concept for optimizing the controller performance. However, there are less traffic signal controllers developed using the ANFIS concept. ANFIS traffic signal controller with its fuzzy rule base and its ability to learn from a set of sample data could improve the performance of Existing traffic signal controlling system to reduce traffic congestions at most of the busy traffic intersections in city such as Kuala Lumpur, Malaysia. The aim of this research is to develop an ANFIS traffic signals controller for multilane-isolated four approaches intersections in order to ease traffic congestions at traffic intersections. The new concept to generate sample data for ANFIS training is introduced in this research. The sample data is generated based on fuzzy rules and can be analysed using tree diagram. This controller is simulated on multilane-isolated traffic intersection model developed using M/M/1 queuing theory and its performance in terms of average waiting time, queue length and delay time are compared with traditional controllers and fuzzy controller. Simulation result shows that the average waiting time, queue length, and delay time of ANFIS traffic signal controller are the lowest as compared to the other three controllers. In conclusion, the efficiency and performance of ANFIS controller are much better than that of fuzzy and traditional controllers in different traffic volumes.

  19. Large scale traffic simulations

    Energy Technology Data Exchange (ETDEWEB)

    Nagel, K.; Barrett, C.L. [Los Alamos National Lab., NM (United States)]|[Santa Fe Institute, NM (United States); Rickert, M. [Los Alamos National Lab., NM (United States)]|[Universitaet zu Koeln (Germany)

    1997-04-01

    Large scale microscopic (i.e. vehicle-based) traffic simulations pose high demands on computational speed in at least two application areas: (i) real-time traffic forecasting, and (ii) long-term planning applications (where repeated {open_quotes}looping{close_quotes} between the microsimulation and the simulated planning of individual person`s behavior is necessary). As a rough number, a real-time simulation of an area such as Los Angeles (ca. 1 million travellers) will need a computational speed of much higher than 1 million {open_quotes}particle{close_quotes} (= vehicle) updates per second. This paper reviews how this problem is approached in different projects and how these approaches are dependent both on the specific questions and on the prospective user community. The approaches reach from highly parallel and vectorizable, single-bit implementations on parallel supercomputers for Statistical Physics questions, via more realistic implementations on coupled workstations, to more complicated driving dynamics implemented again on parallel supercomputers. 45 refs., 9 figs., 1 tab.

  20. Fastlane: Traffic flow modeling and multi-class dynamic traffic management

    OpenAIRE

    Schreiter, T.; Van Wageningen-Kessels, F.L.M.; Yuan, Y; Lint, van J. W. C.; Hoogendoorn, S.P.

    2012-01-01

    Dynamic Traffic Management (DTM) aims to improve traffic conditions. DTM usually consists of two steps: first the current traffic is estimated, then appropriate control actions are determined based on that estimate. In order to estimate and control the traffic, a suitable traffic flow model that reproduces the properties of traffic well must be used. One of the most important properties is that traffic is composed of multiple vehicle classes. While many traffic flow models have been proposed ...

  1. Heterogeneous Deployment to Meet Traffic Demand in a Realistic LTE Urban Scenario

    DEFF Research Database (Denmark)

    Coletti, Claudio; Hu, Liang; Nguyen, Huan Cong;

    2012-01-01

    growth of mo-bile broadband traffic. Emphasis is put on how to optimally as-sign the spectrum for the different networks layers in an evolved HetNet including outdoor and indoor small cells. The study is conducted for a “Hot-Zone” scenario, i.e. a high-traffic area within a realistic dense urban...

  2. Refractive outcomes of an advanced aspherically optimized profile for myopia corrections by LASIK: a retrospective comparison with the standard aspherically optimized profile

    OpenAIRE

    Meyer B; Sluyterman van Langeweyde G; Wottke M

    2015-01-01

    Bertram Meyer,1 Georg Sluyterman van Langeweyde,2 Matthias Wottke2 1Augencentrum Köln, Cologne, Germany; 2Carl Zeiss Meditec AG, Jena, Germany Purpose: A retrospective comparison of refractive outcomes of a new, aspherically optimized profile with an enhanced energy correction feature (Triple-A) and the conventionally used aspherically optimized profile (ASA, or aberration smart ablation) for correction of low-to-high myopia.Setting: Augen-OP-Centrum, Cologne, GermanyDesign: Retrospect...

