scholarly journals Robustness analysis in an inter-cities mobility network: modeling municipal, state and federal initiatives as failures and attacks toward SARS-CoV-2 containment

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10287
Author(s):  
Vander L.S. Freitas ◽  
Gladston J.P. Moreira ◽  
Leonardo B.L. Santos
Keyword(s):  
Robustness Analysis ◽  
Targeted Attacks ◽  
First Case ◽  
State Initiatives ◽  
Reactive Strategy ◽  
Federal Initiatives ◽  
City State ◽  
Robustness Metrics ◽  
Entire Network ◽  
Random Failures

We present a robustness analysis of an inter-cities mobility complex network, motivated by the challenge of the COVID-19 pandemic and the seek for proper containment strategies. Brazilian data from 2016 are used to build a network with more than five thousand cities (nodes) and twenty-seven states with the edges representing the weekly flow of people between cities via terrestrial transports. Nodes are systematically isolated (removed from the network) either at random (failures) or guided by specific strategies (targeted attacks), and the impacts are assessed with three metrics: the number of components, the size of the giant component, and the total remaining flow of people. We propose strategies to identify which regions should be isolated first and their impact on people mobility. The results are compared with the so-called reactive strategy, which consists of isolating regions ordered by the date the first case of COVID-19 appeared. We assume that the nodes’ failures abstract individual municipal and state initiatives that are independent and possess a certain level of unpredictability. Differently, the targeted attacks are related to centralized strategies led by the federal government in agreement with municipalities and states. Removing a node means completely restricting the mobility of people between the referred city/state and the rest of the network. Results reveal that random failures do not cause a high impact on mobility restraint, but the coordinated isolation of specific cities with targeted attacks is crucial to detach entire network areas and thus prevent spreading. Moreover, the targeted attacks perform better than the reactive strategy for the three analyzed robustness metrics.

scholarly journals Interdependency and Vulnerability of Multipartite Networks under Target Node Attacks

Complexity ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-16
Author(s):  
Qing Cai ◽  
Mahardhika Pratama ◽  
Sameer Alam
Keyword(s):  
Complex Networks ◽  
Robustness Analysis ◽  
Network Models ◽  
Continuous Phase ◽  
Structure Design ◽  
Network Robustness ◽  
Multilayer Networks ◽  
Component Theory ◽  
Centrality Metrics ◽  
Entire Network

Complex networks in reality may suffer from target attacks which can trigger the breakdown of the entire network. It is therefore pivotal to evaluate the extent to which a network could withstand perturbations. The research on network robustness has proven as a potent instrument towards that purpose. The last two decades have witnessed the enthusiasm on the studies of network robustness. However, existing studies on network robustness mainly focus on multilayer networks while little attention is paid to multipartite networks which are an indispensable part of complex networks. In this study, we investigate the robustness of multipartite networks under intentional node attacks. We develop two network models based on the largest connected component theory to depict the cascading failures on multipartite networks under target attacks. We then investigate the robustness of computer-generated multipartite networks with respect to eight node centrality metrics. We discover that the robustness of multipartite networks could display either discontinuous or continuous phase transitions. Interestingly, we discover that larger number of partite sets of a multipartite network could increase its robustness which is opposite to the phenomenon observed on multilayer networks. Our findings shed new lights on the robust structure design of complex systems. We finally present useful discussions on the applications of existing percolation theories that are well studied for network robustness analysis to multipartite networks. We show that existing percolation theories are not amenable to multipartite networks. Percolation on multipartite networks still deserves in-depth efforts.

scholarly journals OPTIMIZATION OF ROBUSTNESS OF SCALE-FREE NETWORK TO RANDOM AND TARGETED ATTACKS

2005 ◽  
Vol 19 (16) ◽  
pp. 785-792 ◽  
Author(s):  
JIAN-GUO LIU ◽  
ZHONG-TUO WANG ◽  
YAN-ZHONG DANG
Keyword(s):  
Network Design ◽  
Scale Free Network ◽  
Design Guideline ◽  
Scale Free ◽  
Targeted Attacks ◽  
Maximum Value ◽  
Scale Free Networks ◽  
Free Network ◽  
Random Failures ◽  
Connectivity Distribution

Scale-free networks, having connectivity distribution P(k)~k-α (where k is the site connectivity), are very resilient to random failures but are fragile to intentional attacks. The purpose of this paper is to find the network design guideline which can make the robustness of the network to both random failures and intentional attacks maximum while keeping the average connectivity <k> per node constant. We find that when <k> = 3 the robustness of the scale-free networks reach its maximum value if the minimal connectivity m = 1, but when <k> is larger than four, the networks will become more robust to random failures and targeted attacks as the minimal connectivity m gets larger.

scholarly journals Studying the Topology of Transportation Systems through Complex Networks: Handle with Care

2018 ◽  
Vol 2018 ◽  
pp. 1-17 ◽  
Author(s):  
Massimiliano Zanin ◽  
Xiaoqian Sun ◽  
Sebastian Wandelt
Keyword(s):  
Complex Network ◽  
Real World ◽  
Paradigm Shift ◽  
Transportation Networks ◽  
Transportation Systems ◽  
Node Ranking ◽  
Targeted Attacks ◽  
Topological Characteristics ◽  
Definition Of ◽  
Random Failures

The introduction of complex network concepts in the study of transportation systems has supposed a paradigm shift and has allowed understanding different transport phenomena as the emergent result of the interactions between the elements composing them. In spite of several notable achievements, lurking pitfalls are undermining our understanding of the topological characteristics of transportation systems. In this study, we analyse four of the most common ones, specifically related to the assessment of the scale-freeness of networks, the interpretation and comparison of topological metrics, the definition of a node ranking, and the analysis of the resilience against random failures and targeted attacks. For each topic we present the problem from both a theoretical and operational perspective, for then reviewing how it has been tackled in the literature and finally proposing a set of solutions. We further use six real-world transportation networks as case studies and discuss the implications of these four pitfalls in their analysis. We present some future lines of work that are stemming from these pitfalls and that will allow a deeper understanding of transportation systems from a complex network perspective.

