A multi-objective optimization model for identifying groups of critical elements in a high-speed train

This paper proposes a multi-objective optimization-based approach to identify critical elements, including units and interactions within and between systems, in a high-speed train (HST). In the framework, network theory is used to model the HST as an interdependent machine-electricity-communication network (IMECN) composed of a machine network (MN), an electricity network (EN) and a communication network (CN). Cascading failure models for the subnetworks and IMECN, and topological and functional metrics for robustness are developed. We then formulate a multi-objective optimization model for maximizing the impact of the failure of critical elements on the topological and functional robustness of the IMECN and minimizing their number. We use NSGA-II to solve the optimization problem. Considering a practical HST as a case study, we apply the multi-objective optimization framework to search the groups of critical nodes, intra-links and inter-links. The results show that critical nodes, intra-links and inter-links of the IMECN are within the MN and CN. In particular, end nodes of the critical intra-links and inter-links may also be critical, and the critical elements of subnetworks tend to also be critical for the IMECN. In addition, we find that the critical nodes, intra-links and inter-links are not related to their topological importance.

Automated summary

This paper proposes a multi-objective optimization-based approach to identify critical elements in a high-speed train system. The system is modeled as an interdependent machine-electricity-communication network, and cascading failure models and metrics for robustness are developed. By formulating a multi-objective optimization model, the impact of critical element failure on network robustness is maximized while minimizing their number. The results show that critical elements are mainly located within the machine and communication networks, and their importance is not related to their topological importance.