  3. Speed limit and ramp meter control for traffic flow networks

    Science.gov (United States)

    Goatin, Paola; Göttlich, Simone; Kolb, Oliver

    2016-07-01

    The control of traffic flow can be related to different applications. In this work, a method to manage variable speed limits combined with coordinated ramp metering within the framework of the Lighthill-Whitham-Richards (LWR) network model is introduced. Following a 'first-discretize-then-optimize' approach, the first order optimality system is derived and the switch of speeds at certain fixed points in time is explained, together with the boundary control for the ramp metering. Sequential quadratic programming methods are used to solve the control problem numerically. For application purposes, experimental setups are presented wherein variable speed limits are used as a traffic guidance system to avoid traffic jams on highway interchanges and on-ramps.

  4. Statistical modelling of traffic safety development

    DEFF Research Database (Denmark)

    Christens, Peter

    2004-01-01

    there were 6861 injury trafficc accidents reported by the police, resulting in 4519 minor injuries, 3946 serious injuries, and 431 fatalities. The general purpose of the research was to improve the insight into aggregated road safety methodology in Denmark. The aim was to analyse advanced statistical...... methods, that were designed to study developments over time, including effects of interventions. This aim has been achieved by investigating variations in aggregated Danish traffic accident series and by applying state of the art methodologies to specific case studies. The thesis comprises an introduction...

  5. Traffic dynamics on coupled spatial networks

    International Nuclear Information System (INIS)

    With the rapid development of modern traffic, various means of transportation systems make it more convenient and diversified for passengers to travel out. In this paper, we establish a two-layered spatial network model where the low-speed lower layer is a regular lattice and the high-speed upper layer is a scale-free network embedded in the lattice. Passengers will travel along the path with the minimal travel time, and they can transfer from one layer to the other, which will induce extra transfer cost. We extensively investigate the traffic process on these coupled spatial networks and focus on the effect of the parameter α, the speed ratio between two networks. It is found that, as α grows, the network capacity of the coupled networks increases in the early stage and then decreases, indicating that cooperation between the coupled networks will induce the highest network capacity at an optimal α. We then provide an explanation for this non-monotonous dependence from a micro-scope point of view. The travel time reliability is also examined. Both in free-flow state and congestion state, the travel time is linearly related to the Euclidean distance. However, the variance of travel time in the congestion state is remarkably larger than that in the free-flow state, namely, people have to set aside more redundant time in an unreliable traffic system

  6. Simulation Study of a Traffic Light Assistant Based on Vehicle-Infrastructure Communication

    CERN Document Server

    Treiber, Martin

    2014-01-01

    Vehicle-infrastructure communication opens up new ways to improve traffic flow efficiency at signalized intersections. In this study, we assume that equipped vehicles can obtain information about switching times of relevant traffic lights in advance, and additionally counting data from upstream detectors. By means of simulation, we investigate, how equipped vehicles can make use of this information to improve traffic flow. Criteria include cycle-averaged capacity, driving comfort, fuel consumption, travel time, and the number of stops. Depending on the overall traffic demand and the penetration rate of equipped vehicles, we generally find several percent of improvement.

  7. Traffic flow modeling: a Genealogy

    NARCIS (Netherlands)

    Van Wageningen-Kessels, F.L.M.; Hoogendoorn, S.P.; Vuik, C.; Van Lint, J.W.C.

