基于连通可靠度的交通网络重要路段评价算法

如何提高交通网络的连通可靠度,是交通领域的一个重要问题,通过提高重要路段的连通度来提高交通网络的连通可靠度是一个重要的方法。引入复杂网络理论中接近度、关键度等概念,结合交通网络中的流量分布,利用图的对偶理论识别出交通网络的重要路段,提出评价交通网络中路段重要度的算法,通过实例验证所提方法的有效性和应用价值。     

第四方物流多到多弹复性网络设计

为了使第四方物流(4PL)能够提供安全、有效的物流服务,提出多个供需点对之间物流配送任务下的4PL弹复性网络设计模型。建立以总物流成本最小化为目标的优化模型,考虑物流服务节点和运输线路的中断,通过构建备用路径实现弹复性,以主路径和备用路径共用的服务节点和运输线路的数量作为弹复性指标,设计人工蜂群算法对模型进行求解,并对问题模型中的重要参数进行分析。仿真结果表明,人工蜂群算法能够对问题进行有效求解。     

考虑相继故障的物流耦合网络节点重要度评估*

物流网络是由任务网络和交通网络构成的耦合网络,为有效识别和保护关键节点,避免耦合网络相继故障引发的大规模系统崩溃,提出了考虑耦合网络相继故障的节点重要度评估方法。基于物流任务的效率要求设计了物流任务和交通双层均衡规划模型并将移除节点造成的效率损失和拥堵程度分别作为衡量节点重要度的主要和辅助标准。通过仿真试验验证了该方法的可行性与准确性。与其他方法相比,该方法能有效识别失效后引发关联网络大规模相继故障的节点,从而为关键基础设施的保护提供依据。     

基于节点交互度的社会网络链路预测

链路预测是通过已知的网络拓扑和节点属性挖掘未来时刻节点潜在关系的重要手段, 是预测缺失链路和识别虚假链路的有效方法, 在研究社会网络结构演化中具有现实意义. 传统的链路预测方法基于节点信息或路径信息相似性进行预测, 然而, 前者考虑指标单一导致预测精度受限, 后者由于计算复杂度过高不适合在规模较大网络中应用. 通过对网络拓扑结构的分析, 本文提出一种基于节点交互度(interacting degree of nodes, IDN)的社会网络链路预测方法. 该方法首先根据网络中节点间的路径特征, 引入了节点效率的概念, 从而提高对于没有公共邻居节点之间链路预测的准确性; 为了进一步挖掘节点间共同邻居的相关属性, 借助分析节点间共同邻居的拓扑结构, 该方法还创新性地整合了路径特征和局部信息, 提出了社会网络节点交互度的定义, 准确刻画出节点间的相似度, 从而增强网络链路的预测能力; 最后, 本文借助6个真实网络数据集对IDN方法进行验证, 实验结果表明, 相比于目前的主流算法, 本文提出的方法在AUC和Precision两个评价指标上均表现出更优的预测性能, 预测结果平均分别提升22%和54%. 因此节点交互度的提出在链路预测方面具有很高的可行性和有效性.     

区域交通信号系统节点分析及优化策略研究

SCOOT、SCATS等区域交通信号控制系统的关键路口通常根据交叉口交通流量、道路联接数等指标来确定,很难保证“蓄意”交通事件下区域网络运行的有效性。鉴于城市交通网络的无标度特性,以路段阻抗为权重将城市交通网络抽象为复杂加权网络,提出以网络凝聚度为指标的加权节点收缩方法,评估交叉口节点的重要性,解决区域交通网络hub点的选择问题,并用实例说明该方法的有效性,进而以SCATS系统为对象提出基于hub点选择的系统优化策略。     

度相关性对复杂网络目标控制的影响

随着信息时代的来临,复杂网络在生活中扮演着越来越重要的角色,例如社交网络、电力网络、交通网络等。对网络的控制引起了广泛的关注,而网络的目标控制是其中一类重要问题。通过模拟退火算法,研究在目标控制前提下度相关性对于目标控制的影响。实验表明,入度-入度相关性与出度-出度相关性对网络目标可控性的影响几乎一致,随着入度-入度相关性逐渐增加,驱动节点的比例先减少后增加;出度-入度相关性对于网络驱动节点比例的影响较大,随着出度-入度相关性逐渐增加,驱动节点的比例逐渐减少;而入度-出度相关性对于网络驱动节点比例几乎没有影响。     

