改进QGA在WSNs节点部署中的应用

对含有障碍区域的无线传感器网络（WSNs）节点部署问题进行研究。建立节点探测模型和网络覆盖率评价方法,基于概率传感器模型提出一种部署方式,即对障碍区域进行随机布撒节点,确定区域采用量子遗传算法（QGA）寻找最优节点部署位置,实现对同构WSNs节点构成的目标区域的高效覆盖。仿真结果与GA,QGA相比：改进QGA有效提高了算法整体的搜索能力和收敛速度。     

基于虚拟力和多种群粒子群的覆盖优化HSN节点部署并行算法

针对异构传感器网络中由于节点随机部署而导致覆盖盲区和覆盖冗余的问题,以最大化网络的覆盖率为目标,设计了一种基于虚拟力和多种群粒子群的异构移动节点部署并行算法;首先建立了改进的异构节点概率感知模型和目标优化函数,然后采用虚拟力算法在虚拟力的作用下引导节点移动进行初始部署,为了进一步提高网络的覆盖率和部署的效率,采用改进的多种群粒子群并行算法实现对节点部署的寻优,并定义了具体的部署算法,为了增强网络的鲁棒性,设计了一种当节点失效时的自适应节点替换机制;仿真实验表明:文中方法得到的平均网络覆盖率为95.6%,与其它方法相比,具有较高的网络覆盖率和较少的部署时间,具有较大的优越性。     

基于改进免疫遗传算法的K覆盖异构传感器节点调度

为了实现无线传感器网络监测区域目标点的多重覆盖,设计了一种基于改进免疫遗传算法的异构传感器节点调度算法实现目标点的K重覆盖;首先,在传统的概率感知模型中加入剩余能量和感知能力因素,得到改进的概率感知模型,并设计了以最小化节点数并满足覆盖度约束的目标函数;然后,采用改进的免疫遗传算法对节点进行调度,最后,给出了具体的采用改进免疫遗传算法实现WSN异构节点调度的具体算法;仿真实验表明:文中方法能在满足K覆盖约束前提下实现监测区域的节点调度,与其他方法相比,活动节点数平均多7%,具有较长的网络生命周期和较少的网络能耗。     

基于感知概率的无线传感器网络节点部署算法

研究无线传感器网络节点部署优化问题,传感器节点的部署在一定程度上决定了无线传感器网络的性能和使用寿命;针对随机部署的无线传感器节点,提出一种基于感知概率模型的节点部署方案;使用证据理论通过计算对节点周围区域的综合感知概率,将虚拟力算法进行改造,使传感器节点向感知概率低的区域移动,实现对监测区域的最大覆盖;仿真结果表明,该部署算法实现节点合理分布,提高网络的覆盖率,减少节点的移动距离,达到延长网络使用寿命的目的。     

一种混合异构传感网的覆盖洞修补算法

传感网感知节点部署的随机性以及节点能耗殆尽、损坏退出等问题使网络中存在覆盖洞, 利用移动节点来修补覆盖空洞是当前较为可行的方法. 假定网络在静态节点和移动节点处混合, 并且在节点感知半径异构的情况下,研究如何通过移动节点重定位来修复感知覆盖洞, 同时兼顾移动距离或能耗最小以及修复后的感知覆盖率最大化来优化感知覆盖性能. 针对移动节点覆盖洞修补规划的NP-hard 问题, 结合遗传算法, 提出一种覆盖洞修补算法来求解最优解. 仿真实验结果表明, 所提出的算法相比于同类算法能够更有效地修补漏洞并兼顾节点能耗以及感知覆盖率.

     

混合WSNs中基于多目标优化的覆盖控制算法

针对无线传感器网络( WSNs)随机部署产生的区域覆盖率低、节点利用率差和能量不均衡的问题,引入移动传感器节点,将快速非支配排序遗传算法Ⅱ( NSGA-Ⅱ)运用到混合无线传感器网络覆盖控制部署并进行改进,采用分层编码策略,引入删除算子避免早熟,自适应改变交叉、变异概率提高局部搜索能力,获得较优解集后基于决策者信息偏好选择最优目标.仿真实验结果表明:有效解决了WSNs覆盖控制问题,可以在网络覆盖率最大化的同时,节点利用率较大且能耗系数较低,延长网络寿命.     

基于Delaunay三角划分策略的WSN区域覆盖优化研究

针对无线传感器网络在对初次抛洒节点形成的覆盖漏洞进行二次部署的过程中,传统几何学方法难以运用于概率感知模型的问题,提出一种基于Delaunay三角划分策略的无线传感器网络区域覆盖优化算法——DPSO算法。首先对监测区域内随机抛洒的静态节点和监测区域边缘顶点进行Delaunay三角划分,以得到静态节点三角网,结合无线传感器网络节点的概率感知模型证明三角形内部存在完全未覆盖区域即覆盖漏洞;其次将通过筛选得到的三角形形心集合作为粒子群优化算法的初始解集,利用改进的粒子群优化算法完成对移动节点的二次部署,以达到修复覆盖漏洞的目的。实验表明,所提出的基于Delaunay三角划分策略的优化算法能够有效修复覆盖漏洞,使区域覆盖率得到显著提高。     

基于遗传算法的无线传感器网络重新部署方法

研究了无线传感器网络在受限移动能力条件下的重新部署问题.针对节点的运动模型为跳跃式移动,提出一种基于遗传算法的重新部署算法.算法以节点的跳跃方向为遗传算法的基因,适用度函数同时考虑了最大化覆盖率和最小化移动总距离.仿真实验表明,在各向同性的感测模型中,此算法优于文献[8]提出的FBSD算法,能实现节点的最优运动规划,并且在有向感测模型中,此算法也能有效提高网络覆盖率.     

基于改进粒子群的无线传感网络覆盖优化方法

常规的无线传感网络覆盖方法一般采用三角划分策略,存在覆盖节点分布不均匀、覆盖范围有限、覆盖率较低等不足,具有较大的局限性。针对此问题,引入改进粒子群算法,提出一种全新的覆盖优化方法。首先,设计无线传感网络区域覆盖,使传感器节点均匀覆盖在整个待监测物体所在区域;其次,建立节点感知模型,实时反映像素点与无线传感器节点距离的动态变化;最后,设计基于改进粒子群的覆盖优化算法,实现无线传感网络覆盖率最大化的目标。实验结果表明,所提方法能够显著提高网络区域覆盖率,覆盖率均在96%以上,全局覆盖优化能力较强。     

动态视觉传感器网络中的节点目标覆盖机制

动态视觉传感器网络是一个新的研究课题,节点目标覆盖是其中的一个基本问题,它反映了网络的监测性能.对于动态视觉传感器网络的有向感知模型,节点目标覆盖问题需要考虑如何调整节点的位置和方向实现利用最少节点最大化网络覆盖能力.针对这一问题,提出一种改进的遗传算法寻找最优位置和方向,通过对传统遗传算法的交叉过程进行改进,加强了算法局部搜索能力.仿真结果表明:算法能有效地收敛到最优解,利用最少的节点数实现网络覆盖最大化,提高了网络性能.     

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.