Operational strategies and matching algorithms are used to ensure the availability and efficient assignment of ride-hailing services.Such operational strategies may result in services that,rather than complement tradi...Operational strategies and matching algorithms are used to ensure the availability and efficient assignment of ride-hailing services.Such operational strategies may result in services that,rather than complement traditional public transport(PT)systems,compete with them in both market(demand)and road-space use(congestion).This paper introduces and evaluates real-time vehicle dispatching strategies that focus on the prioritization of PT use and the complementarity between PT and ride-hailing in multimodal trips.Utilizing a novel two-step ride-matching algorithm,these strategies aim at decreasing travelers'wait times and motivating the use of PT.The agent-based travel demand forecasting model MATSim is used to implement and test the proposed matching strategies in the study area of Metropolitan Melbourne,Australia.The proposed strategies outperform the original MATSim strategies(which follow a first-come,first-serve approach)regarding average vehicle kilometers traveled(VKT)per ride,number of multimodal trips that use ride-hailing and PT,and the overall PT mode share.The results indicate substantial improvements across all proposed strategies,with PT mode shares increasing by 3.3%–19.8%.A fleet size of 200 was identified as the optimal fleet size.Multimodal trips increased by 7%–13%for all proposed strategies at this fleet size,illustrating a substantial shift towards integrated transport modes.Additionally,VKT per ride decreased by approximately 30%–33%with the proposed strategies at this fleet size.We conclude that serving all ride-hailing requests on a first-come/first-serve basis creates system-level inefficiencies that can be overcome by prioritizing requests that cannot be served by PT and/or have an emergency nature.展开更多
Unexpected scenarios often occur during typhoon response,which is likely to cause the failure of evacuation vehicle dispatching and other preparedness plans.To solve this problem,a vehicle dispatching plan selecting m...Unexpected scenarios often occur during typhoon response,which is likely to cause the failure of evacuation vehicle dispatching and other preparedness plans.To solve this problem,a vehicle dispatching plan selecting method based on fault-tolerance analysis is proposed,which considers the bounded rationality of emergency decision-makers.The method improves the capability of responding to unexpected scenarios by increasing backup resources.First,under the expected scenarios,a bi-level programming model for arranging the quantities of each type of vehicle and their routes is established,with the goal of minimizing the expected total evacuation time.A corresponding solving algorithm is designed.Second,possible unexpected scenarios are preset by integrating local and non-local historical experiences,and the scenario influences on vehicle dispatching constraints are analyzed.Third,under unexpected scenarios,a fault-tolerance plan set is established considering the failure risk of vehicle dispatching and fault-tolerant cost.The optimal plan is selected by calculating and ranking fault-tolerant rates.Finally,a case study in Shenzhen,China is provided to verify the reasonability and effectiveness of the method.The results show that the proposed method can help discover and address the‘fault’of vehicle dispatching plans during emergency preparedness and thus improve evacuation capabilities in emergency response.The proposed method can be used to develop evacuation vehicle dispatching planning methods with comprehensive scenario adaptability and a precisely improved capability.展开更多
The city-wide ridesharing package delivery is becoming popular as it provides a convenience such as extra profits to the vehicle’s driver and high traffic efficiency to the city.The vehicle dispatching is a significa...The city-wide ridesharing package delivery is becoming popular as it provides a convenience such as extra profits to the vehicle’s driver and high traffic efficiency to the city.The vehicle dispatching is a significant issue to improve the ridesharing efficiency in package delivery.The classic one-hop ridesharing package delivery requires the highly similar paths between the package and the vehicle given by the limited detour time,which depresses the ridesharing efficiency.To tackle this problem,a city-wide vehicle dispatching strategy for the multi-hop ridesharing package delivery was proposed,where a package is permitted to be delivered sequentially by different vehicles,until arriving the destination.The study formulates the vehicle dispatching as a maximum multi-dimensional bipartite matching problem with the goal of maximizing the total saving distance given by the limited detour time and ridesharing capacity.A multi-hop ridesharing vehicle dispatching algorithm was proposed to solve this problem by selecting the farthest reachable locker and multi-dimensional matching.Simulation results based on real vehicle dataset of Beijing demonstrate the effectiveness and efficiency of the proposed vehicle dispatching strategy.展开更多
