Vehicle routing with stochastic time-dependent travel times

NARCIS (Netherlands)

Lecluyse, C.; Woensel, van T.; Peremans, H.

2009-01-01

Assigning and scheduling vehicle routes in a stochastic time-dependent environment is a crucial management problem. The assumption that in a real-life environment everything goes according to an a priori determined static schedule is unrealistic. Our methodology builds on earlier work in which the

Vehicle routing with stochastic time-dependent travel times

NARCIS (Netherlands)

Lecluyse, C.; Woensel, van T.; Peremans, H.

2007-01-01

Assigning and scheduling vehicle routes in a stochastic time-dependent environment is a crucial management problem. The assumption that in a real-life environment everything goes according to an a priori determined static schedule is unrealistic. Our methodology builds on earlier work in which the

Physics constrained nonlinear regression models for time series

International Nuclear Information System (INIS)

Majda, Andrew J; Harlim, John

2013-01-01

A central issue in contemporary science is the development of data driven statistical nonlinear dynamical models for time series of partial observations of nature or a complex physical model. It has been established recently that ad hoc quadratic multi-level regression (MLR) models can have finite-time blow up of statistical solutions and/or pathological behaviour of their invariant measure. Here a new class of physics constrained multi-level quadratic regression models are introduced, analysed and applied to build reduced stochastic models from data of nonlinear systems. These models have the advantages of incorporating memory effects in time as well as the nonlinear noise from energy conserving nonlinear interactions. The mathematical guidelines for the performance and behaviour of these physics constrained MLR models as well as filtering algorithms for their implementation are developed here. Data driven applications of these new multi-level nonlinear regression models are developed for test models involving a nonlinear oscillator with memory effects and the difficult test case of the truncated Burgers–Hopf model. These new physics constrained quadratic MLR models are proposed here as process models for Bayesian estimation through Markov chain Monte Carlo algorithms of low frequency behaviour in complex physical data. (paper)

Evolutionary algorithms for the Vehicle Routing Problem with Time Windows

NARCIS (Netherlands)

Bräysy, Olli; Dullaert, Wout; Gendreau, Michel

2004-01-01

This paper surveys the research on evolutionary algorithms for the Vehicle Routing Problem with Time Windows (VRPTW). The VRPTW can be described as the problem of designing least cost routes from a single depot to a set of geographically scattered points. The routes must be designed in such a way

Time-constrained project scheduling with adjacent resources

NARCIS (Netherlands)

Hurink, Johann L.; Kok, A.L.; Paulus, J.J.; Schutten, Johannes M.J.

We develop a decomposition method for the Time-Constrained Project Scheduling Problem (TCPSP) with adjacent resources. For adjacent resources the resource units are ordered and the units assigned to a job have to be adjacent. On top of that, adjacent resources are not required by single jobs, but by

Time-constrained project scheduling with adjacent resources

NARCIS (Netherlands)

Hurink, Johann L.; Kok, A.L.; Paulus, J.J.; Schutten, Johannes M.J.

2008-01-01

We develop a decomposition method for the Time-Constrained Project Scheduling Problem (TCPSP) with Adjacent Resources. For adjacent resources the resource units are ordered and the units assigned to a job have to be adjacent. On top of that, adjacent resources are not required by single jobs, but by

An Evolutionary Real-Time 3D Route Planner for Aircraft

Institute of Scientific and Technical Information of China (English)

郑昌文; 丁明跃; 周成平

2003-01-01

A novel evolutionary route planner for aircraft is proposed in this paper. In the new planner, individual candidates are evaluated with respect to the workspace, thus the computation of the configuration space is not required. By using problem-specific chromosome structure and genetic operators, the routes are generated in real time,with different mission constraints such as minimum route leg length and flying altitude, maximum turning angle, maximum climbing/diving angle and route distance constraint taken into account.

Stochastic skyline route planning under time-varying uncertainty

DEFF Research Database (Denmark)

Yang, Bin; Guo, Chenjuan; Jensen, Christian S.

2014-01-01

Different uses of a road network call for the consideration of different travel costs: in route planning, travel time and distance are typically considered, and green house gas (GHG) emissions are increasingly being considered. Further, travel costs such as travel time and GHG emissions are time...

Stochastic time-dependent vehicle routing problem: Mathematical models and ant colony algorithm

Directory of Open Access Journals (Sweden)

Zhengyu Duan

2015-11-01

Full Text Available This article addresses the stochastic time-dependent vehicle routing problem. Two mathematical models named robust optimal schedule time model and minimum expected schedule time model are proposed for stochastic time-dependent vehicle routing problem, which can guarantee delivery within the time windows of customers. The robust optimal schedule time model only requires the variation range of link travel time, which can be conveniently derived from historical traffic data. In addition, the robust optimal schedule time model based on robust optimization method can be converted into a time-dependent vehicle routing problem. Moreover, an ant colony optimization algorithm is designed to solve stochastic time-dependent vehicle routing problem. As the improvements in initial solution and transition probability, ant colony optimization algorithm has a good performance in convergence. Through computational instances and Monte Carlo simulation tests, robust optimal schedule time model is proved to be better than minimum expected schedule time model in computational efficiency and coping with the travel time fluctuations. Therefore, robust optimal schedule time model is applicable in real road network.

Pithy Review on Routing Protocols in Wireless Sensor Networks and Least Routing Time Opportunistic Technique in WSN

Science.gov (United States)

Salman Arafath, Mohammed; Rahman Khan, Khaleel Ur; Sunitha, K. V. N.

2018-01-01

Nowadays due to most of the telecommunication standard development organizations focusing on using device-to-device communication so that they can provide proximity-based services and add-on services on top of the available cellular infrastructure. An Oppnets and wireless sensor network play a prominent role here. Routing in these networks plays a significant role in fields such as traffic management, packet delivery etc. Routing is a prodigious research area with diverse unresolved issues. This paper firstly focuses on the importance of Opportunistic routing and its concept then focus is shifted to prime aspect i.e. on packet reception ratio which is one of the highest QoS Awareness parameters. This paper discusses the two important functions of routing in wireless sensor networks (WSN) namely route selection using least routing time algorithm (LRTA) and data forwarding using clustering technique. Finally, the simulation result reveals that LRTA performs relatively better than the existing system in terms of average packet reception ratio and connectivity.

Reliable Rescue Routing Optimization for Urban Emergency Logistics under Travel Time Uncertainty

Directory of Open Access Journals (Sweden)

Qiuping Li

2018-02-01

Full Text Available The reliability of rescue routes is critical for urban emergency logistics during disasters. However, studies on reliable rescue routing under stochastic networks are still rare. This paper proposes a multiobjective rescue routing model for urban emergency logistics under travel time reliability. A hybrid metaheuristic integrating ant colony optimization (ACO and tabu search (TS was designed to solve the model. An experiment optimizing rescue routing plans under a real urban storm event, was carried out to validate the proposed model. The experimental results showed how our approach can improve rescue efficiency with high travel time reliability.

Time-adaptive and history-adaptive multicriterion routing in stochastic, time-dependent networks

DEFF Research Database (Denmark)

Pretolani, Daniele; Nielsen, Lars Relund; Andersen, Kim Allan

2009-01-01

We compare two different models for multicriterion routing in stochastic time-dependent networks: the classic "time-adaptive'' model and the more flexible "history-adaptive'' one. We point out several properties of the sets of efficient solutions found under the two models. We also devise a method...

Optimal routing of hazardous substances in time-varying, stochastic transportation networks

International Nuclear Information System (INIS)

Woods, A.L.; Miller-Hooks, E.; Mahmassani, H.S.

1998-07-01

This report is concerned with the selection of routes in a network along which to transport hazardous substances, taking into consideration several key factors pertaining to the cost of transport and the risk of population exposure in the event of an accident. Furthermore, the fact that travel time and the risk measures are not constant over time is explicitly recognized in the routing decisions. Existing approaches typically assume static conditions, possibly resulting in inefficient route selection and unnecessary risk exposure. The report described the application of recent advances in network analysis methodologies to the problem of routing hazardous substances. Several specific problem formulations are presented, reflecting different degrees of risk aversion on the part of the decision-maker, as well as different possible operational scenarios. All procedures explicitly consider travel times and travel costs (including risk measures) to be stochastic time-varying quantities. The procedures include both exact algorithms, which may require extensive computational effort in some situations, as well as more efficient heuristics that may not guarantee a Pareto-optimal solution. All procedures are systematically illustrated for an example application using the Texas highway network, for both normal and incident condition scenarios. The application illustrates the trade-offs between the information obtained in the solution and computational efficiency, and highlights the benefits of incorporating these procedures in a decision-support system for hazardous substance shipment routing decisions

The Linehaul-Feeder Vehicle Routing Problem with Virtual Depots and Time Windows

Directory of Open Access Journals (Sweden)

Huey-Kuo Chen

2011-01-01

Full Text Available This paper addresses the linehaul-feeder vehicle routing problem with virtual depots and time windows (LFVRPTW. Small and large vehicles deliver services to customers within time constraints; small vehicles en route may reload commodities from either the physical depot or from the larger vehicle at a virtual depot before continuing onward. A two-stage solution heuristic involving Tabu search is proposed to solve this problem. The test results show that the LFVRPTW performs better than the vehicle routing problem with time windows in terms of both objective value and the number of small vehicles dispatched.

A two-hop based adaptive routing protocol for real-time wireless sensor networks.

Science.gov (United States)

Rachamalla, Sandhya; Kancherla, Anitha Sheela

2016-01-01

One of the most important and challenging issues in wireless sensor networks (WSNs) is to optimally manage the limited energy of nodes without degrading the routing efficiency. In this paper, we propose an energy-efficient adaptive routing mechanism for WSNs, which saves energy of nodes by removing the much delayed packets without degrading the real-time performance of the used routing protocol. It uses the adaptive transmission power algorithm which is based on the attenuation of the wireless link to improve the energy efficiency. The proposed routing mechanism can be associated with any geographic routing protocol and its performance is evaluated by integrating with the well known two-hop based real-time routing protocol, PATH and the resulting protocol is energy-efficient adaptive routing protocol (EE-ARP). The EE-ARP performs well in terms of energy consumption, deadline miss ratio, packet drop and end-to-end delay.

A Linear Programming Approach to Routing Control in Networks of Constrained Nonlinear Positive Systems with Concave Flow Rates

Science.gov (United States)

Arneson, Heather M.; Dousse, Nicholas; Langbort, Cedric

2014-01-01

We consider control design for positive compartmental systems in which each compartment's outflow rate is described by a concave function of the amount of material in the compartment.We address the problem of determining the routing of material between compartments to satisfy time-varying state constraints while ensuring that material reaches its intended destination over a finite time horizon. We give sufficient conditions for the existence of a time-varying state-dependent routing strategy which ensures that the closed-loop system satisfies basic network properties of positivity, conservation and interconnection while ensuring that capacity constraints are satisfied, when possible, or adjusted if a solution cannot be found. These conditions are formulated as a linear programming problem. Instances of this linear programming problem can be solved iteratively to generate a solution to the finite horizon routing problem. Results are given for the application of this control design method to an example problem. Key words: linear programming; control of networks; positive systems; controller constraints and structure.

Invariant set computation for constrained uncertain discrete-time systems

NARCIS (Netherlands)

Athanasopoulos, N.; Bitsoris, G.

2010-01-01

In this article a novel approach to the determination of polytopic invariant sets for constrained discrete-time linear uncertain systems is presented. First, the problem of stabilizing a prespecified initial condition set in the presence of input and state constraints is addressed. Second, the

Real-Time QoS Routing Protocols in Wireless Multimedia Sensor Networks: Study and Analysis.

Science.gov (United States)

Alanazi, Adwan; Elleithy, Khaled

2015-09-02

Many routing protocols have been proposed for wireless sensor networks. These routing protocols are almost always based on energy efficiency. However, recent advances in complementary metal-oxide semiconductor (CMOS) cameras and small microphones have led to the development of Wireless Multimedia Sensor Networks (WMSN) as a class of wireless sensor networks which pose additional challenges. The transmission of imaging and video data needs routing protocols with both energy efficiency and Quality of Service (QoS) characteristics in order to guarantee the efficient use of the sensor nodes and effective access to the collected data. Also, with integration of real time applications in Wireless Senor Networks (WSNs), the use of QoS routing protocols is not only becoming a significant topic, but is also gaining the attention of researchers. In designing an efficient QoS routing protocol, the reliability and guarantee of end-to-end delay are critical events while conserving energy. Thus, considerable research has been focused on designing energy efficient and robust QoS routing protocols. In this paper, we present a state of the art research work based on real-time QoS routing protocols for WMSNs that have already been proposed. This paper categorizes the real-time QoS routing protocols into probabilistic and deterministic protocols. In addition, both categories are classified into soft and hard real time protocols by highlighting the QoS issues including the limitations and features of each protocol. Furthermore, we have compared the performance of mobility-aware query based real-time QoS routing protocols from each category using Network Simulator-2 (NS2). This paper also focuses on the design challenges and future research directions as well as highlights the characteristics of each QoS routing protocol.

Partial path column generation for the vehicle routing problem with time windows

DEFF Research Database (Denmark)

Petersen, Bjørn; Jepsen, Mads Kehlet

2009-01-01

This paper presents a column generation algorithm for the Vehicle Routing Problem with Time Windows (VRPTW). Traditionally, column generation models of the VRPTW have consisted of a Set Partitioning master problem with each column representing a route, i.e., a resource feasible path starting...... and ending at the depot. Elementary routes (no customer visited more than once) have shown superior results on difficult instances (less restrictive capacity and time windows). However, the pricing problems do not scale well when the number of feasible routes increases, i.e., when a route may contain a large...... number of customers. We suggest to relax that ‘each column is a route’ into ‘each column is a part of the giant tour’; a so-called partial path, i.e., not necessarily starting and ending in the depot. This way, the length of the partial path can be bounded and a better control of the size of the solution...

Dynamic Bus Travel Time Prediction Models on Road with Multiple Bus Routes.

Science.gov (United States)

Bai, Cong; Peng, Zhong-Ren; Lu, Qing-Chang; Sun, Jian

2015-01-01

Accurate and real-time travel time information for buses can help passengers better plan their trips and minimize waiting times. A dynamic travel time prediction model for buses addressing the cases on road with multiple bus routes is proposed in this paper, based on support vector machines (SVMs) and Kalman filtering-based algorithm. In the proposed model, the well-trained SVM model predicts the baseline bus travel times from the historical bus trip data; the Kalman filtering-based dynamic algorithm can adjust bus travel times with the latest bus operation information and the estimated baseline travel times. The performance of the proposed dynamic model is validated with the real-world data on road with multiple bus routes in Shenzhen, China. The results show that the proposed dynamic model is feasible and applicable for bus travel time prediction and has the best prediction performance among all the five models proposed in the study in terms of prediction accuracy on road with multiple bus routes.

Dynamic Bus Travel Time Prediction Models on Road with Multiple Bus Routes

Science.gov (United States)

Bai, Cong; Peng, Zhong-Ren; Lu, Qing-Chang; Sun, Jian

2015-01-01

Accurate and real-time travel time information for buses can help passengers better plan their trips and minimize waiting times. A dynamic travel time prediction model for buses addressing the cases on road with multiple bus routes is proposed in this paper, based on support vector machines (SVMs) and Kalman filtering-based algorithm. In the proposed model, the well-trained SVM model predicts the baseline bus travel times from the historical bus trip data; the Kalman filtering-based dynamic algorithm can adjust bus travel times with the latest bus operation information and the estimated baseline travel times. The performance of the proposed dynamic model is validated with the real-world data on road with multiple bus routes in Shenzhen, China. The results show that the proposed dynamic model is feasible and applicable for bus travel time prediction and has the best prediction performance among all the five models proposed in the study in terms of prediction accuracy on road with multiple bus routes. PMID:26294903

Routing Cooperating Vehicles to Perform Precedence-Linked Tasks

National Research Council Canada - National Science Library

Vakhutinsky, Andrew; Wu, Cynara

2005-01-01

The problem of scheduling cooperating vehicles is a generalization of the classical vehicle routing problem where certain tasks are linked by precedence constraints and vehicles have varying constrained resources...

Simulated annealing (SA to vehicle routing problems with soft time windows

Directory of Open Access Journals (Sweden)

Suphan Sodsoon

2014-12-01

Full Text Available The researcher has applied and develops the meta-heuristics method to solve Vehicle Routing Problems with Soft Time Windows (VRPSTW. For this case there was only one depot, multi customers which each generally sparse either or demand was different though perceived number of demand and specific period of time to receive them. The Operation Research was representative combinatorial optimization problems and is known to be NP-hard. In this research algorithm, use Simulated Annealing (SA to determine the optimum solutions which rapidly time solving. After developed the algorithms, apply them to examine the factors and the optimum extended time windows and test these factors with vehicle problem routing under specific time windows by Solomon in OR-Library in case of maximum 25 customers. Meanwhile, 6 problems are including of C101, C102, R101, R102, RC101 and RC102 respectively. The result shows the optimum extended time windows at level of 50%. At last, after comparison these answers with the case of vehicle problem routing under specific time windows and flexible time windows, found that percentage errors on number of vehicles approximately by -28.57% and percentage errors on distances approximately by -28.57% which this algorithm spent average processing time on 45.5 sec/problems.

A New Continuous-Time Equality-Constrained Optimization to Avoid Singularity.

Science.gov (United States)

Quan, Quan; Cai, Kai-Yuan

2016-02-01

In equality-constrained optimization, a standard regularity assumption is often associated with feasible point methods, namely, that the gradients of constraints are linearly independent. In practice, the regularity assumption may be violated. In order to avoid such a singularity, a new projection matrix is proposed based on which a feasible point method to continuous-time, equality-constrained optimization is developed. First, the equality constraint is transformed into a continuous-time dynamical system with solutions that always satisfy the equality constraint. Second, a new projection matrix without singularity is proposed to realize the transformation. An update (or say a controller) is subsequently designed to decrease the objective function along the solutions of the transformed continuous-time dynamical system. The invariance principle is then applied to analyze the behavior of the solution. Furthermore, the proposed method is modified to address cases in which solutions do not satisfy the equality constraint. Finally, the proposed optimization approach is applied to three examples to demonstrate its effectiveness.

Constraining Alternative Theories of Gravity Using Pulsar Timing Arrays

Science.gov (United States)

Cornish, Neil J.; O'Beirne, Logan; Taylor, Stephen R.; Yunes, Nicolás

2018-05-01

The opening of the gravitational wave window by ground-based laser interferometers has made possible many new tests of gravity, including the first constraints on polarization. It is hoped that, within the next decade, pulsar timing will extend the window by making the first detections in the nanohertz frequency regime. Pulsar timing offers several advantages over ground-based interferometers for constraining the polarization of gravitational waves due to the many projections of the polarization pattern provided by the different lines of sight to the pulsars, and the enhanced response to longitudinal polarizations. Here, we show that existing results from pulsar timing arrays can be used to place stringent limits on the energy density of longitudinal stochastic gravitational waves. However, unambiguously distinguishing these modes from noise will be very difficult due to the large variances in the pulsar-pulsar correlation patterns. Existing upper limits on the power spectrum of pulsar timing residuals imply that the amplitude of vector longitudinal (VL) and scalar longitudinal (SL) modes at frequencies of 1/year are constrained, AVL<4 ×10-16 and ASL<4 ×10-17, while the bounds on the energy density for a scale invariant cosmological background are ΩVLh2<4 ×10-11 and ΩSLh2<3 ×10-13.

Constrained choices? Linking employees' and spouses' work time to health behaviors.

Science.gov (United States)

Fan, Wen; Lam, Jack; Moen, Phyllis; Kelly, Erin; King, Rosalind; McHale, Susan

2015-02-01

There are extensive literatures on work conditions and health and on family contexts and health, but less research asking how a spouse or partners' work conditions may affect health behaviors. Drawing on the constrained choices framework, we theorized health behaviors as a product of one's own time and spouses' work time as well as gender expectations. We examined fast food consumption and exercise behaviors using survey data from 429 employees in an Information Technology (IT) division of a U.S. Fortune 500 firm and from their spouses. We found fast food consumption is affected by men's work hours-both male employees' own work hours and the hours worked by husbands of women respondents-in a nonlinear way. The groups most likely to eat fast food are men working 50 h/week and women whose husbands work 45-50 h/week. Second, exercise is better explained if work time is conceptualized at the couple, rather than individual, level. In particular, neo-traditional arrangements (where husbands work longer than their wives) constrain women's ability to engage in exercise but increase odds of men exercising. Women in couples where both partners are working long hours have the highest odds of exercise. In addition, women working long hours with high schedule control are more apt to exercise and men working long hours whose wives have high schedule flexibility are as well. Our findings suggest different health behaviors may have distinct antecedents but gendered work-family expectations shape time allocations in ways that promote men's and constrain women's health behaviors. They also suggest the need to expand the constrained choices framework to recognize that long hours may encourage exercise if both partners are looking to sustain long work hours and that work resources, specifically schedule control, of one partner may expand the choices of the other. Copyright © 2014 Elsevier Ltd. All rights reserved.

Joint optimization of green vehicle scheduling and routing problem with time-varying speeds

Science.gov (United States)

Zhang, Dezhi; Wang, Xin; Ni, Nan; Zhang, Zhuo

2018-01-01

Based on an analysis of the congestion effect and changes in the speed of vehicle flow during morning and evening peaks in a large- or medium-sized city, the piecewise function is used to capture the rules of the time-varying speed of vehicles, which are very important in modelling their fuel consumption and CO2 emission. A joint optimization model of the green vehicle scheduling and routing problem with time-varying speeds is presented in this study. Extra wages during nonworking periods and soft time-window constraints are considered. A heuristic algorithm based on the adaptive large neighborhood search algorithm is also presented. Finally, a numerical simulation example is provided to illustrate the optimization model and its algorithm. Results show that, (1) the shortest route is not necessarily the route that consumes the least energy, (2) the departure time influences the vehicle fuel consumption and CO2 emissions and the optimal departure time saves on fuel consumption and reduces CO2 emissions by up to 5.4%, and (3) extra driver wages have significant effects on routing and departure time slot decisions. PMID:29466370

On the Integrated Job Scheduling and Constrained Network Routing Problem

DEFF Research Database (Denmark)

Gamst, Mette

This paper examines the NP-hard problem of scheduling a number of jobs on a finite set of machines such that the overall profit of executed jobs is maximized. Each job demands a number of resources, which must be sent to the executing machine via constrained paths. Furthermore, two resource demand...

An algorithm for routing optimization in DiffServ-aware MPLS networks

OpenAIRE

Luigi Atzori; Fabio D'Andreagiovanni; Carlo Mannino; Tatiana Onali

2010-01-01

This paper addresses the constrained-based routing problem in DiffServaware MPLS networks. We consider a dynamic context in which new requests appear over time, asking for reconfigurations of the previous allocation. In the classical approach, a multi-phase heuristic procedure is adopted: the new requests are evaluated considering available bandwidth; if the bandwidth is not sufficient, preemption and rerouting of one or more connections are performed in sequence. As an alternative, we propos...

The time-dependent prize-collecting arc routing problem

DEFF Research Database (Denmark)

Black, Dan; Eglese, Richard; Wøhlk, Sanne

2013-01-01

with the time of day. Two metaheuristic algorithms, one based on Variable Neighborhood Search and one based on Tabu Search, are proposed and tested for a set of benchmark problems, generated from real road networks and travel time information. Both algorithms are capable of finding good solutions, though......A new problem is introduced named the Time-Dependent Prize-Collecting Arc Routing Problem (TD-PARP). It is particularly relevant to situations where a transport manager has to choose between a number of full truck load pick-ups and deliveries on a road network where travel times change...

Time Dependent Heterogeneous Vehicle Routing Problem for Catering Service Delivery Problem

Science.gov (United States)

Azis, Zainal; Mawengkang, Herman

2017-09-01

The heterogeneous vehicle routing problem (HVRP) is a variant of vehicle routing problem (VRP) which describes various types of vehicles with different capacity to serve a set of customers with known geographical locations. This paper considers the optimal service deliveries of meals of a catering company located in Medan City, Indonesia. Due to the road condition as well as traffic, it is necessary for the company to use different type of vehicle to fulfill customers demand in time. The HVRP incorporates time dependency of travel times on the particular time of the day. The objective is to minimize the sum of the costs of travelling and elapsed time over the planning horizon. The problem can be modeled as a linear mixed integer program and we address a feasible neighbourhood search approach to solve the problem.

Reachability cuts for the vehicle routing problem with time windows

DEFF Research Database (Denmark)

Lysgaard, Jens

2004-01-01

This paper introduces a class of cuts, called reachability cuts, for the Vehicle Routing Problem with Time Windows (VRPTW). Reachability cuts are closely related to cuts derived from precedence constraints in the Asymmetric Traveling Salesman Problem with Time Windows and to k-path cuts...

Dynamic call center routing policies using call waiting and agent idle times

NARCIS (Netherlands)

Chan, W.; Koole, G.M.; L'Ecuyer, P.

2014-01-01

We study call routing policies for call centers with multiple call types and multiple agent groups. We introduce new weight-based routing policies where each pair (call type, agent group) is given a matching priority defined as an affine combination of the longest waiting time for that call type and

A source-initiated on-demand routing algorithm based on the Thorup-Zwick theory for mobile wireless sensor networks.

Science.gov (United States)

Mao, Yuxin; Zhu, Ping

2013-01-01

The unreliability and dynamics of mobile wireless sensor networks make it hard to perform end-to-end communications. This paper presents a novel source-initiated on-demand routing mechanism for efficient data transmission in mobile wireless sensor networks. It explores the Thorup-Zwick theory to achieve source-initiated on-demand routing with time efficiency. It is able to find out shortest routing path between source and target in a network and transfer data in linear time. The algorithm is easy to be implemented and performed in resource-constrained mobile wireless sensor networks. We also evaluate the approach by analyzing its cost in detail. It can be seen that the approach is efficient to support data transmission in mobile wireless sensor networks.

Path inequalities for the vehicle routing problem with time windows

DEFF Research Database (Denmark)

Kallehauge, Brian; Boland, Natashia; Madsen, Oli B.G.

2007-01-01

In this paper we introduce a new formulation of the vehicle routing problem with time windows (VRPTW) involving only binary variables. The new formulation is based on the formulation of the asymmetric traveling salesman problem with time windows by Ascheuer et al. (Networks 36 (2000) 69-79) and has...

A Comprehensive Real-Time Traffic Map for Geographic Routing in VANETs

Directory of Open Access Journals (Sweden)

Chi-Fu Huang

2017-01-01

Full Text Available Vehicular Ad Hoc Networks (VANETs have attracted a lot of attention during the last decade. VANETs can not only improve driving safety, but also convenience, and support most future Intelligent Transportation System (ITS. Due to the highly dynamic network topology of VANETs, many geographic routing protocols have been proposed and use real-time traffic information as an important metric to select a reliable forwarding path. However, most of the existing works do not describe how to gather real-time traffic. They either assume this information is already available, or can query an existing traffic center. Few studies have noticed this issue but the proposed solutions only consider a small region. In this paper, we propose a Comprehensive Real-Time Traffic Map (CRT Map to collect wide-ranging real-time traffic information with low overhead. In the design of a CRT Map, the concept of Crowdsensing is adopted. Vehicles cooperatively gather traffic information and share it with each other to construct an overview of the whole road network traffic. In addition, we design a CRT Map Based Routing (CBR, which takes into account the connectivity of consecutive roads in routing decisions. Simulation results show that the CBR can achieve a lower end-to-end delay and a higher packet delivery ratio.

A Time-constrained Network Voronoi Construction and Accessibility Analysis in Location-based Service Technology

Science.gov (United States)

Yu, W.; Ai, T.

2014-11-01

Accessibility analysis usually requires special models of spatial location analysis based on some geometric constructions, such as Voronoi diagram (abbreviated to VD). There are many achievements in classic Voronoi model research, however suffering from the following limitations for location-based services (LBS) applications. (1) It is difficult to objectively reflect the actual service areas of facilities by using traditional planar VDs, because human activities in LBS are usually constrained only to the network portion of the planar space. (2) Although some researchers have adopted network distance to construct VDs, their approaches are used in a static environment, where unrealistic measures of shortest path distance based on assumptions about constant travel speeds through the network were often used. (3) Due to the computational complexity of the shortest-path distance calculating, previous researches tend to be very time consuming, especially for large datasets and if multiple runs are required. To solve the above problems, a novel algorithm is developed in this paper. We apply network-based quadrat system and 1-D sequential expansion to find the corresponding subnetwork for each focus. The idea is inspired by the natural phenomenon that water flow extends along certain linear channels until meets others or arrives at the end of route. In order to accommodate the changes in traffic conditions, the length of network-quadrat is set upon the traffic condition of the corresponding street. The method has the advantage over Dijkstra's algorithm in that the time cost is avoided, and replaced with a linear time operation.

Performance Analysis of the Enhanced DSR Routing Protocol for the Short Time Disconnected MANET to the OPNET Modeler

Directory of Open Access Journals (Sweden)

PAPAJ Ján

2013-05-01

Full Text Available Disconnected mobile ad-hoc networks (MANET are very important areas of the research. In this article, the performance analysis of the enhanced dynamic source routing protocol (OPP_DSR is introduced. This modification enables the routing process in the case when there are no connections to other mobile nodes. It also will enable the routing mechanisms when the routes, selected by routing mechanisms, are disconnected for some time. Disconnection can be for a short time and standard routing protocol DSR cannot reflect on this situation.The main idea is based on opportunistic forwarding where the nodes not only forward data but it's stored in the cache during long time. The network parameters throughput, routing load and are analysed.

Exact method for the vehicle routing problem with mixed linehaul and backhaul customers, heterogeneous fleet, time window and manufacturing capacity

OpenAIRE

Oesterle, Jonathan; Bauernhansl, Thomas

2016-01-01

Due to concerns over food safety, quality, and transparency, the food industry has been challenged to deal with an increased complexity in its logistics and production planning. This complexity is mostly associated to the task of optimally exploring a highly constrained solution space. This paper addresses the problem of designing a set of vehicle routes satisfying the delivery and the collection requirements of a set of geographically scattered linehaul and backhaul customers. Each customer ...

Application of the multi-objective cross-entropy method to the vehicle routing problem with soft time windows

Directory of Open Access Journals (Sweden)

C Hauman

2014-06-01

Full Text Available The vehicle routing problem with time windows is a widely studied problem with many real-world applications. The problem considered here entails the construction of routes that a number of identical vehicles travel to service different nodes within a certain time window. New benchmark problems with multi-objective features were recently suggested in the literature and the multi-objective optimisation cross-entropy method is applied to these problems to investigate the feasibility of the method and to determine and propose reference solutions for the benchmark problems. The application of the cross-entropy method to the multi-objective vehicle routing problem with soft time windows is investigated. The objectives that are evaluated include the minimisation of the total distance travelled, the number of vehicles and/or routes, the total waiting time and delay time of the vehicles and the makespan of a route.

Modified Pagerank Algorithm Based Real-Time Metropolitan Vehicular Traffic Routing Using GPS Crowdsourcing Data

Directory of Open Access Journals (Sweden)

Adithya Guru Vaishnav.S

2015-08-01

Full Text Available This paper aims at providing a theoretical framework to find an optimized route from any source to destination considering the real-time traffic congestion issues. The distance of various possible routes from the source and destination are calculated and a PathRank is allocated in the descending order of distance to each possible path. Each intermediate locations are considered as nodes of a graph and the edges are represented by real-time traffic flow monitored using GoogleMaps GPS crowdsourcing data. The Page Rank is calculated for each intermediate node. From the values of PageRank and PathRank the minimum sum term is used to find an optimized route with minimal trade-off between shortest path and real-time traffic.

Split delivery vehicle routing problem with time windows: a case study

Science.gov (United States)

Latiffianti, E.; Siswanto, N.; Firmandani, R. A.

2018-04-01

This paper aims to implement an extension of VRP so called split delivery vehicle routing problem (SDVRP) with time windows in a case study involving pickups and deliveries of workers from several points of origin and several destinations. Each origin represents a bus stop and the destination represents either site or office location. An integer linear programming of the SDVRP problem is presented. The solution was generated using three stages of defining the starting points, assigning busses, and solving the SDVRP with time windows using an exact method. Although the overall computational time was relatively lengthy, the results indicated that the produced solution was better than the existing routing and scheduling that the firm used. The produced solution was also capable of reducing fuel cost by 9% that was obtained from shorter total distance travelled by the shuttle buses.

Improvement In MAODV Protocol Using Location Based Routing Protocol

Directory of Open Access Journals (Sweden)

Kaur Sharnjeet

2016-01-01

Full Text Available Energy saving is difficult in wireless sensor network (WSN due to limited resources. Each node in WSN is constrained by their limited battery power for their energy. The energy is reduced as the time goes off due to the packet transmission and reception. Energy management techniques are necessary to minimize the total power consumption of all the nodes in the network in order to maximize its life span. Our proposed protocol Location based routing (LBR aimed to find a path which utilizes the minimum energy to transmit the packets between the source and the destination. The required energy for the transmission and reception of data is evaluated in MATLAB. LBR is implemented on Multicast Ad hoc On Demand Distance Vector Routing Protocol (MAODV to manage the energy consumption in the transmission and reception of data. Simulation results of LBR show the energy consumption has been reduced.

Integration of real-time mapping technology in disaster relief distribution.

Science.gov (United States)

2013-02-01

Vehicle routing for disaster relief distribution involves many challenges that distinguish this problem from those in commercial settings, given the time sensitive and resource constrained nature of relief activities. While operations research approa...

Refinements of the column generation process for the Vehicle Routing Problem with Time Windows

DEFF Research Database (Denmark)

Larsen, Jesper

2004-01-01

interval denoted the time window. The objective is to determine routes for the vehicles that minimizes the accumulated cost (or distance) with respect to the above mentioned constraints. Currently the best approaches for determining optimal solutions are based on column generation and Branch......-and-Bound, also known as Branch-and-Price. This paper presents two ideas for run-time improvements of the Branch-and-Price framework for the Vehicle Routing Problem with Time Windows. Both ideas reveal a significant potential for using run-time refinements when speeding up an exact approach without compromising...

Optimal Route Searching with Multiple Dynamical Constraints—A Geometric Algebra Approach

Directory of Open Access Journals (Sweden)

Dongshuang Li

2018-05-01

Full Text Available The process of searching for a dynamic constrained optimal path has received increasing attention in traffic planning, evacuation, and personalized or collaborative traffic service. As most existing multiple constrained optimal path (MCOP methods cannot search for a path given various types of constraints that dynamically change during the search, few approaches for dynamic multiple constrained optimal path (DMCOP with type II dynamics are available for practical use. In this study, we develop a method to solve the DMCOP problem with type II dynamics based on the unification of various types of constraints under a geometric algebra (GA framework. In our method, the network topology and three different types of constraints are represented by using algebraic base coding. With a parameterized optimization of the MCOP algorithm based on a greedy search strategy under the generation-refinement paradigm, this algorithm is found to accurately support the discovery of optimal paths as the constraints of numerical values, nodes, and route structure types are dynamically added to the network. The algorithm was tested with simulated cases of optimal tourism route searches in China’s road networks with various combinations of constraints. The case study indicates that our algorithm can not only solve the DMCOP with different types of constraints but also use constraints to speed up the route filtering.

Bicriterion a priori route choice in stochastic time-dependent networks

DEFF Research Database (Denmark)

Nielsen, Lars Relund; Andersen, Kim Allan; Pretolani, Daniele

In recent years there has been a growing interest in using stochastic time-dependent (STD) networks as a modelling tool for a number of applications within such areas as transportation and telecommunications. It is known that an optimal routing policy does not necessarily correspond to a path...

Bicriterion a priori route choice in stochastic time-dependent networks

DEFF Research Database (Denmark)

Nielsen, Lars Relund; Pretolani, D; Andersen, K A

2006-01-01

In recent years there has been a growing interest in using stochastic time-dependent (STD) networks as a modelling tool for a number of applications within such areas as transportation and telecommunications. It is known that an optimal routing policy does not necessarily correspond to a path...

Operating Time Division for a Bus Route Based on the Recovery of GPS Data

Directory of Open Access Journals (Sweden)

Jian Wang

2017-01-01

Full Text Available Bus travel time is an important source of data for time of day partition of the bus route. However, in practice, a bus driver may deliberately speed up or slow down on route so as to follow the predetermined timetable. The raw GPS data collected by the GPS device equipped on the bus, as a result, cannot reflect its real operating conditions. To address this concern, this study first develops a method to identify whether there is deliberate speed-up or slow-down movement of a bus. Building upon the relationships between the intersection delay, link travel time, and traffic flow, a recovery method is established for calculating the real bus travel time. Using the dwell time at each stop and the recovered travel time between each of them as the division indexes, a sequential clustering-based time of day partition method is proposed. The effectiveness of the developed method is demonstrated using the data of bus route 63 in Harbin, China. Results show that the partition method can help bus enterprises to design reasonable time of day intervals and significantly improve their level of service.

Sailing Vessel Routing Considering Safety Zone and Penalty Time for Altering Course

Directory of Open Access Journals (Sweden)

Marcin Zyczkowski

2017-06-01

Full Text Available In this paper we introduce new model for simulation sea vessel routing. Besides a vessel types (polar diagram and weather forecast, travel security and the number of maneuvers are considered. Based on these data both the minimal travelling costs and the minimal processing time are found for different vessels and different routes. To test our model the applications SailingAssistance wad improved. The obtained results shows that we can obtain quite acceptable results.

The waste collection vehicle routing problem with time windows in a city logistics context

DEFF Research Database (Denmark)

Buhrkal, Katja Frederik; Larsen, Allan; Røpke, Stefan

2012-01-01

Collection of waste is an important logistic activity within any city. In this paper we study how to collect waste in an efficient way. We study the Waste Collection Vehicle Routing Problem with Time Window which is concerned with finding cost optimal routes for garbage trucks such that all garbage...

The Vehicle Routing Problem with Time Windows and Temporal Dependencies

DEFF Research Database (Denmark)

Rasmussen, Matias Sevel; Dohn, Anders Høeg; Larsen, Jesper

to be scheduled with a certain slack between them. They refer to the vehicle problem as having interdependent time windows. Temporal dependencies have been modeled for a home care routing problem in a mixed integer programming model (MIP) which was solved with a standard MIP solver. An application with general...

Cross-training workers in dual resource constrained systems with heterogeneous processing times

NARCIS (Netherlands)

Bokhorst, J. A. C.; Gaalman, G. J. C.

2009-01-01

In this paper, we explore the effect of cross-training workers in Dual Resource Constrained (DRC) systems with machines having different mean processing times. By means of queuing and simulation analysis, we show that the detrimental effects of pooling (cross-training) previously found in single

Multidepot UAV Routing Problem with Weapon Configuration and Time Window

Directory of Open Access Journals (Sweden)

Tianren Zhou

2018-01-01

Full Text Available In recent wars, there is an increasing trend that unmanned aerial vehicles (UAVs are utilized to conduct military attacking missions. In this paper, we investigate a novel multidepot UAV routing problem with consideration of weapon configuration in the UAV and the attacking time window of the target. A mixed-integer linear programming model is developed to jointly optimize three kinds of decisions: the weapon configuration strategy in the UAV, the routing strategy of target, and the allocation strategy of weapons to targets. An adaptive large neighborhood search (ALNS algorithm is proposed for solving the problem, which is tested by randomly generated instances covering the small, medium, and large sizes. Experimental results confirm the effectiveness and robustness of the proposed ALNS algorithm.

Analysis of Pervasive Mobile Ad Hoc Routing Protocols

Science.gov (United States)

Qadri, Nadia N.; Liotta, Antonio

Mobile ad hoc networks (MANETs) are a fundamental element of pervasive networks and therefore, of pervasive systems that truly support pervasive computing, where user can communicate anywhere, anytime and on-the-fly. In fact, future advances in pervasive computing rely on advancements in mobile communication, which includes both infrastructure-based wireless networks and non-infrastructure-based MANETs. MANETs introduce a new communication paradigm, which does not require a fixed infrastructure - they rely on wireless terminals for routing and transport services. Due to highly dynamic topology, absence of established infrastructure for centralized administration, bandwidth constrained wireless links, and limited resources in MANETs, it is challenging to design an efficient and reliable routing protocol. This chapter reviews the key studies carried out so far on the performance of mobile ad hoc routing protocols. We discuss performance issues and metrics required for the evaluation of ad hoc routing protocols. This leads to a survey of existing work, which captures the performance of ad hoc routing algorithms and their behaviour from different perspectives and highlights avenues for future research.

The Electric Fleet Size and Mix Vehicle Routing Problem with Time Windows and Recharging Stations

DEFF Research Database (Denmark)

Hiermann, Gerhard; Puchinger, Jakob; Røpke, Stefan

2016-01-01

Due to new regulations and further technological progress in the field of electric vehicles, the research community faces the new challenge of incorporating the electric energy based restrictions into vehicle routing problems. One of these restrictions is the limited battery capacity which makes...... detours to recharging stations necessary, thus requiring efficient tour planning mechanisms in order to sustain the competitiveness of electric vehicles compared to conventional vehicles. We introduce the Electric Fleet Size and Mix Vehicle Routing Problem with Time Windows and Recharging Stations (E......-FSMFTW) to model decisions to be made with regards to fleet composition and the actual vehicle routes including the choice of recharging times and locations. The available vehicle types differ in their transport capacity, battery size and acquisition cost. Furthermore, we consider time windows at customer...

The Time-Dependent Multiple-Vehicle Prize-Collecting Arc Routing Problem

DEFF Research Database (Denmark)

Black, Daniel; Eglese, Richard; Wøhlk, Sanne

2015-01-01

-life traffic situations where the travel times change with the time of day are taken into account. Two metaheuristic algorithms, one based on Variable Neighborhood Search and one based on Tabu Search, are proposed and tested for a set of benchmark problems, generated from real road networks and travel time......In this paper, we introduce a multi vehicle version of the Time-Dependent Prize-Collecting Arc Routing Problem (TD-MPARP). It is inspired by a situation where a transport manager has to choose between a number of full truck load pick-ups and deliveries to be performed by a fleet of vehicles. Real...

Robust model predictive control for constrained continuous-time nonlinear systems

Science.gov (United States)

Sun, Tairen; Pan, Yongping; Zhang, Jun; Yu, Haoyong

2018-02-01

In this paper, a robust model predictive control (MPC) is designed for a class of constrained continuous-time nonlinear systems with bounded additive disturbances. The robust MPC consists of a nonlinear feedback control and a continuous-time model-based dual-mode MPC. The nonlinear feedback control guarantees the actual trajectory being contained in a tube centred at the nominal trajectory. The dual-mode MPC is designed to ensure asymptotic convergence of the nominal trajectory to zero. This paper extends current results on discrete-time model-based tube MPC and linear system model-based tube MPC to continuous-time nonlinear model-based tube MPC. The feasibility and robustness of the proposed robust MPC have been demonstrated by theoretical analysis and applications to a cart-damper springer system and a one-link robot manipulator.

A First-order Prediction-Correction Algorithm for Time-varying (Constrained) Optimization: Preprint

Energy Technology Data Exchange (ETDEWEB)

Dall-Anese, Emiliano [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Simonetto, Andrea [Universite catholique de Louvain

2017-07-25

This paper focuses on the design of online algorithms based on prediction-correction steps to track the optimal solution of a time-varying constrained problem. Existing prediction-correction methods have been shown to work well for unconstrained convex problems and for settings where obtaining the inverse of the Hessian of the cost function can be computationally affordable. The prediction-correction algorithm proposed in this paper addresses the limitations of existing methods by tackling constrained problems and by designing a first-order prediction step that relies on the Hessian of the cost function (and do not require the computation of its inverse). Analytical results are established to quantify the tracking error. Numerical simulations corroborate the analytical results and showcase performance and benefits of the algorithms.

A Novel Spatial-Temporal Voronoi Diagram-Based Heuristic Approach for Large-Scale Vehicle Routing Optimization with Time Constraints

Directory of Open Access Journals (Sweden)

Wei Tu

2015-10-01

Full Text Available Vehicle routing optimization (VRO designs the best routes to reduce travel cost, energy consumption, and carbon emission. Due to non-deterministic polynomial-time hard (NP-hard complexity, many VROs involved in real-world applications require too much computing effort. Shortening computing time for VRO is a great challenge for state-of-the-art spatial optimization algorithms. From a spatial-temporal perspective, this paper presents a spatial-temporal Voronoi diagram-based heuristic approach for large-scale vehicle routing problems with time windows (VRPTW. Considering time constraints, a spatial-temporal Voronoi distance is derived from the spatial-temporal Voronoi diagram to find near neighbors in the space-time searching context. A Voronoi distance decay strategy that integrates a time warp operation is proposed to accelerate local search procedures. A spatial-temporal feature-guided search is developed to improve unpromising micro route structures. Experiments on VRPTW benchmarks and real-world instances are conducted to verify performance. The results demonstrate that the proposed approach is competitive with state-of-the-art heuristics and achieves high-quality solutions for large-scale instances of VRPTWs in a short time. This novel approach will contribute to spatial decision support community by developing an effective vehicle routing optimization method for large transportation applications in both public and private sectors.

Constraining the timing of palaeosol development in Iranian arid environments using OSL dating

DEFF Research Database (Denmark)

Rashidi, Zakieh; Sohbati, Reza; Karimi, Alireza

2018-01-01

are compared to investigate the degree of bleaching of quartz OSL in individual samples at the time of deposition. A comparison between the quartz OSL and K-feldspar IR50 ages shows that 12 out of 15 samples were probably well-bleached prior to deposition. The 17 OSL ages constrain at least four broad phases......The ages of palaeosols in arid environments in Iran are constrained using the optically stimulated luminescence (OSL) signal from quartz. The luminescence properties of quartz OSL and K-feldspar infrared stimulated luminescence (IRSL) at 50 °C (IR50) and post-IR IRSL at 290 °C (pIRIR290) signals...

Late time CMB anisotropies constrain mini-charged particles

Energy Technology Data Exchange (ETDEWEB)

Burrage, C.; Redondo, J.; Ringwald, A. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Jaeckel, J. [Univ. of Durham, Inst. for Particle Physics Phenomenology (United Kingdom)

2009-09-15

Observations of the temperature anisotropies induced as light from the CMB passes through large scale structures in the late universe are a sensitive probe of the interactions of photons in such environments. In extensions of the Standard Model which give rise to mini-charged particles, photons propagating through transverse magnetic fields can be lost to pair production of such particles. Such a decrement in the photon flux would occur as photons from the CMB traverse the magnetic fields of galaxy clusters. Therefore late time CMB anisotropies can be used to constrain the properties of mini- charged particles. We outline how this test is constructed, and present new constraints on mini-charged particles from observations of the Sunyaev-Zel'dovich effect in the Coma cluster. (orig.)

Cost-Effective Encryption-Based Autonomous Routing Protocol for Efficient and Secure Wireless Sensor Networks.

Science.gov (United States)

Saleem, Kashif; Derhab, Abdelouahid; Orgun, Mehmet A; Al-Muhtadi, Jalal; Rodrigues, Joel J P C; Khalil, Mohammed Sayim; Ali Ahmed, Adel

2016-03-31

The deployment of intelligent remote surveillance systems depends on wireless sensor networks (WSNs) composed of various miniature resource-constrained wireless sensor nodes. The development of routing protocols for WSNs is a major challenge because of their severe resource constraints, ad hoc topology and dynamic nature. Among those proposed routing protocols, the biology-inspired self-organized secure autonomous routing protocol (BIOSARP) involves an artificial immune system (AIS) that requires a certain amount of time to build up knowledge of neighboring nodes. The AIS algorithm uses this knowledge to distinguish between self and non-self neighboring nodes. The knowledge-building phase is a critical period in the WSN lifespan and requires active security measures. This paper proposes an enhanced BIOSARP (E-BIOSARP) that incorporates a random key encryption mechanism in a cost-effective manner to provide active security measures in WSNs. A detailed description of E-BIOSARP is presented, followed by an extensive security and performance analysis to demonstrate its efficiency. A scenario with E-BIOSARP is implemented in network simulator 2 (ns-2) and is populated with malicious nodes for analysis. Furthermore, E-BIOSARP is compared with state-of-the-art secure routing protocols in terms of processing time, delivery ratio, energy consumption, and packet overhead. The findings show that the proposed mechanism can efficiently protect WSNs from selective forwarding, brute-force or exhaustive key search, spoofing, eavesdropping, replaying or altering of routing information, cloning, acknowledgment spoofing, HELLO flood attacks, and Sybil attacks.

