基于混沌加密的可同步更新RFID双向认证协议

针对日益突出的RFID系统安全隐私问题,提出了一个基于混沌序列的RFID双向认证协议。利用混沌对初始值的敏感性生成混沌序列,对密钥进行加密。该协议引入标签密钥动态更新机制,并设计了自同步解决方案,实现了对标签的二次认证。采用BAN逻辑对其安全性进行证明,并与已有的协议进行安全性分析和性能比较。其分析结果表明,该协议降低了标签成本,减少了标签和后端数据库的计算量,提高了后端数据库的检索效率。不仅有效地解决了RFID系统的隐私保护及安全问题,同时也提高了RFID协议认证的执行效率,更适合低成本的RF1D系统。     

适用于供应链的RFID读写器-标签双向认证协议

基于批量处理的特性,提出一个适用于供应链的可扩展的读写器-标签双向认证协议.在该协议中,后端数据库识别一个标签只需运行3次哈希函数和O(logn)次比较大小的运算,标签的计算量和已有的不可扩展的协议相当.提出的协议显著提高了射频识别RFID(Radio Frequency Identification)供应链管理系统的效率,并且满足其安全需求.     

基于hash运算的RFID认证协议分析和改进*

针对已有基于hash运算的RFID认证协议所面临的安全问题,提出了一种新的适合低成本RFID的双向认证协议,并与已有的协议进行安全性分析和性能比较。结果表明该协议仅使用hash函数和异或操作,就达到机密性、完整性和防追踪性的安全目标,并运用时间戳作为标签查询标志,提高认证过程的执行性能。因此该协议与先前工作相比,更适合低成本的RFID系统。     

一种更具实用性的移动RFID认证协议

针对Doss协议的不足,提出了一种改进的轻量级移动RFID认证协议。首先使用二次剩余混合随机数加密的方法提高后台服务器识别速度;在阅读器端添加时间戳生成器,抵御阅读器冒充及重放攻击。新协议标签端只采用成本较低的伪随机数生成、模平方以及异或运算,遵循了EPC C1G2标准,且实现了移动RFID环境下的安全认证。理论分析及实验显示了新协议提高了Doss协议后台识别速度,并满足标签和阅读器的匿名性、阅读器隐私、标签前向隐私等安全需求,更有效抵抗已有的各种攻击：重放、冒充、去同步化攻击等。与同类RFID认证协议相比,实用性更佳。     

供应链环境下UC安全的RFID所有权转移协议*

针对供应链环境下无线射频识别(RFID)标签流动所涉及的节点隐私和供应链可见性管理问题,定义了供应链环境下RFID标签所有权转移的安全需求,提出了通用可组合安全模型,并基于所提出的RFID认证协议,设计了一个能实现该模型的RFID标签所有权转移协议。安全性证明和效率分析表明该协议通过利用授权机制和哈希函数的单向性,很好地解决了可见性和不可追踪性问题,采用索引机制和标签端轻量级的计算方式提高了执行效率。与同类方案相比,该协议降低了标签端的计算量且安全性更高。     

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。     

移动RFID高效率认证协议设计

移动RFID的无线通信与移动应用给认证提出更高要求,针对当前移动RFID认证协议安全性不强及认证效率不高问题,提出移动RFID高效率认证协议。协议通过执行算术运算、按位运算及数据排列组合,保证了信息传输安全;通过后台数据库和移动阅读器对随机数的递进式验证,标签对随机数的捆绑式验证,有效防范敌手攻击。由于通信实体均执行轻量级运算,大幅提高系统计算性能;通信实体的递进式验证实现了对标签数据的初步筛选,缩短无效认证时间,提高认证效率。利用GNY形式化语言对协议正确性进行了证明。理论分析表明,该协议可抵御多种类型攻击。仿真结果显示,与同类移动RFID认证协议相比,该协议认证效率高,应用价值好。     

一种超轻量级RFID双向认证协议

开放的无线通信环境,尤其是阅读器和标签间的无线信道,使得无线射频识别(RFID)系统的安全和隐私问题逐渐成为值得关注的焦点,因此设计抗各种恶意攻击和安全威胁的超轻量级RFID 认证协议是非常必要的。针对低代价标签提出了一种新的超轻量级RFID双向认证协议,该协议避免了已有RFID认证协议存在的安全隐患。安全分析表明新协议具有较强的安全和隐私属性,并且能够抵抗各种可能的恶意攻击。根据低代价RFID标签资源受限的需求,新协议仅需要在标签上执行两种简单的比特位操作,与其他超轻量级RFID认证协议相比具有更好的性能优势。     

基于Hash链的RFID认证协议

为了提高大规模RFID系统的认证效率,通过分析现有RFID系统的认证效率和安全性,提出了一套基于Hash函数的改进协议。向RFID读写器加入过滤规则,能够有效过滤恶意和无效的认证请求;对标签的访问计数器值的分层化、更新和重置,可以有效提高后端数据库检索数据的命中率。通过分析和测试,该协议能够有效抵御假冒攻击、重传攻击等不安全问题,有效提高RFID认证的效率,降低认证服务器计算负荷。     

基于伪随机函数的RFID双向认证协议

针对在物联网应用中,现有的RFID安全认证协议存在安全缺陷和认证效率低等问题,提出了一种改进的基于PRF的RFID双向认证协议,通过对读写器产生的随机数进行加密的方法,来解决原协议存在的安全隐患问题;采用随机数使标签保持信息的新鲜性。通过和已有的此类安全认证协议进行安全性比较,结果表明改进的协议不仅具有防跟踪、抗暴力破解、防重放攻击等特点,而且保证了标签没有大幅增加计算量。     

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.