结合相似度的新型加权网络模型

许多实际复杂网络都可以采用加权网络模型描述.现有加权网络多以节点强度作为择优连接的概率，而未考虑节点之间内在属性的相似也会增加两个节点连接的概率.基于典型的BBV加权网络模型，提出一个结合相似度的新型加权网络模型，改进了已有模型的连边增长方式和择优连接机制，提出了一种权重自适应演化机制.通过提出节点之间相似度的概念，网络演化中同时兼顾节点强度与相似度进行择优连接.网络增长时，既考虑了新节点与已有节点之间增加连边，又考虑到两个已有节点之间增加连边.理论分析和实验结果表明，该网络模型具有无标度特性和小世界特性，节点度和节点强度均具有幂律分布规律，具有更广泛的应用场景.     

基于重叠盒覆盖算法的节点重要度评估

由于单一的节点评估方法存在不足,在融合复杂网络的局部特征以及全局特征前提下,提出了一种基于重叠盒覆盖算法的节点重要度评估方法.该方法利用重叠中心性对网络中的节点进行重要度排序,并且与其他不同中心性方法在复杂网络数据集中的节点排序方法进行比较;利用susceptible-infected (SI)模型模拟不同中心性方法前10个节点的传播能力,在此基础上以肯德尔系数进行比较,肯德尔系数越大表明相关性越高.实验结果表明,与其他中心性方法相比,重叠中心性得到的初始节点集合的累积平均感染能力高于其他中心性方法,并且与SI模型具有较高的相关性,该方法对于节点重要度评估是有效并且可行的.     

基于电路模型的复杂网络节点相似度度量

针对复杂网络中节点相似度度量的问题,在物理学相关知识的启发下,运用相关模型提出了一种基于物理学中电路模型的节点相似度度量的方法.纯粹从节点间的链接图结构来计算节点间的相似度,节点间的相似度用物理学电路模型中的电阻来衡量:电阻越小,相似度越大;电阻越大,相似度越小.实验结果表明了该方法的有效性和合理性,提供了一种借用其它学科方法来解决复杂网络节点相似度度量的新颖方法.     

基于相似度传播的复杂网络间节点匹配算法

提出了一种基于相似度传播的复杂网络间节点匹配方法.引入节点相似度传播过程,使得初始的相似度信息能够按网络拓扑结构传播到全局,从而能够充分利用有限数目已匹配节点对所提供的相似度信息.该传播过程的稳态分布与一个大矩阵的主特征向量等价,可采用幂方法的迭代形式来高效求解,最后利用图论中的KM(Kuhn-Munkres)算法来抽取最终的匹配节点对.以四种不同结构的网络节点匹配实验为例,对本文算法进行了测试和验证.实验统计结果表明,本文方法显著提高了节点匹配的精度.     

In Search of Concerted Strategies for Competitive and Resilient Regions

The European space-economy represents a complex system with a great internal heterogeneity, intensive socioeconomic interactions and differential growth trajectories among countries and regions. The present study aims to investigate the connectivity between spatial competitiveness and resilience in Europe and seeks to design an operational framework for concerted strategies of competitive and resilient regions. To assess the linkage between resilience and competitiveness, we have developed a new measure, viz. the Resilience and Competitiveness Index (RACI) as a function of two constituent sub-indices: Resilience and Competitiveness. This approach is tested on the basis of detailed data on European regions. The empirical results from 268 EU NUTS2 regions offer a solid anchor point for the proposed operational framework for concerted development strategies of competitive and resilient regions. Our research distinguishes and proposes several systematic types of concerted regional strategies according to the performance of a region measured by Resilience and Competiveness sub-indices. A key result of the study is the design of an operational constellation for strategic regional policy evaluation, with a major added value for policy- and decision-making purposes. The use of official data from Eurostat and of standard indicators in our research assures continuity and consistency with the official Regional Competitiveness Index (RCI) classification and measurement, so that policy makers are able to compare the performance of their regions over time and to develop proper concerted strategies accordingly. The clear evidence of a connectivity between regional competitiveness and resilience may help to develop a governance approach that balances competitiveness (mainly represented by productive assets) with resilience (mainly represented by sustainability and ecological awareness) and thus to deal with the complexity in socioeconomic systems.

