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Title: Uncertainty Estimation of the Connected Vehicle Penetration Rate: Modeling Complex Residual-vehicle Effects

Speaker: Mr. Shaocheng Jia (Department of Civil Engineering)

Date: September 27, 2024 (Friday)

Time: 10:00 am - 11:00 am

Venue: Room 612B, 6/F, Haking Wong Building, The University of Hong Kong


About the talk: In the transition to full deployment of connected vehicles (CVs), the CV penetration rate plays a key role in bridging the gap between partial and complete traffic information. Several innovative methods have been proposed to estimate the CV penetration rate using only CV data. However, these methods, as point estimators, may lead to biased estimations or suboptimal solutions when applied directly in modeling or system optimization. To avoid these problems, the uncertainty and variability in the CV penetration rate must be considered. Recently, a probabilistic penetration rate (PPR) model was developed for estimating such uncertainties. The key model input is a constrained queue length distribution composed exclusively of queues formed by red signals in undersaturation conditions with no residual vehicles. However, in real-world scenarios, due to random arrivals, residual vehicles are commonly carried over from one cycle to another in temporary overflow cycles in undersaturation conditions, which seriously restricts the applicability of the PPR model. To address this limitation, this talk will introduce a Markov-constrained queue length (MCQL) model that can model the complex effects of residual vehicles on the CV penetration rate uncertainty. Comprehensive VISSIM simulations and applications to real-world datasets demonstrate that the proposed MCQL model can accurately model the residual-vehicle effect and estimate the uncertainty. Thus, the applicability of the PPR model is truly extended to real-world settings, regardless of the presence of residual vehicles. A simple stochastic CV-based adaptive signal control example illustrates the potential of the proposed model in real-world applications.


About the speaker: Shaocheng Jia is currently a Ph.D. candidate at The University of Hong Kong and a (student) member of IEEE, IEEE ITSS, INFORMS, INFORMS TSL, CHTS, IACIP, and ITS of HKU. He received his B.E. degree from the Department of Electronic Information Engineering, China University of Petroleum (Beijing), and M.E. degree from the Department of Automation, Tsinghua University, in 2014 and 2018, respectively. His research interests include intelligent perception and control, connected and automated transportation, stochastic modeling and optimization, and machine learning. Shaocheng has published over 10 papers in prestigious journals and conferences, including Transportation Science, IEEE TITS, TR-Part C, the International Symposium on Transportation and Traffic Theory (ISTTT), etc., as well as 6 national invention patents. Shaocheng is also a recipient of the Outstanding Master’s Dissertation Awards from CHTS and Tsinghua University. He has chaired a regular session in the 26th IEEE ITSC and a Young Scholar Tech Talk at HKU, co-organized two workshops in IEEE ITSC, and been a reviewer for IEEE TITS, IEEE TNNLS, IEEE TMC, TRR, IEEE ITSC, TRB, etc.

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Cognitive Hierarchy in Day-to-day Network Flow Dynamics


Speaker:

Prof. Feng Xiao

Business School, Sichuan University, China

Date:    Nov. 01, 2024 (Friday)

Time:   3:00pm – 4:00pm

Venue:  Room 612B, 6/F Haking Wong Building, The University of Hong Kong


Abstract

When making route decisions, travelers may engage in a certain degree of reasoning about what the others will do in the upcoming day, rendering yesterday’s shortest routes less attractive. This phenomenon was manifested in a recent virtual experiment that mimicked travelers’ repeated daily trip-making process. Unfortunately, prevailing day-to-day traffic dynamical models failed to faithfully reproduce the collected flow evolution data therein. To this end, we propose a day-to-day traffic behavior modeling framework based on the Cognitive Hierarchy theory, in which travelers with different levels of strategic-reasoning capabilities form their own beliefs about lower-step travelers’ capabilities when choosing their routes. Two widely studied day-to-day models, the Network Tatonnement Process dynamic and the Logit dynamic, are extended into the framework and studied as examples. Calibration of the virtual experiment is performed using the extended Network Tatonnement Process dynamic, which fits the experimental data reasonably well. We show that the two extended dynamics have multiple equilibria, one of which is the classical user equilibrium. While analyzing global stability is intractable due to the presence of multiple equilibria, local stabilities near equilibria are developed analytically and verified by numerical experiments. General insights on how key parameters affect the stability of user equilibria are unveiled.


About the Speaker

Feng Xiao is currently a professor at Business School of Sichuan University, recipient of the National Science Fund for Distinguished Young Scholars, China. Dr. Xiao’s research interests include artificial intelligence algorithms and data mining, modeling and optimization of complex traffic systems, financial risk management and quantitative trading, healthcare data management, etc. He has published more than 70 papers in internationally renowned journals and conferences in the fields of management science and engineering, transportation technology and data mining, such as Transportation Science, Transportation Research Part A, B, C, D, E, IEEE TKDE, ISTTT, etc.

 

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Large Deployment of Connected Vehicles in Australia


Speaker:

Prof. Majid Sarvi

Melbourne School of Engineering, University of Melbourne, Australia

Date:    September 6, 2024 (Friday)

Time:   11:00 am – 12:00 pm

Venue:  Room 612B, 6/F Haking Wong Building, The University of Hong Kong


Abstract

Co-operative Intelligent Transport Systems (C-ITS) technology enables road users and infrastructure to communicate with each other, sharing information about road conditions, disruptions, traffic flow and safety incidents. C-ITS has been proven to have the potential to provide significant safety benefits by detecting and providing advanced warning to drivers to prevent incidents and improve efficiency of transport networks. C-ITS needs alignment amongst governments and industry for deployment to realise these benefits. We have embarked on an ambition project which involves uplifting around 30 intersections across five key corridors in Melbourne busy urban environment with the advanced sensing and communication capability to continually transmit live information about traffic and safety for road users. Deploying C-ITS at scale in a real-world environment. This will allow assessment of proposed benefits, deployment considerations and options, and provide recommendations that could support Australia’s road authorities’ adoption of C-ITS in a nationally harmonised manner.


About the Speaker

Professor Sarvi is the chair in transport engineering and the director of Transport Technology program at the University of Melbourne. He is the founder and director of the Australian Integrated Multimodal EcoSystem (AIMES). AIMES is a world first; a grid mapped with smart sensors to test emerging, multimodal connected large-scale transport technologies in a complex urban environment. Through AIMES, Prof Sarvi is bringing the transport network together, collaborating with more than 50 domestic and international partners from industry and government. AIMES’ key objective is to deliver safer, more efficient and sustainable transport solutions for all road users to enable smarter cities to thrive. Prof Sarvi has more than 25 years of professional, academic and research experience in the areas of intelligent transport systems. His research is multidisciplinary with an international outlook applying theory to combat real-world challenges. His expertise covers a range of topics, including: Artificial Intelligence in Transport, connected and automated multimodal transport systems and CITS. He has been the author/co-author of over 350 refereed publications in top transportation journals and various conference and symposia proceedings. He currently serves on the editorial board of several journals including Transportation Research Part B, Transportation Research Part C, and Transportmetrica.

 

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