Node-based Attack Research Articles

A Critical Candidate Node-Based Attack Model of Network Controllability.

The controllability of complex networks is a core issue in network research. Assessing the controllability robustness of networks under destructive attacks holds significant practical importance. This paper studies the controllability of networks from the perspective of malicious attacks. A novel attack model is proposed to evaluate and challenge network controllability. This method disrupts network controllability with high precision by identifying and targeting critical candidate nodes. The model is compared with traditional attack methods, including degree-based, betweenness-based, closeness-based, pagerank-based, and hierarchical attacks. Results show that the model outperforms these methods in both disruption effectiveness and computational efficiency. Extensive experiments on both synthetic and real-world networks validate the superior performance of this approach. This study provides valuable insights for identifying key nodes crucial for maintaining network controllability. It also offers a solid framework for enhancing network resilience against malicious attacks.

Enhancing the robustness of influential seeds towards structural failures on competitive networks via a Memetic algorithm

Networked systems present the correlative relation between entities, and the related knowledge excavation problem has been greatly emphasized in the last decade. The determination of influential nodes is modeled as the influence maximization problem, and the robustness issue has also been studied. Meanwhile, a specific network may maintain multiple diffusive groups, and the robustness of seeds under this environment is important to solve propagation tasks. Rational diffusion models have been developed in related studies, and valid algorithms are devised to find effective seeds. However, existing studies only consider the node-based attacks, and omit the impact of link removals on the robustness of seeds under competitive environments. As an indispensable component of networks, links show significance in sustaining the functionality, the analysis on link-based attacks is thus necessary. Aiming at addressing this deficiency, an importance metric is designed to evaluate the centrality of links in the diffusion process on competitive networks. Equipped with this metric, a numerical measure is developed to evaluate the performance of a given seed set. Further, the structural information and genetic information is considered to guide the search process. Several problem-directed operators are given to combine valuable knowledge from both myopic and holistic solution spaces. A Memetic algorithm is constructed to tackle the robust influence maximization problem on competitive networks under link-based attacks, termed MA-RCIM-L. The algorithm is tested on both synthetic and real-world networks, whose competitiveness against existing approaches is demonstrated.

Finding robust influential seeds from networked systems against structural failures using a niching memetic algorithm

There has been a growing interest in analyzing the dynamics and characteristics of networked systems, and the influence maximization problem is a recent hotspot to determine influential seeds from nodal members. Widespread applicable values can be found in marketing and information digging tasks, which boost more attention on related studies. Several diffusion models and seed determination techniques have been developed. Meanwhile, networked systems are threatened by sabotages and structural perturbances, and recent literature indicated that the robustness of the diffusion process is significant in daily applications, which can be modeled as the robust influence maximization problem. However, existing studies have not touched upon the node-based attack and its impact on the performance of seeds; corresponding robust seeds determination strategies are also lacked. For solving the robust influence maximization problem considering node-based attacks, a numerical measure is designed in this paper to assess the performance of given seeds. A sensitivity analysis is also conducted to test the impairing effect of several nodal importance metrics. Further, guided by the proposed measure, a memetic algorithm with the niching strategy has been devised to search for seeds with robust influential ability, termed NMA-RIM. Experiments on synthetic and real-world networks validate the competitiveness of NMA-RIM over existing algorithms, and the improved efficiency achieved by the niching strategy is also demonstrated. Meanwhile, the difference between selection results guided by the proposed measure and previous ones is shown via empirical analysis. As demonstrated by the obtained results, NMA-RIM outperforms existing approaches, and a better computational efficiency can be achieved. Competitive candidates can be provided for decision makers to solve information diffusion dilemmas.

