基于蚁群的无线传感器网络能量均衡非均匀分簇路由算法

无线传感器网络(WSN)路由中,节点未充分考虑路径剩余能量及链路状况进行的路由会造成网络中部分节点网络寿命减少,严重影响网络的生存时间。为此,将蚁群优化算法与非均匀分簇路由算法相结合,提出一种基于蚁群优化算法的无线传感器非均匀分簇路由算法。该算法首先利用考虑节点能量的优化非均匀分簇方法对节点进行分簇,然后以需要传输数据的节点为源节点,汇聚节点为目标节点,利用蚁群优化算法进行多路径搜索,搜索过程充分考虑了路径传输能耗、路径最小剩余能量、传输距离和跳数、所选链路的时延和带宽等因素,最后选出满足条件的多条最优路径,完成源目的节点间的信息传输。实验表明,该算法充分考虑路径传输能耗和路径最小剩余能量、传输跳数及传输距离,能有效延长无线传感器网络的生存期。     

能耗均衡的多跳多路径认知分层路由算法

为了缓解频谱资源紧缺的现状,提高认知无线传感器网络能量消耗的均衡性,并减少网络的能量消耗,提出了一种适用于异构认知无线传感器网络的能耗均衡多跳多路径认知分层路由EMMCH算法。首先,根据节点剩余能量、节点位置和邻居节点密度改进了簇首选举概率;其次,结合竞争半径的概念,平衡区域簇首能耗;然后,根据节点信道可用性和剩余能量选举最优簇首,簇首总数依据动态选举的思想确定;最后,簇首节点选取剩余能量高、距离汇聚节点近且存在空闲信道的节点进行多跳传输路径规划,再结合沿途消耗和不均衡程度选取最优路径。仿真结果显示,与对比算法相比,EMMCH算法具有更长的生命周期、更高的稳定性、更多的数据传输量和更均衡的网络能耗。     

煤矿采空区无线传感器网络路由协议研究

针对现有的基于能量均衡的无线传感器网络路由协议不适应煤矿采空区应用的问题,提出了一种非均匀分簇能量均衡路由协议,即UCEB-CMF协议。该协议原理如下:优化候选簇首的选择机制,有效保证剩余能量大的传感器节点优先成为候选簇首;改进非均匀竞争半径的计算公式和候选簇首的竞争方法,在考虑剩余能量的基础上,增加了对簇首节点到Sink节点距离的考量,从而实现能耗均衡;针对煤矿采空区传感器节点易消亡的特点,提出了一种多路径路由算法,从而实现数据传输的持续性。仿真结果表明,该协议能有效均衡传感器节点能耗,延长无线传感器网络的生存期,适用于煤矿采空区。     

基于最小生成树的非均匀分簇路由协议

针对无线传感器网络中利用分簇技术,簇首到Sink节点通信采用多跳路由方式容易引起"能量空洞"的问题,提出了基于最小生成树的非均匀分簇路由协议.该协议在簇首选举阶段,以节点剩余能量、节点度、节点能量消耗速度为权重计算簇首竞争等待时间,选用簇首竞争等待时间小的节点为簇首,以均衡能量;簇形成后,以剩余能量、簇间的距离和能量消耗为参数构建基于最小生成树的最优传输路径通过多跳方式将数据发送到Sink节点.仿真结果表明,该路由协议能有效均衡能耗,延长网络生命周期,延缓"能量空洞"的形成.     

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。     

基于权值和代价函数的WSNs非均匀分簇路由算法

针对无线传感器网络(WSNs)中多跳通信造成的“热区”等问题,提出一种基于权值和代价函数的WSNs非均匀分簇路由(WCF-UC)算法.该算法采用权值的局部竞选簇首策略,簇首根据距离信息等构建大小不均的多个簇,通过考虑节点剩余能量、节点稀疏程度等因素来保证簇首的最优选择,簇内使用链式结构代替点对点通信,有效均衡簇内通信能耗.采用簇间多跳路由算法,使用一个代价函数,兼顾簇首剩余能量、簇内成员节点数量和位置信息,确定最优能量路径,完成簇间信息传输,平衡簇间通信能耗.仿真结果表明:与LEACH,HEED,EEUC等算法相比,该算法能够有效地均衡节点能耗,延长网络生命周期.     

蚁群优化的传感器网络路由算法

研究优化无线传感器设计,由于无线传感器通信能力、节点能量有限,远程环境下无法更换能源,节点能耗引起网络生命过短.在综合考虑了传感器节点剩余能量,为了延长网络生命周期,提出一种蚁群优化的无线传感器路由算法.算法根据节点当前剩余能量进行簇头选举,然后通过蚁群算法根据传感器节点距离和能量信息进行路由选择,并不断的更新簇头间的...     

一种适用于煤矿井下无线传感网的能量均衡路由协议

矿井无线传感网的拓扑呈长距离带状,节点间能耗不均问题十分严重。非均匀分簇策略能从全局均衡节点能量负载,在矿井中具有良好的适用性。针对矿井传感网的带状特性提出了一个簇规模自适应调节的能量均衡分簇路由协议。协议根据节点离汇聚点的距离、剩余能量及分布密度来构造规模不等的簇。簇首的竞选以节点相对于周围候选者的能量水平为依据,避免了低能量节点被当选为簇首。簇间多跳路由算法依簇首近似线型的分布特点设计,不但考虑链路能耗最优,亦注重转发节点间的能量均衡。模拟实验结果表明,该路由协议显著平衡了网中节点能耗,延长了网络生存时间。     

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。     

WSNs中基于动态竞争半径的非均匀分簇路由协议

针对LEACH协议成簇规模不合理、网络能耗不均衡的缺点,成簇阶段在LEACH协议的基础上,通过引入基于平均理想簇半径的簇首能量判决因子、"热区"关联判决因子、簇内紧凑性判决因子和节点密度判决因子来改进选举候选簇头的阈值计算公式。候选簇头以一种改进的动态竞争半径来竞选成为真正的簇头。数据传输阶段综合考虑簇头剩余能量、链路代价和数据传输方向3个因素选择下一跳路由。仿真实验结果表明:改进后的算法体现出较好的自适应性,能有效均衡网络能耗、延长网络生命周期。     

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。     

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.