scholarly journals Urban Rail Timetable Optimization to Improve Operational Efficiency with Flexible Routing Plans: A Nonlinear Integer Programming Model

2019 ◽  
Vol 11 (13) ◽  
pp. 3701 ◽  
Author(s):  
Qiuchi Xue ◽  
Xin Yang ◽  
Jianjun Wu ◽  
Huijun Sun ◽  
Haodong Yin ◽  
...  
Keyword(s):  
Integer Programming ◽  
Waiting Time ◽  
Optimization Model ◽  
Programming Model ◽  
Urban Rail Transit ◽  
Nonlinear Integer Programming ◽  
Load Factor ◽  
Integer Programming Model ◽  
Passenger Flow ◽  
Urban Rail

At present, most urban rail transit systems adopt an operation mode with a single long routing. The departure frequency is determined by the maximum section passenger flow. However, when the passenger flow varies greatly within different sections, this mode will lead to a low load factor in some sections, resulting in a waste of capacity. In view of this situation, this paper develops a nonlinear integer programming model to determine an optimal timetable with a balanced scheduling mode, where the wasted capacity at a constant departure frequency can be reduced with a slight increase in passenger waiting time. Then, we simplify the original model into a single-objective integer optimization model through normalization. A genetic algorithm is designed to find the optimal solution. Finally, a numerical example is presented based on real-world passenger and operation data from Beijing Metro Line 4. The results show that the double-routing optimization model can reduce wasted capacity by 9.5%, with a 4.5% increase in passenger waiting time, which illustrates the effectiveness of this optimization model.

Collaborative passenger flow control of urban rail transit network considering balanced distribution of passengers

2021 ◽  
pp. 2150461
Author(s):  
Xiang Li ◽  
Yan Bai ◽  
Kaixiong Su
Keyword(s):  
Flow Control ◽  
Programming Model ◽  
Flow Characteristics ◽  
Service Level ◽  
Urban Traffic ◽  
Urban Rail Transit ◽  
Control Measures ◽  
Rail Transit ◽  
Passenger Flow ◽  
Urban Rail

The increase of urban traffic demands has directly affected some large cities that are now dealing with more serious urban rail transit congestion. In order to ensure the travel efficiency of passengers and improve the service level of urban rail transit, we proposed a multi-line collaborative passenger flow control model for urban rail transit networks. The model constructed here is based on passenger flow characteristics and congestion propagation rules. Considering the passenger demand constraints, as well as section transport and station capacity constraints, a linear programming model is established with the aim of minimizing total delayed time of passengers and minimizing control intensities at each station. The network constructed by Line 2, Line 6 and Line 8 of the Beijing metro is the study case used in this research to analyze control stations, control durations and control intensities. The results show that the number of delayed passengers is significantly reduced and the average flow control ratio is relatively balanced at each station, which indicates that the model can effectively relieve congestion and provide quantitative references for urban rail transit operators to come up with new and more effective passenger flow control measures.

scholarly journals A Nonlinear Integer Programming Model for Integrated Location, Inventory, and Routing Decisions in a Closed-Loop Supply Chain

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-17 ◽  
Author(s):  
Hao Guo ◽  
Congdong Li ◽  
Ying Zhang ◽  
Chunnan Zhang ◽  
Yu Wang
Keyword(s):  
Supply Chain ◽  
Integer Programming ◽  
Facility Location ◽  
Vehicle Routing ◽  
Closed Loop ◽  
Programming Model ◽  
Nonlinear Integer Programming ◽  
Inventory Routing ◽  
Closed Loop Supply Chain ◽  
Integer Programming Model

Facility location, inventory management, and vehicle routing are three important decisions in supply chain management, and location-inventory-routing problems consider them jointly to improve the performance and efficiency of today’s supply chain networks. In this paper, we study a location-inventory-routing problem to minimize the total cost in a closed-loop supply chain that has forward and reverse logistics flows. First, we formulate this problem as a nonlinear integer programming model to optimize facility location, inventory control, and vehicle routing decisions simultaneously in such a system. Second, we develop a novel heuristic approach that incorporates simulated annealing into adaptive genetic algorithm to solve the model efficiently. Last, numerical analysis is presented to validate our solution approach, and it also provides meaningful managerial insight into how to improve the closed-loop supply chain under study.

scholarly journals A Timetable Optimization Model for Urban Rail Transit with Express/Local Mode

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Renjie Zhang ◽  
Shisong Yin ◽  
Mao Ye ◽  
Zhiqiang Yang ◽  
Shanglu He
Keyword(s):  
Waiting Time ◽  
Optimization Model ◽  
Urban Rail Transit ◽  
Local Mode ◽  
Rail Transit ◽  
Long Distance ◽  
Urban Rail ◽  
Proposed Model ◽  
Distance Travel ◽  
Timetable Optimization

Nowadays, an express/local mode has be studied and applied in the operation of urban rail transit, and it has been proved to be beneficial for the long-distance travel. The optimization of train patterns and timetables is vital in the application of the express/local mode. The former one has been widely discussed in the various existing works, while the study on the timetable optimization is limited. In this study, a timetable optimization model is proposed by minimizing the total passenger waiting time at platforms. Further, a genetic algorithm is used to solve the minimization problems in the model. This study uses the data collected from Guangzhou Metro Line 14 and finds that the total passenger waiting time at platforms is reduced by 9.3%. The results indicate that the proposed model can reduce the passenger waiting time and improve passenger service compared with the traditional timetable.

