无线传感器网络节点定位算法的研究

无线传感器网络节点数量大、资源有限,采用全球定位系统(GPS)定位设备来获取节点位置信息成本太高,研究适合无线传感器网络节点定位算法具有重要意义。通过分析无线传感器网络节点定位算法的基本原理,介绍已提出的几种节点定位算法,并进行分析比较。     

基于智能估计的无线传感器网络定位算法

节点定位是无线传感器网络的基本机制,位置数据是监测事件不可缺少的信息,传感器节点必须首先确定自身的位置.针对无线传感器网络的节点定位问题,提出了基于Free Search优化的智能定位算法,介绍了Free Search优化算法和智能估计的模型.该算法的基本思想是将参数估计问题转化为非线性函数的在线优化问题,利用Free Search获得未知节点坐标的最优估计.仿真结果证明,与最小二乘估计定位算法相比,新算法定位精度显著提高.     

基于无线传感器网络的室内停车场定位系统

在大型停车场中,对车辆的准确定位可以帮助用户快速找到车辆所在位置.不同于室外定位,GPS很难被应用于室内停车场中对车辆进行定位.本文提出的定位方式则使用成本低,体积小的无线传感器节点组成的无线传感器网络(Wireless Sensor Network)对车辆进行定位.针对室内停车场特点,在对现有测距技术进行了详细的分析和评估后,该系统采用了一种基于RSS的定位算法.针对于无线传感器网络节点运算能力有限的特点,该系优化了为定位算法,保证其实现简单,运行高效.同时,针对于无线传感器网络的能耗限制高的特点,该系统还将设计的定位算法与MAC协议相结合,并分析其能耗效率.     

GPS卫星跟踪数据的建模与仿真研究

根据卫星动力理论,建立了GPS卫星和低轨卫星的运动模型,再根据GPS定轨定位理论,建立了GPS跟踪数据的观测模型.最后在上述模型的基础上,提出了利用IGS数据产品进行低轨卫星以及地面观测站的GPS跟踪数据仿真的方法,并编制了相应的仿真程序.仿真结果表明文中的仿真方法能达到较高的精度,这对于论证搭载GPS的低轨卫星的定轨方案,评价其精密定轨算法,测试GPS数据处理软件,以及验证和比较GPS数据处理算法都具有较高的应用价值.     

无线传感器网络在智能公交中的应用

基于无线传感器网络构建成的城市公交实时信息采集系统,实现对城市公交的智能调度与定位.根据网络设计相应的传感器节点,编写相应的软件,实现公交车自动报站和电子站牌车辆信息显示功能.无线传感器网络技术与当前在智能公交系统中采用的GPS技术相比,本系统具有更高的性价比.     

无线传感器网络节点定位研究综述

深入探讨分析了无线传感器网络定位技术,从无线传感器网络定位算法分类、评价指标、距离相关和距离无关定位算法等方面进行分析,重点对比了几种典型算法,结果表明:不同的算法具有应用环境单一性,应结合实际需求选择合适的算法.研究分析了新型无线传感器网络定位方法,主要包括移动锚节点定位算法、三维空间定位算法和智能定位优化算法.总结当前无线传感器网络定位研究中存在的问题,并给出未来改进的研究方向.     

无线传感器节点定位功能测试平台

建模测试对无线传感器网络的研究以及相关商用产品的开发起着至关重要的作用.描述了用于监控无线传感器节点定位功能的测试平台的工作过程,构建了基于ARM嵌入式系统的无线传感器网络.采用相对定位方法,确定网络内各节点的相对位置,降低误差,以符合精度要求.分析了在μC/OS-Ⅱ操作系统的调度下,传感器节点利用GPS模块进行相对定位的流程,并对网络状态的显示界面作了相应介绍.利用该平台对传感器网络进行测试,所得定位数据符合实际情况,获得了预期的结果.     

基于遗传算法WSN节点定位算法研究

研究无线传感器网络节点定位问题.针对无线传感网络由于位置信息等原因而造成节点定位误差较大,精确度不高等问题缺陷,提出了一种改进的基于遗传算法优化DV-hop定位算法,并将算法应用在无线传感网络节点定位中,算法首先利用节点间的距离和锚节点的位置,在距离无关定位算法的最后一个阶段,采用遗传优化算法对DV-hop算法定位得到位置进行校正,在不增加传感器节点的硬件开销的基础上有效提高定位精度和扩大定位范围,仿真结果表明,改进的网络节点定位算法定位误差小和定位范围广等性能,与原始的DV-Hop定位算法相比定位误差明显减小,精度明显提高.表明算法是一种高效节能的定位算法.     

基于粒子群优化算法的WSNs节点定位研究

为了提高无线传感器网络节点定位的精度,提出了一种基于粒子群优化估计的无线传感器网络节点定位算法。该算法简单易实现,可调参数少,通过多次迭代寻优,以提高定位精度。仿真结果表明,新算法与常用的极大似然估计算法相比可以显著提高节点定位的精度和稳定度。     

基于车辆与车辆的车联网分布式协同感知定位

车辆协同感知定位是车辆定位的热点技术.针对车载自组织网络,本文在GPS卫星导航和车辆自身航位推算(DR)的基础上,利用车辆之间的到达时间(TOA)观测和车辆到车辆(V2V)的实时通信来设计一种分布式协同定位方法.针对协同定位中TOA测量函数的非线性和辅助车辆真实位置未知的问题,提出了一种基于改进无迹卡尔曼滤波(UKF)的协同定位算法.相对于传统的UKF协同定位使用GPS观测值作为辅助车辆位置,本文提出的算法将辅助车辆位置作为未知参数,扩维到状态向量,有效降低了辅助车辆位置误差对定位精度的影响. Monte Carlo仿真结果表明,利用TOA观测的协同定位精度明显优于仅利用GPS和DR的独立定位精度,且改进的UKF协同定位算法相比于传统UKF算法,具有更高的定位性能.     

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。     

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。