    2014-01-01

    80 years ago, Bruce Greenshields presented the first traffic flow model at the Annual Meeting of the Highway Research Board. Since then, many models and simulation tools have been developed. We show a model tree with four families of traffic flow models, all descending from Greenshields' model. The

  8. Probabilistic description of traffic flow

    International Nuclear Information System (INIS)

    A stochastic description of traffic flow, called probabilistic traffic flow theory, is developed. The general master equation is applied to relatively simple models to describe the formation and dissolution of traffic congestions. Our approach is mainly based on spatially homogeneous systems like periodically closed circular rings without on- and off-ramps. We consider a stochastic one-step process of growth or shrinkage of a car cluster (jam). As generalization we discuss the coexistence of several car clusters of different sizes. The basic problem is to find a physically motivated ansatz for the transition rates of the attachment and detachment of individual cars to a car cluster consistent with the empirical observations in real traffic. The emphasis is put on the analogy with first-order phase transitions and nucleation phenomena in physical systems like supersaturated vapour. The results are summarized in the flux-density relation, the so-called fundamental diagram of traffic flow, and compared with empirical data. Different regimes of traffic flow are discussed: free flow, congested mode as stop-and-go regime, and heavy viscous traffic. The traffic breakdown is studied based on the master equation as well as the Fokker-Planck approximation to calculate mean first passage times or escape rates. Generalizations are developed to allow for on-ramp effects. The calculated flux-density relation and characteristic breakdown times coincide with empirical data measured on highways. Finally, a brief summary of the stochastic cellular automata approach is given

  9. Road traffic noise and stroke

    DEFF Research Database (Denmark)

    Sørensen, Mette; Hvidberg, Martin; Andersen, Zorana J;

    2011-01-01

    Epidemiological studies suggest that long-term exposure to road traffic noise increases the risk of cardiovascular disorders. The aim of this study was to investigate the relation between exposure to road traffic noise and risk for stroke, which has not been studied before....

  10. Traffic Light Controller Using Fpga

    Directory of Open Access Journals (Sweden)

    D.Bhavana

    2015-04-01

    Full Text Available The traffic light sequence works on the specific switching of Red, Green and Yellow lights in a particular way with stipulated time form. The normal function of traffic lights requires sophisticated control and coordination to ensure that traffic moves as smoothly and safely as possible and that pedestrians are protected when they cross the roads [1] .This Traffic Light sequence is generated using a specific switching mechanism which will help to control a traffic light system on a road in a specified sequence. This paper focuses on the fact that the traffic lights can be varied in the day and night mode depending on the intensity of the traffic. It plays a vital role in supervising and running the metropolitan traffic and evade the possibilities of any unfortunate mishaps happening in and around the cities. It is a sequential machine to be scrutinized as per the requirements and programmed through a multistep development process. The methods that are used in this project are proposing the circuit, write a code, simulate, synthesis and implement on the hardware [8] . In this project, XILINX Software was chosen to devise a schematic using schematic edit, write a code using Verilog HDL (Hardware Description Language text editor and implements the circuit on Programmable Logic Device [PLD].The system has been successfully tested and implemented in hardware using Nexys 2 Digilent FPGA.

  11. Dissociative Tendencies and Traffic Incidents

    Directory of Open Access Journals (Sweden)

    Valle, Virginia

    2012-01-01

    Full Text Available This paper analyses the relationship between dissociative experiences and road traffic incidents (crashes and traffic tickets in drivers (n=295 from Mar del Plata (Argentina city. A self-report questionnaire was applied to assess traffic crash involvement and sociodemographic variables. Dissociative tendencies were assessed by a modified version of the DES scale. To examine differences in DES scores tests of the difference of means were applied. Drivers who reported to be previously involved in traffic incidents obtained higher puntuations in the dissociative experiences scale than drivers who did not report such events. This result is observed for the total scale and for the three sub-scales (absorption, amnesia and depersonalization. However, differences appeared mainly for minor damage collisions. Further studies are needed to evaluate the role of dissociative tendencies as a risk factor in road traffic safety.

  12. Basic model for traffic interweave

    Science.gov (United States)

    Huang, Ding-wei

    2015-09-01

    We propose a three-parameter traffic model. The system consists of a loop with two junctions. The three parameters control the inflow, the outflow (from the junctions,) and the interweave (in the loop.) The dynamics is deterministic. The boundary conditions are stochastic. We present preliminary results for a complete phase diagram and all possible phase transitions. We observe four distinct traffic phases: free flow, congestion, bottleneck, and gridlock. The proposed model is able to present economically a clear perspective to these four different phases. Free flow and congestion are caused by the traffic conditions in the junctions. Both bottleneck and gridlock are caused by the traffic interweave in the loop. Instead of directly related to conventional congestion, gridlock can be taken as an extreme limit of bottleneck. This model can be useful to clarify the characteristics of traffic phases. This model can also be extended for practical applications.

