一种基于聚合度模型的WSNs双簇头分簇路由协议

在无线传感器网络（WSNs）中能量负载不均衡问题,影响了网络的生命周期。提出一种基于聚合度模型的WSNs双簇头分簇路由协议（DCHP）,DCHP协议将节点聚合度与剩余能量作为考虑因素引入阈值计算,从而使高剩余能量且聚合度高的节点优先选为第一簇头。在此基础上,根据簇内节点能量选出第二簇头,完成簇间多跳路由转发数据。仿真实验表明：DCHP协议能更好平衡网络能量负载问题,延长网络生命周期。     

基于遗传模拟退火算法的无线传感器网路由协议

在无线传感器网络中(WSNs)中,由于节点能量有限,为了延长整个网络的生存周期,提出一种基于遗传模拟退火算法的无线传感器网络路由协议.利用模拟退火(SA)算法具有较强的局部搜索能力并能以稳定的速度收敛,克服遗传算法(GA)局部搜索能力差并容易早熟收敛等缺点.该路由协议在簇头节点选举时充分考虑了节点的剩余能量,并根据网络中数据转发能量耗损和延迟时间建立个体适应度函数,采用遗传模拟退火算法找到簇头节点到基站的最优路径.仿真结果表明:与其他协议比较,该方法不仅可以均衡各个节点的剩余能量,还可以有效延长整个网络生存周期和提高网络的数据传输能力.     

基于差分算法的无线传感器网络路由分簇协议

针对异构无线传感器网络分簇路由协议存在节点能耗不均衡问题,提出一种基于差分进化算法的路由协议及基于节点能耗的分簇协议。该协议首先以最大化网络中簇头节点的最小生存周期为目标,建立函数优化模型,并采用差分进化算法对其进行优化,从而延长网络整体的生存周期;然后根据节点通信列表中的簇头数目进行分簇,将节点分配给能耗因子较低的簇头,以达到均衡网络能耗的目的,延长普通节点的生存周期。仿真结果表明,基于差分的路由分簇协议能有效均衡网络中节点的能量消耗,显著延长网络的生存周期并提高网络能量利用率。     

基于OCBC的WSNs分簇优化策略

针对无线传感器网络(WSNs)能量负载不均衡问题,为延长网络生存周期,提高能量利用效率,提出了一种基于OCBC的分簇优化策略.首先,通过经线和纬线对网络进行非均匀划分,同时根据节点的地理位置和剩余能量来竞选簇首.然后,非簇首节点选择距离较小且能量较大的簇首加入,从而构建成簇.仿真结果表明:该策略很好地促进了网络能耗均衡,延长了网络生命周期.     

一种基于节点密度的无线传感器网络路由协议

能量问题一直是制约无线传感器网络(WSNs)发展的问题。成簇算法可以很好地降低网络通信能耗。分析已有的各类成簇算法,在LEACH协议的基础上,改进了簇头节点的选取方式。讨论了网内簇头个数的选择,然后以网内节点密度为参考选取簇头,通过赋予不同的参数来比较节点密度对协议运行的影响。仿真结果表明:改进的算法有效降低了通信能耗,延长了网络的生存周期。     

一种LEACH协议的多级分簇改进算法

LEACH协议的簇头节点分布不均,导致网络负载不均衡.为此,提出一种LEACH协议的多级分簇改进算法.将网络划分为若干小单元,采用多级分簇相结合的方法,在簇头节点选举过程中引入节点剩余能量作为参考度量,以减少簇头节点与sink 节点之间的通信能耗.仿真结果表明,当网络规模增加到200节点时,该算法在第420轮出现第一个死亡点,优于LEACH协议,能延长网络生存周期,降低网络能量消耗.     

基于PSO的无线传感器网络节能分簇协议

针对如何最优化组簇、降低簇内节点能耗的同时均衡整个网络能耗的问题,提出一种基于PSO的紧凑且具有能量感知和基站距离感知能力的集中式网络分簇协议,粒子适应值函数基于簇头和簇内节点的欧氏距离、簇头节点能量、簇头与基站距离这3个因素定义。仿真结果表明,该协议能有效降低节点死亡速度,延长网络生存周期。     

基于多重竞争的无线传感器网络簇头选择算法

无线传感器网络(WSNs)需要简单而有效的算法提高网络的生存周期.在经典的分簇算法LEACH基础上,根据节点剩余能量进行竞争,剩余能量大于阈值的节点可以选为簇头.在选择簇头时,各节点设置延时时间,根据邻节点数、到已选定簇头的距离2个因素进行竞争,选择合适的节点成为簇头.算法稳定了簇头数量,并使簇头分布更合理.仿真和数据分析表明:算法能显著提高网络的生存周期.     

一种能量优化WSNs非均匀分簇路由协议

为解决无线传感器网络多跳路由协议的“热区”问题,基于对EEUC协议的分析,提出了一种能量优化的WSNs非均匀分簇路由协议EOUCR（Energy Optimized Uneven Clustering Routing protocol）。该协议在簇形成阶段以候选簇头的剩余能量、其邻居节点的平均剩余能量和该候选簇头与SINK节点的距离作为竞选簇头的参数,且簇头竞争半径的选取考虑了成簇能耗,在此基础上形成了不同几何尺寸的簇,可减少“热区”内簇的簇头轮换次数,均衡网络负载。EOUCR在簇间多跳路由通信中引入了唯一与SINK节点通信的根节点,其他簇头则通过中继节点或直接与根节点通信,克服了EEUC能耗大且不均衡的不足,从而有效地解决临近SINK节点的“热区”问题。仿真实验结果表明,EOUCR能够更有效地节约节点能量、均衡网络能耗、延长网络生存周期。     

基于负载均衡的簇间路由协议

针对无线传感器网络簇头节点负载不均衡的问题,提出一种基于负载均衡的簇间路由协议.该协议通过记录邻居簇头节点到Sink节点的最小跳数信息建立到Sink节点的多条路径,根据簇节点的剩余能量和负载选择合适的路径进行路由,从而实现了簇头节点间的负载均衡.仿真实验结果表明,该路由协议能有效地均衡网络负载和簇头节点能量消耗,减少数据传输延迟,延长网络生存时间.     

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.