Vulnerability Analysis of Link-Weighted Shanghai Metrorail Transit Network

2018 ◽  
Author(s):  
Yanjie Zhang ◽  
Yalda Saadat ◽  
Dongming Zhang ◽  
Bilal M. Ayyub ◽  
Hongwei Huang
Keyword(s):  
Network Topology ◽  
Structural Features ◽  
Network Size ◽  
Global Network ◽  
Interval Length ◽  
Network Efficiency ◽  
Multiple Characteristic ◽  
Shanghai Metro ◽  
Metro System ◽  
Metro Network

With the degradation of metrorail facilities and the increase in network size, it is urgently needed to perform vulnerability assessment to ensure the safe operation of the metro system. In this paper, a link-weighted network model is proposed by considering the physical interval length between neighboring metro stations as link weight factor. Firstly, the metro network was essentially mapped into a bipartite topological diagram that consists of nodes denoting metro stations and links representing metro routes including any tunnels or bridges. After analyzing the network for its complexity level, it was revealed that the metro network topology can be appropriately constructed by using the Space L method. On this basis, multiple characteristic indexes of the network were calculated to characterize network topology structural features. We then tested the state of Shanghai metro network under different failure scenarios by removing a fraction of nodes from the network. Quantitative vulnerability analyses were conducted according to the change in the topological structure of Shanghai metro network and the change in the corresponding global network efficiency due to disruptions. Finally, both the network efficiency of link-weighted and unweighted Shanghai metro network topology were calculated and compared. This study has identified the vulnerable metro stations, which could provide support for the reasonable resource allocation of maintenance work and the decision-making in emergency treatment after failure. In order to increase the adaptability to emergencies and improve the operational efficiency, it was proposed that during the planning, construction, and operation of the metro system, the management and protection of the vulnerable stations should be given increased attention.

scholarly journals Route Redundancy-Based Network Topology Measure of Metro Networks

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Weiwei Jing ◽  
Xiangdong Xu ◽  
Yichao Pu
Keyword(s):  
Network Topology ◽  
Network Performance ◽  
Route Choice ◽  
Operating Conditions ◽  
Level Number ◽  
Metro Networks ◽  
Alternative Routes ◽  
Statistical Indicators ◽  
Metro System ◽  
Metro Network

The metro system plays a very important role in the urban multimodal transportation system, yet it is susceptible to accidents. A well-designed metro system needs to provide alternative routes to travellers both in the disruptive events and the normal operating conditions for providing rerouting opportunities and balancing crowded lines. This paper provides a new dimension of assessing metro network performance—travellers’ route redundancy (or route diversity), which is defined as the number of behaviourally effective routes between each origin-destination (O-D) pair in the network. The route redundancy of metro network is evaluated by statistical indicators of the distribution of the O-D-level number of effective routes. Compared with the existing connectivity and accessibility measures of topology network performance, route redundancy is also based on the topology network, but it takes the travellers’ route choice into consideration. Specifically, the effective routes between each O-D pair would provide disaggregated information from the travellers’ perspective. Case studies in four metropolises in the world, i.e., Shanghai, Beijing, London, and Tokyo, are conducted to examine the predisaster preparedness of the four metro networks explicitly from the perspective of route redundancy. The results indicate that the London metro network has the best route redundancy performance in terms of the statistical indicators of the distribution of the O-D level number of effective routes. Furthermore, the results of route redundancy are compared with typical measures of topology network performance in terms of measuring connectivity and accessibility of metro networks. Their differences are attributed to the fact that the route redundancy measure considers the travellers’ O-D-level route choice beyond the pure network topology and the shortest path considerations of the existing measures. The route redundancy proposed in this paper could assist in evaluating the predisaster preparedness of current or planning metro networks from O-D level to network level.

scholarly journals Social Networks and Loneliness During the COVID-19 Pandemic

2021 ◽  
Vol 7 ◽  
pp. 237802312098525
Author(s):  
Balazs Kovacs ◽  
Nicholas Caplan ◽  
Samuel Grob ◽  
Marissa King
Keyword(s):  
Social Network ◽  
Social Isolation ◽  
Close Relationships ◽  
Network Size ◽  
Global Network ◽  
Network Data ◽  
Network Characteristics ◽  
Face To Face ◽  
Social Network Data ◽  
Social Network Size

We utilize longitudinal social network data collected pre–COVID-19 in June 2019 and compare them with data collected in the midst of COVID in June 2020. We find significant decreases in network density and global network size following a period of profound social isolation. While there is an overall increase in loneliness during this era, certain social network characteristics of individuals are associated with smaller increases in loneliness. Specifically, we find that people with fewer than five “very close” relationships report increases in loneliness. We further find that face-to-face interactions, as well as the duration and frequency of interactions with very close ties, are associated with smaller increases in loneliness during the pandemic. We also report on factors that do not moderate the effect of social isolation on perceived loneliness, such as gender, age, or overall social network size.

scholarly journals Identification and Quantification of Node Criticality through EWM–TOPSIS: A Study of Hong Kong’s MTR System