  13. A Time Series Modeling and Prediction of Wireless Network Traffic

    Directory of Open Access Journals (Sweden)

    S. Gowrishankar

    2009-01-01

    Full Text Available The number of users and their network utilization will enumerate the traffic of the network. The accurate and timely estimation of network traffic is increasingly becoming important in achieving guaranteed Quality of Service (QoS in a wireless network. The better QoS can be maintained in the network by admission control, inter or intra network handovers by knowing the network traffic in advance. Here wireless network traffic is modeled as a nonlinear and nonstationary time series. In this framework, network traffic is predicted using neural network and statistical methods. The results of both the methods are compared on different time scales or time granularity. The Neural Network(NN architectures used in this study are Recurrent Radial Basis Function Network (RRBFN and Echo state network (ESN.The statistical model used here in this work is Fractional Auto Regressive Integrated Moving Average (FARIMA model. The traffic prediction accuracy of neural network and statistical models are in the range of 96.4% to 98.3% and 78.5% to 80.2% respectively.

  14. Counter-based Traffic Management Scheme for Vehicular Networks

    Directory of Open Access Journals (Sweden)

    Tarun Prakash

    2011-06-01

    Full Text Available Vehicles traffic congestion on the road is reflected as delays while traveling. This congestion has a number of negative effects such as energy consumption, wastage of time and increased tailpipes emission of idling vehicles probably bad for our health. Vehicular congestion has become the serious problem and it is getting worse day by day as the growth of the vehicles significantly increased. In this paper, we proposed a novel counter approach to avoid such vehicular congestion on the road. We have also proposed a path selection algorithm that ensures best path suggestion to vehicles in terms of reduction in trip time and less fuel consumption during whole trip. The whole traffic management solution is combination of "stochastic turn" (i.e. vehicles choose a new direction at each intersection or any other way point and path planning (i.e. origin and destination of the vehicle required in advance that ensured by suggested path selection algorithm. In the later part of this paper simulation results prove the effectiveness of our traffic management scheme in terms of reducing traffic congestion on the road. In addition, this scheme utilizes best of the resources and characteristics of vehicular networks to provide less congested path prediction and also smoothed flow of traffic for vehicles in high density vehicular traffic conditions.

  15. Traffic Impact Simulation for Road Construction Project

    OpenAIRE

    Yazao Yang; Xiaoni Hao; Junshao Luo

    2012-01-01

    With the increasing traffic contradiction between supply and demand, urban traffic problems have become quite complex. Reasons for traffic congestion have become much more diverse. During the construction of urban road project, the surrounding road network will encounter a huge impact, traffic problems therefore emerged. Simulation is an important means for transport impact assessment, which has an important role for construction traffic impact analysis. Accordingly, traffic simulation i...

  16. An Open-Source Microscopic Traffic Simulator

    OpenAIRE

    Treiber, Martin; Kesting, Arne

    2010-01-01

    We present the interactive Java-based open-source traffic simulator available at www.traffic-simulation.de. In contrast to most closed-source commercial simulators, the focus is on investigating fundamental issues of traffic dynamics rather than simulating specific road networks. This includes testing theories for the spatiotemporal evolution of traffic jams, comparing and testing different microscopic traffic models, modeling the effects of driving styles and traffic rules on the efficiency ...

  17. Traffic Matrix Reloaded: Impact of Routing Changes

    OpenAIRE

    Teixeira, Renata; Duffield, Nick; Rexford, Jennifer; Roughan, Matthew

    2005-01-01

    International audience A traffic matrix represents the load from each ingress point to each egress point in an IP network. Although networks are engineered to tolerate some variation in the traffic matrix, large changes can lead to congested links and poor performance. The variations in the traffic matrix are caused by statistical fluc-tuations in the traffic entering the network and shifts in where the traffic leaves the network. For an accurate view of how the traffic matrix evolves over...

