基于GPRS的风力发电机远程监控系统设计

为了克服目前风力发电机使用过程中人工检修和维护效率低、成本高、服务不及时的现状,设计了以C2000系列DSP-TMS320F2812(简称F2812)为核心处理器,以华为公司生产的GTM900-C无线模块为远程传输媒介的风力发电机远程监测分析系统.该系统利用F2812丰富的外设模块构建了系统的硬件并与GPRS技术相结合,成功研制了基于GPRS的风力发电机远程监控分析系统.该系统可实现风力发电机参数的远程无线监控分析.测试表明本系统能够实现长时间在线监测,并能正确地识别出故障.     

声振信号分离提纯的风力发电机故障诊断方法研究

由于风力发电机振动信号中掺杂大量声音信号,信号频带受到噪声干扰,致使风力发电机故障诊断效果不佳。为此,提出基于声振信号分离提纯的风力发电机在线故障诊断方法。分析导致风力发电机组声振信号干扰的因素。采用经验模态,将初始风力发电机在线故障信号分解成高频分量与低频分量两部分。采用小波阈值算法去除高频分量的噪声,并与低频分量作重构处理,得出风力发电机的实际故障振动信号。建立反向传播(BP)神经网络训练模型,使用粒子群优化算法得出该网络最佳的权值矩阵与偏置向量,并凭借网络训练算法诊断出故障数据的位置与类型。试验结果表明,所提方法在线故障诊断精度高,并能保证其训练效率与收敛速度,具有较高的实用价值。     

基于多源信息融合的风力发电机故障诊断研究

根据双馈风力发电机的工作原理和常见故障类型,对其故障诊断难点及常见的故障监测处置方法进行研究,并基于多源信息融合技术建立了风力发电机故障诊断系统,该系统通过加权融合振动信号、电流信号及温度信号,对机组的故障监测及处置工作提供更精确的指导,基于该故障诊断系统还进行了仿真应用研究,实现了故障的快速诊断和处置,具有较好的应用...     

面向高压断路器故障诊断的多源信号采集系统

针对高压断路器定期停电检修十分不便、状态监测采集信号种类单一的问题,该文设计了一种面向高压断路器故障诊断的多源信号采集系统。系统利用信号采集调理模块采集声音、振动及电流信号,调理后存入缓存模块;由AT32F437ZMT7读取缓存模块内信号数据,对之进行处理后利用以太网传输模块传至上位机,对信号数据进行显示、储存、回读以及时频域分析。结果表明,该系统可较好采集到断路器三类信号,并利用以太网模块稳定传输数据至上位机,实现断路器的状态监测和故障诊断。     

风力发电机在线状态监测仪的设计及应用

设计了基于TMS320 F2812芯片的DSP在线状态监测系统,此系统既可独立运行,又可与上位机配合工作,实现了数据采集、数据分析、故障预警、数据存储与上位机通信等功能.采集的数据经过滤波后,计算时域指标并将其与设定阈值比较,作为预警依据,之后对其进行FFT分析和Hilbert解调分析,分别得到信号的幅值谱和包络谱,以此来对风力发电机的状态进行监测.仿真分析和齿轮故障实验验证了DSP监测仪的有效性和可靠性.     

电力电子故障的Matlab仿真及其DFT分析

以三相桥式整流电路为分析对象，利用Matlab／Simulink环境下的SimPower Systems(SPS)模块库仿真得到各类故障下的输出波形，并将特定结果记录成MAT文件，在此基础上利用离散傅立叶变换将时域中的故障波形变换到频域，再对该离散信号进行频域分析，以突出故障特征，实现进一步故障诊断。     

基于LabVIEW的振动信号分析系统设计

针对机械故障监测的需求,开发了振动信号分析系统;采用LabVIEW图形化开发工具,系统实现了振动信号分析流程和基本的信号分析方法,能够对振动信号进行预处理,并从时域、频域和时频域角度对其进行特征提取;完成了基于仿真信号和实测的公开振动数据集的系统功能验证,采用希尔伯特-黄变换法对西储凯斯轴承的一组数据进行测试,结果表明,所开发的振动信号分析系统能够分辨出轴承故障的特征频率,相对误差为0.84%,同时具备参数配置灵活、结果显示直观、扩展性强的优势,为基于振动测试的机械故障监测提供了基础平台。     

基于OPC XML-DA的风力发电机移动远程监控系统

针对风力发电机远程监控问题,设计并实现一种基于移动互联技术解决方案,开发了基于Android操作系统的风力发电机移动远程监控手机客户端,通过Internet实现数据交互,开发了基于OPC XML-DA规范的的状态及故障的监控软件,解决硬件设备之间通讯接口的兼容及跨平台的问题.本文中介绍了该监控方案的总体框架,描述了OPC XML-DA服务器、移动客户端的设计思想,并进行了功能实现.测试结果表明,本系统能够高效的完成对风力发电机的实时监控.另外,该系统还能够应用于智能家居领域和各种工业控制领域.     

基于振动传感器的风力发电机故障检测算法

风力发电机长时间处于高应力状态下,易产生设备细小故障,若不能及时找出,会造成风电系统严重受损或瘫痪,为此提出了基于振动传感器的风力发电机故障检测算法。利用向量索引值集合及广义逆向矩阵,在压缩感知下匹配追踪信号,恢复缺失数值,经过经验模态分解后,加入白噪声求解信号分量平均值,识别信号的振动类型和能量变化,判断信号故障类型,利用逻辑回归模型分类信号是否属于故障信号,实现风力发电机故障信号分类及判断。仿真结果表明,所提算法可以准确区分正常工作状态和故障状态,迭代30次后可以将故障检测误差率保持在0.035。由此可知,所提算法能准确判断故障及所属类型,且精准度高。     

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.