基于IMM-IKF的无线传感器网络非视距节点定位方法

针对非视距(NLOS)环境下的移动定位问题,提出一种基于交互式多模型-改进卡尔曼滤波(IMM-IKF)的无线传感器网络NLOS节点定位算法.算法在IMM算法框架下估计移动节点位置,采用两个平行的改进卡尔曼滤波算法对多个移动节点候选位置进行滤波处理,通过Markov链实现LOS状态与NLOS状态的转换,根据似然概率对两个滤波结果进行加权融合,从而获得移动目标位置.仿真实验结果表明,所提出算法可以有效抑制NLOS误差,实现精确定位.     

基于UWB的消防员室内协同定位算法

为了在复杂火场环境下获取消防员的精确位置,提出基于超宽带(ultra-wideband,UWB)的消防员室内协同定位算法,充分利用目标到UWB基站以及到其他目标的测距信息进行定位.采用线性拟合方式对测量距离中存在的标准偏差进行预处理;针对目标位置解算及非视距(non-line-of-sight,NLOS)误差缓解问题,...     

运用最优化原理的新型非视距抑制无线定位算法

无线定位中非视距(NLOS)误差的存在会显著降低传统定位算法的精度,因此论文提出了一种运用最优化原理的定位算法以对抗NLOS误差.该算法适用于存在固定节点与移动节点的无线传感网系统,并结合距离加权思想将NLOS环境中的定位建模为二次规划问题,最终得到节点的最小二乘位置估计.分析表明在固定节点数量较多或者存在视距(LOS)传输固定节点时,该算法可以显著削弱NLOS误差的影响.计算机仿真证实了这一分析,其结果表明,在NLOS环境下论文所提出的算法性能优于现有其他定位算法,同时该算法还具有不受固定节点数目限制和复杂度较低等优点.     

基于TDOA和RSS的可行域粒子滤波非视距定位算法

针对室内复杂环境下无线传感器节点的信号传播状态在LOS/NLOS之间切换的现象,提出基于TDOA和RSS的可行域粒子滤波非视距定位.首先采用基于TDOA和RSS两种测距模型的假设检验方法去辨识测量信号中是否存在NLOS现象,然后采用考虑NLOS测量信息的可行域粒子滤波方法对未知移动节点的位置进行定位.仿真结果表明,所提出的方法优于最小二乘法、普通的粒子滤波算法以及仅采用RSS测距模型的粒子滤波算法,具有较高的定位精度.     

非视距传播环境下的AOA定位跟踪算法

基于几何结构的单次反射统计信道模型,提出了一种在非视距(NLOS)传播环境下对移动台的到达角(AOA)的定位与跟踪算法.首先利用径向基函数(RBF)神经网络对NLOS误差进行修正,再利用最小二乘(LS)算法进行移动台位置估计,然后配合相关检测距离门对移动台进行跟踪.仿真结果表明,该跟踪算法能够有效地实现移动台的静态定位...     

ＮＬＯＳ状态信息辅助协方差矩阵修正的无线网络定位方法

非视距(NLOS)误差是影响无线定位精度的重要因素，其产生是由于实际环境的多变性，使其无法用一个准确的数学模型来表示。如何减小NLOS误差的影响是无线定位中需要解决的问题之一。针对该问题，本文所研究的定位方法通过视距(LOS)节点检测来获取测距结果中的NLOS状态信息，并基于该状态信息，对用于双步加权最小二乘(TS-WLS)定位算法的协方差矩阵进行修正，修正后的算法能够根据NLOS状态信息实现对不同测距结果的重要性加权，从而减小NLOS误差的影响。仿真结果表明，与以往的定位算法相比，本文算法能够拓展复杂NLOS环境下的适用场景并提升定位精度。     

基于BP神经网络的定位跟踪算法

提出了一种在NLOS环境下对移动台的定位与跟踪算法。利用BP神经网络对TDOA测量值中NLOS误差进行修正,再利用Chan算法进行移动台位置估计,配合相关检测距离门对移动台进行跟踪。仿真结果表明,该跟踪算法能够有效地实现移动台的静态定位与动态跟踪,性能优于基于Chan算法、LS算法、Taylor算法的静态定位与动态跟踪。     

基于改进集员滤波的港口自动跨运车状态估计方法

针对自动跨运车状态估计问题,设计改进的集员滤波算法,在未知有界噪声环境下,获取自动跨运车实时运动状态的估计信息.首先,将自动跨运车运动学模型进行线性化处理,同时考虑其转向因素和侧倾因素,得到车辆的动力学线性模型;其次,将可能存在的内外部扰动建模为未知有界噪声,进而设计改进的集员滤波器,通过获取状态椭球域实现对自动跨运车运动参数的状态估计,同时给出改进的集员滤波算法;最后,通过仿真实验验证所提出算法的可行性和有效性.实验结果表明,所提出的改进集员滤波算法具有良好的状态估计性能.     

基于阈值筛选的室内定位优化算法

针对室内超宽带（Ultra-Wide Band, UWB）的定位技术在复杂遮挡的环境下定位效果不好、定位不精确的缺陷,本文提出一种在Chan算法的基础上对粒子群算法进行优化的混合算法定位方法。首先利用Chan算法求出定位标签初始估计位置坐标,并在非视距（NLOS）环境下通过设置阈值θ以对Chan算法计算出的位置坐标进行筛选;将已知的基站接收到的距离差与用Chan算法求出的标签位置信息求出的不同基站间的距离差做差值和,若差值和小于该阈值则直接输出位置坐标,反之则将位置坐标作为粒子群算法的初始值,通过迭代优化不断追踪个体极值和局部极值,更新个体的位置和速度,寻找到全局最优解再进行输出。仿真结果与实际场地实验结果表明,与单一算法相比,本文提出的混合定位算法在非视距环境下的定位精度可提高27%~31%;收敛速度快,算法复杂度低,满足室内定位的要求。     

室内环境下基于IMM-EKF算法的移动目标定位

如何在视距(line-of-sight,LOS)与非视距(non-line-of-sight,NLOS)混合的室内环境中提高移动目标定位的精度,这是一项富有挑战性的工作.移动目标在室内环境移动时,其与传感器网络节点之间的信号传播在LOS与NLOS之间随机切换,导致移动节点定位精度下降.提出一种交互式多模型-扩展卡尔曼滤波(interactive multiple model-extended Kalman filter,IMM-EKF)定位算法.根据LOS?NLOS环境下不同的测距误差特性,在IMM框架中采用2个平行的卡尔曼滤波器(Kalman filter,KF)模型对测量距离同时进行滤波,根据滤波结果和测量值计算2个模型的似然概率,模型间的转换通过Markov链实现,2个KF滤波结果加权融合后获得IMM距离估计值.在EKF定位阶段,通过位置预测和更新估计出移动目标位置.仿真结果表明,IMM-EKF算法能够有效抑制NLOS对目标定位的影响,其定位精度优于单模型算法.     

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.