Multi-phased resilience methodology of urban sewage treatment network based on the phase and node recovery importance in IoT

As an important part of resilience city, the urban sewage system has an important impact on the normal operation of the city. However, the majority of recent study concentrates on a single phase, and multi-phased resilience has not been thoroughly studied. This paper analyzes the multi-phased resilience of the urban sewage treatment system considering the phase performance characteristics. Firstly, the definition of an urban sewage network is given, and the three phases of drainage, treatment, and recycling are analyzed. Secondly, descriptive resilience and mathematical resilience, Residual Resilience, Center of Resilience and Resilience Variance are given to model and assess resilience in accordance with the features of the three phases. What's more, residual resilience model is enhanced in accordance with the failure process and recovery process. Especially for the recovery process, the importance measures are used to set the node recovery importance and phase recovery importance to determine the recovery priority. Finally, a case study in two situations is given to illustrate the practicality and effectiveness of the proposed methods.