Cost-Effective Encryption-Based Autonomous Routing Protocol for Efficient and Secure Wireless Sensor Networks

Science.gov (United States)

Saleem, Kashif; Derhab, Abdelouahid; Orgun, Mehmet A.; Al-Muhtadi, Jalal; Rodrigues, Joel J. P. C.; Khalil, Mohammed Sayim; Ali Ahmed, Adel

2016-01-01

The deployment of intelligent remote surveillance systems depends on wireless sensor networks (WSNs) composed of various miniature resource-constrained wireless sensor nodes. The development of routing protocols for WSNs is a major challenge because of their severe resource constraints, ad hoc topology and dynamic nature. Among those proposed routing protocols, the biology-inspired self-organized secure autonomous routing protocol (BIOSARP) involves an artificial immune system (AIS) that requires a certain amount of time to build up knowledge of neighboring nodes. The AIS algorithm uses this knowledge to distinguish between self and non-self neighboring nodes. The knowledge-building phase is a critical period in the WSN lifespan and requires active security measures. This paper proposes an enhanced BIOSARP (E-BIOSARP) that incorporates a random key encryption mechanism in a cost-effective manner to provide active security measures in WSNs. A detailed description of E-BIOSARP is presented, followed by an extensive security and performance analysis to demonstrate its efficiency. A scenario with E-BIOSARP is implemented in network simulator 2 (ns-2) and is populated with malicious nodes for analysis. Furthermore, E-BIOSARP is compared with state-of-the-art secure routing protocols in terms of processing time, delivery ratio, energy consumption, and packet overhead. The findings show that the proposed mechanism can efficiently protect WSNs from selective forwarding, brute-force or exhaustive key search, spoofing, eavesdropping, replaying or altering of routing information, cloning, acknowledgment spoofing, HELLO flood attacks, and Sybil attacks. PMID:27043572

Cost-Effective Encryption-Based Autonomous Routing Protocol for Efficient and Secure Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Kashif Saleem

2016-03-01

Full Text Available The deployment of intelligent remote surveillance systems depends on wireless sensor networks (WSNs composed of various miniature resource-constrained wireless sensor nodes. The development of routing protocols for WSNs is a major challenge because of their severe resource constraints, ad hoc topology and dynamic nature. Among those proposed routing protocols, the biology-inspired self-organized secure autonomous routing protocol (BIOSARP involves an artificial immune system (AIS that requires a certain amount of time to build up knowledge of neighboring nodes. The AIS algorithm uses this knowledge to distinguish between self and non-self neighboring nodes. The knowledge-building phase is a critical period in the WSN lifespan and requires active security measures. This paper proposes an enhanced BIOSARP (E-BIOSARP that incorporates a random key encryption mechanism in a cost-effective manner to provide active security measures in WSNs. A detailed description of E-BIOSARP is presented, followed by an extensive security and performance analysis to demonstrate its efficiency. A scenario with E-BIOSARP is implemented in network simulator 2 (ns-2 and is populated with malicious nodes for analysis. Furthermore, E-BIOSARP is compared with state-of-the-art secure routing protocols in terms of processing time, delivery ratio, energy consumption, and packet overhead. The findings show that the proposed mechanism can efficiently protect WSNs from selective forwarding, brute-force or exhaustive key search, spoofing, eavesdropping, replaying or altering of routing information, cloning, acknowledgment spoofing, HELLO flood attacks, and Sybil attacks.

A branch-and-cut algorithm for the Time Window Assignment Vehicle Routing Problem

NARCIS (Netherlands)

K. Dalmeijer (Kevin); R. Spliet (Remy)

2016-01-01

textabstractThis paper presents a branch-and-cut algorithm for the Time Window Assignment Vehicle Routing Problem (TWAVRP), the problem of assigning time windows for delivery before demand volume becomes known. A novel set of valid inequalities, the precedence inequalities, is introduced and

Power Balance AODV Routing Algorithm of WSN in Precision Agriculture Environment Monitoring

Directory of Open Access Journals (Sweden)

Xiaoqin Qin

2013-11-01

Full Text Available As one of important technologies of IOT (Internet of Things, WSN (Wireless Sensor Networks has been widely used in precision agriculture environment monitoring. WSN is a kind of energy-constrained network, but power balance is not taken into account in traditional routing protocols. A novel routing algorithm, named Power Balance Ad hoc On-Demand Distance Vector (PB-AODV, is proposed on cross-layer design. In the route discovery process of PB-AODV, routing path is established by the Received Signal Strength Indication (RSSI value. The optimal transmitting power, which is computed according to RSSI value, power threshold and node’s surplus energy, is encapsulated into Route Reply Packet. Hence, the sender node can adjust its transmission power to save energy according to the Route Reply Packet. Simulation results show that the proposed algorithm is effective for load balancing, and increases the WSN’s lifetime 14.3% consequently.

Secure Geographic Routing in Ad Hoc and Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Zahariadis Theodore

2010-01-01

Full Text Available Security in sensor networks is one of the most relevant research topics in resource constrained wireless devices and networks. Several attacks can be suffered in ad hoc and wireless sensor networks (WSN, which are highly susceptible to attacks, due to the limited resources of the nodes. In this paper, we propose innovative and lightweight localization techniques that allow for intrusion identification and isolation schemes and provide accurate location information. This information is used by our routing protocol which additionally incorporates a distributed trust model to prevent several routing attacks to the network. We finally evaluate our algorithms for accurate localization and for secure routing which have been implemented and tested in real ad hoc and wireless sensor networks.

Evacuation route planning during nuclear emergency using genetic algorithm

International Nuclear Information System (INIS)

Suman, Vitisha; Sarkar, P.K.

2012-01-01

In nuclear industry the routing in case of any emergency is a cause of concern and of great importance. Even the smallest of time saved in the affected region saves a huge amount of otherwise received dose. Genetic algorithm an optimization technique has great ability to search for the optimal path from the affected region to a destination station in a spatially addressed problem. Usually heuristic algorithms are used to carry out these types of search strategy, but due to the lack of global sampling in the feasible solution space, these algorithms have considerable possibility of being trapped into local optima. Routing problems mainly are search problems for finding the shortest distance within a time limit to cover the required number of stations taking care of the traffics, road quality, population size etc. Lack of any formal mechanisms to help decision-makers explore the solution space of their problem and thereby challenges their assumptions about the number and range of options available. The Genetic Algorithm provides a way to optimize a multi-parameter constrained problem with an ease. Here use of Genetic Algorithm to generate a range of options available and to search a solution space and selectively focus on promising combinations of criteria makes them ideally suited to such complex spatial decision problems. The emergency response and routing can be made efficient, in accessing the closest facilities and determining the shortest route using genetic algorithm. The accuracy and care in creating database can be used to improve the result of the final output. The Genetic algorithm can be used to improve the accuracy of result on the basis of distance where other algorithm cannot be obtained. The search space can be utilized to its great extend

Minimizing the Carbon Footprint for the Time-Dependent Heterogeneous-Fleet Vehicle Routing Problem with Alternative Paths

Directory of Open Access Journals (Sweden)

Wan-Yu Liu

2014-07-01

Full Text Available Torespondto the reduction of greenhouse gas emissions and global warming, this paper investigates the minimal-carbon-footprint time-dependent heterogeneous-fleet vehicle routing problem with alternative paths (MTHVRPP. This finds a route with the smallestcarbon footprint, instead of the shortestroute distance, which is the conventional approach, to serve a number of customers with a heterogeneous fleet of vehicles in cases wherethere may not be only one path between each pair of customers, and the vehicle speed differs at different times of the day. Inheriting from the NP-hardness of the vehicle routing problem, the MTHVRPP is also NP-hard. This paper further proposes a genetic algorithm (GA to solve this problem. The solution representedbyour GA determines the customer serving ordering of each vehicle type. Then, the capacity check is used to classify multiple routes of each vehicle type, and the path selection determines the detailed paths of each route. Additionally, this paper improves the energy consumption model used for calculating the carbon footprint amount more precisely. Compared with the results without alternative paths, our experimental results show that the alternative path in this experimenthas a significant impact on the experimental results in terms of carbon footprint.

Routing Service Quality—Local Driver Behavior Versus Routing Services

DEFF Research Database (Denmark)

Ceikute, Vaida; Jensen, Christian S.

2013-01-01

of the quality of one kind of location-based service, namely routing services. Specifically, the paper presents a framework that enables the comparison of the routes provided by routing services with the actual driving behaviors of local drivers. Comparisons include route length, travel time, and also route...... popularity, which are enabled by common driving behaviors found in available trajectory data. The ability to evaluate the quality of routing services enables service providers to improve the quality of their services and enables users to identify the services that best serve their needs. The paper covers......Mobile location-based services is a very successful class of services that are being used frequently by users with GPS-enabled mobile devices such as smartphones. This paper presents a study of how to exploit GPS trajectory data, which is available in increasing volumes, for the assessment...

LBMR: Load-Balanced Multipath Routing for Wireless Data-Intensive Transmission in Real-Time Medical Monitoring.

Science.gov (United States)

Tseng, Chinyang Henry

2016-05-31

In wireless networks, low-power Zigbee is an excellent network solution for wireless medical monitoring systems. Medical monitoring generally involves transmission of a large amount of data and easily causes bottleneck problems. Although Zigbee's AODV mesh routing provides extensible multi-hop data transmission to extend network coverage, it originally does not, and needs to support some form of load balancing mechanism to avoid bottlenecks. To guarantee a more reliable multi-hop data transmission for life-critical medical applications, we have developed a multipath solution, called Load-Balanced Multipath Routing (LBMR) to replace Zigbee's routing mechanism. LBMR consists of three main parts: Layer Routing Construction (LRC), a Load Estimation Algorithm (LEA), and a Route Maintenance (RM) mechanism. LRC assigns nodes into different layers based on the node's distance to the medical data gateway. Nodes can have multiple next-hops delivering medical data toward the gateway. All neighboring layer-nodes exchange flow information containing current load, which is the used by the LEA to estimate future load of next-hops to the gateway. With LBMR, nodes can choose the neighbors with the least load as the next-hops and thus can achieve load balancing and avoid bottlenecks. Furthermore, RM can detect route failures in real-time and perform route redirection to ensure routing robustness. Since LRC and LEA prevent bottlenecks while RM ensures routing fault tolerance, LBMR provides a highly reliable routing service for medical monitoring. To evaluate these accomplishments, we compare LBMR with Zigbee's AODV and another multipath protocol, AOMDV. The simulation results demonstrate LBMR achieves better load balancing, less unreachable nodes, and better packet delivery ratio than either AODV or AOMDV.

Vehicle routing with dynamic travel times : a queueing approach

NARCIS (Netherlands)

Woensel, van T.; Kerbache, L.; Peremans, H.; Vandaele, N.J.

2008-01-01

Transportation is an important component of supply chain competitiveness since it plays a major role in the inbound, inter-facility, and outbound logistics. In this context, assigning and scheduling vehicle routes is a crucial management problem. In this paper, a vehicle routing problem with dynamic

A hybrid metaheuristic for the time-dependent vehicle routing problem with hard time windows

Directory of Open Access Journals (Sweden)

N. Rincon-Garcia

2017-01-01

Full Text Available This article paper presents a hybrid metaheuristic algorithm to solve the time-dependent vehicle routing problem with hard time windows. Time-dependent travel times are influenced by different congestion levels experienced throughout the day. Vehicle scheduling without consideration of congestion might lead to underestimation of travel times and consequently missed deliveries. The algorithm presented in this paper makes use of Large Neighbourhood Search approaches and Variable Neighbourhood Search techniques to guide the search. A first stage is specifically designed to reduce the number of vehicles required in a search space by the reduction of penalties generated by time-window violations with Large Neighbourhood Search procedures. A second stage minimises the travel distance and travel time in an ‘always feasible’ search space. Comparison of results with available test instances shows that the proposed algorithm is capable of obtaining a reduction in the number of vehicles (4.15%, travel distance (10.88% and travel time (12.00% compared to previous implementations in reasonable time.

Approximation algorithms for deadline-TSP and vehicle routing with time-windows

NARCIS (Netherlands)

Bansal, N.; Blum, A.; Chawla, S.; Meyerson, A.; Babai, L.

2004-01-01

Given a metric space G on n nodes, with a start node r and deadlines D(v) for each vertex v, we consider the Deadline-TSP problem of finding a path starting at r that visits as many nodes as possible by their deadlines. We also consider the more general Vehicle Routing with Time-Windows problem, in

Constraining designs for synthesis and timing analysis a practical guide to synopsys design constraints (SDC)

CERN Document Server

Gangadharan, Sridhar

2013-01-01

This book serves as a hands-on guide to timing constraints in integrated circuit design.  Readers will learn to maximize performance of their IC designs, by specifying timing requirements correctly.  Coverage includes key aspects of the design flow impacted by timing constraints, including synthesis, static timing analysis and placement and routing.  Concepts needed for specifying timing requirements are explained in detail and then applied to specific stages in the design flow, all within the context of Synopsys Design Constraints (SDC), the industry-leading format for specifying constraints.  ·         Provides a hands-on guide to synthesis and timing analysis, using Synopsys Design Constraints (SDC), the industry-leading format for specifying constraints; ·         Includes key topics of interest to a synthesis, static timing analysis or  place and route engineer; ·         Explains which constraints command to use for ease of maintenance and reuse, given several options pos...

Multi-UAV Routing for Area Coverage and Remote Sensing with Minimum Time.

Science.gov (United States)

Avellar, Gustavo S C; Pereira, Guilherme A S; Pimenta, Luciano C A; Iscold, Paulo

2015-11-02

This paper presents a solution for the problem of minimum time coverage of ground areas using a group of unmanned air vehicles (UAVs) equipped with image sensors. The solution is divided into two parts: (i) the task modeling as a graph whose vertices are geographic coordinates determined in such a way that a single UAV would cover the area in minimum time; and (ii) the solution of a mixed integer linear programming problem, formulated according to the graph variables defined in the first part, to route the team of UAVs over the area. The main contribution of the proposed methodology, when compared with the traditional vehicle routing problem's (VRP) solutions, is the fact that our method solves some practical problems only encountered during the execution of the task with actual UAVs. In this line, one of the main contributions of the paper is that the number of UAVs used to cover the area is automatically selected by solving the optimization problem. The number of UAVs is influenced by the vehicles' maximum flight time and by the setup time, which is the time needed to prepare and launch a UAV. To illustrate the methodology, the paper presents experimental results obtained with two hand-launched, fixed-wing UAVs.

Multiple Charging Station Location-Routing Problem with Time Window of Electric Vehicle

Directory of Open Access Journals (Sweden)

Wang Li-ying

2015-11-01

Full Text Available This paper presents the electric vehicle (EV multiple charging station location-routing problem with time window to optimize the routing plan of capacitated EVs and the strategy of charging stations. In particular, the strategy of charging stations includes both infrastructure-type selection and station location decisions. The problem accounts for two critical constraints in logistic practice: the vehicle loading capacity and the customer time windows. A hybrid heuristic that incorporates an adaptive variable neighborhood search (AVNS with the tabu search algorithm for intensification was developed to address the problem. The specialized neighborhood structures and the selection methods of charging station used in the shaking step of AVNS were proposed. In contrast to the commercial solver CPLEX, experimental results on small-scale test instances demonstrate that the algorithm can find nearly optimal solutions on small-scale instances. The results on large-scale instances also show the effectiveness of the algorithm.

Enhanced DSR Routing Protocol for the Short Time Disconnected MANET

Directory of Open Access Journals (Sweden)

PAPAJ Ján

2013-05-01

Full Text Available Data delivery in Mobile Ad-Hoc network (MANET is a very difficult task due to the fact the sporadic connections between mobile nodes. For this reason, we introduce the new modified routing protocol that enables the data delivery in the case that the connections are disconnected. A key aspect of the protocol is a process of finding connections between source and destination nodes that can provide low end-to-end delay and better delivery performance in a disconnected MANET. The protocol provides the concepts of opportunistic routing of the routing packets in disconnected MANETs. In this paper we present a modification of the DSR routing protocol and also some results of a simulation.

A hybrid meta-heuristic algorithm for the vehicle routing problem with stochastic travel times considering the driver's satisfaction

Science.gov (United States)

Tavakkoli-Moghaddam, Reza; Alinaghian, Mehdi; Salamat-Bakhsh, Alireza; Norouzi, Narges

2012-05-01

A vehicle routing problem is a significant problem that has attracted great attention from researchers in recent years. The main objectives of the vehicle routing problem are to minimize the traveled distance, total traveling time, number of vehicles and cost function of transportation. Reducing these variables leads to decreasing the total cost and increasing the driver's satisfaction level. On the other hand, this satisfaction, which will decrease by increasing the service time, is considered as an important logistic problem for a company. The stochastic time dominated by a probability variable leads to variation of the service time, while it is ignored in classical routing problems. This paper investigates the problem of the increasing service time by using the stochastic time for each tour such that the total traveling time of the vehicles is limited to a specific limit based on a defined probability. Since exact solutions of the vehicle routing problem that belong to the category of NP-hard problems are not practical in a large scale, a hybrid algorithm based on simulated annealing with genetic operators was proposed to obtain an efficient solution with reasonable computational cost and time. Finally, for some small cases, the related results of the proposed algorithm were compared with results obtained by the Lingo 8 software. The obtained results indicate the efficiency of the proposed hybrid simulated annealing algorithm.

En route position and time control of aircraft using Kalman filtering of radio aid data

Science.gov (United States)

Mcgee, L. A.; Christensen, J. V.

1973-01-01

Fixed-time-of-arrival (FTA) guidance and navigation is investigated as a possible technique capable of operation within much more stringent en route separation standards and offering significant advantages in safety, higher traffic densities, and improved scheduling reliability, both en route and in the terminal areas. This study investigated the application of FTA guidance previously used in spacecraft guidance. These FTA guidance techniques have been modified and are employed to compute the velocity corrections necessary to return an aircraft to a specified great-circle reference path in order to exercise en route time and position control throughout the entire flight. The necessary position and velocity estimates to accomplish this task are provided by Kalman filtering of data from Loran-C, VORTAC/TACAN, Doppler radar, radio or barometric altitude,and altitude rate. The guidance and navigation system was evaluated using a digital simulation of the cruise phase of supersonic and subsonic flights between San Francisco and New York City, and between New York City and London.

A Secure Routing Protocol for Wireless Sensor Networks Considering Secure Data Aggregation

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Triana Mugia Rahayu

2015-06-01

Full Text Available The commonly unattended and hostile deployments of WSNs and their resource-constrained sensor devices have led to an increasing demand for secure energy-efficient protocols. Routing and data aggregation receive the most attention since they are among the daily network routines. With the awareness of such demand, we found that so far there has been no work that lays out a secure routing protocol as the foundation for a secure data aggregation protocol. We argue that the secure routing role would be rendered useless if the data aggregation scheme built on it is not secure. Conversely, the secure data aggregation protocol needs a secure underlying routing protocol as its foundation in order to be effectively optimal. As an attempt for the solution, we devise an energy-aware protocol based on LEACH and ESPDA that combines secure routing protocol and secure data aggregation protocol. We then evaluate its security effectiveness and its energy-efficiency aspects, knowing that there are always trade-off between both.

Formulations and exact algorithms for the vehicle routing problem with time windows

DEFF Research Database (Denmark)

Kallehauge, Brian

2008-01-01

In this paper we review the exact algorithms proposed in the last three decades for the solution of the vehicle routing problem with time windows (VRPTW). The exact algorithms for the VRPTW are in many aspects inherited from work on the traveling salesman problem (TSP). In recognition of this fact...

Route Choice in Subway Station during Morning Peak Hours: A Case of Guangzhou Subway

Directory of Open Access Journals (Sweden)

Jie Xu

2015-01-01

Full Text Available This paper is aimed at crowding phenomenon in the subway. As passengers are inclined to choose the route with minimum disutility, we put forward a route choice model which is constructed to achieve minimum objective function of feasibility for the optimal solution. Meanwhile we set passenger volume threshold values according to capacity of facilities. In the case of actual capacity exceeding the threshold, the decision node of constrained route will be selected; computing procedure about searching decision points will be presented. Then we should set rational restrictions at the decision node of the minimum utility function route to prevent too many passengers’ access to platform. Through certification, this series of methods can effectively ensure the safety of the station efficient operation.

New heuristics for the fleet size and mix vehicle routing problem with time windows

NARCIS (Netherlands)

Dullaert, W.; Janssens, Gerrit K.; Sirensen, K.; Vernimmen, Bert

2002-01-01

In the Fleet Size and Mix Vehicle Routing Problem with Time Windows (FSMVRPTW) customers need to be serviced in their time windows at minimal costs by a heterogeneous fleet. In this paper new heuristics for the FSMVRPTW are developed. The performance of the heuristics is shown to be significantly

A real-time Java tool chain for resource constrained platforms

DEFF Research Database (Denmark)

Korsholm, Stephan Erbs; Søndergaard, Hans; Ravn, Anders P.

2013-01-01

The Java programming language was originally developed for embedded systems, but the resource requirements of previous and current Java implementations - especially memory consumption - tend to exclude them from being used on a significant class of resource constrained embedded platforms. The con......The Java programming language was originally developed for embedded systems, but the resource requirements of previous and current Java implementations - especially memory consumption - tend to exclude them from being used on a significant class of resource constrained embedded platforms...... by integrating: (1) a lean virtual machine (HVM) without any external dependencies on POSIX-like libraries or other OS functionalities, (2) a hardware abstraction layer, implemented almost entirely in Java through the use of hardware objects, first level interrupt handlers, and native variables, and (3....... An evaluation of the presented solution shows that the miniCDj benchmark gets reduced to a size where it can run on resource constrained platforms....

Energy-Efficient Cluster Based Routing Protocol in Mobile Ad Hoc Networks Using Network Coding

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Srinivas Kanakala

2014-01-01

Full Text Available In mobile ad hoc networks, all nodes are energy constrained. In such situations, it is important to reduce energy consumption. In this paper, we consider the issues of energy efficient communication in MANETs using network coding. Network coding is an effective method to improve the performance of wireless networks. COPE protocol implements network coding concept to reduce number of transmissions by mixing the packets at intermediate nodes. We incorporate COPE into cluster based routing protocol to further reduce the energy consumption. The proposed energy-efficient coding-aware cluster based routing protocol (ECCRP scheme applies network coding at cluster heads to reduce number of transmissions. We also modify the queue management procedure of COPE protocol to further improve coding opportunities. We also use an energy efficient scheme while selecting the cluster head. It helps to increase the life time of the network. We evaluate the performance of proposed energy efficient cluster based protocol using simulation. Simulation results show that the proposed ECCRP algorithm reduces energy consumption and increases life time of the network.

Multipath Routing in Wireless Sensor Networks: Survey and Research Challenges

Science.gov (United States)

Radi, Marjan; Dezfouli, Behnam; Bakar, Kamalrulnizam Abu; Lee, Malrey

2012-01-01

A wireless sensor network is a large collection of sensor nodes with limited power supply and constrained computational capability. Due to the restricted communication range and high density of sensor nodes, packet forwarding in sensor networks is usually performed through multi-hop data transmission. Therefore, routing in wireless sensor networks has been considered an important field of research over the past decade. Nowadays, multipath routing approach is widely used in wireless sensor networks to improve network performance through efficient utilization of available network resources. Accordingly, the main aim of this survey is to present the concept of the multipath routing approach and its fundamental challenges, as well as the basic motivations for utilizing this technique in wireless sensor networks. In addition, we present a comprehensive taxonomy on the existing multipath routing protocols, which are especially designed for wireless sensor networks. We highlight the primary motivation behind the development of each protocol category and explain the operation of different protocols in detail, with emphasis on their advantages and disadvantages. Furthermore, this paper compares and summarizes the state-of-the-art multipath routing techniques from the network application point of view. Finally, we identify open issues for further research in the development of multipath routing protocols for wireless sensor networks. PMID:22368490

Multipath routing in wireless sensor networks: survey and research challenges.

Science.gov (United States)

Radi, Marjan; Dezfouli, Behnam; Abu Bakar, Kamalrulnizam; Lee, Malrey

2012-01-01

A wireless sensor network is a large collection of sensor nodes with limited power supply and constrained computational capability. Due to the restricted communication range and high density of sensor nodes, packet forwarding in sensor networks is usually performed through multi-hop data transmission. Therefore, routing in wireless sensor networks has been considered an important field of research over the past decade. Nowadays, multipath routing approach is widely used in wireless sensor networks to improve network performance through efficient utilization of available network resources. Accordingly, the main aim of this survey is to present the concept of the multipath routing approach and its fundamental challenges, as well as the basic motivations for utilizing this technique in wireless sensor networks. In addition, we present a comprehensive taxonomy on the existing multipath routing protocols, which are especially designed for wireless sensor networks. We highlight the primary motivation behind the development of each protocol category and explain the operation of different protocols in detail, with emphasis on their advantages and disadvantages. Furthermore, this paper compares and summarizes the state-of-the-art multipath routing techniques from the network application point of view. Finally, we identify open issues for further research in the development of multipath routing protocols for wireless sensor networks.

Routing and scheduling problems

DEFF Research Database (Denmark)

Reinhardt, Line Blander

couple of decades. To deliver competitive service and price, transportation today needs to be cost effective. A company requiring for things to be shipped will aim at having the freight shipped as cheaply as possible while often satisfying certain time constraints. For the transportation company......, the effectiveness of the network is of importance aiming at satisfying as many costumer demands as possible at a low cost. Routing represent a path between locations such as an origin and destination for the object routed. Sometimes routing has a time dimension as well as the physical paths. This may...... set cost making the cost of the individual vehicle routes inter-dependant. Depending on the problem type, the size of the problems and time available for solving, different solution methods can be applicable. In this thesis both heuristic methods and several exact methods are investigated depending...

The Prohibitive Link between Position-based Routing and Planarity

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David Cairns

2013-12-01

Full Text Available Position-based routing is touted as an ideal routing strategy for resource-constrained wireless networks. One persistent barrier to adoption is due to its recovery phase, where messages are forwarded according to leftor right-hand rule (LHR. This is often referred to as face-routing. In this paper we investigate the limits of LHR with respect to planarity.We show that the gap between non-planarity and successful delivery is a single link within a single configuration. Our work begins with an analysis to enumerate all node configurations that cause intersections in the unit-disc graph. We find that left-hand rule is able to recover from all but a single case, the ‘umbrella’ configuration so named for its appearance. We use this information to propose the Prohibitive Link Detection Protocol (PLDP that can guarantee delivery over non-planar graphs using standard face-routing techniques. As the name implies, the protocol detects and circumvents the ‘bad’ links that hamper LHR. The goal of this work is to maintain routing guarantees while disturbing the network graph as little as possible. In doing so, a new starting point emerges from which to build rich distributed protocols in the spirit of CLDP and GDSTR.

A real-time Java tool chain for resource constrained platforms

DEFF Research Database (Denmark)

Korsholm, Stephan E.; Søndergaard, Hans; Ravn, Anders Peter

2014-01-01

The Java programming language was originally developed for embedded systems, but the resource requirements of previous and current Java implementations – especially memory consumption – tend to exclude them from being used on a significant class of resource constrained embedded platforms. The con......The Java programming language was originally developed for embedded systems, but the resource requirements of previous and current Java implementations – especially memory consumption – tend to exclude them from being used on a significant class of resource constrained embedded platforms...... by integrating the following: (1) a lean virtual machine without any external dependencies on POSIX-like libraries or other OS functionalities; (2) a hardware abstraction layer, implemented almost entirely in Java through the use of hardware objects, first level interrupt handlers, and native variables; and (3....... An evaluation of the presented solution shows that the miniCDj benchmark gets reduced to a size where it can run on resource constrained platforms....

Perception bias in route choice

NARCIS (Netherlands)

Vreeswijk, Jacob Dirk; Thomas, Tom; van Berkum, Eric C.; van Arem, Bart

2014-01-01

Travel time is probably one of the most studied attributes in route choice. Recently, perception of travel time received more attention as several studies have shown its importance in explaining route choice behavior. In particular, travel time estimates by travelers appear to be biased against

Indoor 3D Route Modeling Based On Estate Spatial Data

Science.gov (United States)

Zhang, H.; Wen, Y.; Jiang, J.; Huang, W.

2014-04-01

Indoor three-dimensional route model is essential for space intelligence navigation and emergency evacuation. This paper is motivated by the need of constructing indoor route model automatically and as far as possible. By comparing existing building data sources, this paper firstly explained the reason why the estate spatial management data is chosen as the data source. Then, an applicable method of construction three-dimensional route model in a building is introduced by establishing the mapping relationship between geographic entities and their topological expression. This data model is a weighted graph consist of "node" and "path" to express the spatial relationship and topological structure of a building components. The whole process of modelling internal space of a building is addressed by two key steps: (1) each single floor route model is constructed, including path extraction of corridor using Delaunay triangulation algorithm with constrained edge, fusion of room nodes into the path; (2) the single floor route model is connected with stairs and elevators and the multi-floor route model is eventually generated. In order to validate the method in this paper, a shopping mall called "Longjiang New City Plaza" in Nanjing is chosen as a case of study. And the whole building space is constructed according to the modelling method above. By integrating of existing path finding algorithm, the usability of this modelling method is verified, which shows the indoor three-dimensional route modelling method based on estate spatial data in this paper can support indoor route planning and evacuation route design very well.

A constructive heuristic for time-dependent multi-depot vehicle routing problem with time-windows and heterogeneous fleet

Directory of Open Access Journals (Sweden)

Behrouz Afshar-Nadjafi

2017-01-01

Full Text Available In this paper, we consider the time-dependent multi-depot vehicle routing problem. The objective is to minimize the total heterogeneous fleet cost assuming that the travel time between locations depends on the departure time. Also, hard time window constraints for the customers and limitation on maximum number of the vehicles in depots must be satisfied. The problem is formulated as a mixed integer programming model. A constructive heuristic procedure is proposed for the problem. Also, the efficiency of the proposed algorithm is evaluated on 180 test problems. The obtained computational results indicate that the procedure is capable to obtain a satisfying solution.

The multi-depot electric vehicle location routing problem with time windows

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Juan Camilo Paz

2018-01-01

Full Text Available In this paper, the Multi-Depot Electric Vehicle Location Routing Problem with Time Windows (MDVLRP is addressed. This problem is an extension of the MDVLRP, where electric vehicles are used instead of internal combustion engine vehicles. The recent development of this model is explained by the advantages of this technology, such as the diminution of carbon dioxide emissions, and the support that they can provide to the design of the logistic and energy-support structure of electric vehicle fleets. There are many models that extend the classical VRP model to take electric vehicles into consideration, but the multi-depot case for location-routing models has not been worked out yet. Moreover, we consider the availability of two energy supply technologies: the “Plug-in” Conventional Charge technology, and Battery Swapping Stations; options in which the recharging time is a function of the amount of energy to charge and a fixed time, respectively. Three models are proposed: one for each of the technologies mentioned above, and another in which both options are taken in consideration. The models were solved for small scale instances using C++ and Cplex 12.5. The results show that the models can be used to design logistic and energy-support structures, and compare the performance of the different options of energy supply, as well as measure the impact of these decisions on the overall distance traveled or other optimization objectives that could be worked on in the future.

Distance Constrained Based Adaptive Flocking Control for Multiagent Networks with Time Delay

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Qing Zhang

2015-01-01

Full Text Available The flocking control of multiagent system is a new type of decentralized control method, which has aroused great attention. The paper includes a detailed research in terms of distance constrained based adaptive flocking control for multiagent system with time delay. Firstly, the program on the adaptive flocking with time delay of multiagent is proposed. Secondly, a kind of adaptive controllers and updating laws are presented. According to the Lyapunov stability theory, it is proved that the distance between agents can be larger than a constant during the motion evolution. What is more, velocities of each agent come to the same asymptotically. Finally, the analytical results can be verified by a numerical example.

On the optimal identification of tag sets in time-constrained RFID configurations.

Science.gov (United States)

Vales-Alonso, Javier; Bueno-Delgado, María Victoria; Egea-López, Esteban; Alcaraz, Juan José; Pérez-Mañogil, Juan Manuel

2011-01-01

In Radio Frequency Identification facilities the identification delay of a set of tags is mainly caused by the random access nature of the reading protocol, yielding a random identification time of the set of tags. In this paper, the cumulative distribution function of the identification time is evaluated using a discrete time Markov chain for single-set time-constrained passive RFID systems, namely those ones where a single group of tags is assumed to be in the reading area and only for a bounded time (sojourn time) before leaving. In these scenarios some tags in a set may leave the reader coverage area unidentified. The probability of this event is obtained from the cumulative distribution function of the identification time as a function of the sojourn time. This result provides a suitable criterion to minimize the probability of losing tags. Besides, an identification strategy based on splitting the set of tags in smaller subsets is also considered. Results demonstrate that there are optimal splitting configurations that reduce the overall identification time while keeping the same probability of losing tags.

Intelligent routing protocol for ad hoc wireless network

Science.gov (United States)

Peng, Chaorong; Chen, Chang Wen

2006-05-01

A novel routing scheme for mobile ad hoc networks (MANETs), which combines hybrid and multi-inter-routing path properties with a distributed topology discovery route mechanism using control agents is proposed in this paper. In recent years, a variety of hybrid routing protocols for Mobile Ad hoc wireless networks (MANETs) have been developed. Which is proactively maintains routing information for a local neighborhood, while reactively acquiring routes to destinations beyond the global. The hybrid protocol reduces routing discovery latency and the end-to-end delay by providing high connectivity without requiring much of the scarce network capacity. On the other side the hybrid routing protocols in MANETs likes Zone Routing Protocol still need route "re-discover" time when a route between zones link break. Sine the topology update information needs to be broadcast routing request on local zone. Due to this delay, the routing protocol may not be applicable for real-time data and multimedia communication. We utilize the advantages of a clustering organization and multi-routing path in routing protocol to achieve several goals at the same time. Firstly, IRP efficiently saves network bandwidth and reduces route reconstruction time when a routing path fails. The IRP protocol does not require global periodic routing advertisements, local control agents will automatically monitor and repair broke links. Secondly, it efficiently reduces congestion and traffic "bottlenecks" for ClusterHeads in clustering network. Thirdly, it reduces significant overheads associated with maintaining clusters. Fourthly, it improves clusters stability due to dynamic topology changing frequently. In this paper, we present the Intelligent Routing Protocol. First, we discuss the problem of routing in ad hoc networks and the motivation of IRP. We describe the hierarchical architecture of IRP. We describe the routing process and illustrate it with an example. Further, we describe the control manage

Constraint Programming based Local Search for the Vehicle Routing Problem with Time Windows

OpenAIRE

Sala Reixach, Joan

2012-01-01

El projecte es centra en el "Vehicle Routing Problem with Time Windows". Explora i testeja un mètode basat en una formulació del problema en termes de programació de restriccions. Implementa un mètode de cerca local amb la capacitat de fer grans moviments anomenat "Large Neighbourhood Search".

Method and System for Dynamic Automated Corrections to Weather Avoidance Routes for Aircraft in En Route Airspace

Science.gov (United States)

McNally, B. David (Inventor); Erzberger, Heinz (Inventor); Sheth, Kapil (Inventor)

2015-01-01

A dynamic weather route system automatically analyzes routes for in-flight aircraft flying in convective weather regions and attempts to find more time and fuel efficient reroutes around current and predicted weather cells. The dynamic weather route system continuously analyzes all flights and provides reroute advisories that are dynamically updated in real time while the aircraft are in flight. The dynamic weather route system includes a graphical user interface that allows users to visualize, evaluate, modify if necessary, and implement proposed reroutes.

Layered and Laterally Constrained 2D Inversion of Time Domain Induced Polarization Data

DEFF Research Database (Denmark)

Fiandaca, Gianluca; Ramm, James; Auken, Esben

description of the transmitter waveform and of the receiver transfer function allowing for a quantitative interpretation of the parameters. The code has been optimized for parallel computation and the inversion time is comparable to codes inverting just for direct current resistivity. The new inversion......In a sedimentary environment, quasi-layered models often represent the actual geology more accurately than smooth minimum-structure models. We have developed a new layered and laterally constrained inversion algorithm for time domain induced polarization data. The algorithm is based on the time...... transform of a complex resistivity forward response and the inversion extracts the spectral information of the time domain measures in terms of the Cole-Cole parameters. The developed forward code and inversion algorithm use the full time decay of the induced polarization response, together with an accurate...

Real time monitoring system used in route planning for the electric vehicle

Science.gov (United States)

Ionescu, LM; Mazare, A.; Serban, G.; Ionita, S.

2017-10-01

The electric vehicle is a new consumer of electricity that is becoming more and more widespread. Under these circumstances, new strategies for optimizing power consumption and increasing vehicle autonomy must be designed. These must include route planning along with consumption, fuelling points and points of interest. The hardware and software solution proposed by us allows: non-invasive monitoring of power consumption, energy autonomy - it does not add any extra consumption, data transmission to a server and data fusion with the route, the points of interest of the route and the power supply points. As a result: an optimal route planning service will be provided to the driver, considering the route, the requirements of the electric vehicle and the consumer profile. The solution can be easily installed on any type of electric car - it does not involve any intervention on the equipment.

Simultaneous Optimization of Container Ship Sailing Speed and Container Routing with Transit Time Restrictions

DEFF Research Database (Denmark)

Karsten, Christian Vad; Røpke, Stefan; Pisinger, David

We introduce a decision support tool for liner shipping companies to optimally determine the sailing speed and needed fleet for a global network. As a novelty we incorporate cargo routing decisions with tight transit time restrictions on each container such that we get a realistic picture...

Performansi Algoritma CODEQ dalam Penyelesaian Vehicle Routing Problem

Directory of Open Access Journals (Sweden)

Annisa Kesy Garside

2014-01-01

Full Text Available Genetic Algorithm, Tabu Search, Simulated Annealing, and Ant Colony Optimization showed a good performance in solving vehicle routing problem. However, the generated solution of those algorithms was changeable regarding on the input parameter of each algorithm. CODEQ is a new, parameter free meta-heuristic algorithm that had been successfully used to solve constrained optimization problems, integer programming, and feed-forward neural network. The purpose of this research are improving CODEQ algorithm to solve vehicle routing problem and testing the performance of the improved algorithm. CODEQ algorithm is started with population initiation as initial solution, generated of mutant vector for each parent in every iteration, replacement of parent by mutant when fitness function value of mutant is better than parent’s, generated of new vector for each iteration based on opposition value or chaos principle, replacement of worst solution by new vector when fitness function value of new vector is better, iteration ceasing when stooping criterion is achieved, and sub-tour determination based on vehicle capacity constraint. The result showed that the average deviation of the best-known and the best-test value is 6.35%. Therefore, CODEQ algorithm is good in solving vehicle routing problem.

A granular tabu search algorithm for a real case study of a vehicle routing problem with a heterogeneous fleet and time windows

Directory of Open Access Journals (Sweden)

Jose Bernal

2017-10-01

Full Text Available Purpose: We consider a real case study of a vehicle routing problem with a heterogeneous fleet and time windows (HFVRPTW for a franchise company bottling Coca-Cola products in Colombia. This study aims to determine the routes to be performed to fulfill the demand of the customers by using a heterogeneous fleet and considering soft time windows. The objective is to minimize the distance traveled by the performed routes. Design/methodology/approach: We propose a two-phase heuristic algorithm. In the proposed approach, after an initial phase (first phase, a granular tabu search is applied during the improvement phase (second phase. Two additional procedures are considered to help that the algorithm could escape from local optimum, given that during a given number of iterations there has been no improvement. Findings: Computational experiments on real instances show that the proposed algorithm is able to obtain high-quality solutions within a short computing time compared to the results found by the software that the company currently uses to plan the daily routes. Originality/value: We propose a novel metaheuristic algorithm for solving a real routing problem by considering heterogeneous fleet and time windows. The efficiency of the proposed approach has been tested on real instances, and the computational experiments shown its applicability and performance for solving NP-Hard Problems related with routing problems with similar characteristics. The proposed algorithm was able to improve some of the current solutions applied by the company by reducing the route length and the number of vehicles.

Port Authority of Allegheny County Transit Routes

Data.gov (United States)

Allegheny County / City of Pittsburgh / Western PA Regional Data Center — Shapefile of Transit Routes - Please refer to each resource for active dates of the route information. Routes change over time,

Adaptive Constrained Optimal Control Design for Data-Based Nonlinear Discrete-Time Systems With Critic-Only Structure.

Science.gov (United States)

Luo, Biao; Liu, Derong; Wu, Huai-Ning

2018-06-01

Reinforcement learning has proved to be a powerful tool to solve optimal control problems over the past few years. However, the data-based constrained optimal control problem of nonaffine nonlinear discrete-time systems has rarely been studied yet. To solve this problem, an adaptive optimal control approach is developed by using the value iteration-based Q-learning (VIQL) with the critic-only structure. Most of the existing constrained control methods require the use of a certain performance index and only suit for linear or affine nonlinear systems, which is unreasonable in practice. To overcome this problem, the system transformation is first introduced with the general performance index. Then, the constrained optimal control problem is converted to an unconstrained optimal control problem. By introducing the action-state value function, i.e., Q-function, the VIQL algorithm is proposed to learn the optimal Q-function of the data-based unconstrained optimal control problem. The convergence results of the VIQL algorithm are established with an easy-to-realize initial condition . To implement the VIQL algorithm, the critic-only structure is developed, where only one neural network is required to approximate the Q-function. The converged Q-function obtained from the critic-only VIQL method is employed to design the adaptive constrained optimal controller based on the gradient descent scheme. Finally, the effectiveness of the developed adaptive control method is tested on three examples with computer simulation.

A capacitated vehicle routing problem with order available time in e-commerce industry

Science.gov (United States)

Liu, Ling; Li, Kunpeng; Liu, Zhixue

2017-03-01

In this article, a variant of the well-known capacitated vehicle routing problem (CVRP) called the capacitated vehicle routing problem with order available time (CVRPOAT) is considered, which is observed in the operations of the current e-commerce industry. In this problem, the orders are not available for delivery at the beginning of the planning period. CVRPOAT takes all the assumptions of CVRP, except the order available time, which is determined by the precedent order picking and packing stage in the warehouse of the online grocer. The objective is to minimize the sum of vehicle completion times. An efficient tabu search algorithm is presented to tackle the problem. Moreover, a Lagrangian relaxation algorithm is developed to obtain the lower bounds of reasonably sized problems. Based on the test instances derived from benchmark data, the proposed tabu search algorithm is compared with a published related genetic algorithm, as well as the derived lower bounds. Also, the tabu search algorithm is compared with the current operation strategy of the online grocer. Computational results indicate that the gap between the lower bounds and the results of the tabu search algorithm is small and the tabu search algorithm is superior to the genetic algorithm. Moreover, the CVRPOAT formulation together with the tabu search algorithm performs much better than the current operation strategy of the online grocer.

Energy-Aware Routing Protocol for Ad Hoc Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Mann Raminder P

2005-01-01

Full Text Available Wireless ad hoc sensor networks differ from wireless ad hoc networks from the following perspectives: low energy, lightweight routing protocols, and adaptive communication patterns. This paper proposes an energy-aware routing protocol (EARP suitable for ad hoc wireless sensor networks and presents an analysis for its energy consumption in various phases of route discovery and maintenance. Based on the energy consumption associated with route request processing, EARP advocates the minimization of route requests by allocating dynamic route expiry times. This paper introduces a unique mechanism for estimation of route expiry time based on the probability of route validity, which is a function of time, number of hops, and mobility parameters. In contrast to AODV, EARP reduces the repeated flooding of route requests by maintaining valid routes for longer durations.

Role of Travel Time Information on Day-to-Day Route Choice Behavior Based on Real-World Experiments

NARCIS (Netherlands)

van Essen, Mariska; Thomas, Tom; Chorus, Caspar; van Berkum, Eric C.

2016-01-01

It is widely believed that travel time information leads to reductions in traffic congestion and thereby improves network efficiency. An important research topic within travel behavior research is therefore how car drivers choose their routes, specifically when they receive travel time information.

Modeling and Solving the Multi-depot Vehicle Routing Problem with Time Window by Considering the Flexible end Depot in Each Route

Directory of Open Access Journals (Sweden)

Mohammad Mirabi

2016-11-01

Full Text Available This paper considers the multi-depot vehicle routing problem with time window in which each vehicle starts from a depot and there is no need to return to its primary depot after serving customers. The mathematical model which is developed by new approach aims to minimizing the transportation cost including the travelled distance, the latest and the earliest arrival time penalties. Furthermore, in order to reduce the problem searching space, a novel GA clustering method is developed. Finally, Experiments are run on number problems of varying depots and time window, and customer sizes. The method is compared to two other clustering techniques, fuzzy C means (FCM and K-means algorithm. Experimental results show the robustness and effectiveness of the proposed algorithm.

A granular t abu search algorithm for a real case study of a vehicle routing problem with a heterogeneous fleet and time windows

Energy Technology Data Exchange (ETDEWEB)

Bernal, Jose; Escobar, John Willmer; Linfati, Rodrigo

2017-07-01

We consider a real case study of a vehicle routing problem with a heterogeneous fleet and time windows (HFVRPTW) for a franchise company bottling Coca-Cola products in Colombia. This study aims to determine the routes to be performed to fulfill the demand of the customers by using a heterogeneous fleet and considering soft time windows. The objective is to minimize the distance traveled by the performed routes. Design/methodology/approach: We propose a two-phase heuristic algorithm. In the proposed approach, after an initial phase (first phase), a granular tabu search is applied during the improvement phase (second phase). Two additional procedures are considered to help that the algorithm could escape from local optimum, given that during a given number of iterations there has been no improvement. Findings: Computational experiments on real instances show that the proposed algorithm is able to obtain high-quality solutions within a short computing time compared to the results found by the software that the company currently uses to plan the daily routes. Originality/value: We propose a novel metaheuristic algorithm for solving a real routing problem by considering heterogeneous fleet and time windows. The efficiency of the proposed approach has been tested on real instances, and the computational experiments shown its applicability and performance for solving NP-Hard Problems related with routing problems with similar characteristics. The proposed algorithm was able to improve some of the current solutions applied by the company by reducing the route length and the number of vehicles.

A granular t abu search algorithm for a real case study of a vehicle routing problem with a heterogeneous fleet and time windows

International Nuclear Information System (INIS)

Bernal, Jose; Escobar, John Willmer; Linfati, Rodrigo

2017-01-01

We consider a real case study of a vehicle routing problem with a heterogeneous fleet and time windows (HFVRPTW) for a franchise company bottling Coca-Cola products in Colombia. This study aims to determine the routes to be performed to fulfill the demand of the customers by using a heterogeneous fleet and considering soft time windows. The objective is to minimize the distance traveled by the performed routes. Design/methodology/approach: We propose a two-phase heuristic algorithm. In the proposed approach, after an initial phase (first phase), a granular tabu search is applied during the improvement phase (second phase). Two additional procedures are considered to help that the algorithm could escape from local optimum, given that during a given number of iterations there has been no improvement. Findings: Computational experiments on real instances show that the proposed algorithm is able to obtain high-quality solutions within a short computing time compared to the results found by the software that the company currently uses to plan the daily routes. Originality/value: We propose a novel metaheuristic algorithm for solving a real routing problem by considering heterogeneous fleet and time windows. The efficiency of the proposed approach has been tested on real instances, and the computational experiments shown its applicability and performance for solving NP-Hard Problems related with routing problems with similar characteristics. The proposed algorithm was able to improve some of the current solutions applied by the company by reducing the route length and the number of vehicles.

Penetration route of functional molecules in stratum corneum studied by time-resolved small- and wide-angle x-ray diffraction

International Nuclear Information System (INIS)

Hatta, Ichiro; Ohta, Noboru; Yagi, Naoto; Nakazawa, Hiromitsu; Obata, Yasuko; Inoue, Katsuaki

2011-01-01

We studied effects of functional molecules on corneocytes in stratum corneum using time-resolved small- and wide-angle x-ray diffraction after applying a functional molecule. From these results it was revealed that in the stratum corneum a typical hydrophilic molecule, ethanol, penetrates via the transcellular route and on the other hand a typical hydrophobic molecule, d-limonene, penetrates via the intercellular route.

