改进簇头选举的分层传感网络能量优化算法

在无线传感网络中,为解决树状拓扑结构中簇头竞选算法不合理而造成能耗不均匀的问题,设计了改进簇头选举的分层路由能量优化算法,即在簇头选举时分别对阈值公式、簇头竞选算法有所改进.其中,阈值公式以节点所剩能量、节点到Sink节点间距离以及能耗因子为基准;而在簇头竞选算法中增加候选簇头的成员个数这一参数,可避免成员个数较多的节点成为簇头的几率,从而平衡簇头的能耗.通过与经典的LEACH和EOUCR协议的成簇算法仿真对比表明:提出的算法可以更好地平衡簇头能量耗损,从整体上延长网络生存周期.     

一种新型能耗优化的无线传感器网络成簇算法

能量消耗一直是限制WSN广泛应用的热门问题之一,能源容量的大小对各个传感器节点产生重要的影响.针对WSN中能耗过快,以及网络区域内能量消耗不均衡而导致的网络生命周期缩短的问题,同时为了提高WSN的能量利用率,提出了一种新型能耗优化的无线传感器网络非均匀成簇算法(UCNE).该算法首先根据节点的历史能耗来竞选簇头节点,将整个网络划分为不均匀的簇群从而平衡簇内节点通信与簇间节点通信的能耗.其次设立新的能量阈值作为网络重新分簇的标准,减少了频繁分簇造成的不必要的控制消息能耗.最后为了降低簇头节点的负担,竞选副簇头节点作为中继转发节点转发主簇头加工的数据并根据权值选择向前向簇头节点传递数据.通过对比相关协议,UCNE协议在平衡网络能耗,延长网络寿命方面表现更优.     

改进的无线传感器网络非均匀分簇路由算法

针对无线传感器网络中不均匀分簇引起能量空洞的问题,提出了改进的无线传感器网络非均匀分簇路由算法。该算法先根据节点剩余能量、节点到基站的距离、节点“度”和节点到簇头的距离等因素选举簇头;没有成为簇头的节点选择加入到距离最近的簇头所在的簇中,从而将整个网络划分为大小不等的簇;然后簇头再根据簇头剩余能量、簇头到基站的距离构造基于最小生成树的最优传输路径;通过簇内节点单跳、树内簇头多跳通信的方式将数据最终传输到基站。仿真结果表明,该路由算法能有效节约能量和均衡节点能耗,从而延长网络的生命周期。     

无线传感器网络能量均衡的非均匀分簇算法

无线传感器网络节点随机分布,针对均匀分簇容易造成网络中能耗不均的问题,提出一种能量均衡的非均匀分簇算法EBUCA(Energy-Balanced Unequal Clstering Algorithm)。该算法在簇头选举阶段,根据节点的剩余能量、节点所在区域稀疏程度来保证簇头的均匀分布;同时结合各簇头所在区域的节点密度与距sink节点的距离来构造大小不等的簇半径,使节点所在区域密度大或距离基站较近的簇半径较小,平衡了簇内和簇间的通信能耗。仿真结果表明与LEACH、DBCP、EEUC算法相比,EBUCA算法能够有效地均衡节点能耗,延长网络生命周期。     

基于传感器网络能量均衡分簇算法仿真研究

研究传感网络能量均衡分簇延长网络寿命问题。针对LEACH算法中簇首分布不均及簇首与基站一跳通信能耗大的问题,造成网络簇头的不均匀分布带来的能耗不均衡问题以及簇头的瓶颈等,为了解决上述问题,提出了一种基于能量高效的无线传感器网络分簇路由算法。算法首先在簇头选择过程中利用节点的能量、邻节点数以及每一轮中簇头的个数等参数设置节点当选簇头的优先度,使簇头均匀地分布在网络中;在簇的组建过程中利用能量参数设置簇的重建条件,达到减小簇的重建频率的目的。     

