连铸结晶器拉坯阻力信号特征提取及识别

在板坯连铸生产过程中,为实现结晶器拉坯阻力信号的自动识别,采用小波包变换技术,对MDF信号进行降噪预处理,并提取结晶器在不同状态下的阻力信号特征。针对故障样本相对较少的情况,采用虚拟样本技术对其进行扩充,以实现样本的平衡性。最后,采用支持向量机方法,对提取的结晶器拉坯阻力信号特征进行识别研究。实验结果表明,采用小波包变换技术提取的阻力信号特征明显,支持向量机对提取的阻力特征识别精度高、实时性强。     

基于热电偶测温的漏钢预报系统

在结晶器铜板中埋入热电偶对铜板进行热监控,可以有效地检测和预报粘结漏钢。通过对影响漏钢预报系统预报准确率的原因进行分析,镭目公司开发了一种高准确率漏钢预报系统。多家钢厂采用RAMON漏钢预报系统后证明,该系统从判断漏钢到输出拉速信号的响应时间≤0．5S,漏钢检测的准确率≥95％,报警输出率≥99％。     

改进的最小二乘支持向量机在入侵检测系统中的应用

介绍最小二乘支持向量机的基本原理论．提出基于最小二乘支持向量机的网络入侵检测系统模型。由于计算经验风险的损失函数为二次函数形式．LSSVM丧失了标准支持向量机的稀疏性,为使LSSVM具有稀疏性,从统计分析的角度出发,应用主成分分析的方法,对样本集进行特征提取,消除变量间的相关性。选取训练样本中分类作用最大的若干样本个体作为支持向量,并将非支持向量上的分类信息转移至支持向量上．提出新的LSSVM稀疏化算法——基于主成分分析的最小二乘支持向量机算法。实验结果表明,由此构建的稀疏LSSVM分类器保持了支持向量机的良好分类性能．而稀疏率相对高,其支持向量数甚至少与标准支持向量机,明显提高了LSSVM的分类效率和实时性。     

不平衡样本下的金融市场极端风险预警研究

为了提高金融市场极端风险识别及预警能力,采用沪深300指数作为研究数据,通过少数类样本过采样算法（SMOTE）解决样本不均衡问题,利用因子分析提取特征,通过粒子群（PSO）优化的最小二乘支持向量机（LSSVM）算法构建（SMOTE-PSO-LSSVM）预测模型。使用SMOTE-PSO-LSSVM模型对2007-2010年沪深300指标样本进行预测,样本含极端风险样本193条,模型成功识别风险样本154条,识别准确率达到了83.1%。研究结果表明SMOTE-PSO-LSSVM模型对金融风险数据识别能力较强,能够较为精准地识别风险样本,且求解速度快运行效率高,比传统BP网络和支持向量机等方法性能更优秀。该研究结论对金融市场的风险识别、市场趋势把控、股市交易管制以及投资者决策具有一定意义。     

基于最小二乘支持向量机的网页主题语义分类的研究

提出了对网页主题进行语义扩展的方法,利用最小二乘支持向量机LSSVM（least squares support vector machines）来代替传统的支持向量机SVM（support vector machine）的分类技术。在建立LSSVM模型的多类别分类算法基础上,将其应用到网页主题语义分类。实验表明,最小二乘支持向量机学习速度快,在小样本情况下具有良好的非线性建模和泛化能力,对网页主题语义分类具有很好的效果。     

基于神经模糊技术的漏钢诊断预报模型的研究

剖析了连铸结晶器粘结性漏钢的基本特征,利用热电偶,提出一种的漏钢诊断预报模型。主要包括神经模糊判别技术,单偶神经网络判别技术,组偶神经网络判别技术,并用现场工艺数据进行了仿真。     

基于模糊神经网络的一种漏钢预报方法*

现有拉漏预报方法经常会发生误报，本文尝试了一种基于神经网络的漏钢预报方法，它采用神经网络进行模糊模式识别和预测拉漏事故，实验表明该方法能比原有方法更快速准确地检测出铸坯粘结和裂缝等缺陷，可有效预防连铸中的漏钢事故。     

基于小波神经网络的结晶器漏钢预报技术研究

介绍了预报粘结性漏钢的基本方法,并对结晶器热电偶测得的大量温度数据进行预处理,再利用小波神经网络技术对经过预处理的检测数据进行训练,优化神经网络系统的结构和参数,识别出具有漏钢征兆的波形,提高了预报系统的精度和快速性;给出了用MATLAB实现的网络训练和测试的仿真结果,同时用VC开发了能识别结晶器内单偶、横向、纵向漏钢征兆温度波形的仿真系统。     

连铸过程中几个关键环节的设计与实现

根据连铸生产实际需要,对该过程中的结晶器液位控制、漏钢预报以及铸坯冷却控制 等关键问题设计了一套智能化综合控制与监测系统.在连铸生产中使用表明,该系统快速而准 确,实时性能良好,便于实施,具有很高的实用价值.     

结晶器温度场可视化系统研究

漏钢是连铸生产过程中最严重的故障之一;目前,现有的漏钢预报系统大都是根据热电偶所采集的有限温度数据给出温度随时间变化的二维曲线,而无法使操作人员了解非采集点区域的温度情况;文章介绍了结晶器温度场可视化系统的组成和实现方法;主要实验参数有浇注温度、热流密度、热传导系数、比热容、冷却水流量、结晶器进出水温差、拉坯速度等;通过分析结晶器铜板的传热原理,建立温度热传导模型,确定其边界条件;通过与实测温度值相比较,证明了温度场模型的有效性;根据温度场模型的计算结果,用虚拟仪器工具LabVIEW和有限元分析软件ANSYS开发了结晶器温度场可视化系统,作为漏钢预报系统的辅助判断手段和决策平台。     

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.     

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.     

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.     

Call for Papers The 6^th International Conference on Grid and Cooperative Computing

Recent years have seen rapid advances in various grid-related technologies, middleware, and applications. The GCC conference has become one of the largest scientific events worldwide in grid and cooperative computing. The 6th international conference on grid and cooperative computing (GCC2007) Sponsored by China Computer Federation (CCF),Institute of Computing Technology, Chinese Academy of Sciences (ICT) and Xinjiang University ,and in Cooperation with IEEE Computer Soceity ,is to be held from August 16 to 18, 2007 in Urumchi, Xinjiang, China.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

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