A Water Distribution System (WDS) is a critical infrastructure for society and economy, subject to frequent maintenance either for contingencies or planned operations. Maintenance procedures affect the hybrid dynamics of a WDS at stochastic time points, representing the completion of repair activities that change the WDS topology and operation mode. Hence, the problem of performability evaluation of the WDS behavior during a maintenance intervention falls in the class of stochastic hybrid systems (SHSs), for which existing numerical or simulative approaches cannot afford the complexity of realistic WDSs. We propose a viable approach that computes the expected demand not served during a maintenance procedure by integrating fluid-dynamic analysis of the WDS with quantitative evaluation of the procedure timing, notably assuming non-Markovian repair times over a bounded support. Different solution techniques are presented to evaluate the joint distribution of the times when the procedure affects the WDS, performing either simulation of the procedure model or state-space analysis based on an extension of the method of stochastic state classes. Feasibility and effectiveness of the proposed methods are assessed on a real WDS in terms of result accuracy and computational complexity, showing that the overall approach could be efficiently applied in higher level tasks including activity scheduling, resource planning, and budget allocation.

中文翻译：

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维护过程中配水系统的性能评估

配水系统 (WDS) 是社会和经济的关键基础设施，需要经常维护以应对突发事件或计划运营。维护程序在随机时间点影响 WDS 的混合动力学，代表改变 WDS 拓扑和操作模式的修复活动的完成。因此，维护干预期间 WDS 行为的可执行性评估问题属于随机混合系统 (SHS)，现有的数值或模拟方法无法承受现实 WDS 的复杂性。我们提出了一种可行的方法，通过将 WDS 的流体动力学分析与过程时间的定量评估相结合，计算维护过程中未满足的预期需求，特别是假设在有界支持上的非马尔可夫修复时间。提出了不同的求解技术来评估程序影响 WDS 的时间的联合分布，执行程序模型的模拟或基于随机状态类方法的扩展的状态空间分析。在结果准确性和计算复杂性方面，在真实 WDS 上评估了所提出方法的可行性和有效性，表明整体方法可以有效地应用于更高级别的任务，包括活动调度、资源规划和预算分配。基于随机状态类方法的扩展执行过程模型的模拟或状态空间分析。在结果准确性和计算复杂性方面，在真实 WDS 上评估了所提出方法的可行性和有效性，表明整体方法可以有效地应用于更高级别的任务，包括活动调度、资源规划和预算分配。基于随机状态类方法的扩展执行过程模型的模拟或状态空间分析。在结果准确性和计算复杂性方面，在真实 WDS 上评估了所提出方法的可行性和有效性，表明整体方法可以有效地应用于更高级别的任务，包括活动调度、资源规划和预算分配。