Seminar: The Static Multi-Vehicle Bike Repositioning Problem


             Department of Systems Engineering and Engineering Management
                     The Chinese University of Hong Kong


Date:Thursday,January 21, 2021, 17:30 to 18:30

Title: The Static Multi-Vehicle Bike Repositioning Problem

Speaker: Professor Wai Yuen Szeto, The University of Hong Kong


This study investigates a static Bike Repositioning Problem (BRP) that determines the routes of repositioning vehicles and the loading and unloading quantities at each bike station to firstly minimize the positive deviation from the Tolerance of total Demand Dissatisfaction (TDD) and then service time. The total demand dissatisfaction of a bike-sharing system in this study is defined as the sum of the difference between the bike deficiency and unloading quantity of each station in the system. Two service times are considered: the total service time and the maximum route duration of the fleet. To reduce the computation time to solve the loading and unloading sub-problem of the BRP, this study examines a novel set of loading and unloading strategies and further proves them to be optimal for a given route. This set of strategies is then embedded into an enhanced artificial bee colony algorithm to solve the BRP. The numerical results demonstrate that a larger fleet size may not lead to a lower total service time but can effectively lead to a lower maximum route duration at optimality. The results also illustrate the trade-offs between the two service times, between total demand dissatisfaction and total service time, and between the number of operating vehicles provided and the TDD. Moreover, the results demonstrate that the optimal values of the two service times can increase with the TDD and introducing an upper bound on one service time can reduce the optimal value of the other service time.


Dr. Wai Yuen Szeto is a Professor and an Associate Head at the Department of Civil Engineering at The University of Hong Kong, and the Deputy Director of the Institute of Transport Studies at that university. He is a Top 1 % Scholar 2015-2020 (according to Clarivate Analytics' Essential Science Indicators). His current h-index is 52 (Google scholar). He is an author of over 150 refereed journal papers, with two papers in Operations Research and 33 papers in Transportation Research Part B. His publications have been cited over 7470 times (Google scholar).  The publications are related to shared mobility, dynamic traffic assignment, transport network design, public transport, network reliability, game-theoretic approaches to transport and logistics problems, modeling land use, transport and environment interaction, and sustainable transport. He received the World Conference on Transport Research Prize (2001), the Eastern Asia Society for Transportation Studies Outstanding Paper Award (2003), the Hong Kong Society for Transportation Studies Outstanding Dissertation Paper Award and the Gordon Newell Memorial Prize (2005), the Hong Kong Institution of Engineers Outstanding Paper Award for Young Engineers/Researchers (2008), the Best Paper Award of the 10th International Workshop on Computational Transportation Science (2018), and the Outstanding Paper Award of the 2018 China Urban Transportation Planning Annual Meeting. He also received the Certificate of Excellence in Reviewing from Transportation Research Part B in 2013 and Transportation Research Part C in 2013 and 2016. Currently, he is an Editor of Transportmetrica B, an Associate Editor of Transportation Research Part D and E, Journal of Intelligent Transportation Systems, Transportmetrica A, Travel Behaviour and Society, an Area Editor of Networks and Spatial Economics, and an Editorial Board Member of Transportation Research Part C, and International Journal of Sustainable Transportation. 


Thursday, January 21, 2021 - 17:30 to 18:30