Criticality of Urban Networks: Untangling the Complexity of Urban Congestion

该奖项将支持探索复杂科学工具和方法的应用，以更好地理解和控制城市拥堵的研究。这种范式转换的方法是根据最近的经验数据制定的，这些数据证实了早期的理论，即通过城市交通网络的交通流量就像容器内的流体。在这个类比中，高峰时段的拥堵可以被认为是流体的沸点，在这里人们可以观察到两种不同的物质状态以不同的比例共存，这取决于温度：气体（很少拥堵）和液体（停止，堵在路上）。这就是交通流变得混乱的地方，因此我们传统的工程工具，如微积分和统计学，不再适用于预测和控制。本研究为在此背景下描述和建模交通流系统提供了一个框架。这个计划的教育部分将促进和促进基础复杂系统教育纳入佐治亚理工学院土木工程课程。相变理论是物理学中较容易理解的理论之一，但由于缺乏对系统中热流的适当描述，到目前为止还没有成功地应用于交通流。本项目提出车辆流动作为一种正确的解释，研究方法包括分析大量的经验观察，结合数学建模和理论分析，在复杂性科学的总体框架内结合交通流理论、统计力学和分形几何的元素。与本项目最相关的将是自组织临界性（SOC）理论及其与不同普适性类的联系，如Manna， karda - paris - zhang和定向渗透类，所有这些最近在交通网络的背景下都受到了很多关注。SOC已被发现在从地质学到天体物理学的各个领域都是基础，该项目将探索城市网络是否属于这一类，以及控制城市拥堵的方法含义。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This award will support research to explore the application of tools and methods from complexity science to better understand and control urban congestion. This paradigm-shifting approach is made in light of recent empirical data confirming earlier theories that the flow of traffic through urban transportation networks behaves like a fluid inside a container. In this analogy, rush-hour congestion can be thought of as the boiling point of the fluid, where one can observe two distinct states of matter coexisting in different proportions depending on the temperature: gas (little congestion) and liquid (stopped, stuck in traffic). This is where traffic flow becomes chaotic and therefore our traditional engineering tools such as calculus and statistics no longer apply to prediction and control. This research provides a framework for describing and modeling traffic flow systems in this context. The educational component of this project will promote and facilitate the incorporation of basic complex systems education into the civil engineering curricula at Georgia Tech.The theory of phase transitions is one of the better understood theories in physics, but it has not been applied to traffic flow successfully so far due to the lack of a suitable description of heat flow in the system. This project suggests the flow of vehicles as a correct interpretation, and the research approach includes the analysis of large amounts of empirical observations, together with mathematical modeling and theoretical analysis that will combine elements from traffic flow theory, statistical mechanics and fractal geometry within the overall framework of complexity science. Most relevant to this project will be the theory of self-organized criticality (SOC) and its connections with different universality classes such as Manna, Kardar-Parisi-Zhang and directed percolation classes, all of which have received much attention lately in the context of traffic networks. SOC has been found to be fundamental in diverse areas from geology to astrophysics, and this project will explore if urban networks fall in this category, along with the methodological implications for controlling urban congestion.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.