Exact and heuristic algorithms for solving the generalized minimum filter placement problem

We consider a problem of placing route-based filters in a communication network to limit the number of forged address attacks to a prescribed level. Nodes in the network communicate by exchanging packets along arcs, and the originating node embeds the origin and destination addresses within each packet that it sends. In the absence of a validation mechanism, one node can send packets to another node using a forged origin address to launch an attack against that node. Route-based filters can be established at various nodes on the communication network to protect against these attacks. A route-based filter examines each packet arriving at a node, and determines whether or not the origin address could be legitimate, based on the arc on which the packet arrives, the routing information, and possibly the destination. The problem we consider seeks to find a minimum cardinality subset of nodes to filter so that the prescribed level of security is achieved. We formulate a mixed-integer programming model for the problem and derive valid inequalities for this model by identifying polynomially-solvable subgraphs of the communication network. We also present three heuristics for solving the filter placement problem and evaluate their performance against the optimal solution provided by the mixed-integer programming model. The authors gratefully acknowledge the comments of two anonymous referees, whose input led to an improved version of this paper. Dr. Smith gratefully acknowledges the support of the Office of Naval Research under Grant #N00014-03-1-0510 and the Defense Advanced Research Projects Agency under Grant #N66001-01-1-8925.     

优秀男篮大前锋进攻中持球动作结构特征分析

采用文献资料、录像观察、数理统计等方法,对中外优秀男篮大前锋的身体形态指标进行统计分析,并研究其在阵地进攻中的持球动作结构特征.结果表明:世界优秀男篮大前锋的身体形态指标均有不同程度的增长,其阵地进攻中持球动作的结构比较复杂和多样化;而中国男篮优秀大前锋的动作结构相对简单、单调,部分动作运用不够合理.     

Out of the Frying Pan into the Fire: Behavioral Reactions to Terrorist Attacks

A low-probability, high-damage event in which many people are killed at one point of time is called a dread risk. Dread risks can cause direct damage and, in addition, indirect damage mediated though the minds of citizens. I analyze the behavioral reactions of Americans to the terrorist attacks on September 11, 2001, and provide evidence for the dread hypothesis: (i) Americans reduced their air travel after the attack; (ii) for a period of one year following the attacks, interstate highway travel increased, suggesting that a proportion of those who did not fly instead drove to their destination; and (iii) for the same period, in each month the number of fatal highway crashes exceeded the base line of the previous years. An estimated 1,500 Americans died on the road in the attempt to avoid the fate of the passengers who were killed in the four fatal flights.     

Wholeness of Self Workshops:

No abstract available for this article.     

大型文体活动防范恐怖袭击的对策思考

大型文体活动具有参加人员多、成分复杂、分布密集的特征,加之不确定性因素的存在很容易成为恐怖分子袭击的主要目标,因此,相关部门必须具备防范意识,事前做好防范、事发做好应付、事后做好处置工作,采取收集相关情报、加强反恐宣传、加强安全检查、整治社会环境、进行实践演练等措施。     

SQL注入攻击原理与防范

随着互联网技术的高速发展,基于B／S模式的Web应用程序得到了广泛的应用,当这些Web应用程序没有对接收到的数据进行合法性审查过滤时,系统便存在安全隐患．SQL注入正是利用了这一漏洞对数据库进行攻击的．文章研究了原理,并就对其如何防范讨论了几种方法．     

On suicide bombings: questioning rationalist models and logics of gender

The theories of rational choice have been widely used in analysing suicide bombings. Such a use is here critically examined along three lines. First, the limits of this theoretical framework when applied to sacrificial violence are assessed and especially the internal contradictions which appear with the notion of ‘symbolic posthumous rewards’. Second, differences emerge in the use of rational choice theory when the focus is upon female suicide bombers. Indeed, deprivation theories come then to the fore, the idea of personal crisis and the impact of patriarchal social relationships. This switch in the analysis, which does not seem based on differences in the data, confirms gender studies which underline the specific difficulty to envisage female political violence. Finally, to go beyond both reductionisms, a compared analysis of suicide attacks in Chechnya, Iraq and Israel/Palestine is proposed. It aims at restituting the context of action and the narratives at work, making a clear distinction between two levels of analysis, the one of the organizations, which can largely be understood in terms of their strategic rationale, and that of the suicide bombers themselves, for whom it seems more heuristic to use the concepts of narratives and horizons of expectation.     

A Framework for Estimating the Adverse Health Effects of Contamination Events in Water Distribution Systems and its Application

Intentional or accidental releases of contaminants into a water distribution system (WDS) have the potential to cause significant adverse health effects among individuals consuming water from the system. A flexible analysis framework is presented here for estimating the magnitude of such potential effects and is applied using network models for 12 actual WDSs of varying sizes. Upper bounds are developed for the magnitude of adverse effects of contamination events in WDSs and evaluated using results from the 12 systems. These bounds can be applied in cases in which little system‐specific information is available. The combination of a detailed, network‐specific approach and a bounding approach allows consequence assessments to be performed for systems for which varying amounts of information are available and addresses important needs of individual utilities as well as regional or national assessments. The approach used in the analysis framework allows contaminant injections at any or all network nodes and uses models that (1) account for contaminant transport in the systems, including contaminant decay, and (2) provide estimates of ingested contaminant doses for the exposed population. The approach can be easily modified as better transport or exposure models become available. The methods presented here provide the ability to quantify or bound potential adverse effects of contamination events for a wide variety of possible contaminants and WDSs, including systems without a network model.     

Developing the eclectic paradigm as a model of global strategy: An application to the impact of the Sep. 11 terrorist attacks on MNE performance levels

We expand the eclectic paradigm into a model of global strategic management and apply the latter to the analysis of the impact of the Sep. 11th terrorist attacks on the MNEs' performance to investigate the effect of exogenous shocks on the global strategies of firms. First, we integrate MNE resources and capabilities, strategy, and structure with the eclectic paradigm. Then we focus specifically on location attractiveness to examine how MNEs adjust internal factors with the exogenous distortions caused by an extreme environmental shock. We suggest that this adjustment is carried out at four levels: resources and capabilities, strategy, structure, and choice of location which jointly determine MNEs' performance. Although we restrict the application of this model of global strategic management to the post-Sep. 11th, our model may be applied to other extreme events that change, at least partly, the worldwide, or regional, economic order.     

香港“掷镪案”研究及其对我国城市公共安全的启示

在广泛搜集香港高空投毒事件"掷镪案"资料的基础上,通过进一步整理、深入分析应对此类突发事件的城市公共安全机制,提出可供我国建构城市公共安全机制借鉴的经验教训。