In recent years,multiple-load automatic guided vehicle(AGV)is increasingly used in the logistics transportation fields,owing to the advantages of smaller fleet size and fewer occurrences of traffic congestion.However,...In recent years,multiple-load automatic guided vehicle(AGV)is increasingly used in the logistics transportation fields,owing to the advantages of smaller fleet size and fewer occurrences of traffic congestion.However,one main challenge lies in the deadlock-avoidance for the dispatching process of a multiple-load AGV system.To prevent the system from falling into a deadlock,a strategy of keeping the number of jobs in the system(NJIS)at a low level is adopted in most existing literatures.It is noteworthy that a low-level NJIS will make the processing machine easier to be starved,thereby reducing the system efficiency unavoidably.The motivation of the paper is to develop a deadlock-avoidance dispatching method for a multiple-load AGV system operating at a high NJIS level.Firstly,the deadlock-avoidance dispatching method is devised by incorporating a deadlock-avoidance strategy into a dispatching procedure that contains four sub-problems.In this strategy,critical tasks are recognized according to the status of workstation buffers,and then temporarily forbidden to avoid potential deadlocks.Secondly,three multiattribute dispatching rules are designed for system efficiency,where both the traveling distance and the buffer status are taken into account.Finally,a simulation system is developed to evaluate the performance of the proposed deadlock-avoidance strategy and dispatching rules at different NJIS levels.The experimental results demonstrate that our deadlock-avoidance dispatching method can improve the system efficiency at a high NJIS level and the adaptability to various system settings,while still avoiding potential deadlocks.展开更多
We describe a system for turning the accumulator electric locomotives used in coal mines. This improves transport efficiency and decreases mine construction and production costs. The operating requirements, principles...We describe a system for turning the accumulator electric locomotives used in coal mines. This improves transport efficiency and decreases mine construction and production costs. The operating requirements, principles, working features and transmission system are discussed. This system has a simple structure and can be manufactured, transported and assembled easily. It, therefore, can handle accumulator locomotives of middle and small size.展开更多
文摘Operational strategies and matching algorithms are used to ensure the availability and efficient assignment of ride-hailing services.Such operational strategies may result in services that,rather than complement traditional public transport(PT)systems,compete with them in both market(demand)and road-space use(congestion).This paper introduces and evaluates real-time vehicle dispatching strategies that focus on the prioritization of PT use and the complementarity between PT and ride-hailing in multimodal trips.Utilizing a novel two-step ride-matching algorithm,these strategies aim at decreasing travelers'wait times and motivating the use of PT.The agent-based travel demand forecasting model MATSim is used to implement and test the proposed matching strategies in the study area of Metropolitan Melbourne,Australia.The proposed strategies outperform the original MATSim strategies(which follow a first-come,first-serve approach)regarding average vehicle kilometers traveled(VKT)per ride,number of multimodal trips that use ride-hailing and PT,and the overall PT mode share.The results indicate substantial improvements across all proposed strategies,with PT mode shares increasing by 3.3%–19.8%.A fleet size of 200 was identified as the optimal fleet size.Multimodal trips increased by 7%–13%for all proposed strategies at this fleet size,illustrating a substantial shift towards integrated transport modes.Additionally,VKT per ride decreased by approximately 30%–33%with the proposed strategies at this fleet size.We conclude that serving all ride-hailing requests on a first-come/first-serve basis creates system-level inefficiencies that can be overcome by prioritizing requests that cannot be served by PT and/or have an emergency nature.
基金supported by the Young Scientists Fund of the National Natural Science Foundation of China(No.72404232)the Major Research Project of National Natural Science Foundation of China named“Big data Driven Management and Decision-making Research”(No.91746207)Fujian Provincial Natural Science Foundation(No.2023J05011).