2021 ◽  
Author(s):  
Yifan Zhang ◽  
S. Thomas Ng
Keyword(s):  
Hong Kong ◽  
Public Transportation ◽  
Early Stage ◽  
Network Robustness ◽  
Global Network ◽  
Practical Significance ◽  
Topsis Method ◽  
Urban Resilience ◽  
Network Efficiency ◽  
Entropy Weight

AbstractPublic transport networks (PTNs) are critical in populated and rapidly densifying cities such as Hong Kong, Beijing, Shanghai, Mumbai, and Tokyo. Public transportation plays an indispensable role in urban resilience with an integrated, complex, and dynamically changeable network structure. Consequently, identifying and quantifying node criticality in complex PTNs is of great practical significance to improve network robustness from damage. Despite the proposition of various node criticality criteria to address this problem, few succeeded in more comprehensive aspects. Therefore, this paper presents an efficient and thorough ranking method, that is, entropy weight method (EWM)–technology for order preference by similarity to an ideal solution (TOPSIS), named EWM–TOPSIS, to evaluate node criticality by taking into account various node features in complex networks. Then we demonstrate it on the Mass Transit Railway (MTR) in Hong Kong by removing and recovering the top k critical nodes in descending order to compare the effectiveness of degree centrality (DC), betweenness centrality (BC), closeness centrality (CC), and the proposed EWM–TOPSIS method. Four evaluation indicators, that is, the frequency of nodes with the same ranking (F), the global network efficiency (E), the size of the largest connected component (LCC), and the average path length (APL), are computed to compare the performance of the four methods and measure network robustness under different designed attack and recovery strategies. The results demonstrate that the EWM–TOPSIS method has more obvious advantages than the others, especially in the early stage.

scholarly journals Decreased Global Network Efficiency in Young Male Smoker: An EEG Study during the Resting State

2017 ◽  
Vol 8 ◽  
Author(s):  
Shaoping Su ◽  
Dahua Yu ◽  
Jiadong Cheng ◽  
Yajing Chen ◽  
Xiaohua Zhang ◽  
...  
Keyword(s):  
Resting State ◽  
Young Male ◽  
Global Network ◽  
Network Efficiency ◽  
Male Smoker

Data Highways

2012 ◽  
pp. 223-241
Author(s):  
Karina Mabell Gomez ◽  
Daniele Miorandi ◽  
David Lowe
Keyword(s):  
Network Topology ◽  
Ad Hoc ◽  
A Priori ◽  
Reaction Diffusion ◽  
Theoretical Work ◽  
Ad Hoc Wireless Networks ◽  
Global Network ◽  
Wireless Sensor ◽  
A Priori Knowledge ◽  
Reaction Diffusion Model

The design of efficient routing algorithms is an important issue in dense ad hoc wireless networks. Previous theoretical work has shown that benefits can be achieved through the creation of a set of data “highways” that carry packets across the network, from source(s) to sink(s). Current approaches to the design of these highways however require a–priori knowledge of the global network topology, with consequent communications burden and scalability issues, particularly with regard to reconfiguration after node failures. In this chapter, we describe a bio–inspired approach to generating these data highways through a distributed reaction–diffusion model that uses localized convolution with activation–inhibition filters. The result is the distributed emergence of data highways that can be tuned to provide appropriate highway separation and connection to data sinks. In this chapter, we present the underlying models, algorithms, and protocols for generating data highways in a dense wireless sensor network. The proposed methods are validated through extensive simulations performed using OMNeT++.

Shanghai Metro Flow: Multiple Perspectives into a Subway System

Leonardo ◽  
2017 ◽  
Vol 50 (5) ◽  
pp. 511-512
Author(s):  
Till Nagel ◽  
Benedikt Groß
Keyword(s):  
Urban Mobility ◽  
Multiple Perspectives ◽  
Aesthetic Form ◽  
Subway System ◽  
Shanghai Metro ◽  
The City ◽  
Metro Network

One of the main characteristics of cities is the large amount of people moving around. These flows are reflected in all the subways dashing through the city. With the authors’ work, they strive to give an impression of this pulse of the city. They present Shanghai Metro Flow, consisting of an animated visualization composed of three scenes, each giving another perspective into the metro network, and an accompanying poster showing subway line details. Each visualization combines established techniques with a highly aesthetic form in order to attract people to observe and dwell on different aspects of urban mobility.

Structural features and applications of metal–organic frameworks containing thiazole- and thiazolidine-based spacers

CrystEngComm ◽  
2015 ◽  
Vol 17 (2) ◽  
pp. 218-228 ◽  
Author(s):  
A. Rossin ◽  
G. Giambastiani
Keyword(s):  
Heterogeneous Catalysis ◽  
Crystal Structures ◽  
Network Topology ◽  
Metal Organic Frameworks ◽  
Structural Features ◽  
Metal Organic

This highlight describes the crystal structures and network topology of thiazole- and thiazolidine-containing MOFs and CPs along with their applications in the fields of CO2 adsorption, luminescence, magnetism and heterogeneous catalysis.

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