Vulnerability analysis of urban road networks based on traffic situation

Traffic congestion is a global issue, which occurs during rush hour but also in situations of emergency causing massive congestion. This paper proposes a method for building a weighted road network by using the real-time traffic situation and the inherent characteristics of Urban Road Networks (URNs). To research the cascading failure vulnerability of URNs three kinds of node importance indexes are constructed from the structure, function, and traffic flow characteristics. Then the feasibility and validity of the proposed model are verified by taking Shanghai road networks (SRNs) as an example. The results indicate that the highest betweenness node-based attack causes the most damage to the SRNS of different types of attacks, and the SRNS cascade fails with the greatest speed and scale. Furthermore, we explore that the correlations between network vulnerability indicators, and suggest significant differences at different times during cascading failures of the weighted road network.

A Memetic algorithm for determining robust and influential seeds against structural perturbances in competitive networks

The influence maximization problem has attracted increasing attention in previous studies. Recent years have witnessed an enormous interest in the modeling, performance evaluation, and seed determination in different networked systems. Further, the competitive behavior between multiple influential groups within a network is developed to simulate the realistic marketing and propagation tasks. Powerful seeds can be detected to achieve considerable diffusion effects. Meanwhile, networks are operated in the presentence of disturbances, and the connectivity tends to be threatened by attacks and errors. Seeds with robustness against structural perturbances in competitive networks are significant for daily applications. However, little attention has been paid on evaluating the robustness of seeds towards competitive spreading scenarios, and an effective determination strategy is still lacked. In order to tackling the robust competitive influence maximization problem, a diffusion model considering competitive behaviors between spreading groups has been developed, and the spreading ability estimation technique is also given. Equipped with which, a robustness measure RCS is designed to evaluate the robustness of seeds under node-based attacks in a numerical form. The seed determination task has been modeled as a discrete optimization problem, and a Memetic algorithm containing several problem-orientated operators, termed MA-RCIM, is devised to solve the problem. Tested on several synthetic and real-world networks, MA-RCIM achieves satisfactory results for solving diffusion dilemmas, and shows superiority over existing approaches.

Vulnerability assessments of weighted urban rail transit networks with integrated coupled map lattices

This paper proposes an integrated coupled map lattices (ICML) to assess the node states and study the vulnerability of weighted urban rail transit networks (URTNs) subjected to the external disturbance R. Meanwhile, the passenger flow is refined as the passenger in-flow and out-flow of the station, and a new passenger flow redistribution rule is proposed to discuss the cascading failures of URTNs. Moreover, three parameters are adopted to analyze the vulnerability characteristics of URTNs subjected to cascading failures and Nanjing metro network is taken as the example to verify the feasibility and effectiveness of the presented model. The results show that there is a linear relationship between the node betweenness and edge betweenness, and URTNs are very vulnerable subjected to malicious attacks and become more and more vulnerable with the increase of the external disturbance. Furthermore, we find that the largest degree node-based attack (LDA) is more likely to result in cascading failures and the highest betweenness node-based attack (HBA) can cause the most damage to URTNs subjected malicious attacks. We also discover that the external disturbance R=2 is the critical threshold to smash the Nanjing metro network subjected to the largest degree node-based attack, and R=2.3 is the critical threshold to crush Nanjing metro network subjected to the highest betweenness node-based attack and the largest strength node-based attack.

An efficient layer node attack strategy to dismantle large multiplex networks

Network dismantling aims to identify the minimum set of nodes whose removal breaks the network into components of sub-extensive size. The solution to this problem is significant for designing optimal strategies for immunization policies, information spreading, and network attack. Modern systems, such as social networks and critical infrastructure networks, which consist of nodes connected by links of multiple types can be encapsulated into the framework of multiplex networks. Here we focus on the dismantling problem in multiplex networks under layer node-based attack, and propose an efficient dismantling algorithm based on network decycling. Experiments on synthetic and real-world networks show that the proposed algorithm outperforms existing algorithms by a considerable margin. We also show how the robustness of a multiplex network is affected by the interlayer degree correlation. Our results shed light on the design of more resilient network systems and the effective destruction of harmful networks.

