有桩自行车共享系统吞吐率的近似模型及算法  

An approximate model and algorithm for throughput rate of a docked bike-sharing system

作　　者：王静妍 张勇 WANG Jingyan;ZHANG Yong(School of Rail Transportation,Soochow University,Suzhou 215131,China)

机构地区：[1]苏州大学轨道交通学院,江苏苏州215131

出　　处：《山东科学》2023年第6期74-85,共12页Shandong Science

基　　金：国家自然科学基金(52002261);国家社科基金重大项目(13&ZD175)。

摘　　要：通过探讨用户需求和骑行时间不确定的有桩自行车共享系统(docked bike-sharing system,DBSS)建立吞吐率的近似模型及算法。一个具有固定自行车数量的DBSS可视为封闭的排队网络,每个站点都是有限的M/M/1队列,由此建立了DBSS吞吐率的近似模型及其算法。该算法不仅能够计算道路上期望的自行车数量、骑行时间、车站的期望库存及停留时间,还能计算最优自行车投放量,即吞吐率最大值对应的最小的自行车投放量。同时,给出了给定用户需求、路由矩阵和车桩分配下站点自行车集聚与空缺的判断方法。将该近似算法在真实的DBSS中进行了应用。结果表明,随着自行车投放量的增加,系统吞吐率呈阶梯形递增但存在上限;自行车投放量一旦超过最优数量将产生闲置,并且自行车集聚与空缺站点分布也将固定。In this paper,an approximate model and algorithm for the throughput rate are established by studying a docked bike-sharing system(DBSS)using stochastic user demands,routing matrix,and cycling times.A DBSS with a fixed number of bikes can be considered a closed queuing network with a buffered M/M/1 queue at each station,thus establishing an approximate model and algorithm for the throughput rate of DBSS.This algorithm can calculate the average number of bikes on roads and at stations.Moreover,it can estimate the average cycling time on roads and bike dwell time at stations and further determine the optimal number of bikes achieving the maximum throughput rate in the DBSS.Additionally,this paper proposes a method to determine whether a station is a bike surplus station or a bike deficient station under given user demands,routing matrix,cycling time matrix,and dock allocation.Finally,the approximate algorithm is verified in a real-world DBSS.The results show that the throughput rate of the DBSS increases in a step-wise manner with the increasing bike input under an superior limit.When the number of bike inputs exceeds the optimal quantity,there will be idle bikes,and the spatial distribution of bike surplus stations and bike deficient stations will remain unchanged.

关 键 词：有桩自行车共享系统 运营效率 封闭排队网络 吞吐率 空满桩站点 自行车投放量 

分 类 号：U491[交通运输工程—交通运输规划与管理]