Collaborative Research: RIPS Type 2: Vulnerability Assessment and Resilient Design of Interdependent Infrastructures

现代基础设施系统(如电网、通信网络和交通网络)相互依赖，以至于一个系统中的一个元件发生故障可能会导致其他系统中的多个元件发生故障。这一过程可能会以级联方式在相互依赖的系统之间来回传播，导致灾难性的大范围故障。此外，人类对各种行为的干扰，如司机？对堵塞的反应，可能会使级联行为进一步复杂化。评估和设计相互依赖的弹性系统需要全新的模型和分析技术。在这个项目中，来自计算机科学、优化、交通系统、电力工程和社会科学领域的五名研究人员将共同努力，以更好地了解连锁故障现象，开发用于设计弹性相互依赖系统的易于处理的数学模型，并研究通过防止连锁故障的发生和快速恢复系统运行来增强相互依赖系统的弹性的创新策略。这项研究将为理解相互依赖的系统在干扰下的稳健性的基本性质奠定基础，从而促进现代复杂网络理论和优化算法的发展。该项目的变革性贡献如下。研究人员将提供第一个能够表征相互依赖系统中连锁故障的规模和深度的模型，引入人的脆弱性的新概念，并提供第一个基于可服务性的识别关键网元的模型。研究结果将为公共和私营机构提供及时的支持，以便更好地了解连锁故障的影响和保护关键要素的影响，并制定政策，以增强相互依存的基础设施系统的弹性。特别是，这些发现可能会使这些政策在管理交通网络和电网方面的选择多样化。研究成果还将丰富网络科学、图论、优化、通信、交通系统、电力工程和社会科学领域的文献。该项目将涉及各级学生，重点是吸引代表人数不足的群体的学生。真实世界的应用程序将提供一个理想的平台来吸引本科生和K-12学生，并接触到实践者和政策制定者。通过理论(数学建模和优化)和应用(领域专业知识)方法的结合，该项目将全面调查相互依赖的系统中的脆弱性和弹性问题。作为实现这一目标的具体步骤，研究人员将进行五个跨学科的研究任务：1)通过数学量化级联的“深度”和“广度”来分析相互依赖系统中的连锁故障的机制；2)确定关键元件(节点和/或链路)，其移除将导致相互依赖系统的弹性损失最显著；3)通过优化增加网络间链路来增强相互依赖系统的弹性，并在系统衰退为全面故障之前找到快速对连锁行为作出反应的自适应控制策略；4)研究与关键要素相关的“人的脆弱性”，推导出人的脆弱性的度量，并将其进一步集成到相互依赖系统的数学模型中，以完善关键要素的检测；5)将所提出的严格的数学模型和算法应用于佛罗里达州由电网、通信网络和交通网络组成的真实世界中影响人类行为的相互依赖的网络。

Modern infrastructure systems, such as power grids, communication networks, and transportation networks are interdependent in such a way that a failure of an element in one system may cause multiple failures of elements in other systems. This process can propagate back and forth between interdependent systems in a cascading fashion, resulting in a catastrophic widespread failure. In addition, the diverse human behaviors to disruptions, such as drivers? reaction to gridlock, can further complicate the cascading behaviors. Radically new models and analytical techniques are needed to assess and design resilient interdependent systems.In this project, a team of five investigators from the domains of computer science, optimization, transportation systems, power engineering, and social science will work together to gain a better understanding of cascading failure phenomena, develop tractable mathematical models for designing resilient interdependent systems, and investigate innovative strategies to enhance the resilience of interdependent systems by preventing the occurrence of cascading failures and quickly restoring system operations. This research will lay a foundation in understanding the fundamental properties that contribute to the robustness of interdependent systems under disruptions, and thus, advancing the state-of-the-art in modern complex network theory and optimization algorithms. The transformative contributions of the project are as follows. The investigators will offer the first models that can characterize the scale and depth of cascading failures in interdependent systems, introduce the new concept of ?human vulnerability?, and provide the first model on identifying critical network elements based on serviceability. The findings of the research will provide timely support for public and private agencies to better understand the impacts of cascading failures and the implications of protecting critical elements, and develop policies to enhance the resilience of the interdependent infrastructure systems. In particular, the findings can potentially diversify the choices of these policies for managing transportation networks and power grids. The research results will also enrich the literature in the areas of network science, graph theory, optimization, communications, transportation systems, power engineering, and social science. The project will involve students at all levels, with emphasis on attracting students from underrepresented groups. The real-world applications will offer an ideal platform to engage undergraduate and K-12 students and to reach out to practitioners and policy makers.Via a combination of theoretical (mathematical modeling and optimization) and applied (domain expertise) approaches, this project will comprehensively investigate vulnerability and resilience issues in interdependent systems. As specific steps towards this goal, the investigators will pursue five interdisciplinary research tasks: 1) analyzing the mechanisms of cascading failures in interdependent systems by mathematically quantifying the "depth" and "breadth" of cascades; 2) identifying critical elements (nodes and/or links) whose removal yields the most significant loss of resilience of interdependent systems; 3) enhancing the resilience of interdependent systems via optimal addition of inter-network links and finding adaptive control strategies to rapidly react to the cascading behaviors before the systems decay into full-blown failure; 4) investigating "human vulnerability" associated with critical elements, and deriving metrics of human vulnerability, which will be further integrated into the mathematical models of interdependent systems to refine the detection of critical elements; 5) applying the proposed rigorous mathematical models and algorithms to the real-world interdependent networks in Florida, which consist of power grids, communication networks, and transportation networks, with an impact of human behavior.