Enhancing the power grid robustness against cascading failures under node-based attacks

In recent decades, many countries have suffered power outages and these accidents were often caused by a small disturbance, but because of the connection structure between the circuits, even a small mistake will cause the power grid cascade to fail and paralyze the network in a large area. In order to find a way to enhance the network robustness, this paper proposes three defense methods based on different ratio: the k-shell value ratio, degree ratio, and residual load ratio. We would compare the quality of the three defense methods by the relative size of the largest connected component after cascading failure. Besides, we also compare the time, the total number of crashed nodes, and the speed of cascading failure progress under three defense methods. From the experimental results, it is found that the defense methods based on the k-shell value ratio and the degree ratio have their own advantages in different situations.

Vulnerability Assessments of Urban Rail Transit Networks Based on Redundant Recovery

Urban rail transit has received much attention in the last two decades, and a significant number of cities have established urban rail transit networks (URTNs). Although URTNs have brought enormous convenience to the daily life of citizens, system failures still frequently occur, therefore the vulnerability of URTNs must be a concern. In this paper, we propose a novel measurement called the node strength parameter to assess the importance of nodes and present a redundant recovery scheme to imitate the system recovery of URTNs subjected to failures. Employing three malicious attacks and taking the Nanjing subway network as the case study, we investigated the network vulnerability under scenarios of different simulated attacks. The results illustrate that passenger in-flow shows the negligible impact on the vulnerability of the node, while out-flow plays a considerable role in the largest strength node-based attack. Further, we find that vulnerability will decrease as passenger out-flow increases, and the vulnerability characteristics are the same with the increase in the construction cost of URTNs. Considering different attack scenarios, the results indicate that the highest betweenness node-based attack will cause the most damage to the system, and increasing the construction cost can improve the robustness of URTNs.

Optimal Disintegration Strategy in Multiplex Networks under Layer Node-Based Attack

From social networks to complex infrastructures, many systems could be described by multiplex networks formed by a set of nodes connected via more than one type of links. Network disintegration, which is the problem of identifying a set of nodes or edges whose removal would maximize the network collapse, is significant for dismantling harmful networks. In this article, we consider the optimal disintegration strategy problem in multiplex networks and extend the attack mode to the layer node-based attack. An optimization model is proposed to search the optimal strategy of a multiplex network under layer node-based attack with fix attack length. Two types of strategies based on the information of multiplex nodes and layer nodes, respectively, are also given for comparison. Through experiments in both model networks and real networks, we found that the approximate optimal strategies could be identified by solving the model. The properties of the optimal strategies are also summarized.

Transportation functionality vulnerability of urban rail transit networks based on movingblock: The case of Nanjing metro

This paper employs system science and complex network theory to abstract the topological structure and to analyze the connectivity of urban rail transit networks. Meanwhile, movingblock technology is applied to calculate the transportation functionality and to investigate the static and dynamic vulnerability based on transportation functionality of urban rail transit networks. Considering Nanjing metro network as example, the results show that the connectivity of Nanjing metro network is very poor. For static failures, Nanjing metro network is very vulnerable when suffering malicious attacks, and the highest load node-based attacks can result in more damages than the largest degree node-based attacks. For dynamic failures, the results show that the transportation functionality becomes larger and larger with the increase of the control parameter of load capacity, which illustrates that the reliability becomes higher and higher with the increase of the construction cost. Therefore, we can declare that there exists a tradeoff between the reliability and construction cost of urban rail transit networks.

Topological characteristics of metro networks based on transfer constraint

Based on graph theory, this paper presents a topological heterogeneity and vulnerability analysis of metro networks where transfer constraint is taken into account. The statistical measurements based on minimal transfer times are defined, such as betweenness, the shortest path and the average transfer times. Based on above, on the one hand, heterogeneity of network is analyzed by adopting entropy theory; on the other hand, travel efficiency and connectivity based on effective paths are proposed to measure the topological vulnerability of metro network. The feasibility and rationality of the methods described above are verified through the Beijing metro network. The results show that the topological analysis neglecting transfer constraint would underestimate the heterogeneity and vulnerability of the metro network: the topological heterogeneity and vulnerability of Beijing metro network with considering transfer constraint are smaller than without considering transfer constraint; in the case of considering transfer constraint, with the scale expansion of network, travel efficiency and convenience increase, and topological heterogeneity and vulnerability of network decrease, but the connectivity of metro network is more vulnerable to node-based attack.

