基于区域的无线传感器网络混合密钥管理方案

针对现有密钥管理方案连通性不高、计算开销和通信消耗较大等问题,提出一种基于区域的无线传感器网络(WSN)混合密钥管理方案。该方案将部署区域划分为多个正方形区域,区域由成员节点和头节点组成。同一区域中任意两个节点都能够根据预分配的密钥空间信息建立起会话密钥,而不同区域间只能通过头节点进行通信。计算多元非对称二次型多项式的特征值和特征向量,然后得到正交化信息,头节点通过交换该信息实现身份认证并生成与邻居节点之间的会话密钥。性能分析表明,与现有的密钥管理方案相比,该方案具有完全连通性,在通信开销、存储消耗、安全性等方面均有较大改进。     

基于区域的无线传感器网络混合密钥管理方案

针对现有密钥管理方案连通性不高、计算开销和通信消耗较大等问题,提出一种基于区域的无线传感器网络(WSN)混合密钥管理方案。该方案将部署区域划分为多个正方形区域,区域由成员节点和头节点组成。同一区域中任意两个节点都能够根据预分配的密钥空间信息建立起会话密钥,而不同区域间只能通过头节点进行通信。计算多元非对称二次型多项式的特征值和特征向量,然后得到正交化信息,头节点通过交换该信息实现身份认证并生成与邻居节点之间的会话密钥。性能分析表明,与现有的密钥管理方案相比,该方案具有完全连通性,在通信开销、存储消耗、安全性等方面均有较大改进。     

基于区域划分的WSN混沌密钥管理方案

针对经典随机密钥预分配方案在网络安全性、连通性和能耗方面存在的不足,提出一种基于区域划分的无线传感器网络(WSN)混沌密钥管理方案。使用划分网络区域的方法进行密钥更新,以减少节点存储开销,利用混沌的初值敏感性和遍历性增强通信的安全性。仿真结果表明,该方案可以在提高WSN连通性和安全性的同时,较大地降低节点存储和通信能耗。     

无线传感器网络密钥种子管理和分配模型及应用

随机密钥种子预分配方案是实现安全的无线传感器网络应用的首选方案,该方案在无线传感器网络节点布置之前建立和分配某种密钥种子信息,在网络节点布置之后利用密钥种子信息建立或发现节点之间安全的通信链路.根据传感器网络的通信保密和节点认证需求,提出了通用密钥种子管理和分配模型(KSMA).该模型可用于预分配方案的安全分析,描述了预分配方案的5个安全属性.在KSMA模型中,基于单向累加器,定义了一类新的密钥种子结构,提出了新的密钥种子预分配方案和节点秘密共享发现协议,并在UC(universally composable)安全框架中对新的秘密共享发现协议进行了可证明安全分析.在新方案中说明了如何设定密钥池参数和节点密钥链参数的方法,该方法不仅保证了高概率的安全链路建立,而且可以通过节点身份证人确认机制实现节点之间身份认证,有效地防御传感器网络Sybil攻击.通过与其他方案的分析对比,新方案改善了网络安全弹性、综合性能良好.     

异构传感器网络中对密钥建立方案

针对现有异构传感器网络(HSN)密钥预分配方案的安全问题,提出一种基于部署知识和密钥链技术的对密钥建立方案.将部署区域划分成多个单元,整个HSN网络划分成簇.在部署区域中,相邻节点使用预分配密钥信息建立共享密钥.在节点部署完成后,当两相邻节点不能建立共享密钥时,通过其他高能节点为其分配共享密钥.理论分析和模拟结果表明,...     

基于网格部署模型的WSN密钥分配方案

针对现有密钥预分配方案中网络连通性差、存储开销大、节点抗攻击能力不强等问题,提出一种基于网格部署模型的无线传感器网络密钥分配方案。该方案将部署区域划分为相互不重叠的六边形网格,为每个网格分配多个不同的密钥空间,且使任意相邻的网格之间仅共享一个密钥空间。根据节点的部署信息和已知的区域信息为其分配密钥信息,从存储开销、网络连通性和安全性方面对方案进行性能分析。实验结果表明,与已有密钥分配方案相比,该方案的网络连通率为1,不仅能降低节点内存需求,而且增强了无线传感器网络中节点抗随机攻击和区域攻击的能力。     

基于区域的无线传感器网络密钥管理

要密钥分配是无线传感器网络中极具挑战性的安全问题之一．目前提出的解决方法是采用密钥预分配策略,给每个节点分配多个密钥,如Eschenauer和Gligor提出的随机密钥预分配方案（R—KPS）．随机密钥预分配方案没有利用节点的部署和位置信息,在许多应用场合中,部署和位置信息能被用于改善网络性能．在R—KPS中,每个节点有可能成为其它任何节点的邻居,所以节点必须从同一密钥池中选取密钥．如果能把网络划分为多个区域,则同一区域内和相邻区域间的节点更有可能成为邻居．文章提出一种利用已知区域信息的密钥预分配方案,相比随机密钥预分配方案,能提高网络的连通性,减小节点所需存储空间,并能增强网络抗攻击能力．最后利用上述区域信息提出一种不借助定位设备的节点定位算法,此算法实现简单,适用于定位精度要求不高的场合．     

传感器网络多密钥空间分层密钥预分配方案

提出一种传感器网络多密钥空间分层密钥预分配方案。该方案把部署区域划分为正六边形网格,将节点分成不同的簇,密钥空间划分为与簇相对应的子集;簇头节点之间采用多密钥空间随机预分配方案进行共享密钥发现,簇头节点与普通节点间则采用单项散列计算的方式计算共享密钥。性能分析和仿真结果表明,该方案在连通率及抗捕获攻击方面有较好的性能改善,通信和存储开销预算较合理。     

一种基于六边形部署模型的面向传感器网络的随机密钥预分配方案

针对基本随机密钥预分配方案和基于部署信息的密钥管理方案中存在的不足,提出了一种基于六边形部署模型的面向传感器网络的随机密钥预分配方案。该方案更充分地利用了六边形部署模型的特点,通过将部署区域划分为六边形网格,并将传感器节点按其标志号进行分类,然后根据节点期望部署的网格位置和其节点类别进行相应的密钥预分配,从而有效改善了网络的安全性能。分析和仿真表明,在相同的存储开销下,本方案具有更高的安全连通率和更强的抗节点捕获攻击能力。     

WSN中基于多边形分组部署模型的密钥管理方案

无线传感器网络(WSN)在高连通度的条件下保证网络安全至关重要。提出一种基于多边形分组部署模型的密钥管理方案,该方案把监测区域划分成多个大小相等的n边形,对各n边形分组的性能进行比较,并提出基于最优模型树状结构的建立及密钥分配方案。理论分析与实验结果表明,该方案适用于大规模的WSN,在减少节点密钥存储量的同时,提高了网络的连通性。     

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。     

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。