Transnational Higher Education Strategies into and out of Singapore: Commodification and Consecration

2015 ◽  
Vol 4 (1) ◽  
pp. 85-108 ◽  
Author(s):  
Rebecca Ye
Keyword(s):  
Higher Education ◽  
Turn Of The Century ◽  
Asian Students ◽  
Educational Mobility ◽  
Mass Higher Education ◽  
Transnational Higher Education ◽  
Studying Abroad ◽  
First Case ◽  
City State ◽  
The Uk

AbstractThis article addresses transnational higher education strategies both to and from Singapore. It does so by focusing on outbound educational mobility from Singapore to the UK and inbound educational mobility from Vietnam to Singapore. Since the turn of the century, Singapore has pursued the agenda of developing itself as a regional hub for higher education, aspiring to be a Global Schoolhouse. Yet, while the number of international students grows in local universities, Singapore's academically brightest do not necessarily take advantage of higher educational opportunities within the shores of the city-state, with many traveling to universities overseas through a form of sponsored mobility. Using two case studies, I trace two logics of commodification and consecration as observed through the processes whereby individuals and institutions devise transnational higher education strategies into and out of Singapore. The first case study draws on interviews conducted with Singaporean undergraduates at Oxbridge while the second case focuses on Vietnamese students at two Singaporean universities. Together, the analysis from these cases uncovers the value for these Southeast Asian students in studying abroad and distinguishes between different types of routes that exist: one where students choose their own educational plans and another where students are chosen for a prestigious educational and occupational pathway. With increasing participation in mass higher education taking place across the region, the article outlines, through the site of Singapore, strategies of transnationalism employed by both individuals and institutions as a means of social differentiation.

scholarly journals Percolation Theories for Multipartite Networked Systems under Random Failures

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Qing Cai ◽  
Sameer Alam ◽  
Mahardhika Pratama ◽  
Zhen Wang
Keyword(s):  
Complex Systems ◽  
Robustness Analysis ◽  
Network Models ◽  
Networked Systems ◽  
Network Robustness ◽  
Cascading Failures ◽  
Connected Component ◽  
System Components ◽  
Random Node ◽  
Random Failures

Real-world complex systems inevitably suffer from perturbations. When some system components break down and trigger cascading failures on a system, the system will be out of control. In order to assess the tolerance of complex systems to perturbations, an effective way is to model a system as a network composed of nodes and edges and then carry out network robustness analysis. Percolation theories have proven as one of the most effective ways for assessing the robustness of complex systems. However, existing percolation theories are mainly for multilayer or interdependent networked systems, while little attention is paid to complex systems that are modeled as multipartite networks. This paper fills this void by establishing the percolation theories for multipartite networked systems under random failures. To achieve this goal, this paper first establishes two network models to describe how cascading failures propagate on multipartite networks subject to random node failures. Afterward, this paper adopts the largest connected component concept to quantify the networks’ robustness. Finally, this paper develops the corresponding percolation theories based on the developed network models. Simulations on computer-generated multipartite networks demonstrate that the proposed percolation theories coincide quite well with the simulations.

METABOLIC NETWORKS ROBUSTNESS: THEORY, SIMULATIONS AND RESULTS

2011 ◽  
Vol 12 (03) ◽  
pp. 221-240 ◽  
Author(s):  
SALVATORE VITABILE ◽  
VINCENZO CONTI ◽  
BARBARA LANZA ◽  
DOMENICO CUSUMANO ◽  
FLIPPO SORBELLO
Keyword(s):  
Metabolic Pathways ◽  
Metabolic Networks ◽  
Functional Module ◽  
Robustness Analysis ◽  
Integrated Approach ◽  
Normal Operation ◽  
Functional Modules ◽  
Network Behavior ◽  
Operation Conditions ◽  
Targeted Attacks

Metabolic networks are composed of several functional modules, reproducing metabolic pathways and describing the entire cellular metabolism of an organism. In the last decade, an enormous interest has grown for the study of tolerance to errors and attacks in metabolic networks. Studies on their robustness have suggested that metabolic networks are tolerant to errors, but very vulnerable to targeted attacks against highly connected nodes. However, many findings on metabolic networks suggest that the above classification is too simple and imprecise, since hub node attacks can be by-passed if alternative metabolic paths can be exploited. On the contrary, non-hub nodes attacks can affect cell survival when the node is the only path within a functional module. In this paper an integrated approach for metabolic networks robustness analysis is presented. With more details, statistical, topological, and functional analysis are used together to evaluate metabolic network behavior under normal operation conditions and under random or targeted attacks. Two real biological metabolic networks have been used to test the effectiveness of the proposed approach.

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