主讲人:曲小波(Dr Xiaobo Qu)
报告主题：On the fundamental diagram for freeway traffic
Abstract: The speed-density or flow-density relationship has been considered as the foundation of traffic flow theory. Existing single-regime models calibrated by the least square method (LSM) could not fit the empirical data consistently well both in light-traffic/free-flow conditions and congested/jam conditions. In this paper, first, we point out that the inaccuracy of single-regime models is not caused solely by their functional forms, but also by the sample selection bias. Second, we apply a weighted least square method (WLSM) that addresses the sample selection bias problem. The calibration results for six well-known single-regime models using the WLSM fit the empirical data reasonably well both in light-traffic/free-flow conditions and congested/jam conditions. Third, we conduct a theoretical investigation that reveals the deficiency associated with the LSM is because the expected value of speed (or a function of it) is nonlinear with regard to the density (or a function of it).
主讲人简介：曲小波(Dr Xiaobo Qu)：现为悉尼科技大学土木与环境工程系交通工程Senior Lecturer，也曾在格里菲斯大学任教。本科毕业于吉林大学，获清华大学硕士学位，新加坡国立大学博士学位。其研究重点是通过交通流和网络建模和优化来提高交通安全、效率、公平性和可持续性。他的教学表现在格里菲斯大学和悉尼科技大学都备受好评，多次获评优秀教师。他撰写或与他人合作撰写在Transportation Research Part A, Part B, Part C, Part E等期刊上发表了50多篇优秀论文。曾在2009年获得交通部（新加坡）创新奖，2015年EPPM最佳论文奖等奖项。
Dr Xiaobo Qu is currently a Senior Lecturer (Transport Engineering) with the School of Civil and Environmental Engineering, University of Technology Sydney (UTS), Sydney Australia. Prior to his UTS appointment, he was a Senior Lecturer (Transport Engineering) in Griffith School of Engineering, Griffith University, Queensland, Australia. Dr Qu obtained his PhD, Master's degree, Bachelor's degree from the National University of Singapore, Tsinghua University, and Jilin University, respectively.
Dr Qu's research is focused on practically improving transport safety, efficiency, equity, and sustainability through traffic flow and network modelling and optimisation. He has authored or co-authored over 50 journal articles published by leading international peer reviewed transportation journals such as Transportation Research Part A, Part B, Part C, Part E, Accident Analysis and Prevention, ASCE - Journal of Transportation Engineering, and Risk Analysis. He is a recipient of Ministry of Transport (Singapore) Minister's Innovation Award in 2009, President's Graduate Fellowship (Singapore) in 2010-2011, ASCE - Journal of Transportation Engineering Outstanding Reviewer Award in 2013, Griffith University Pro-Vice Chancellor Early Career Research Excellence Award in 2015, Griffith University Pro-Vice Chancellor Research Excellence Award (Group Category) in 2015, EPPM 2015 best paper award, and Australian Government Endeavour Cheung Kong Fellowship in 2016.
Dr Qu also has a great passion for teaching and scholarship. His teaching performance has always been among the best in not only Griffith University but also University of Technology Sydney. His teaching has been distinguished by the Griffith University Dean's letter of outstanding in teaching in 2012 and 2013, Griffith University Dean's Learning and Teaching Commendation in 2014, Griffith University Dean's Learning and Teaching Citation in 2015, nominee of lecturer of the year (finalist) in 2015, and three peer reviewed articles in Learning & Teaching scholarship. Dr Qu has supervised two PhD students towards completion as their primary supervisor who both secured professional placement (one as a Lecturer in another Australian University, and the other as a traffic consultant in a consulting firm) before thesis submission, and he is currently supervising four PhD students as their primary/sole supervisor.