On March 3, 2023, at the invitation of the Faculty of Business and Management (FBM), Professor Zizhuo Wang delivered a distinguished lecture titled "Assign-to-Seat: Dynamic Capacity Control for Selling High-Speed Train Tickets". Professor Steve WB Liu, Dean of FBM gave a welcome speech and presented a souvenir to Professor Wang.

Prof. Steve Liu (Dean of FBM) Presented Souvenir to Prof. Wang

Prof. Zizhuo Wang is a Professor and Associate Dean at the School of Data Science. He is also the co-founder and CTO of Cardinal Operations (杉数科技). He obtained his bachelor's degree in Mathematics from Tsinghua University in 2007, and his Ph.D. degree in Operations Research from Stanford University in 2012. Prior to joining CUHK-Shenzhen, he was an Associate Professor (with tenure) in the Department of Industrial and Systems Engineering at the University of Minnesota.

The seminar consists of two parts.

In the first part, Prof. Wang presented his recent research "Assign-to-Seat: Dynamic Capacity Control for Selling High-Speed Train Tickets". He began with an example of a common high-speed railway in China and encouraged the audience to make assumptions about seat assignments. In this way, he led to motivations and research questions aimed at investigating how to make the railway system more efficient, and whether seat assignment might affect the efficiency of the whole system. Prof. Wang presented the problem as a static problem, identified the problem as NP-hard in general, and determined that the problem is polynomially solvable.

Prof. Wang then proposed the problem as a dynamic problem (DP), which proved to be challenging to solve directly. Prof. Wang demonstrated 4 policies for solving the dynamic problem , including: 1) Static Booking Limit Control (SBLC) Policy; 2).Bid-Price Policy based on Static Model (BP-S); 3) Bid-Price Policy based on Maximal Sequence (BP-M), which accommodates nonlinearity in bid prices and yields a more accurate approximation of the value function than a traditional bid-price control policy; 4)"Re-solving a Dynamic Primal" Policy, which combines a dynamic view of the maximal sequence with the static solution of a primal problem to achieve uniformly bounded revenue loss under mild assumptions. The policies were progressively improved based on the former one, and the most effective policies were found to be the BP-M and RDP policies.

For the numerical experiments, Prof Wang and his colleagues work with the China Railway High Speed Railway Bureau to verify their policies by obtaining real booking data. They used both synthetic and real data, which showed that the policies improved the efficiency of capacity allocation and provided a significant advantage.

Prof. Wang's research provides new insights into the optimization of high-speed railway ticket sales and highlights the potential benefits of using dynamic programming to solve complex problems. The research could have significant implications for the management of high-speed railway systems worldwide and contribute to the development of more efficient and cost-effective transportation systems.

Prof. Wang’s lecture

During the Q&A session, FBM Dean Prof. Liu asked whether the suggested policies have been implemented in practice.“Not yet. But we hope this gives some guidance.”answered Prof. Wang. Then an audience asked Prof. Wang,“What is your purpose of using both primal and dual in dealing with linear programming?”.“They are two sides of the same problem and both can get a good solution.” said Prof. Wang,“The primal level is more like a capacity reservation while dual refers to a value-based approach.”

In the second part, Prof. Wang then shared information about Cardinal Operations(杉数科技) and industry trends. The company aims to provide data-driven decision support services and products to the Chinese industry through the use of smart enterprise operations. They developed a mathematical optimization solver (COPT solver) for large-scale optimization problems, which serves over 200 enterprises. The solver optimizes decision-making in several industries (retail, industrial manufacture, infrastructure and etc). Prof Wang's presentation inspired UIC students to take a broader perspective on industry trends and future careers. The audience greatly benefited, and the lecture ended with warm applause.

Audience on-site