IKE协议主模式认证机制的分析与改进

文章深入分析研究了IKE协议主模式认证的交换过程及认证机理,针对基于预共享密钥认证方式中存在的仅适用于固定IP地址和不能保护通信双方身份信息,以及基于数字签名认证方式中存在的不能保护协议发起方身份信息的缺陷,分别给出了相应的改进方案,并与以往改进方案进行了分析比较。     

基于改进语义SVO逻辑的二维认证协议分析

一种基于二维几何距离的实体认证协议无需在非安全信道当中传送密钥,使得认证的过程更加安全与便捷,然而该协议的正确性与安全性并未得到严格论证。考虑该实体认证协议的特点,采用改进语义的SVO逻辑对其进行合理性描述,并对其运行过程进行形式化的具体分析,发现该协议在认证过程中存在着双方认证不确定的缺陷。针对此缺陷提出了一种修正方案,以确保认证协议的正确性,并且通过改进语义SVO逻辑的形式化分析证明了该改进认证协议的安全性。     

一种改进的直接匿名认证方案

介绍可信计算中直接匿名认证(DAA)方案的研究与发展,针对现有解决方案中由于EK密钥泄露而造成的Rudolph攻击,提出了一种改进的直接匿名认证方案。与原方案相比,改进的方案在Join阶段提出了一种新的密钥交换协议,在实现DAA证书发布者和示证者双向身份认证的同时,将EK证书的认证过程和DAA证书的签发过程分离,从而避免了Rudolph攻击的出现。通过利用CK模型对提出的密钥交换协议进行分析,表明改进的方案中的密钥交换协议达到SK安全等级;该方案保证了用户可控的匿名性,并且可信第三方不会成为方案瓶颈。     

双主体认证协议抵御DoS攻击的安全方案

认证协议存在的一定的拒绝服务(DoS)攻击隐患。该文在cookie机制和工作量证明方法思想的基础上,采用弱认证和强认证相结合的方法,提出了双主体认证协议抵御DoS攻击的安全方案,给出了方案的实现细节和部分实验数据,分析了该方案的安全性。应用该方案对Lowe的NSPK协议进行改进,并分析了改进后协议的性能。     

串空间模型中认证性测试方法的缺陷

指出了串空间模型中认证性测试方法存在的不足：1．分析认证性的过程中未考虑同一协议主体同时以不同身份参与协议运行的情况;2．分析认证性的过程中未考虑发生多轮协议同时运行的情况;3．认证性测试方法不能分析类型错误攻击。通过实例-——Needham-Schroeder协议分析了认证性测试方法存在不足的原因,并提出了改进方案。     

基于DESX的Kerberos协议的分析与改进

Kerberos协议是一种基于可信第三方的身份认证协议,针对Kerberos协议具有口令猜测攻击、重放攻击等缺陷,提出一种基于DESX算法和SHA函数的Kerberos协议改进方案,通过分析比较,改进协议不但摒弃了原Kerberos协议存在的缺陷,且以相对较小的开销使Kerberos协议认证过程更安全可靠。     

认证协议中数据同步的分析

认证双方数据的同步是认证协议以及认证密钥交换协议的基本要求,但是在协议设计过程中难以把握且经常被忽视。对近年来可证明安全的一个RFID认证协议和一个RFID认证密钥交换协议以及可证明安全的一个移动卫星通信系统认证密钥交换协议进行了仔细分析,分别发现了针对这些协议的数据同步攻击,这些攻击破坏了协议的可用性。最后分别给出了改进方案,以克服存在的安全隐患。     

浅析第三代移动通信的认证与密钥分配

详细阐述了3G系统的认证与密钥分配协议的过程,分析了协议中可能存在的安全缺陷,提出了一个简洁有效的改进方案。     

突破认证测试方法的局限性

认证测试是一种用于证明安全协议认证属性的新方法,该方法能够简化协议认证属性的证明过程,但其局限性是无法应用于认证测试元素被多重加密的情况.指出Perrig和Song提出的认证测试改进方案在多个方面所存在的问题.在此基础上提出新的改进方案,并进行了形式化证明.新的认证测试定理突破了认证测试元素在整个协议消息中不能被加密的限制,扩展了认证测试理论的应用范围.     

S/Key协议的分析与改进

本文分析了S/Key协议的安全性,指出了其中存在的安全漏洞.针对其不能抵抗冒充攻击和协议破坏攻击的缺陷,通过在认证过程中加入随机数,对S/Key协议进行了改进,并分析了改进方案的安全性.     

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。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.