Search route decision of environmental monitoring at emergency time

International Nuclear Information System (INIS)

Aoyama, Isao

1979-01-01

The search route decision method is reviewed, especially the adequate arrangement of monitors in view of time in the information-gathering activity by transferring the monitors on the horizontal space after the confirmation of the abnormal release of radioactive material. As for the field of the theory of search, the developmental history is explained, namely the experiences of the naval anti submarine operation in WW-2, the salvage activities and the search problem on the sea. The kinematics for search, the probability theory for detection and the optimum distribution for search are the most important contents of the application of theory of search relating to the environmental monitoring at emergency condition. The combination of a search model consists of the peculiarity of targets, the peculiarity of observers and the standard of optimality. The peculiarity of targets is divided into the space of search, the number of targets, the way of appearance of targets and the motion of targets. The peculiarity of observers is divided into the number of observers, the divisibility of efforts for search, the credibility of search information and the search process. The standard of optimality is divided into the maximum probability of detection, the minimum risk expected and the others. Each item written above of search model is explained. Concerning the formulation of the search model, the theoretical equations for detection probability, discovery potential and instantaneous detection probability, density are derived, and these equations are evaluated and explained. The future plan is to advance the search technology so as to evaluate the detection potential to decide the route of running a monitoring car for a nuclear power plant at accidental condition. (Nakai, Y.)

Applications of a saving method with max-min ant system to a vehicle routing problem with time windows and speed limits

Directory of Open Access Journals (Sweden)

Suphan Sodsoon

2014-06-01

Full Text Available This study aims to solve a Vehicle Routing Problem with Time Windows and Speed Limits (VRPTWSL, which has received considerable attention in recent years. The vehicle routing problem with time windows is an extension of the well-known Vehicle Routing Problem (VRP and involves a fleet of vehicles set of from a depot to serve a number of customers at different geographic locations with various demands within specific time and speed limits before returning to the depot eventually. To solve the problem, an efficient Saving Method-Max Min Ant System (Saving-MMAS with Local Search algorithm is applied. Using minimization of the total transportation costs as the objective of the extension VRPTWSL, a mathematic model is constructed. Finally, the Saving-MMAS algorithms indicated the good quality of the method in this problem.

Personal continuous route pattern mining

Institute of Scientific and Technical Information of China (English)

Qian YE; Ling CHEN; Gen-cai CHEN

2009-01-01

In the daily life, people often repeat regular routes in certain periods. In this paper, a mining system is developed to find the continuous route patterns of personal past trips. In order to count the diversity of personal moving status, the mining system employs the adaptive GPS data recording and five data filters to guarantee the clean trips data. The mining system uses a client/server architecture to protect personal privacy and to reduce the computational load. The server conducts the main mining procedure but with insufficient information to recover real personal routes. In order to improve the scalability of sequential pattern mining, a novel pattern mining algorithm, continuous route pattern mining (CRPM), is proposed. This algorithm can tolerate the different disturbances in real routes and extract the frequent patterns. Experimental results based on nine persons' trips show that CRPM can extract more than two times longer route patterns than the traditional route pattern mining algorithms.

Similarity-Based Prediction of Travel Times for Vehicles Traveling on Known Routes

DEFF Research Database (Denmark)

Tiesyte, Dalia; Jensen, Christian Søndergaard

2008-01-01

, historical data in combination with real-time data may be used to predict the future travel times of vehicles more accurately, thus improving the experience of the users who rely on such information. We propose a Nearest-Neighbor Trajectory (NNT) technique that identifies the historical trajectory......The use of centralized, real-time position tracking is proliferating in the areas of logistics and public transportation. Real-time positions can be used to provide up-to-date information to a variety of users, and they can also be accumulated for uses in subsequent data analyses. In particular...... of vehicles that travel along known routes. In empirical studies with real data from buses, we evaluate how well the proposed distance functions are capable of predicting future vehicle movements. Second, we propose a main-memory index structure that enables incremental similarity search and that is capable...

Routing in Wireless Multimedia Home Networks

NARCIS (Netherlands)

Scholten, Johan; Jansen, P.G.; Hop, Laurens

This paper describes an adapted version of the destination sequenced distance vector routing protocol (DSDV) which is suitable to calculate routes in a wireless real-time home network. The home network is based on a IEEE 802.11b ad hoc network and uses a scheduled token to enforce real-time

Class network routing

Science.gov (United States)

Bhanot, Gyan [Princeton, NJ; Blumrich, Matthias A [Ridgefield, CT; Chen, Dong [Croton On Hudson, NY; Coteus, Paul W [Yorktown Heights, NY; Gara, Alan G [Mount Kisco, NY; Giampapa, Mark E [Irvington, NY; Heidelberger, Philip [Cortlandt Manor, NY; Steinmacher-Burow, Burkhard D [Mount Kisco, NY; Takken, Todd E [Mount Kisco, NY; Vranas, Pavlos M [Bedford Hills, NY

2009-09-08

Class network routing is implemented in a network such as a computer network comprising a plurality of parallel compute processors at nodes thereof. Class network routing allows a compute processor to broadcast a message to a range (one or more) of other compute processors in the computer network, such as processors in a column or a row. Normally this type of operation requires a separate message to be sent to each processor. With class network routing pursuant to the invention, a single message is sufficient, which generally reduces the total number of messages in the network as well as the latency to do a broadcast. Class network routing is also applied to dense matrix inversion algorithms on distributed memory parallel supercomputers with hardware class function (multicast) capability. This is achieved by exploiting the fact that the communication patterns of dense matrix inversion can be served by hardware class functions, which results in faster execution times.

A location-routing problem model with multiple periods and fuzzy demands

Directory of Open Access Journals (Sweden)

Ali Nadizadeh

2014-08-01

Full Text Available This paper puts forward a dynamic capacitated location-routing problem with fuzzy demands (DCLRP-FD. It is given on input a set of identical vehicles (each having a capacity, a fixed cost and availability level, a set of depots with restricted capacities and opening costs, a set of customers with fuzzy demands, and a planning horizon with multiple periods. The problem consists of determining the depots to be opened only in the first period of the planning horizon, the customers and the vehicles to be assigned to each opened depot, and performing the routes that may be changed in each time period due to fuzzy demands. A fuzzy chance-constrained programming (FCCP model has been designed using credibility theory and a hybrid heuristic algorithm with four phases is presented in order to solve the problem. To obtain the best value of the fuzzy parameters of the model and show the influence of the availability level of vehicles on final solution, some computational experiments are carried out. The validity of the model is then evaluated in contrast with CLRP-FD's models in the literature. The results indicate that the model and the proposed algorithm are robust and could be used in real world problems.

Routing strategy including time and carbon dioxide emissions : effects on network performance

NARCIS (Netherlands)

Zhang, Fan; Chen, Y.; Goni Ros, B.; GAO, Jian; Knoop, V.L.

2016-01-01

Traffic congestion leads to delays and increased carbon dioxide (CO2) emissions. Traffic management measures such as providing information on environmental route costs have been proposed to mitigate congestion. Multi-criteria routing dynamic traffic assignment (MCR-DTA) models are needed to evaluate

Routing in Wireless Multimedia Home Networks

NARCIS (Netherlands)

Scholten, Johan; Jansen, P.G.; Hop, Laurens

This paper describes an adapted version of the destination sequenced distance vector routing protocol (DSDV) which is suitable to calculate routes in a wireless ¿real-time¿ home network. The home network is based on a IEEE 802.11b ad hoc network and uses a scheduled token to enforce real-time

Clustering Using Boosted Constrained k-Means Algorithm

Directory of Open Access Journals (Sweden)

Masayuki Okabe

2018-03-01

Full Text Available This article proposes a constrained clustering algorithm with competitive performance and less computation time to the state-of-the-art methods, which consists of a constrained k-means algorithm enhanced by the boosting principle. Constrained k-means clustering using constraints as background knowledge, although easy to implement and quick, has insufficient performance compared with metric learning-based methods. Since it simply adds a function into the data assignment process of the k-means algorithm to check for constraint violations, it often exploits only a small number of constraints. Metric learning-based methods, which exploit constraints to create a new metric for data similarity, have shown promising results although the methods proposed so far are often slow depending on the amount of data or number of feature dimensions. We present a method that exploits the advantages of the constrained k-means and metric learning approaches. It incorporates a mechanism for accepting constraint priorities and a metric learning framework based on the boosting principle into a constrained k-means algorithm. In the framework, a metric is learned in the form of a kernel matrix that integrates weak cluster hypotheses produced by the constrained k-means algorithm, which works as a weak learner under the boosting principle. Experimental results for 12 data sets from 3 data sources demonstrated that our method has performance competitive to those of state-of-the-art constrained clustering methods for most data sets and that it takes much less computation time. Experimental evaluation demonstrated the effectiveness of controlling the constraint priorities by using the boosting principle and that our constrained k-means algorithm functions correctly as a weak learner of boosting.

Hypsometric amplification and routing moderation of Greenland ice sheet meltwater release

Science.gov (United States)

van As, Dirk; Mikkelsen, Andreas Bech; Holtegaard Nielsen, Morten; Box, Jason E.; Claesson Liljedahl, Lillemor; Lindbäck, Katrin; Pitcher, Lincoln; Hasholt, Bent

2017-06-01

Concurrent ice sheet surface runoff and proglacial discharge monitoring are essential for understanding Greenland ice sheet meltwater release. We use an updated, well-constrained river discharge time series from the Watson River in southwest Greenland, with an accurate, observation-based ice sheet surface mass balance model of the ˜ 12 000 km2 ice sheet area feeding the river. For the 2006-2015 decade, we find a large range of a factor of 3 in interannual variability in discharge. The amount of discharge is amplified ˜ 56 % by the ice sheet's hypsometry, i.e., area increase with elevation. A good match between river discharge and ice sheet surface meltwater production is found after introducing elevation-dependent transit delays that moderate diurnal variability in meltwater release by a factor of 10-20. The routing lag time increases with ice sheet elevation and attains values in excess of 1 week for the upper reaches of the runoff area at ˜ 1800 m above sea level. These multi-day routing delays ensure that the highest proglacial discharge levels and thus overbank flooding events are more likely to occur after multi-day melt episodes. Finally, for the Watson River ice sheet catchment, we find no evidence of meltwater storage in or release from the en- and subglacial environments in quantities exceeding our methodological uncertainty, based on the good match between ice sheet runoff and proglacial discharge.

Enhanced Contact Graph Routing (ECGR) MACHETE Simulation Model

Science.gov (United States)

Segui, John S.; Jennings, Esther H.; Clare, Loren P.

2013-01-01

Contact Graph Routing (CGR) for Delay/Disruption Tolerant Networking (DTN) space-based networks makes use of the predictable nature of node contacts to make real-time routing decisions given unpredictable traffic patterns. The contact graph will have been disseminated to all nodes before the start of route computation. CGR was designed for space-based networking environments where future contact plans are known or are independently computable (e.g., using known orbital dynamics). For each data item (known as a bundle in DTN), a node independently performs route selection by examining possible paths to the destination. Route computation could conceivably run thousands of times a second, so computational load is important. This work refers to the simulation software model of Enhanced Contact Graph Routing (ECGR) for DTN Bundle Protocol in JPL's MACHETE simulation tool. The simulation model was used for performance analysis of CGR and led to several performance enhancements. The simulation model was used to demonstrate the improvements of ECGR over CGR as well as other routing methods in space network scenarios. ECGR moved to using earliest arrival time because it is a global monotonically increasing metric that guarantees the safety properties needed for the solution's correctness since route re-computation occurs at each node to accommodate unpredicted changes (e.g., traffic pattern, link quality). Furthermore, using earliest arrival time enabled the use of the standard Dijkstra algorithm for path selection. The Dijkstra algorithm for path selection has a well-known inexpensive computational cost. These enhancements have been integrated into the open source CGR implementation. The ECGR model is also useful for route metric experimentation and comparisons with other DTN routing protocols particularly when combined with MACHETE's space networking models and Delay Tolerant Link State Routing (DTLSR) model.

Real-Time Vehicle Routing for Repairing Damaged Infrastructures Due to Natural Disasters

Directory of Open Access Journals (Sweden)

Huey-Kuo Chen

2011-01-01

Full Text Available We address the task of repairing damaged infrastructures as a series of multidepot vehicle-routing problems with time windows in a time-rolling frame. The network size of the tackled problems changes from time to time, as new disaster nodes will be added to and serviced disaster nodes will be deleted from the current network. In addition, an inaccessible disaster node would become accessible when one of its adjacent disaster nodes has been repaired. By the “take-and-conquer” strategy, the repair sequence of the disaster nodes in the affected area can be suitably scheduled. Thirteen instances were tested with our proposed heuristic, that is, Chen et al.'s approach. For comparison, Hsueh et al.'s approach (2008 with necessary modification was also tested. The results show that Chen et al.'s approach performs slightly better for larger size networks in terms of objective value.

Routing of radioactive shipments in networks with time-varying costs and curfews

Energy Technology Data Exchange (ETDEWEB)

Bowler, L.A.; Mahmassani, H.S. [Univ. of Texas, Austin, TX (United States). Dept. of Civil Engineering

1998-09-01

This research examines routing of radioactive shipments in highway networks with time-dependent travel times and population densities. A time-dependent least-cost path (TDLCP) algorithm that uses a label-correcting approach is adapted to include curfews and waiting at nodes. A method is developed to estimate time-dependent population densities, which are required to estimate risk associated with the use of a particular highway link at a particular time. The TDLCP algorithm is implemented for example networks and used to examine policy questions related to radioactive shipments. It is observed that when only Interstate highway facilities are used to transport these materials, a shipment must go through many cities and has difficulty avoiding all of them during their rush hour periods. Decreases in risk, increased departure time flexibility, and modest increases in travel times are observed when primary and/or secondary roads are included in the network. Based on the results of the example implementation, the suitability of the TDLCP algorithm for strategic nuclear material and general radioactive material shipments is demonstrated.

Routing of radioactive shipments in networks with time-varying costs and curfews

International Nuclear Information System (INIS)

Bowler, L.A.; Mahmassani, H.S.

1998-09-01

This research examines routing of radioactive shipments in highway networks with time-dependent travel times and population densities. A time-dependent least-cost path (TDLCP) algorithm that uses a label-correcting approach is adapted to include curfews and waiting at nodes. A method is developed to estimate time-dependent population densities, which are required to estimate risk associated with the use of a particular highway link at a particular time. The TDLCP algorithm is implemented for example networks and used to examine policy questions related to radioactive shipments. It is observed that when only Interstate highway facilities are used to transport these materials, a shipment must go through many cities and has difficulty avoiding all of them during their rush hour periods. Decreases in risk, increased departure time flexibility, and modest increases in travel times are observed when primary and/or secondary roads are included in the network. Based on the results of the example implementation, the suitability of the TDLCP algorithm for strategic nuclear material and general radioactive material shipments is demonstrated

Off-Line Robust Constrained MPC for Linear Time-Varying Systems with Persistent Disturbances

Directory of Open Access Journals (Sweden)

P. Bumroongsri

2014-01-01

Full Text Available An off-line robust constrained model predictive control (MPC algorithm for linear time-varying (LTV systems is developed. A novel feature is the fact that both model uncertainty and bounded additive disturbance are explicitly taken into account in the off-line formulation of MPC. In order to reduce the on-line computational burdens, a sequence of explicit control laws corresponding to a sequence of positively invariant sets is computed off-line. At each sampling time, the smallest positively invariant set containing the measured state is determined and the corresponding control law is implemented in the process. The proposed MPC algorithm can guarantee robust stability while ensuring the satisfaction of input and output constraints. The effectiveness of the proposed MPC algorithm is illustrated by two examples.

A Hybrid Chaos-Particle Swarm Optimization Algorithm for the Vehicle Routing Problem with Time Window

Directory of Open Access Journals (Sweden)

Qi Hu

2013-04-01

Full Text Available State-of-the-art heuristic algorithms to solve the vehicle routing problem with time windows (VRPTW usually present slow speeds during the early iterations and easily fall into local optimal solutions. Focusing on solving the above problems, this paper analyzes the particle encoding and decoding strategy of the particle swarm optimization algorithm, the construction of the vehicle route and the judgment of the local optimal solution. Based on these, a hybrid chaos-particle swarm optimization algorithm (HPSO is proposed to solve VRPTW. The chaos algorithm is employed to re-initialize the particle swarm. An efficient insertion heuristic algorithm is also proposed to build the valid vehicle route in the particle decoding process. A particle swarm premature convergence judgment mechanism is formulated and combined with the chaos algorithm and Gaussian mutation into HPSO when the particle swarm falls into the local convergence. Extensive experiments are carried out to test the parameter settings in the insertion heuristic algorithm and to evaluate that they are corresponding to the data’s real-distribution in the concrete problem. It is also revealed that the HPSO achieves a better performance than the other state-of-the-art algorithms on solving VRPTW.

Value of Information for Optimal Adaptive Routing in Stochastic Time-Dependent Traffic Networks: Algorithms and Computational Tools

Science.gov (United States)

2010-10-25

Real-time information is important for travelers' routing decisions in uncertain networks by enabling online adaptation to revealed traffic conditions. Usually there are spatial and/or temporal limitations in traveler information. In this research, a...

Reliable Adaptive Data Aggregation Route Strategy for a Trade-off between Energy and Lifetime in WSNs

Directory of Open Access Journals (Sweden)

Wenzhong Guo

2014-09-01

Full Text Available Mobile security is one of the most fundamental problems in Wireless Sensor Networks (WSNs. The data transmission path will be compromised for some disabled nodes. To construct a secure and reliable network, designing an adaptive route strategy which optimizes energy consumption and network lifetime of the aggregation cost is of great importance. In this paper, we address the reliable data aggregation route problem for WSNs. Firstly, to ensure nodes work properly, we propose a data aggregation route algorithm which improves the energy efficiency in the WSN. The construction process achieved through discrete particle swarm optimization (DPSO saves node energy costs. Then, to balance the network load and establish a reliable network, an adaptive route algorithm with the minimal energy and the maximum lifetime is proposed. Since it is a non-linear constrained multi-objective optimization problem, in this paper we propose a DPSO with the multi-objective fitness function combined with the phenotype sharing function and penalty function to find available routes. Experimental results show that compared with other tree routing algorithms our algorithm can effectively reduce energy consumption and trade off energy consumption and network lifetime.

Low Carbon Footprint Routes for Bird Watching

Directory of Open Access Journals (Sweden)

Wei-Ta Fang

2015-03-01

Full Text Available Bird watching is one of many recreational activities popular in ecotourism. Its popularity, therefore, prompts the need for studies on energy conservation. One such environmentally friendly approach toward minimizing bird watching’s ecological impact is ensuring a reduced carbon footprint by using an economic travel itinerary comprising a series of connected routes between tourist attractions that minimizes transit time. This study used a travel-route planning approach using geographic information systems to detect the shortest path, thereby solving the problems associated with time-consuming transport. Based on the results of road network analyses, optimal travel-route planning can be determined. These methods include simulated annealing (SA and genetic algorithms (GA. We applied two algorithms in our simulation research to detect which one is an appropriate algorithm for running carbon-routing algorithms at the regional scale. SA, which is superior to GA, is considered an excellent approach to search for the optimal path to reduce carbon dioxide and high gasoline fees, thereby controlling travel time by using the shortest travel routes.

Using Grey Wolf Algorithm to Solve the Capacitated Vehicle Routing Problem

Science.gov (United States)

Korayem, L.; Khorsid, M.; Kassem, S. S.

2015-05-01

The capacitated vehicle routing problem (CVRP) is a class of the vehicle routing problems (VRPs). In CVRP a set of identical vehicles having fixed capacities are required to fulfill customers' demands for a single commodity. The main objective is to minimize the total cost or distance traveled by the vehicles while satisfying a number of constraints, such as: the capacity constraint of each vehicle, logical flow constraints, etc. One of the methods employed in solving the CVRP is the cluster-first route-second method. It is a technique based on grouping of customers into a number of clusters, where each cluster is served by one vehicle. Once clusters are formed, a route determining the best sequence to visit customers is established within each cluster. The recently bio-inspired grey wolf optimizer (GWO), introduced in 2014, has proven to be efficient in solving unconstrained, as well as, constrained optimization problems. In the current research, our main contributions are: combining GWO with the traditional K-means clustering algorithm to generate the ‘K-GWO’ algorithm, deriving a capacitated version of the K-GWO algorithm by incorporating a capacity constraint into the aforementioned algorithm, and finally, developing 2 new clustering heuristics. The resulting algorithm is used in the clustering phase of the cluster-first route-second method to solve the CVR problem. The algorithm is tested on a number of benchmark problems with encouraging results.

A well-scalable metaheuristic for the fleet size and mix vehicle routing problem with time windows

NARCIS (Netherlands)

Bräysy, Olli; Porkka, Pasi P.; Dullaert, Wout; Repoussis, Panagiotis P.; Tarantilis, Christos D.

This paper presents an efficient and well-scalable metaheuristic for fleet size and mix vehicle routing with time windows. The suggested solution method combines the strengths of well-known threshold accepting and guided local search metaheuristics to guide a set of four local search heuristics. The

ANALYTICAL ESTIMATION OF MINIMUM AND MAXIMUM TIME EXPENDITURES OF PASSENGERS AT AN URBAN ROUTE STOP

Directory of Open Access Journals (Sweden)

Gorbachov, P.

2013-01-01

Full Text Available This scientific paper deals with the problem related to the definition of average time spent by passengers while waiting for transport vehicles at urban stops as well as the results of analytical modeling of this value at traffic schedule unknown to the passengers and of two options of the vehicle traffic management on the given route.

A Genetic Algorithm on Inventory Routing Problem

Directory of Open Access Journals (Sweden)

Nevin Aydın

2014-03-01

Full Text Available Inventory routing problem can be defined as forming the routes to serve to the retailers from the manufacturer, deciding on the quantity of the shipment to the retailers and deciding on the timing of the replenishments. The difference of inventory routing problems from vehicle routing problems is the consideration of the inventory positions of retailers and supplier, and making the decision accordingly. Inventory routing problems are complex in nature and they can be solved either theoretically or using a heuristics method. Metaheuristics is an emerging class of heuristics that can be applied to combinatorial optimization problems. In this paper, we provide the relationship between vendor-managed inventory and inventory routing problem. The proposed genetic for solving vehicle routing problem is described in detail.

MIROS: a hybrid real-time energy-efficient operating system for the resource-constrained wireless sensor nodes.

Science.gov (United States)

Liu, Xing; Hou, Kun Mean; de Vaulx, Christophe; Shi, Hongling; El Gholami, Khalid

2014-09-22

Operating system (OS) technology is significant for the proliferation of the wireless sensor network (WSN). With an outstanding OS; the constrained WSN resources (processor; memory and energy) can be utilized efficiently. Moreover; the user application development can be served soundly. In this article; a new hybrid; real-time; memory-efficient; energy-efficient; user-friendly and fault-tolerant WSN OS MIROS is designed and implemented. MIROS implements the hybrid scheduler and the dynamic memory allocator. Real-time scheduling can thus be achieved with low memory consumption. In addition; it implements a mid-layer software EMIDE (Efficient Mid-layer Software for User-Friendly Application Development Environment) to decouple the WSN application from the low-level system. The application programming process can consequently be simplified and the application reprogramming performance improved. Moreover; it combines both the software and the multi-core hardware techniques to conserve the energy resources; improve the node reliability; as well as achieve a new debugging method. To evaluate the performance of MIROS; it is compared with the other WSN OSes (TinyOS; Contiki; SOS; openWSN and mantisOS) from different OS concerns. The final evaluation results prove that MIROS is suitable to be used even on the tight resource-constrained WSN nodes. It can support the real-time WSN applications. Furthermore; it is energy efficient; user friendly and fault tolerant.

MIROS: A Hybrid Real-Time Energy-Efficient Operating System for the Resource-Constrained Wireless Sensor Nodes

Science.gov (United States)

Liu, Xing; Hou, Kun Mean; de Vaulx, Christophe; Shi, Hongling; Gholami, Khalid El

2014-01-01

Operating system (OS) technology is significant for the proliferation of the wireless sensor network (WSN). With an outstanding OS; the constrained WSN resources (processor; memory and energy) can be utilized efficiently. Moreover; the user application development can be served soundly. In this article; a new hybrid; real-time; memory-efficient; energy-efficient; user-friendly and fault-tolerant WSN OS MIROS is designed and implemented. MIROS implements the hybrid scheduler and the dynamic memory allocator. Real-time scheduling can thus be achieved with low memory consumption. In addition; it implements a mid-layer software EMIDE (Efficient Mid-layer Software for User-Friendly Application Development Environment) to decouple the WSN application from the low-level system. The application programming process can consequently be simplified and the application reprogramming performance improved. Moreover; it combines both the software and the multi-core hardware techniques to conserve the energy resources; improve the node reliability; as well as achieve a new debugging method. To evaluate the performance of MIROS; it is compared with the other WSN OSes (TinyOS; Contiki; SOS; openWSN and mantisOS) from different OS concerns. The final evaluation results prove that MIROS is suitable to be used even on the tight resource-constrained WSN nodes. It can support the real-time WSN applications. Furthermore; it is energy efficient; user friendly and fault tolerant. PMID:25248069

Optimizing well intervention routes

Energy Technology Data Exchange (ETDEWEB)

Paiva, Ronaldo O. [PETROBRAS S.A., Vitoria, ES (Brazil); Schiozer, Denis J.; Bordalo, Sergio N. [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Mecanica. Centro de Estudo do Petroleo (CEPETRO)]. E-mail: denis@dep.fem.unicamp.br; bordalo@dep.fem.unicamp.br

2000-07-01

This work presents a method for optimizing the itinerary of work over rigs, i.e., the search for the route of minimum total cost, and demonstrates the importance of the dynamics of reservoir behaviour. The total cost of a route includes the rig expenses (transport, assembly and operation), which are functions of time and distances, plus the losses of revenue in wells waiting for the rig, which are also dependent of time. A reservoir simulator is used to evaluate the monetary influence of the well shutdown on the present value of the production curve. Finally, search algorithms are employed to determine the route of minimal cost. The Simulated Annealing algorithm was also successful in optimizing the distribution of a list of wells among different work over rigs. The rational approach presented here is recommended for management teams as a standard procedure to define the priority of wells scheduled for work over. (author)

Route planning algorithms: Planific@ Project

Directory of Open Access Journals (Sweden)

Gonzalo Martín Ortega

2009-12-01

Full Text Available Planific@ is a route planning project for the city of Madrid (Spain. Its main aim is to develop an intelligence system capable of routing people from one place in the city to any other using the public transport. In order to do this, it is necessary to take into account such things as: time, traffic, user preferences, etc. Before beginning to design the project is necessary to make a comprehensive study of the variety of main known route planning algorithms suitable to be used in this project.

Continuation of Sets of Constrained Orbit Segments

DEFF Research Database (Denmark)

Schilder, Frank; Brøns, Morten; Chamoun, George Chaouki

Sets of constrained orbit segments of time continuous flows are collections of trajectories that represent a whole or parts of an invariant set. A non-trivial but simple example is a homoclinic orbit. A typical representation of this set consists of an equilibrium point of the flow and a trajectory...... that starts close and returns close to this fixed point within finite time. More complicated examples are hybrid periodic orbits of piecewise smooth systems or quasi-periodic invariant tori. Even though it is possible to define generalised two-point boundary value problems for computing sets of constrained...... orbit segments, this is very disadvantageous in practice. In this talk we will present an algorithm that allows the efficient continuation of sets of constrained orbit segments together with the solution of the full variational problem....

The Edge Set Cost of the Vehicle Routing Problem with Time Windows

DEFF Research Database (Denmark)

Reinhardt, Line Blander; Jepsen, Mads Kehlet; Pisinger, David

2016-01-01

. The certifications and investments impose a cost for the company while they also give unlimited usage of a set of roads to all vehicles belonging to the company. This violates the traditional assumption that the path between two destinations is well defined and independent of other choices. Different versions......We consider an important generalization of the vehicle routing problem with time windows in which a fixed cost must be paid for accessing a set of edges. This fixed cost could reflect payment for toll roads, investment in new facilities, the need for certifications, and other costly investments...

The Route Analysis Based On Flight Plan

Science.gov (United States)

Feriyanto, Nur; Saleh, Chairul; Fauzi, Achmad; Rachman Dzakiyullah, Nur; Riza Iwaputra, Kahfi

2016-02-01

Economic development effects use of air transportation since the business process in every aspect was increased. Many people these days was prefer using airplane because it can save time and money. This situation also effects flight routes, many airlines offer new routes to deal with competition. Managing flight routes is one of the problems that must be faced in order to find the efficient and effective routes. This paper investigates the best routes based on flight performance by determining the amount of block fuel for the Jakarta-Denpasar flight route. Moreover, in this work compares a two kinds of aircraft and tracks by calculating flight distance, flight time and block fuel. The result shows Jakarta-Denpasar in the Track II has effective and efficient block fuel that can be performed by Airbus 320-200 aircraft. This study can contribute to practice in making an effective decision, especially helping executive management of company due to selecting appropriate aircraft and the track in the flight plan based on the block fuel consumption for business operation.

Hot Routes: Developing a New Technique for the Spatial Analysis of Crime

OpenAIRE

Tompson, L.; Partridge, H.; Shepherd, N.

2009-01-01

The use of hotspot mapping techniques such as KDE to represent the geographical spread of linear events can be problematic. Network-constrained data (for example transport-related crime) require a different approach to visualize concentration. We propose a methodology called Hot Routes, which measures the risk distribution of crime along a linear network by calculating the rate of crimes per section of road. This method has been designed for everyday crime analysts, and requires only a Geogra...

Aircraft route forecasting under adverse weather conditions

Directory of Open Access Journals (Sweden)

Thomas Hauf

2017-04-01

Full Text Available In this paper storm nowcasts in the terminal manoeuvring area (TMA of Hong Kong International Airport are used to forecast deviation routes through a field of storms for arriving and departing aircraft. Storms were observed and nowcast by the nowcast system SWIRLS from the Hong Kong Observatory. Storms were considered as no-go zones for aircraft and deviation routes were determined with the DIVSIM software package. Two days (21 and 22 May 2011 with 22 actual flown routes were investigated. Flights were simulated with a nowcast issued at the time an aircraft entered the TMA or departed from the airport. These flights were compared with a posteriori simulations, in which all storm fields were known and circumnavigated. Both types of simulated routes were then compared with the actual flown routes. The qualitative comparison of the various routes revealed generally good agreement. Larger differences were found in more complex situations with many active storms in the TMA. Route differences resulted primarily from air traffic control measures imposed such as holdings, slow-downs and shortcuts, causing the largest differences between the estimated and actual landing time. Route differences could be enhanced as aircraft might be forced to circumnavigate a storm ahead in a different sense. The use of route forecasts to assist controllers coordinating flights in a complex moving storm field is discussed. The study emphasises the important application of storm nowcasts in aviation meteorology.

Modified artificial bee colony for the vehicle routing problems with time windows.

Science.gov (United States)

Alzaqebah, Malek; Abdullah, Salwani; Jawarneh, Sana

2016-01-01

The natural behaviour of the honeybee has attracted the attention of researchers in recent years and several algorithms have been developed that mimic swarm behaviour to solve optimisation problems. This paper introduces an artificial bee colony (ABC) algorithm for the vehicle routing problem with time windows (VRPTW). A Modified ABC algorithm is proposed to improve the solution quality of the original ABC. The high exploration ability of the ABC slows-down its convergence speed, which may due to the mechanism used by scout bees in replacing abandoned (unimproved) solutions with new ones. In the Modified ABC a list of abandoned solutions is used by the scout bees to memorise the abandoned solutions, then the scout bees select a solution from the list based on roulette wheel selection and replace by a new solution with random routs selected from the best solution. The performance of the Modified ABC is evaluated on Solomon benchmark datasets and compared with the original ABC. The computational results demonstrate that the Modified ABC outperforms the original ABC also produce good solutions when compared with the best-known results in the literature. Computational investigations show that the proposed algorithm is a good and promising approach for the VRPTW.

Cell therapy attenuates cardiac dysfunction post myocardial infarction: effect of timing, routes of injection and a fibrin scaffold.

Directory of Open Access Journals (Sweden)

Juliana S Nakamuta

Full Text Available BACKGROUND: Cell therapy approaches for biologic cardiac repair hold great promises, although basic fundamental issues remain poorly understood. In the present study we examined the effects of timing and routes of administration of bone marrow cells (BMC post-myocardial infarction (MI and the efficacy of an injectable biopolymer scaffold to improve cardiac cell retention and function. METHODOLOGY/PRINCIPAL FINDINGS: (99mTc-labeled BMC (6 x 10(6 cells were injected by 4 different routes in adult rats: intravenous (IV, left ventricular cavity (LV, left ventricular cavity with temporal aorta occlusion (LV(+ to mimic coronary injection, and intramyocardial (IM. The injections were performed 1, 2, 3, or 7 days post-MI and cell retention was estimated by gamma-emission counting of the organs excised 24 hs after cell injection. IM injection improved cell retention and attenuated cardiac dysfunction, whereas IV, LV or LV* routes were somewhat inefficient (<1%. Cardiac BMC retention was not influenced by timing except for the IM injection that showed greater cell retention at 7 (16% vs. 1, 2 or 3 (average of 7% days post-MI. Cardiac cell retention was further improved by an injectable fibrin scaffold at day 3 post-MI (17 vs. 7%, even though morphometric and function parameters evaluated 4 weeks later displayed similar improvements. CONCLUSIONS/SIGNIFICANCE: These results show that cells injected post-MI display comparable tissue distribution profile regardless of the route of injection and that there is no time effect for cardiac cell accumulation for injections performed 1 to 3 days post-MI. As expected the IM injection is the most efficient for cardiac cell retention, it can be further improved by co-injection with a fibrin scaffold and it significantly attenuates cardiac dysfunction evaluated 4 weeks post myocardial infarction. These pharmacokinetic data obtained under similar experimental conditions are essential for further development of these

Preparation and biological evaluation of conformationally constrained BACE1 inhibitors.

Science.gov (United States)

Winneroski, Leonard L; Schiffler, Matthew A; Erickson, Jon A; May, Patrick C; Monk, Scott A; Timm, David E; Audia, James E; Beck, James P; Boggs, Leonard N; Borders, Anthony R; Boyer, Robert D; Brier, Richard A; Hudziak, Kevin J; Klimkowski, Valentine J; Garcia Losada, Pablo; Mathes, Brian M; Stout, Stephanie L; Watson, Brian M; Mergott, Dustin J

2015-07-01

The BACE1 enzyme is a key target for Alzheimer's disease. During our BACE1 research efforts, fragment screening revealed that bicyclic thiazine 3 had low millimolar activity against BACE1. Analysis of the co-crystal structure of 3 suggested that potency could be increased through extension toward the S3 pocket and through conformational constraint of the thiazine core. Pursuit of S3-binding groups produced low micromolar inhibitor 6, which informed the S3-design for constrained analogs 7 and 8, themselves prepared via independent, multi-step synthetic routes. Biological characterization of BACE inhibitors 6-8 is described. Copyright © 2015 Elsevier Ltd. All rights reserved.

Hypsometric amplification and routing moderation of Greenland ice sheet meltwater release

Directory of Open Access Journals (Sweden)

D. van As

2017-06-01

Full Text Available Concurrent ice sheet surface runoff and proglacial discharge monitoring are essential for understanding Greenland ice sheet meltwater release. We use an updated, well-constrained river discharge time series from the Watson River in southwest Greenland, with an accurate, observation-based ice sheet surface mass balance model of the  ∼  12 000 km2 ice sheet area feeding the river. For the 2006–2015 decade, we find a large range of a factor of 3 in interannual variability in discharge. The amount of discharge is amplified  ∼  56 % by the ice sheet's hypsometry, i.e., area increase with elevation. A good match between river discharge and ice sheet surface meltwater production is found after introducing elevation-dependent transit delays that moderate diurnal variability in meltwater release by a factor of 10–20. The routing lag time increases with ice sheet elevation and attains values in excess of 1 week for the upper reaches of the runoff area at  ∼  1800 m above sea level. These multi-day routing delays ensure that the highest proglacial discharge levels and thus overbank flooding events are more likely to occur after multi-day melt episodes. Finally, for the Watson River ice sheet catchment, we find no evidence of meltwater storage in or release from the en- and subglacial environments in quantities exceeding our methodological uncertainty, based on the good match between ice sheet runoff and proglacial discharge.

Route-Based Signal Preemption Control of Emergency Vehicle

Directory of Open Access Journals (Sweden)

Haibo Mu

2018-01-01

Full Text Available This paper focuses on the signal preemption control of emergency vehicles (EV. A signal preemption control method based on route is proposed to reduce time delay of EV at intersections. According to the time at which EV is detected and the current phase of each intersection on the travelling route of EV, the calculation methods of the earliest start time and the latest start time of green light at each intersection are given. Consequently, the effective time range of green light at each intersection is determined in theory. A multiobjective programming model, whose objectives are the minimal residence time of EV at all intersections and the maximal passing numbers of general society vehicles, is presented. Finally, a simulation calculation is carried out. Calculation results indicate that, by adopting the signal preemption method based on route, the delay of EV is reduced and the number of society vehicles passing through the whole system is increased. The signal preemption control method of EV based on route can reduce the time delay of EV and improve the evacuation efficiency of the system.

Identification of Constrained Cancer Driver Genes Based on Mutation Timing

Science.gov (United States)

Sakoparnig, Thomas; Fried, Patrick; Beerenwinkel, Niko

2015-01-01

Cancer drivers are genomic alterations that provide cells containing them with a selective advantage over their local competitors, whereas neutral passengers do not change the somatic fitness of cells. Cancer-driving mutations are usually discriminated from passenger mutations by their higher degree of recurrence in tumor samples. However, there is increasing evidence that many additional driver mutations may exist that occur at very low frequencies among tumors. This observation has prompted alternative methods for driver detection, including finding groups of mutually exclusive mutations and incorporating prior biological knowledge about gene function or network structure. Dependencies among drivers due to epistatic interactions can also result in low mutation frequencies, but this effect has been ignored in driver detection so far. Here, we present a new computational approach for identifying genomic alterations that occur at low frequencies because they depend on other events. Unlike passengers, these constrained mutations display punctuated patterns of occurrence in time. We test this driver–passenger discrimination approach based on mutation timing in extensive simulation studies, and we apply it to cross-sectional copy number alteration (CNA) data from ovarian cancer, CNA and single-nucleotide variant (SNV) data from breast tumors and SNV data from colorectal cancer. Among the top ranked predicted drivers, we find low-frequency genes that have already been shown to be involved in carcinogenesis, as well as many new candidate drivers. The mutation timing approach is orthogonal and complementary to existing driver prediction methods. It will help identifying from cancer genome data the alterations that drive tumor progression. PMID:25569148

Privacy-Preserving Interdomain Routing at Internet Scale

Directory of Open Access Journals (Sweden)

Asharov Gilad

2017-07-01

Full Text Available The Border Gateway Protocol (BGP computes routes between the organizational networks that make up today’s Internet. Unfortunately, BGP suffers from deficiencies, including slow convergence, security problems, a lack of innovation, and the leakage of sensitive information about domains’ routing preferences. To overcome some of these problems, we revisit the idea of centralizing and using secure multi-party computation (MPC for interdomain routing which was proposed by Gupta et al. (ACM HotNets’12. We implement two algorithms for interdomain routing with state-of-the-art MPC protocols. On an empirically derived dataset that approximates the topology of today’s Internet (55 809 nodes, our protocols take as little as 6 s of topology-independent precomputation and only 3 s of online time. We show, moreover, that when our MPC approach is applied at country/region-level scale, runtimes can be as low as 0.17 s online time and 0.20 s pre-computation time. Our results motivate the MPC approach for interdomain routing and furthermore demonstrate that current MPC techniques are capable of efficiently tackling real-world problems at a large scale.

'Football Fitness': constraining and enabling possibilities for the management of leisure time for women

DEFF Research Database (Denmark)

Thing, Lone Friis; Hybholt, Maria Gliemann; Jensen, Andorra Lynn

2017-01-01

The aim of the article is to identify constraining and enabling aspects for the management of leisure time for women participating in ‘Football Fitness’, a new ‘sport for all programme’ carried out in associative sport clubs in Denmark. The article is based on six focus group interviews with white......, middle-class female participants (N = 32, aged 27–56). An analysis combining Hochschild’s conceptualization of the second and third shift [1989. The Second Shift. New York: Avon] with Elias and Dunning’s perspective on leisure as part of the spare-time spectrum and leisure sport as a quest for excitement...... [1986. Quest for Excitement. Sport and Leisure in the Civilizing Process. New York: Basil Blackwell] demonstrates that leisure sport participation must be understood in relation to both spare time, family life, and work life, as these spheres are interrelated. According to the women, both doing...

Feasible Initial Population with Genetic Diversity for a Population-Based Algorithm Applied to the Vehicle Routing Problem with Time Windows

Directory of Open Access Journals (Sweden)

Marco Antonio Cruz-Chávez

2016-01-01

Full Text Available A stochastic algorithm for obtaining feasible initial populations to the Vehicle Routing Problem with Time Windows is presented. The theoretical formulation for the Vehicle Routing Problem with Time Windows is explained. The proposed method is primarily divided into a clustering algorithm and a two-phase algorithm. The first step is the application of a modified k-means clustering algorithm which is proposed in this paper. The two-phase algorithm evaluates a partial solution to transform it into a feasible individual. The two-phase algorithm consists of a hybridization of four kinds of insertions which interact randomly to obtain feasible individuals. It has been proven that different kinds of insertions impact the diversity among individuals in initial populations, which is crucial for population-based algorithm behavior. A modification to the Hamming distance method is applied to the populations generated for the Vehicle Routing Problem with Time Windows to evaluate their diversity. Experimental tests were performed based on the Solomon benchmarking. Experimental results show that the proposed method facilitates generation of highly diverse populations, which vary according to the type and distribution of the instances.

Identification of Robust Terminal-Area Routes in Convective Weather

Science.gov (United States)

Pfeil, Diana Michalek; Balakrishnan, Hamsa

2012-01-01

Convective weather is responsible for large delays and widespread disruptions in the U.S. National Airspace System, especially during summer. Traffic flow management algorithms require reliable forecasts of route blockage to schedule and route traffic. This paper demonstrates how raw convective weather forecasts, which provide deterministic predictions of the vertically integrated liquid (the precipitation content in a column of airspace) can be translated into probabilistic forecasts of whether or not a terminal area route will be blocked. Given a flight route through the terminal area, we apply techniques from machine learning to determine the likelihood that the route will be open in actual weather. The likelihood is then used to optimize terminalarea operations by dynamically moving arrival and departure routes to maximize the expected capacity of the terminal area. Experiments using real weather scenarios on stormy days show that our algorithms recommend that a terminal-area route be modified 30% of the time, opening up 13% more available routes that were forecast to be blocked during these scenarios. The error rate is low, with only 5% of cases corresponding to a modified route being blocked in reality, whereas the original route is in fact open. In addition, for routes predicted to be open with probability 0.95 or greater by our method, 96% of these routes (on average over time horizon) are indeed open in the weather that materializes

Fatigue mitigation effects of en-route napping on commercial airline pilots flying international routes

Science.gov (United States)

Baldwin, Jarret Taylor

The introduction of ultra-long range commercial aircraft and the evolution of the commercial airline industry has provided new opportunities for air carriers to fly longer range international route segments while deregulation, industry consolidation, and the constant drive to reduce costs wherever possible has pressured airline managements to seek more productivity from their pilots. At the same time, advancements in the understanding of human physiology have begun to make their way into flight and duty time regulations and airline scheduling practices. In this complex and ever changing operating environment, there remains an essential need to better understand how these developments, and other daily realities facing commercial airline pilots, are affecting their fatigue management strategies as they go about their rituals of getting to and from their homes to work and performing their flight assignments. Indeed, the need for commercial airline pilots to have access to better and more effective fatigue mitigation tools to combat fatigue and insure that they are well rested and at the top of their game when flying long-range international route segments has never been greater. This study examined to what extent the maximum fatigue states prior to napping, as self-accessed by commercial airline pilots flying international route segments, were affected by a number of other common flight assignment related factors. The study also examined to what extent the availability of scheduled en-route rest opportunities, in an onboard crew rest facility, affected the usage of en-route napping as a fatigue mitigation strategy, and to what extent the duration of such naps affected the perceived benefits of such naps as self-accessed by commercial airline pilots flying international route segments. The study utilized an online survey tool to collect data on crew position, prior flight segments flown in the same duty period, augmentation, commuting, pre-flight rest obtained in the

Mathematical Formulation and Comparison of Solution Approaches for the Vehicle Routing Problem with Access Time Windows

Directory of Open Access Journals (Sweden)

Rafael Grosso

2018-01-01

Full Text Available The application of the principles of sustainability to the implementation of urban freight policies requires the estimation of all the costs and externalities involved. We focus here on the case of access time windows, which ban the access of freight vehicles to central urban areas in many European cities. Even though this measure seeks to reduce congestion and emissions in the most crowded periods of the day, it also imposes additional costs for carriers and results in higher emissions and energy consumption. We present here a mathematical model for the Vehicle Routing Problem with Access Time Windows, a variant of the VRP suitable for planning delivery routes in a city subject to this type of accessibility restriction. We use the model to find exact solutions to small problem instances based on a case study and then compare the performance over larger instances of a modified savings algorithm, a genetic algorithm, and a tabu search procedure, with the results showing no clear prevalence of any of them, but confirming the significance of those additional costs and externalities.

A Combination of Genetic Algorithm and Particle Swarm Optimization for Vehicle Routing Problem with Time Windows.

Science.gov (United States)

Xu, Sheng-Hua; Liu, Ji-Ping; Zhang, Fu-Hao; Wang, Liang; Sun, Li-Jian

2015-08-27

A combination of genetic algorithm and particle swarm optimization (PSO) for vehicle routing problems with time windows (VRPTW) is proposed in this paper. The improvements of the proposed algorithm include: using the particle real number encoding method to decode the route to alleviate the computation burden, applying a linear decreasing function based on the number of the iterations to provide balance between global and local exploration abilities, and integrating with the crossover operator of genetic algorithm to avoid the premature convergence and the local minimum. The experimental results show that the proposed algorithm is not only more efficient and competitive with other published results but can also obtain more optimal solutions for solving the VRPTW issue. One new well-known solution for this benchmark problem is also outlined in the following.

Proxies for Anonymous Routing

National Research Council Canada - National Science Library

Reed, Michael G; Syverson, Paul F; Goldschlag, David M

1996-01-01

...), and file transfers (FTP) have been implemented. Onion routing provides application independent, real-time, and bi-directional anonymous connections that are resistant to both eavesdropping and traffic analysis...

Emission control with route optimization in solid waste collection ...

Indian Academy of Sciences (India)

system is used, route distance and route time will be decreased by 24·6% and. 44·3% as ... Keywords. Exhaust emission; route optimization; solid waste collection; GIS, .... Catchment areas for a sales campaign can be analysed. Customers ...

Energy-Efficient Cluster Based Routing Protocol in Mobile Ad Hoc Networks Using Network Coding

OpenAIRE

Srinivas Kanakala; Venugopal Reddy Ananthula; Prashanthi Vempaty

2014-01-01

In mobile ad hoc networks, all nodes are energy constrained. In such situations, it is important to reduce energy consumption. In this paper, we consider the issues of energy efficient communication in MANETs using network coding. Network coding is an effective method to improve the performance of wireless networks. COPE protocol implements network coding concept to reduce number of transmissions by mixing the packets at intermediate nodes. We incorporate COPE into cluster based routing proto...

Routing Optimization of Intelligent Vehicle in Automated Warehouse

Directory of Open Access Journals (Sweden)

Yan-cong Zhou

2014-01-01

Full Text Available Routing optimization is a key technology in the intelligent warehouse logistics. In order to get an optimal route for warehouse intelligent vehicle, routing optimization in complex global dynamic environment is studied. A new evolutionary ant colony algorithm based on RFID and knowledge-refinement is proposed. The new algorithm gets environmental information timely through the RFID technology and updates the environment map at the same time. It adopts elite ant kept, fallback, and pheromones limitation adjustment strategy. The current optimal route in population space is optimized based on experiential knowledge. The experimental results show that the new algorithm has higher convergence speed and can jump out the U-type or V-type obstacle traps easily. It can also find the global optimal route or approximate optimal one with higher probability in the complex dynamic environment. The new algorithm is proved feasible and effective by simulation results.

Route Network Construction with Location-Direction-Enabled Photographs

Science.gov (United States)

Fujita, Hideyuki; Sagara, Shota; Ohmori, Tadashi; Shintani, Takahiko

2018-05-01

We propose a method for constructing a geometric graph for generating routes that summarize a geographical area and also have visual continuity by using a set of location-direction-enabled photographs. A location- direction-enabled photograph is a photograph that has information about the location (position of the camera at the time of shooting) and the direction (direction of the camera at the time of shooting). Each nodes of the graph corresponds to a location-direction-enabled photograph. The location of each node is the location of the corresponding photograph, and a route on the graph corresponds to a route in the geographic area and a sequence of photographs. The proposed graph is constructed to represent characteristic spots and paths linking the spots, and it is assumed to be a kind of a spatial summarization of the area with the photographs. Therefore, we call the routes on the graph as spatial summary route. Each route on the proposed graph also has a visual continuity, which means that we can understand the spatial relationship among the continuous photographs on the route such as moving forward, backward, turning right, etc. In this study, when the changes in the shooting position and shooting direction satisfied a given threshold, the route was defined to have visual continuity. By presenting the photographs in order along the generated route, information can be presented sequentially, while maintaining visual continuity to a great extent.

