基于目标覆盖的无线传感器网络的连通性优化部署方法

覆盖控制技术研究无线传感器网络空间资源的优化分配,以满足用户的感知需求.覆盖节点的连通性是覆盖研究的关键问题,决定了感知数据能否最终传递给用户.已知的研究并未涉及目标覆盖确定部署应用的连通性问题.因此,分析了目标覆盖中的连通性问题,首次提出针对目标全覆盖与维护节点集连通性关系的连通临界条件;针对连通性条件无法满足的情况,提出了一个维护连通性的优化部署方案.该方案首先建立连通子集间的最小生成树,构造连通候选集;然后,基于连通候选集,利用遗传算法得到优化候选位集.仿真实验表明,提出的优化部署方案既实现了对目标集的全覆盖,又维护了连通性,并使候选位集的元素个数更少.     

无线Mesh网络路由协议研究

无线Mesh网络是无线接入的关键技术,主要是为了实现局部范围内的无线覆盖,增强网络的系统容量和连通能力,提高系统的抗毁性和自愈能力.在构建企业网络等方面有着广阔的应用前景,本文重点对无线Mesh网络的路由协议进行了研究.     

无线传感器网络节点部署问题研究

节点部署是无线传感器网络(W SNs)研究的一个基本问题。合理的节点部署方式有助于提高网络工作效率,优化利用网络资源。针对与节点部署相关的覆盖、连通、能耗三方面基本问题,对现有主要研究成果进行了分类和比较,讨论了三者之间的关系,总结性地提出并分析了网络覆盖和连通性能的评价标准。     

无线传感器网络三维表面k覆盖多连通部署方法*

无线传感器网络中覆盖连通问题是基本且重要的问题,三维表面作为无线传感器网络中的一种特殊情形,对应于现实世界中的山体,为了解决这类与实际应用密切相关的问题,提出了三维表面k覆盖多连通部署方法。该方法结合三维表面的地形特征,首先在目标区域自由选择网格大小进行划分,接着在各网格之间建立多连通关系,再通过方向梯度概率感知模型在网格内先构造k覆盖集,然后利用最小生成树算法构造连通图,最后找出关节点构造双连通图。大量仿真实验表明,该方法能够对目标区域进行完全覆盖和连通,并且能保证网络的健壮性。     

无线传感器网络连通k覆盖问题及其解决方案综述

覆盖控制是无线传感器网络的一个基本问题,通过对网络空间资源的优化分配,来更好地完成环境感知和有效传输等任务。作为覆盖控制理论的研究热点之一,连通k覆盖问题研究如何从随机部署的大量传感器节点中选择一部分节点激活,使得任意监测目标都被至少k个不同的活跃节点同时覆盖,而且所有活跃节点都是通信连通的。本文分析了无线传感器网络中连通k覆盖问题的系统模型和算法评价指标,介绍了一些典型的近似算法并对其进行了分析和比较,最后进行了总结和展望。     

无线传感器网络连通忌覆盖问题及其解决方案综述

覆盖控制是无线传感器网络的一个基本问题,通过对网络空间资源的优化分配,来更好地完成环境感知和有效传输等任务。作为覆盖控制理论的研究热点之一,连通k覆盖问题研究如何从随机部署的大量传感器节点中选择一部分节点激活,使得任意监测目标都被至少k个不同的活跃节点同时覆盖,而且所有活跃节点都是通信连通的。本文分析了无线传感器网络中连通k覆盖问题的系统模型和算法评价指标,介绍了一些典型的近似算法并对其进行了分析和比较,最后进行了总结和展望。     

无线传感网络中部分覆盖与拟连通冗余节点的研究

随机部署的无线传感网络通常包含大量的覆盖与连通冗余节点,这些节点不仅造成大量的能源浪费,同时影响网络的性能。为此,需要对网络中的覆盖与连通冗余节点进行有效的调度配置。考虑到无线传感网络中覆盖与连通冗余节点识别算法的复杂性,提出了一个新的“部分覆盖与拟连通的冗余节点”概念,它对网络具有同覆盖与连通冗余节点类似的影响,与覆...     

RGA-D：一种无线传感器网络覆盖优化方法

研究了无线传感器网络覆盖优化问题,针对传感器节点随机部署、分布不均,传统覆盖优化算法一般只考虑网络部署后单次优化的问题,提出基于节点冗余和覆盖集冗余的计算方法,用网络的局部特征表征全局特征,改进了网络覆盖模型。并在此基础上提出RGA-D算法,利用遗传算法计算覆盖集,同时考虑节点和覆盖集冗余度,对网络整个生存期进行全局优化。仿真实验表明,RGA-D算法能在活跃节点数和网络覆盖率之间达到平衡,解决了网络生存期后期容易出现覆盖盲区的问题。     

无线Mesh网络性能分析及协议优化研究

以链路作为网络图的考察点构建无线多跳干扰图模型,据此分析无线Mesh网络容量优化问题,将网络性能优化转化为图论中的“网络最大流”问题。从网络负载的均衡控制、多跳转发的路由优化、链路速率的自适应方法3个机制着手对无线 Mesh网络协议进行优化。理论分析与仿真实验结果表明,该模型的误差率可控制在10%以内,有效提升Mesh网络性能。     

无线传感器网络中基于Voronoi图的覆盖和连通综合配置协议

着重研究无线传感器网络随机部署下的覆盖和连通问题的解决方案,尤其是当无线传感器节点的通信半径Rc与感应半径Rs之比小于2时的解决方案.本文提出了无线传感器网络中一个基于Voronoi图的覆盖和连通的综合配置协议(VIP).该协议采用了一种分布式节点冗余判断算法以判断无线传感器网络中节点的冗余性,并让节点据此来对自身进行相应的职能调度.该协议能够在Rc/Rs为任意值时保证网络的覆盖和连通性能.本文还将该协议进行了推广,使得该协议能够满足覆盖度和连通度动态变化的要求,保证网络的k-度覆盖和k-度连通.     

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.