Paratransit Service Optimization for Special Events

2005 ◽  
Vol 1903 (1) ◽  
pp. 64-77
Author(s):  
Matthew G. Karlaftis ◽  
Konstantinos L. Kepaptsoglou ◽  
Antony Stathopoulos
Keyword(s):  
Integer Programming ◽  
Travel Time ◽  
Programming Model ◽  
Nonlinear Integer Programming ◽  
Time Constraints ◽  
Microsoft Excel ◽  
Integer Programming Model ◽  
Special Events ◽  
User Friendly ◽  
Service Optimization

Paratransit services can be useful for special events, especially when private vehicles are discouraged from approaching the event locations. During the Athens 2004 Olympics, such a shuttle service was planned to connect major Athens spots with athletic complexes. A mixed nonlinear integer programming model is developed for jointly obtaining optimal headways and vehicle types for such a paratransit service, given demand, resource, and travel time constraints. The model is incorporated into a user-friendly Microsoft Excel–based interface. An application of the model to the Athens 2004 Olympics and its results are presented and discussed.

scholarly journals Modeling and Optimization of Collaborative Passenger Control in Urban Rail Stations under Mass Passenger Flow

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Lili Wang ◽  
Xuedong Yan ◽  
Yun Wang
Keyword(s):  
Programming Model ◽  
Rapid Development ◽  
Urban Rail Transit ◽  
Control Measures ◽  
Target Station ◽  
Passenger Flow ◽  
Urban Rail ◽  
Entire Line ◽  
Passenger Flows ◽  
The One

With the rapid development of urban rail transit, the phenomenon of outburst passenger flows flocking to stations is occurring much more frequently. Passenger flow control is one of the main methods used to ensure passengers’ safety. While most previous studies have only focused on control measures inside the target station, ignoring the collaboration between stops, this paper puts emphasis on joint passenger control methods during the occurrence of large passenger flows. To provide a theoretic description for the problem under consideration, an integer programming model is built, based on the analysis of passenger delay and the processes by which passengers alight and board. Taking average passenger delay as the objective, the proposed model aims to disperse the pressure of oversaturated stations into others, achieving the optimal state for the entire line. The model is verified using a case study and the results show that restricted access measures taken collaboratively by stations produce less delay and faster evacuation. Finally, a sensitivity analysis is conducted, from which we find that the departure interval and maximum conveying capacity of the train affect passenger delay markedly in the process of passenger control and infer that control measures should be taken at stations near to the one experiencing an emergency.

Emergency evacuation with unbalanced utilization of exits atplatform level: A simulation study

2021 ◽  
pp. 1-9
Author(s):  
Hongxu Chen ◽  
Xingjian Huang ◽  
Huan Li ◽  
Haibo Zhang
Keyword(s):  
Optimization Model ◽  
Three Dimensional ◽  
Emergency Evacuation ◽  
Urban Rail Transit ◽  
Utilization Rate ◽  
Evacuation Time ◽  
Passenger Flow ◽  
Urban Rail ◽  
Depth Analysis ◽  
Dimensional Simulation

Urban rail transit station has a large number of people gathering and relatively closed space, which has become a high incidence of emergencies. In the process of emergency evacuation, due to the unbalanced utilization rate of exits, the evacuation time is prolonged, which seriously threatens the safety of people in the station. In order to find out the reasons for the imbalance of the utilization rate of the exit, and put forward the solution, balance the utilization rate of each exit, improve the evacuation efficiency. In this paper, a subway station platform in Southwest China is taken as an example to establish a three-dimensional simulation model by using anylogic software. Through in-depth analysis, it is found that the reason for the unbalanced utilization of the platform floor exit is that the number of evacuation people at each exit does not match the evacuation capacity. According to the analysis results, the optimization model is put forward. Through comparative analysis, it is found that the optimization model can effectively balance the export utilization rate. Under the current conditions of off peak passenger flow, peak passenger flow and long-term peak passenger flow, the evacuation time can be saved by more than 20%.

scholarly journals Equity-Oriented Train Timetabling with Collaborative Passenger Flow Control: A Spatial Rebalance of Service on an Oversaturated Urban Rail Transit Line

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Chaoqi Gong ◽  
Baohua Mao ◽  
Min Wang ◽  
Tong Zhang
Keyword(s):  
Flow Control ◽  
Programming Model ◽  
Optimal Solution ◽  
Urban Rail Transit ◽  
Mixed Integer ◽  
Rail Transit ◽  
Optimization Approach ◽  
Train Timetabling ◽  
Passenger Flow ◽  
Urban Rail

On an oversaturated urban rail transit line, passengers at downstream stations have to wait for more trains until they get aboard, resulting in service imbalance problem. To improve the service quality, this paper proposes an integrated optimization approach combining the train timetabling and collaborative passenger flow control, with the aim of minimizing indicators associated with the passenger service imbalance and train loading capacity utilization. Considering train regulation constraints and passenger loading dynamics, a mixed-integer linear programming model is formulated. Based on the linear weighting technique, an iterative heuristic algorithm combining the tabu search and Gurobi solver is designed to solve the proposed model. Finally, a simple case with different-scale instances is used to verify that the proposed algorithm can obtain near-optimal solution efficiently. Moreover, a real-world case of Beijing Subway Batong Line is implemented to compare performances of the proposed approach with those under the original timetable and noncollaborative passenger flow control.

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