     

Stochastic measures of resilience and their application to container terminals

While early research efforts were devoted to the protection of systems against disruptive events, be they malevolent attacks, man-made accidents, or natural disasters, recent attention has been given to the resilience, or the ability of systems to “bounce back,” of these events. Discussed here is a modeling paradigm for quantifying system resilience, primarily as a function of vulnerability (the adverse initial system impact of the disruption) and recoverability (the speed of system recovery). To account for uncertainty, stochastic measures of resilience are introduced, including Time to Total System Restoration, Time to Full System Service Resilience, and Time to α%-Resilience. These metrics are applied to quantify the resilience of inland waterway ports, important hubs in the flow of commodities, and the port resilience approach is deployed in a data-driven case study for the inland Port of Catoosa in Oklahoma. The contributions herein demonstrate a starting point in the development of a resilience decision making framework.     

浅析网络安全风险评估问题

网络安全性能的预先识别、对网络整体的安全性能的掌握对网络安全非常重要。该文主要就网络安全风险的系统体系结构设计进行探讨,主要讨论了脆弱性扫描客户方子系统设计、脆弱性扫描服务器以及系统风险评估子系统设计三部分,对于深化网络安全风险评估具有一定作用。     

The Architecture of Connectivity: A Key to Network Vulnerability,Complexity and Resilience

This paper highlights the relevance of connectivity and its architecture as a general conceptual framework which underlies and integrates the concepts of network vulnerability, complexity, and resilience. In particular, it will be pointed out that connectivity architecture can be considered an explicit key element for network vulnerability and shock propagation. While the relevance of the various connectivity configurations is not clearly emphasised in the dynamic complexity models of the space-economy, it appears to play a primary role in network analysis. In this regard, the emerging recognition of connectivity architecture in relation to hubs ? and hierarchies of hubs ? in a complex network will help the enhancement of network resilience. The paper develops as follows. First, the notion of network vulnerability, which refers not only to the phenomenon of shocks, but also to the propagation of shocks in a network, will be examined. Here it appears that modelling vulnerability and shock propagation, also jointly with cascading disaster models, is strongly based on connectivity issues. The question is: How can conventional (complex) system dynamic modelling, as well as network modelling, take into account these shocks and connectivity dynamics from the methodological viewpoint? A review in this respect shows how connectivity is a ‘hidden’ element in these complexity models, for example, in chaos or (dynamic) competition models, where interaction parameter values might lead to vulnerable domains and chaotic behaviour. On the contrary, connectivity and its various topologies have a distinct, primary role in network analysis. The issue of network resilience appears therefore to be the ‘response’ to vulnerability and chaos, calling for robustness and stability of the network in the presence of shocks and disruptions. Resilience analysis refers to the speed at which a network returns to its equilibrium after a shock, as well as to the perturbations/shocks that can be absorbed before the network is induced into some other equilibrium (adaptivity). Connectivity is relevant here, but not often considered in spatial economics. In order to reach a unified methodological framework, attention will finally be paid to a complementary analysis of the (dynamic) concepts of vulnerability and resilience. In this light, chaos models/properties might be seen in a positive perspective, since small changes can lead to uncertain and unstable effects, but also, thanks to connectivity, to new equilibria which are not necessarily negative. Thus, the architecture of connectivity, in its interdisciplinary insights, can be considered as a fundamental (and analytical) approach for identifying vulnerability and resilience patterns in complex networks.

     

Proposal of resilience assessment by focusing on pliability

Resilience is a concept which presents the strength of mind necessary to adopt the difficulties and to recover from negative psychological state. The assessment for resilience has been assessed by using interview and questionnaire which depend on subjectivity of participants. Though the objective assessment for resilience is expected to advance the biofeedback treatment, neither effective method nor instrument have been developed. Then this study focuses on the pliability as one of aspects of resilience and experimentally verifies whether it becomes a novel index for resilience or not.     

