异构无线传感器网络的密钥管理方案

本文针对无线传感器网络能量和计算能力等局限性问题,提出了一种基于分簇结构的无线传感器网络密钥管理方案。该方案采用椭圆曲线的双线性对加密技术对节点的身份进行认证,通过验证节点的合法性来抵抗非法节点的攻击。     

一种改进的无线传感器网络密钥管理方案

在无线传感器网络中,针对已有动态更新密钥管理方案的无身份认证、可扩展性差等问题,提出一种实用的无线传感器网络密钥管理方案。采用增加身份认证模块的方法,设计可行的新节点加入机制。分析结果表明,与原方案及同类密钥管理方案相比,该方案在保持安全高效的同时,具有更好的可扩展性和网络连通性。     

基于 IBC的无线传感器网络层簇式密钥管理方案*

密钥管理是无线传感器网络中关键安全技术之一。无线传感器网络的密钥管理由于布置位置、计算量有限、存储能力有限,使得设计面临许多挑战。在分析无线传感器网络安全需求的基础上,针对无线传感器网络密钥管理问题,运用层簇式网络结构,通过身份加密方式,进行节点合法性认证,完成基站与簇头,簇头与节点之间的密钥,保证无线传感器网络安全通信。通过安全性分析和效能分析,该密钥管理方案较好的满足无线传感器网络的安全需求,降低通信开销,有效地解决密钥管理的问题。     

一种新的基于双线性配对的无线传感网络密钥协商方案

针对无线传感器网络密钥协商中安全性不足的问题,提出了一种适合无线传感器网络的密钥协商方案KASBP。该方案首先运用基于双线性配对的运算预置网络系统参数并通过计算获得节点的相关参数;然后节点向邻居节点广播,并利用Diffie-Hellman密钥交换技术,使节点间能够共享密钥。理论分析结果表明,KASBP方案的执行效率不仅优先于LZC和Shim-Woo的密钥协议方案,同时也符合已知密钥安全完美前向安全密钥泄露安全未知共享密钥安全密钥支配安全等安全需求。     

一个新的基于身份的无线传感器网络密钥协商方案

无线信道具有开放性,节点间建立配对密钥是无线传感器网络安全通信的基础。在大部分基于身份加密(Identity-Based Encryption, IBE)的传感器网络密钥协商方案中,使用双线对运算建立配对密钥,能耗高且耗时长。基于BNN-IBS身份签名提出了一个新的无线传感器网络密钥协商方案,节点通过Diffie-Hellman协议建立配对密钥,所需的密钥参数通过广播获得。与基于IBE的传感器网络密钥协商方案(IBE-based Key Agreement Scheme, IBEKAS)进行量化比较,结果表明本方案不仅提供了与IBEKAS同层次的安全性与可扩展性,且在能耗与时耗方面具有较明显的优势。     

基于TePA的无线传感器网络安全方案

针对无线传感器网络的安全需求, 结合TePA技术提出了一种基于TePA的无线传感器网络安全方案。该方案简化了TePA技术的身份认证分组和分组字段, 解决了无线传感器网络在传感器节点接入和密钥协商的问题。采用改进的BSW逻辑验证了协议, 并从协议安全性和网络性能方面分析了方案, 结果表明方案能抵抗中间人攻击和重放攻击, 并适合无线传感器网络。     

基于秘密共享的无线传感器网络广播密钥分发协议

在无线传感器网络中,能量消耗主要集中在节点之间的通信上,节点计算所消耗的能量远小于通信所消耗的能量。由于无线传感器网络的"一对多"和"多对一"通信模式,广播是节约能量的主要通信方式。为了保证广播实体和消息的合法性和保密性,必须首先解决无线传感器网络广播密钥安全分发问题。本文在充分考虑无线传感器网络自身特点的基础上,基于Shamir的门限秘密共享方案,提出了椭圆曲线双线性对上的无线传感器网络广播密钥分发协议,并对其进行安全性和性能分析。分析发现,该协议不仅满足安全性要求,同时,能够适合无线传感器网络的特殊应用要求。     

基于对的无线Ad hoc网络可追踪邻居匿名认证方案

为解决传统无线Ad hoc网络邻居匿名认证方案容侵性不佳以及难以锁定恶意节点身份的问题,提出一种基于双线性对的无线Ad hoc网络可追踪邻居匿名认证方案。采用基于身份的公钥系统,节点随机选择私钥空间中的数作为临时私钥,与身份映射空间的节点公钥以及一个公开的生成元模相乘得到临时公钥,利用双线性映射的性质协商会话密钥并实现匿名认证。通过在随机预言机模型下的形式化分析,表明本方案在BCDH问题难解的假设下可对抗攻击者的伪装行为,同时利用认证过程中交互的临时公钥可有效锁定恶意节点真实身份。     

基于圆锥曲线密码的WSNs密钥管理方案

为有效解决资源有限的无线传感器网络密钥管理问题,给出了一种基于圆锥曲线无线传感器网络密钥管理方案。通过引入证书服务,实现了密钥的分配和新加入节点密钥的生成、更新、撤销等过程,并从方案的安全性、可扩展性和效能方面进行性能分析。实验分析结果表明:与经典密钥管理方案相比,所给方案能够有效减少密钥存储空间,并且具有较强可扩展性和抵抗网络攻击的能力。     

无线传感网动态可认证群组密钥交换协议

无线传感器网络中节点电池电量有限、节点计算能力及存储能力受限,使得现有的大部分群组密钥交换技术不适用于无线传感器网络。针对该问题,提出一种动态的可认证群组密钥交换协议。采用双线性映射技术实现无线传感器网络中节点之间的群组密钥交换。该协议具有可认证性,避免群组密钥交换过程中遭到欺骗攻击及中间人攻击;具有动态性,适用于无线传感器网络节点动态部署;在双线性计算Diffie-Hellman(bilinear computation Diffie-Hellman,BCDH)困难性假设下是可证安全的。分析结果表明,该协议具有较高的安全性和较好的性能。     

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.