基于振动信号和云推理的球磨机负荷软测量

采用振动信号对球磨机料位进行测量时,特征值具有散度大、随机性强的特点.对此,基于具有将随机性、模糊性与稳定倾向性相结合能力的云模型,提出一种利用云模型对球磨机料位进行概念表示和推理测量的方法.首先,利用逆向云发生器对振动信号的功率谱特征值进行概念提取以获得前件云;然后,由料位值信息建立相对应的后件云;最后,利用云模型的不确定推理实现球磨机料位的软测量.对比实验结果表明了所提出方法的有效性和可行性.     

融合改进蚁狮算法和T-S模糊模型的噪声非线性系统辨识

针对传统的T-S模糊辨识方法难以准确辨识含噪声的非线性系统问题,将噪声信号和系统的其他输入变量一起作为模糊前件的输入,采用具有动态随机搜索和寻优半径连续收缩机制的改进蚁狮算法优化模糊前件的结构参数,使用加权最小二乘法实现模糊后件的参数辨识.数值仿真表明,所提出的辨识方法可以有效抑制噪声的影响,经过改进蚁狮算法优化后的T-S模糊模型辨识效果更好.最后,将所提出方法用于直拉硅单晶生长热模型的辨识,实验结果表明该方法优于传统的辨识方法.     

基于CART-LSSVM的球磨机料位软测量方法研究

球磨机是用于电力、磨矿和冶金等行业的高能耗设备,准确测量其滚筒料位能够提高运行效率和安全性能.针对其滚筒内料位难以实时检测,球磨机的轴承振动信号中存在较多的冗余特征,提出了一种基于分类回归树和最小二乘支持向量机的软测量方法,首先用Welch法获得振动信号的功率谱密度,并分割得到基本特征,然后建立分类回归树模型,根据最优树模型的分支节点进行特征选择,最后利用最小二乘支持向量机实现特征变量与料位间的非线性映射.通过实验结果的对比分析,验证了该模型的有效性和实用性,以及良好的预测精度.     

基于改进T-S模型的航空发动机振动值监控方法

针对T-S模型在规则库建立过程中存在的重复学习、效率低下等问题,采用模糊关联规则挖掘的方法对T-S模型进行改进;首先采用基于矩阵的模糊关联规则挖掘算法,深入分析和利用频繁项集的性质,减少数据库扫描次数以及挖掘过程中产生的中间结果,提高规则挖掘效率;其次,从挖掘结果中选取模糊规则,对其处理后建立T-S模型规则库;最后,将改进的T-S模型应用于航空发动机振动值监控中;实验结果表明,改进的T-S模型能够有效实现发动机振动监控。     

基于振动信号频谱分析的球磨机料位监测仪表的设计

有效测量球磨机料位，是制粉系统实现自动控制、运行优化、节能降耗的关键。提出用分裂基FFT变换对球磨机轴承振动信号进行处理，得出振动的功率频谱与料位变化之间的关系；并依此设计出由DSP和MPU组成的双CPU智能仪表的软硬件系统，实现球磨机料位的在线测量显示和报警功能，为制粉系统优化和自动控制奠定了基础。     

基于DSP的电厂球磨机料位监测系统

介绍了电厂球磨机料位测量的运用现状,指出了现有球磨机料位测量方法存在的问题,提出了一种以轴承振动能量法为基础,基于DSP的电厂球磨机料位实时监测系统的实现方法,具体阐述了系统原理结构,硬件设计和软件结构.     

基于软测量的球磨机优化控制方法

针对球磨机控制的难点和不足,提出了一种基于料位软测量技术的球磨机优化控制方法.首先,在分析球磨机系统特性和振动特性的基础上,确定了料位软测量的辅助变量.其次,基于最小二乘支持向量机算法,给出了一种球磨机料位软测量方法,并通过现场实测数据进行料位检测,结果表明该软测量方法的精度较高;最后,在料位软测量的基础上,提出了一种...     

基于支持向量机回归的T-S模糊模型自组织算法及应用

结合模糊聚类算法和支持向量机回归算法提出了一种新的T-S模糊模型自组织算法. 该算法首先利用一种改进模糊聚类算法提取模糊规则和辨识前件参数,然后将T-S模糊模型后件变换为标准线性支持向量机回归模型,并利用支持向量机回归算法辨识后件参数. 仿真结果表明,相比现有的自组织算法,本文提出的T-S模糊模型自组织算法在规则数较少的情况下,仍然具有较高的辨识精度和较好的泛化能力. 最后,利用提出的T-S模糊模型自组织算法较好地建立了直拉硅单晶炉加热器和空气预热器的温度模型.     

基于T-S模型的非线性系统模糊聚类辨识方法

提出一种基于T-S模型的非线性系统模糊聚类辨识方法,对T-S模糊模型的前提部分和结论部分进行分开辨识,既简化该模型的辨识步骤,又提高它的泛化能力,同时也解决了T-S模糊模型随辨识系统复杂程度提高而规则数增大的问题。对一个非线性系统辨识的仿真结果验证了这种模糊聚类辨识方法的有效性。     

振动信号在球磨机料位监测系统的运用研究

球磨机内煤的料位对于操作人员和控制系统来说是个封闭的系统，为了更为准确地反映球磨机的位，使球磨机的磨煤出力达到最大，采用振动信号对钢球磨煤机的料位进行监测，在数据采集和监测中运用自适应可变限幅的滤波方法，得到的振动基波曲线与磨煤机内的料位形成相吻合的对应关系，从而为整个控制系统的优化设计和投入提供了直接有效的依据。实践证明，球磨机料位监测系统的应用可获得良好的经济效益。     

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.     

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)

正~~     

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