基于PLC和组态软件的油库罐区监控系统

设计了基于S7-300系列PLC和力控组态软件的油库罐区监控系统,介绍了其硬件结构和软件设计.该系统通过工业以太网实现上位机和PLC的通信,采用上位机双机冗余和PLC软冗余结构,可以充分发挥PLC和计算机的优势,有助于提高监控系统的可靠性.     

PLC与上位机监控系统的串行通讯实现

PLC与上位机监控系统的通讯技术是工业控制系统中的关键技术之一。以超薄快速铸轧板形控制系统为基础，在保证系统通讯安全可靠的前提下，设计了PLC与上位机监控系统最经济，可靠的通讯方案，采用功能强大的开发工具C＋＋Builder编制上位机通讯程序。该方案实现简单， 通讯可靠，可移植性强，适合于同类的工业控制系统。     

多种PLC数据采集系统的实现

PLC与上位机监控系统的通讯技术是工业控制系统中的关键技术之一。在保证系统通讯安全可靠的前提下,设计了PLC与上位机监控系统最经济、可靠的通讯方案,采用功能强大的开发工具VS2017编制上位机通讯程序。该方案实现简单,通讯可靠,可移植性强,适合于同类的工业控制系统。     

废气生物处理装置的远程监控系统

为有效控制污水处理设施的恶臭污染问题,设计了一种废气处理装置的监控系统;下位机采用西门子S7-300PLC,运用STEP7编程软件编制了现场PLC控制程序;上位机选用工控机,采用WinCC组态软件对上位机监控功能进行组态,实现现场数据实时记录和监控,并利用WinCC全局脚本开发了模糊自适应PID控制算法,实现了对生物滴滤池循环水pH值的模糊自适应PID控制;实际应用结果表明,该控制系统响应速度快、超调量小,大大改善了pH中和过程的控制效果.     

基于PLC与组态软件的热电厂循环水控制系统设计

针对热电厂循环水的处理问题,设计热电厂循环水自动加药计算机监控系统。本系统采用IPC和PLC组成的上下位机结构,上位机采用组态王6.52组态软件,主要承担监测和管理任务,实现工艺流程显示、人机交互界面、数据存储及报表等功能。下位机使用梯形图语言编程,进行实时数据采集和各种药品的投加控制。经过现场实际运行证明,该系统结构简单、操作方便、控制算法简单实用,取得了良好的经济效益。     

气动传送与分拣生产线控制系统的研究

设计了气动传送与分拣实训设备的控制系统,采用主从控制结构,计算机作为上位机,而PLC作为下位机,通过工业控制软件实现计算机与PLC的数据通信。利用工业控制软件和S7-300型PLC,实现了系统的监控和仿真,并设计系统的PLC程序,使系统各部分按预定的工艺流程工作,完成了工件传送与分拣任务。     

PLC与上位机监控系统的串行通讯实现

PLC与上位机监控系统的通讯技术是工业控制系统中的关键技术之一。以超薄快速铸轧板形控制系统为基础 ,在保证系统通讯安全可靠的前提下 ,设计了PLC与上位机监控系统最经济、可靠的通讯方案 ,采用功能强大的开发工具C Builder编制上位机通讯程序。该方案实现简单 ,通讯可靠 ,可移植性强 ,适合于同类的工业控制系统     

基于Delphi7.0的上位机与PLC的通信

本文介绍在将计算机与PLC结合起来,组成高性能价格比的小型集散控制系统―热电厂循环水过程控制系统中,在基于Delphi7.0上位机监控软件开发环境中如何实现上位机与S7-200系列PLC之间通信。     

基于PLC与力控的皮带运料虚拟监控系统设计

介绍了皮带运料系统PLC控制和力控组态软件设计过程,实现仿真现场工业控制要求。虚拟监控系统由上位机、通讯接口和下位机组成。上位机用力控组态软件制作虚拟监控界面,下位机下载PLC控制程序,通过通讯接口在上位机模拟皮带运料的运行情况。设计对工业现场的调试和研究有一定的参考价值。     

循环水自动加药系统的研究与设计

本文在对石化企业进行现场调研,对工业控制计算机、检测仪表及监控软件基本性能特点进行充分分析和研究基础上.设计与开发了基于工业组态软件组态王6.5的循环水自动加药系统.该系统由IPC610/PIII工控机和SIEMENS S7-300PLC以及检测仪表构成.上位机采用工业组态软件---KINGVIEW6.5设计.下位机用于数据采集和各种药品的投加控制.     

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.