Analysis of the effect of the Electron-Beam welding sequence for a fixed manufacturing route using finite element simulations applied to ITER vacuum vessel manufacture

Energy Technology Data Exchange (ETDEWEB)

Martín-Menéndez, Cristina, E-mail: cristina@natec-ingenieros.com [Numerical Analysis Technologies, S.L. Marqués de San Esteban No. 52, 33206 Gijón (Spain); Rodríguez, Eduardo [Department of Mechanical Engineering, University of Oviedo, Campus de Gijón, 33203 Gijón (Spain); Ottolini, Marco [Ansaldo Nucleare S.p.A., Corso Perrone 25, 16152 Genova (Italy); Caixas, Joan [F4E, c/Josep Pla, n.2, Torres Diagonal Litoral, Edificio B3, E-08019 Barcelona (Spain); Guirao, Julio [Numerical Analysis Technologies, S.L. Marqués de San Esteban No. 52, 33206 Gijón (Spain)

2016-03-15

Highlights: • The simulation methodology employed in this paper is able to adapt inside a complex manufacturing route. • The effect of the sequence is lower in a highly constrained assembly than in a lowly constrained one. • The most relevant influence on the distortions is the jigs design, instead of the welding sequence. • The welding distortion analysis should be used as a guidance to design and improve the manufacturing strategy. - Abstract: The ITER Vacuum Vessel Sectors have very tight tolerances and high density of welding. Therefore, prediction and reduction of welding distortion are critical to allow the final assembly with the other Vacuum Vessel Sectors without the production of a full scale prototype. In this paper, the effect of the welding sequence in the distortions inside a fixed manufacturing route and in a highly constrained assembly is studied in the poloidal segment named inboard (PS1). This is one of the four poloidal segments (PS) assembled for the sector. Moreover, some restrictions and limitations in the welding sequence related to the manufacturing process are explained. The results obtained show that the effect of the sequence is lower in a highly constrained assembly than in a low constrained one. A prototype manufactured by AMW consortium (PS1 mock-up) is used in order to validate the finite element method welding simulation employed. The obtained results confirmed that for Electron-Beam welds, both the welding simulation and the mock-up show a low value of distortions.

On line routing per mobile phone

DEFF Research Database (Denmark)

Bieding, Thomas; Görtz, Simon; Klose, Andreas

2009-01-01

On-line routing is concerned with building vehicle routes in an ongoing fashion in such a way that customer requests arriving dynamically in time are efficiently and effectively served. An indispensable prerequisite for applying on-line routing methods is mobile communication technology....... Additionally it is of utmost importance that the employed communication system is suitable integrated with the firm’s enterprise application system and business processes. On basis of a case study, we describe in this paper a system that is cheap and easy to implement due to the use of simple mobile phones...

Influence of capacity- and time-constrained intermediate storage in two-stage food production systems

DEFF Research Database (Denmark)

Akkerman, Renzo; van Donk, Dirk Pieter; Gaalman, Gerard

2007-01-01

In food processing, two-stage production systems with a batch processor in the first stage and packaging lines in the second stage are common and mostly separated by capacity- and time-constrained intermediate storage. This combination of constraints is common in practice, but the literature hardly...... of systems like this. Contrary to the common sense in operations management, the LPT rule is able to maximize the total production volume per day. Furthermore, we show that adding one tank has considerable effects. Finally, we conclude that the optimal setup frequency for batches in the first stage...... pays any attention to this. In this paper, we show how various capacity and time constraints influence the performance of a specific two-stage system. We study the effects of several basic scheduling and sequencing rules in the presence of these constraints in order to learn the characteristics...

Benefits Analysis of Multi-Center Dynamic Weather Routes

Science.gov (United States)

Sheth, Kapil; McNally, David; Morando, Alexander; Clymer, Alexis; Lock, Jennifer; Petersen, Julien

2014-01-01

Dynamic weather routes are flight plan corrections that can provide airborne flights more than user-specified minutes of flying-time savings, compared to their current flight plan. These routes are computed from the aircraft's current location to a flight plan fix downstream (within a predefined limit region), while avoiding forecasted convective weather regions. The Dynamic Weather Routes automation has been continuously running with live air traffic data for a field evaluation at the American Airlines Integrated Operations Center in Fort Worth, TX since July 31, 2012, where flights within the Fort Worth Air Route Traffic Control Center are evaluated for time savings. This paper extends the methodology to all Centers in United States and presents benefits analysis of Dynamic Weather Routes automation, if it was implemented in multiple airspace Centers individually and concurrently. The current computation of dynamic weather routes requires a limit rectangle so that a downstream capture fix can be selected, preventing very large route changes spanning several Centers. In this paper, first, a method of computing a limit polygon (as opposed to a rectangle used for Fort Worth Center) is described for each of the 20 Centers in the National Airspace System. The Future ATM Concepts Evaluation Tool, a nationwide simulation and analysis tool, is used for this purpose. After a comparison of results with the Center-based Dynamic Weather Routes automation in Fort Worth Center, results are presented for 11 Centers in the contiguous United States. These Centers are generally most impacted by convective weather. A breakdown of individual Center and airline savings is presented and the results indicate an overall average savings of about 10 minutes of flying time are obtained per flight.

Finite-time convergent recurrent neural network with a hard-limiting activation function for constrained optimization with piecewise-linear objective functions.

Science.gov (United States)

Liu, Qingshan; Wang, Jun

2011-04-01

This paper presents a one-layer recurrent neural network for solving a class of constrained nonsmooth optimization problems with piecewise-linear objective functions. The proposed neural network is guaranteed to be globally convergent in finite time to the optimal solutions under a mild condition on a derived lower bound of a single gain parameter in the model. The number of neurons in the neural network is the same as the number of decision variables of the optimization problem. Compared with existing neural networks for optimization, the proposed neural network has a couple of salient features such as finite-time convergence and a low model complexity. Specific models for two important special cases, namely, linear programming and nonsmooth optimization, are also presented. In addition, applications to the shortest path problem and constrained least absolute deviation problem are discussed with simulation results to demonstrate the effectiveness and characteristics of the proposed neural network.

Route-external and route-internal landmarks in route descriptions : Effects of route length and map design

NARCIS (Netherlands)

Westerbeek, Hans; Maes, Alfons

2013-01-01

Landmarks are basic ingredients in route descriptions. They often mark choice points: locations where travellers choose from different options how to continue the route. This study focuses on one of the loose ends in the taxonomy of landmarks. In a memory-based production experiment in which

Assessing green waste route by using Network Analysis

Science.gov (United States)

Hasmantika, I. H.; Maryono, M.

2018-02-01

Green waste, such as waste from park need treat proper. One of the main problems of green waste management is how to design optimum collection. This research aims to determine the optimum green waste collection by determining optimum route among park. The route optimum was assessed by using network analysis method. And the region five of Semarang city’s park within 20 parks in chose as case study. To enhancing recycle of green waste, three scenarios of treatment are proposed. Scenario 1 used one integrated treatment facility as terminal for enhancing recycle of green waste, Scenario 2 used two sites and scenario 3 used three sites. According to the assessment, the length of route of scenario 1 is 36.126 km and the time for collection estimated is 46 minutes. In scenario 2, the length of route is 36.471 km with a travel time is 47 minutes. The length of scenario three is 46.934 km and the time of collection is 60 minutes.

User habits and multimodal route planning

Directory of Open Access Journals (Sweden)

Géza Katona

2017-10-01

Full Text Available The results of route planning researches are monitored by logistic and automotive industries. The economic aspects of the cost saving are in the focus of the attention. An optimal route could cause time or fuel savings. An effective driving or an optimal route is a good basis to achieve an economical aim. Moreover the spread of new automotive solutions especially in case of electric cars the optimisation has particular significance regarding the limited battery storage. Additionally the autonomous car development could not be neglected. As a result the society could expect safer roads, better space usage and effective resource management. Nevertheless the requirements of users are extremely diverse, which is not negligible. Supporting these aims, in this paper the connection between the multimodal route planning and the user requirements are investigated. The examination is focused to a sensitivity analysis and a survey to evaluate the data and support the settings of a user habit effect to the final route.

Delay Management with Re-Routing of Passengers

NARCIS (Netherlands)

T.A.B. Dollevoet (Twan); D. Huisman (Dennis); M.E. Schmidt (Marie); A. Schöbel (Anita)

2010-01-01

textabstractThe question of delay management is whether trains should wait for a delayed feeder train or should depart on time. In classical delay management models passengers always take their originally planned route. In this paper, we propose a model where re-routing of passengers is

Coordinated Platoon Routing in a Metropolitan Network

Energy Technology Data Exchange (ETDEWEB)

Larson, Jeffrey; Munson, Todd; Sokolov, Vadim

2016-10-10

Platooning vehicles—connected and automated vehicles traveling with small intervehicle distances—use less fuel because of reduced aerodynamic drag. Given a network de- fined by vertex and edge sets and a set of vehicles with origin/destination nodes/times, we model and solve the combinatorial optimization problem of coordinated routing of vehicles in a manner that routes them to their destination on time while using the least amount of fuel. Common approaches decompose the platoon coordination and vehicle routing into separate problems. Our model addresses both problems simultaneously to obtain the best solution. We use modern modeling techniques and constraints implied from analyzing the platoon routing problem to address larger numbers of vehicles and larger networks than previously considered. While the numerical method used is unable to certify optimality for candidate solutions to all networks and parameters considered, we obtain excellent solutions in approximately one minute for much larger networks and vehicle sets than previously considered in the literature.

A multiple ship routing and speed optimization problem under time, cost and environmental objectives

DEFF Research Database (Denmark)

Wen, M.; Pacino, Dario; Kontovas, C.A.

2017-01-01

The purpose of this paper is to investigate a multiple ship routing and speed optimization problem under time, cost and environmental objectives. A branch and price algorithm as well as a constraint programming model are developed that consider (a) fuel consumption as a function of payload, (b......) fuel price as an explicit input, (c) freight rate as an input, and (d) in-transit cargo inventory costs. The alternative objective functions are minimum total trip duration, minimum total cost and minimum emissions. Computational experience with the algorithm is reported on a variety of scenarios....

DRO: domain-based route optimization scheme for nested mobile networks

Directory of Open Access Journals (Sweden)

Chuang Ming-Chin

2011-01-01

Full Text Available Abstract The network mobility (NEMO basic support protocol is designed to support NEMO management, and to ensure communication continuity between nodes in mobile networks. However, in nested mobile networks, NEMO suffers from the pinball routing problem, which results in long packet transmission delays. To solve the problem, we propose a domain-based route optimization (DRO scheme that incorporates a domain-based network architecture and ad hoc routing protocols for route optimization. DRO also improves the intra-domain handoff performance, reduces the convergence time during route optimization, and avoids the out-of-sequence packet problem. A detailed performance analysis and simulations were conducted to evaluate the scheme. The results demonstrate that DRO outperforms existing mechanisms in terms of packet transmission delay (i.e., better route-optimization, intra-domain handoff latency, convergence time, and packet tunneling overhead.

Automated Flight Routing Using Stochastic Dynamic Programming

Science.gov (United States)

Ng, Hok K.; Morando, Alex; Grabbe, Shon

2010-01-01

Airspace capacity reduction due to convective weather impedes air traffic flows and causes traffic congestion. This study presents an algorithm that reroutes flights in the presence of winds, enroute convective weather, and congested airspace based on stochastic dynamic programming. A stochastic disturbance model incorporates into the reroute design process the capacity uncertainty. A trajectory-based airspace demand model is employed for calculating current and future airspace demand. The optimal routes minimize the total expected traveling time, weather incursion, and induced congestion costs. They are compared to weather-avoidance routes calculated using deterministic dynamic programming. The stochastic reroutes have smaller deviation probability than the deterministic counterpart when both reroutes have similar total flight distance. The stochastic rerouting algorithm takes into account all convective weather fields with all severity levels while the deterministic algorithm only accounts for convective weather systems exceeding a specified level of severity. When the stochastic reroutes are compared to the actual flight routes, they have similar total flight time, and both have about 1% of travel time crossing congested enroute sectors on average. The actual flight routes induce slightly less traffic congestion than the stochastic reroutes but intercept more severe convective weather.

Development of safe routes for children in urban environment

Science.gov (United States)

Koryagin, M. E.; Medvedev, V. I.; Strykov, P. G.

2018-01-01

The matter of development of safe travel routes for children between school and home is analyzed. The availability of various applications and devices to identify the location of the child and his/her travel routes is noted. The main factors to be taken into account when planning children travel routes are described. The most popular Russian services for route planning, Google, Yandex, and 2GIS, are discussed. These services are shown to have a number of shortcomings which does not allow them to choose really safe routes. A decision on making the route selection by two criteria (the travel time and the probability of an accident) is obtained. As a numerical example, the Pareto area for possible routes is constructed.

Factorization of Constrained Energy K-Network Reliability with Perfect Nodes

OpenAIRE

Burgos, Juan Manuel

2013-01-01

This paper proves a new general K-network constrained energy reliability global factorization theorem. As in the unconstrained case, beside its theoretical mathematical importance the theorem shows how to do parallel processing in exact network constrained energy reliability calculations in order to reduce the processing time of this NP-hard problem. Followed by a new simple factorization formula for its calculation, we propose a new definition of constrained energy network reliability motiva...

A Simulation-Based Dynamic Stochastic Route Choice Model for Evacuation

Directory of Open Access Journals (Sweden)

Xing Zhao

2012-01-01

Full Text Available This paper establishes a dynamic stochastic route choice model for evacuation to simulate the propagation process of traffic flow and estimate the stochastic route choice under evacuation situations. The model contains a lane-group-based cell transmission model (CTM which sets different traffic capacities for links with different turning movements to flow out in an evacuation situation, an actual impedance model which is to obtain the impedance of each route in time units at each time interval and a stochastic route choice model according to the probit-based stochastic user equilibrium. In this model, vehicles loading at each origin at each time interval are assumed to choose an evacuation route under determinate road network, signal design, and OD demand. As a case study, the proposed model is validated on the network nearby Nanjing Olympic Center after the opening ceremony of the 10th National Games of the People's Republic of China. The traffic volumes and clearing time at five exit points of the evacuation zone are calculated by the model to compare with survey data. The results show that this model can appropriately simulate the dynamic route choice and evolution process of the traffic flow on the network in an evacuation situation.

Metro passengers’ route choice model and its application considering perceived transfer threshold

Science.gov (United States)

Jin, Fanglei; Zhang, Yongsheng; Liu, Shasha

2017-01-01

With the rapid development of the Metro network in China, the greatly increased route alternatives make passengers’ route choice behavior and passenger flow assignment more complicated, which presents challenges to the operation management. In this paper, a path sized logit model is adopted to analyze passengers’ route choice preferences considering such parameters as in-vehicle time, number of transfers, and transfer time. Moreover, the “perceived transfer threshold” is defined and included in the utility function to reflect the penalty difference caused by transfer time on passengers’ perceived utility under various numbers of transfers. Next, based on the revealed preference data collected in the Guangzhou Metro, the proposed model is calibrated. The appropriate perceived transfer threshold value and the route choice preferences are analyzed. Finally, the model is applied to a personalized route planning case to demonstrate the engineering practicability of route choice behavior analysis. The results show that the introduction of the perceived transfer threshold is helpful to improve the model’s explanatory abilities. In addition, personalized route planning based on route choice preferences can meet passengers’ diversified travel demands. PMID:28957376

Robust LS-SVM-based adaptive constrained control for a class of uncertain nonlinear systems with time-varying predefined performance

Science.gov (United States)

Luo, Jianjun; Wei, Caisheng; Dai, Honghua; Yuan, Jianping

2018-03-01

This paper focuses on robust adaptive control for a class of uncertain nonlinear systems subject to input saturation and external disturbance with guaranteed predefined tracking performance. To reduce the limitations of classical predefined performance control method in the presence of unknown initial tracking errors, a novel predefined performance function with time-varying design parameters is first proposed. Then, aiming at reducing the complexity of nonlinear approximations, only two least-square-support-vector-machine-based (LS-SVM-based) approximators with two design parameters are required through norm form transformation of the original system. Further, a novel LS-SVM-based adaptive constrained control scheme is developed under the time-vary predefined performance using backstepping technique. Wherein, to avoid the tedious analysis and repeated differentiations of virtual control laws in the backstepping technique, a simple and robust finite-time-convergent differentiator is devised to only extract its first-order derivative at each step in the presence of external disturbance. In this sense, the inherent demerit of backstepping technique-;explosion of terms; brought by the recursive virtual controller design is conquered. Moreover, an auxiliary system is designed to compensate the control saturation. Finally, three groups of numerical simulations are employed to validate the effectiveness of the newly developed differentiator and the proposed adaptive constrained control scheme.

Quantum chemistry-assisted synthesis route development

International Nuclear Information System (INIS)

Hori, Kenji; Sumimoto, Michinori; Murafuji, Toshihiro

2015-01-01

We have been investigating “quantum chemistry-assisted synthesis route development” using in silico screenings and applied the method to several targets. Another example was conducted to develop synthesis routes for a urea derivative, namely 1-(4-(trifluoromethyl)-2-oxo-2H-chromen-7-yl)urea. While five synthesis routes were examined, only three routes passed the second in silico screening. Among them, the reaction of 7-amino-4-(trifluoromethyl)-2H-chromen-2-one and O-methyl carbamate with BF 3 as an additive was ranked as the first choice for synthetic work. We were able to experimentally obtain the target compound even though its yield was as low as 21 %. The theoretical result was thus consistent with that observed. The summary of transition state data base (TSDB) is also provided. TSDB is the key to reducing time of in silico screenings

A Space-Time Network-Based Modeling Framework for Dynamic Unmanned Aerial Vehicle Routing in Traffic Incident Monitoring Applications

Directory of Open Access Journals (Sweden)

Jisheng Zhang

2015-06-01

Full Text Available It is essential for transportation management centers to equip and manage a network of fixed and mobile sensors in order to quickly detect traffic incidents and further monitor the related impact areas, especially for high-impact accidents with dramatic traffic congestion propagation. As emerging small Unmanned Aerial Vehicles (UAVs start to have a more flexible regulation environment, it is critically important to fully explore the potential for of using UAVs for monitoring recurring and non-recurring traffic conditions and special events on transportation networks. This paper presents a space-time network- based modeling framework for integrated fixed and mobile sensor networks, in order to provide a rapid and systematic road traffic monitoring mechanism. By constructing a discretized space-time network to characterize not only the speed for UAVs but also the time-sensitive impact areas of traffic congestion, we formulate the problem as a linear integer programming model to minimize the detection delay cost and operational cost, subject to feasible flying route constraints. A Lagrangian relaxation solution framework is developed to decompose the original complex problem into a series of computationally efficient time-dependent and least cost path finding sub-problems. Several examples are used to demonstrate the results of proposed models in UAVs’ route planning for small and medium-scale networks.

Perancangan dan Analisis Redistribution Routing Protocol OSPF dan EIGRP

Directory of Open Access Journals (Sweden)

DWI ARYANTA

2016-02-01

Full Text Available Abstrak OSPF (Open Shortest Path First dan EIGRP (Enhanced Interior Gateway Routing Protocol adalah dua routing protokol yang banyak digunakan dalam jaringan komputer. Perbedaan karakteristik antar routing protokol menimbulkan masalah dalam pengiriman paket data. Teknik redistribution adalah solusi untuk melakukan komunikasi antar routing protokol. Dengan menggunakan software Cisco Packet Tracer 5.3 pada penelitian ini dibuat simulasi OSPF dan EIGRP yang dihubungkan oleh teknik redistribution, kemudian dibandingkan kualitasnya dengan single routing protokol EIGRP dan OSPF. Parameter pengujian dalam penelitian ini adalah nilai time delay dan trace route. Nilai trace route berdasarkan perhitungan langsung cost dan metric dibandingkan dengan hasil simulasi. Hasilnya dapat dilakukan proses redistribution OSPF dan EIGRP. Nilai delay redistribution lebih baik 1% dibanding OSPF dan 2-3% di bawah EIGRP tergantung kepadatan traffic. Dalam perhitungan trace route redistribution dilakukan 2 perhitungan, yaitu cost untuk area OSPF dan metric pada area EIGRP. Pengambilan jalur utama dan alternatif pengiriman paket berdasarkan nilai cost dan metric yang terkecil, hal ini terbukti berdasarkan perhitungan dan simulasi. Kata kunci: OSPF, EIGRP, Redistribution, Delay, Cost, Metric. Abstract OSPF (Open Shortest Path First and EIGRP (Enhanced Interior Gateway Routing Protocol are two routing protocols are widely used in computer networks. Differences between the characteristics of routing protocols pose a problem in the delivery of data packets. Redistribution technique is the solution for communication between routing protocols. By using the software Cisco Packet Tracer 5.3 in this study were made simulating OSPF and EIGRP redistribution linked by technique, then compared its quality with a single EIGRP and OSPF routing protocols. Testing parameters in this study is the value of the time delay and trace route. Value trace route based on direct calculation of cost

A System Concept for Facilitating User Preferences in En Route Airspace

Science.gov (United States)

Vivona, R. A.; Ballin, M. G.; Green, S. M.; Bach, R. E.; McNally, B. D.

1996-01-01

The Federal Aviation Administration is trying to make its air traffic management system more responsive to the needs of the aviation community by exploring the concept of 'free flight' for aircraft flying under instrument flight rules. A logical first step toward free flight could be made without significantly altering current air traffic control (ATC) procedures or requiring new airborne equipment by designing a ground-based system to be highly responsive to 'user preference' in en route airspace while providing for an orderly transition to the terminal area. To facilitate user preference in all en route environments, a system based on an extension of the Center/TRACON Automation System (CTAS) is proposed in this document. The new system would consist of two integrated components. An airspace tool (AT) focuses on unconstrained en route aircraft (e.g., not transitioning to the terminal airspace), taking advantage of the relatively unconstrained nature of their flights and using long-range trajectory prediction to provide cost-effective conflict resolution advisories to sector controllers. A sector tool (ST) generates efficient advisories for all aircraft, with a focus on supporting controllers in analyzing and resolving complex, highly constrained traffic situations. When combined, the integrated AT/ST system supports user preference in any air route traffic control center sector. The system should also be useful in evaluating advanced free-flight concepts by serving as a test bed for future research. This document provides an overview of the design concept, explains its anticipated benefits, and recommends a development strategy that leads to a deployable system.

Improving the Dominating-Set Routing over Delay-Tolerant Mobile Ad-Hoc Networks via Estimating Node Intermeeting Times

Directory of Open Access Journals (Sweden)

Preiss Bruno

2011-01-01

Full Text Available With limited coverage of wireless networks and frequent roaming of mobile users, providing a seamless communication service poses a technical challenge. In our previous research, we presented a supernode system architecture that employs the delay-tolerant network (DTN concept to provide seamless communications for roaming users over interconnected heterogeneous wireless networks. Mobile ad hoc networks (MANETs are considered a key component of the supernode system for services over an area not covered by other wireless networks. Within the super node system, a dominating-set routing technique is proposed to improve message delivery over MANETs and to achieve better resource utilization. The performance of the dominating-set routing technique depends on estimation accuracy of the probability of a future contact between nodes. This paper studies how node mobility can be modeled and used to better estimate the probability of a contact. We derive a distribution for the node-to-node intermeeting time and present numerical results to demonstrate that the distribution can be used to improve the dominating-set routing technique performance. Moreover, we investigate how the distribution can be employed to relax the constraints of selecting the dominating-set members in order to improve the system resource utilization.

Routing architecture and security for airborne networks

Science.gov (United States)

Deng, Hongmei; Xie, Peng; Li, Jason; Xu, Roger; Levy, Renato

2009-05-01

Airborne networks are envisioned to provide interconnectivity for terrestial and space networks by interconnecting highly mobile airborne platforms. A number of military applications are expected to be used by the operator, and all these applications require proper routing security support to establish correct route between communicating platforms in a timely manner. As airborne networks somewhat different from traditional wired and wireless networks (e.g., Internet, LAN, WLAN, MANET, etc), security aspects valid in these networks are not fully applicable to airborne networks. Designing an efficient security scheme to protect airborne networks is confronted with new requirements. In this paper, we first identify a candidate routing architecture, which works as an underlying structure for our proposed security scheme. And then we investigate the vulnerabilities and attack models against routing protocols in airborne networks. Based on these studies, we propose an integrated security solution to address routing security issues in airborne networks.

How Uncertain Information on Service Capacity Influences the Intermodal Routing Decision: A Fuzzy Programming Perspective

Directory of Open Access Journals (Sweden)

Yan Sun

2018-01-01

Full Text Available Capacity uncertainty is a common issue in the transportation planning field. However, few studies discuss the intermodal routing problem with service capacity uncertainty. Based on our previous study on the intermodal routing under deterministic capacity consideration, we systematically explore how service capacity uncertainty influences the intermodal routing decision. First of all, we adopt trapezoidal fuzzy numbers to describe the uncertain information of the service capacity, and further transform the deterministic capacity constraint into a fuzzy chance constraint based on fuzzy credibility measure. We then integrate such fuzzy chance constraint into the mixed-integer linear programming (MILP model proposed in our previous study to develop a fuzzy chance-constrained programming model. To enable the improved model to be effectively programmed in the standard mathematical programming software and solved by exact solution algorithms, a crisp equivalent linear reformulation of the fuzzy chance constraint is generated. Finally, we modify the empirical case presented in our previous study by replacing the deterministic service capacities with trapezoidal fuzzy ones. Using the modified empirical case, we utilize sensitivity analysis and fuzzy simulation to analyze the influence of service capacity uncertainty on the intermodal routing decision, and summarize some interesting insights that are helpful for decision makers.

A set packing inspired method for real-time junction train routing

DEFF Research Database (Denmark)

Lusby, Richard Martin; Larsen, Jesper; Ehrgott, Matthias

2013-01-01

Efficiently coordinating the often large number of interdependent, timetabled train movements on a railway junction, while satisfying a number of operational requirements, is one of the most important problems faced by a railway company. The most critical variant of the problem arises on a daily...... basis at major railway junctions where disruptions to rail traffic make the planned schedule/routing infeasible and rolling stock planners are forced to re-schedule/re-route trains in order to recover feasibility. The dynamic nature of the problem means that good solutions must be obtained quickly....... In this paper we describe a set packing inspired formulation of this problem and develop a branch-and-price based solution approach. A real life test instance arising in Germany and supplied by the major German railway company, Deutsche Bahn, indicates the efficiency of the proposed approach by confirming...

A Set Packing Inspired Method for Real-Time Junction Train Routing

DEFF Research Database (Denmark)

Lusby, Richard Martin; Larsen, Jesper; Ehrgott, Matthias

Efficiently coordinating the often large number of interdependent, timetabled train movements on a railway junction, while satisfying a number of operational requirements, is one of the most important problems faced by a railway company. The most critical variant of the problem arises on a daily...... basis at major railway junctions where disruptions to rail traffi c make the planned schedule/routing infeasible and rolling stock planners are forced to reschedule/re-route trains in order to recover feasibility. The dynamic nature of the problem means that good solutions must be obtained quickly....... In this paper we describe a set packing inspired formulation of this problem and develop a branch-and-price based solution approach. A real life test instance arising in Germany and supplied by the major German railway company, Deutsche Bahn, indicates the efficiency of the proposed approach by confirming...

Evolutionary constrained optimization

CERN Document Server

Deb, Kalyanmoy

2015-01-01

This book makes available a self-contained collection of modern research addressing the general constrained optimization problems using evolutionary algorithms. Broadly the topics covered include constraint handling for single and multi-objective optimizations; penalty function based methodology; multi-objective based methodology; new constraint handling mechanism; hybrid methodology; scaling issues in constrained optimization; design of scalable test problems; parameter adaptation in constrained optimization; handling of integer, discrete and mix variables in addition to continuous variables; application of constraint handling techniques to real-world problems; and constrained optimization in dynamic environment. There is also a separate chapter on hybrid optimization, which is gaining lots of popularity nowadays due to its capability of bridging the gap between evolutionary and classical optimization. The material in the book is useful to researchers, novice, and experts alike. The book will also be useful...

Constrained Sintering in Fabrication of Solid Oxide Fuel Cells.

Science.gov (United States)

Lee, Hae-Weon; Park, Mansoo; Hong, Jongsup; Kim, Hyoungchul; Yoon, Kyung Joong; Son, Ji-Won; Lee, Jong-Ho; Kim, Byung-Kook

2016-08-09

Solid oxide fuel cells (SOFCs) are inevitably affected by the tensile stress field imposed by the rigid substrate during constrained sintering, which strongly affects microstructural evolution and flaw generation in the fabrication process and subsequent operation. In the case of sintering a composite cathode, one component acts as a continuous matrix phase while the other acts as a dispersed phase depending upon the initial composition and packing structure. The clustering of dispersed particles in the matrix has significant effects on the final microstructure, and strong rigidity of the clusters covering the entire cathode volume is desirable to obtain stable pore structure. The local constraints developed around the dispersed particles and their clusters effectively suppress generation of major process flaws, and microstructural features such as triple phase boundary and porosity could be readily controlled by adjusting the content and size of the dispersed particles. However, in the fabrication of the dense electrolyte layer via the chemical solution deposition route using slow-sintering nanoparticles dispersed in a sol matrix, the rigidity of the cluster should be minimized for the fine matrix to continuously densify, and special care should be taken in selecting the size of the dispersed particles to optimize the thermodynamic stability criteria of the grain size and film thickness. The principles of constrained sintering presented in this paper could be used as basic guidelines for realizing the ideal microstructure of SOFCs.

State alternative route designations

International Nuclear Information System (INIS)

1989-07-01

Pursuant to the Hazardous Materials Transportation Act (HMTA), the Department of Transportation (DOT) has promulgated a comprehensive set of regulations regarding the highway transportation of high-level radioactive materials. These regulations, under HM-164 and HM-164A, establish interstate highways as the preferred routes for the transportation of radioactive materials within and through the states. The regulations also provide a methodology by which a state may select alternative routes. First,the state must establish a ''state routing agency,'' defined as an entity authorized to use the state legal process to impose routing requirements on carriers of radioactive material (49 CFR 171.8). Once identified, the state routing agency must select routes in accordance with Large Quantity Shipments of Radioactive Materials or an equivalent routing analysis. Adjoining states and localities should be consulted on the impact of proposed alternative routes as a prerequisite of final route selection. Lastly, the states must provide written notice of DOT of any alternative route designation before the routes are deemed effective

Terrestrial Sagnac delay constraining modified gravity models

Science.gov (United States)

Karimov, R. Kh.; Izmailov, R. N.; Potapov, A. A.; Nandi, K. K.

2018-04-01

Modified gravity theories include f(R)-gravity models that are usually constrained by the cosmological evolutionary scenario. However, it has been recently shown that they can also be constrained by the signatures of accretion disk around constant Ricci curvature Kerr-f(R0) stellar sized black holes. Our aim here is to use another experimental fact, viz., the terrestrial Sagnac delay to constrain the parameters of specific f(R)-gravity prescriptions. We shall assume that a Kerr-f(R0) solution asymptotically describes Earth's weak gravity near its surface. In this spacetime, we shall study oppositely directed light beams from source/observer moving on non-geodesic and geodesic circular trajectories and calculate the time gap, when the beams re-unite. We obtain the exact time gap called Sagnac delay in both cases and expand it to show how the flat space value is corrected by the Ricci curvature, the mass and the spin of the gravitating source. Under the assumption that the magnitude of corrections are of the order of residual uncertainties in the delay measurement, we derive the allowed intervals for Ricci curvature. We conclude that the terrestrial Sagnac delay can be used to constrain the parameters of specific f(R) prescriptions. Despite using the weak field gravity near Earth's surface, it turns out that the model parameter ranges still remain the same as those obtained from the strong field accretion disk phenomenon.

Multicriteria vehicle routing problem solved by artificial immune system

Directory of Open Access Journals (Sweden)

Bogna MRÓWCZYŃSKA

2015-09-01

Full Text Available Vehicles route planning in large transportation companies, where drivers are workers, usually takes place on the basis of experience or intuition of the employees. Because of the cost and environmental protection, it is important to save fuel, thus planning routes in an optimal way. In this article an example of the problem is presented solving delivery vans route planning taking into account the distance and travel time within the constraints of vehicle capacities, restrictions on working time of drivers and having varying degrees of movement. An artificial immune system was used for the calculations.

Lessons learned by southern states in designating alternative routes

International Nuclear Information System (INIS)

1989-08-01

The purpose of this report is to discuss the ''lessons learned'' by the five states within the southem region that have designated alternative or preferred routes under the regulations of the Department of Transportation (DOT) established for the transportation of radioactive materials. The document was prepared by reviewing applicable federal laws and regulations, examining state reports and documents and contacting state officials and routing agencies involved in making routing decisions. In undertaking this project, the Southern States Energy Board hopes to reveal the process used by states that have designated alternative routes and thereby share their experiences (i.e., lessons learned) with other southern states that have yet to make designations. Under DOT regulations (49 CFR 177.826), carriers of highway route controlled quantities of radioactive materials (which include spent nuclear fuel and high-level waste) must use preferred routes selected to reduce time in transit. Such preferred routes consist of (1) an interstate system highway with use of an interstate system bypass or beltway around cities when available, and (2) alternate routes selected by a ''state routing agency.''

Rich Vehicle Routing Problems and Applications

DEFF Research Database (Denmark)

Wen, Min

very short computational time on real-life data involving up to 200 pairs of suppliers and customers. The second problem we consider is a dynamic vehicle routing problem with multiple objectives over a planning horizon that consists of multiple periods. In this problem, customer orders are revealed...... the company’s solution in terms of all the objectives, including the travel time, customer waiting and daily workload balances, under the given constraints considered in the work. Finally, we address an integrated vehicle routing and driver scheduling problem, in which a large number of practical constraints....... The method is implemented and tested on real-life data involving up to 2000 orders. It is shown that the method is able to provide solutions of good quality within reasonable running time....

Hurricane Evacuation Routes

Data.gov (United States)

Department of Homeland Security — Hurricane Evacuation Routes in the United States A hurricane evacuation route is a designated route used to direct traffic inland in case of a hurricane threat. This...

Satellite network robust QoS-aware routing

CERN Document Server

Long, Fei

2014-01-01

Satellite Network Robust QoS-aware Routing presents a novel routing strategy for satellite networks. This strategy is useful for the design of multi-layered satellite networks as it can greatly reduce the number of time slots in one system cycle. The traffic prediction and engineering approaches make the system robust so that the traffic spikes can be handled effectively. The multi-QoS optimization routing algorithm can satisfy various potential user requirements. Clear and sufficient illustrations are also presented in the book. As the chapters cover the above topics independently, readers from different research backgrounds in constellation design, multi-QoS routing, and traffic engineering can benefit from the book.   Fei Long is a senior engineer at Beijing R&D Center of 54th Research Institute of China Electronics Technology Group Corporation.

Subset-row inequalities applied to the vehicle routing problem with time windows

DEFF Research Database (Denmark)

Jepsen, Mads Kehlet; Petersen, Bjørn; Spoorendonk, Simon

2008-01-01

constraints as the pricing problem. We introduce the subset-row inequalities, which are Chvatal-Gomory rank-1 cuts based on a subset of the constraints in the master problem. Applying a subset-row inequality in the master problem increases the complexity of the label-setting algorithm used to solve......This paper presents a branch-and-cut-and-price algorithm for the vehicle-routing problem with time windows. The standard Dantzig-Wolfe decomposition of the arc flow formulation leads to a set-partitioning problem as the master problem and an elementary shortest-path problem with resource...... the pricing problem because an additional resource is added for each inequality. We propose a modified dominance criterion that makes it possible to dominate more labels by exploiting the step-like structure of the objective function of the pricing problem. Computational experiments have been performed...

Radon exposure in selected underground touring routes in Poland

International Nuclear Information System (INIS)

Olszewski, J.; Chruscielewski, W.; Jankowski, J.

2006-01-01

The radioactive elements abounding in the natural environment cause that the whole human population is exposed to radiation. In Poland, mean gamma radiation dose power is 45.4 n Gy h -1 , while atmospheric radon concentration is 4.4 Bq m -3 [1]. In closed rooms, where radon tends to accumulate, the concentrations may be many times higher.Underground touring routes located in caves, mines, ancient cellars, vaults may accumulate radon at concentrations several thousand times exceeding its atmospheric levels. Studies on natural radioactivity in underground touring routes, with particular reference to caves, have continued worldwide since the 80's. Current register of underground touring routes in Poland comprises over 30 items, which include caves (e.g. Niedzwiedzia), mines (Wieliczka), cellars and underground stores (Opatow City vaults) and military objects (underground factories of Walim). The Nofer Institute of Occupational Medicine has for several years already continued determinations of periodical mean radon concentrations in four underground touring routes (starting date in parentheses): Niedzwiedzia Cave (1995); Kowary Drifts closed uranium mine (2001); closed uranium mine in Kletno (2004); Zloty Stok closed gold mine (2004); Osowka underground city in Gluszyca (2004).The results of our determinations of radon concentrations at five selected touring routes lead to the following conclusions. 1. The exposure in the Kowary Drifts touring route is at the level of 5% of the recommended maximum annual admissible limit of 20 mSv. 2. It is assessed that workers of the touring routes where exposures are estimated from the measured concentrations and the time spent underground may receive doses ranging from 0.01 to 5 mSv. (N.C.)

Radon exposure in selected underground touring routes in Poland

Energy Technology Data Exchange (ETDEWEB)

Olszewski, J.; Chruscielewski, W.; Jankowski, J. [Nofer Institute of Occupational Medicine, Dept. of Radiation Protection, Lodz (Poland)

2006-07-01

The radioactive elements abounding in the natural environment cause that the whole human population is exposed to radiation. In Poland, mean gamma radiation dose power is 45.4 n Gy h{sup -1}, while atmospheric radon concentration is 4.4 Bq m{sup -3} [1]. In closed rooms, where radon tends to accumulate, the concentrations may be many times higher.Underground touring routes located in caves, mines, ancient cellars, vaults may accumulate radon at concentrations several thousand times exceeding its atmospheric levels. Studies on natural radioactivity in underground touring routes, with particular reference to caves, have continued worldwide since the 80's. Current register of underground touring routes in Poland comprises over 30 items, which include caves (e.g. Niedzwiedzia), mines (Wieliczka), cellars and underground stores (Opatow City vaults) and military objects (underground factories of Walim). The Nofer Institute of Occupational Medicine has for several years already continued determinations of periodical mean radon concentrations in four underground touring routes (starting date in parentheses): Niedzwiedzia Cave (1995); Kowary Drifts closed uranium mine (2001); closed uranium mine in Kletno (2004); Zloty Stok closed gold mine (2004); Osowka underground city in Gluszyca (2004).The results of our determinations of radon concentrations at five selected touring routes lead to the following conclusions. 1. The exposure in the Kowary Drifts touring route is at the level of 5% of the recommended maximum annual admissible limit of 20 mSv. 2. It is assessed that workers of the touring routes where exposures are estimated from the measured concentrations and the time spent underground may receive doses ranging from 0.01 to 5 mSv. (N.C.)

Solving a bi-objective mathematical model for location-routing problem with time windows in multi-echelon reverse logistics using metaheuristic procedure

Science.gov (United States)

Ghezavati, V. R.; Beigi, M.

2016-12-01

During the last decade, the stringent pressures from environmental and social requirements have spurred an interest in designing a reverse logistics (RL) network. The success of a logistics system may depend on the decisions of the facilities locations and vehicle routings. The location-routing problem (LRP) simultaneously locates the facilities and designs the travel routes for vehicles among established facilities and existing demand points. In this paper, the location-routing problem with time window (LRPTW) and homogeneous fleet type and designing a multi-echelon, and capacitated reverse logistics network, are considered which may arise in many real-life situations in logistics management. Our proposed RL network consists of hybrid collection/inspection centers, recovery centers and disposal centers. Here, we present a new bi-objective mathematical programming (BOMP) for LRPTW in reverse logistic. Since this type of problem is NP-hard, the non-dominated sorting genetic algorithm II (NSGA-II) is proposed to obtain the Pareto frontier for the given problem. Several numerical examples are presented to illustrate the effectiveness of the proposed model and algorithm. Also, the present work is an effort to effectively implement the ɛ-constraint method in GAMS software for producing the Pareto-optimal solutions in a BOMP. The results of the proposed algorithm have been compared with the ɛ-constraint method. The computational results show that the ɛ-constraint method is able to solve small-size instances to optimality within reasonable computing times, and for medium-to-large-sized problems, the proposed NSGA-II works better than the ɛ-constraint.

Pseudo-Cycle-Based Multicast Routing in Wormhole-Routed Networks

Institute of Scientific and Technical Information of China (English)

SONG JianPing (宋建平); HOU ZiFeng (侯紫峰); XU Ming (许铭)

2003-01-01

This paper addresses the problem of fault-tolerant multicast routing in wormholerouted multicomputers. A new pseudo-cycle-based routing method is presented for constructing deadlock-free multicast routing algorithms. With at most two virtual channels this technique can be applied to any connected networks with arbitrary topologies. Simulation results show that this technique results in negligible performance degradation even in the presence of a large number of faulty nodes.

Routing in opportunistic networks

CERN Document Server

Dhurandher, Sanjay; Anpalagan, Alagan; Vasilakos, Athanasios

2013-01-01

This book provides a comprehensive guide to selected topics, both ongoing and emerging, in routing in OppNets. The book is edited by worldwide technical leaders, prolific researchers and outstanding academics, Dr. Isaac Woungang and co-editors, Dr. Sanjay Kumar Dhurandher, Prof. Alagan Anpalagan and Prof. Athanasios Vasilakos. Consisting of contributions from well known and high profile researchers and scientists in their respective specialties, the main topics that are covered in this book include mobility and routing, social-aware routing, context-based routing, energy-aware routing, incentive-aware routing, stochastic routing, modeling of intermittent connectivity, in both infrastructure and infrastructure-less OppNets. Key Features: Discusses existing and emerging techniques for routing in infrastructure and infrastructure-less OppNets. Provides a unified covering of otherwise disperse selected topics on routing in infrastructure and infrastructure-less OppNets.  Includes a set of PowerPoint slides and g...

Reversible patterning of spherical shells through constrained buckling

Science.gov (United States)

Marthelot, J.; Brun, P.-T.; Jiménez, F. López; Reis, P. M.

2017-07-01

Recent advances in active soft structures envision the large deformations resulting from mechanical instabilities as routes for functional shape morphing. Numerous such examples exist for filamentary and plate systems. However, examples with double-curved shells are rarer, with progress hampered by challenges in fabrication and the complexities involved in analyzing their underlying geometrical nonlinearities. We show that on-demand patterning of hemispherical shells can be achieved through constrained buckling. Their postbuckling response is stabilized by an inner rigid mandrel. Through a combination of experiments, simulations, and scaling analyses, our investigation focuses on the nucleation and evolution of the buckling patterns into a reticulated network of sharp ridges. The geometry of the system, namely, the shell radius and the gap between the shell and the mandrel, is found to be the primary ingredient to set the surface morphology. This prominence of geometry suggests a robust, scalable, and tunable mechanism for reversible shape morphing of elastic shells.

An advanced traveler navigation system adapted to route choice preferences of the individual users

Directory of Open Access Journals (Sweden)

Mahyar Amirgholy

2017-12-01

Full Text Available The majority of existing navigation systems only account for a single aspect of the route choice, like travel time or distance, in finding the optimal route for the trips in the network. In this research, we first identify a range of diverse factors that travelers take into account in their route choice decision in the network. A stated preference survey is conducted to show the heterogeneity in the preferences of users and its dependence to the purpose of the trips over the weekdays and weekends. Interestingly, results of the survey show that road safety is the most influential factor in the route choice decision of the average participants over weekends, exceeding even the travel time, and participants give more importance to the scenic quality of the routes for their weekend trips in comparison to their weekday trips. The results of the second part of the survey also indicate that in 27% of the cases participants choose routes other than the ones suggested by navigation systems, and 33% of the times that they take the suggested routes, they modify these routes according to their own preferences. The partial inability of existing navigation systems to suggest the routes that match the preferences of users can be attributed to ignoring (1 the diversity in influential factors and (2 the heterogeneity in preferences of the users by these systems. We propose a dynamic mixed logit route choice model to include the effects of information and learning to estimate parameters of a multivariable utility function for individual users based on their own historical route choice data over time. Finally, we present the concept of a smart navigation system that can gather the required information from real-time and online sources to suggest the routes that best match the users’ own preferences.

Integrating routing decisions in public transportation problems

CERN Document Server

Schmidt, Marie E

2014-01-01

This book treats three planning problems arising in public railway transportation planning: line planning, timetabling, and delay management, with the objective to minimize passengers’ travel time. While many optimization approaches simplify these problems by assuming that passengers’ route choice is independent of the solution, this book focuses on models which take into account that passengers will adapt their travel route to the implemented planning solution. That is, a planning solution and passengers’ routes are determined and evaluated simultaneously. This work is technically deep, with insightful findings regarding complexity and algorithmic approaches to public transportation problems with integrated passenger routing. It is intended for researchers in the fields of mathematics, computer science, or operations research, working in the field of public transportation from an optimization standpoint. It is also ideal for students who want to gain intuition and experience in doing complexity proofs ...

Magnetic exchange couplings from constrained density functional theory: an efficient approach utilizing analytic derivatives.

Science.gov (United States)

Phillips, Jordan J; Peralta, Juan E

2011-11-14

We introduce a method for evaluating magnetic exchange couplings based on the constrained density functional theory (C-DFT) approach of Rudra, Wu, and Van Voorhis [J. Chem. Phys. 124, 024103 (2006)]. Our method shares the same physical principles as C-DFT but makes use of the fact that the electronic energy changes quadratically and bilinearly with respect to the constraints in the range of interest. This allows us to use coupled perturbed Kohn-Sham spin density functional theory to determine approximately the corrections to the energy of the different spin configurations and construct a priori the relevant energy-landscapes obtained by constrained spin density functional theory. We assess this methodology in a set of binuclear transition-metal complexes and show that it reproduces very closely the results of C-DFT. This demonstrates a proof-of-concept for this method as a potential tool for studying a number of other molecular phenomena. Additionally, routes to improving upon the limitations of this method are discussed. © 2011 American Institute of Physics

The Effect of Trail Pheromone and Path Confinement on Learning of Complex Routes in the Ant Lasius niger.

Science.gov (United States)

Czaczkes, Tomer J; Weichselgartner, Tobias; Bernadou, Abel; Heinze, Jürgen

2016-01-01

Route learning is key to the survival of many central place foragers, such as bees and many ants. For ants which lay pheromone trails, the presence of a trail may act as an important source of information about whether an error has been made. The presence of trail pheromone has been demonstrated to support route learning, and the effect of pheromones on route choice have been reported to persist even after the pheromones have been removed. This could be explained in two ways: the pheromone may constrain the ants onto the correct route, thus preventing errors and aiding learning. Alternatively, the pheromones may act as a 'reassurance', signalling that the learner is on the right path and that learning the path is worthwhile. Here, we disentangle pheromone presence from route confinement in order to test these hypotheses, using the ant Lasius niger as a model. Unexpectedly, we did not find any evidence that pheromones support route learning. Indeed, there was no evidence that ants confined to the correct route learned at all. Thus, while we cannot support the 'reassurance' hypothesis, we can rule out the 'confinement' hypothesis. Other findings, such as a reduction in pheromone deposition in the presence of trail pheromones, are remarkably consistent with previous experiments. As previously reported, ants which make errors on their outward journey upregulate pheromone deposition on their return. Surprisingly, ants which would go on to make an error down-regulate pheromone deposition on their outward journey, hinting at a capacity for ants to gauge the quality of their own memories.

The Effect of Trail Pheromone and Path Confinement on Learning of Complex Routes in the Ant Lasius niger.

