无线传感器网络中基于代理的D-S数据融合

提出了一种无线传感器网络中基于移动代理带证据权的D S融合算法。引入证据权对证据进行修正以降低冲突数据对融合结果的影响。采用三级D S组合规则进行融合决策：节点级融合计算单个节点时间域融合检测概率;簇内级融合计算簇内节点间空间域融合检测概率获取局部决策结果;簇间级融合计算簇间的融合检测概率获取最终的全局决策结果。仿真结果表明,本算法能以较小的能耗代价获取准确的融合结果并有效降低冲突数据对融合结果的影响。     

基于信誉度集对分析的WSN安全数据融合

由于无线传感器网络存在资源约束问题,为了有效地减少无线传感器网络中的数据传输量以降低网络的总能耗,同时确保对感知数据进行融合操作的安全性,提出了一种基于传感器节点信誉度集对分析的安全数据融合方法.在节点分簇阶段,利用基于密度函数的减法聚类方法进行分簇,既获得了较快的分簇速度,又保证了簇头节点地理位置的合理分布,使得分簇规模更加符合节点的实际布设情况.在数据传输阶段,将簇头节点选择下一跳数据转发节点建模为多属性决策过程,综合考虑备选转发节点的信誉度、能量等属性信息,从中选择综合评价最优的簇头节点转发融合数据,不仅使网络中的数据流量分布更加均衡而且保证了数据的安全性.仿真结果表明,提出的数据融合算法在融合精度、安全性及簇头节点能耗方面与同类的LEACH算法和BTSR算法相比具有明显的优势.     

基于非均匀分簇和信息熵的无线传感网络路由算法

针对无线传感网络分簇算法中能量分布不均衡导致的“热区”问题,提出一种基于非均匀分簇和信息熵的路由算法。在簇头选举和竞争半径计算过程中综合考虑节点能量、节点密度和节点距基站距离,均衡簇头能耗以延长生存时间。采用簇间单跳多跳混合通信的路由规则,减少簇间通信能耗。对节点信息熵进行数据融合,引入融合权重系数减小数据融合的不确定性,提高数据融合效率。仿真结果表明,与LEACH、EEUC和EBUCA相比,该算法能够有效均衡网络能耗,延长网络生命周期。     

WSN中一种负载均衡的动态非均匀分簇方案

无线传感器网络(WSN)是由资源受限的传感器节点构成,节点能耗对网络的性能有着重要影响,对网络进行分簇可以有效地控制节点整体能耗。针对网络实际运行时节点状态和事件位置动态变化等特点,提出了一种负载均衡的动态非均匀分簇方案。方案主体思路是:首先网络利用O-LEACH算法自组织地进行非均匀分簇,接着动态地从簇头中选举出一定数量的决策节点用于网络的数据汇聚,并根据事件发生位置和节点状态变换而动态更改决策节点角色。仿真结果表明,与CAPNet方案相比,该方案均衡了网络能耗,提高了传输效率,延长了网络生命周期。     

能耗均衡的无线传感器网络两级路由协议*

传感器网络分簇路由协议研究的一个关键问题是如何最优化组簇,既能有效降低簇内节点能耗,又能均衡整个网络能耗。为此,提出一种能耗均衡的网络两级分层分簇路由协议。协议底层应用PSO算法实现网络节点最优化分簇;上层选择总簇头节点负责收集、融合簇头数据并发送至基站。仿真结果表明,本协议能有效降低节点死亡速度,延长网络生存周期。     

一种基于分簇技术的数据融合算法

针对无线传感器网络节点能耗的限制以及通信数据的隐私问题,提出一种基于分簇技术的数据融合算法（Data Fusion Algorithm based on Clustering Technology, DFACT）。算法通过分簇技术解决通信数据的时延,簇内利用算法选择合适簇头,并构造数据融合树结构进行数据融合,减少数据通信量,保护数据隐私;簇间采用基于移动代理模型选择最佳路径提高通信效率。实验结果表明,DFACT算法可以有效地降低大规模无线传感器网络节点耗能,提高数据的安全性,延长网络生命周期。     

基于多属性关联决策的WSN故障检测方法

针对无线传感器网络中节点单一属性表征能力差且阈值范围难以确定的问题,提出一种基于多属性关联决策的分布式故障检测方法。以非均匀分簇网络结构为基础,融合距离因子与节点间相关分析结果估计簇头置信区间。在可靠簇头条件下,通过显著性检验方法对簇内成员节点状态进行反馈式决策,并基于相对熵理论定义多属性关联度,用于分析异常数据来源。实验结果表明,面对不同故障类型,该方法均能有效提高网络节点的故障检测精度并确定异常来源,在节约能耗的基础上,确保网络稳定运行。     

基于蜂窝网络结构的数据融合算法

针对无线传感网中节点能耗同数据精确度之间不均衡的问题,提出一种能够基于蜂窝网络结构的数据融合算法（DFACN）。在基于蜂窝网络的分簇结构中,首先筛选最小能耗的簇头;之后通过数据精确度和节点能耗的计算判断融合因子的大小,动态选取参与融合的簇内节点数;最后簇头完成数据的融合处理。在OPNET仿真环境下,与EECDA和IDDOA算法进行实验对比,DFACN算法的数据精确度分别提高了2.6%和4.7%,节点能耗分别降低了2.7%与3.4%。结果表明,DFACN算法在降低能耗的同时,有效地提高了数据的融合精确度,并且延长了网络的生命周期。     

基于环的能耗均衡分簇路由算法

针对无线传感器网络分簇路由算法中节点能耗不均的问题,提出了一种基于环的能耗均衡分簇路由算法。算法对监测区域作基于环的分簇,在靠近基站的“热区”内划定数据汇聚区,汇聚区内的节点不分簇,节省分簇及簇内通信能耗;对汇聚区外其他环的簇个数进行优化以均衡能耗。提出新的最优路径搜索策略,寻找整体最优路径,进一步减少网络能耗。仿真结果表明,提出的算法在能耗均衡性上比改进的LEACH路由协议(LEACH-R)和一种能量高效的非均匀分簇算法(EUCA)更优;以50%节点死亡作为网络生命周期,网络寿命分别提高约30.9%和11.9%,有效延长了网络生命周期。     

基于博弈理论的无线传感器网络数据融合算法

数据融合是无线传感器网络研究热点之一。为了减少传感器节点间的数据通信量,有效地节省传感器节点能耗,延长无线传感器网络的寿命,提高数据融合的准确性,减少网络时延,提出一种基于博弈理论的无线传感器网络数据融合算法。该方法将所有网络节点根据能耗最优进行分簇,簇头与监控中心通过博弈来自适应地选择不同融合因子的融合算法,使整个网络的总效益最大。实验仿真表明,在丢包率不同时,自适应融合算法可以得到最佳的融合因子,有效实现了时延和精确性的均衡。该方法为无线传感器网络中各个指标的折中提供了参考方向。     

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.