Building Edge-Failure Resilient Networks

We consider the design of resilient networks that are fault tolerant against link failures. Resilience against link failures can be built into the network by providing backup paths, which are used in the eventuality of an edge failure occurring on a primary path in the network. We consider several network design problems in this context; these problems are motivated by the requirements of current high-speed optical networks. In all the following problems the objective is to provide resilience in networks while minimizing the cost incurred. The main problem under consideration in this paper is that of backup allocation: this problem takes as its input an already provisioned primary network and a parameter k, and allocates backup capacity on the edges of the underlying network so that all the demand can be routed even in the presence of k edge failures. We also consider a variant of this problem where the primary network has a tree topology, and it is required that the restored network retains a tree topology. We then address the problem of simultaneous primary and backup allocation: we are given specifications of the traffic to be handled, and the goal is to provision both the primary as well as the backup network. Finally, we investigate a single-commodity problem motivated by a pragmatic scenario in which the primary network is not known in advance and demands between source--sink pairs arrive online.     

网络安全综述

随着计算机网络的不断发展，全球信息化已成为人类发展的大趋势，但由于计算机网络具有联结形式多样性、终端分布不均匀性和网络的开放性、互连性等特征，致使网络易受攻击，所以网上信息的安全和保密是一个至关重要的问题。无论是在局域网还是在广域网中，都存在着自然和人为等诸多因素的脆弱性和潜在威胁。网络的安全措施应是能全方位地针对各种不同的威胁和脆弱性，这样才能确保网络信息的保密性、完整性和可用性。     

网络弹性与恢复机制的研究综述

当网元故障或遭受攻击而失效时,网络性能下降,网络的拓扑结构也被破坏甚至崩溃.网络弹性描述在网元失效时网络功能和结构的恢复能力.针对不同网络类型和失效模式,研究者提出了多种网元恢复机制用于增强网络弹性,并建模分析如何减少网络失效的可能性,这对于现实系统的管理和维护具有重要的指导意义.本文首先简要介绍了网络失效和网络弹性的...     

Performance optimization of integrated job-driven and resilience factors by means of a quantitative approach

Job-driven factors affect overall productivity and describe the characteristics influencing human performance. Resilience engineering (RE) is the capability of systems and groups to cope with disturbances and disruptions to enhance their performance. This study employs data envelopment analysis (DEA) approach to optimize the overall performance of a ceramic tile company by considering resilience and job-driven factors. The required data were collected via a standard questionnaire whose reliability was examined by statistical methods. In this regard, sensitivity analysis was performed to determine the most important factors. DEA results showed that job stress, job burnout, and management commitment play a central role in the investigated system. The overall results indicated that job-driven factors have a higher weight than resilience factors. This is one of the first studies that concurrently examine job-driven and resilience factors. Second, the present study uses DEA method in a ceramic tile manufacturer to achieve optimum performance. Third, the weights of all factors are computed for optimum redesign and re-engineering. Fourth, decision-makers may identify weak areas and strong points of their systems with respect to job-driven and resilience factors.     

Risk assessment and resilience of critical communication infrastructure in railways

This paper discusses the significant findings of an extended risk assessment of the key communication infrastructure used in emergency communication in railways in Norway. The initial risk assessment was performed in 2008. Resilience was explored as a strategy in the risk assessment to improve safety, security, and quality of service. We have reviewed the results in 2010, documenting mitigating actions and the effect of the actions. In addition, the development of safety and security culture has been evaluated. The risk assessment was based on a socio-technical approach, which considers technical, organizational, and human factors. Action research was used as a method to improve the scope and commitment of the risk assessment. It is suggested that organizational collaboration supported by the action research approach has aided in prioritizing the key mitigating actions, based on improved understanding and commitment. The high stability of the GSM-R system has supported safety of operations in the period. One of the identified unwanted incidents occurred in 2010 and gave credibility to the risk assessment. The risk assessment process seems to have sustained the safety and security culture and improved the knowledge of emergency response supporting resilience. The resilience of the total system seems to have been improved. The main contributions of this article are the empirical results of a risk assessment extended with resilience and suggested indicators related to resilience. In addition, it is suggested that exploration of resilience and action research improves the quality and effect of the risk assessment. Risk assessments in a complex setting with uncertainty should explore resilience as a strategy and explore action research to improve understanding and learning among the stakeholders.