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中科大复杂系统研究组学术报告会通知

时间:2014-06-20 17:25:36  来源:  作者:

 时间:2014年6月20日(星期五)下午4:00-6:00

 

 

地点:中科大东区理化大楼17-009教室

 

报告人及报告题目:

 

4:00-4:40 张鹏教授(上海大学应用数学及力学研究所)

报告题目:Multi-Grid Potential Field Cellular Automata Model for Pedestrian Flow

Abstract:Differing from the flow in classical fluid dynamics which is governed by natural (Newtonian) forces, pedestrians are self driven according to their destination and surroundings. Thus, the rule of path choice is a key issue for the formulation of pedestrian flow. Assuming that pedestrians are sufficiently smart and familiar with the walking facility and surroundings, the optimal principle that is similar to the optical propagation is adopted for the path choice. Here, the optimal path is solved from the Eikonal equation numerically.

 

In general, we show that how the principle is applied in the macroscopic partial differential equation model and the microscopic Cellular Automaton (CA) model. In the former case, the well-known LWR model and other higher-order models of traffic flow can be extended through combination with the Eiknoal equation. In the latter case, a potential field (PF) is proposed to replace the classical floor field, which (being called PFCA model) suggests a flexible handling of a walking domain with complex geometries and efficiency for computation.

 

In particular, a recently proposed multi-grid PFCA model is discussed, which is a significant extension of the PFCA model. By assuming that a pedestrian normally occupies nine refined cells but somehow can share a refined cell with a other pedestrians, the model is able to describe overcrowded pedestrian flow with a maximal density up to 14.06 ped./m2. Moreover, typical phenomena such as the arching in a bottleneck and the lane formation in counter flow are significantly improved.

 

张鹏简介 ABOUT THE SPEAKER

Professor Peng Zhang has a bachelor's degree in Mathematics from Sichuan University, a PhD and DSc in Mathematics from the University of Science and Technology of China. He is now a full professor at Shanghai Institute of Applied Mathematics and Mechanics, Shanghai University, China. Professor Zhang has an educational and research background in the computational theory of hyperbolic conservation laws, and he focuses on traffic flow problems using the theory. His contribution to traffic flow problems mainly involves the mathematical theory, which includes the analytical properties in (1) the higher-order model; (2) the multi-class model; and (3) the models with discontinuous fluxes or inhomogeneous road conditions. Since 2003, he has published more than 30 SCI papers on such reputed Journals as J. Comput. Phys., Euro. J. Appl. Math., Numer. Meth. Partial Diff. Equ., SIAM J. Appl. Math., Appl. Numer. Math., J Comput. Appl. Math., Phys. Rev. E, Trans. Res. Part B, etc.

 

4:40-5:00 李明 (中国科学技术大学近代物理系博士后)

报告题目:连接边与相依边的重叠对网络渗流的影响

Abstract:考虑到实际网络中元素的特点,近期对网络结构与级联故障的研究中,节点间的相依性已以相依边的形式被引入网络模型中。由于相依边的断裂会使得多个相依节点同时损坏,所以这种边的引入使得网络更加脆弱。但令人惊奇的是,不同于经典网络渗流的连续相变,当相依边数量较多时,系统展现出不连续相变。为了更为贴近真实情况,我们抛开了相依边与连接边的独立性假设,考虑了两种边的重叠效应。通过理论分析与数值模拟,我们发现节点之间的相依并不总是使得相变不连续。当重叠率由低到高变化时,网络的渗流过程从一阶相变转化成二阶相变。这说明相依边数量并不是系统相变类型的唯一决定因素,相依节点之间的连接性也是一个重要因素。

 

5:00-5:20 邓化宇 (上海大学应用数学及力学研究所)

报告题目:基于supply-demand对流和“碰撞”耦合效应的网络交通流

 

5:20-5:40 林志阳(上海大学应用数学及力学研究所)

报告题目:LWR模型和高阶守恒模型数值格式:推广到网络交通流计算

 

5:40-6:00 李启朗教授 (安徽建工大学)

报告题目:十字路口瓶颈处混合交通流的相图

 

 

 

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