Title: Repositioning in bike sharing systems with broken bikes considering on-site repairs
Speaker: Mr. Runqiu Hu (Department of Civil Engineering)
Date: Jun 30, 2025 (Monday)
Time: 2:00 pm - 3:00 pm
Venue: Room 612B, 6/F, Haking Wong Building, The University of Hong Kong
About the talk: This research introduces a novel approach to bike-sharing system operations by simultaneously considering both vehicle-based repositioning and on-site repairs of broken bikes. While existing studies have typically assumed broken bikes can only be repaired at depots after collection, this research recognizes that bike-sharing operators also dispatch repairers for on-site repairs, satisfying demand without vehicle repositioning. A mixed-integer linear programming model is developed for a static bike repositioning problem combining vehicle-based delivery/collection with labor-based on-site repairs, aimed at minimizing the total cost of user dissatisfaction and carbon emissions within a specified time budget. For efficient solution of this complex problem, a hybrid algorithm is proposed incorporating Genetic Search with Adaptive Diversity Control and a novel Station Budget Constrained heuristic, which limits time spent at each station based on benefit-cost ratios. Computational experiments demonstrate that the algorithm obtains optimal solutions for small instances and outperforms commercial solvers on larger networks with less computational time. The cost-effectiveness of deploying repairers is examined, revealing diminished effectiveness with longer repair times and lower percentages of broken bikes. These findings highlight the need for dynamic repairer allocation based on the system's actual damage level, suggesting preventive maintenance strategies can reduce both broken bikes and repair time. The study contributes to the understanding of how on-site repairs can be integrated with traditional repositioning methods in bike-sharing systems.
About the speaker: Mr. Runqiu Hu is currently a Ph.D. student in the Department of Civil Engineering at The University of Hong Kong, supervised by Prof. W.Y. Szeto. He received his bachelor’s degree in Cybersecurity from the Department of Computer Science, Nanjing University of Posts and Telecommunications in 2018 and master’s degree in Computer Technology from the School of Computer Science and Engineering, Southeast University, China, in 2021. His research interests include shared mobility systems, transportation optimization, multi-objective optimization, and the application of artificial intelligence in transportation engineering. Runqiu has publications in several journals including Transportation Research Part E, Transportation Research Part D, IEEE Internet of Things Journal, and IEEE Access. His work focuses on bike-sharing system operations, electric vehicle range anxiety analysis, and intelligent transportation optimization. During his master’s study, he developed expertise in knowledge representation and reasoning, particularly in non-monotonic reasoning for decision support systems using answer set programming and finding reasoning paths for the explainable AI. His current research explores the integration of operations research techniques with transportation engineering challenges, with a specific emphasis on developing efficient algorithms for complex optimization problems in shared mobility contexts.