Modeling Interdependent Infastructures and Optimizing Investments

我们国家的安全和公民的生活质量取决于一系列复杂的、相互依存的基础设施的持续可靠运行，这些基础设施包括交通、电力、石油、天然气、电信和应急服务。一个基础设施的中断会迅速而显著地影响到另一个基础设施，在全国范围内引起涟漪。我们的基础设施越来越依赖新的信息技术和互联网来运作，它们往往通过电子信息链路相互连接。虽然这些技术可以极大地提高效率，但它们也产生了新的漏洞。我们只需点击一下鼠标就能在全球范围内传输信息的技术，也可以被用来破坏我们的重要系统，包括电力或水的流动，以及紧急服务的调度。我们的许多基础设施都是私人拥有的，这些公司面临着短期财务业绩的巨大压力。这种压力可能导致未来投资不足。基础设施之间日益增加的相互依赖性和日益增加的经济压力的融合，意味着迫切需要了解这些系统是如何相互依赖的，以便基础设施系统，或“大型基础设施”，在保持其财务可行性的同时，不太容易受到破坏。该项目侧重于开发可计算的数学模型，以评估相互依赖的基础设施的性能并优化投资。我们采用的数学方法的一个关键方面是创建一个统一的数学框架来表示这些大型基础设施和一组可用于估计性能和优化投资的算法。这个统一的数学框架需要有足够的细节，以提供对物理设施和网络技术对性能的影响的理解，但在实际应用中仍然可以计算处理。它还必须明确关注这些系统中潜在的不确定性。这项工作的主要焦点是马尔可夫和半马尔可夫模型在这方面的适用性。

Our nation's security as well as the quality of life of its citizenry depends on the continuous reliable operation of a collection of complicated interdependent infrastructures including transportation, electric power, oil, gas, telecommunications and emergency services. A disruption in one infrastructure can quickly and significantly impact another, causing ripples across the nation. Our infrastructures are increasingly reliant on new information technologies and the Internet to operate, often being connected to one another via electronic, informational links. While these technologies allow for enormous gains in efficiency, they also create new vulnerabilities. The same technology that allows us to transmit information around the globe at the click of a mouse can be used to disrupt our vital systems including the flow of electric power or water, and the dispatch of emergency services. Many of our infrastructures are privately-owned by companies that face strong pressure for short-term financial results. This pressure may lead to under-investment for the future. The confluence of increasing interdependency among infrastructures and increasing economic pressures implies a significant need to understand how these systems are interdependent so that systems of infrastructures, or "mega infrastructures," are less vulnerable to disruption while maintaining their financial viability. This project focuses on the development of computationally tractable mathematical models to asse the performance of interdependent infrastructure and to optimize investment. A key aspect of the mathematical approach we are taking is the creation of a unifying mathematical framework to represent these mega infrastructures and a collection of algorithms that can be used to estimate performance and optimize investment. This unifying mathematical framework needs to be of sufficient detail to provide an understanding of the impact of the physical facilities and cyber technologies on performance, but remain computationally tractable for realistic application. It must also play explicit attention to the underlying uncertainty in these systems. A primary focus of this effort is the applicability of Markov and semi-Markov models for this purpose.