Cascading Failure Analysis on Shanghai Metro Networks: An Improved Coupled Map Lattices Model Based on Graph Attention Networks

Analysis of the robustness and vulnerability of metro networks has great implications for public transport planning and emergency management, particularly considering passengers’ dynamic behaviors. This paper presents an improved coupled map lattices (CMLs) model based on graph attention networks (GAT) to study the cascading failure process of metro networks. The proposed model is applied to the Shanghai metro network using the automated fare collection (AFC) data, and the passengers’ dynamic behaviors are simulated by GAT. The quantitative cascading failure analysis shows that Shanghai metro network is robust to random attacks, but fragile to intentional attacks. Moreover, there is an approximately normal distribution between instant cascading failure speed and time step and the perturbation in a station which leads to steady state is approximately a constant. The result shows that a station surrounded by other densely distributed stations can trigger cascading failure faster and the cascading failure triggered by low-level accidents will spread in a short time and disappear quickly. This study provides an effective reference for dynamic safety evaluation and emergency management in metro networks.

MLCOR Model for Suppressing the Cascade of Edge Failures in Complex Network

As a decisive parameter of network robustness and network economy, the capacity of network edges can directly affect the operation stability and the construction cost of the network. This paper proposes a multilevel load–capacity optimal relationship (MLCOR) model that can substantially improve the network economy on the premise of network safety. The model is verified in artificially created networks including free-scale networks, small-world networks, and in the real network structure of the Shanghai Metro network as well. By numerical simulation, it is revealed that under the premise of ensuring the stability of the network from the destruction caused by initial internal or external damage on edge, the MLCOR model can effectively reduce the cost of the entire network compared to the other two linear load–capacity models regardless of what extent of the destruction that the network edges suffer initially. It is also proved that there exists an optimal tunable parameter and the corresponding optimal network cost for any BA and NW network topology, which can provide the reference for setting reasonable capacities for network edges in a real network at the stage of network planning and construction, promoting security and stability of network operation.

Shanghai Metro Constructs an “Intelligent Metro”

The World Artificial Intelligence (AI) Conference 2020 opened in Shanghai on July 9, 2020. The AI application scenarios presented by Shanghai Shentong Metro Group Co., Ltd. (Shentong Metro Group) have attracted a lot of attention of visitors. On July 9, 2020, the total passenger flow of Shanghai Metro exceeded 10 million, reaching 10.048 million, and Shanghai will enter the normal state of “ten million passenger flow” every day. At present, the operating mileage of Shanghai Metro reaches 705km, ranking first in the world. According to the new line planning and construction trend, the Shanghai Metro network will continue to expand, and there will be even more passenger flows in the future.

A Location-Based Device Tree System for Rail Transit

As the Vehicle Branch of Shanghai Metro Maintenance Guarantee Co., Ltd. is making continued progress in refined management, it requires increasing fine data granularity, together with increasing needs for data analysis. Therefore, the existing serial-number-based device trees can no longer meet continuous increasing management requirements, which necessitates a new device tree system. This paper has proposed a new device tree system for rail transit. Based on the physical locations of rail transit devices, the system proposed can associate the location information with property information, equipment serial number, and fault trees. Hence a subway vehicle and fault management system based on device trees was established. Based on the actual situation and management requirements of the Vehicle Branch, this paper has developed a location-based device tree management system and coding scheme, and introduced its advantages in management.