Ad hoc网络信任模型的研究

利用基于身份的公钥系统和（t,n）门限密码,实现一个Ad hoc网络的信任模型。在该信任模型中,系统私钥由所有节点共享,任意t个节点一起来完成可信中心的功能,为任意节点生成私钥。并且,无需权威机构来进行初始化,在系统私钥保持不变的前提下,节点拥有的部分系统私钥和门限t的值可以随时更新。该信任模型满足Ad hoc网络拓扑结构经常变化和移动节点资源受限的特性,可以用于建立一个安全的Ad hoc网络。     

一种移动Ad hoc网的可靠性评估方法*

为了评估移动Ad hoc网的可靠性,综合考虑节点移动性引起的动态连接以及网络组件故障的因素,提出一种移动Ad hoc网的2-终端可靠性计算方法（MANET-RC）,并得到量化表达式。实验结果表明,移动Ad hoc网的可靠性不仅依赖节点、链路可靠性,还依赖于网络拓扑的冗余度和节点在网络中的分布。这为提升自组织网络的安全性能提供了理论依据。     

移动Ad hoc网络安全分簇综述

移动Ad hoc网络是由移动节点组成的无线移动通信网络,它具有动态拓扑、无线通信的特点,但又易受到各种安全威胁。规模较大的移动Ad hoc网络可以用分簇的方法来减少路由和控制开销,并提高网络的可扩充性。综合分析了以安全为部分或全部目的的移动Ad hoc网络分簇方法研究的最新进展。首先分析了移动Ad hoc网络的特点、体系结构和面临的安全威胁,然后将较大规模移动Ad hoc网络的安全分簇方法分为3个重要方面:认证模型、信任度量和不良节点发现。对每个方面的一些典型方案进行了分类论述和综合比较。最后指出了下一步研究中应当着重考虑的问题。     

试论Ad hoc网络的安全策略

Ad hoc是一种完全由无线连接的移动节点所构成的网络。相比于传统的网络,Ad Hoc网络更易受到各种安全威胁和攻击,用于传统网络的安全解决方案不能直接应用于Ad hoc网络,现存的用于Ad hoc网络的大多协议和提案也没有很好解决安全,本文对Ad hoc网络的安全问题、策略和机制进行了一些有益的探讨。     

Small-World在确定性Ad hoc网络信任模型中的应用

该文首先介绍了小世界（Small-World）现象的起源、发展现状及在现实中的应用.随后介绍了一种基于证书链的Ad hoc网络的信任模型.然后根据Ad hoc网络拓扑结构确定性理论,为了在Ad hoc网络中实现“Small-World”现象,使得网络中任意节点之间的信息传输中所经历的中间节点尽可能少,从而节约Ad hoc网络中存在的信息传输对节点计算和电力等资源的不必要的消耗.基于上述理论及对现实应用的考虑,该文建立了一个模型,并在NS-2上进行了仿真实验,最后对该模型的安全性方面进行了一些讨论.     

Ad hoc网络安全技术简介

Ad hoc网络是一种没有有线基础设施支持的移动网络,网络中的节点均由移动主机构成。由于节点的移动性导致网络拓扑结构不断变化,节点通信完全依靠无线链路,相对于有线网络在安全性上面临更大的挑战。本文根据Ad hoc网络面临的安全问题,分析了Ad hoc网络中常见的攻击方式,并集中讨论了Ad hoc网络的安全路由、密钥管理等关键问题。     

二部无标度网络上病毒传播模型和免疫策略研究

针对计算机网络上的病毒传播问题,提出一种二部无标度网络,其节点分为客户机和服务器两类。在二部无标度网络上应用易感-感染-易感(SIS)传播模型,采用率方程的方法研究二部无标度网络上病毒的状态转移和临界行为,得出客户机感染密度与服务器感染密度的关系式。在SIS模型的基础上利用免疫策略,针对相同的网络拓扑和病毒传播模型,分析比较免疫策略的免疫功能,并给出支持理论结果的数值模拟,结果验证了随机免疫、节点度免疫与相识点免疫策略都具有防御病毒传播的功能,并且防疫能力依次增强。     

一种基于Agent的Ad hoc网络路由算法

Ad hoc网络因其具有分布式、无中心、自组织、节点可以移动等特点,在军事通信、灾后紧急救援、传感器网络、局域网、车辆通信等方面有着广阔的应用前景,成为研究领域的一个热点.但同时由于Ad hoc网络拓扑结构的动态变化,使得作为Ad hDc网络关键技术之一的路由算法的实现较为困难.提出了一种基于Agent的Ad hoc网络路由算法,设计并实现了4种Agent.该算法通过在Ad hoc网络中加入一定数量的移动Agent来进行路由探寻,一方面降低了网络负载,另一方面降低了网络发送数据的时延.其实质是在现有的表驱动路由算法和按需驱动路由算法之间寻求一个折中.     

计算机病毒免疫信息网络发布算法

结合传统的网络拓扑结构和单机节点访问率,改进了无标度网络结构下病毒传播模型,进而提出了新的目标节点的定义。根据新的网络病毒传播模型,提出了一种基于门限判决的计算机病毒免疫算法。利用OPENET仿真实验平台,比较了该算法与以往免疫算法的性能和效率。仿真结果表明该算法免疫更少的节点即可达到全网免疫状态,且时间更快,效率更高。因此,该文算法能有效遏制病毒大规模爆发和传播,具有一定的社会意义和经济价值。     

Ad hoc网络的安全性分析

Ad hoc网络是由一组无线移动节点组成的集合,这些节点可以在没有任何网络基础设施和中心联网设备的情况下互相通信。由于其自身的动态拓扑、开放媒质、生存周期短等特点,Ad hoc网络极其容易受到攻击,安全问题是实施应用的关键。本文讨论了Ad hoc网络的基本概念、特点及安全需求,分析了它存在的安全问题,并提出了相应的安全机制。对Ad hoc网络的安全性问题做了具体的研究。     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

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.     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

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.