粒子群优化的无线传感器网络仿真研究

研究优化无线传感器问题,针对延长传感器网络的寿命,保证簇的平均分布,提高簇的负载均衡,从而减少能量消耗.传统算法在确定簇首过程中由于忽略了邻居节点的状态信息,容易导致簇内节点过早的出现盲节点现象,从而降低网络的生存时间.要解决上述问题,延长网络生命周期和有效降低能耗,提出一种粒子群优化的无线传感器分簇算法.在充分考虑了簇内邻居节点的能量和距离分布信息的前提下,通过粒子群优化分簇和簇首选择,并进行仿真.仿真结果表明,与LEACH算法相比,算法能有效地均衡网络节点的能量消耗和显著地延长网络寿命,并有效地避免了盲节点现象的过早发生.     

基于量子PSO传感网络分簇算法仿真研究

研究无线传感器分簇节点优化问题,针对无线传感器网络分簇算法由于簇头的不均匀分布带来的能耗利用不均衡以及簇头的瓶颈,导致能量过早消耗,网络寿命周期缩短.为了延长无线传感网络生命周期,提高能量利用效率,提出了一种粒子群(PSO)算法优化的无线传感器网络分簇算法.采用量子粒子群算法分簇策略使簇间能量优化平衡,使整个网络分成若干个虚拟网格,每个虚拟网格形成一个簇,采用唯一簇头选举法产生簇头,且簇内成员可以根据局部的信息调整簇的大小.仿真结果表明,提出的分簇算法很好的使网络的能耗达到了均衡,节约了簇头节点的能量,从而延长网络的寿命,为优化网络通信提供了依据.     

无线传感器网络分簇算法的仿真研究

针对无线传感器网络分簇中节点负载不均衡的间题,提出了一种基于免疫记忆粒子群优化算法的分簇算法.算法对能力异构环境下的无线传感器网络的适应性和扩展性较好,且节能高效,实现简单.该算法在每轮运算过程中,利用节点负载能力预评估因子和节点能量预评估因子对无线传感器网络进行区域分割,获得能量均衡及负载能力均衡的分区,并在分区中通过免疫记忆粒子群算法选取簇头,使簇头具有高能量、负载能力强的优点.仿真结果表明,算法不仅在能量有效性、负载均衡性方面有良好的效果,而且延长网络生命周期和缩短建簇时间.因此,该算法在解决无线传感器网络节点不均衡问题上具有一定的实用性.     

保持覆盖的无线传感器网络簇内节点调度方法

为了延长无线传感器网络的生命周期,提高节点能量利用效率,将簇与节点调度相结合,提出了保持覆盖的无线传感器网络簇内节点调度。首先将网络分簇,然后每个簇内的节点,按节点号自小到大的顺序依次计算每个节点与簇内邻居节点的距离,并判断所有距离小于监测半径的邻居节点能否对自己实现圆周覆盖,从而判断自己是否是冗余节点。利用Matlab仿真表明,一方面该算法可以有效减少网络的能量消耗,延长网络生命周期;另一方面该算法的调度效率与网络节点密度以及节点监测半径都有密切关系。     

基于PSO的无线传感器网络双簇头分簇算法

利用粒子群优化算法对无线传感器网络分簇算法进行优化,考虑簇内节点和簇头节点两者的位置及能量信息优化选择主簇头和副簇头。主簇头用以收集簇内节点的信息并进行数据融合,并将融合后的数据发送给副簇头。副簇头负责与基站进行通信。该算法可以均衡簇内的能耗,达到延长网络生命周期的效果。仿真实验结果表明,与LEACH算法相比,该算法可使网络生命周期延长50%。     

配电网中基于分簇定位的WSN节点故障定位研究

针对电网故障检测中使用的无线传感器网络节点定位精度较低,分簇不均问题,提出了一种基于DV￣Hop算法改进均值粒子群算法(PSO),首先DV￣Hop算法改进均值粒子群算法中粒子的速度与位移,使动态无线传感器网络重新定位簇头节点坐标更加接近真实值;然后递归神经网络学习算法迭代值逼近最合适的惯性权重值,优化均值PSO粒子群算法使其达到最优搜索能力。最后由Sink节点对每一次动态分簇后网络节点进行数据采集后对电能耗尽的节点进行无线充电。仿真结果表明,改进后的PSO算法比PSO算法聚类分簇误差更小,节点定位配电网故障的精确度提高12.8％,有效地延长了网络生命周期。     

基于离散PSO的分层多链无线传感器网络路由算法

针对无线传感器网络节点能量有限的特点,在PEGASIS协议的基础上提出了一种基于离散粒子群优化算法的分层多链无线传感器网络路由算法DPSO-MCRA.此算法把网络分为两层,通过离散粒子群优化算法建立多条低层链路来遍历所有节点;高层节点则自发地根据剩余能量以及到基站距离的平方大小竞争父簇头,依次选择最近的邻居链节点作为该链簇头,并由这些簇头节点组建簇头链.仿真结果表明,本文提出的路由算法与PEGASIS、GASA、ECR相比能显著缩短通信距离,减少和均衡能量消耗,从而延长了网络的生命周期,并降低了网络时延.     

基于粒子群优化的大规模传感器网络节点调度策略

针对资源受限条件下大规模无线传感器网络中协作目标跟踪问题,提出一个基于粒子群优化的节点调度方案.该方案利用高斯粒子滤波算法和方差交叉融合算法获得目标状态预测信息,进而选择下一时刻簇成员节点,并构造了通信能耗的代价函数,利用粒子群优化方法选择最佳的簇头节点,减少了节点调度的计算复杂度,同时保持了较好的跟踪精度.仿真结果验证了所提出方案的有效性.     

基于改进粒子群算法的WSN覆盖优化策略

为了实现WSN网络覆盖范围的最大化,延长网络寿命,本文在标准粒子群算法的基础上提出了一种无线传感器网络覆盖优化策略。通过粒子分簇并行搜索,采取碰撞理论使陷入局部最优的粒子迅速跳出,有效地避免了标准粒子群算法容易出现的“早熟”问题,提高了算法的稳定性。通过仿真实验分析了分簇数和碰撞阈值对覆盖性能指标的影响,仿真实验结果表明基于碰撞理论的分簇粒子群算法覆盖策略有效地优化了网络的覆盖性能。     

应用IPSO的无线传感器网络分簇路由算法

在基于分簇的无线传感器网络中,网络是通过附近传感器节点在转发信息到目的节点前进行冗余数据的融合实现节能,从而延长了网络的生命周期。但现存的算法在选择簇首节点的过程中由于忽略了邻居节点的状态信息,容易导致簇内节点过早出现盲节点的现象。进化类算法已经成功应用于许多方面,微粒群算法就是其中之一。提出了一种基于改进型微粒群算法的无线传感器网络分簇路由算法来优化分簇过程。簇首节点的选取综合考虑候选节点和邻居节点的状态信息。仿真结果表明算法的性能得到了较好的改善,并延长了网络的生命周期。     

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.