薄厚度有机防护涂层的太赫兹无损检测与多元回归分析

传统太赫兹检测数据处理方法中,介质层最小检测厚度受限于太赫兹在介质中的脉冲相干长度的一半.采用引入粒子群优化的多元回归分析方法来提高太赫兹检测有机防护涂层厚度分辨率.分别以太赫兹原始检测信号、傅里叶反卷积得到的脉冲响应函数、信号经平稳小波变换分解的细节系数为对象,提取不同特征参数建立相应的多元回归模型,并引入粒子群算法进行优化,最后用相应模型预测薄厚度涂层.预测分析结果表明:采用本文方法对太赫兹检测信号的平稳小波变换细节系数进行分析,能够有效提高太赫兹脉冲对薄厚度涂层的检测精度,有利于涂层涂装生产中的质量监控.     

基于平稳小波变换的铯谱和ECG信号的去噪方法

本文针对小波空间适应法在用于TOKAMAK铯谱信号以及ECG信号去噪中的缺陷,提出一种利用平稳小波变换来消除信号加性噪声的方法。对受噪声污染的信号进行多层平稳小波变换,避层估计平稳小渡变换细节信号中噪声的均方差并适当选取各层阈值．对平稳小波变换的各层细节信号进行不同的闭值处理,从而更好地抑制小波空间适应法消噪出现的Gibbs现象．较好地保持了铯谱信号和ECG信号的几何特征。     

基于MATLAB的奇异信号检测中小波基选择研究

小波分析是近年来发展起来的一门新的数学理论和方法，在图像处理、特征提取及数据压缩等领域都有着广泛的应用。该文介绍了小波变换及其用于信号奇异性检测的基本原理，重点研究了信号奇异性检测中小波基(又称母小波)及尺度的选择问题，提出了规则性系数相似法，即根据相似性，可以用平滑的小波，即规则性系数大的小波表示平滑的函数；用不平滑的小波，即规则性系数小的小波表示非平滑的函数。同时针对天然气管道泄漏检测这一具体的工程实例，采用该方法对管道发生微小泄漏时所产生的缓变信号进行了分析，仿真实验验证了该方法的有效性和适用性。     

基于自适应分解层数和阈值的小波去噪算法

为了更好地降低电能质量扰动信号中的噪声,提出了一种基于自适应分解层数和阈值的小波去噪算法.通过计算小波细节系数的峰值比,自适应地确定最佳小波分解层数,根据各层细节系数中有用信息和噪声信息的分布特性以及细节系数的正、负峰值比,动态调整各层细节系数的上、下阈值.应用Matlab对暂态振荡和脉冲信号进行去噪处理,并与传统硬、软阈值算法和一种改进小波阈值算法相比.结果表明:本文提出的自适应分解层数和阈值的小波去噪算法得到的信噪比和均方根误差均优于以上3种方法,重构后信号更接近原始信号,并且较好地保留了扰动期间信号的特征信息.     

管道阴极保护电位无线采集系统的研制

腐蚀是影响管道系统可靠性及使用寿命的关键因素,控制埋地管道腐蚀的公认做法是采用外加防腐层和阴极保护的联合防护。国内防腐层阴极保护电位检测多数仍采用人工逐点检测,操作不便且易造成误差。本文介绍了应用于管道阴极保护工况下、基于MSP430单片机和CC1101及ARM的无线采集系统的软硬件设计和构成,实现对阴极保护电位的无线采集及进一步处理。     

基于平稳小波变换的膈肌肌电信号降噪

为了去除膈肌肌电中的心电干扰,提出了一种基于平稳小波变换的“逆向”硬阈值的降噪方法。首先,对临床的膈肌肌电信号进行平稳小波变换,根据小波系数检测QRS并且确定心电干扰范围;其次,逐层估计心电周期范围的小波系数均方差,并且通过均方差计算各个心电干扰的阈值;最后,对各层心电干扰范围小波系数进行“逆向”硬阈值处理,并进行小波逆变换得到降噪后的信号。实验结果表明,该方法能够有效地去除膈肌肌电信号中的心电干扰,并且能够较好的保留膈肌肌电信号的信号特征。     

基于小波融合的射线图像增强算法*

提出一种基于小波融合的射线图像增强算法,利用射线成像的特点,对射线成像系统采集信号作分段灰度变换,将变换得到的多幅图像利用小波变换进行图像融合,以增强射线图像的显示效果。融合中采用低频图像的小波系数均值作为融合后的低频系数,高频图像根据梯度和一致性检测确定融合规则,调整高频小波系数大小,很好地将来自不同图像的特征与细节融合在一起,并对融合图像质量进行了对比评价。实验结果表明,这种方法能够在保留图像微小细节方面获得满意的结果,且优于传统的射线图像增强方法。     

小波变换在神经细胞传感器信号去噪中的应用

将神经元培养在半导体传感器芯片表面,构建出能够对细胞电生理特性进行长时程无损测量的神经细胞传感器,具有广阔的生物医学应用前景.由于生物信号非常微弱,采集到的信号往往难以满足实际检测的需要.本研究针对培养在光寻址电位传感器(LAPS)芯片表面的PC12细胞的胞外电生理信号,采用小波变换方法对其进行去噪处理.通过小波变换将信号分解为不同层次的小波系数,得到每一层的阈值.并根据每一层系数特点,按阈值进行分别处理,得到新的小波系数,最后根据该系数,重构了信号.对去噪后的信号进行频谱分析,发现有效信号频率集中在小于2 kHz的范围内,信噪比得到提高,表明小波变换是神经细胞传感器信号去噪的有效方法.     

平稳小波变换在膈肌肌电降噪中的应用

为了去除膈肌肌电中的心电干扰,提出了一种基于平稳小波变换的“逆向”硬阈值的降噪方法.首先,对临床的膈肌肌电信号进行平稳小波变换,根据小波系数检测QRS并确定心电干扰范围;其次,逐层估计心电周期范围的小波系数均方差,并且通过均方差计算各个心电干扰的阈值;最后,对各层心电干扰范围小波系数进行“逆向”硬阈值处理,并进行小波逆变换得到降噪后的信号.实验结果表明,该方法能够有效地去除膈肌肌电信号中的心电干扰,并且能够较好地保留膈肌肌电信号的信号特征.     

高压直流输电接地极对埋地油气管道干扰规律研究

针对高压直流(HVDC)输电接地极对埋地油气金属管道产生感应电压,造成管体腐蚀及气液联动开关误动作的问题,利用ANSYS建立金属管道感应电位耦合仿真模型,分析了接地极到管道距离、土壤电阻率、防腐层电阻3个因素对管道干扰的影响,并自主研制了HVDC对金属管道感应电位在线状态监测系统.仿真和实验结果表明:土壤电阻率的增加使得干扰电位呈线性增大,干扰电位随管道防腐层电阻增大而呈指数增加,接地极与管道距离变大,干扰电位呈指数降低.系统的数据采集模块达到了对信号的测定兼具稳定性且高准确度的要求,通过实验进一步验证了仿真中得到的干扰规律.     

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。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

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     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

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.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.