Directory of Open Access Journals (Sweden)

Tomer J Czaczkes

Full Text Available Route learning is key to the survival of many central place foragers, such as bees and many ants. For ants which lay pheromone trails, the presence of a trail may act as an important source of information about whether an error has been made. The presence of trail pheromone has been demonstrated to support route learning, and the effect of pheromones on route choice have been reported to persist even after the pheromones have been removed. This could be explained in two ways: the pheromone may constrain the ants onto the correct route, thus preventing errors and aiding learning. Alternatively, the pheromones may act as a 'reassurance', signalling that the learner is on the right path and that learning the path is worthwhile. Here, we disentangle pheromone presence from route confinement in order to test these hypotheses, using the ant Lasius niger as a model. Unexpectedly, we did not find any evidence that pheromones support route learning. Indeed, there was no evidence that ants confined to the correct route learned at all. Thus, while we cannot support the 'reassurance' hypothesis, we can rule out the 'confinement' hypothesis. Other findings, such as a reduction in pheromone deposition in the presence of trail pheromones, are remarkably consistent with previous experiments. As previously reported, ants which make errors on their outward journey upregulate pheromone deposition on their return. Surprisingly, ants which would go on to make an error down-regulate pheromone deposition on their outward journey, hinting at a capacity for ants to gauge the quality of their own memories.

Planning routes around the world: International evidence for southern route preferences

NARCIS (Netherlands)

Brunyé, Tad T.; Andonova, Elena; Meneghetti, Chiara; Noordzij, Matthijs Leendert; Pazzaglia, Francesca; Wienemann, Rasmus; Mahoney, Caroline R.; Taylor, Holly A.

2012-01-01

Three studies test whether the southern route preference, which describes the tendency for route planners to disproportionately select south- rather than north-going routes, can be attributed to regional elevation patterns; specifically, we ask whether this effect replicates in three topographically

Installation of dynamic travel time signs and efforts to obtain and test a graphical route information panel (GRIP) sign in Austin.

Science.gov (United States)

2016-08-01

Graphic Route Information Panel (GRIP) signs use a combination of text, colors, and representative maps of : the roadway system to convey real-time roadway congestion location and severity information. The intent of : this project was to facilitate t...

Indoor Semantic Modelling for Routing: The Two-Level Routing Approach for Indoor Navigation

Directory of Open Access Journals (Sweden)

Liu Liu

2017-11-01

detailed levels. • On the conceptual level, it supports routing on a logical network and assists the derivation of a conceptual path (i.e., logical path for a user in terms of space sequence. Routing criteria are designed based on the INSM semantics of spaces, which can generate logical paths similar to human wayfinding results such as minimizing VerticalUnit or HorizontalConnector. • On the detailed level, it considers the size of users and results in obstacle-avoiding paths. By using this approach, geometric networks can be generated to avoid obstacles for the given users and accessible paths are flexibly provided for user demands. This approach can process changes of user size more efficiently, in contrast to routing on a complete geometric network. • It supports routing on both the logical and the geometric networks, which can generate geometric paths based on user-specific logical paths, or re-compute logical paths when geometric paths are inaccessible. This computation method is very useful for complex buildings. The two-level routing approach can flexibly provide logical and geometric paths according to user preferences and sizes, and can adjust the generated paths in limited time. Based on the two-level routing approach, this thesis also provides a vision on possible cooperation with other methods. A potential direction is to design more routing options according to other indoor scenarios and user preferences. Extensions of the two-level routing approach, such as other types of semantics, multi-level networks and dynamic obstacles, will make it possible to deal with other routing cases. Last but not least, it is also promising to explore its relationships with indoor guidance, different building subdivisions and outdoor navigation.

’Football Fitness’: Constraining and enabling possibilities for the management of leisure time for middle aged women

DEFF Research Database (Denmark)

Thing, Lone Friis; Hybholt, Maria Gliemann; Ottesen, Laila

recreational football activities and the ‘Football Fitness’ concept are experienced from a participant perspective is examined. We investigate how the implementation is actually carried out in the local football clubs and identify constraining and enabling possibilities for the management of leisure time. We......The aim of the paper is to generate empirically based sociological knowledge about a ‘Football Fitness’ intervention carried out in associative sport clubs. There is an increased pressure on the voluntary sector, e.g. the sport clubs, to embrace new segments of users and to meet social and health......, and inspired by them, we have chosen to analyse Football Fitness as part of a spare-time spectrum. How do grown up women make sense of their new ‘football lives’?...

Routing of Electric Vehicles: City Distribution in Copenhagen

DEFF Research Database (Denmark)

Linde, Esben; Larsen, Allan; Nørrelund, Anders Vedsted

In this work, a Vehicle Routing Problem with Time Windows considering EV constraints of limited driving range and freight capacity is addressed (EVRPTW). The EVs are allowed to recharge at certain locations, and aspects of intelligent location of these recharging points are considered....... The objective is to find the least cost plan for EV routing and compare this to conventional routing. A heuristic method is developed and tested on data based on real-life collected data on distribution vehicles in central Copenhagen, Denmark. The EVRPTW has so far received little attention in the literature...

Route activity tracking and management using available technology

Directory of Open Access Journals (Sweden)

Sam Yousef Khoury

2012-01-01

Full Text Available Small organizations that maintain their own fleet and make their own deliveries are responsible for ensuring their drivers are utilizing the most efficient routes while delivering products to their customers. Furthermore, efficient delivery requires that drivers spend as little time as possible dropping off and picking up products, since these activities are referred to as “non-value added activities,” although they are necessary tasks in the order cycle process. To aid in reducing order cycle times, large organizations that can afford it have employed transportation management systems. Unfortunately, small organizations with limited resources are less likely to adopt transportation management systems, despite the need for such automation. One solution is to use available productivity software to track and manage driver route activity in an effort to improve and maintain driver productivity by reducing non-value time and identifying optimal routes. This paper will outline how office productivity software such as Microsoft® Access can meet the needs of small organizations with limited resources by describing the development and use of a route activity database that employs an easy-to-use multi-user interface. This paper also includes the details of the underlying infrastructure and the user interface.

Application of cloud computing in power routing for clusters of microgrids using oblivious network routing algorithm

DEFF Research Database (Denmark)

Amini, M. Hadi; Broojeni, Kianoosh G.; Dragicevic, Tomislav

2017-01-01

of microgrid while preventing congestion as well as minimizing the power loss. Then, we present a two-layer simulation platform which considers both communication layer and physical layer of the microgrids' cluster. In order to improve the security of communication network, we perform the computations...... regarding the oblivious power routing via a cloud-based network. The proposed framework can be used for further studies that deal with the real-time simulation of the clusters of microgrids. In order to validate the effectiveness of the proposed framework, we implement our proposed oblivious routing scheme...

Optimization for routing vehicles of seafood product transportation

Science.gov (United States)

Soenandi, I. A.; Juan, Y.; Budi, M.

2017-12-01

Recently, increasing usage of marine products is creating new challenges for businesses of marine products in terms of transportation that used to carry the marine products like seafood to the main warehouse. This can be a problem if the carrier fleet is limited, and there are time constraints in terms of the freshness of the marine product. There are many ways to solve this problem, including the optimization of routing vehicles. In this study, this strategy is to implement in the marine product business in Indonesia with such an expected arrangement of the company to optimize routing problem in transportation with time and capacity windows. Until now, the company has not used the scientific method to manage the routing of their vehicle from warehouse to the location of marine products source. This study will solve a stochastic Vehicle Routing Problems (VRP) with time and capacity windows by using the comparison of six methods and looking the best results for the optimization, in this situation the company could choose the best method, in accordance with the existing condition. In this research, we compared the optimization with another method such as branch and bound, dynamic programming and Ant Colony Optimization (ACO). Finally, we get the best result after running ACO algorithm with existing travel time data. With ACO algorithm was able to reduce vehicle travel time by 3189.65 minutes, which is about 23% less than existing and based on consideration of the constraints of time within 2 days (including rest time for the driver) using 28 tons capacity of truck and the companies need two units of vehicles for transportation.

Constrained Sintering in Fabrication of Solid Oxide Fuel Cells

Science.gov (United States)

Lee, Hae-Weon; Park, Mansoo; Hong, Jongsup; Kim, Hyoungchul; Yoon, Kyung Joong; Son, Ji-Won; Lee, Jong-Ho; Kim, Byung-Kook

2016-01-01

Solid oxide fuel cells (SOFCs) are inevitably affected by the tensile stress field imposed by the rigid substrate during constrained sintering, which strongly affects microstructural evolution and flaw generation in the fabrication process and subsequent operation. In the case of sintering a composite cathode, one component acts as a continuous matrix phase while the other acts as a dispersed phase depending upon the initial composition and packing structure. The clustering of dispersed particles in the matrix has significant effects on the final microstructure, and strong rigidity of the clusters covering the entire cathode volume is desirable to obtain stable pore structure. The local constraints developed around the dispersed particles and their clusters effectively suppress generation of major process flaws, and microstructural features such as triple phase boundary and porosity could be readily controlled by adjusting the content and size of the dispersed particles. However, in the fabrication of the dense electrolyte layer via the chemical solution deposition route using slow-sintering nanoparticles dispersed in a sol matrix, the rigidity of the cluster should be minimized for the fine matrix to continuously densify, and special care should be taken in selecting the size of the dispersed particles to optimize the thermodynamic stability criteria of the grain size and film thickness. The principles of constrained sintering presented in this paper could be used as basic guidelines for realizing the ideal microstructure of SOFCs. PMID:28773795

Perancangan dan Analisis Redistribution Routing Protocol OSPF dan EIGRP

Directory of Open Access Journals (Sweden)

DWI ARYANTA

2014-07-01

OSPF (Open Shortest Path First and EIGRP (Enhanced Interior Gateway Routing Protocol are two routing protocols are widely used in computer networks. Differences between the characteristics of routing protocols pose a problem in the delivery of data packets. Redistribution technique is the solution for communication between routing protocols. By using the software Cisco Packet Tracer 5.3 in this study were made simulating OSPF and EIGRP redistribution linked by technique, then compared its quality with a single EIGRP and OSPF routing protocols. Testing parameters in this study is the value of the time delay and trace route. Value trace route based on direct calculation of cost and metric compared with the simulation results. The result can be OSPF and EIGRP redistribution process. Value delay redistribution 1% better than OSPF and EIGRP 2-3% under traffic density dependent. In calculating the trace route redistribution is done 2 calculations, the cost for OSPF area and the area of the EIGRP metric. Making primary and alternate paths based on the packet delivery rate and the cost of the smallest metric, it is proved by calculation and simulation. Keywords: OSPF, EIGRP, Redistribution, Delay, Cost, Metric.

Metabolism of T-2 toxin in rats: Effects of dose, route, and time

International Nuclear Information System (INIS)

Pfeiffer, R.L.; Swanson, S.P.; Buck, W.B.

1988-01-01

Metabolic profiles of the excreta from rats following iv, oral, and dermal administration of tritium-labeled T-2 toxin at 0.15 and 0.60 mg/kg were determined. The major metabolites in urine were 3'-OH HT-2, T-2 tetraol, and unknown metabolite M5, whereas the major metabolites in feces were deepoxy T-2 tetraol, 3'-OH HT-2, and unknown metabolites M5, M7, and M9. The metabolite labeled M9 (major metabolite) was tentatively identified as deepoxy 3'-OH HT-2. There was no significant effect on metabolic profiles due to dose, but there was a variable effect associated with the route of administration. The increase over time of appreciable levels of deepoxy metabolites as a percentage of extracted radioactivity was both consistent and statistically significant

Economic Possibilities of Shipping though Northern Sea Route1

Directory of Open Access Journals (Sweden)

Sung-Woo Lee

2014-12-01

Full Text Available Global warming and climate change haves brought a new issue in the Arctic sea. Therefore, we can now explore new shipping routes through the Arctic Ocean instead of the existing commercial route. In particular, the Northern Sea Route (NSR is one of the feasible shipping routes and, has provided tremendous shipping benefits. If the NSR becomes commercialized, we will be able to save about 5,000 nautical miles in distance and sailing time. In this study, we will emphasize some of the important results on the possibility of commercializing the shipping route in the Arctic. The NSR may bring positive economic effects in terms of shipping distance and time. For example, when utilizing the NSR, the maximum cargo traffic between Asia and Europe is expected to be around 46 million TEU. However, we also need to consider an expensive passage fee that is currently imposed by Russia. In conclusion, we maintain our efforts to protect the environment in the Arctic, in terms of logistics, and we need to explore every possible avenue to bring possible economic benefits to the North Pacific countries.

Quasicanonical structure of optimal control in constrained discrete systems

Science.gov (United States)

Sieniutycz, S.

2003-06-01

This paper considers discrete processes governed by difference rather than differential equations for the state transformation. The basic question asked is if and when Hamiltonian canonical structures are possible in optimal discrete systems. Considering constrained discrete control, general optimization algorithms are derived that constitute suitable theoretical and computational tools when evaluating extremum properties of constrained physical models. The mathematical basis of the general theory is the Bellman method of dynamic programming (DP) and its extension in the form of the so-called Carathéodory-Boltyanski (CB) stage criterion which allows a variation of the terminal state that is otherwise fixed in the Bellman's method. Two relatively unknown, powerful optimization algorithms are obtained: an unconventional discrete formalism of optimization based on a Hamiltonian for multistage systems with unconstrained intervals of holdup time, and the time interval constrained extension of the formalism. These results are general; namely, one arrives at: the discrete canonical Hamilton equations, maximum principles, and (at the continuous limit of processes with free intervals of time) the classical Hamilton-Jacobi theory along with all basic results of variational calculus. Vast spectrum of applications of the theory is briefly discussed.

Analyzing multiday route choice behavior of commuters using GPS data

Directory of Open Access Journals (Sweden)

Wenyun Tang

2016-02-01

Full Text Available In this study, accurate global position system and geographic information system data were employed to reveal multiday routes people used and to study multiday route choice behavior for the same origin–destination trips, from home to work. A new way of thinking about route choice modeling is provided in this study. Travelers are classified into three kinds based on the deviation between actual routes and the shortest travel time paths. Based on the classification, a two-stage route choice process is proposed, in which the first step is to classify the travelers and the second one is to model route choice behavior. After analyzing the characteristics of different types of travelers, an artificial neural network was adopted to classify travelers and model route choice behavior. An empirical study using global position systems data collected in Minneapolis–St Paul metropolitan area was carried out. It finds that most travelers follow the same route during commute trips on successive days. And different types of travelers have a significant difference in route choice property. The modeling results indicate that neural network framework can classify travelers and model route choice well.

A Scalable Context-Aware Objective Function (SCAOF) of Routing Protocol for Agricultural Low-Power and Lossy Networks (RPAL).

Science.gov (United States)

Chen, Yibo; Chanet, Jean-Pierre; Hou, Kun-Mean; Shi, Hongling; de Sousa, Gil

2015-08-10

In recent years, IoT (Internet of Things) technologies have seen great advances, particularly, the IPv6 Routing Protocol for Low-power and Lossy Networks (RPL), which provides a powerful and flexible routing framework that can be applied in a variety of application scenarios. In this context, as an important role of IoT, Wireless Sensor Networks (WSNs) can utilize RPL to design efficient routing protocols for a specific application to increase the ubiquity of networks with resource-constrained WSN nodes that are low-cost and easy to deploy. In this article, our work starts with the description of Agricultural Low-power and Lossy Networks (A-LLNs) complying with the LLN framework, and to clarify the requirements of this application-oriented routing solution. After a brief review of existing optimization techniques for RPL, our contribution is dedicated to a Scalable Context-Aware Objective Function (SCAOF) that can adapt RPL to the environmental monitoring of A-LLNs, through combining energy-aware, reliability-aware, robustness-aware and resource-aware contexts according to the composite routing metrics approach. The correct behavior of this enhanced RPL version (RPAL) was verified by performance evaluations on both simulation and field tests. The obtained experimental results confirm that SCAOF can deliver the desired advantages on network lifetime extension, and high reliability and efficiency in different simulation scenarios and hardware testbeds.

A Scalable Context-Aware Objective Function (SCAOF of Routing Protocol for Agricultural Low-Power and Lossy Networks (RPAL

Directory of Open Access Journals (Sweden)

Yibo Chen

2015-08-01

Full Text Available In recent years, IoT (Internet of Things technologies have seen great advances, particularly, the IPv6 Routing Protocol for Low-power and Lossy Networks (RPL, which provides a powerful and flexible routing framework that can be applied in a variety of application scenarios. In this context, as an important role of IoT, Wireless Sensor Networks (WSNs can utilize RPL to design efficient routing protocols for a specific application to increase the ubiquity of networks with resource-constrained WSN nodes that are low-cost and easy to deploy. In this article, our work starts with the description of Agricultural Low-power and Lossy Networks (A-LLNs complying with the LLN framework, and to clarify the requirements of this application-oriented routing solution. After a brief review of existing optimization techniques for RPL, our contribution is dedicated to a Scalable Context-Aware Objective Function (SCAOF that can adapt RPL to the environmental monitoring of A-LLNs, through combining energy-aware, reliability-aware, robustness-aware and resource-aware contexts according to the composite routing metrics approach. The correct behavior of this enhanced RPL version (RPAL was verified by performance evaluations on both simulation and field tests. The obtained experimental results confirm that SCAOF can deliver the desired advantages on network lifetime extension, and high reliability and efficiency in different simulation scenarios and hardware testbeds.

Hyperbolicity and constrained evolution in linearized gravity

International Nuclear Information System (INIS)

Matzner, Richard A.

2005-01-01

Solving the 4-d Einstein equations as evolution in time requires solving equations of two types: the four elliptic initial data (constraint) equations, followed by the six second order evolution equations. Analytically the constraint equations remain solved under the action of the evolution, and one approach is to simply monitor them (unconstrained evolution). Since computational solution of differential equations introduces almost inevitable errors, it is clearly 'more correct' to introduce a scheme which actively maintains the constraints by solution (constrained evolution). This has shown promise in computational settings, but the analysis of the resulting mixed elliptic hyperbolic method has not been completely carried out. We present such an analysis for one method of constrained evolution, applied to a simple vacuum system, linearized gravitational waves. We begin with a study of the hyperbolicity of the unconstrained Einstein equations. (Because the study of hyperbolicity deals only with the highest derivative order in the equations, linearization loses no essential details.) We then give explicit analytical construction of the effect of initial data setting and constrained evolution for linearized gravitational waves. While this is clearly a toy model with regard to constrained evolution, certain interesting features are found which have relevance to the full nonlinear Einstein equations

Estimating the implicit component of visuomotor rotation learning by constraining movement preparation time.

Science.gov (United States)

Leow, Li-Ann; Gunn, Reece; Marinovic, Welber; Carroll, Timothy J

2017-08-01

When sensory feedback is perturbed, accurate movement is restored by a combination of implicit processes and deliberate reaiming to strategically compensate for errors. Here, we directly compare two methods used previously to dissociate implicit from explicit learning on a trial-by-trial basis: 1 ) asking participants to report the direction that they aim their movements, and contrasting this with the directions of the target and the movement that they actually produce, and 2 ) manipulating movement preparation time. By instructing participants to reaim without a sensory perturbation, we show that reaiming is possible even with the shortest possible preparation times, particularly when targets are narrowly distributed. Nonetheless, reaiming is effortful and comes at the cost of increased variability, so we tested whether constraining preparation time is sufficient to suppress strategic reaiming during adaptation to visuomotor rotation with a broad target distribution. The rate and extent of error reduction under preparation time constraints were similar to estimates of implicit learning obtained from self-report without time pressure, suggesting that participants chose not to apply a reaiming strategy to correct visual errors under time pressure. Surprisingly, participants who reported aiming directions showed less implicit learning according to an alternative measure, obtained during trials performed without visual feedback. This suggests that the process of reporting can affect the extent or persistence of implicit learning. The data extend existing evidence that restricting preparation time can suppress explicit reaiming and provide an estimate of implicit visuomotor rotation learning that does not require participants to report their aiming directions. NEW & NOTEWORTHY During sensorimotor adaptation, implicit error-driven learning can be isolated from explicit strategy-driven reaiming by subtracting self-reported aiming directions from movement directions, or

Transportation routing analysis geographic information system -- TRAGIS, a multimodal transportation routing tool

International Nuclear Information System (INIS)

Johnson, P.E.

1995-01-01

Over 15 years ago, Oak Ridge National Laboratory (ORNL) developed two transportation routing models: HIGHWAY, which predicts truck transportation routes, and INTERLINE, which predicts rail transportation routes. Subsequent modifications have been made to enhance each of these models. Some of these changes include population density information for routes, HM-164 routing regulations for highway route controlled quantities of radioactive materials (RAM) truck shipments, and inclusion of waterway routing into INTERLINE. The AIRPORT model, developed 2 years after the HIGHWAY and INTERLINE models, serves as an emergency response tool. This model identifies the nearest airports from a designated location. Currently, the AIRPORT model is inactive. The Transportation Management Division of the US Department of Energy held a Baseline Requirements Assessment Session on the HIGHWAY, INTERLINE, and AIRPORT models in April 1994 to bring together many users of these models and other experts in the transportation routing field to discuss these models and to decide on the capabilities that needed to be added. Of the many needs discussed, the primary one was to have the network databases within a geographic information system (GIS). As a result of the Baseline Requirements Session, the development of a new GIS model has been initiated. This paper will discuss the development of the new Transportation Routing Analysis GIS (TRAGIS) model at ORNL

VINE ROUTES IN BULGARIA

Directory of Open Access Journals (Sweden)

Lyuben Hristov

2015-03-01

Full Text Available The article deals with a scheme for the modern vine route in Bulgaria. Five basic vine routes and one international, between Bulgaria, Macedonia and Greece are defined. All routes consider characteristic varieties of grapes and kinds of vine products. Vine tourist products combined with visits of important natural and anthropological object are in the bases of the defined routes. The described routes are an important contribution to development of alternative tourist products in the country.

Robust against route failure using power proficient reliable routing in MANET

Directory of Open Access Journals (Sweden)

M. Malathi

2018-03-01

Full Text Available The aim of this paper was to propose a novel routing protocol for Mobile Adhoc Network communication which reduces the route failure during transmission. The proposed routing protocol uses 3 salient parameters to discover the path which ensure the reliable communication. The quality of the channel, link quality and energy level of the node are the major reasons for unintentional node failure in mobile Adhoc network. So the proposed routing protocol considers these three parameters to select the best forwarder node in the path. The reliable data communication is achieved by transmitting data via path selected by the proposed routing scheme has been proven using network simulator (NS2. Keywords: Channel quality, Link quality, Mobile Adhoc Network (MANET, Residual energy

On the multiple depots vehicle routing problem with heterogeneous fleet capacity and velocity

Science.gov (United States)

Hanum, F.; Hartono, A. P.; Bakhtiar, T.

2018-03-01

This current manuscript concerns with the optimization problem arising in a route determination of products distribution. The problem is formulated in the form of multiple depots and time windowed vehicle routing problem with heterogeneous capacity and velocity of fleet. Model includes a number of constraints such as route continuity, multiple depots availability and serving time in addition to generic constraints. In dealing with the unique feature of heterogeneous velocity, we generate a number of velocity profiles along the road segments, which then converted into traveling-time tables. An illustrative example of rice distribution among villages by bureau of logistics is provided. Exact approach is utilized to determine the optimal solution in term of vehicle routes and starting time of service.

Evolution Strategies in the Multipoint Connections Routing

Directory of Open Access Journals (Sweden)

L. Krulikovska

2010-09-01

Full Text Available Routing of multipoint connections plays an important role in final cost and quality of a found connection. New algorithms with better results are still searched. In this paper, a possibility of using the evolution strategies (ES for routing is presented. Quality of found connection is evaluated from the view of final cost and time spent on a searching procedure. First, parametrical analysis of results of the ES are discussed and compared with the Prim’s algorithm, which was chosen as a representative of the deterministic routing algorithms. Second, ways for improving the ES are suggested and implemented. The obtained results are reviewed. The main improvements are specified and discussed in conclusion.

Hazardous materials routing - risk management of mismanagement

International Nuclear Information System (INIS)

Glickman, T.S.

1988-01-01

Along with emergency planning and preparedness, the placement of restrictions on routing has become an increasingly popular device for managing the highway and rail risks of hazardous materials transportation. Federal studies conducted in 1985 indicate that at that time there were 513 different state and local restrictions on the routing of hazardous materials for these two modes of transportation, and that there were 136 state and local notification requirements, that is, restrictions that take the form of a statute or ordinance requiring advance warning or periodic reporting about hazardous materials shipments. Routing restrictions also take the form of prohibiting the use of road, a tunnel, or a bridge for a specified set of hazardous materials

Efficient Networks Communication Routing Using Swarm Intelligence

OpenAIRE

Koushal Kumar

2012-01-01

As demonstrated by natural biological swarm’s collective intelligence has an abundance of desirable properties for problem-solving like in network routing. The focus of this paper is in the applications of swarm based intelligence in information routing for communication networks. As we know networks are growing and adopting new platforms as new technologies comes. Also according to new demands and requirements networks topologies and its complexity is increasing with time. Thus it is becomin...

Free and constrained symplectic integrators for numerical general relativity

International Nuclear Information System (INIS)

Richter, Ronny; Lubich, Christian

2008-01-01

We consider symplectic time integrators in numerical general relativity and discuss both free and constrained evolution schemes. For free evolution of ADM-like equations we propose the use of the Stoermer-Verlet method, a standard symplectic integrator which here is explicit in the computationally expensive curvature terms. For the constrained evolution we give a formulation of the evolution equations that enforces the momentum constraints in a holonomically constrained Hamiltonian system and turns the Hamilton constraint function from a weak to a strong invariant of the system. This formulation permits the use of the constraint-preserving symplectic RATTLE integrator, a constrained version of the Stoermer-Verlet method. The behavior of the methods is illustrated on two effectively (1+1)-dimensional versions of Einstein's equations, which allow us to investigate a perturbed Minkowski problem and the Schwarzschild spacetime. We compare symplectic and non-symplectic integrators for free evolution, showing very different numerical behavior for nearly-conserved quantities in the perturbed Minkowski problem. Further we compare free and constrained evolution, demonstrating in our examples that enforcing the momentum constraints can turn an unstable free evolution into a stable constrained evolution. This is demonstrated in the stabilization of a perturbed Minkowski problem with Dirac gauge, and in the suppression of the propagation of boundary instabilities into the interior of the domain in Schwarzschild spacetime

CENTERA: A Centralized Trust-Based Efficient Routing Protocol with Authentication for Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Ayman Tajeddine

2015-02-01

Full Text Available In this paper, we present CENTERA, a CENtralized Trust-based Efficient Routing protocol with an appropriate authentication scheme for wireless sensor networks (WSN. CENTERA utilizes the more powerful base station (BS to gather minimal neighbor trust information from nodes and calculate the best routes after isolating different types of “bad” nodes. By periodically accumulating these simple local observations and approximating the nodes’ battery lives, the BS draws a global view of the network, calculates three quality metrics—maliciousness, cooperation, and compatibility—and evaluates the Data Trust and Forwarding Trust values of each node. Based on these metrics, the BS isolates “bad”, “misbehaving” or malicious nodes for a certain period, and put some nodes on probation. CENTERA increases the node’s bad/probation level with repeated “bad” behavior, and decreases it otherwise. Then it uses a very efficient method to distribute the routing information to “good” nodes. Based on its target environment, and if required, CENTERA uses an authentication scheme suitable for severely constrained nodes, ranging from the symmetric RC5 for safe environments under close administration, to pairing-based cryptography (PBC for hostile environments with a strong attacker model. We simulate CENTERA using TOSSIM and verify its correctness and show some energy calculations.

CENTERA: a centralized trust-based efficient routing protocol with authentication for wireless sensor networks.

Science.gov (United States)

Tajeddine, Ayman; Kayssi, Ayman; Chehab, Ali; Elhajj, Imad; Itani, Wassim

2015-02-02

In this paper, we present CENTERA, a CENtralized Trust-based Efficient Routing protocol with an appropriate authentication scheme for wireless sensor networks (WSN). CENTERA utilizes the more powerful base station (BS) to gather minimal neighbor trust information from nodes and calculate the best routes after isolating different types of "bad" nodes. By periodically accumulating these simple local observations and approximating the nodes' battery lives, the BS draws a global view of the network, calculates three quality metrics-maliciousness, cooperation, and compatibility-and evaluates the Data Trust and Forwarding Trust values of each node. Based on these metrics, the BS isolates "bad", "misbehaving" or malicious nodes for a certain period, and put some nodes on probation. CENTERA increases the node's bad/probation level with repeated "bad" behavior, and decreases it otherwise. Then it uses a very efficient method to distribute the routing information to "good" nodes. Based on its target environment, and if required, CENTERA uses an authentication scheme suitable for severely constrained nodes, ranging from the symmetric RC5 for safe environments under close administration, to pairing-based cryptography (PBC) for hostile environments with a strong attacker model. We simulate CENTERA using TOSSIM and verify its correctness and show some energy calculations.

A Practical Route Search System for Amusement Parks Navigation

Directory of Open Access Journals (Sweden)

Takahiro Shibuya

2013-12-01

Full Text Available It is very difficult to find the minimum route to travel in amusement park navigation. A searching system for visitors would be useful. Therefore, we constructed a system to find the route with the minimum total traveling time. Facility visitors can employ this system on a smart phone. The system is composed of Java and a Java Servlet. We conclude that our system is useful and can greatly shorten travel time within a typical amusement park.

Efficient Secure and Privacy-Preserving Route Reporting Scheme for VANETs

Science.gov (United States)

Zhang, Yuanfei; Pei, Qianwen; Dai, Feifei; Zhang, Lei

2017-10-01

Vehicular ad-hoc network (VANET) is a core component of intelligent traffic management system which could provide various of applications such as accident prediction, route reporting, etc. Due to the problems caused by traffic congestion, route reporting becomes a prospective application which can help a driver to get optimal route to save her travel time. Before enjoying the convenience of route reporting, security and privacy-preserving issues need to be concerned. In this paper, we propose a new secure and privacy-preserving route reporting scheme for VANETs. In our scheme, only an authenticated vehicle can use the route reporting service provided by the traffic management center. Further, a vehicle may receive the response from the traffic management center with low latency and without violating the privacy of the vehicle. Experiment results show that our scheme is much more efficiency than the existing one.

On Tree-Constrained Matchings and Generalizations

NARCIS (Netherlands)

S. Canzar (Stefan); K. Elbassioni; G.W. Klau (Gunnar); J. Mestre

2011-01-01

htmlabstractWe consider the following \\textsc{Tree-Constrained Bipartite Matching} problem: Given two rooted trees $T_1=(V_1,E_1)$, $T_2=(V_2,E_2)$ and a weight function $w: V_1\\times V_2 \\mapsto \\mathbb{R}_+$, find a maximum weight matching $\\mathcal{M}$ between nodes of the two trees, such that

Route churn: an analysis of low-cost carrier route continuity in Europe

NARCIS (Netherlands)

de Wit, J.G.; Zuidberg, J.

2016-01-01

Discontinuity of air routes is a subject that has been analysed in various ways. For example, the complex network approach focuses on network robustness and resilience due to route interruptions during a relatively short period. Also seasonal interruptions of air routes are a well-documented

Estimating Common Pedestrian Routes through Indoor Path Networks using Position Traces

DEFF Research Database (Denmark)

Prentow, Thor Siiger; Blunck, Henrik; Grønbæk, Kaj

2014-01-01

routes between locations. These methods are sufficiently efficient to provide common routes based on real-time data from thousands of devices simultaneously. Furthermore, we show that the methods operate robustly even on basis of noisy and coarse-grained position estimates as provided by large......Abstract—Accurate information about how people commonly travel in a given large-scale building environment and which routes they take for given start and destination points is essential for applications such as indoor navigation, route prediction, and mobile work planning and logistics...

Cosmogenic photons strongly constrain UHECR source models

Directory of Open Access Journals (Sweden)

van Vliet Arjen

2017-01-01

Full Text Available With the newest version of our Monte Carlo code for ultra-high-energy cosmic ray (UHECR propagation, CRPropa 3, the flux of neutrinos and photons due to interactions of UHECRs with extragalactic background light can be predicted. Together with the recently updated data for the isotropic diffuse gamma-ray background (IGRB by Fermi LAT, it is now possible to severely constrain UHECR source models. The evolution of the UHECR sources especially plays an important role in the determination of the expected secondary photon spectrum. Pure proton UHECR models are already strongly constrained, primarily by the highest energy bins of Fermi LAT’s IGRB, as long as their number density is not strongly peaked at recent times.

Two-dimensional and 3-D images of thick tissue using time-constrained times-of-flight and absorbance spectrophotometry

Science.gov (United States)

Benaron, David A.; Lennox, M.; Stevenson, David K.

1992-05-01

Reconstructing deep-tissue images in real time using spectrophotometric data from optically diffusing thick tissues has been problematic. Continuous wave applications (e.g., pulse oximetry, regional cerebral saturation) ignore both the multiple paths traveled by the photons through the tissue and the effects of scattering, allowing scalar measurements but only under limited conditions; interferometry works poorly in thick, highly-scattering media; frequency- modulated approaches may not allow full deconvolution of scattering and absorbance; and pulsed-light techniques allow for preservation of information regarding the multiple paths taken by light through the tissue, but reconstruction is both computation intensive and limited by the relative surface area available for detection of photons. We have developed a picosecond times-of-flight and absorbance (TOFA) optical system, time-constrained to measure only photons with a narrow range of path lengths and arriving within a narrow angel of the emitter-detector axis. The delay until arrival of the earliest arriving photons is a function of both the scattering and absorbance of the tissues in a direct line between the emitter and detector, reducing the influence of surrounding tissues. Measurement using a variety of emitter and detector locations produces spatial information which can be analyzed in a standard 2-D grid, or subject to computer reconstruction to produce tomographic images representing 3-D structure. Using such a technique, we have been able to demonstrate the principles of tc-TOFA, detect and localize diffusive and/or absorptive objects suspended in highly scattering media (such as blood admixed with yeast), and perform simple 3-D reconstructions using phantom objects. We are now attempting to obtain images in vivo. Potential future applications include use as a research tool, and as a continuous, noninvasive, nondestructive monitor in diagnostic imaging, fetal monitoring, neurologic and cardiac

Preventing Restricted Space Inference in Online Route Planning Services

Directory of Open Access Journals (Sweden)

Florian Dorfmeister

2016-03-01

Full Text Available Online route planning services compute routes from any given location to a desired destination address. Unlike offline implementations, they do so in a traffic-aware fashion by taking into consideration up-to-date map data and real-time traffic information. In return, users have to provide precise location information about a route’s endpoints to a not necessarily trusted service provider. As suchlike leakage of personal information threatens a user’s privacy and anonymity, this paper presents PrOSPR, a comprehensive approach for using current online route planning services in a privacy-preserving way, and introduces the concept of k-immune route requests to avert inference attacks based on restricted space information. Using a map-based approach for creating cloaked regions for the start and destination addresses, our solution queries the online service for routes between subsets of points from these regions. This, however, might result in the returned path deviating from the optimal route. By means of empirical evaluation on a real road network, we demonstrate the feasibility of our approach regarding quality of service and communication overhead.

Inventory slack routing application in emergency logistics and relief distributions.

Science.gov (United States)

Yang, Xianfeng; Hao, Wei; Lu, Yang

2018-01-01

Various natural and manmade disasters during last decades have highlighted the need of further improving on governmental preparedness to emergency events, and a relief supplies distribution problem named Inventory Slack Routing Problem (ISRP) has received increasing attentions. In an ISRP, inventory slack is defined as the duration between reliefs arriving time and estimated inventory stock-out time. Hence, a larger inventory slack could grant more responsive time in facing of various factors (e.g., traffic congestion) that may lead to delivery lateness. In this study, the relief distribution problem is formulated as an optimization model that maximize the minimum slack among all dispensing sites. To efficiently solve this problem, we propose a two-stage approach to tackle the vehicle routing and relief allocation sub-problems. By analyzing the inter-relations between these two sub-problems, a new objective function considering both delivery durations and dispensing rates of demand sites is applied in the first stage to design the vehicle routes. A hierarchical routing approach and a sweep approach are also proposed in this stage. Given the vehicle routing plan, the relief allocation could be easily solved in the second stage. Numerical experiment with a comparison of multi-vehicle Traveling Salesman Problem (TSP) has demonstrated the need of ISRP and the capability of the proposed solution approaches.

Formal language constrained path problems

Energy Technology Data Exchange (ETDEWEB)

Barrett, C.; Jacob, R.; Marathe, M.

1997-07-08

In many path finding problems arising in practice, certain patterns of edge/vertex labels in the labeled graph being traversed are allowed/preferred, while others are disallowed. Motivated by such applications as intermodal transportation planning, the authors investigate the complexity of finding feasible paths in a labeled network, where the mode choice for each traveler is specified by a formal language. The main contributions of this paper include the following: (1) the authors show that the problem of finding a shortest path between a source and destination for a traveler whose mode choice is specified as a context free language is solvable efficiently in polynomial time, when the mode choice is specified as a regular language they provide algorithms with improved space and time bounds; (2) in contrast, they show that the problem of finding simple paths between a source and a given destination is NP-hard, even when restricted to very simple regular expressions and/or very simple graphs; (3) for the class of treewidth bounded graphs, they show that (i) the problem of finding a regular language constrained simple path between source and a destination is solvable in polynomial time and (ii) the extension to finding context free language constrained simple paths is NP-complete. Several extensions of these results are presented in the context of finding shortest paths with additional constraints. These results significantly extend the results in [MW95]. As a corollary of the results, they obtain a polynomial time algorithm for the BEST k-SIMILAR PATH problem studied in [SJB97]. The previous best algorithm was given by [SJB97] and takes exponential time in the worst case.

Constrained evolution in numerical relativity

Science.gov (United States)

Anderson, Matthew William

The strongest potential source of gravitational radiation for current and future detectors is the merger of binary black holes. Full numerical simulation of such mergers can provide realistic signal predictions and enhance the probability of detection. Numerical simulation of the Einstein equations, however, is fraught with difficulty. Stability even in static test cases of single black holes has proven elusive. Common to unstable simulations is the growth of constraint violations. This work examines the effect of controlling the growth of constraint violations by solving the constraints periodically during a simulation, an approach called constrained evolution. The effects of constrained evolution are contrasted with the results of unconstrained evolution, evolution where the constraints are not solved during the course of a simulation. Two different formulations of the Einstein equations are examined: the standard ADM formulation and the generalized Frittelli-Reula formulation. In most cases constrained evolution vastly improves the stability of a simulation at minimal computational cost when compared with unconstrained evolution. However, in the more demanding test cases examined, constrained evolution fails to produce simulations with long-term stability in spite of producing improvements in simulation lifetime when compared with unconstrained evolution. Constrained evolution is also examined in conjunction with a wide variety of promising numerical techniques, including mesh refinement and overlapping Cartesian and spherical computational grids. Constrained evolution in boosted black hole spacetimes is investigated using overlapping grids. Constrained evolution proves to be central to the host of innovations required in carrying out such intensive simulations.

Sternal Route More Effective than Tibial Route for Intraosseous Amiodarone Administration in a Swine Model of Ventricular Fibrillation.

Science.gov (United States)

Burgert, James M; Martinez, Andre; O'Sullivan, Mara; Blouin, Dawn; Long, Audrey; Johnson, Arthur D

2018-01-01

The pharmacokinetics of IO administered lipid soluble amiodarone during ventricular fibrillation (VF) with ongoing CPR are unknown. This study measured mean plasma concentration over 5 minutes, maximum plasma concentration (Cmax), and time to maximum concentration (Tmax) of amiodarone administered by the sternal IO (SIO), tibial IO (TIO), and IV routes in a swine model of VF with ongoing CPR. Twenty-one Yorkshire-cross swine were randomly assigned to three groups: SIO, TIO, and IV. Ventricular fibrillation was induced under general anesthesia. After 4 minutes in VF, 300 mg amiodarone was administered as indicated by group assignment. Serial blood specimens collected at 30, 60, 90, 120, 150, 180, 240, and 300 seconds were analyzed using high performance liquid chromatography with tandem mass spectrometry. The mean plasma concentration of IV amiodarone over 5 minutes was significantly higher than the TIO group at 60 seconds (P = 0.02) and 90 seconds (P = 0.017) post-injection. No significant differences in Cmax between the groups were found (P <0.05). The Tmax of amiodarone was significantly shorter in the SIO (99 secs) and IV (86 secs) groups compared to the TIO group (215 secs); P = 0.002 and P = 0.002, respectively. The SIO and IV routes of amiodarone administration were comparable. The TIO group took nearly three times longer to reach Tmax than the SIO and IV groups, likely indicating depot of lipid-soluble amiodarone in adipose-rich tibial yellow bone marrow. The SIO route was more effective than the TIO route for amiodarone delivery in a swine model of VF with ongoing CPR. Further investigations are necessary to determine if the kinetic differences found between the SIO and TIO routes in this study affect survival of VF in humans.

Receiver-Based Ad Hoc On Demand Multipath Routing Protocol for Mobile Ad Hoc Networks.

Science.gov (United States)

Al-Nahari, Abdulaziz; Mohamad, Mohd Murtadha

2016-01-01

Decreasing the route rediscovery time process in reactive routing protocols is challenging in mobile ad hoc networks. Links between nodes are continuously established and broken because of the characteristics of the network. Finding multiple routes to increase the reliability is also important but requires a fast update, especially in high traffic load and high mobility where paths can be broken as well. The sender node keeps re-establishing path discovery to find new paths, which makes for long time delay. In this paper we propose an improved multipath routing protocol, called Receiver-based ad hoc on demand multipath routing protocol (RB-AOMDV), which takes advantage of the reliability of the state of the art ad hoc on demand multipath distance vector (AOMDV) protocol with less re-established discovery time. The receiver node assumes the role of discovering paths when finding data packets that have not been received after a period of time. Simulation results show the delay and delivery ratio performances are improved compared with AOMDV.

CENTERA: A Centralized Trust-Based Efficient Routing Protocol with Authentication for Wireless Sensor Networks †

Science.gov (United States)

Tajeddine, Ayman; Kayssi, Ayman; Chehab, Ali; Elhajj, Imad; Itani, Wassim

2015-01-01

In this paper, we present CENTERA, a CENtralized Trust-based Efficient Routing protocol with an appropriate authentication scheme for wireless sensor networks (WSN). CENTERA utilizes the more powerful base station (BS) to gather minimal neighbor trust information from nodes and calculate the best routes after isolating different types of “bad” nodes. By periodically accumulating these simple local observations and approximating the nodes' battery lives, the BS draws a global view of the network, calculates three quality metrics—maliciousness, cooperation, and compatibility—and evaluates the Data Trust and Forwarding Trust values of each node. Based on these metrics, the BS isolates “bad”, “misbehaving” or malicious nodes for a certain period, and put some nodes on probation. CENTERA increases the node's bad/probation level with repeated “bad” behavior, and decreases it otherwise. Then it uses a very efficient method to distribute the routing information to “good” nodes. Based on its target environment, and if required, CENTERA uses an authentication scheme suitable for severely constrained nodes, ranging from the symmetric RC5 for safe environments under close administration, to pairing-based cryptography (PBC) for hostile environments with a strong attacker model. We simulate CENTERA using TOSSIM and verify its correctness and show some energy calculations. PMID:25648712

Intermittency route to chaos in a biochemical system.

Science.gov (United States)

De la Fuente, I M; Martinez, L; Veguillas, J

1996-01-01

The numerical analysis of a glycolytic model performed through the construction of a system of three differential-delay equations reveals a phenomenon of intermittency route to chaos. In our biochemical system, the consideration of delay time variations under constant input flux as well as frequency variations of the periodic substrate input flux allows us, in both cases, to observe a type of transition to chaos different from the 'Feigenbaum route'.

Hazmat Routes (National)

Data.gov (United States)

Department of Transportation — The Federal Motor Carrier Safety Administration (FMCSA) Hazardous Material Routes (NTAD) were developed using the 2004 First Edition TIGER/Line files. The routes are...

Capacitated arc routing problem and its extensions in waste collection

International Nuclear Information System (INIS)

Fadzli, Mohammad; Najwa, Nurul; Luis, Martino

2015-01-01

Capacitated arc routing problem (CARP) is the youngest generation of graph theory that focuses on solving the edge/arc routing for optimality. Since many years, operational research devoted to CARP counterpart, known as vehicle routing problem (VRP), which does not fit to several real cases such like waste collection problem and road maintenance. In this paper, we highlighted several extensions of capacitated arc routing problem (CARP) that represents the real-life problem of vehicle operation in waste collection. By purpose, CARP is designed to find a set of routes for vehicles that satisfies all pre-setting constraints in such that all vehicles must start and end at a depot, service a set of demands on edges (or arcs) exactly once without exceeding the capacity, thus the total fleet cost is minimized. We also addressed the differentiation between CARP and VRP in waste collection. Several issues have been discussed including stochastic demands and time window problems in order to show the complexity and importance of CARP in the related industry. A mathematical model of CARP and its new version is presented by considering several factors such like delivery cost, lateness penalty and delivery time

Extended shortest path selection for package routing of complex networks

Science.gov (United States)

Ye, Fan; Zhang, Lei; Wang, Bing-Hong; Liu, Lu; Zhang, Xing-Yi

The routing strategy plays a very important role in complex networks such as Internet system and Peer-to-Peer networks. However, most of the previous work concentrates only on the path selection, e.g. Flooding and Random Walk, or finding the shortest path (SP) and rarely considering the local load information such as SP and Distance Vector Routing. Flow-based Routing mainly considers load balance and still cannot achieve best optimization. Thus, in this paper, we propose a novel dynamic routing strategy on complex network by incorporating the local load information into SP algorithm to enhance the traffic flow routing optimization. It was found that the flow in a network is greatly affected by the waiting time of the network, so we should not consider only choosing optimized path for package transformation but also consider node congestion. As a result, the packages should be transmitted with a global optimized path with smaller congestion and relatively short distance. Analysis work and simulation experiments show that the proposed algorithm can largely enhance the network flow with the maximum throughput within an acceptable calculating time. The detailed analysis of the algorithm will also be provided for explaining the efficiency.

Capacitated arc routing problem and its extensions in waste collection

Energy Technology Data Exchange (ETDEWEB)

Fadzli, Mohammad; Najwa, Nurul [Institut Matematik Kejuruteraan, Universiti Malaysia Perlis, Kampus Pauh Putra, 02600 Arau, Perlis (Malaysia); Luis, Martino [Othman Yeop Abdullah Graduate School of Business, Universiti Utara Malaysia, 06010 Sintok, Kedah (Malaysia)

2015-05-15

Capacitated arc routing problem (CARP) is the youngest generation of graph theory that focuses on solving the edge/arc routing for optimality. Since many years, operational research devoted to CARP counterpart, known as vehicle routing problem (VRP), which does not fit to several real cases such like waste collection problem and road maintenance. In this paper, we highlighted several extensions of capacitated arc routing problem (CARP) that represents the real-life problem of vehicle operation in waste collection. By purpose, CARP is designed to find a set of routes for vehicles that satisfies all pre-setting constraints in such that all vehicles must start and end at a depot, service a set of demands on edges (or arcs) exactly once without exceeding the capacity, thus the total fleet cost is minimized. We also addressed the differentiation between CARP and VRP in waste collection. Several issues have been discussed including stochastic demands and time window problems in order to show the complexity and importance of CARP in the related industry. A mathematical model of CARP and its new version is presented by considering several factors such like delivery cost, lateness penalty and delivery time.

Efficient priority queueing routing strategy on networks of mobile agents

Science.gov (United States)

Wu, Gan-Hua; Yang, Hui-Jie; Pan, Jia-Hui

2018-03-01

As a consequence of their practical implications for communications networks, traffic dynamics on complex networks have recently captivated researchers. Previous routing strategies for improving transport efficiency have paid little attention to the orders in which the packets should be forwarded, just simply used first-in-first-out queue discipline. Here, we apply a priority queuing discipline and propose a shortest-distance-first routing strategy on networks of mobile agents. Numerical experiments reveal that the proposed scheme remarkably improves both the network throughput and the packet arrival rate and reduces both the average traveling time and the rate of waiting time to traveling time. Moreover, we find that the network capacity increases with an increase in both the communication radius and the number of agents. Our work may be helpful for the design of routing strategies on networks of mobile agents.

Energy Aware Cluster Based Routing Scheme For Wireless Sensor Network

Directory of Open Access Journals (Sweden)

Roy Sohini

2015-09-01

Full Text Available Wireless Sensor Network (WSN has emerged as an important supplement to the modern wireless communication systems due to its wide range of applications. The recent researches are facing the various challenges of the sensor network more gracefully. However, energy efficiency has still remained a matter of concern for the researches. Meeting the countless security needs, timely data delivery and taking a quick action, efficient route selection and multi-path routing etc. can only be achieved at the cost of energy. Hierarchical routing is more useful in this regard. The proposed algorithm Energy Aware Cluster Based Routing Scheme (EACBRS aims at conserving energy with the help of hierarchical routing by calculating the optimum number of cluster heads for the network, selecting energy-efficient route to the sink and by offering congestion control. Simulation results prove that EACBRS performs better than existing hierarchical routing algorithms like Distributed Energy-Efficient Clustering (DEEC algorithm for heterogeneous wireless sensor networks and Energy Efficient Heterogeneous Clustered scheme for Wireless Sensor Network (EEHC.