  18. Simulation of Genetic Algorithm: Traffic Light Efficiency

    OpenAIRE

    Lienert, Eric

    2015-01-01

    Traffic is a problem in many urban areas worldwide. Traffic flow is dictated by certain devices such as traffic lights. The traffic lights signal when each lane is able to pass through the intersection. Often, static schedules interfere with ideal traffic flow. The purpose of this project was to find a way to make intersections controlled with traffic lights more efficient. This goal was accomplished through the creation of a genetic algorithm, which enhances an input algorithm through geneti...

  19. Integrated Traffic Flow Management Decision Making

    Science.gov (United States)

    Grabbe, Shon R.; Sridhar, Banavar; Mukherjee, Avijit

    2009-01-01

    A generalized approach is proposed to support integrated traffic flow management decision making studies at both the U.S. national and regional levels. It can consider tradeoffs between alternative optimization and heuristic based models, strategic versus tactical flight controls, and system versus fleet preferences. Preliminary testing was accomplished by implementing thirteen unique traffic flow management models, which included all of the key components of the system and conducting 85, six-hour fast-time simulation experiments. These experiments considered variations in the strategic planning look-ahead times, the replanning intervals, and the types of traffic flow management control strategies. Initial testing indicates that longer strategic planning look-ahead times and re-planning intervals result in steadily decreasing levels of sector congestion for a fixed delay level. This applies when accurate estimates of the air traffic demand, airport capacities and airspace capacities are available. In general, the distribution of the delays amongst the users was found to be most equitable when scheduling flights using a heuristic scheduling algorithm, such as ration-by-distance. On the other hand, equity was the worst when using scheduling algorithms that took into account the number of seats aboard each flight. Though the scheduling algorithms were effective at alleviating sector congestion, the tactical rerouting algorithm was the primary control for avoiding en route weather hazards. Finally, the modeled levels of sector congestion, the number of weather incursions, and the total system delays, were found to be in fair agreement with the values that were operationally observed on both good and bad weather days.

  20. The choice of optimal radiotherapy technique for locally advanced maxillary carcinoma using 3d treatment planning system

    Directory of Open Access Journals (Sweden)

    Mileusnić Dušan

    2004-01-01

    Full Text Available Aim. To compare the isodose distribution of three radiotherapy techniques for locally advanced maxillary sinus carcinoma and analyze the potential of three-dimensional (3D conformal radiotherapy planning in order to determine the optimal technique for target dose delivery, and spare uninvolved healthy tissue structures. Methods. Computed tomography (CT scans of fourteen patients with T3-T4, N0, M0 maxillary sinus carcinoma were acquired and transferred to 3D treatment planning system (3D-TPS. The target volume and uninvolved dose limiting structures were contoured on axial CT slices throughout the volume of interest combining three variants of treatment plans (techniques for each patient: 1. A conventional two-dimensional (2D treatment plan with classically shaped one anterior two lateral opposite fields and two types of 3D conformal radiotherapy plans were compared for each patient. 2. Three-dimensional standard (3D-S plan one anterior + two lateral opposite coplanar fields, which outlines were shaped with multileaf collimator (MLC according to geometric information based on 3D reconstruction of target volume and organs at risk as seen in the beam eye's view (BEV projection. 3. Three-dimensional non-standard (3D-NS plan: one anterior + two lateral noncoplanar fields, which outlines were shaped in the same manner as in 3D-S plans. The planning parameters for target volumes and the degree of neurooptic structures and parotid glands protection were evaluated for all three techniques. Comparison of plans and treatment techniques was assessed by isodose distribution, dose statistics and dose-volume histograms. Results. The most enhanced conformity of the dose delivered to the target volume was achieved with 3D-NS technique, and significant differences were found comparing 3D-NS vs. 2D (Dmax: p<0,05 Daver: p<0,01; Dmin: p<0,05; V90: p<0,05, and V95: p<0,01, as well as 3D-NS vs. 3D-S technique (Dmin: p<0,05; V90: p<0,05, and V95: p<0,01, while there