基于博弈论能耗均衡的WSN非均匀分簇路由协议

在无线传感器网络(WSN)的分簇路由算法中,节点间能耗不均容易引发 “能量空洞”现象,影响整个网络的性能。针对这个问题,提出了一种基于博弈论能耗均衡的非均匀分簇路由(GBUC)算法。该算法在分簇阶段,采用非均匀分簇结构,簇的半径由簇头到汇聚节点的距离和剩余能量共同决定,通过调节簇头在簇内通信的能耗和转发数据的能耗来达到能耗的均衡;在簇间通信阶段,通过建立一个以节点剩余能量和链路可靠度为效益函数的博弈模型,利用其纳什均衡的解来寻找联合能耗均衡、链路可靠性的最优传输路径,从而提高网络性能。仿真结果表明:与能量高效的非均匀分簇(EEUC)算法和非均匀分簇节能路由(UCEER)算法相比,GBUC算法在均衡节点能耗、延长网络生命周期等性能方面有显著的提高。     

能量高效的水声传感器网络多跳非均匀分簇算法

针对现有水声传感器网络(UW-ASN)分簇路由算法存在的能耗不均衡问题,提出了一种能量高效的多跳非均匀分簇(EEMUC)路由算法。通过节点到基站的物理距离建立网络非均匀分层模型,各层区域内的节点根据综合属性值选择簇头,靠近基站的簇的规模小于远离基站的簇。簇间采用多跳路由方式传送数据,从而均衡了簇头的能耗。实验结果表明,所提算法在簇头数目和节点的剩余能量等性能方面优于低能耗自适应分簇路由(LEACH)和能量高效的非均匀分簇(EEUC)算法,从而提高了水声传感器网络的能量效率,并延长了网络的生命周期。     

基于细胞膜优化算法的WSN分簇协议研究

针对无线传感器网络能量受约束的问题,为实现节点均衡能耗,平衡网络簇头分布,并最大限度地延长网络寿命,提出一种基于细胞膜优化算法的无线传感器网络能量均衡分簇协议。细胞膜优化算法具有良好的全局寻优和快速收敛能力,通过浓度与能量因素对节点进行划分,并结合距离因素完成全局均衡分簇,能够解决传感器网络中簇头分布不均匀、全局能耗不均衡等问题。实验结果表明,该协议具有对无线传感器网络进行快速全局均衡分簇的能力,且与LEACH算法和LEAH-C算法相比,在均衡节点能耗和延长网络生存周期等方面具有更好的性能。     

一种基于节点位置和密度的非均匀分簇路由算法

分析了现有分簇路由算法,提出了基于节点位置和密度的非均匀分簇路由算法。簇头选举阶段,考虑了节点的剩余能量,并引入竞争机制进行簇头选择;成簇阶段,综合考虑节点与基站的距离、节点密度以进行非均匀分簇,达到节点能耗均衡的效果,同时解决路由热区问题;簇间路由阶段,通过设立通信簇头节点,使簇间数据转发任务从簇头中分离,簇头节点只负责簇内的数据收集和融合,而通信簇头节点负责簇间数据传输,减少了簇头的能量消耗。实验结果表明,改进后的路由算法能够有效地均衡网络负载,并显著地延长网络的生命周期。     

无线传感器网络的分布式竞争路由算法

在WSNs体系结构中,路由算法是网络层的关键,分簇技术在路由算法中可提高WSNs的扩展性;提出一种竞争簇头,非均匀分簇和多跳路由相结合的WSNs分布式竞争路由算法(DSA);它的核心是构建一个高效的非均匀分簇算法,通过竞争的方式候选簇头,靠近基站的簇头为簇间的数据转发预留能量,根据节点的剩余能量、簇内和簇间通信代价,每个簇头在邻居簇头集中用贪心法确定中继节点;仿真表明,DSA算法能有效平衡了簇头的能耗、均衡了网络能耗、显著延长网络生存周期.     

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。