利用小波分析和云模型实现机车优化粘着控制*

分析了电力机车粘着控制系统的基本原理,建立了包含粘着特性的机车牵引力传递模型;利用小波分析消除车轮速度信号中干扰噪声,提高机车空转趋势识别的可靠性。云模型将模糊性和随机性有机地结合在一起,实现定性概念和定量表示间的转换;针对机车牵引系统的强非线性和不确定性,设计了云模型粘着控制器。通过与传统的粘着控制方法对比表明,小波分析和云模型粘着控制方法不但可以有效抑制空转,同时可以实现优化粘着控制。     

基于改进相位移法电力机车粘着控制

在研究电力机车优化控制的研究中,粘着控制是高速重载机车需要研究的关键问题.针对电力机车粘着控制传统方法在潮湿轨面中粘着利用率低及相位移法添加的正弦相移测相信号引起牵引转矩的波动,对电机产生不良影响等问题.为解决上述问题,设计了采用组合校正法及相位法相结合的粘着控制方法.在simulink中搭建机车动力学模型,应用改进后相位移粘着控制方法,仿真结果表明,新的粘着控制方法具有相位移粘着控制高粘着利用率优点,同时减小转矩波动对电机的不良影响时间,为机车粘着优化控制提供了参考.     

基于虚拟样机与二型模糊系统的机车粘着控制

为了抑制轮对空转,并使轮轨间的粘着处于极限状态,需要开发基于虚拟样机和现代控制理论的机车粘着控制技术。组建了包括电力机车多刚体动力学模型、电力牵引传动系统和控制系统的仿真平台。针对电力机车牵引系统的强非线性和不确定性,引入二型模糊逻辑以实现机车粘着控制。仿真结果表明,在该仿真平台上能够成功实现基于二型模糊系统的粘着控制,并且能够较好地抑制空转现象,实现优化粘着控制。     

基于轨面辨识的电力机车粘着控制仿真研究

针对避免因轨面粘着条件变化而造成车轮空转,提出了基于模糊理论的轨面辨识控制方法,将实时蠕滑速度和全维状态观测器实时估计,并利用粘着系数通过模糊逻辑推理判断的当前轨面与标准轨面的相似度,快速、准确地辨识出当前轨面的粘着峰值点.最后通过对牵引电机的输出转矩动态调整,以实现充分利用当前轨面轮轨间接触力的目的.在MATLAB/Simulink中建立四轴电力机车模型进行仿真研究.仿真结果表明:基于模糊理论的轨面辨识粘着控制方法有效的防止了车轮空转,提高了列车运行的稳定性和铁路运输效率.     

电力机车粘着控制技术的相关问题及其研究现状

电力机车的牵引力和制动力的形成依赖于轮轨间的粘着,粘着性能的优劣决定于粘着控制系统的设计。随着我国高速铁路建设规模的扩大和运载负荷的增加,提高机车粘着控制的性能更加重要。本文主要介绍了粘着系统的基本理论和当前电力机车粘着控制方法的研究现状,详细介绍了三种典型的粘着控制方法并分析了其利弊,最后对粘着控制方法的发展进行了展望。指出粘着控制的发展在于改进和有效组合现有控制方法并发展智能方法。     

机车粘着控制多学科仿真平台研究与实现

随着我国铁路运输的不断发展,机车的牵引力也不断增加.如何有效地增加机车牵引力,预防和控制打滑控制现象是粘着控制研究的重点.传统的粘着控制基于简化的二自由度机车数学模型,不能准确的表征复杂的机车模型.利用多体动力学仿真软件Simpack搭建机车模型,配合Madab/Simulink软件搭建的机车电机传动控制模型,利用Mathworks公司的基于模型设计方法,在传统仿真模型中加入DSP控制器,构建跨多学科的机车粘着控制仿真平台,仿真结果表明,多学科仿真平台能有效的实现机车粘着控制仿真.     

动态多子群QPSO算法及其在机车粘着优化控制中的应用

针对列车重载和高速运行时轮轨间粘着存在极限状态以及此时最优粘着利用能否获得的问题,利用所提出的动态多子群QPSO算法训练神经网络,并基于训练好的神经网络设计了机车粘着智能优化控制器,通过对电机转矩的动态调整,实现了轮轨间粘着的最优利用.仿真研究中,利用典型测试函数对所提出的动态多子群QPSO算法进行性能测试,证明该算法具有相对较高的寻优精度和效率,能有效提高神经网络的收敛速度和学习能力,将该算法应用于机车粘着优化控制中,得到了良好的控制效果.     

地铁牵引电机牵引特性仿真研究

针对地铁电力牵引特性,建立起直接转矩控制系统的仿真模型。恒转矩、恒功率和自然特性区采用不同的控制策略,为实现三个阶段不同控制方法间的平滑过渡,采用了速度施密特调节器以实现段切换代替点切换。论文应用Matlab／simulink软件对系统进行了仿真研究,模拟了地铁牵引电机在运行过程中牵引和突变负载工况,仿真结果表明系统具有良好的动、静态性能,满足机车运行的要求。仿真结果验证了控制方法的有效性和正确性。     

浅谈C64型万吨组合列车平稳操纵注意事项及建议

本文以神朔线SS4型电力机车牵引C64型万吨组合重载列车为研究对象,针对神朔线的线路特点对机车操纵进行研究分析,总结机车乘务员在操纵SS4型电力机车牵引C64型万吨组合列车时的注意事项,并提出建议,提高机车乘务员万吨组合列车操纵水平,降低万吨组合列车在运行中的纵向冲动,保障列车的安全平稳运行。     

基于FIP网络的电力机车牵引网络通信模块的研究

主要以基于FIP网络的电力机车作为研究对象,通过对电力机车的FIP网络和在其网络控制下的牵引控制单元(TCU)进行研究,搭建DDU半实物开发平台,开发平台由两台PC机加上相应的FIP网卡模拟机车上的MPU、TCU并和DDU实物组成FIP网络,从而实现整个机车的牵引通信模块的控制功能.     

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.