An Emergency-Adaptive Routing Scheme for Wireless Sensor Networks for Building Fire Hazard Monitoring

Directory of Open Access Journals (Sweden)

Guilin Zheng

2011-03-01

Full Text Available Fire hazard monitoring and evacuation for building environments is a novel application area for the deployment of wireless sensor networks. In this context, adaptive routing is essential in order to ensure safe and timely data delivery in building evacuation and fire fighting resource applications. Existing routing mechanisms for wireless sensor networks are not well suited for building fires, especially as they do not consider critical and dynamic network scenarios. In this paper, an emergency-adaptive, real-time and robust routing protocol is presented for emergency situations such as building fire hazard applications. The protocol adapts to handle dynamic emergency scenarios and works well with the routing hole problem. Theoretical analysis and simulation results indicate that our protocol provides a real-time routing mechanism that is well suited for dynamic emergency scenarios in building fires when compared with other related work.

Dynamic Vehicle Routing Using an Improved Variable Neighborhood Search Algorithm

Directory of Open Access Journals (Sweden)

Yingcheng Xu

2013-01-01

Full Text Available In order to effectively solve the dynamic vehicle routing problem with time windows, the mathematical model is established and an improved variable neighborhood search algorithm is proposed. In the algorithm, allocation customers and planning routes for the initial solution are completed by the clustering method. Hybrid operators of insert and exchange are used to achieve the shaking process, the later optimization process is presented to improve the solution space, and the best-improvement strategy is adopted, which make the algorithm can achieve a better balance in the solution quality and running time. The idea of simulated annealing is introduced to take control of the acceptance of new solutions, and the influences of arrival time, distribution of geographical location, and time window range on route selection are analyzed. In the experiment, the proposed algorithm is applied to solve the different sizes' problems of DVRP. Comparing to other algorithms on the results shows that the algorithm is effective and feasible.

Improvement of Network Performance by In-Vehicle Routing Using Floating Car Data

Directory of Open Access Journals (Sweden)

Gerdien A. Klunder

2017-01-01

Full Text Available This paper describes a study which gives insight into the size of improvement that is possible with individual in-car routing advice based on the actual traffic situation derived from floating car data (FCD. It also gives an idea about the required penetration rate of floating car data needed to achieve a certain degree of improvement. The study uses real loop detector data from the region of Amsterdam collected for over a year, a route generating algorithm for in-car routing advice, and emulated floating car data to generate the routing advice. The case with in-car routing advice has been compared to the base case, where drivers base their routing decisions on average knowledge of travel times in the network. The improvement in total delay using the in-vehicle system is dependent on penetration rate and accuracy of the floating car data and varies from 2.0% to 3.4% for 10% penetration rate. This leads to yearly savings of about 15 million euros if delay is monetarised using standard prices for value of time (VOT.

Route planning with transportation network maps: an eye-tracking study.

Science.gov (United States)

Grison, Elise; Gyselinck, Valérie; Burkhardt, Jean-Marie; Wiener, Jan Malte

2017-09-01

Planning routes using transportation network maps is a common task that has received little attention in the literature. Here, we present a novel eye-tracking paradigm to investigate psychological processes and mechanisms involved in such a route planning. In the experiment, participants were first presented with an origin and destination pair before we presented them with fictitious public transportation maps. Their task was to find the connecting route that required the minimum number of transfers. Based on participants' gaze behaviour, each trial was split into two phases: (1) the search for origin and destination phase, i.e., the initial phase of the trial until participants gazed at both origin and destination at least once and (2) the route planning and selection phase. Comparisons of other eye-tracking measures between these phases and the time to complete them, which depended on the complexity of the planning task, suggest that these two phases are indeed distinct and supported by different cognitive processes. For example, participants spent more time attending the centre of the map during the initial search phase, before directing their attention to connecting stations, where transitions between lines were possible. Our results provide novel insights into the psychological processes involved in route planning from maps. The findings are discussed in relation to the current theories of route planning.

Intelligent QoS routing algorithm based on improved AODV protocol for Ad Hoc networks

Science.gov (United States)

Huibin, Liu; Jun, Zhang

2016-04-01

Mobile Ad Hoc Networks were playing an increasingly important part in disaster reliefs, military battlefields and scientific explorations. However, networks routing difficulties are more and more outstanding due to inherent structures. This paper proposed an improved cuckoo searching-based Ad hoc On-Demand Distance Vector Routing protocol (CSAODV). It elaborately designs the calculation methods of optimal routing algorithm used by protocol and transmission mechanism of communication-package. In calculation of optimal routing algorithm by CS Algorithm, by increasing QoS constraint, the found optimal routing algorithm can conform to the requirements of specified bandwidth and time delay, and a certain balance can be obtained among computation spending, bandwidth and time delay. Take advantage of NS2 simulation software to take performance test on protocol in three circumstances and validate the feasibility and validity of CSAODV protocol. In results, CSAODV routing protocol is more adapt to the change of network topological structure than AODV protocol, which improves package delivery fraction of protocol effectively, reduce the transmission time delay of network, reduce the extra burden to network brought by controlling information, and improve the routing efficiency of network.

A reliability-based approach of fastest routes planning in dynamic traffic network under emergency management situation

Directory of Open Access Journals (Sweden)

Ye Sun

2011-12-01

Full Text Available In order to establish an available emergency management system, it is important to conduct effective evacuation with reliable and real time optimal route plans. This paper aims at creating a route finding strategy by considering the time dependent factors as well as uncertainties that may be encountered during the emergency management system. To combine dynamic features with the level of reliability in the process of fastest route planning, the speed distribution of typical intercity roads is studied in depth, and the strategy of modifying real time speed to a more reliable value based on speed distribution is proposed. Two algorithms of route planning have been developed to find three optimal routes with the shortest travel time and the reliability of 0.9. In order to validate the new strategy, experimental implementation of the route planning method is conducted based on road speed information acquired by field study. The results show that the proposed strategy might provide more reliable routes in dynamic traffic networks by conservatively treating roads with large speed discretion or with relative extreme real speed value.

Eco-routing: More green drivers means more benefits?

Energy Technology Data Exchange (ETDEWEB)

Valdes Serrano, C.; Perez Prada, F.; Monzon de Caceres, A.

2016-07-01

Information and Communications Technology (ICT)/Information and Technology Services (ITS) can play an important role in the transport sector, helping in maintaining accessibility and contemporarily optimizing the use of the vehicles. Among these ICT measures, eco-routing seems a promising one. Drivers normally follow the route which minimizes their generalized costs, normally time and money. But environmental concern is increasing, and drivers are starting to think about the effects of their driving. This means including CO2 emissions or fuel consumption in their route choice. But is this always positive, independently of the traffic situation and the penetration level of green drivers? This articles aims to analyze what happens in terms of fuel consumption, CO2 emissions and travel time, when different penetration levels of drivers, and with different traffic situations, follow the route of minimum fuel consumption instead of the conventional generalized costs. The analysis is based on a modelling process using a transport model of the whole region of Madrid. A total of 18 scenarios are considered: 3 reference scenarios (for congested, medium and low flow traffic situations), and 5 different penetration levels of green drivers for each traffic situation. Results show how impact varies substantially with the level of traffic and, also, that the more the best is not always true. (Author)

ARBR: Adaptive reinforcement-based routing for DTN

KAUST Repository

Elwhishi, Ahmed

2010-10-01

This paper introduces a novel routing protocol in Delay Tolerant Networks (DTNs), aiming to solve the online distributed routing problem. By manipulating a collaborative reinforcement learning technique, a group of nodes can cooperate with each other and make a forwarding decision for the stored messages based on a cost function at each contact with another node. The proposed protocol is characterized by not only considering the contact time statistics under a novel contact model, but also looks into the feedback on user behavior and network conditions, such as congestion and buffer occupancy sampled during each previous contact with any other node. Therefore, the proposed protocol can achieve high efficiency via an adaptive and intelligent routing mechanism according to network conditions. Extensive simulation is conducted to verify the proposed protocol, where a comparison is made with a number of existing encounter-based routing protocols in term of the number of transmissions of each message, message delivery delay, and delivery ratio. The results of the simulation demonstrate the effectiveness of the proposed technique.

A fully distributed geo-routing scheme for wireless sensor networks

KAUST Repository

Bader, Ahmed

2013-12-01

When marrying randomized distributed space-time coding (RDSTC) to beaconless geo-routing, new performance horizons can be created. In order to reach those horizons, however, beaconless geo-routing protocols must evolve to operate in a fully distributed fashion. In this letter, we expose a technique to construct a fully distributed geo-routing scheme in conjunction with RDSTC. We then demonstrate the performance gains of this novel scheme by comparing it to one of the prominent classical schemes. © 2013 IEEE.

A fully distributed geo-routing scheme for wireless sensor networks

KAUST Repository

Bader, Ahmed; Abed-Meraim, Karim; Alouini, Mohamed-Slim

2013-01-01

When marrying randomized distributed space-time coding (RDSTC) to beaconless geo-routing, new performance horizons can be created. In order to reach those horizons, however, beaconless geo-routing protocols must evolve to operate in a fully distributed fashion. In this letter, we expose a technique to construct a fully distributed geo-routing scheme in conjunction with RDSTC. We then demonstrate the performance gains of this novel scheme by comparing it to one of the prominent classical schemes. © 2013 IEEE.

Towards seasonal Arctic shipping route predictions

Science.gov (United States)

Haines, K.; Melia, N.; Hawkins, E.; Day, J. J.

2017-12-01

In our previous work [1] we showed how trans-Arctic shipping routes would become more available through the 21st century as sea ice declines, using CMIP5 models with means and stds calibrated to PIOMAS sea ice observations. Sea ice will continue to close shipping routes to open water vessels through the winter months for the foreseeable future so the availability of open sea routes will vary greatly from year to year. Here [2] we look at whether the trans-Arctic shipping season period can be predicted in seasonal forecasts, again using several climate models, and testing both perfect and imperfect knowledge of the initial sea ice conditions. We find skilful predictions of the upcoming summer shipping season can be made from as early as January, although typically forecasts may show lower skill before a May `predictability barrier'. Focussing on the northern sea route (NSR) off Siberia, the date of opening of this sea route is twice as variable as the closing date, and this carries through to reduced predictability at the start of the season. Under climate change the later freeze-up date accounts for 60% of the lengthening season, Fig1 We find that predictive skill is state dependent with predictions for high or low ice years exhibiting greater skill than for average ice years. Forecasting the exact timing of route open periods is harder (more weather dependent) under average ice conditions while in high and low ice years the season is more controlled by the initial ice conditions from spring onwards. This could be very useful information for companies planning vessel routing for the coming season. We tested this dependence on the initial ice conditions by changing the initial ice state towards climatologically average conditions and show directly that early summer sea-ice thickness information is crucial to obtain skilful forecasts of the coming shipping season. Mechanisms for this are discussed. This strongly suggests that good sea ice thickness observations

Optimization Model for Headway of a Suburban Bus Route

Directory of Open Access Journals (Sweden)

Xiaohong Jiang

2014-01-01

Full Text Available Due to relatively low passenger demand, headways of suburban bus route are usually longer than those of urban bus route. Actually it is also difficult to balance the benefits between passengers and operators, subject to the service standards from the government. Hence the headway of a suburban bus route is usually determined on the empirical experience of transport planners. To cope with this problem, this paper proposes an optimization model for designing the headways of suburban bus routes by minimizing the operating and user costs. The user costs take into account both the waiting time cost and the crowding cost. The feasibility and validity of the proposed model are shown by applying it to the Route 206 in Jiangning district, Nanjing city of China. Weightages of passengers’ cost and operating cost are further discussed, considering different passenger flows. It is found that the headway and objective function are affected by the weightages largely.

A Preemptive Link State Spanning Tree Source Routing Scheme for Opportunistic Data Forwarding in MANET

OpenAIRE

R. Poonkuzhali; M. Y. Sanavullah; A. Sabari

2014-01-01

Opportunistic Data Forwarding (ODF) has drawn much attention in mobile adhoc networking research in recent years. The effectiveness of ODF in MANET depends on a suitable routing protocol which provides a powerful source routing services. PLSR is featured by source routing, loop free and small routing overhead. The update messages in PLSR are integrated into a tree structure and no need to time stamp routing updates which reduces the routing overhead.

Air Cargo Transportation Route Choice Analysis

Science.gov (United States)

Obashi, Hiroshi; Kim, Tae-Seung; Oum, Tae Hoon

2003-01-01

Using a unique feature of air cargo transshipment data in the Northeast Asian region, this paper identifies the critical factors that determine the transshipment route choice. Taking advantage of the variations in the transport characteristics in each origin-destination airports pair, the paper uses a discrete choice model to describe the transshipping route choice decision made by an agent (i.e., freight forwarder, consolidator, and large shipper). The analysis incorporates two major factors, monetary cost (such as line-haul cost and landing fee) and time cost (i.e., aircraft turnaround time, including loading and unloading time, custom clearance time, and expected scheduled delay), along with other controls. The estimation method considers the presence of unobserved attributes, and corrects for resulting endogeneity by use of appropriate instrumental variables. Estimation results find that transshipment volumes are more sensitive to time cost, and that the reduction in aircraft turnaround time by 1 hour would be worth the increase in airport charges by more than $1000. Simulation exercises measures the impacts of alternative policy scenarios for a Korean airport, which has recently declared their intention to be a future regional hub in the Northeast Asian region. The results suggest that reducing aircraft turnaround time at the airport be an effective strategy, rather than subsidizing to reduce airport charges.

Long-term changes in migration timing of Song Thrush Turdus philomelos at the southern Baltic coast in response to temperatures on route and at breeding grounds.

Science.gov (United States)

Redlisiak, Michał; Remisiewicz, Magdalena; Nowakowski, Jarosław K

2018-05-26

Climate warming causes the advancement of spring arrival of many migrant birds breeding in Europe, but the effects on their autumn migration are less known. We aimed to determine any changes in the timing of Song Thrush captured during spring and autumn migrations at the Polish Baltic coast from 1975 to 2014, and if these were related to long-term changes of temperature at their breeding grounds and migration routes. The timing of spring migration at Hel ringing station in 1975-2014 did not show long-term advance, but they had responded to environmental conditions on the year-to-year basis. The warmer the temperatures were in April on their migration route, the earlier were the dates of the median and the end of spring migration at Hel. The beginning of autumn migration at the Mierzeja Wiślana ringing station advanced by 5 days between 1975 and 2014. The warmer the April on route, and the July at the Song Thrushes' breeding grounds, the earlier young birds began autumn migration across the Baltic coast. We suggest this was a combined effect of adults' migration and breeding early during warm springs and young birds getting ready faster for autumn migration during warm summers. The average time span of 90% of the autumn migration was extended by 5 days, probably because of early migration of young birds from first broods and late of those from second broods enabled by warm springs and summers. The response of Song Thrushes' migration timing to temperatures on route and at the breeding grounds indicated high plasticity in the species and suggested it might adapt well to climate changes.

COORDINATION OF THE WORK OF BUSES IN CITY ROUTES

Directory of Open Access Journals (Sweden)

Fuad DASHDAMIROV

2013-12-01

Full Text Available The paper studied the work of bus routes passing through a street. Optimality criterion was chosen for the development of appropriate models of effective work of buses on the land. The paper proposes a new model costing time passengers at bus stops. A method of technique was developed to coordinate the buses running on the combined section of route.

Simulated annealing with restart strategy for the blood pickup routing problem

Science.gov (United States)

Yu, V. F.; Iswari, T.; Normasari, N. M. E.; Asih, A. M. S.; Ting, H.

2018-04-01

This study develops a simulated annealing heuristic with restart strategy (SA_RS) for solving the blood pickup routing problem (BPRP). BPRP minimizes the total length of the routes for blood bag collection between a blood bank and a set of donation sites, each associated with a time window constraint that must be observed. The proposed SA_RS is implemented in C++ and tested on benchmark instances of the vehicle routing problem with time windows to verify its performance. The algorithm is then tested on some newly generated BPRP instances and the results are compared with those obtained by CPLEX. Experimental results show that the proposed SA_RS heuristic effectively solves BPRP.

Cosmicflows Constrained Local UniversE Simulations

Science.gov (United States)

Sorce, Jenny G.; Gottlöber, Stefan; Yepes, Gustavo; Hoffman, Yehuda; Courtois, Helene M.; Steinmetz, Matthias; Tully, R. Brent; Pomarède, Daniel; Carlesi, Edoardo

2016-01-01

This paper combines observational data sets and cosmological simulations to generate realistic numerical replicas of the nearby Universe. The latter are excellent laboratories for studies of the non-linear process of structure formation in our neighbourhood. With measurements of radial peculiar velocities in the local Universe (cosmicflows-2) and a newly developed technique, we produce Constrained Local UniversE Simulations (CLUES). To assess the quality of these constrained simulations, we compare them with random simulations as well as with local observations. The cosmic variance, defined as the mean one-sigma scatter of cell-to-cell comparison between two fields, is significantly smaller for the constrained simulations than for the random simulations. Within the inner part of the box where most of the constraints are, the scatter is smaller by a factor of 2 to 3 on a 5 h-1 Mpc scale with respect to that found for random simulations. This one-sigma scatter obtained when comparing the simulated and the observation-reconstructed velocity fields is only 104 ± 4 km s-1, I.e. the linear theory threshold. These two results demonstrate that these simulations are in agreement with each other and with the observations of our neighbourhood. For the first time, simulations constrained with observational radial peculiar velocities resemble the local Universe up to a distance of 150 h-1 Mpc on a scale of a few tens of megaparsecs. When focusing on the inner part of the box, the resemblance with our cosmic neighbourhood extends to a few megaparsecs (<5 h-1 Mpc). The simulations provide a proper large-scale environment for studies of the formation of nearby objects.

Disruption Management for the Real-Time Home Caregiver Scheduling and Routing Problem

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Biao Yuan

2017-11-01

Full Text Available The aggravating trend of the aging population, the miniaturization of the family structure, and the increase of families with empty nesters greatly affect the sustainable development of the national economy and social old-age security system of China. The emergence of home health care or home care (HHC/HC service mode provides an alternative for elderly care. How to develop and apply this new mobile service mode is crucial for the government. Therefore, the pertinent optimization problems regarding HHC/HC have constantly attracted the attention of researchers. Unexpected events, such as new requests of customers, cancellations of customers’ services, and changes of customers’ time windows, may occur during the process of executing an a priori visiting plan. These events may sometimes make the original plan non-optimal or even infeasible. To cope with this situation, we introduce disruption management to the real-time home caregiver scheduling and routing problem. The deviation measurements on customers, caregivers, and companies are first defined. A mathematical model that minimizes the weighted sum of deviation measurements is then constructed. Next, a tabu search (TS heuristic is developed to efficiently solve the problem, and a cost recorded mechanism is used to strengthen the performance. Finally, by performing computational experiments on three real-life instances, the effectiveness of the TS heuristic is tested, and the advantages of disruption management are analyzed.

Prospect theory based estimation of drivers' risk attitudes in route choice behaviors.

Science.gov (United States)

Zhou, Lizhen; Zhong, Shiquan; Ma, Shoufeng; Jia, Ning

2014-12-01

This paper applied prospect theory (PT) to describe drivers' route choice behavior under Variable Message Sign (VMS), which presented visual traffic information to assist them to make route choice decisions. A quite rich empirical data from questionnaire and field spot was used to estimate parameters of PT. In order to make the parameters more realistic with drivers' attitudes, they were classified into different types by significant factors influencing their behaviors. Based on the travel time distribution of alternative routes and route choice results from questionnaire, the parameterized value function of each category was figured out, which represented drivers' risk attitudes and choice characteristics. The empirical verification showed that the estimates were acceptable and effective. The result showed drivers' risk attitudes and route choice characteristics could be captured by PT under real-time information shown on VMS. For practical application, once drivers' route choice characteristics and parameters were identified, their route choice behavior under different road conditions could be predicted accurately, which was the basis of traffic guidance measures formulation and implementation for targeted traffic management. Moreover, the heterogeneous risk attitudes among drivers should be considered when releasing traffic information and regulating traffic flow. Copyright © 2014 Elsevier Ltd. All rights reserved.

Improved routing strategies for data traffic in scale-free networks

International Nuclear Information System (INIS)

Wu, Zhi-Xi; Peng, Gang; Wong, Wing-Ming; Yeung, Kai-Hau

2008-01-01

We study the information packet routing process in scale-free networks by mimicking Internet traffic delivery. We incorporate both the global shortest paths information and local degree information of the network in the dynamic process, via two tunable parameters, α and β, to guide the packet routing. We measure the performance of the routing method by both the average transit times of packets and the critical packet generation rate (above which packet aggregation occurs in the network). We found that the routing strategies which integrate ingredients of both global and local topological information of the underlying networks perform much better than the traditional shortest path routing protocol taking into account the global topological information only. Moreover, by doing comparative studies with some related works, we found that the performance of our proposed method shows universal efficiency characteristic against the amount of traffic

Biased random key genetic algorithm with insertion and gender selection for capacitated vehicle routing problem with time windows

Science.gov (United States)

Rochman, Auliya Noor; Prasetyo, Hari; Nugroho, Munajat Tri

2017-06-01

Vehicle Routing Problem (VRP) often occurs when the manufacturers need to distribute their product to some customers/outlets. The distribution process is typically restricted by the capacity of the vehicle and the working hours at the distributor. This type of VRP is also known as Capacitated Vehicle Routing Problem with Time Windows (CVRPTW). A Biased Random Key Genetic Algorithm (BRKGA) was designed and coded in MATLAB to solve the CVRPTW case of soft drink distribution. The standard BRKGA was then modified by applying chromosome insertion into the initial population and defining chromosome gender for parent undergoing crossover operation. The performance of the established algorithms was then compared to a heuristic procedure for solving a soft drink distribution. Some findings are revealed (1) the total distribution cost of BRKGA with insertion (BRKGA-I) results in a cost saving of 39% compared to the total cost of heuristic method, (2) BRKGA with the gender selection (BRKGA-GS) could further improve the performance of the heuristic method. However, the BRKGA-GS tends to yield worse results compared to that obtained from the standard BRKGA.

Capacitated Bounded Cardinality Hub Routing Problem: Model and Solution Algorithm

OpenAIRE

Gelareha, Shahin; Monemic, Rahimeh Neamatian; Semetd, Frederic

2017-01-01

In this paper, we address the Bounded Cardinality Hub Location Routing with Route Capacity wherein each hub acts as a transshipment node for one directed route. The number of hubs lies between a minimum and a maximum and the hub-level network is a complete subgraph. The transshipment operations take place at the hub nodes and flow transfer time from a hub-level transporter to a spoke-level vehicle influences spoke- to-hub allocations. We propose a mathematical model and a branch-and-cut algor...

The life and times of the Savings Method for Vehicle Routing Problems

African Journals Online (AJOL)

Forty ve years ago, an academic and practitioner from the north of England published a method of tackling the vehicle routing problem (VRP) in an American journal. Little could they have realised how the method they devised would still be a signicant part of the research agenda nearly half a century later. Adaptations of ...

Vessels Route Planning Problem with Uncertain Data

Directory of Open Access Journals (Sweden)

Tomasz Neumann

2016-09-01

Full Text Available The purpose of this paper is to find a solution for route planning in a transport networks, where the costs of tracks, factor of safety and travel time are ambiguous. This approach is based on the Dempster-Shafer theory and well known Dijkstra's algorithm. In this approach important are the influencing factors of the mentioned coefficients using uncertain possibilities presented by probability intervals. Based on these intervals the quality intervals of each route can be determined. Applied decision rules can be described by the end user.

Multihop Wireless Networks Opportunistic Routing

CERN Document Server

Zeng, Kai; Li, Ming

2011-01-01

This book provides an introduction to opportunistic routing an emerging technology designed to improve the packet forwarding reliability, network capacity and energy efficiency of multihop wireless networks This book presents a comprehensive background to the technological challenges lying behind opportunistic routing. The authors cover many fundamental research issues for this new concept, including the basic principles, performance limit and performance improvement of opportunistic routing compared to traditional routing, energy efficiency and distributed opportunistic routing protocol desig

Dynamic Weather Routes: A Weather Avoidance Concept for Trajectory-Based Operations

Science.gov (United States)

McNally, B. David; Love, John

2011-01-01

The integration of convective weather modeling with trajectory automation for conflict detection, trial planning, direct routing, and auto resolution has uncovered a concept that could help controllers, dispatchers, and pilots identify improved weather routes that result in significant savings in flying time and fuel burn. Trajectory automation continuously and automatically monitors aircraft in flight to find those that could potentially benefit from improved weather reroutes. Controllers, dispatchers, and pilots then evaluate reroute options to assess their suitability given current weather and traffic. In today's operations aircraft fly convective weather avoidance routes that were implemented often hours before aircraft approach the weather and automation does not exist to automatically monitor traffic to find improved weather routes that open up due to changing weather conditions. The automation concept runs in real-time and employs two keysteps. First, a direct routing algorithm automatically identifies flights with large dog legs in their routes and therefore potentially large savings in flying time. These are common - and usually necessary - during convective weather operations and analysis of Fort Worth Center traffic shows many aircraft with short cuts that indicate savings on the order of 10 flying minutes. The second and most critical step is to apply trajectory automation with weather modeling to determine what savings could be achieved by modifying the direct route such that it avoids weather and traffic and is acceptable to controllers and flight crews. Initial analysis of Fort Worth Center traffic suggests a savings of roughly 50% of the direct route savings could be achievable.The core concept is to apply trajectory automation with convective weather modeling in real time to identify a reroute that is free of weather and traffic conflicts and indicates enough time and fuel savings to be considered. The concept is interoperable with today

Cooperative Route Planning for Multiple Aircraft in a Semifree ATC System

Directory of Open Access Journals (Sweden)

Yi Yang

2018-01-01

Full Text Available This paper presents the Semifree Flight theory used in a civil air traffic control (ATC system to improve the capability of the traditional Free Flight mode. The progressiveness and hidden defects of the “Free Flight” model in civil aviation are analysed, and the Semifree Flight ATC system mode is introduced. Moreover, this paper presents the collaborative route planning method, which is the most important method used in the Semifree Flight ATC system. This collaborative route planning method can plan routes for each aircraft (either in flight or just before achieving flight in real time, and the routes can satisfy all the safety constraints. The final numerical simulations verify the correctness and practicability of the Semifree Flight theory and the collaborative route planning method.

DARAL: A Dynamic and Adaptive Routing Algorithm for Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Francisco José Estévez

2016-06-01

Full Text Available The evolution of Smart City projects is pushing researchers and companies to develop more efficient embedded hardware and also more efficient communication technologies. These communication technologies are the focus of this work, presenting a new routing algorithm based on dynamically-allocated sub-networks and node roles. Among these features, our algorithm presents a fast set-up time, a reduced overhead and a hierarchical organization, which allows for the application of complex management techniques. This work presents a routing algorithm based on a dynamically-allocated hierarchical clustering, which uses the link quality indicator as a reference parameter, maximizing the network coverage and minimizing the control message overhead and the convergence time. The present work based its test scenario and analysis in the density measure, considered as a node degree. The routing algorithm is compared with some of the most well known routing algorithms for different scenario densities.

Acquisition of business intelligence from human experience in route planning

Science.gov (United States)

Bello Orgaz, Gema; Barrero, David F.; R-Moreno, María D.; Camacho, David

2015-04-01

The logistic sector raises a number of highly challenging problems. Probably one of the most important ones is the shipping planning, i.e. plan the routes that the shippers have to follow to deliver the goods. In this article, we present an artificial intelligence-based solution that has been designed to help a logistic company to improve its routes planning process. In order to achieve this goal, the solution uses the knowledge acquired by the company drivers to propose optimised routes. Hence, the proposed solution gathers the experience of the drivers, processes it and optimises the delivery process. The solution uses data mining to extract knowledge from the company information systems and prepares it for analysis with a case-based reasoning (CBR) algorithm. The CBR obtains critical business intelligence knowledge from the drivers experience that is needed by the planner. The design of the routes is done by a genetic algorithm that, given the processed information, optimises the routes following several objectives, such as minimise the distance or time. Experimentation shows that the proposed approach is able to find routes that improve, on average, the routes made by the human experts.

Modeling and analysis of rotating plates by using self sensing active constrained layer damping

Energy Technology Data Exchange (ETDEWEB)

Xie, Zheng Chao; Wong, Pak Kin; Chong, Ian Ian [Univ. of Macau, Macau (China)

2012-10-15

This paper proposes a new finite element model for active constrained layer damped (CLD) rotating plate with self sensing technique. Constrained layer damping can effectively reduce the vibration in rotating structures. Unfortunately, most existing research models the rotating structures as beams that are not the case many times. It is meaningful to model the rotating part as plates because of improvements on both the accuracy and the versatility. At the same time, existing research shows that the active constrained layer damping provides a more effective vibration control approach than the passive constrained layer damping. Thus, in this work, a single layer finite element is adopted to model a three layer active constrained layer damped rotating plate. Unlike previous ones, this finite element model treats all three layers as having the both shear and extension strains, so all types of damping are taken into account. Also, the constraining layer is made of piezoelectric material to work as both the self sensing sensor and actuator. Then, a proportional control strategy is implemented to effectively control the displacement of the tip end of the rotating plate. Additionally, a parametric study is conducted to explore the impact of some design parameters on structure's modal characteristics.

Modeling and analysis of rotating plates by using self sensing active constrained layer damping

International Nuclear Information System (INIS)

Xie, Zheng Chao; Wong, Pak Kin; Chong, Ian Ian

2012-01-01

This paper proposes a new finite element model for active constrained layer damped (CLD) rotating plate with self sensing technique. Constrained layer damping can effectively reduce the vibration in rotating structures. Unfortunately, most existing research models the rotating structures as beams that are not the case many times. It is meaningful to model the rotating part as plates because of improvements on both the accuracy and the versatility. At the same time, existing research shows that the active constrained layer damping provides a more effective vibration control approach than the passive constrained layer damping. Thus, in this work, a single layer finite element is adopted to model a three layer active constrained layer damped rotating plate. Unlike previous ones, this finite element model treats all three layers as having the both shear and extension strains, so all types of damping are taken into account. Also, the constraining layer is made of piezoelectric material to work as both the self sensing sensor and actuator. Then, a proportional control strategy is implemented to effectively control the displacement of the tip end of the rotating plate. Additionally, a parametric study is conducted to explore the impact of some design parameters on structure's modal characteristics

Exploring the biological consequences of conformational changes in aspartame models containing constrained analogues of phenylalanine.

Science.gov (United States)

Mollica, Adriano; Mirzaie, Sako; Costante, Roberto; Carradori, Simone; Macedonio, Giorgia; Stefanucci, Azzurra; Dvoracsko, Szabolcs; Novellino, Ettore

2016-12-01

The dipeptide aspartame (Asp-Phe-OMe) is a sweetener widely used in replacement of sucrose by food industry. 2',6'-Dimethyltyrosine (DMT) and 2',6'-dimethylphenylalanine (DMP) are two synthetic phenylalanine-constrained analogues, with a limited freedom in χ-space due to the presence of methyl groups in position 2',6' of the aromatic ring. These residues have shown to increase the activity of opioid peptides, such as endomorphins improving the binding to the opioid receptors. In this work, DMT and DMP have been synthesized following a diketopiperazine-mediated route and the corresponding aspartame derivatives (Asp-DMT-OMe and Asp-DMP-OMe) have been evaluated in vivo and in silico for their activity as synthetic sweeteners.

Vehicle Routing Problem with Time Windows and Simultaneous Delivery and Pick-Up Service Based on MCPSO

Directory of Open Access Journals (Sweden)

Xiaobing Gan

2012-01-01

Full Text Available This paper considers two additional factors of the widely researched vehicle routing problem with time windows (VRPTW. The two factors, which are very common characteristics in realworld, are uncertain number of vehicles and simultaneous delivery and pick-up service. Using minimization of the total transport costs as the objective of the extension VRPTW, a mathematic model is constructed. To solve the problem, an efficient multiswarm cooperative particle swarm optimization (MCPSO algorithm is applied. And a new encoding method is proposed for the extension VRPTW. Finally, comparing with genetic algorithm (GA and particle swarm optimization (PSO algorithm, the MCPSO algorithm performs best for solving this problem.

Optimization of the Costs and the Safety of Maritime Transport by Routing: The use of Currents Forecast in the Routing of Racing Sail Boats as a Prototype of Rout Optimization for Trading Ships

Science.gov (United States)

Theunynck, Denis; Peze, Thierry; Toumazou, Vincent; Zunquin, Gauthier; Cohen, Olivier; Monges, Arnaud

2005-03-01

It is interesting to see whether the model of routing designed for races and great Navy operations could be transferred to commercial navigation and if so, within which framework.Sail boat routing conquered its letters of nobility during great races like the « Route du Rhum » or the transatlantic race « Jacques Vabre ». It is the ultimate stage of the step begun by the Navy at the time of great operations, like D-day (Overlord )June 6, 1944, in Normandy1.Routing is, from the beginning, mainly based on statistical knowledge and weather forecast, but with the recent availability of reliable currents forecast, sail boats routers and/or skippers now have to learn how to use both winds and currents to obtain the best performance, that is to travel between two points in the shortest time possible in acceptable security conditions.Are the currents forecast only useful to racing sail boat ? Of course not, they are a great help to fisherman for whom the knowledge of currents is also the knowledge of sea temperature who indicates the probability of fish presence. They are also used in offshore work to predict the hardness of the sea during operation.A less developed field of application is the route optimization of trading ships. The idea is to optimize the use of currents to increase the relative speed of ships with no augmentation of fuel expense. This new field will require that currents forecasters learn about the specific needs of another type of clients. There is also a need of teaching because the future customers will have to learn how to use the information they will get.At this point, the introduction of the use of currents forecast in racing sail boats routing is only the first step. It is of great interest because it can rely on a high knowledge in routing.The main difference is of course that the wind direction and its force are of greater importance to a sail boat that they are for a trading ship for whom the point of interest will be the fuel consumption

Understanding individual routing behaviour.

Science.gov (United States)

Lima, Antonio; Stanojevic, Rade; Papagiannaki, Dina; Rodriguez, Pablo; González, Marta C

2016-03-01

Knowing how individuals move between places is fundamental to advance our understanding of human mobility (González et al. 2008 Nature 453, 779-782. (doi:10.1038/nature06958)), improve our urban infrastructure (Prato 2009 J. Choice Model. 2, 65-100. (doi:10.1016/S1755-5345(13)70005-8)) and drive the development of transportation systems. Current route-choice models that are used in transportation planning are based on the widely accepted assumption that people follow the minimum cost path (Wardrop 1952 Proc. Inst. Civ. Eng. 1, 325-362. (doi:10.1680/ipeds.1952.11362)), despite little empirical support. Fine-grained location traces collected by smart devices give us today an unprecedented opportunity to learn how citizens organize their travel plans into a set of routes, and how similar behaviour patterns emerge among distinct individual choices. Here we study 92 419 anonymized GPS trajectories describing the movement of personal cars over an 18-month period. We group user trips by origin-destination and we find that most drivers use a small number of routes for their routine journeys, and tend to have a preferred route for frequent trips. In contrast to the cost minimization assumption, we also find that a significant fraction of drivers' routes are not optimal. We present a spatial probability distribution that bounds the route selection space within an ellipse, having the origin and the destination as focal points, characterized by high eccentricity independent of the scale. While individual routing choices are not captured by path optimization, their spatial bounds are similar, even for trips performed by distinct individuals and at various scales. These basic discoveries can inform realistic route-choice models that are not based on optimization, having an impact on several applications, such as infrastructure planning, routing recommendation systems and new mobility solutions. © 2016 The Author(s).

A model to improve the routing performance of Cognitive Radio Wireless Mesh Networks

Directory of Open Access Journals (Sweden)

Lesiba Morries Kola

2017-12-01

Full Text Available The increasing demand for broadband wireless technologies has led to the scarcity, inefficient utilization, and underutilization of the spectrum. The Cognitive Radio (CR technology has emerged as the promising solution which improves the utilization of the spectrum. However, routing is a challenge due to the dynamic nature of the CR networks. The link quality varies in space and time as nodes join and leave the network. The network connectivity is intermittent due to node mobility and the activities of the primary user. The spectrum aware, spectrum agile, and interference aware routing protocols are vital for the sturdiness of the network and efficient utilization of the resources. We propose an interference aware, spectrum aware, and agile extended Weighted Cumulative Expected Transmission Time (xWCETT routing protocol. The protocol integrates the features of the Ad-hoc On-demand Distance Vector (AODV and the weighted cumulative expected transmission time (WCETT routing protocols. The xWCETT was simulated using the Network Simulator 2 and its performance compared with the AODV and the WCETT routing protocols. The xWCETT was evaluated with respect to quality of service related metrics and the results show that it outperformed the AODV and WCETT routing protocols.

Current-State Constrained Filter Bank for Wald Testing of Spacecraft Conjunctions

Science.gov (United States)

Carpenter, J. Russell; Markley, F. Landis

2012-01-01

We propose a filter bank consisting of an ordinary current-state extended Kalman filter, and two similar but constrained filters: one is constrained by a null hypothesis that the miss distance between two conjuncting spacecraft is inside their combined hard body radius at the predicted time of closest approach, and one is constrained by an alternative complementary hypothesis. The unconstrained filter is the basis of an initial screening for close approaches of interest. Once the initial screening detects a possibly risky conjunction, the unconstrained filter also governs measurement editing for all three filters, and predicts the time of closest approach. The constrained filters operate only when conjunctions of interest occur. The computed likelihoods of the innovations of the two constrained filters form a ratio for a Wald sequential probability ratio test. The Wald test guides risk mitigation maneuver decisions based on explicit false alarm and missed detection criteria. Since only current-state Kalman filtering is required to compute the innovations for the likelihood ratio, the present approach does not require the mapping of probability density forward to the time of closest approach. Instead, the hard-body constraint manifold is mapped to the filter update time by applying a sigma-point transformation to a projection function. Although many projectors are available, we choose one based on Lambert-style differential correction of the current-state velocity. We have tested our method using a scenario based on the Magnetospheric Multi-Scale mission, scheduled for launch in late 2014. This mission involves formation flight in highly elliptical orbits of four spinning spacecraft equipped with antennas extending 120 meters tip-to-tip. Eccentricities range from 0.82 to 0.91, and close approaches generally occur in the vicinity of perigee, where rapid changes in geometry may occur. Testing the method using two 12,000-case Monte Carlo simulations, we found the

An Adaptive Tabu Search Heuristic for the Location Routing Pickup and Delivery Problem with Time Windows with a Theater Distribution Application

National Research Council Canada - National Science Library

Burks, Jr, Robert E

2006-01-01

.... The location routing problem (LRP) is an extension of the vehicle routing problem where the solution identifies the optimal location of the depots and provides the vehicle schedules and distribution routes...

High throughput route selection in multi-rate wireless mesh networks

Institute of Scientific and Technical Information of China (English)

WEI Yi-fei; GUO Xiang-li; SONG Mei; SONG Jun-de

2008-01-01

Most existing Ad-hoc routing protocols use the shortest path algorithm with a hop count metric to select paths. It is appropriate in single-rate wireless networks, but has a tendency to select paths containing long-distance links that have low data rates and reduced reliability in multi-rate networks. This article introduces a high throughput routing algorithm utilizing the multi-rate capability and some mesh characteristics in wireless fidelity (WiFi) mesh networks. It uses the medium access control (MAC) transmission time as the routing metric, which is estimated by the information passed up from the physical layer. When the proposed algorithm is adopted, the Ad-hoc on-demand distance vector (AODV) routing can be improved as high throughput AODV (HT-AODV). Simulation results show that HT-AODV is capable of establishing a route that has high data-rate, short end-to-end delay and great network throughput.

Vehicle Routing Problem for Fashion Supply Chains with Cross-Docking

Directory of Open Access Journals (Sweden)

Zhi-Hua Hu

2013-01-01

Full Text Available Cross-docking, as a strategy to reduce lead time and enhance the efficiency of the fashion supply chain, has attracted substantial attention from both the academy and the industry. Cross-docking is a critical part of many fashion and textiles supply chains in practice because it can help to achieve many supply chain strategies such as postponement. We consider a model where there are multiple suppliers and customers in a single cross-docking center. With such a model setting, the issue concerning the coordinated routing between the inbound and outbound routes is much more complex than many traditional vehicle routing problems (VRPs. We formulate the optimal route selection problems from the suppliers to the cross-docking center and from the cross-docking center to the customers as the respective VRPs. Based on the relationships between the suppliers and the customers, we integrate the two VRP models to optimize the overall traveling time, distance, and waiting time at the cross-docking center. In addition, we propose a novel mixed 0/1 integer linear programming model by which the complexity of the problem can be reduced significantly. As demonstrated by the simulation analysis, our proposed model can be solved very efficiently by a commonly used optimization software package.

Multi-objective evacuation routing optimization for toxic cloud releases

International Nuclear Information System (INIS)

Gai, Wen-mei; Deng, Yun-feng; Jiang, Zhong-an; Li, Jing; Du, Yan

2017-01-01

This paper develops a model for assessing the risks associated with the evacuation process in response to potential chemical accidents, based on which a multi-objective evacuation routing model for toxic cloud releases is proposed taking into account that the travel speed on each arc will be affected by disaster extension. The objectives of the evacuation routing model are to minimize travel time and individual evacuation risk along a path respectively. Two heuristic algorithms are proposed to solve the multi-objective evacuation routing model. Simulation results show the effectiveness and feasibility of the model and algorithms presented in this paper. And, the methodology with appropriate modification is suitable for supporting decisions in assessing emergency route selection in other cases (fires, nuclear accidents). - Highlights: • A model for assessing and visualizing the risks is developed. • A multi-objective evacuation routing model is proposed for toxic cloud releases. • A modified Dijkstra algorithm is designed to obtain an solution of the model. • Two heuristic algorithms have been developed as the optimization tool.

Traffic routing for multicomputer networks with virtual cut-through capability

Science.gov (United States)

Kandlur, Dilip D.; Shin, Kang G.

1992-01-01

Consideration is given to the problem of selecting routes for interprocess communication in a network with virtual cut-through capability, while balancing the network load and minimizing the number of times that a message gets buffered. An approach is proposed that formulates the route selection problem as a minimization problem with a link cost function that depends upon the traffic through the link. The form of this cost function is derived using the probability of establishing a virtual cut-through route. The route selection problem is shown to be NP-hard, and an algorithm is developed to incrementally reduce the cost by rerouting the traffic. The performance of this algorithm is exemplified by two network topologies: the hypercube and the C-wrapped hexagonal mesh.

The time dependent Schrodinger equation revisited I: quantum field and classical Hamilton-Jacobi routes to Schrodinger's wave equation

International Nuclear Information System (INIS)

Scully, M O

2008-01-01

The time dependent Schrodinger equation is frequently 'derived' by postulating the energy E → i h-bar (∂/∂t) and momentum p-vector → ( h-bar /i)∇ operator relations. In the present paper we review the quantum field theoretic route to the Schrodinger wave equation which treats time and space as parameters, not operators. Furthermore, we recall that a classical (nonlinear) wave equation can be derived from the classical action via Hamiltonian-Jacobi theory. By requiring the wave equation to be linear we again arrive at the Schrodinger equation, without postulating operator relations. The underlying philosophy is operational: namely 'a particle is what a particle detector detects.' This leads us to a useful physical picture combining the wave (field) and particle paradigms which points the way to the time-dependent Schrodinger equation

Identifying and prioritizing ungulate migration routes for landscape-level conservation

Science.gov (United States)

Sawyer, Hall; Kauffman, Matthew J.; Nielson, Ryan M.; Horne, Jon S.

2009-01-01

As habitat loss and fragmentation increase across ungulate ranges, identifying and prioritizing migration routes for conservation has taken on new urgency. Here we present a general framework using the Brownian bridge movement model (BBMM) that: (1) provides a probabilistic estimate of the migration routes of a sampled population, (2) distinguishes between route segments that function as stopover sites vs. those used primarily as movement corridors, and (3) prioritizes routes for conservation based upon the proportion of the sampled population that uses them. We applied this approach to a migratory mule deer (Odocoileus hemionus) population in a pristine area of southwest Wyoming, USA, where 2000 gas wells and 1609 km of pipelines and roads have been proposed for development. Our analysis clearly delineated where migration routes occurred relative to proposed development and provided guidance for on-the-ground conservation efforts. Mule deer migration routes were characterized by a series of stopover sites where deer spent most of their time, connected by movement corridors through which deer moved quickly. Our findings suggest management strategies that differentiate between stopover sites and movement corridors may be warranted. Because some migration routes were used by more mule deer than others, proportional level of use may provide a reasonable metric by which routes can be prioritized for conservation. The methods we outline should be applicable to a wide range of species that inhabit regions where migration routes are threatened or poorly understood.

A stochastic time-dependent green capacitated vehicle routing and scheduling problem with time window, resiliency and reliability: a case study

Directory of Open Access Journals (Sweden)

Masoud Rabbani

2018-09-01

Full Text Available This paper presents a new multi-objective model for a vehicle routing problem under a stochastic uncertainty. It considers traffic point as an inflection point to deal with the arrival time of vehicles. It aims to minimize the total transportation cost, traffic pollution, customer dissatisfaction and maximizes the reliability of vehicles. Moreover, resiliency factors are included in the model to increase the flexibility of the system and decrease the possible losses that may impose on the system. Due to the NP-hardness of the presented model, a meta-heuristic algorithm, namely Simulated Annealing (SA is developed. Furthermore, a number of sensitivity analyses are provided to validate the effectiveness of the proposed model. Lastly, the foregoing meta-heuristic is compared with GAMS, in which the computational results demonstrate an acceptable performance of the proposed SA.

Comparison of Mucosal, Subcutaneous and Intraperitoneal Routes of Rat Leptospira Infection

Science.gov (United States)

Zilber, Anne-Laure; Belli, Patrick; Grezel, Delphine; Artois, Marc; Kodjo, Angeli; Djelouadji, Zoheira

2016-01-01

Leptospirosis is a zoonosis found worldwide that is caused by a spirochete. The main reservoirs of Leptospira, which presents an asymptomatic infection, are wild rodents, including the brown rat (Rattus norvegicus). Experimental studies of the mechanisms of its renal colonization in rats have previously used an intraperitoneal inoculation route. However, knowledge of rat-rat transmission requires the use of a natural route of inoculation, such as a mucosal or subcutaneous route. We investigated for the first time the effects of subcutaneous and mucosal inoculation routes compared to the reference intraperitoneal route during Leptospira infection in adult rats. Infection characteristics were studied using Leptospira renal isolation, serology, and molecular and histological analyses. Leptospira infection was asymptomatic using each inoculation route, and caused similar antibody production regardless of renal colonization. The observed renal colonization rates were 8 out of 8 rats, 5 out of 8 rats and 1 out of 8 rats for the intraperitoneal, mucosal and subcutaneous inoculation routes, respectively. Thus, among the natural infection routes studied, mucosal inoculation was more efficient for renal colonization associated with urinary excretion than the subcutaneous route and induced a slower-progressing infection than the intraperitoneal route. These results can facilitate understanding of the infection modalities in rats, unlike the epidemiological studies conducted in wild rats. Future studies of other natural inoculation routes in rat models will increase our knowledge of rat-rat disease transmission and allow the investigation of infection kinetics. PMID:27031867

Constraining the noncommutative spectral action via astrophysical observations.

Science.gov (United States)

Nelson, William; Ochoa, Joseph; Sakellariadou, Mairi

2010-09-03

The noncommutative spectral action extends our familiar notion of commutative spaces, using the data encoded in a spectral triple on an almost commutative space. Varying a rather simple action, one can derive all of the standard model of particle physics in this setting, in addition to a modified version of Einstein-Hilbert gravity. In this Letter we use observations of pulsar timings, assuming that no deviation from general relativity has been observed, to constrain the gravitational sector of this theory. While the bounds on the coupling constants remain rather weak, they are comparable to existing bounds on deviations from general relativity in other settings and are likely to be further constrained by future observations.

Label-controlled optical packet routing technologies and applications

DEFF Research Database (Denmark)

Koonen, A.M.J.; Yan, N.; Vegas Olmos, Juan José

2007-01-01

An overview is given of various optical packet labeling techniques. The architecture and technologies are discussed for optical packet routing nodes using orthogonal labeling with optoelectronic label processing, and for nodes using time-serial labeling with all-optical time-serial label processing...