The robustness of multiplex networks under layer node-based attack.

From transportation networks to complex infrastructures, and to social and economic networks, a large variety of systems can be described in terms of multiplex networks formed by a set of nodes interacting through different network layers. Network robustness, as one of the most successful application areas of complex networks, has attracted great interest in a myriad of research realms. In this regard, how multiplex networks respond to potential attack is still an open issue. Here we study the robustness of multiplex networks under layer node-based random or targeted attack, which means that nodes just suffer attacks in a given layer yet no additional influence to their connections beyond this layer. A theoretical analysis framework is proposed to calculate the critical threshold and the size of giant component of multiplex networks when nodes are removed randomly or intentionally. Via numerous simulations, it is unveiled that the theoretical method can accurately predict the threshold and the size of giant component, irrespective of attack strategies. Moreover, we also compare the robustness of multiplex networks under multiplex node-based attack and layer node-based attack, and find that layer node-based attack makes multiplex networks more vulnerable, regardless of average degree and underlying topology.

Vulnerability analysis of the US power grid based on local load-redistribution

In this paper, local load-redistribution is employed to study the vulnerability of the US power grid subjected to attacks, and the initial load of power node is assumed as the linear summation of its degree and the sum of its neighbors’ degrees. Based on the simulation results, we find that with the decrease of the initial load of power node, the critical threshold of tolerance parameter increases subjected to the highest load node-based attack, but the critical threshold decreases subjected to the lowest load node-based attacks. Meanwhile, we discover that the critical threshold subjected to the lowest load node-based attack is larger than that subjected to the highest load node-based attack when the tunable parameter α∈[0.1,0.9]. Moreover, this paper compares the new model with the other two existing models, and the results illustrate that there are many similarities between these two existing models, but they are different from the new model presented in this paper. Furthermore, the infimum of tolerance parameter is proposed to portray the minimum cost of power grid, which can give a method to construct more robust power grids in the future.

Vulnerability Analysis of Urban Rail Transit Networks: A Case Study of Shanghai, China

Rail transit is developing rapidly in major cities of China and has become a key component of urban transport. Nevertheless, the security and reliability in operation are significant issues that cannot be neglected. In this paper, the network and station vulnerabilities of the urban rail transit system were analyzed based on complex network and graph theories. A vulnerability evaluation model was proposed by accounting metro interchange and passenger flow and further validated by a case study of Shanghai Metro with full-scale network and real-world traffic data. It is identified that the urban rail transit network is rather robust to random attacks, but is vulnerable to the largest degree node-based attacks and the highest betweenness node-based attacks. Metro stations with a large node degree are more important in maintaining the network size, while stations with a high node betweenness are critical to network efficiency and origin-destination (OD) connectivity. The most crucial stations in maintaining network serviceability do not necessarily have the highest passenger throughput or the largest structural connectivity. A comprehensive evaluation model as proposed is therefore essential to assess station vulnerability, so that attention can be placed on appropriate nodes within the metro system. The findings of this research are of both theoretical and practical significance for urban rail transit network design and performance evaluation.

An approach for modeling vulnerability of the network of networks

In this paper, a framework is given to model the network of networks and to investigate the vulnerability of the network of networks subjected to failures. Because there are several redundant systems in infrastructure systems, the dependent intensity between two networks is introduced and adopted to discuss the vulnerability of the interdependent infrastructure networks subjected to failures. Shanghai electrified rail transit network is used to illustrate the feasibility and effectiveness of the proposed framework. Because the rail network is dependent on the power grid and communication network, the corresponding power grid and communication network are also included in this system. Meanwhile the failures to the power grid and communication network are utilized to investigate the vulnerability of the rail network. The results show that the rail network strongly depends on the power grid and weakly depends on the communication network, and the transport functionality loss of the rail network increases with the increase of dependent intensity. Meanwhile the highest betweenness node-based attack to the power grid and the largest degree node-based attack to the communication network can result in the most functionality losses to the rail network. Moreover, the functionality loss of the rail network has the smallest value when the tolerance parameter of the power grid equals 0.75 and the critical nodes of the power grid and communication network can be obtained by simulations.

