一种基于双PUF的RFID认证协议

针对Liang等人提出的基于双物理不可克隆函数(physical uncloneable function, PUF)的无线射频识别(radio frequency identification, RFID)认证协议进行分析发现其存在安全隐患,不能抵抗重放攻击、去同步攻击、标签伪造等恶意攻击.为解决由于恶意攻击者对RFID系统所造成的安全隐患问题,提出一种基于双PUF的RFID认证协议DPRAP.在伪随机数发生器种子生成阶段,不直接在非安全信道上传输种子的通信值,通过多次的Hash与异或运算对种子的值进行加密隐藏,保证协商种子的机密性;在标签与服务器的伪随机数发生器种子协商过程中,使用一个时间阈值,防止攻击者恶意阻塞通信信道引发去同步攻击,确保服务器与标签端的伪随机数发生器种子的同步性;在认证阶段,在认证信息中增加使用标签的身份标识IDS来对标签的合法性进行验证,防止标签假冒攻击.通过使用BAN逻辑和Vaudenay模型对DPRAP协议进行形式化分析和验证,证明DPRAP协议满足不可追踪性,能够抵抗去同步攻击、标签假冒攻击等攻击手段,结果表明DPRAP协议具有更强的安全隐私性和更好的实用性.     

基于随机数同步更新的RFID安全协议

针对无线射频识别(RFID)应用的安全问题,提出一种基于随机数同步更新的RFID安全协议。利用RFID后端系统生成的随机数实现标签认证,每次认证完成后对标签和随机数做同步更新。从理论上分析协议的执行性能和安全性,并利用BAN逻辑对协议的安全性进行形式化证明。结果表明,该协议能够实现标签和阅读器之间的相互认证,同时可抵抗重放、位置跟踪、流量分析、伪装、拒绝服务、非法读取等攻击。在实现上该协议仅使用哈希和异或运算,降低了标签的计算复杂性,适合低成本标签应用。     

基于读写器和双重ID验证的RFID安全协议

针对海量标签应用导致RFID系统成本提高的缺点,本文分析现有RFID安全协议的特点及局限性,提出重点关注功能强大的读写器,并提出一种新的基于读写器和双重ID验证的RFID安全协议。读写器对标签的ID(伪ID)进行第一次验证,然后该伪ID与替换表配合,形成一个新的真实ID,读写器进行第二次验证。整个通信过程采用Hash加密和随机数发生器来提高系统安全性。分析结果表明,该协议可以明显降低RFID系统的成本,防止网络攻击,适合于大规模使用标签的RFID系统中。     

基于RBAC的RFID安全认证协议

对于低成本RFID系统,其安全隐私问题一直是研究的热点。为了保护用户的隐私安全,现有的RFID安全认证协议主要采用Hash函数、传统加密算法等来保证标签信息的安全,虽然在一定程度上保证了信息的安全,然而这些协议却忽略了对非授权标签信息的保护。为了弥补以上缺陷和不足,提出了一种基于角色访问控制RBAC的RFID安全认证协议。通过引入RBAC机制,能够有效地确保非授权标签信息的安全性,并且可以抵抗重传攻击、内部阅读器攻击等攻击。同时,利用部分ID、位运算等方法降低系统对标签的硬件要求,更适合低成本RFID系统。     

基于不可追踪模型的轻量级RFID认证协议

在Ha等提出的基于Hash函数的低成本RFID认证协议中, 敌手捕获 标签和读卡器之间传送的信息后,就可以实现跟踪攻击。在分析Ha等提出的低成本RFID认证协议的基础上,设计出了 效率更高的追踪攻击算法。Ha等提出的低成本RFID认证协议易于遭受追踪攻击,敌手可以从低位到高位,逐个比特位地猜测出合法的标签密钥的比特位,针对这一缺点提出了可以抵抗追踪攻击的改进协议,并用不可追踪模型形式化证明了该协议不可追踪的鲁棒性。     

基于Hash链的非对称密钥RFID认证协议

安全认证协议是解决RFID系统安全威胁的有效手段,针对一些基于Hash链的认证协议存在的安全和效率问题,提出了一种基于Hash链和非对称密钥的改进协议。将非对称密钥应用到标签和后台数据库之间的数据加密可以提高系统的安全性;后台数据库用解密后的ID值建立动态索引,提高了后台数据库检索效率。与现有协议进行对比分析,结果表明该协议可以抵抗常见攻击,能够有效提高后台数据库的检索效率和标签认证效率。     

基于Hash函数的RFID安全认证协议研究

无线传输、信号广播、资源受限等特点使RFID技术存在潜在安全隐患.在对RFID技术所面临的安全问题进行了详细地描述和分析后,提出了认证识别的单一会话模式和连续会话模式的概念,基于Hash函数设计了一个介于RFID标签和后端服务器之间的安全认证协议HSAP,以解决假冒攻击、重传攻击、追踪、去同步化等安全问题,并基于GNY逻辑给出了形式化的证明.由于在RFID标签中仅仅使用了Hash函数和或操作,因此HSAP协议跟先前的工作相比更适合于低成本RFID系统.     

基于Hash链的RFID改进协议

由于RFID技术的特殊性和局限性带来了很多安全问题,针对这些安全问题,本文提出了一种Hash链的改进认证协议,以解决假冒攻击、重传攻击、跟踪、前向安全性等安全问题,并基于BAN逻辑给出了形式化的分析,说明改进的协议在BAN逻辑分析下是安全的。由于在RFID标签中仅使用了Hash函数,因此改进的协议更适合于低成本的RFID系统。     

能抵抗拒绝服务攻击且高效的RFID安全认证协议

针对现有的RFID认证协议所面临的安全隐私保护问题,利用Hash函数加密的方法,提出了一种能抵抗拒绝服务攻击且高效的RFID安全认证协议。通过在阅读器上进行随机数的比较与识别,从而使该协议可抵抗拒绝服务攻击,并且在后台数据库中存储标签标识符的两种状态,以便实现电子标签与后台数据库的数据同步。从理论上分析了协议的性能和安全性,并利用BAN逻辑对协议的安全性进行了形式化证明。分析结果表明,该协议能够有效地实现阅读器和电子标签之间的相互认证,能有效地抵抗拒绝服务攻击且与其他协议比较,整个RFID系统的计算量减小,适用于大规模使用标签的RFID系统。     

EPC编码标签的RFID系统密钥无线生成

针对目前RFID系统的认证协议都是在事先设置好的共享密钥值基础上的,敌手可以通过一些手段获取密钥而对后续的认证造成安全威胁,提出了一种基于EPC编码标签的RFID系统密钥无线生成协议。将部分EPC加密进行通信,防止秘密信息泄露;引入标签与阅读器的安全模型,提高通信的安全性;阅读器随机数保持通信过程的新鲜性;仅采用异或运算降低标签成本与计算量。通过GNY逻辑对协议进行形式化证明,安全分析和性能分析表明,该协议符合安全模型并能够抵抗主动攻击和被动攻击,具有安全性高、低成本的特点。     

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.