基于多信号流图的亚跨超声速风洞故障诊断方法

为了在风洞系统发生故障时实现快速准确的诊断与定位,提出了基于多信号流图模型的风洞测试性建模方法;针对风洞结构复杂、解析建模困难等特点,首先通过分析系统组成与设备的功能结构对风洞进行了层次性划分,并根据实际运行中出现的故障情况得到了风洞关键设备的FMEA结果;而后以FD-12亚跨超声速风洞为研究对象建立了系统的多信号流图模型,利用故障模式与测点对应关系建立了相关性矩阵;最后采用TEAMS-RT算法对系统的测试性水平进行了分析和评估,验证结果表明该方法对于风洞系统的测试性建模与故障诊断是有效的,为风洞系统健康管理相关研究提供了参考。     

基于多信号流图模型的等效故障注入样本选取

为了提高测试性故障注入试验的工程实践性,针对选取的故障样本不可注入或注入成本太高的情况,提出了一种基于多信号流图模型的等效故障注入样本选取方法。建立了系统的多信号流图模型,得到了故障-故障关联矩阵和故障-测试关联矩阵,并以提高故障样本注入率为目标,通过结合测试故障子集的概念,提出了等效故障注入样本的定义和选取方法。实例表明,该方法能够有效地提高故障样本的注入率,保证了测试性验证试验的顺利进行。     

基于多信号流图模型的导弹系统级故障诊断技术研究

为了实现对导弹装备系统级故障的诊断,提出了基于多信号流图模型的导弹故障诊断方法;该方法利用多信号流图模型建立系统的层次结构模型,在对导弹系统级测试性指标进行分析的同时,生成故障模式-测试相关性矩阵;在导弹测试出现故障时,利用故障模式与测试的相关性对相关性矩阵进行化简后,可将故障定位到具体LRU;最后,利用某型导弹电气系统对该方法进行了验证,试验结果证明,该方法对于导弹系统级的测试性建模与分析是有效的,利用该模型能够对导弹系统级故障进行准确定位。     

基于多信号流图模型的典型无人机测控系统测试性优化设计方法研究

针对无人机测控系统维修保障和故障诊断定位的实际需求,引入基于多信号流图模型,建立了无人机测控系统测试性优化设计方法。首先,介绍了多信号流图建模基本思路,给出了多信号流图的建模步骤;然后,结合典型无人机测控系统组成及工作原理,构建了无人机测控系统的多层次多信号流图模型,在此基础上开展了测试性预测和测试性优化设计,总结后给出了工程设计中的关键注意事项。研究结果表明：该方法可以有效提高无人机测控系统的故障检测率和故障隔离率,减小模糊组,优化后系统的测试性设计水平得到了提高,说明了该方法的有效性。     

测试性验证试验的故障注入方法优化研究

测试性验证试验是舰炮制导弹药测试性水平的主要验证手段,故障注入是验证测试性水平的一种有效方法。舰炮制导弹药封装严密,故障注入难度大,导致部分故障模式无法实现和故障覆盖率较低,如何进行故障注入方法的优化和减少故障注入的成本成为亟待解决的问题。从某型舰炮制导弹药的故障模式分析出发,研究了其故障传递特性,利用故障传递特性建立故障与状态、故障与故障之间的关系,并运用贝叶斯网络多树传播算法得到了测试性等效故障相关矩阵,使用等效故障代替无法注入的故障,有效提高了故障的覆盖率,优化了测试性故障注入方法,完善了测试性验证试验。最终使测试性验证试验更加完备,测试性水平的验证结果可信度更高,实现了某型舰炮制导弹药主要故障模式的全部覆盖。     

基于ATML的D矩阵诊断模型实现

故障诊断是自动测试系统/设备的重要功能,能否快速、准确的隔离故障是影响装备维修效率的重要因素。当今先进自动测试系统采用ATML系列标准,实现信息交换,其核心在于利用XML语言,通过规定的语法和结构描述测试系统、被测设备、测试流程和测试诊断结果等信息。针对故障诊断,标准定义了贝叶斯网络、D矩阵推理、诊断逻辑和故障树等故障诊断模型。其中D矩阵推理模型建立较容易,易于工程实现,被广泛应用。文章采用图形化建模方法建立了测试-故障依赖模型,描述了D矩阵模型建立方法、建立过程、推理规则和推理算法,并以某电台为例介绍了XML语言相关描述方法。最后基于D矩阵对电台测试性进行分析,根据评估结果完善D矩阵内容,优化推理算法,有效提高了电台故障隔离率,降低诊断模糊度。     

基于Linux的无人机故障注入软件研究

无人机故障注入软件利用故障注入技术实时地模拟飞行控制系统的故障,它主要用于飞行控制系统的故障注入与故障状态下动态性能测试和综合测试;它通过动态修改被测系统输入和输出信号达到故障注入目的,并能实时记录被测系统的响应从而分析不同故障对被测系统的影响程度;为了解决该软件在WINDOWS平台运行中所存在的缺点,设计构造了基于Linux的无人机故障注入与分析系统软件,完成了软件开发和故障分析;在无人机动态测试过程中,故障注入试验结果表明了这种方案的正确性和可行性。     

基于贝叶斯网络的车辆电源系统故障诊断方法

针对车辆电源系统测试点少且测试数据不完备的问题,提出一种多信号流图模型和贝叶斯网络相结合的故障诊断方法。利用多信号流图模型建立电源系统的故障诊断模型,得到系统故障源与测试信号对应的故障依赖矩阵,在此基础上,建立用于故障诊断的贝叶斯网络结构,根据历史数据完成网络的参数学习,并以故障后验概率最大为准则,实现电源系统的故障诊断。仿真实验验证了该方法的有效性。     

灵敏度矩阵分析的模拟电路故障诊断方法

在分析现有模拟电路多频灵敏度故障诊断方法的基础上,提出一种新的测试频率范围的选择方法,即灵敏度矩阵分析方法.灵敏度矩阵作为故障诊断方程的一个系数矩阵,它的奇异性制约着故障诊断方程解的存在性,而灵敏度矩阵又是测试频率的函数.通过化简故障诊断方程,建立灵敏度矩阵的奇异性与测试频率的关系,从而直接判断故障诊断方程的可解性.仿真实验表明,该方法可以选择一组最佳的测试参数和测试频段,准确地识别电路中的双故障,从而克服现有方法测试频率选择与诊断方程可解性之间的模糊性,增加求解故障诊断方程的可控性和提高故障的诊断率.     

基于故障确认的一体化测试性试验验证平台

针对目前测试性试验中缺乏有效的试验验证平台的现状, 创新性地提出了基于故障确认的一体化平台,具备装备功能性能测试、故障注入、测试性评估等功能。通过对测试性试验验证流程及步骤的论述,结合直接故障注入、等效故障注入、实际故障统计、测试性仿真分析等进行测试性综合评估,对一体化平台的硬件组成和软件框架进行了详细论述。最终将一体化平台应用于某型相控阵雷达的测试性评估试验,具有很强的工程推广价值。     

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.