On link encryption against wiretapping attack in network coding

Network coding has been shown to offer an intrinsic security advantage in terms of node-based wiretapping attack. Previous literature explored the security advantage by defining and investigating the security level at an arbitrary intermediate node. As pointed out in other studies and observed by us, in order to achieve the security level at all intermediate nodes, it is necessary to have an admissible link encryption scheme to prevent all links from eavesdropping. “Admissibility” here promises that an adversary cannot obtain more meaningful (decoded or decodable) information about the original message than that disclosed at the node he controls. In this article, we study a similar problem but focus on link encryption. We propose an admissible link encryption scheme LNCLE; in conjunction with LNCLE, linear network coding achieves its security level at all intermediate nodes. In comparison with a trivial link encryption scheme (TLE) which is based on classical link encryption, LNCLE is more efficient in the sense that both key size and computation cost are greatly reduced.

Identifying Vulnerable Nodes of Complex Networks in Cascading Failures Induced by Node-Based Attacks

In the research on network security, distinguishing the vulnerable components of networks is very important for protecting infrastructures systems. Here, we probe how to identify the vulnerable nodes of complex networks in cascading failures, which was ignored before. Concerned with random attack (RA) and highest load attack (HL) on nodes, we model cascading dynamics of complex networks. Then, we introduce four kinds of weighting methods to characterize the nodes of networks including Barabási-Albert scale-free networks (SF), Watts-Strogatz small-world networks (WS), Erdos-Renyi random networks (ER), and two real-world networks. The simulations show that, for SF networks under HL attack, the nodes with small value of the fourth kind of weight are the most vulnerable and the ones with small value of the third weight are also vulnerable. Also, the real-world autonomous system with power-law distribution verifies these findings. Moreover, for WS and ER networks under both RA and HL attack, when the nodes have low tolerant ability, the ones with small value of the fourth kind of weight are more vulnerable and also the ones with high degree are easier to break down. The results give us important theoretical basis for digging the potential safety loophole and making protection strategy.

Networked characteristics of the urban rail transit networks

Urban rail transit networks (URTNs) have experienced rapid development and have been receiving much attention recently. In this paper, we comprehensively analyze the topological characteristics of urban rail transit networks, and we find that the average degrees of nodes of urban rail transit networks lie in the interval [2, 2.45], most of the average shortest path lengths between pairs of nodes belong to the interval [10, 16] and the average betweenness of nodes and edges linearly increase with the increase of the number of stations. Moreover, the cumulative probability distributions of the degree and shortest path length can be fitted by exponential distribution and Gauss distribution, respectively. The network failures of the urban rail transit networks are discussed and we also discover that the highest betweenness node-based attack is the most effective method to destroy the network.

Networked analysis of the Shanghai subway network, in China

Recently, cities have become larger and larger, and more and more people are living in large cities. This phenomenon has caused serious traffic congestion which is very detrimental to the development of large cities. In this context, the subway has become the most effective solution for relieving traffic congestion and subways have been constructed in many cities, so the reliability and robustness of subways should be guaranteed. In this paper, Shanghai subway network, in China, will be analyzed and investigated; the topological characteristics and functional properties can be studied in order to assess the reliability and robustness. The topological characteristics can be measured using several parameters; meanwhile the fraction of removed nodes of Shanghai subway network is discussed and compared against that for a random network, and the critical threshold of this fraction is obtained. Two novel parameters called the functionality loss and connectivity of subway lines are proposed for measuring the transport functionality and the connectivity of subway lines. Subway lines 4 and 7 are selected as examples for evaluating the connectivity of lines subjected to different attack protocols. This study indicates that the subway network is robust against random attacks but fragile for malicious attacks, and the highest betweenness node-based attacks can cause the most serious damage to subway networks among the different attack protocols.