文摘Unexpected scenarios often occur during typhoon response,which is likely to cause the failure of evacuation vehicle dispatching and other preparedness plans.To solve this problem,a vehicle dispatching plan selecting method based on fault-tolerance analysis is proposed,which considers the bounded rationality of emergency decision-makers.The method improves the capability of responding to unexpected scenarios by increasing backup resources.First,under the expected scenarios,a bi-level programming model for arranging the quantities of each type of vehicle and their routes is established,with the goal of minimizing the expected total evacuation time.A corresponding solving algorithm is designed.Second,possible unexpected scenarios are preset by integrating local and non-local historical experiences,and the scenario influences on vehicle dispatching constraints are analyzed.Third,under unexpected scenarios,a fault-tolerance plan set is established considering the failure risk of vehicle dispatching and fault-tolerant cost.The optimal plan is selected by calculating and ranking fault-tolerant rates.Finally,a case study in Shenzhen,China is provided to verify the reasonability and effectiveness of the method.The results show that the proposed method can help discover and address the‘fault’of vehicle dispatching plans during emergency preparedness and thus improve evacuation capabilities in emergency response.The proposed method can be used to develop evacuation vehicle dispatching planning methods with comprehensive scenario adaptability and a precisely improved capability.
基金the National Natural Science Foundation of China(61701037)the National Undergraduate Innovation and Entrepreneurship Taining Program。
文摘The city-wide ridesharing package delivery is becoming popular as it provides a convenience such as extra profits to the vehicle’s driver and high traffic efficiency to the city.The vehicle dispatching is a significant issue to improve the ridesharing efficiency in package delivery.The classic one-hop ridesharing package delivery requires the highly similar paths between the package and the vehicle given by the limited detour time,which depresses the ridesharing efficiency.To tackle this problem,a city-wide vehicle dispatching strategy for the multi-hop ridesharing package delivery was proposed,where a package is permitted to be delivered sequentially by different vehicles,until arriving the destination.The study formulates the vehicle dispatching as a maximum multi-dimensional bipartite matching problem with the goal of maximizing the total saving distance given by the limited detour time and ridesharing capacity.A multi-hop ridesharing vehicle dispatching algorithm was proposed to solve this problem by selecting the farthest reachable locker and multi-dimensional matching.Simulation results based on real vehicle dataset of Beijing demonstrate the effectiveness and efficiency of the proposed vehicle dispatching strategy.
基金supported by the National Natural Science Foundation of China(Nos.52005427,61973154)the National Defense Basic Scientific Research Program of China(No.JCKY2018605C004)+1 种基金the Natural Science Research Project of Jiangsu Higher Education Institutions(Nos.19KJB510013,18KJA460009)the Foundation of Graduate Innovation Center in Nanjing University of Aeronautics and Astronautics(No.KFJJ20190516)。
文摘In recent years,multiple-load automatic guided vehicle(AGV)is increasingly used in the logistics transportation fields,owing to the advantages of smaller fleet size and fewer occurrences of traffic congestion.However,one main challenge lies in the deadlock-avoidance for the dispatching process of a multiple-load AGV system.To prevent the system from falling into a deadlock,a strategy of keeping the number of jobs in the system(NJIS)at a low level is adopted in most existing literatures.It is noteworthy that a low-level NJIS will make the processing machine easier to be starved,thereby reducing the system efficiency unavoidably.The motivation of the paper is to develop a deadlock-avoidance dispatching method for a multiple-load AGV system operating at a high NJIS level.Firstly,the deadlock-avoidance dispatching method is devised by incorporating a deadlock-avoidance strategy into a dispatching procedure that contains four sub-problems.In this strategy,critical tasks are recognized according to the status of workstation buffers,and then temporarily forbidden to avoid potential deadlocks.Secondly,three multiattribute dispatching rules are designed for system efficiency,where both the traveling distance and the buffer status are taken into account.Finally,a simulation system is developed to evaluate the performance of the proposed deadlock-avoidance strategy and dispatching rules at different NJIS levels.The experimental results demonstrate that our deadlock-avoidance dispatching method can improve the system efficiency at a high NJIS level and the adaptability to various system settings,while still avoiding potential deadlocks.
文摘We describe a system for turning the accumulator electric locomotives used in coal mines. This improves transport efficiency and decreases mine construction and production costs. The operating requirements, principles, working features and transmission system are discussed. This system has a simple structure and can be manufactured, transported and assembled easily. It, therefore, can handle accumulator locomotives of middle and small size.
