基于动态包过滤的RoQ攻击防御策略

以离散傅立叶变换为基础,对TCP数据流采样时间域序列x(n)进行(0,1)序列标准化,依据RoQ攻击周期性等特点检测RoQ攻击,提出了一种基于动态包过滤的RoQ攻击防御策略,并给出了该防御策略的实现算法。     

骨干网络中RoQ攻击的监测、定位和识别

降质（reduction of quality ,RoQ）攻击是一种非典型拒绝服务攻击,它利用TCP自适应机制的安全漏洞能够显著降低或抑制TCP服务质量,且具有很强的隐蔽性。现有的研究集中在针对单条网络链路上的攻击和检测。但是,Ro Q攻击的对象并不局限于此,它既可以对单条链路发动攻击,也可以有选择的对多条链路（甚至整个网络）发起攻击,造成更大的危害,所以需要有一种能够从网络全局角度分析和识别的方法。为此,提出了一种基于骨干网络流量分析的异常监测、定位和识别的方法M IL‐Ro Q （monitoring ,identifying and locating the RoQ attack in backbone network ）。主要使用主成分分析（principal component analysis ,PCA ）和频谱分析（spectrum analysis）技术对骨干流量进行流量建模分析,从全局角度监测网络流量变化情况,能够同时分析和判断多条链路的异常情况,并能准确识别出Ro Q攻击。使用了CERNET骨干网络数据进行实验分析,结果表明该方法能够有效地定位和识别RoQ 攻击;同时,攻击识别时只需要使用局部的流量数据,因而能显著降低计算量和复杂度。     

基于战略博弈的DDoS攻防绩效评估方法

提出一种基于战略博弈的DDoS攻防策略绩效评估方法,针对当前DDoS攻击防范策略中基于速率限制的防范机制,利用博弈论方法对DDoS攻防双方进行建模,对LACC和Pushback防范策略的绩效进行定量评估,分析不同策略在不同攻击场景下的性能和防范效果。针对典型的DDoS攻击场景,利用网络仿真工具进行模拟实验,通过计算攻防双方的混合战略纳什均衡评估防范策略的绩效验证该方法的适用性和有效性。     

基于能量有限型无线传感网的恶意软件攻防优化策略

本文针对目前无线传感网络中恶意软件模型化工作的不足,从攻击与防御角度出发,考虑了攻击扫描速率对于攻防优化策略的不同意义,同时考虑了无线传感节点能量有限的特征,在传统恶意软件传播模型的基础上提出了一种改进的无线传感网络恶意软件攻防优化模型。该模型在传统SIR传播模型基础上进行扩展,考虑了免疫与修复的不同因素,最终给出了攻防优化评估方案。通过仿真实验表明,该攻防优化评估方案能够高效地描述攻击扫描参数对恶意软件在无线传感网络中攻击与防御各自效果最大化的关键影响。     

基于攻防树的APT风险分析方法

针对目前缺少APT攻击中系统威胁风险评估理论模型的问题,提出了一种基于攻防树的网络攻击风险分析方法。将APT攻击过程分为攻击阶段与防护阶段,定义不同阶段内的参数计算方法,首先通过漏洞收集和攻击事件捕获构建攻击行为节点,并将防护对策映射为防护行为节点;其次形式化定义了漏洞成功利用概率、攻击成本、防护成本和系统损失度等参数,利用ADTool工具生成攻防树和节点参数值;然后引入攻击回报与防护回报的概念,作为系统风险分析的依据;最后构建了基于攻防树的攻击风险分析框架,并通过一个APT攻击实例对框架效果进行了验证。计算结果表明,可通过攻击回报等参数数值的变化评估采取防护对策的效果。该方法对攻防双方策略互相影响的场景描述更加贴近实际,实现了系统威胁风险度分析与防护策略效果评估的目的。     

面向多种攻击的无线传感器网络攻防博弈模型

传统的无线传感器网络（wireless sensor network,WSN）攻防模型一般只考虑一种攻击行为,而在真实情况下,恶意节点为了提高攻击成功率,常常会同时采取多种攻击方式,并且能够根据对方的防御情况灵活调整攻击策略。针对这种情况,提出了一种面向多种攻击的无线传感器攻防博弈模型,分别对WSN在外部攻击、内部攻击和混合攻击下的攻防博弈过程进行研究。利用不完全信息博弈理论分别建立了三种攻击下的博弈模型,通过对博弈模型的分析与求解,得到了攻防双方的最优策略,并利用数值模拟方法对理论结果进行了验证。研究结果对WSN中入侵检测系统（intrusion detection system,IDS）的设计具有现实指导意义。     

基于动态攻击图的网络安全实时评估

针对网络安全评估对实时性及可视化的需求,提出了一种基于动态攻击图的实时评佑方法。首先通过采集网络的脆弱性、网络拓扑、资产价值等安全属性信息,同时提取入侵检测系统的报警信息、防火墙策略、安全管理等动态攻防对抗信息,生成动态攻击图,并实时调整防御手段对网络进行及时、有效的保护,实时地对网络系统的安全状态进行评估,并采用可视化的方法展现评估结果,在此基础上给出整体安全策略调整建议。最后通过实验证明了本方法的可行性和有效性。     

网络攻防演练平台的设计与实现

针对网络攻防课程实验环境的构建问题,本文设计了作为网络攻防课程的教学和实验辅助环境的网络攻防演练平台。以通过建立课堂演示和课程相关的验证性实验攻击标靶搭建攻击测试环境为目标进行模块化的设计,同时,针对支持网络攻防对抗演练的支撑环境进行设计,对推进网络攻防课程教学和提高学生动手能力具有重要意义。     

SQL注入攻击方法及预防措施的研究

随着网络应用的日益广泛,网络安全意识的增强,人们对网络安全的重视程度越来越高。与此同时,网络攻击也不断变换目标和攻击方法。现在,针对Web应用系统的攻击已经成为网络安全攻防新焦点。而在Web应用系统的所有攻击中,SQL注入成为web应用系统的严重安全隐患。本文对SQL注入攻击进行了综合概述,并从多个角度提出了相应的攻击方法和防范措施。     

融合攻击图和博弈模型的网络防御策略生成方法

近些年威胁网络安全的事件日趋频繁,黑客的攻击手段越来越复杂,网络安全防护的难度不断增加。针对实际攻防环境中攻击策略复杂多变和攻击者不理性的问题,文章将攻击图融入攻防博弈模型,并引入强化学习算法,设计了一种网络主动防御策略生成方法。该方法首先基于改进攻击图的网络脆弱性评估模型,成功压缩策略空间并有效降低建模难度,然后对网络攻防进行博弈模型构建,将攻击者和防御者对网络的攻防策略问题设计为一个多阶段的随机博弈模型,引入强化学习Minimax-Q设计了自学习网络防御策略选取算法。防御者在经过对一系列的攻击行为学习之后,求解出针对该攻击者的最优防御策略。最后,本文通过仿真实验验证了该算法的有效性和先进性。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

Call for Papers The 6^th International Conference on Grid and Cooperative Computing

Recent years have seen rapid advances in various grid-related technologies, middleware, and applications. The GCC conference has become one of the largest scientific events worldwide in grid and cooperative computing. The 6th international conference on grid and cooperative computing (GCC2007) Sponsored by China Computer Federation (CCF),Institute of Computing Technology, Chinese Academy of Sciences (ICT) and Xinjiang University ,and in Cooperation with IEEE Computer Soceity ,is to be held from August 16 to 18, 2007 in Urumchi, Xinjiang, China.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

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