SAFEBIKE: A Bike-sharing Route Recommender with Availability Prediction and Safe Routing

OpenAIRE

Zhong, Weisheng; Chen, Fanglan; Fu, Kaiqun; Lu, Chang-Tien

2017-01-01

This paper presents SAFEBIKE, a novel route recommendation system for bike-sharing service that utilizes station information to infer the number of available bikes in dock and recommend bike routes according to multiple factors such as distance and safety level. The system consists of a station level availability predictor that predicts bikes and docks amount at each station, and an efficient route recommendation service that considers safety and bike/dock availability factors. It targets use...

A heterogeneous fleet vehicle routing model for solving the LPG distribution problem: A case study

International Nuclear Information System (INIS)

Onut, S; Kamber, M R; Altay, G

2014-01-01

Vehicle Routing Problem (VRP) is an important management problem in the field of distribution and logistics. In VRPs, routes from a distribution point to geographically distributed points are designed with minimum cost and considering customer demands. All points should be visited only once and by one vehicle in one route. Total demand in one route should not exceed the capacity of the vehicle that assigned to that route. VRPs are varied due to real life constraints related to vehicle types, number of depots, transportation conditions and time periods, etc. Heterogeneous fleet vehicle routing problem is a kind of VRP that vehicles have different capacity and costs. There are two types of vehicles in our problem. In this study, it is used the real world data and obtained from a company that operates in LPG sector in Turkey. An optimization model is established for planning daily routes and assigned vehicles. The model is solved by GAMS and optimal solution is found in a reasonable time

A heterogeneous fleet vehicle routing model for solving the LPG distribution problem: A case study

Science.gov (United States)

Onut, S.; Kamber, M. R.; Altay, G.

2014-03-01

Vehicle Routing Problem (VRP) is an important management problem in the field of distribution and logistics. In VRPs, routes from a distribution point to geographically distributed points are designed with minimum cost and considering customer demands. All points should be visited only once and by one vehicle in one route. Total demand in one route should not exceed the capacity of the vehicle that assigned to that route. VRPs are varied due to real life constraints related to vehicle types, number of depots, transportation conditions and time periods, etc. Heterogeneous fleet vehicle routing problem is a kind of VRP that vehicles have different capacity and costs. There are two types of vehicles in our problem. In this study, it is used the real world data and obtained from a company that operates in LPG sector in Turkey. An optimization model is established for planning daily routes and assigned vehicles. The model is solved by GAMS and optimal solution is found in a reasonable time.

Development of a Healthy Urban Route Planner for cyclists and pedestrians in Amsterdam

Science.gov (United States)

van der Molen, Michiel; Ligtenberg, Arend; Vreugdenhil, Corne; Steeneveld, Gert-Jan

2017-04-01

Cities are hotspots of air pollution and heat stress, the exposure to which results in nuisance, health risks, cost of medication, reduced labour productivity and sick leave for citizens. Yet the air pollution and heat stress are spatially and temporally unevenly distributed over the city, depending on pollutant emissions, street design and atmospheric turbulent mixing and radiation. This spatiotemporal variation allows pedestrians and bikers to choose alternative routes to minimize their exposure, if the distribution is known. In this project, we develop a route planner for bicyclists and pedestrians for Amsterdam (NL), that proposes routes and departure times based on model simulations of weather and air quality. We use the WRF-Chem atmosphere and air quality model at unprecedented grid spacing of 100-m (Ronda et al, 2015, Super et al, 2016), with an underlying urban canopy model and NOx and PM10 emissions. The emissions by traffic are calculated based on observed traffic intensities and emission factors. An urban land use map will characterize urban density and street configuration to estimate urban heat storage (Attema et al, 2015). WRF-Chem runs will be issued daily for a lead time of 48 hours, resulting in forecast maps of temperature and pollutant concentrations that will be uniquely expressed in a metric that combines both threats. The hourly fields of this metric are provided to the route planner based on the open source routing library pgRouting to identify the more healthy routes on the route network of Amsterdam. The objectives of the healthy urban route planner are to raise awareness of heat and air quality issues in Amsterdam, to provide an innovative adaptation tool for citizens and tourists, to locate the most important bottlenecks in (the exposure to) air pollution and heat stress, and ultimately to test the readiness of the travellers to use the information and adapt the route. We expect to particularly target a group of lung- and cardiovascular

Exploring Constrained Creative Communication

DEFF Research Database (Denmark)

Sørensen, Jannick Kirk

2017-01-01

Creative collaboration via online tools offers a less ‘media rich’ exchange of information between participants than face-to-face collaboration. The participants’ freedom to communicate is restricted in means of communication, and rectified in terms of possibilities offered in the interface. How do...... these constrains influence the creative process and the outcome? In order to isolate the communication problem from the interface- and technology problem, we examine via a design game the creative communication on an open-ended task in a highly constrained setting, a design game. Via an experiment the relation...... between communicative constrains and participants’ perception of dialogue and creativity is examined. Four batches of students preparing for forming semester project groups were conducted and documented. Students were asked to create an unspecified object without any exchange of communication except...

Time-constrained mother and expanding market: emerging model of under-nutrition in India

Directory of Open Access Journals (Sweden)

S. Chaturvedi

2016-07-01

Full Text Available Abstract Background Persistent high levels of under-nutrition in India despite economic growth continue to challenge political leadership and policy makers at the highest level. The present inductive enquiry was conducted to map the perceptions of mothers and other key stakeholders, to identify emerging drivers of childhood under-nutrition. Methods We conducted a multi-centric qualitative investigation in six empowered action group states of India. The study sample included 509 in-depth interviews with mothers of undernourished and normal nourished children, policy makers, district level managers, implementer and facilitators. Sixty six focus group discussions and 72 non-formal interactions were conducted in two rounds with primary caretakers of undernourished children, Anganwadi Workers and Auxiliary Nurse Midwives. Results Based on the perceptions of the mothers and other key stakeholders, a model evolved inductively showing core themes as drivers of under-nutrition. The most forceful emerging themes were: multitasking, time constrained mother with dwindling family support; fragile food security or seasonal food paucity; child targeted market with wide availability and consumption of ready-to-eat market food items; rising non-food expenditure, in the context of rising food prices; inadequate and inappropriate feeding; delayed recognition of under-nutrition and delayed care seeking; and inadequate responsiveness of health care system and Integrated Child Development Services (ICDS. The study emphasized that the persistence of child malnutrition in India is also tied closely to the high workload and consequent time constraint of mothers who are increasingly pursuing income generating activities and enrolled in paid labour force, without robust institutional support for childcare. Conclusion The emerging framework needs to be further tested through mixed and multiple method research approaches to quantify the contribution of time limitation of

Reconfigurable Robust Routing for Mobile Outreach Network

Science.gov (United States)

Lin, Ching-Fang

2010-01-01

The Reconfigurable Robust Routing for Mobile Outreach Network (R3MOO N) provides advanced communications networking technologies suitable for the lunar surface environment and applications. The R3MOON techn ology is based on a detailed concept of operations tailored for luna r surface networks, and includes intelligent routing algorithms and wireless mesh network implementation on AGNC's Coremicro Robots. The product's features include an integrated communication solution inco rporating energy efficiency and disruption-tolerance in a mobile ad h oc network, and a real-time control module to provide researchers an d engineers a convenient tool for reconfiguration, investigation, an d management.

A green vehicle routing problem with customer satisfaction criteria

Science.gov (United States)

Afshar-Bakeshloo, M.; Mehrabi, A.; Safari, H.; Maleki, M.; Jolai, F.

2016-12-01

This paper develops an MILP model, named Satisfactory-Green Vehicle Routing Problem. It consists of routing a heterogeneous fleet of vehicles in order to serve a set of customers within predefined time windows. In this model in addition to the traditional objective of the VRP, both the pollution and customers' satisfaction have been taken into account. Meanwhile, the introduced model prepares an effective dashboard for decision-makers that determines appropriate routes, the best mixed fleet, speed and idle time of vehicles. Additionally, some new factors evaluate the greening of each decision based on three criteria. This model applies piecewise linear functions (PLFs) to linearize a nonlinear fuzzy interval for incorporating customers' satisfaction into other linear objectives. We have presented a mixed integer linear programming formulation for the S-GVRP. This model enriches managerial insights by providing trade-offs between customers' satisfaction, total costs and emission levels. Finally, we have provided a numerical study for showing the applicability of the model.

A Sociability-Based Routing Scheme for Delay-Tolerant Networks

Directory of Open Access Journals (Sweden)

Fabbri Flavio

2011-01-01

Full Text Available The problem of choosing the best forwarders in Delay-Tolerant Networks (DTNs is crucial for minimizing the delay in packet delivery and for keeping the amount of generated traffic under control. In this paper, we introduce sociable routing, a novel routing strategy that selects a subset of optimal forwarders among all the nodes and relies on them for an efficient delivery. The key idea is that of assigning to each network node a time-varying scalar parameter which captures its social behavior in terms of frequency and types of encounters. This sociability concept is widely discussed and mathematically formalized. Simulation results of a DTN of vehicles in urban environment, driven by real mobility traces, and employing sociable routing, is presented. Encouraging results show that sociable routing, compared to other known protocols, achieves a good compromise in terms of delay performance and amount of generated traffic.

mizuRoute version 1: A river network routing tool for a continental domain water resources applications

Science.gov (United States)

Mizukami, Naoki; Clark, Martyn P.; Sampson, Kevin; Nijssen, Bart; Mao, Yixin; McMillan, Hilary; Viger, Roland; Markstrom, Steven; Hay, Lauren E.; Woods, Ross; Arnold, Jeffrey R.; Brekke, Levi D.

2016-01-01

This paper describes the first version of a stand-alone runoff routing tool, mizuRoute. The mizuRoute tool post-processes runoff outputs from any distributed hydrologic model or land surface model to produce spatially distributed streamflow at various spatial scales from headwater basins to continental-wide river systems. The tool can utilize both traditional grid-based river network and vector-based river network data. Both types of river network include river segment lines and the associated drainage basin polygons, but the vector-based river network can represent finer-scale river lines than the grid-based network. Streamflow estimates at any desired location in the river network can be easily extracted from the output of mizuRoute. The routing process is simulated as two separate steps. First, hillslope routing is performed with a gamma-distribution-based unit-hydrograph to transport runoff from a hillslope to a catchment outlet. The second step is river channel routing, which is performed with one of two routing scheme options: (1) a kinematic wave tracking (KWT) routing procedure; and (2) an impulse response function – unit-hydrograph (IRF-UH) routing procedure. The mizuRoute tool also includes scripts (python, NetCDF operators) to pre-process spatial river network data. This paper demonstrates mizuRoute's capabilities to produce spatially distributed streamflow simulations based on river networks from the United States Geological Survey (USGS) Geospatial Fabric (GF) data set in which over 54 000 river segments and their contributing areas are mapped across the contiguous United States (CONUS). A brief analysis of model parameter sensitivity is also provided. The mizuRoute tool can assist model-based water resources assessments including studies of the impacts of climate change on streamflow.

Remotely Sensed Based Lake/Reservoir Routing in Congo River Basin

Science.gov (United States)

Raoufi, R.; Beighley, E.; Lee, H.

2017-12-01

Lake and reservoir dynamics can influence local to regional water cycles but are often not well represented in hydrologic models. One challenge that limits their inclusion in models is the need for detailed storage-discharge behavior that can be further complicated in reservoirs where specific operation rules are employed. Here, the Hillslope River Routing (HRR) model is combined with a remotely sensed based Reservoir Routing (RR) method and applied to the Congo River Basin. Given that topographic data are often continuous over the entire terrestrial surface (i.e., does not differentiate between land and open water), the HRR-RR model integrates topographic derived river networks and catchment boundaries (e.g., HydroSHEDs) with water boundary extents (e.g., Global Lakes and Wetlands Database) to develop the computational framework. The catchments bordering lakes and reservoirs are partitioned into water and land portions, where representative flowpath characteristics are determined and vertical water balance and lateral routings is performed separately on each partition based on applicable process models (e.g., open water evaporation vs. evapotranspiration). To enable reservoir routing, remotely sensed water surface elevations and extents are combined to determine the storage change time series. Based on the available time series, representative storage change patterns are determined. Lake/reservoir routing is performed by combining inflows from the HRR-RR model and the representative storage change patterns to determine outflows. In this study, a suite of storage change patterns derived from remotely sensed measurements are determined representative patterns for wet, dry and average conditions. The HRR-RR model dynamically selects and uses the optimal storage change pattern for the routing process based on these hydrologic conditions. The HRR-RR model results are presented to highlight the importance of lake attenuation/routing in the Congo Basin.

The Dynamic Multi-Period Vehicle Routing Problem

DEFF Research Database (Denmark)

Wen, Min; Cordeau, Jean-Francois; Laporte, Gilbert

This paper considers the Dynamic Multi-Period Vehicle Routing Problem which deals with the distribution of orders from a depot to a set of customers over a multi-period time horizon. Customer orders and their feasible service periods are dynamically revealed over time. The objectives are to minim......This paper considers the Dynamic Multi-Period Vehicle Routing Problem which deals with the distribution of orders from a depot to a set of customers over a multi-period time horizon. Customer orders and their feasible service periods are dynamically revealed over time. The objectives...... are to minimize total travel costs and customer waiting, and to balance the daily workload over the planning horizon. This problem originates from a large distributor operating in Sweden. It is modeled as a mixed integer linear program, and solved by means of a three-phase heuristic that works over a rolling...... planning horizon. The multi-objective aspect of the problem is handled through a scalar technique approach. Computational results show that our solutions improve upon those of the Swedish distributor....

Collaborative en-route and slot allocation algorithm based on fuzzy comprehensive evaluation

Science.gov (United States)

Yang, Shangwen; Guo, Baohua; Xiao, Xuefei; Gao, Haichao

2018-01-01

To allocate the en-routes and slots to the flights with collaborative decision making, a collaborative en-route and slot allocation algorithm based on fuzzy comprehensive evaluation was proposed. Evaluation indexes include flight delay costs, delay time and the number of turning points. Analytic hierarchy process is applied to determining index weights. Remark set for current two flights not yet obtained the en-route and slot in flight schedule is established. Then, fuzzy comprehensive evaluation is performed, and the en-route and slot for the current two flights are determined. Continue selecting the flight not yet obtained an en-route and a slot in flight schedule. Perform fuzzy comprehensive evaluation until all flights have obtained the en-routes and slots. MatlabR2007b was applied to numerical test based on the simulated data of a civil en-route. Test results show that, compared with the traditional strategy of first come first service, the algorithm gains better effect. The effectiveness of the algorithm was verified.

Constraining the magnitude of the largest event in a foreshock-main shock-aftershock sequence

Science.gov (United States)

Shcherbakov, Robert; Zhuang, Jiancang; Ogata, Yosihiko

2018-01-01

Extreme value statistics and Bayesian methods are used to constrain the magnitudes of the largest expected earthquakes in a sequence governed by the parametric time-dependent occurrence rate and frequency-magnitude statistics. The Bayesian predictive distribution for the magnitude of the largest event in a sequence is derived. Two types of sequences are considered, that is, the classical aftershock sequences generated by large main shocks and the aftershocks generated by large foreshocks preceding a main shock. For the former sequences, the early aftershocks during a training time interval are used to constrain the magnitude of the future extreme event during the forecasting time interval. For the latter sequences, the earthquakes preceding the main shock are used to constrain the magnitudes of the subsequent extreme events including the main shock. The analysis is applied retrospectively to past prominent earthquake sequences.

Developing an eco-routing application.

Science.gov (United States)

2014-01-01

The study develops eco-routing algorithms and investigates and quantifies the system-wide impacts of implementing an eco-routing system. Two eco-routing algorithms are developed: one based on vehicle sub-populations (ECO-Subpopulation Feedback Assign...

Diversity in destinations, routes and timing of small adult and sub-adult striped bass Morone saxatilis on their southward autumn migration

Science.gov (United States)

Mather, Martha E.; Finn, John T.; Pautzke, Sarah M.; Fox, Dewayne A.; Savoy, Tom; Brundage, Harold M.; Deegan, Linda A.; Muth, Robert M.

2010-01-01

Almost three-quarters of the 46 young adult and sub-adult striped bass Morone saxatilis that were acoustically tagged in Plum Island Estuary, Massachusetts, U.S.A., in the summer of 2006 were detected in one or more southern coastal arrays during their autumn migration. On the basis of the trajectories along which these M. saxatilis moved from feeding to overwintering areas, three migratory groups emerged. After leaving Plum Island Estuary, about half of the fish were detected only in a mid-latitude array, Long Island Sound. The other half of the tagged fish were detected during autumn and winter in a more southern array, the Delaware Estuary. This latter group of fish may have used two routes. Some travelled to the Delaware Estuary through Long Island Sound while other fish may have taken a second, more direct, coastal route that did not include Long Island Sound. Consequently, a seemingly homogeneous group of fish tagged at the same time in the same non-natal feeding location exhibited a diversity of southward movement patterns that could affect population-level processes. These three groups that differed in overwintering location and migration route could be movement contingents with migratory connectivity.

Optical slotted circuit switched network: a bandwidth efficient alternative to wavelength-routed network

Science.gov (United States)

Li, Yan; Collier, Martin

2007-11-01

Wavelength-routed networks have received enormous attention due to the fact that they are relatively simple to implement and implicitly offer Quality of Service (QoS) guarantees. However, they suffer from a bandwidth inefficiency problem and require complex Routing and Wavelength Assignment (RWA). Most attempts to address the above issues exploit the joint use of WDM and TDM technologies. The resultant TDM-based wavelength-routed networks partition the wavelength bandwidth into fixed-length time slots organized as a fixed-length frame. Multiple connections can thus time-share a wavelength and the grooming of their traffic leads to better bandwidth utilization. The capability of switching in both wavelength and time domains in such networks also mitigates the RWA problem. However, TMD-based wavelength-routed networks work in synchronous mode and strict synchronization among all network nodes is required. Global synchronization for all-optical networks which operate at extremely high speed is technically challenging, and deploying an optical synchronizer for each wavelength involves considerable cost. An Optical Slotted Circuit Switching (OSCS) architecture is proposed in this paper. In an OSCS network, slotted circuits are created to better utilize the wavelength bandwidth than in classic wavelength-routed networks. The operation of the protocol is such as to avoid the need for global synchronization required by TDM-based wavelength-routed networks.

Maglev guideway route alignment and right-of-way requirements

Science.gov (United States)

Carlton, S.; Andriola, T.

1992-12-01

The use of existing rights-of-way (ROW) is assessed for maglev systems by estimating trip times and land acquisition requirements for potential maglev corridors while meeting passenger comfort limits. Right-of-way excursions improve trip time but incur a cost for purchasing land. The final report documents findings of the eight tasks in establishing right-of-way feasibility by examining three city-pair corridors in detail and developing an approximation method for estimating route length and travel times in 20 additional city-pair corridor portions and 21 new corridors. The use of routes independent of existing railroad or highway right-of-way have trip time advantages and significantly reduce the need for aggressive guideway geometries on intercity corridors. Selection of the appropriate alignment is determined by many corridor specific issues. Use of existing intercity rights-of-way may be appropriate for parts of routes on a corridor-specific basis and for urban penetration where vehicle speeds are likely to be reduced by policy due to noise and safety considerations, and where land acquisition costs are high. Detailed aspects of available rights-of-way, land acquisition costs, geotechnical issues, land use, and population centers must be examined in more detail on a specific corridor basis before the proper or best maglev alignment can be chosen.

Robustness of airline route networks

Science.gov (United States)

Lordan, Oriol; Sallan, Jose M.; Escorihuela, Nuria; Gonzalez-Prieto, David

2016-03-01

Airlines shape their route network by defining their routes through supply and demand considerations, paying little attention to network performance indicators, such as network robustness. However, the collapse of an airline network can produce high financial costs for the airline and all its geographical area of influence. The aim of this study is to analyze the topology and robustness of the network route of airlines following Low Cost Carriers (LCCs) and Full Service Carriers (FSCs) business models. Results show that FSC hubs are more central than LCC bases in their route network. As a result, LCC route networks are more robust than FSC networks.

The effect of stimulus intensity on response time and accuracy in dynamic, temporally constrained environments.

Science.gov (United States)

Causer, J; McRobert, A P; Williams, A M

2013-10-01

The ability to make accurate judgments and execute effective skilled movements under severe temporal constraints are fundamental to elite performance in a number of domains including sport, military combat, law enforcement, and medicine. In two experiments, we examine the effect of stimulus strength on response time and accuracy in a temporally constrained, real-world, decision-making task. Specifically, we examine the effect of low stimulus intensity (black) and high stimulus intensity (sequin) uniform designs, worn by teammates, to determine the effect of stimulus strength on the ability of soccer players to make rapid and accurate responses. In both field- and laboratory-based scenarios, professional soccer players viewed developing patterns of play and were required to make a penetrative pass to an attacking player. Significant differences in response accuracy between uniform designs were reported in laboratory- and field-based experiments. Response accuracy was significantly higher in the sequin compared with the black uniform condition. Response times only differed between uniform designs in the laboratory-based experiment. These findings extend the literature into a real-world environment and have significant implications for the design of clothing wear in a number of domains. © 2012 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Effects of a Cooperative Learning Strategy on the Effectiveness of Physical Fitness Teaching and Constraining Factors

Directory of Open Access Journals (Sweden)

Tsui-Er Lee

2014-01-01

Full Text Available The effects of cooperative learning and traditional learning on the effectiveness and constraining factors of physical fitness teaching under various teaching conditions were studied. Sixty female students in Grades 7–8 were sampled to evaluate their learning of health and physical education (PE according to the curriculum for Grades 1–9 in Taiwan. The data were quantitatively and qualitatively collected and analyzed. The overall physical fitness of the cooperative learning group exhibited substantial progress between the pretest and posttest, in which the differences in the sit-and-reach and bent-knee sit-up exercises achieved statistical significance. The performance of the cooperative learning group in the bent-knee sit-up and 800 m running exercises far exceeded that of the traditional learning group. Our qualitative data indicated that the number of people grouped before a cooperative learning session, effective administrative support, comprehensive teaching preparation, media reinforcement, constant feedback and introspection regarding cooperative learning strategies, and heterogeneous grouping are constraining factors for teaching PE by using cooperative learning strategies. Cooperative learning is considered an effective route for attaining physical fitness among students. PE teachers should consider providing extrinsic motivation for developing learning effectiveness.

CROATIAN AND INTERNATIONAL COPPER AND SALT ROUTES IN THE PART OF EUROPE

Directory of Open Access Journals (Sweden)

Berislav Šebečić

2001-12-01

Full Text Available Middle Ages as well as in modern times. Those were caravan and cart routes and navigable river routes adapted to the possibilities of the then traffic. The iinportance of the copper and salt trade has been fin pointed out. From ancient times up until the mid-nineteenth century copper was pro-duced from copper ores in Rude near Samobor and from the mid-nine-teenth century until the beginning of the World War I mostly in Trgovi and Bešinac in Trgovska gora. The main copper trade was carried out from Rude over Dubovac (Karlovac, later on and Vrbovsko to Bakar and later on to Rijeka. I have named that the most important Croatian copper route. Intense intenational trade through Croatia that took place at the late fifteenth and in the course of the sixteenth centuries was a combination of river and cart traffic from the former foundries iu Bans-ka Bistrica (in Slovakia todayover Budim, Zagreb, Dubovac and Mod-ruš to Senj from where cargo was loaded on the ships sailing to Venice and all over the world. That route I have named the intenational copper route. Sea-salt was transported from the Adriatic saltvorks towards inland areas (Croatia salts routes; rock-salt was imported from Hungarian salt-works (todaj in ihe western Roumania and from the Tuzla salts works to the northern part of Croatia (International salt routes (the paper is published in Croatian.

B-iTRS: A Bio-Inspired Trusted Routing Scheme for Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Mingchuan Zhang

2015-01-01

Full Text Available In WSNs, routing algorithms need to handle dynamical changes of network topology, extra overhead, energy saving, and other requirements. Therefore, routing in WSNs is an extremely interesting and challenging issue. In this paper, we present a novel bio-inspired trusted routing scheme (B-iTRS based on ant colony optimization (ACO and Physarum autonomic optimization (PAO. For trust assessment, B-iTRS monitors neighbors’ behavior in real time, receives feedback from Sink, and then assesses neighbors’ trusts based on the acquired information. For routing scheme, each node finds routes to the Sink based on ACO and PAO. In the process of path finding, B-iTRS senses the load and trust value of each node and then calculates the link load and link trust of the found routes to support the route selection. Moreover, B-iTRS also assesses the route based on PAO to maintain the route table. Simulation results show how B-iTRS can achieve the effective performance compared to existing state-of-the-art algorithms.

Hydrologic and hydraulic flood forecasting constrained by remote sensing data

Science.gov (United States)

Li, Y.; Grimaldi, S.; Pauwels, V. R. N.; Walker, J. P.; Wright, A. J.

2017-12-01

Flooding is one of the most destructive natural disasters, resulting in many deaths and billions of dollars of damages each year. An indispensable tool to mitigate the effect of floods is to provide accurate and timely forecasts. An operational flood forecasting system typically consists of a hydrologic model, converting rainfall data into flood volumes entering the river system, and a hydraulic model, converting these flood volumes into water levels and flood extents. Such a system is prone to various sources of uncertainties from the initial conditions, meteorological forcing, topographic data, model parameters and model structure. To reduce those uncertainties, current forecasting systems are typically calibrated and/or updated using ground-based streamflow measurements, and such applications are limited to well-gauged areas. The recent increasing availability of spatially distributed remote sensing (RS) data offers new opportunities to improve flood forecasting skill. Based on an Australian case study, this presentation will discuss the use of 1) RS soil moisture to constrain a hydrologic model, and 2) RS flood extent and level to constrain a hydraulic model.The GRKAL hydrological model is calibrated through a joint calibration scheme using both ground-based streamflow and RS soil moisture observations. A lag-aware data assimilation approach is tested through a set of synthetic experiments to integrate RS soil moisture to constrain the streamflow forecasting in real-time.The hydraulic model is LISFLOOD-FP which solves the 2-dimensional inertial approximation of the Shallow Water Equations. Gauged water level time series and RS-derived flood extent and levels are used to apply a multi-objective calibration protocol. The effectiveness with which each data source or combination of data sources constrained the parameter space will be discussed.

Route around real time

International Nuclear Information System (INIS)

Terrier, Francois

1996-01-01

The greater and greater autonomy and complexity asked to the control and command systems lead to work on introducing techniques such as Artificial Intelligence or concurrent object programming in industrial applications. However, while the critical feature of these systems impose to control the dynamics of the proposed solutions, their complexity often imposes a high adaptability to a partially modelled environment. The studies presented start from low level control and command systems to more complex applications at higher levels, such as 'supervision systems'. Techniques such as temporal reasoning and uncertainty management are proposed for the first studies, while the second are tackled with programming techniques based on the real time object paradigm. The outcomes of this itinerary crystallize on the ACCORD project which targets to manage - on the whole life cycle of a real time application - these two problematics, sometimes antagonistic: control of the dynamics and adaptivity. (author) [fr

Constrained generalized mechanics. The second-order case

International Nuclear Information System (INIS)

Tapia, V.

1985-01-01

The Dirac formalism for constrained systems is developed for systems described by a Lagrangian depending on up to a second-order time derivatives of the generalized co-ordinates (accelerations). It turns out that for a Lagrangian of this kind differing by a total time derivative from a Lagrangian depending on only up to first-order time-derivatives of the generalized co-ordinates (velocities), both classical mechanics at the Lagrangian level are the same; at the Hamiltonian level the two classical mechanics differ conceptually even when the solutions to both sets of Hamiltonian equations of motion are the same

Feature and Pose Constrained Visual Aided Inertial Navigation for Computationally Constrained Aerial Vehicles

Science.gov (United States)

Williams, Brian; Hudson, Nicolas; Tweddle, Brent; Brockers, Roland; Matthies, Larry

2011-01-01

A Feature and Pose Constrained Extended Kalman Filter (FPC-EKF) is developed for highly dynamic computationally constrained micro aerial vehicles. Vehicle localization is achieved using only a low performance inertial measurement unit and a single camera. The FPC-EKF framework augments the vehicle's state with both previous vehicle poses and critical environmental features, including vertical edges. This filter framework efficiently incorporates measurements from hundreds of opportunistic visual features to constrain the motion estimate, while allowing navigating and sustained tracking with respect to a few persistent features. In addition, vertical features in the environment are opportunistically used to provide global attitude references. Accurate pose estimation is demonstrated on a sequence including fast traversing, where visual features enter and exit the field-of-view quickly, as well as hover and ingress maneuvers where drift free navigation is achieved with respect to the environment.

Computer-Assisted Periodical Routing and Renewal Audit

Science.gov (United States)

Yerkey, A. Neil

1973-01-01

A computer-assisted periodical control system was designed to reduce clerical time required to maintain records in three areas: renewal audit, routing, and records-keeping. The renewal audit features are unusual and are described in detail. (3 references) (Author/DH)

An Airlift Hub-and-Spoke Location-Routing Model with Time Windows: Case Study of the CONUS-to-Korea Airlift Problem

Science.gov (United States)

1998-03-01

a point of embarkation to a point of debarkation. This study develops an alternative hub-and-spoke combined location-routing integer linear...programming prototype model, and uses this model to determine what advantages a hub-and-spoke system offers, and in which scenarios it is better-suited than the...extension on the following works: the hierarchical model of Perl and Daskin (1983), time windows features of Chan (1991), combining subtour-breaking and range

Clique inequalities applied to the vehicle routing problem with time windows

DEFF Research Database (Denmark)

Spoorendonk, Simon; Desaulniers, Guy

2010-01-01

criterion applied in the pricing algorithm, which is a labeling algorithm for solving resource-constrained elementary shortest path problems. The idea of using cutting planes defined on the master problem variables for the VRPTW has been recently developed: Chva´tal-Gomory rank-1 cuts were applied. However......, to our knowledge, this is a first attempt at incorporating for the VRPTW a set of valid inequalities specialized for the set partitioning polytope. Computational results show that the use of clique inequalities improves the lower bound at the root node of the search tree and reduces the number of nodes...

An overview of smart grid routing algorithms

Science.gov (United States)

Wang, Junsheng; OU, Qinghai; Shen, Haijuan

2017-08-01

This paper summarizes the typical routing algorithm in smart grid by analyzing the communication business and communication requirements of intelligent grid. Mainly from the two kinds of routing algorithm is analyzed, namely clustering routing algorithm and routing algorithm, analyzed the advantages and disadvantages of two kinds of typical routing algorithm in routing algorithm and applicability.

Traffic Route Guidance using Feedback of Predicted Travel Times : Improving Travel Times in the Berlin Traffic Network

OpenAIRE

Bergsten, Arvid; Zetterberg, Daniel

2008-01-01

Traffic congestions constitute a problem in many large cities. Congestions can be handled by reducing the network demand, expanding the infrastructure, or by utilizing the road network more efficiently. This master thesis presents a methodology for route guidance, based on automatic feedback control from the current traffic situation. Through variable direction signs or individual in-car devices, all vehicles with a certain origin and destination (which are both normally intermediate) are gui...

Exact route-length formulas and a storage location assignment heuristic for picker-to-parts warehouses

NARCIS (Netherlands)

Dijkstra, Arjan; Roodbergen, Kees Jan

2017-01-01

Order picking is one of the most time-critical processes in warehouses. We focus on the combined effects of routing methods and storage location assignment on process performance. We present exact formulas for the average route length under any storage location assignment for four common routing

Choosing health, constrained choices.

Science.gov (United States)

Chee Khoon Chan

2009-12-01

In parallel with the neo-liberal retrenchment of the welfarist state, an increasing emphasis on the responsibility of individuals in managing their own affairs and their well-being has been evident. In the health arena for instance, this was a major theme permeating the UK government's White Paper Choosing Health: Making Healthy Choices Easier (2004), which appealed to an ethos of autonomy and self-actualization through activity and consumption which merited esteem. As a counterpoint to this growing trend of informed responsibilization, constrained choices (constrained agency) provides a useful framework for a judicious balance and sense of proportion between an individual behavioural focus and a focus on societal, systemic, and structural determinants of health and well-being. Constrained choices is also a conceptual bridge between responsibilization and population health which could be further developed within an integrative biosocial perspective one might refer to as the social ecology of health and disease.

Discrete Optimization Model for Vehicle Routing Problem with Scheduling Side Cosntraints

Science.gov (United States)

Juliandri, Dedy; Mawengkang, Herman; Bu'ulolo, F.

2018-01-01

Vehicle Routing Problem (VRP) is an important element of many logistic systems which involve routing and scheduling of vehicles from a depot to a set of customers node. This is a hard combinatorial optimization problem with the objective to find an optimal set of routes used by a fleet of vehicles to serve the demands a set of customers It is required that these vehicles return to the depot after serving customers’ demand. The problem incorporates time windows, fleet and driver scheduling, pick-up and delivery in the planning horizon. The goal is to determine the scheduling of fleet and driver and routing policies of the vehicles. The objective is to minimize the overall costs of all routes over the planning horizon. We model the problem as a linear mixed integer program. We develop a combination of heuristics and exact method for solving the model.

Performance Evaluation of AODV Routing Protocol in VANET with NS2

Directory of Open Access Journals (Sweden)

Divya Rathi

2017-03-01

Full Text Available In intelligent transportation systems, the collaboration between vehicles and the road side units is essential to bring these systems to realization. The emerging Vehicular Ad Hoc Network (VANET is becoming more and more important as it provides intelligent transportation application, comfort, safety, entertainment for people in vehicles. In order to provide stable routes and to get good performance in VANET, there is a need of proper routing protocols must be designed. In this paper, we are working with the very well-known ad-hoc on-demand distance vector (AODV routing protocol. The existing Routing protocol AODV-L which is based on the Link expiration time is extended to propose a more reliable AODV-AD which is based on multichannel MAC protocol. For the performance evaluation of routing protocols, a simulation tool ‘NS2’ has been used. Simulation results show that the proposed AODV-AD protocol can achieves better performances in forms of high Route stability, Packet Delivery ratio and packet loss rate than traditional AODV-L and traditional AODV.

Lagrangian formalism for constrained systems. 2. Gauge symmetries

International Nuclear Information System (INIS)

Pyatov, P.N.

1990-01-01

Using the Lagrangian formalism for constrained systems all gauge symmetries peculiar for a given Lagrangian system and in establishing the relation between them and the constraints are constructed. Besides, the question about the possible dependence of gauge transformations on accelerations and other higher order time derivatives of coordinates is clarified. 14 refs

Southern states' routing agency report

International Nuclear Information System (INIS)

1989-02-01

The Southern states' routing agency report is a compendium of 16-southern states' routing programs relative to the transportation of high-level radioactive materials. The report identifies the state-designated routing agencies as defined under 49 Code of Federal Regulations (CFR) Part 171 and provides a reference to the source ad scope of the agencies' rulemaking authority. Additionally, the state agency and contact designated by the state's governor to receive advance notification and shipment routing information under 10 CFR Parts 71 and 73 are also listed

Southern States' Routing Agency Report

International Nuclear Information System (INIS)

1990-03-01

The Southern States' Routing Agency Report is a compendium of 16-southern states' routing program for the transportation of high-level radioactive materials. The report identifies the state-designated routing agencies as defined under 49 Code of Federal Regulations (CFR) Part 171 and provides a reference to the source and scope of the agencies' rulemaking authority. Additionally, the state agency and contact designated by the state's governor to receive advance notification and shipment routing information under 10 CFR Parts 71 and 73 are also listed

Routing in Networks with Random Topologies

Science.gov (United States)

Bambos, Nicholas

1997-01-01

We examine the problems of routing and server assignment in networks with random connectivities. In such a network the basic topology is fixed, but during each time slot and for each of tis input queues, each server (node) is either connected to or disconnected from each of its queues with some probability.

Constraining neutrinoless double beta decay

International Nuclear Information System (INIS)

Dorame, L.; Meloni, D.; Morisi, S.; Peinado, E.; Valle, J.W.F.

2012-01-01

A class of discrete flavor-symmetry-based models predicts constrained neutrino mass matrix schemes that lead to specific neutrino mass sum-rules (MSR). We show how these theories may constrain the absolute scale of neutrino mass, leading in most of the cases to a lower bound on the neutrinoless double beta decay effective amplitude.

Load Balancing Routing with Bounded Stretch

Directory of Open Access Journals (Sweden)

Chen Siyuan

2010-01-01

Full Text Available Routing in wireless networks has been heavily studied in the last decade. Many routing protocols are based on classic shortest path algorithms. However, shortest path-based routing protocols suffer from uneven load distribution in the network, such as crowed center effect where the center nodes have more load than the nodes in the periphery. Aiming to balance the load, we propose a novel routing method, called Circular Sailing Routing (CSR, which can distribute the traffic more evenly in the network. The proposed method first maps the network onto a sphere via a simple stereographic projection, and then the route decision is made by a newly defined "circular distance" on the sphere instead of the Euclidean distance in the plane. We theoretically prove that for a network, the distance traveled by the packets using CSR is no more than a small constant factor of the minimum (the distance of the shortest path. We also extend CSR to a localized version, Localized CSR, by modifying greedy routing without any additional communication overhead. In addition, we investigate how to design CSR routing for 3D networks. For all proposed methods, we conduct extensive simulations to study their performances and compare them with global shortest path routing or greedy routing in 2D and 3D wireless networks.

HotpathVM: An Effective JIT for Resource-constrained Devices

DEFF Research Database (Denmark)

Gal, Andreas; Franz, Michael; Probst, Christian

2006-01-01

We present a just-in-time compiler for a Java VM that is small enough to fit on resource-constrained devices, yet surprisingly effective. Our system dynamically identifies traces of frequently executed bytecode instructions (which may span several basic blocks across several methods) and compiles...

Multi-terminal pipe routing by Steiner minimal tree and particle swarm optimisation

Science.gov (United States)

Liu, Qiang; Wang, Chengen

2012-08-01

Computer-aided design of pipe routing is of fundamental importance for complex equipments' developments. In this article, non-rectilinear branch pipe routing with multiple terminals that can be formulated as a Euclidean Steiner Minimal Tree with Obstacles (ESMTO) problem is studied in the context of an aeroengine-integrated design engineering. Unlike the traditional methods that connect pipe terminals sequentially, this article presents a new branch pipe routing algorithm based on the Steiner tree theory. The article begins with a new algorithm for solving the ESMTO problem by using particle swarm optimisation (PSO), and then extends the method to the surface cases by using geodesics to meet the requirements of routing non-rectilinear pipes on the surfaces of aeroengines. Subsequently, the adaptive region strategy and the basic visibility graph method are adopted to increase the computation efficiency. Numeral computations show that the proposed routing algorithm can find satisfactory routing layouts while running in polynomial time.

A dynamic routing strategy with limited buffer on scale-free network

Science.gov (United States)

Wang, Yufei; Liu, Feng

2016-04-01

In this paper, we propose an integrated routing strategy based on global static topology information and local dynamic data packet queue lengths to improve the transmission efficiency of scale-free networks. The proposed routing strategy is a combination of a global static routing strategy (based on the shortest path algorithm) and local dynamic queue length management, in which, instead of using an infinite buffer, the queue length of each node i in the proposed routing strategy is limited by a critical queue length Qic. When the network traffic is lower and the queue length of each node i is shorter than its critical queue length Qic, it forwards packets according to the global routing table. With increasing network traffic, when the buffers of the nodes with higher degree are full, they do not receive packets due to their limited buffers and the packets have to be delivered to the nodes with lower degree. The global static routing strategy can shorten the transmission time that it takes a packet to reach its destination, and the local limited queue length can balance the network traffic. The optimal critical queue lengths of nodes have been analysed. Simulation results show that the proposed routing strategy can get better performance than that of the global static strategy based on topology, and almost the same performance as that of the global dynamic routing strategy with less complexity.

Energy Reduction Multipath Routing Protocol for MANET Using Recoil Technique

Directory of Open Access Journals (Sweden)

Rakesh Kumar Sahu

2018-04-01

Full Text Available In Mobile Ad-hoc networks (MANET, power conservation and utilization is an acute problem and has received significant attention from academics and industry in recent years. Nodes in MANET function on battery power, which is a rare and limited energy resource. Hence, its conservation and utilization should be done judiciously for the effective functioning of the network. In this paper, a novel protocol namely Energy Reduction Multipath Routing Protocol for MANET using Recoil Technique (AOMDV-ER is proposed, which conserves the energy along with optimal network lifetime, routing overhead, packet delivery ratio and throughput. It performs better than any other AODV based algorithms, as in AOMDV-ER the nodes transmit packets to their destination smartly by using a varying recoil off time technique based on their geographical location. This concept reduces the number of transmissions, which results in the improvement of network lifetime. In addition, the local level route maintenance reduces the additional routing overhead. Lastly, the prediction based link lifetime of each node is estimated which helps in reducing the packet loss in the network. This protocol has three subparts: an optimal route discovery algorithm amalgamation with the residual energy and distance mechanism; a coordinated recoiled nodes algorithm which eliminates the number of transmissions in order to reduces the data redundancy, traffic redundant, routing overhead, end to end delay and enhance the network lifetime; and a last link reckoning and route maintenance algorithm to improve the packet delivery ratio and link stability in the network. The experimental results show that the AOMDV-ER protocol save at least 16% energy consumption, 12% reduction in routing overhead, significant achievement in network lifetime and packet delivery ratio than Ad hoc on demand multipath distance vector routing protocol (AOMDV, Ad hoc on demand multipath distance vector routing protocol life

Guidelines for selecting preferred highway routes for highway-route-controlled quantity shipments of radioactive materials

International Nuclear Information System (INIS)

1989-01-01

The document presents guidelines for use by State officials in selecting preferred routes for highway route controlled quantity shipments of radioactive materials. A methodology for analyzing and comparing safety factors of alternative routes is described. Technical information on the impacts of radioactive material transportation needed to apply the methodology is also presented. Application of the methodology will identify the route (or set of routes) that minimizes the radiological impacts from shipments of these radioactive materials within a given State. Emphasis in the document is on practical application of the methodology. Some details of the derivation of the methods and data are presented in the appendices. All references in the body of the report can be found listed in the Bibliography (Appendix F)

Change Semantic Constrained Online Data Cleaning Method for Real-Time Observational Data Stream

Science.gov (United States)

Ding, Yulin; Lin, Hui; Li, Rongrong

2016-06-01

to large estimation error. In order to achieve the best generalization error, it is an important challenge for the data cleaning methodology to be able to characterize the behavior of data stream distributions and adaptively update a model to include new information and remove old information. However, the complicated data changing property invalidates traditional data cleaning methods, which rely on the assumption of a stationary data distribution, and drives the need for more dynamic and adaptive online data cleaning methods. To overcome these shortcomings, this paper presents a change semantics constrained online filtering method for real-time observational data. Based on the principle that the filter parameter should vary in accordance to the data change patterns, this paper embeds semantic description, which quantitatively depicts the change patterns in the data distribution to self-adapt the filter parameter automatically. Real-time observational water level data streams of different precipitation scenarios are selected for testing. Experimental results prove that by means of this method, more accurate and reliable water level information can be available, which is prior to scientific and prompt flood assessment and decision-making.

CHANGE SEMANTIC CONSTRAINED ONLINE DATA CLEANING METHOD FOR REAL-TIME OBSERVATIONAL DATA STREAM

Directory of Open Access Journals (Sweden)

Y. Ding

2016-06-01

data streams, which may led to large estimation error. In order to achieve the best generalization error, it is an important challenge for the data cleaning methodology to be able to characterize the behavior of data stream distributions and adaptively update a model to include new information and remove old information. However, the complicated data changing property invalidates traditional data cleaning methods, which rely on the assumption of a stationary data distribution, and drives the need for more dynamic and adaptive online data cleaning methods. To overcome these shortcomings, this paper presents a change semantics constrained online filtering method for real-time observational data. Based on the principle that the filter parameter should vary in accordance to the data change patterns, this paper embeds semantic description, which quantitatively depicts the change patterns in the data distribution to self-adapt the filter parameter automatically. Real-time observational water level data streams of different precipitation scenarios are selected for testing. Experimental results prove that by means of this method, more accurate and reliable water level information can be available, which is prior to scientific and prompt flood assessment and decision-making.

Performance Improvements and Congestion Reduction for Routing-based Synthesis for Digital Microfluidic Biochips

DEFF Research Database (Denmark)

Windh, Skyler; Phung, Calvin; Grissom, Daniel T.

2017-01-01

Routing-based synthesis for digital microfluidic biochips yields faster assay execution times compared to module-based synthesis. We show that routing-based synthesis can lead to deadlocks and livelocks in specific cases, and that dynamically detecting them and adjusting the probabilities...

Cluster Based Hierarchical Routing Protocol for Wireless Sensor Network

OpenAIRE

Rashed, Md. Golam; Kabir, M. Hasnat; Rahim, Muhammad Sajjadur; Ullah, Shaikh Enayet

2012-01-01

The efficient use of energy source in a sensor node is most desirable criteria for prolong the life time of wireless sensor network. In this paper, we propose a two layer hierarchical routing protocol called Cluster Based Hierarchical Routing Protocol (CBHRP). We introduce a new concept called head-set, consists of one active cluster head and some other associate cluster heads within a cluster. The head-set members are responsible for control and management of the network. Results show that t...

Biodistribution of radiolabelled human dendritic cells injected by various routes

International Nuclear Information System (INIS)

Quillien, Veronique; Moisan, Annick; Carsin, Andre; Lesimple, Thierry; Lefeuvre, Claudia; Bertho, Nicolas; Devillers, Anne; Toujas, Louis; Adamski, Henri; Leberre, Claudine

2005-01-01

The purpose of this study was to investigate the biodistribution of mature dendritic cells (DCs) injected by various routes, during a cell therapy protocol. In the context of a vaccine therapy protocol for melanoma, DCs matured with Ribomunyl and interferon-gamma were labelled with 111 In-oxine and injected into eight patients along various routes: afferent lymphatic vessel (IL) (4 times), lymph node (IN) (5 times) and intradermally (ID) (6 times). Scintigraphic investigations showed that the IL route allowed localisation of 80% of injected radioactivity in eight to ten nodes. In three cases of IN injection, the entire radioactivity stagnated in the injected nodes, while in two cases, migration to adjacent nodes was observed. This migration was detected rapidly after injection, as with IL injections, suggesting that passive transport occurred along the physiological lymphatic pathways. In two of the six ID injections, 1-2% of injected radioactivity reached a proximal lymph node. Migration was detectable in the first hour, but increased considerably after 24 h, suggesting an active migration mechanism. In both of the aforementioned cases, DCs were strongly CCR7-positive, but this feature was not a sufficient condition for effective migration. In comparison with DCs matured with TNF-α, IL-1β, IL-6 and PGE2, our DCs showed a weaker in vitro migratory response to CCL21, despite comparable CCR7 expression, and higher allostimulatory and TH1 polarisation capacities. The IL route allowed reproducible administration of specified numbers of DCs. The IN route sometimes yielded fairly similar results, but not reproducibly. Lastly, we showed that DCs matured without PGE2 that have in vitro TH1 polarisation capacities can migrate to lymph nodes after ID injection. (orig.)

Strategies for Selecting Routes through Real-World Environments: Relative Topography, Initial Route Straightness, and Cardinal Direction.

Directory of Open Access Journals (Sweden)

Tad T Brunyé

Full Text Available Previous research has demonstrated that route planners use several reliable strategies for selecting between alternate routes. Strategies include selecting straight rather than winding routes leaving an origin, selecting generally south- rather than north-going routes, and selecting routes that avoid traversal of complex topography. The contribution of this paper is characterizing the relative influence and potential interactions of these strategies. We also examine whether individual differences would predict any strategy reliance. Results showed evidence for independent and additive influences of all three strategies, with a strong influence of topography and initial segment straightness, and relatively weak influence of cardinal direction. Additively, routes were also disproportionately selected when they traversed relatively flat regions, had relatively straight initial segments, and went generally south rather than north. Two individual differences, extraversion and sense of direction, predicted the extent of some effects. Under real-world conditions navigators indeed consider a route's initial straightness, cardinal direction, and topography, but these cues differ in relative influence and vary in their application across individuals.

