基于路由选择的防搭线窃听安全网络编码

相对于传统的以路由为基础的网络理论,网络编码技术有着许多特点和优势。与此同时,它也遭受着各种各样的网络攻击,其中搭线窃听攻击就是最典型的攻击之一。提出一种基于路由选择的防搭线窃听安全网络编码方法,在已知被窃听链路位置(不可信链路位置)的情况下,对被窃听链路的传送消息进行分析。在保证网络最大流不变的前提下,尽量移除较少被窃听链路或者正常链路,以保证窃听者无法得到完整的网络源信息,而信宿节点能够正常地接收到所有的信息。根据得到的安全网络拓扑构造新的系统传输矩阵,从而获得安全网络编码,达到抵御搭线窃听攻击的目的。仿真实验证实提出的方法能够有效地抵御搭线窃听攻击。     

一种移动网中的匿名组播通信协议*

基于典型的组播路由协议ODMRP,提出了一种移动自组网中的匿名组播路由协议——AODMRP。在AODMRP中,通过采用假名机制和加/解密机制,可以防范数据包窃听、泄密节点攻击和反向路径跟踪等匿名攻击,能够有效地提供组播发送者、接收者以及传输路径相邻节点间通信的匿名性。     

基于编码混淆的匿名通信机制

无线网络的开放性、拓扑动态变化性决定它容易受到多种攻击的威胁,现有的匿名通信模型都无法完全适应链路开放、拓扑动态变化、资源有限的无线网络。提出了一种多级编码混淆的匿名转发机制,该机制通过在各个节点进行内部数据包随机编码,使各个节点出入的数据包对应关系及信息形式发生变化,结合多路径传输方式,提高了匿名通信抗流量分析攻击的能力,同时改善了系统的匿名性。     

AMAODV：匿名组播路由协议

基于典型的组播路由协议MAODV,提出一种基于树的移动自组网匿名组播路由协议AMAODV。在AMAODV协议中,通过采用假名机制和加解密机制,可以防范数据包窃听、泄密节点攻击等匿名攻击,能够有效地提供组播发送者、接收者以及传输路径相邻节点间通信的匿名性。     

基于网络编码的信息流重构匿名通信机制

现有的以PKI为基础的匿名通信机制很难应用于无信任中心的分布式环境下.基于网络编码技术提出了一种新的匿名通信机制NCBACM.NCBACM利用每个编码节点都对转发信息进行随机编码的思想,将匿名路径信息以及数据消息进行分片、编码、混淆后分散在不同的传输路径上进行传输,在无须加/解密变换的情况下进行匿名路径的建立,同样可以...     

无线多跳网络下解码率可控的匿名网络编码

无线网络易于受到外界攻击,现有的匿名通信方案均无法满足资源受限的无线网络,网络编码的自然匿名特性能够较好地解决这一问题,但是其解码率很难控制。LT码的编解码特性可以有效控制可解码率,但是它对于多级传输过程无法适应。结合LT码和网络编码的思想,采用LT码的编解码方式,通过控制各节点编码包的度分布和对系数矩阵的重新构造完成再编码,完成多级匿名通信,使得信宿在解码时解码率接近1－δ。     

抗万能攻击的安全网络编码

提出了一种能够抵抗万能攻击者的安全网络编码算法。在敌人可以窃听所有节点和信道及污染zo个链路的情况下,该算法利用稀疏矩阵对信源信息进行矩阵变换,增强了信息的抗窃听能力,并利用列表译码法在信宿处进行译码,对污染攻击进行检测和排除。理论分析和仿真结果表明,该算法能够在多项式时间内设计完成,能够抵抗窃听和污染等安全性攻击,使得原本的随机网络编码以很高的概率达到弱安全的要求;同时提高了编码速率,减小了存储空间的占用。更重要的是,该算法仅在原随机编码体制的基础上对信源和信宿进行了修改,中间节点保持不变。     

一种网络编码机密性保障机制—C-Coding

为了解决现有网络编码的机密性保障机制不能抵御全局的窃听攻击,并且需要牺牲一定的带宽以实现香农安全的问题,提出了一种机密性保障机制C-Coding以抵御针对网络编码的全局窃听攻击。对随机线性编码的机密性进行了定量分析并运用于C-Coding。理论分析和攻击实验表明该机制可在全局窃听假设下为基于网络编码的传输提供较高的机密性保障。实验结果显示在密钥长度不小于13时,受遗传算法攻击时成功概率几乎为0。使用该机制能较好地保证基于编码的网络传输的安全高效。     

网络编码在窃听网络中的应用

在窃听者窃听能力受限的网络中使用网络编码传输数据时,将网络编码允许中间节点混合收到的数据组这一特点与传统密码学中一次一密的思想相结合,提出了一个基于线性网络编码的有效对抗窃听攻击的安全通信方案.该方案无需秘密信道传榆密钥,同时网络容量的使用率达到n-1/n.而且,当网络编码的系数域足够大时,该保密通信方案使用随机网络编码实现安全通信的概率趋于1.     

一种基于列表译码法的改进的安全网络编码

提出一种基于列表译码法的改进的安全网络编码算法,该算法仅在原随机编码体制的基础上对信源和信宿进行了改变,中间节点保持不变.在信源处,该算法向信源信息中加入少量冗余,并利用稀疏矩阵对其进行矩阵变换,从而增强信息在传输过程中的抗窃听能力;在信宿处,用列表译码法对收到的信息进行译码,从而对污染攻击进行检测和排除.信源和信宿之间不需要任何秘密信道.理论分析和仿真结果表明,该算法能够在多项式时间内设计完成,能够抵抗强窃听和污染等安全性攻击,使得原本的随机网络编码以很高的概率达到信息论安全的要求;该算法提高了编码速率,减小了存储空间的占用.     

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。     

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.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

基于QTE的蒙古文显示机制研究与实现

蒙古语言是中国蒙古族使用的通用语言,由于蒙古文区别于其他文字的书写方式和其自身变形机制等特点,在很多通用的文字处理引擎中都不被支持。在嵌入式产品开发与应用领域中Linux加QTE已经成为流行方式。该文给出了一种在QTE环境上实现基于标准Unicode的蒙古文点阵显示和变形算法, 并自定义了支持蒙古文的QTE组件,扩展了QTE功能,为在Linux加QTE方式的嵌入式体系结构中处理蒙古文提供了一种解决方法。