基于立体声信号的声源定位算法研究

提出了一种基于立体声信号的声源定位算法.算法主要分为两个步骤:先进行声达时间差估计,并从中获取传声器阵列中阵元间的声延迟;再利用荻取的声达时间差,结合已知的传声器阵列的空间位置和声速进一步定出具体声源的位置.实践结果表明,该算法是一种准确度高、稳定性好的声源定位方法,并且更加有利于实时声信号的处理.     

近地炸点声定位算法研究

针对四元十字阵被动声定位算法存在定位精度受目标方位角影响的问题,提出基于时间差技术的五元十字阵算法;研究了五元十字阵阵元间的几何关系与参数的计算,利用球面坐标法及最小二乘法推导了目标定位计算式,进行了系统误差分析;实验结果表明,该算法提高了炸点的测距与测向精度,改善了目标方位角对弹丸炸点的定位精度的影响;与四元十字阵算法相比,五元十字阵算法在距离、方位角和俯仰角的误差分别是1.33m、0.0003°和0.44°。     

遗传算法用于波达方向估计的线阵优化

利用遗传算法优化阵列设计来改善声目标波达方向估计性能.研究波达方向估计采用信号相位匹配原理的奇异值分解法SVDSPM,利用遗传算法对线阵进行了优化.优化时,阵列孔径不变,将阵元数目作为优化变量,优化目标是降低DOA估计误差.仿真结果标明:优化后在阵元数目减少的情况下,DOA估计偏差和均方误差更小.而且优化的阵列有好的低信噪比及宽带信号波达方向估计的能力.     

基于声矢量阵的宽带信号源方位估计

由于目标特征和水声信道的复杂性,阵列所接收的往往是宽带信号,它具有携带目标回波信息量大、混响背景相关性弱的特点,因此有利于信号的检测、参数估计和目标特征的提取.声矢量阵单个阵元能同时测量声场中的声压量和3个正交的质点振速分量,相对于声压阵,它能获取更多的声场信息.因此论文通过均匀声矢量阵运用FFT插值和RSS聚焦的MUSIC算法对宽带相干源DOA估计进行了研究,改善了对弱相干信号源的方位分辨和估计性能,实验所获得的仿真结果表明了该方法具有较高的参考价值.     

浅谈基于时延估计算法的声源定位技术

声源定位算法的关键是在不同的收集时间延迟估计在阵元阵列的声信号.在时延估计算法中有两个重要的概念.即时间延迟和时间延迟估计.时间延迟估计是指使用信号处理和参数估计方法的原理以及声源信号的时延估计来进行测定,以确定声源信号的空间距离,空间定位和运行速度等相关参数.     

声传感器阵列的实验研究

海洋中对目标的判决主要依靠于水听器阵列对水声信号的检测。为了对比声压阵与矢量阵对信号的检测能力,首先计算机仿真了声压阵和矢量阵的增益及其对目标方位的估计,而后加以实验验证。实验结果表明,矢量阵的增益高于声压阵,且其克服了声压阵左、右舷模糊的问题,能精确的对目标方位进行估计并完成对水下运动目标的航迹跟踪,从而验证了矢量阵的优越性。     

具有声定位功能的无线传感器网络节点设计

介绍一种具有声定位功能的无线传感器网络节点,可以实时测量目标节点的方位和距离。对目标方位的估计基于四元十字阵列的时延估计法,对目标距离的估计采用TDOA机理的测距原理。实验测试表明,整个系统在空闲状态下的电流不大于20 μA,在15 m的范围内,距离误差小于3%,方位角误差则随着采样率或阵元间距的增大而减小。     

基于声测量原理的多用途空间目标定位方法研究

多种类的目标定位使用实时声测量方法与现有电子雷达或光学测量方法相比,具有反电子干扰、反低空突防、隐蔽性好、响应时间快及设备简单等优点。针对现有声测量方法所采用的平面或立体声传感器阵的测量精度低和测量系统应用单一的问题,提出了基于六面锥体声传感器阵的测量方法,推导了该阵列的基本定位算法和模型,进行了测量系统不确定度分析和构建,经实验证明测试系统测量误差不大于±5%。以六面锥体声传感器阵为主所构成的测量系统,可用于对空射击弹目/炸目偏差、地面侦查炮位及防空预警。     

基于DSP的雷电定位系统设计

结合雷电电磁辐射和雷声能谱的特点,提出以声传感器组成五元十字阵接收雷声实现雷电定向,以声电延时计算雷电距离,以计算雷声能量从而表征雷电能量给出雷电强度的雷电定位方法。并给出了基于DSP的系统设计思路。根据现有资料估计,系统有效探测距离可达20～30km,有望达到±5°的俯仰角估计精度和±2°的方位角估计精度,距离估计精度小于340m。     

狙击手声被动定位模型仿真分析

为了更有效地打击狙击手,降低狙击手的威胁和伤亡率,针对狙击步枪激发时产生声波的特点,设计了狙击手声探测定位模型.模型采用短基线平面四元十字阵的传声器布阵方式,基于该传声器阵列建立了数学模型和推导了定位公式,并进行精度分析,重点仿真了时间差测量误差对探测精度的影响.结果表明基于四元十字阵的狙击手定位模型具有较高的定向精度,但是定距精度受时间差测量误差和阵列尺寸影响较大,探测同一目标时,时间差误差越小、传声器阵列尺寸相对较大时,具有良好的定距精度.该仿真结果为研制小型便携的狙击手被动声定位设备提供了参考.     

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。