Deterministic Greedy Routing with Guaranteed Delivery in 3D Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Su Xia

2014-05-01

Full Text Available With both computational complexity and storage space bounded by a small constant, greedy routing is recognized as an appealing approach to support scalable routing in wireless sensor networks. However, significant challenges have been encountered in extending greedy routing from 2D to 3D space. In this research, we develop decentralized solutions to achieve greedy routing in 3D sensor networks. Our proposed approach is based on a unit tetrahedron cell (UTC mesh structure. We propose a distributed algorithm to realize volumetric harmonic mapping (VHM of the UTC mesh under spherical boundary condition. It is a one-to-one map that yields virtual coordinates for each node in the network without or with one internal hole. Since a boundary has been mapped to a sphere, node-based greedy routing is always successful thereon. At the same time, we exploit the UTC mesh to develop a face-based greedy routing algorithm and prove its success at internal nodes. To deliver a data packet to its destination, face-based and node-based greedy routing algorithms are employed alternately at internal and boundary UTCs, respectively. For networks with multiple internal holes, a segmentation and tunnel-based routing strategy is proposed on top of VHM to support global end-to-end routing. As far as we know, this is the first work that realizes truly deterministic routing with constant-bounded storage and computation in general 3D wireless sensor networks.

Route Fidelity during Marine Megafauna Migration

Directory of Open Access Journals (Sweden)

Travis W. Horton

2017-12-01

Full Text Available The conservation and protection of marine megafauna require robust knowledge of where and when animals are located. Yet, our ability to predict animal distributions in space and time remains limited due to difficulties associated with studying elusive animals with large home ranges. The widespread deployment of satellite telemetry technology creates unprecedented opportunities to remotely monitor animal movements and to analyse the spatial and temporal trajectories of these movements from a variety of geophysical perspectives. Reproducible patterns in movement trajectories can help elucidate the potential mechanisms by which marine megafauna navigate across vast expanses of open-ocean. Here, we present an empirical analysis of humpback whale (Megaptera novaeangliae, great white shark (Carcharodon carcharias, and northern elephant seal (Mirounga angustirostris satellite telemetry-derived route fidelity movements in magnetic and gravitational coordinates. Our analyses demonstrate that: (1 humpback whales, great white sharks and northern elephant seals are capable of performing route fidelity movements across millions of square kilometers of open ocean with a spatial accuracy of better than 150 km despite temporal separations as long as 7 years between individual movements; (2 route fidelity movements include significant (p < 0.05 periodicities that are comparable in duration to the lunar cycles and semi-cycles; (3 latitude and bedrock-dependent gravitational cues are stronger predictors of route fidelity movements than spherical magnetic coordinate cues when analyzed with respect to the temporally dependent moon illumination cycle. We further show that both route fidelity and non-route fidelity movement trajectories, for all three species, describe overlapping in-phase or antiphase sinusoids when individual movements are normalized to the gravitational acceleration present at migratory departure sites. Although these empirical results provide an

Risk assessment of alternative proliferation routes

International Nuclear Information System (INIS)

Ahmed, S.; Husseiny, A.A.

1982-01-01

Multi-Attribute Decision Theory is applied to rank II alternative routes to nuclear proliferation in order of difficulty in acquiring nuclear weapons by nonnuclear countries. The method is based on reducing the various variables affecting the decision to a single function providing a measure for the proliferation route. The results indicate that the most difficult route to obtain atomic weapons is through nuclear power reactors, specifically the liquid-metal fast breeder reactor, heavy water Canada deuterium uranium reactor, and light water reactors such as boiling water and pressurized water reactors. The easiest routes are supercritical centrifuge isotope separation, laser isotope separation, and research reactor. However, nonnuclear routes available that result in substantial damage to life and property are easier than any nuclear route

Online constrained model-based reinforcement learning

CSIR Research Space (South Africa)

Van Niekerk, B

2017-08-01

Full Text Available Constrained Model-based Reinforcement Learning Benjamin van Niekerk School of Computer Science University of the Witwatersrand South Africa Andreas Damianou∗ Amazon.com Cambridge, UK Benjamin Rosman Council for Scientific and Industrial Research, and School... MULTIPLE SHOOTING Using direct multiple shooting (Bock and Plitt, 1984), problem (1) can be transformed into a structured non- linear program (NLP). First, the time horizon [t0, t0 + T ] is partitioned into N equal subintervals [tk, tk+1] for k = 0...

Perspectives on Constraining a Cosmological Constant-Type Parameter with Pulsar Timing in the Galactic Center

Directory of Open Access Journals (Sweden)

Lorenzo Iorio

2018-03-01

Full Text Available Independent tests aiming to constrain the value of the cosmological constant Λ are usually difficult because of its extreme smallness ( Λ ≃ 1 × 10 - 52 m - 2 , or 2 . 89 × 10 - 122 in Planck units . Bounds on it from Solar System orbital motions determined with spacecraft tracking are currently at the ≃ 10 - 43 – 10 - 44 m - 2 ( 5 – 1 × 10 - 113 in Planck units level, but they may turn out to be optimistic since Λ has not yet been explicitly modeled in the planetary data reductions. Accurate ( σ τ p ≃ 1 – 10 μ s timing of expected pulsars orbiting the Black Hole at the Galactic Center, preferably along highly eccentric and wide orbits, might, at least in principle, improve the planetary constraints by several orders of magnitude. By looking at the average time shift per orbit Δ δ τ ¯ p Λ , an S2-like orbital configuration with e = 0 . 8839 , P b = 16 yr would permit a preliminarily upper bound of the order of Λ ≲ 9 × 10 - 47 m - 2 ≲ 2 × 10 - 116 in Planck units if only σ τ p were to be considered. Our results can be easily extended to modified models of gravity using Λ -type parameters.

Anomalous ortho-para conversion of solid hydrogen in constrained geometries

International Nuclear Information System (INIS)

Rall, M.; Brison, J.P.; Sullivan, N.S.

1991-01-01

Using cw NMR techniques, we have measured the ortho-para conversion of solid hydrogen constrained to the interior of the molecular cages of zeolite. The conversion observed in the constrained geometry is very different from that of bulk solid hydrogen. Two distinct conversion rates were observed for short and long times. An apparently bimolecular conversion rate of 0.43% h -1 (one-fourth of the bulk value) dominates during the first 500 h, and the rate then increases to 2.2% h -1 . The initial slow rate is explained in terms of a reduced number of nearest neighbors and possible wall effects, and the fast rate is attributed to the formation of small ortho-H 2 Rclusters at later times. Surface effects due to magnetic impurities do not appear to determine the conversion rate in the samples studied

Nested Sampling with Constrained Hamiltonian Monte Carlo

OpenAIRE

Betancourt, M. J.

2010-01-01

Nested sampling is a powerful approach to Bayesian inference ultimately limited by the computationally demanding task of sampling from a heavily constrained probability distribution. An effective algorithm in its own right, Hamiltonian Monte Carlo is readily adapted to efficiently sample from any smooth, constrained distribution. Utilizing this constrained Hamiltonian Monte Carlo, I introduce a general implementation of the nested sampling algorithm.

Transportation Routing Analysis Geographic Information System -- TRAGIS, progress on improving a routing tool

International Nuclear Information System (INIS)

Johnson, P.E.; Lester, P.B.

1998-05-01

The Transportation Routing Analysis Geographic Information System (TRAGIS) model provides a useful tool to calculate and analyze transportation routes for radioactive materials within the continental US. This paper outlines some of the features available in this model

Collective network routing

Science.gov (United States)

Hoenicke, Dirk

2014-12-02

Disclosed are a unified method and apparatus to classify, route, and process injected data packets into a network so as to belong to a plurality of logical networks, each implementing a specific flow of data on top of a common physical network. The method allows to locally identify collectives of packets for local processing, such as the computation of the sum, difference, maximum, minimum, or other logical operations among the identified packet collective. Packets are injected together with a class-attribute and an opcode attribute. Network routers, employing the described method, use the packet attributes to look-up the class-specific route information from a local route table, which contains the local incoming and outgoing directions as part of the specifically implemented global data flow of the particular virtual network.

Route Scherrer and Route Einstein closed for construction work

CERN Multimedia

2015-01-01

Please note that Route Scherrer will be inaccessible for two and a half months from the beginning of March and that part of Route Einstein will be closed for two weeks from the end of February.   Figure 1. The part of Route Scherrer between Building 510 and Building 53 (see Figure 1) will be closed from the beginning of March until mid-May for civil engineering works.   The superheated water pipes supplying the buildings in this area date back to 1959 and therefore present a significant risk of leakage. In order to ensure the reliable supply of superheated water, and, by extension, heating, to all premises near the Main Building (i.e. Buildings 500, 501, 503, 60, 62, 63 and 64), a new buried service duct will be installed between the basements of Buildings 53 and 61 to house a new superheated water pipe. Figure 2. The following car parks will, however, remain accessible for the duration of the works: the Cèdres car park, the car park for Buildings 4 and 5, and the ca...

Highway route controlled quantity shipment routing reports - An overview

International Nuclear Information System (INIS)

Cashwell, J.W.; Welles, B.W.; Welch, M.J.

1989-01-01

US Department of Transportation (DOT) regulations require a postnotification report from the shipper for all shipments of radioactive materials categorized as a Highway Route Controlled Quantity. These postnotification reports, filed in compliance with 49 CFR 172.203(d), have been compiled by the DOT in a database known as the Radioactive Materials Routing Report (RAMRT) since 1982. The data were sorted by each of its elements to establish historical records and trends of Highway Route Controlled Quantity shipments from 1982 through 1987. Approximately 1520 records in the RAMRT database were compiled for this analysis. Approximately half of the shipments reported for the study period were from the US Department of Energy (DOE) and its contractors, with the others being commercial movements. Two DOE installations, EG and G Idaho and Oak Ridge, accounted for nearly half of the DOE activities. Similarly, almost half of the commercial movements were reported by two vendors, Nuclear Assurance Corporation and Transnuclear, Incorporated. Spent fuel from power and research reactors accounted for approximately half of all shipments

Comparison of transhepatic and extrahepatic routes for EUS-guided rendezvous procedure for distal CBD obstruction.

Science.gov (United States)

Dhir, Vinay; Bhandari, Suryaprakash; Bapat, Mukta; Joshi, Nitin; Vivekanandarajah, Suhirdan; Maydeo, Amit

2013-04-01

EUS-guided rendezvous procedure (EUS-RV) can be done by the transhepatic (TH) or the extrahepatic (EH) route. There is no data on the preferred access route when both routes are available. To compare the success, complications, and duration of hospitalization for patients undergoing EUS-RV by the TH or the EH route. Patients with distal common bile duct (CBD) obstruction, who failed selective cannulation, underwent EUS-RV by the TH route through the stomach or the EH route through the duodenum. A total of 35 patients were analysed (17 TH, 18 EH). The mean procedure time was significantly longer for the TH group (34.4 vs. 25.7 min; p = 0.0004). There was no difference in the technical success (94.1 vs. 100%). However, the TH group had a higher incidence of post-procedure pain (44.1 vs. 5.5%; p = 0.017), bile leak (11.7 vs. 0; p = 0.228), and air under diaphragm (11.7 vs. 0; p = 0.228). All bile leaks were small and managed conservatively. Duration of hospitalization was significantly higher for the TH group (2.52 vs. 0.17 days; p = 0.015). EUS-RV has similar success rate by the TH or the EH route. However, the TH route has higher post-procedure pain, longer procedure time, and longer duration of hospitalization. The EH route should be preferred for EUS-RV in patients with distal CBD obstruction when both access routes are technically feasible.

US Hazardous Materials Routes, Geographic WGS84, BTS (2006) [hazardous_material_routes_BTS_2006

Data.gov (United States)

Louisiana Geographic Information Center — The Federal Motor Carrier Safety Administration (FMCSA) Hazardous Material Routes were developed using the 2004 First Edition TIGER/Line files. The routes are...

Constrained control of a once-through boiler with recirculation

DEFF Research Database (Denmark)

Trangbæk, K

2008-01-01

There is an increasing need to operate power plants at low load for longer periods of time. When a once-through boiler operates at a sufficiently low load, recirculation is introduced, significantly altering the control structure. This paper illustrates the possibilities for using constrained con...

A MODIFIED ROUTE DISCOVERY APPROACH FOR DYNAMIC SOURCE ROUTING (DSR PROTOCOL IN MOBILE AD-HOC NETWORKS

Directory of Open Access Journals (Sweden)

Alaa Azmi Allahham

2017-02-01

Full Text Available Mobile Ad-hoc networks (MANETs involved in many applications, whether commercial or military because of their characteristics that do not depend on the infrastructure as well as the freedom movement of their elements, but in return has caused this random mobility of the nodes many of the challenges, where the routing is considered one of these challenges. There are many types of routing protocols that operate within MANET networks, which responsible for finding paths between the source and destination nodes with the modernization of these paths which are constantly changing due to the dynamic topology of the network stemming from the constant random movement of the nodes. The DSR (Dynamic Source Routing routing protocol algorithm is one of these routing protocols which consist of two main stages; route discovery and maintenance, where the route discovery algorithm operates based on blind flooding of request messages. blind flooding is considered as the most well known broadcasting mechanism, it is inefficient in terms of communication and resource utilization, which causing increasing the probability of collisions, repeating send several copies of the same message, as well as increasing the delay. Hence, a new mechanism in route discovery stage and in caching the routes in DSR algorithm according to the node's location in the network and the direction of the broadcast is proposed for better performance especially in terms of delay as well as redundant packets rate. The implementation of proposed algorithms showed positive results in terms of delay, overhead, and improve the performance of MANETs in general.

A Hybrid Method for the Modelling and Optimisation of Constrained Search Problems

Directory of Open Access Journals (Sweden)

Sitek Pawel

2014-08-01

Full Text Available The paper presents a concept and the outline of the implementation of a hybrid approach to modelling and solving constrained problems. Two environments of mathematical programming (in particular, integer programming and declarative programming (in particular, constraint logic programming were integrated. The strengths of integer programming and constraint logic programming, in which constraints are treated in a different way and different methods are implemented, were combined to use the strengths of both. The hybrid method is not worse than either of its components used independently. The proposed approach is particularly important for the decision models with an objective function and many discrete decision variables added up in multiple constraints. To validate the proposed approach, two illustrative examples are presented and solved. The first example is the authors’ original model of cost optimisation in the supply chain with multimodal transportation. The second one is the two-echelon variant of the well-known capacitated vehicle routing problem.

Route-specific analysis for radioactive materials transportation

International Nuclear Information System (INIS)

1986-01-01

This report addresses a methodology for route-specific analysis, of which route-selection is one aspect. Identification and mitigation of specific hazards along a chosen route is another important facet of route-specific analysis. Route-selection and route-specific mitigation are two tools to be used in minimizing the risk of radioactive materials transportation and promoting public confidence. Other tools exist to improve the safety of transportation under the Nuclear Waste Policy Act. Selection of a transportation mode and other, non-route-specific measures, such as improved driver training and improved cask designs, are additional tools to minimize transportation risk and promote public confidence. This report addresses the route-specific analysis tool and does not attempt to evaluate its relative usefulness as compared to other available tools. This report represents a preliminary attempt to develop a route-specific analysis methodlogy. The Western Interstate Energy Board High-Level Waste Committee has formed a Route-Specific Analysis Task Force which will build upon the methodology proposed in this Staff Report. As western states continue to investigate route-specific analysis issues, it is expected that the methodology will evolve into a more refined product representing the views of a larger group of interested parties in the West

Path-Constrained Motion Planning for Robotics Based on Kinematic Constraints

NARCIS (Netherlands)

Dijk, van N.J.M.; Wouw, van de N.; Pancras, W.C.M.; Nijmeijer, H.

2007-01-01

Common robotic tracking tasks consist of motions along predefined paths. The design of time-optimal path-constrained trajectories for robotic applications is discussed in this paper. To increase industrial applicability, the proposed method accounts for robot kinematics together with actuator

Bellman Ford algorithm - in Routing Information Protocol (RIP)

Science.gov (United States)

Krianto Sulaiman, Oris; Mahmud Siregar, Amir; Nasution, Khairuddin; Haramaini, Tasliyah

2018-04-01

In a large scale network need a routing that can handle a lot number of users, one of the solutions to cope with large scale network is by using a routing protocol, There are 2 types of routing protocol that is static and dynamic, Static routing is manually route input based on network admin, while dynamic routing is automatically route input formed based on existing network. Dynamic routing is efficient used to network extensively because of the input of route automatic formed, Routing Information Protocol (RIP) is one of dynamic routing that uses the bellman-ford algorithm where this algorithm will search for the best path that traversed the network by leveraging the value of each link, so with the bellman-ford algorithm owned by RIP can optimize existing networks.

The bounds of feasible space on constrained nonconvex quadratic programming

Science.gov (United States)

Zhu, Jinghao

2008-03-01

This paper presents a method to estimate the bounds of the radius of the feasible space for a class of constrained nonconvex quadratic programmingsE Results show that one may compute a bound of the radius of the feasible space by a linear programming which is known to be a P-problem [N. Karmarkar, A new polynomial-time algorithm for linear programming, Combinatorica 4 (1984) 373-395]. It is proposed that one applies this method for using the canonical dual transformation [D.Y. Gao, Canonical duality theory and solutions to constrained nonconvex quadratic programming, J. Global Optimization 29 (2004) 377-399] for solving a standard quadratic programming problem.

Mean Velocity Prediction Information Feedback Strategy in Two-Route Systems under ATIS

Directory of Open Access Journals (Sweden)

Jianqiang Wang

2015-02-01

Full Text Available Feedback contents of previous information feedback strategies in advanced traveler information systems are almost real-time traffic information. Compared with real-time information, prediction traffic information obtained by a reliable and effective prediction algorithm has many undisputable advantages. In prediction information environment, a traveler is prone to making a more rational route-choice. For these considerations, a mean velocity prediction information feedback strategy (MVPFS is presented. The approach adopts the autoregressive-integrated moving average model (ARIMA to forecast short-term traffic flow. Furthermore, prediction results of mean velocity are taken as feedback contents and displayed on a variable message sign to guide travelers' route-choice. Meanwhile, discrete choice model (Logit model is selected to imitate more appropriately travelers' route-choice behavior. In order to investigate the performance of MVPFS, a cellular automaton model with ARIMA is adopted to simulate a two-route scenario. The simulation shows that such innovative prediction feedback strategy is feasible and efficient. Even more importantly, this study demonstrates the excellence of prediction feedback ideology.

Long-Range Correlations and Memory in the Dynamics of Internet Interdomain Routing.

Directory of Open Access Journals (Sweden)

Maksim Kitsak

Full Text Available Data transfer is one of the main functions of the Internet. The Internet consists of a large number of interconnected subnetworks or domains, known as Autonomous Systems (ASes. Due to privacy and other reasons the information about what route to use to reach devices within other ASes is not readily available to any given AS. The Border Gateway Protocol (BGP is responsible for discovering and distributing this reachability information to all ASes. Since the topology of the Internet is highly dynamic, all ASes constantly exchange and update this reachability information in small chunks, known as routing control packets or BGP updates. In the view of the quick growth of the Internet there are significant concerns with the scalability of the BGP updates and the efficiency of the BGP routing in general. Motivated by these issues we conduct a systematic time series analysis of BGP update rates. We find that BGP update time series are extremely volatile, exhibit long-term correlations and memory effects, similar to seismic time series, or temperature and stock market price fluctuations. The presented statistical characterization of BGP update dynamics could serve as a basis for validation of existing and developing better models of Internet interdomain routing.

Surface-Wave Pulse Routing around Sharp Right Angles

Science.gov (United States)

Gao, Z.; Xu, H.; Gao, F.; Zhang, Y.; Luo, Y.; Zhang, B.

2018-04-01

Surface-plasmon polaritons (SPPs), or localized electromagnetic surface waves propagating on a metal-dielectric interface, are deemed promising information carriers for future subwavelength terahertz and optical photonic circuitry. However, surface waves fundamentally suffer from scattering loss when encountering sharp corners in routing and interconnection of photonic signals. Previous approaches enabling scattering-free surface-wave guidance around sharp corners are limited to either volumetric waveguide environments or extremely narrow bandwidth, being unable to guide a surface-wave pulse (SPP wave packet) on an on-chip platform. Here, in a surface-wave band-gap crystal implemented on a single metal surface, we demonstrate in time-domain routing a surface-wave pulse around multiple sharp right angles without perceptible scattering. Our work not only offers a solution to on-chip surface-wave pulse routing along an arbitrary path, but it also provides spatiotemporal information on the interplay between surface-wave pulses and sharp corners, both of which are desirable in developing high-performance large-scale integrated photonic circuits.

Dynamic origin-to-destination routing of wirelessly connected, autonomous vehicles on a congested network

Science.gov (United States)

Davis, L. C.

2017-07-01

Up-to-date information wirelessly communicated among vehicles can be used to select the optimal route between a given origin and destination. To elucidate how to make use of such information, simulations are performed for autonomous vehicles traveling on a square lattice of roads. All the possible routes between the origin and the destination (without backtracking) are of the same length. Congestion is the only determinant of delay. At each intersection, right-of-way is given to the closest vehicle. There are no traffic lights. Trip times of a subject vehicle are recorded for various initial conditions using different routing algorithms. Surprisingly, the simplest algorithm, which is based on the total number of vehicles on a route, is as good as one based on computing travel times from the average velocity of vehicles on each road segment.

Capturing Hotspots For Constrained Indoor Movement

DEFF Research Database (Denmark)

Ahmed, Tanvir; Pedersen, Torben Bach; Lu, Hua

2013-01-01

Finding the hotspots in large indoor spaces is very important for getting overloaded locations, security, crowd management, indoor navigation and guidance. The tracking data coming from indoor tracking are huge in volume and not readily available for finding hotspots. This paper presents a graph......-based model for constrained indoor movement that can map the tracking records into mapping records which represent the entry and exit times of an object in a particular location. Then it discusses the hotspots extraction technique from the mapping records....

Predicting transportation routes for radioactive wastes

International Nuclear Information System (INIS)

Joy, D.S.; Johnson, P.E.; Clarke, D.B.; McGuire, S.C.

1981-01-01

Oak Ridge National Laboratory (ORNL) has been involved in transportation logistics of radioactive wastes as part of the overall waste transportation program. A Spent Fuel Logistics Model (SFLM), was developed to predict overall material balances representing the flow of spent fuel assemblies from reactors to away-from-reactor storage facilities and/or to federal repositories. The transportation requirements to make these shipments are also itemized. The next logical step in the overall transportation project was the development of a set of computer codes which would predict likely transportation routes for waste shipments. Two separate routing models are now operational at ORNL. Routes for truck transport can be estimated with the HIGHWAY program, and rail and barge routes can be predicted with the INTERLINE model. This paper discusses examples of the route estimates and applications of the routing models

Conditions for the Solvability of the Linear Programming Formulation for Constrained Discounted Markov Decision Processes

Energy Technology Data Exchange (ETDEWEB)

Dufour, F., E-mail: dufour@math.u-bordeaux1.fr [Institut de Mathématiques de Bordeaux, INRIA Bordeaux Sud Ouest, Team: CQFD, and IMB (France); Prieto-Rumeau, T., E-mail: tprieto@ccia.uned.es [UNED, Department of Statistics and Operations Research (Spain)

2016-08-15

We consider a discrete-time constrained discounted Markov decision process (MDP) with Borel state and action spaces, compact action sets, and lower semi-continuous cost functions. We introduce a set of hypotheses related to a positive weight function which allow us to consider cost functions that might not be bounded below by a constant, and which imply the solvability of the linear programming formulation of the constrained MDP. In particular, we establish the existence of a constrained optimal stationary policy. Our results are illustrated with an application to a fishery management problem.

Efficiency of Choice Set Generation Methods for Bicycle Routes

DEFF Research Database (Denmark)

Halldórsdóttir, Katrín; Rieser-Schüssler, Nadine; W. Axhausen, Kay

behaviour, observed choices and alternatives composing the choice set of each cyclist are necessary. However, generating the alternative choice sets can prove challenging. This paper analyses the efficiency of various choice set generation methods for bicycle routes in order to contribute to our...... travelling information with GPS loggers, compared to self-reported RP data, is more accurate geographic locations and routes. Also, the GPS traces give more reliable information on times and prevent trip underreporting, and it is possible to collect information on many trips by the same person without...

Partial Path Column Generation for the Vehicle Routing Problem

DEFF Research Database (Denmark)

Jepsen, Mads Kehlet; Petersen, Bjørn

This paper presents a column generation algorithm for the Capacitated Vehicle Routing Problem (CVRP) and the Vehicle Routing Problem with Time Windows (VRPTW). Traditionally, column generation models of the CVRP and VRPTW have consisted of a Set Partitioning master problem with each column...... of the giant tour’; a so-called partial path, i.e., not necessarily starting and ending in the depot. This way, the length of the partial path can be bounded and a better control of the size of the solution space for the pricing problem can be obtained....

RSRP: A Robust Secure Routing Protocol in MANET

Directory of Open Access Journals (Sweden)

Sinha Ditipriya

2014-05-01

Full Text Available In this paper, we propose a novel algorithm RSRP to build a robust secure routing protocol in mobile ad-hoc networks (MANETs. This algorithm is based on some basic schemes such as RSA_CRT for encryption and decryption of messages; CRT for safety key generation, Shamir’s secret sharing principle for generation of secure routes. Those routes which are free from any malicious node and which belong to the set of disjoint routes between a source-destination pair are considered as probable routes. Shamir’s secret sharing principle is applied on those probable routes to obtain secure routes. Finally, most trustworthy and stable route is selected among those secure routes. Selection of the final route depends on some criteria of the nodes present in a route e.g.: battery power, mobility and trust value. In addition, complexity of key generation is reduced to a large extent by using RSA-CRT instead of RSA. In turn, the routing becomes less expensive and most secure and robust one. Performance of this routing protocol is then compared with non-secure routing protocols (AODV and DSR, secure routing scheme using secret sharing, security routing protocol using ZRP and SEAD depending on basic characteristics of these protocols. All such comparisons show that RSRP shows better performance in terms of computational cost, end-to-end delay and packet dropping in presence of malicious nodes in the MANET, keeping the overhead in terms of control packets same as other secure routing protocols.

OPTIMASI OLSR ROUTING PROTOCOL PADA JARINGAN WIRELESS MESH DENGAN ADAPTIVE REFRESHING TIME INTERVAL DAN ENHANCE MULTI POINT RELAY SELECTING ALGORITHM

Directory of Open Access Journals (Sweden)

Faosan Mapa

2014-01-01

Full Text Available Normal 0 false false false IN X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Wireless Mesh Network (WMN adalah suatu konektivitas jaringan yang self-organized, self-configured dan multi-hop. Tujuan dari WMN adalah menawarkan pengguna suatu bentuk jaringan nirkabel yang dapat dengan mudah berkomunikasi dengan jaringan konvensional dengan kecepatan tinggi dan dengan cakupan yang lebih luas serta biaya awal yang minimal. Diperlukan suatu desain protokol routing yang efisien untuk WMN yang secara adaptif dapat mendukung mesh routers dan mesh clients. Dalam tulisan ini, diusulkan untuk mengoptimalkan protokol OLSR, yang merupakan protokol routing proaktif. Digunakan heuristik yang meningkatkan protokol OLSR melalui adaptive refreshing time interval dan memperbaiki metode MPR selecting algorithm. Suatu analisa dalam meningkatkan protokol OLSR melalui adaptive refreshing time interval dan memperbaiki algoritma pemilihan MPR menunjukkan kinerja yang signifikan dalam hal throughput jika dibandingkan dengan protokol OLSR yang asli. Akan tetapi, terdapat kenaikan dalam hal delay. Pada simulasi yang dilakukan dapat disimpulkan bahwa OLSR dapat dioptimalkan dengan memodifikasi pemilihan node MPR berdasarkan cost effective dan penyesuaian waktu interval refreshing hello message sesuai dengan keadaan

Human risk assessment of dermal and inhalation exposures to chemicals assessed by route-to-route extrapolation: the necessity of kinetic data.

Science.gov (United States)

Geraets, Liesbeth; Bessems, Jos G M; Zeilmaker, Marco J; Bos, Peter M J

2014-10-01

In toxicity testing the oral route is in general the first choice. Often, appropriate inhalation and dermal toxicity data are absent. Risk assessment for these latter routes usually has to rely on route-to-route extrapolation starting from oral toxicity data. Although it is generally recognized that the uncertainties involved are (too) large, route-to-route extrapolation is applied in many cases because of a strong need of an assessment of risks linked to a given exposure scenario. For an adequate route-to-route extrapolation the availability of at least some basic toxicokinetic data is a pre-requisite. These toxicokinetic data include all phases of kinetics, from absorption (both absorbed fraction and absorption rate for both the starting route and route of interest) via distribution and biotransformation to excretion. However, in practice only differences in absorption between the different routes are accounted for. The present paper demonstrates the necessity of route-specific absorption data by showing the impact of its absence on the uncertainty of the human health risk assessment using route-to-route extrapolation. Quantification of the absorption (by in vivo, in vitro or in silico methods), particularly for the starting route, is considered essential. Copyright © 2014 Elsevier Inc. All rights reserved.

An optimization algorithm for a capacitated vehicle routing problem ...

Indian Academy of Sciences (India)

In this paper, vehicle routing problem (VRP) with time windows and real world constraints are considered as a real-world application on google maps. Also, tabu search is used and Hopfield neural networks is utilized. Basic constraints consist of customer demands, time windows, vehicle speed, vehicle capacity andworking ...

Airspace Technology Demonstration 3 (ATD-3): Dynamic Weather Routes (DWR) Technology Transfer Document Summary Version 1.0

Science.gov (United States)

Sheth, Kapil; Wang, Easter Mayan Chan

2016-01-01

Airspace Technology Demonstration #3 (ATD-3) is part of NASA's Airspace Operations and Safety Program (AOSP) - specifically, its Airspace Technology Demonstrations (ATD) Project. ATD-3 is a multiyear research and development effort which proposes to develop and demonstrate automation technologies and operating concepts that enable air navigation service providers and airspace users to continuously assess weather, winds, traffic, and other information to identify, evaluate, and implement workable opportunities for flight plan route corrections that can result in significant flight time and fuel savings in en route airspace. In order to ensure that the products of this tech-transfer are relevant and useful, NASA has created strong partnerships with the FAA and key industry stakeholders. This summary document and accompanying technology artifacts satisfy the first of three Research Transition Products (RTPs) defined in the Applied Traffic Flow Management (ATFM) Research Transition Team (RTT) Plan. This transfer consists of NASA's legacy Dynamic Weather Routes (DWR) work for efficient routing for en-route weather avoidance. DWR is a ground-based trajectory automation system that continuously and automatically analyzes active airborne aircraft in en route airspace to identify opportunities for simple corrections to flight plan routes that can save significant flying time, at least five minutes wind-corrected, while avoiding weather and considering traffic conflicts, airspace sector congestion, special use airspace, and FAA routing restrictions. The key benefit of the DWR concept is to let automation continuously and automatically analyze active flights to find those where simple route corrections can save significant time and fuel. Operators are busy during weather events. It is more effective to let automation find the opportunities for high-value route corrections.

Effective Privacy-Preserving Online Route Planning

DEFF Research Database (Denmark)

Vicente, Carmen Ruiz; Assent, Ira; Jensen, Christian S.

2011-01-01

An online Route Planning Service (RPS) computes a route from one location to another. Current RPSs such as Google Maps require the use of precise locations. However, some users may not want to disclose their source and destination locations due to privacy concerns. An approach that supplies fake...... privacy. The solution re-uses a standard online RPS rather than replicate this functionality, and it needs no trusted third party. The solution is able to compute the exact results without leaking of the exact locations to the RPS or un-trusted parties. In addition, we provide heuristics that reduce...... the number of times that the RPS needs to be queried, and we also describe how the accuracy and privacy requirements can be relaxed to achieve better performance. An empirical study offers insight into key properties of the approach....

Vehicle Routing With User Generated Trajectory Data

DEFF Research Database (Denmark)

Ceikute, Vaida; Jensen, Christian S.

Rapidly increasing volumes of GPS data collected from vehicles provide new and increasingly comprehensive insight into the routes that drivers prefer. While routing services generally compute shortest or fastest routes, recent studies suggest that local drivers often prefer routes that are neithe...

Using Seasonal Forecasting Data for Vessel Routing

Science.gov (United States)

Bell, Ray; Kirtman, Ben

2017-04-01

We present an assessment of seasonal forecasting of surface wind speed, significant wave height and ocean surface current speed in the North Pacific for potential use of vessel routing from Singapore to San Diego. WaveWatchIII is forced with surface winds and ocean surface currents from the Community Climate System Model 4 (CCSM4) retrospective forecasts for the period of 1982-2015. Several lead time forecasts are used from zero months to six months resulting in 2,720 model years, ensuring the findings from this study are robust. July surface wind speed and significant wave height can be skillfully forecast with a one month lead time, with the western North Pacific being the most predictable region. Beyond May initial conditions (lead time of two months) the El Niño Southern Oscillation (ENSO) Spring predictability barrier limits skill of significant wave height but there is skill for surface wind speed with January initial conditions (lead time of six months). In a separate study of vessel routing between Norfolk, Virginia and Gibraltar we demonstrate the benefit of a multimodel approach using the North American Multimodel Ensemble (NMME). In collaboration with Charles River Analytics an all-encompassing forecast is presented by using machine learning on the various ensembles which can be using used for industry applications.

Getting to the elephants: Gesture and preschoolers' comprehension of route direction information.

Science.gov (United States)

Austin, Elizabeth E; Sweller, Naomi

2017-11-01

During early childhood, children find spatial tasks such as following novel route directions challenging. Spatial tasks place demands on multiple cognitive processes, including language comprehension and memory, at a time in development when resources are limited. As such, gestures accompanying route directions may aid comprehension and facilitate task performance by scaffolding cognitive processes, including language and memory processing. This study examined the effect of presenting gesture during encoding on spatial task performance during early childhood. Three- to five-year-olds were presented with verbal route directions through a zoo-themed spatial array and, depending on assigned condition (no gesture, beat gesture, or iconic/deictic gesture), accompanying gestures. Children presented with verbal route directions accompanied by a combination of iconic (pantomime) and deictic (pointing) gestures verbally recalled more than children presented with beat gestures (rhythmic hand movements) or no gestures accompanying the route directions. The presence of gesture accompanying route directions similarly influenced physical route navigation, such that children presented with gesture (beat, pantomime, and pointing) navigated the route more accurately than children presented with no gestures. Across all gesture conditions, location information (e.g., the penguin pond) was recalled more than movement information (e.g., go around) and descriptive information (e.g., bright red). These findings suggest that speakers' gestures accompanying spatial task information influence listeners' recall and task performance. Copyright © 2017 Elsevier Inc. All rights reserved.

Routing-based synthesis of digital microfluidic biochips

DEFF Research Database (Denmark)

Maftei, Elena; Pop, Paul; Madsen, Jan

2012-01-01

Microfluidic biochips are replacing the conventional biochemical analyzers, and are able to integrate on-chip all the necessary functions for biochemical analysis. The “digital” biochips are manipulating liquids as discrete droplets on a two-dimensional array of electrodes. Basic microfluidic...... electrodes are considered occupied during the operation execution, although the droplet uses only one electrode at a time. Moreover, the operations can actually be performed by routing the droplets on any sequence of electrodes on the microfluidic array. Hence, in this paper, we eliminate the concept...... on the surface of the microfluidic array. We have extended the GRASP-based algorithm to consider contamination avoidance during routing-based synthesis. Several real-life examples and synthetic benchmarks are used to evaluate the proposed approaches....

Zone routing in a torus network

Science.gov (United States)

Chen, Dong; Heidelberger, Philip; Kumar, Sameer

2013-01-29

A system for routing data in a network comprising a network logic device at a sending node for determining a path between the sending node and a receiving node, wherein the network logic device sets one or more selection bits and one or more hint bits within the data packet, a control register for storing one or more masks, wherein the network logic device uses the one or more selection bits to select a mask from the control register and the network logic device applies the selected mask to the hint bits to restrict routing of the data packet to one or more routing directions for the data packet within the network and selects one of the restricted routing directions from the one or more routing directions and sends the data packet along a link in the selected routing direction toward the receiving node.

Entanglement-Gradient Routing for Quantum Networks.

Science.gov (United States)

Gyongyosi, Laszlo; Imre, Sandor

2017-10-27

We define the entanglement-gradient routing scheme for quantum repeater networks. The routing framework fuses the fundamentals of swarm intelligence and quantum Shannon theory. Swarm intelligence provides nature-inspired solutions for problem solving. Motivated by models of social insect behavior, the routing is performed using parallel threads to determine the shortest path via the entanglement gradient coefficient, which describes the feasibility of the entangled links and paths of the network. The routing metrics are derived from the characteristics of entanglement transmission and relevant measures of entanglement distribution in quantum networks. The method allows a moderate complexity decentralized routing in quantum repeater networks. The results can be applied in experimental quantum networking, future quantum Internet, and long-distance quantum communications.

The Pyramidal Capacitated Vehicle Routing Problem

DEFF Research Database (Denmark)

Lysgaard, Jens

This paper introduces the Pyramidal Capacitated Vehicle Routing Problem (PCVRP) as a restricted version of the Capacitated Vehicle Routing Problem (CVRP). In the PCVRP each route is required to be pyramidal in a sense generalized from the Pyramidal Traveling Salesman Problem (PTSP). A pyramidal...

The pyramidal capacitated vehicle routing problem

DEFF Research Database (Denmark)

Lysgaard, Jens

2010-01-01

This paper introduces the pyramidal capacitated vehicle routing problem (PCVRP) as a restricted version of the capacitated vehicle routing problem (CVRP). In the PCVRP each route is required to be pyramidal in a sense generalized from the pyramidal traveling salesman problem (PTSP). A pyramidal...

QoS Supported IPTV Service Architecture over Hybrid-Tree-Based Explicit Routed Multicast Network

Directory of Open Access Journals (Sweden)

Chih-Chao Wen

2012-01-01

Full Text Available With the rapid advance in multimedia streaming and multicast transport technology, current IP multicast protocols, especially PIM-SM, become the major channel delivery mechanism for IPTV system over Internet. The goals for IPTV service are to provide two-way interactive services for viewers to select popular program channel with high quality for watching during fast channel surfing period. However, existing IP multicast protocol cannot meet above QoS requirements for IPTV applications between media server and subscribers. Therefore, we propose a cooperative scheme of hybrid-tree based on explicit routed multicast, called as HT-ERM to combine the advantages of shared tree and source tree for QoS-supported IPTV service. To increase network utilization, the constrained shortest path first (CSPF routing algorithm is designed for construction of hybrid tree to deliver the high-quality video stream over watching channel and standard quality over surfing channel. Furthermore, the Resource Reservation Protocol- Traffic Engineering (RSVP-TE is used as signaling mechanism to set up QoS path for multicast channel admission control. Our simulation results demonstrated that the proposed HT-ERM scheme outperforms other multicast QoS-based delivery scheme in terms of channel switching delay, resource utilization, and blocking ratio for IPTV service.

Groundwater availability as constrained by hydrogeology and environmental flows.

Science.gov (United States)

Watson, Katelyn A; Mayer, Alex S; Reeves, Howard W

2014-01-01

Groundwater pumping from aquifers in hydraulic connection with nearby streams has the potential to cause adverse impacts by decreasing flows to levels below those necessary to maintain aquatic ecosystems. The recent passage of the Great Lakes-St. Lawrence River Basin Water Resources Compact has brought attention to this issue in the Great Lakes region. In particular, the legislation requires the Great Lakes states to enact measures for limiting water withdrawals that can cause adverse ecosystem impacts. This study explores how both hydrogeologic and environmental flow limitations may constrain groundwater availability in the Great Lakes Basin. A methodology for calculating maximum allowable pumping rates is presented. Groundwater availability across the basin may be constrained by a combination of hydrogeologic yield and environmental flow limitations varying over both local and regional scales. The results are sensitive to factors such as pumping time, regional and local hydrogeology, streambed conductance, and streamflow depletion limits. Understanding how these restrictions constrain groundwater usage and which hydrogeologic characteristics and spatial variables have the most influence on potential streamflow depletions has important water resources policy and management implications. © 2013, National Ground Water Association.

Time constrained liner shipping network design

DEFF Research Database (Denmark)

Karsten, Christian Vad; Brouer, Berit Dangaard; Desaulniers, Guy

2017-01-01

We present a mathematical model and a solution method for the liner shipping network design problem. The model takes into account coordination between vessels and transit time restrictions on the cargo flow. The solution method is an improvement heuristic, where an integer program is solved...... iteratively to perform moves in a large neighborhood search. Our improvement heuristic is applicable as a real-time decision support tool for a liner shipping company. It can be used to find improvements to the network when evaluating changes in operating conditions or testing different scenarios...

Routed planar networks

Directory of Open Access Journals (Sweden)

David J. Aldous

2016-04-01

Full Text Available Modeling a road network as a planar graph seems very natural. However, in studying continuum limits of such networks it is useful to take {\\em routes} rather than {\\em edges} as primitives. This article is intended to introduce the relevant (discrete setting notion of {\\em routed network} to graph theorists. We give a naive classification of all 71 topologically different such networks on 4 leaves, and pose a variety of challenging research questions.

Space Radiation Measurement on the Polar Route onboard the Korean Commercial Flights

Directory of Open Access Journals (Sweden)

Junga Hwang

2010-03-01

Full Text Available This study was performed by the policy research project of Ministry of Land, Transport and Maritime Affairs, which title is “Developing safety standards and management of space radiation on the polar route”. In this research, total six experiments were performed using Korean commercial flights (B747. Three of those are on the polar route and the other three are on the north pacific route. Space radiation exposure measured on the polar route is the average 84.7 uSv. The simulation result using CARI-6M program gives 84.9 uSv, which is very similar to measured value. For the departure flight using the north pacific route, the measured space radiation is the average 74.4 uSv. It seems that is not so different to use the polar route or not for the return flight because the higher latitude effect causing the increase of space radiation is compensated by the shortened flight time effect causing decreasing space radiation exposure.

Lightweight cryptography for constrained devices

DEFF Research Database (Denmark)

Alippi, Cesare; Bogdanov, Andrey; Regazzoni, Francesco

2014-01-01

Lightweight cryptography is a rapidly evolving research field that responds to the request for security in resource constrained devices. This need arises from crucial pervasive IT applications, such as those based on RFID tags where cost and energy constraints drastically limit the solution...... complexity, with the consequence that traditional cryptography solutions become too costly to be implemented. In this paper, we survey design strategies and techniques suitable for implementing security primitives in constrained devices....

Road Routes for Waste Disposal - MDC_RecyclingRoute

Data.gov (United States)

NSGIC Local Govt | GIS Inventory — This CURBSIDE RECYCLING ROUTES BOUNDARIES LAYER IS A polygon feature class created for the Miami-Dade Department of Solid Waste Management (DSWM). It contains the...

Porcelain tiles by the dry route

International Nuclear Information System (INIS)

Melchiades, F. G.; Daros, M. T.; Boschi, A. O.

2010-01-01

In Brazil, the second largest tile producer of the world, at present, 70% of the tiles are produced by the dry route. One of the main reasons that lead to this development is the fact that the dry route uses approximately 30% less thermal energy them the traditional wet route. The increasing world concern with the environment and the recognition of the central role played by the water also has pointed towards privileging dry processes. In this context the objective of the present work is to study the feasibility of producing high quality porcelain tiles by the dry route. A brief comparison of the dry and wet route, in standard conditions industrially used today to produce tiles that are not porcelain tiles, shows that there are two major differences: the particle sizes obtained by the wet route are usually considerably finer and the capability of mixing the different minerals, the intimacy of the mixture, is also usually better in the wet route. The present work studied the relative importance of these differences and looked for raw materials and operational conditions that would result in better performance and glazed porcelain tiles of good quality. (Author) 7 refs.

Parallel algorithms for placement and routing in VLSI design. Ph.D. Thesis

Science.gov (United States)

Brouwer, Randall Jay

1991-01-01

The computational requirements for high quality synthesis, analysis, and verification of very large scale integration (VLSI) designs have rapidly increased with the fast growing complexity of these designs. Research in the past has focused on the development of heuristic algorithms, special purpose hardware accelerators, or parallel algorithms for the numerous design tasks to decrease the time required for solution. Two new parallel algorithms are proposed for two VLSI synthesis tasks, standard cell placement and global routing. The first algorithm, a parallel algorithm for global routing, uses hierarchical techniques to decompose the routing problem into independent routing subproblems that are solved in parallel. Results are then presented which compare the routing quality to the results of other published global routers and which evaluate the speedups attained. The second algorithm, a parallel algorithm for cell placement and global routing, hierarchically integrates a quadrisection placement algorithm, a bisection placement algorithm, and the previous global routing algorithm. Unique partitioning techniques are used to decompose the various stages of the algorithm into independent tasks which can be evaluated in parallel. Finally, results are presented which evaluate the various algorithm alternatives and compare the algorithm performance to other placement programs. Measurements are presented on the parallel speedups available.

VANET Routing Protocols: Pros and Cons

OpenAIRE

Paul, Bijan; Ibrahim, Md.; Bikas, Md. Abu Naser

2012-01-01

VANET (Vehicular Ad-hoc Network) is a new technology which has taken enormous attention in the recent years. Due to rapid topology changing and frequent disconnection makes it difficult to design an efficient routing protocol for routing data among vehicles, called V2V or vehicle to vehicle communication and vehicle to road side infrastructure, called V2I. The existing routing protocols for VANET are not efficient to meet every traffic scenarios. Thus design of an efficient routing protocol h...

Effect of exposure routes on the relationships of lethal toxicity to rats from oral, intravenous, intraperitoneal and intramuscular routes.

Science.gov (United States)

Ning, Zhong H; Long, Shuang; Zhou, Yuan Y; Peng, Zi Y; Sun, Yi N; Chen, Si W; Su, Li M; Zhao, Yuan H

2015-11-01

The lethal toxicity values (log 1/LD(50)) of 527 aliphatic and aromatic compounds in oral, intravenous, intramuscular and intraperitoneal routes were used to investigate the relationships of log 1/LD(50) from different exposure routes. Regression analysis shows that the log 1/LD(50) values are well correlated between intravenous and intraperitoneal or intramuscular injections. However, the correlations between oral and intravenous or intraperitoneal routes are relatively poor. Comparison of the average residuals indicates that intravenous injection is the most sensitive exposure route and oral administration is the least sensitive exposure route. This is attributed to the difference in kinetic process of toxicity testing. The toxic effect of a chemical can be similar or significantly different between exposure routes, depending on the absorption rates of chemicals into blood. Inclusion of hydrophobic parameter and fractions of ionic forms can improve the correlations between intravenous and intraperitoneal or oral routes, but not between intraperitoneal and oral routes. This is due to the differences of absorption rate in different exposure environments from different routes. Several factors, such as experimental uncertainty, metabolism and toxic kinetics, can affect the correlations between intravenous and intraperitoneal or oral routes. Copyright © 2015 Elsevier Inc. All rights reserved.

Resource-constrained project scheduling: computing lower bounds by solving minimum cut problems

NARCIS (Netherlands)

Möhring, R.H.; Nesetril, J.; Schulz, A.S.; Stork, F.; Uetz, Marc Jochen

1999-01-01

We present a novel approach to compute Lagrangian lower bounds on the objective function value of a wide class of resource-constrained project scheduling problems. The basis is a polynomial-time algorithm to solve the following scheduling problem: Given a set of activities with start-time dependent

Route planning of raw materials transportation in the industrial hub of Mariupol city

Directory of Open Access Journals (Sweden)

Юлія Вікторівна Булгакова

2017-07-01

Full Text Available The multi-modal freight transportation routes planning problem is viewed in this paper. The case study of iron ore deliveries to the metallurgical enterprises of Mariupol from Kryvyi Rih is presented. Based on the analysis of Ukrainian railroads and sea ports infrastructures six possible routes of multi-modal iron ore transportation are built. The paper presents a short review of route planning problem in multi-modal freight transportations, which are use sea and land parts together, regarding decision support methods of routes evaluation and selection. The lack of studies dedicated to fuzzy logic theory application for solving the stated problems is identified. The relevance of fuzzy set application to the route planning problem is proved. Taking into account the peculiarities of iron ore transportations technology, the following criterions of routes evaluation are chosen: «transportation costs», «delivery times», «transportation risks». The model of multicriterion decision-making of routes evaluation and the optimal route selection, based on fuzzy logic theory, is developed. Criteria of routes evaluation are set by three terms Gaussian and sigmoidal membership functions. The approach to each function construction is practice-based and executed together with iron ore supply chain manager. The model is created in MATLAB Fuzzy Logic Tool Box environment using Mamdani’s fuzzy inference

A Time-Slotted On-Demand Routing Protocol for Mobile Ad Hoc Unmanned Vehicle Systems