基于CAN总线的分布式监控系统设计

针对传统的承压锅炉监控系统中存在的问题,设计了一套基于CAN总线的智能监控系统.选用STC89LE54RD 为微控制器,SJA1000为CAN控制器,PCA82C250为CAN控制器接口芯片;同时,还选用了先进的DS1822与PPT-R传感器,实现了CAN网络的数据采集、状态智能监控和数据存储.实际应用表明,系统工作稳定、可靠.     

基于CAN总线的智能电动执行器设计

介绍了一种基于CAN总线的智能电动执行器,该控制器以TMS320F2812 DSP为核心处理器.给出了控制器的硬件系统设计、软件设计原则和控制方法.其中带CAN总线接口的DSP微控制器的选用,不仅可以满足复杂数据的计算,而且使得智能执行器可以通过CAN总线保持实时通信.提高了系统的实时性和可靠性.换相控制、智能校准、人机接口以及自校正和多种保护的设计提高了执行器的智能化水平.     

基于CAN与无线射频技术的煤矿监控系统设计

为了将CAN总线的现场控制优势和射频技术的智能无线识别优势结合到一起,设计了一种基于CAN总线和射频技术的煤矿监控系统。射频芯片选用Intel R1000,可支持EPCGEN2 915MHz RFID标准,处理器选用Samsung公司ARM92410芯片作为主控制器。     

专家智能电除尘器监控系统设计

针对目前国内火力发电厂电除尘器运行维护管理不佳的现状,运用CAN总线技术和专家系统相关理论设计了一种新型的智能电除尘监控系统.控制器单片机程序使用Keil C语言开发,上位机监控功能使用VB 6.0语言实现.研究了CAN总线的总体结构,对高压电源工作点的判断、低压振打控制、故障诊断、时序做了较详细的分析,并简要介绍了该监控系统的主要功能.     

基于CAN总线的分布式高校公寓智能抄表系统设计与实现

介绍了基于CAN总线技术的高校公寓智能抄表系统的设计.公寓智能电表利用CS5460进行电能测量,经过CAN总线控制器SJA1000完成CAN总线收发数据,通过CAN总线在公寓内进行通讯,各公寓通过校园网连接到高校物业管理中心,组成高校公寓智能抄表系统,能进行实时数据采集及远程监控.     

基于CAN总线的海洋平台数据采集系统

介绍了一种基于CAN总线的数据采集系统,讨论了该系统应用在海洋平台这类特殊环境下的系统结构和现场节点的具体设计.系统由上位监控机、CAN网卡、智能网桥节点和智能采集节点组成,采用总线方式的网络拓扑结构,构成一种基于CAN总线的分布式监控采集系统.智能节点以AT89S52单片机为微控制器,使用SJA1000作为CAN控制器,可构成上行和下行网络通信波特率分别为500kbps和250kbps的CAN网络.详细分析了该系统的硬件组成,应用层协议和通讯流程.系统已应用于某海上平台的环境载荷的监测,提高了数据传输的可靠性,为平台的安全运行和结构的优化设计提供了科学依据.     

用于智能断路器的CAN总线接口设计与实现

针对目前智能断路器远程监控的发展趋势,在结合上位监控计算机实现网络控制的基础上,设计了一种基于CAN总线的智能断路器通信接口的设计方案,并对CAN接口与智能断路器的传输冲突进行了分析;详细设计了基于自定义应用层协议、以内嵌CAN控制器的MC9508DZ32为核心的CAN总线接口的软硬件设计与实现,形成一个完整的一主多从通信方案;实际运行结果表明,该通信方案为实现智能断路器的远程监控提供了一个解决方案,稳定性好,成本较低,具有广阔的应用前景.     

基于CAN总线的新型车辆配电网络管理系统

基于CAN总线的车辆配电网络管理系统,采用单片机、若干智能节点和一个显示终端构建.使用一种16位单片机控制各个智能节点.每个智能节点均由带CAN控制器的保险丝单元构成.单片机和智能节点之间通过CAN总线进行数据交换.用电支路的状态信息反馈到显示终端,实现对所有用电负载的远程监控.     

基于CAN总线的安全监控系统组成与分析

首先论述了加强安全监控系统性能的必要性,并对CAN总线性能特点进行了简要介绍.监控系统由多个智能节点和上位机组成,智能节点负责现场数据采集,上位机负责实现报警功能.文章给出了系统总体结构以及智能节点的硬件电路图和软件清单,并阐明了节点的构成以及设计中应注意的事项.通过系统仿真测试和分析CAN总线的可靠性及总线占有率,为系统设计提供了参考依据.论证了采用论文给出的基于CAN总线的安全监控系统结构是较好的选择.     

工程机械无线数传终端研究

针对工程机械远程监控与智能维护的需要.研究开发了一种基于CAN总线的无线数传终端.该终端基于工程机械本身的CAN总线控制系统,采用嵌入式技术.以数字信号控制器TMS320F2808和GPRS/GPS二合一模块XT55为核心,融合CAN、GPRS、GPS和DSP/BIOS技术,通过CAN网络和工程机械内部控制系统无缝集成,实时采集装备的运行状态参数,采用GPRS方式将数据发送至服务器.跨地域实验表明,该终端适用于对工程机械的远程监测,对实现设备的跟踪和主动维护具有积极的现实意义.     

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.     

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.     

Editorial: Special issue on recent advances in hybrid control theory and applications

正The demands of a rapidly advancing technology for faster and more accurate controllers have always had a strong influence on the progress of automatic control theory.In recent years control problems have been arising with increasing frequency in widely different areas,which cannot be addressed using conventional control techniques.The principal reason for this is the fact that a highly competitive economy is forcing systems to operate in regimes where     

Information for Authors

正Aim The Journals of Zhejiang University-SCIENCE(A/B/C)areedited by the international board of distinguished Chinese andforeign scientists,and are aimed to present the latest devel-opments and achievements in scientific research in China andoverseas to the world’s scientific circles,especially to stimulateand promote academic exchange between Chinese and for-eign scientists everywhere.     

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.