基于机器人的神经网络预测控制算法

针对预测控制机理在处理非线性模型控制存在较大的困难,提出了将BP神经网络和广义预测控制(GPC)相结合后应用于网络控制系统的思想,构造了神经网络预测控制算法,其实质是用BP神经网络作为预测模型,产生预测信号,对系统进行反馈校正,并通过误差迭代求取广义预测的最优控制律,从而克服了对非线性系统难以辨识模型的困难,利用神经网络"黑箱"的功能达到对非线性系统的预测控制.以机器人为控制对象进行仿真,取得了较好的控制效果.     

并联混合神经网络模型及应用研究

单一神经网络难以对复杂模型做出准确的预测,提出了一种并联型混合神经网络模型用于对复杂的系统进行预测,该模型由径向基函数网络、BP网络和控制模块组成。控制模块用于线性映射层,将两种单一神经网络的输出结合并得到最终的输出结果。详细地给出了混合模型的预测方法：首先,利用改进算法分别训练径向基函数网络和BP网络;其次,采用自适应遗传算法优化线性映射层以获得更好的预测精度;最后,利用两个实例比较单一神经网络和提出的混合网络的预测性能。实验表明,混合神经网络在预测精度上比单一网络具有更优的性能,同时,该混合模型为复杂系统提供了一种通用的预测工具。     

基于机器人的神经网络预测控制算法

针对预测控制机理在处理非线性模型控制存在较大的困难,提出了将BP神经网络和广义预测控制（GPC）相结合后应用于网络控制系统的思想,构造了神经网络预测控制算法,其实质是用BP神经网络作为预测模型,产生预测信号,对系统进行反馈校正,并通过误差迭代求取广义预测的最优控制律,从而克服了对非线性系统难以辨识模型的困难,利用神经网络“黑箱”的功能达到对非线性系统的预测控制。以机器人为控制对象进行仿真,取得了较好的控制效果。     

基于混合模型的网络流量预测算法

研究网络流量准确预测,针对网络优化控制问题,由于网络数据拥塞严重,网络流量变化具有高度自相似性、非线性和多尺度等特点,线性数据的传统预测方法无法准确刻画网络流量的非线性变化规律,导致预测准确率低.为了提高网络流量的预测准确率,在分析网络流量变化特征的基础上,提出一种小波分析的网络流量混合预测模型.混合模型首先利用小波分析将网络流量分解线性和非线性部分,然后分别采用ARIMA模型和BP神经网络模型对其进行预测,最后采用小波分析对线性和非线性部分预测结果进行重构,得到混合模型最终预测结果.仿真结果表明,混合模型比其它网络流量预测模型具有更高的预测准确率,为网络优化控制提供了有效分析方法.     

BP神经网络模型预测控制算法的仿真研究

为克服被控对象参数变化导致控制精度降低的问题,研究了一种BP神经网络模型预测控制算法。借助最小二乘递推算法在线预测系统模型参数,利用BP神经网络在线预测PID参数以控制被控对象。该算法基于模型预测,首先在线性系统中验证其控制效果,然后将非线性问题作线性处理,采用BP神经网络模型预测PID控制器予以实现控制非线性系统。仿真曲线显示BP神经网络PID控制器用于线性系统可达到高精度控制要求;对于非线性系统有自适应及逼近任意函数的能力。仿真研究表明,该算法与传统BP神经网络PID控制器相比,其自适应能力更强,稳定性更好,控制精度更高。     

基于遗传优化的RBF-BP网络的实时故障检测

针对单一神经网络对复杂模型难以实时做出准确预测和BP神经网络自身的缺陷,结合RBF神经网络可以逼近任意函数的特性,提出了基于遗传优化的混合神经网络模型(RBF-BP)。由RBF网络和BP网络并联作为一个神经网络(简称为RBF-BP)的隐层,利用该网络对被控对象进行逼近训练、实时故障检测,该算法同时具有RBF网络和BP网络的优点,适用于复杂非线性系统的故障检测。     

神经网络广义预测控制在锅炉燃烧系统中的应用

针对锅炉燃烧系统的非线性、大延迟、时变、干扰频繁等特点,以煤粉浓度为中间被调量,将神经网络、广义预测控制、串级控制相结合,设计了基于神经网络模型的广义预测串级控制系统.该控制方法克服了单纯PID控制对大惯性大延迟对象调节品质差、抗干扰性弱的缺点,神经网络预测器有效地补偿了传统预测控制基于线性模型的局限性.将该控制算法用于燃烧系统中主汽压力对象的控制,仿真结果表明该方法具有较强的跟踪性能和抗干扰能力及良好的动静态性能指标.     

股票价格预测的建模与仿真研究

研究股票价格准确预测问题,由于股票价格数据具非线性、随机性等变化规律,同时股票市场与国内外经济政治变化有关,传统股票价格预测方法只能对其线性变化规律进行准确预测,无法反映股票价格非线性部分进行有效建模,导致股价预测精度不高。为了提高股票价格预测精度,提出了一种遗传优化BP神经网络的股票价格预测模型。充分利用BP神经网络良好的非线性映射能力,对股票价格变化规律进行建模,并通过遗传算法对BP神经网络模型参数进行优化,从而获最优股票价格最优预测模型。实验结果表明,相对于传统股票价格预测模型,遗传算法优化BP神经网络的股票价格预测模型拟合程度更好,预测精度更高,为股票价格预测提供了依据。     

基于PSO算法的WNN大包线增益调参控制律设计

提出了一种基于粒子群优化算法的小波神经网络大包线调参控制律设计方法.该方法用小波函数代替了Sigmoid函数作为激活函数.由于结合了小波变换良好的高频域时间精度、低频域频率精度的性质和神经网络的自学习功能,因而具有较强逼近非线性函数的能力.为了克服局部极小值问题并进一步提高对非线性函数逼近能力,利用粒子群优化算法对小波神经网络进行参数训练,并利用该网络实现了大包线增益调参.飞行仿真结果表明,所设计的小波神经网络增益调参控制器具有优良的控制性能,不仅能够保证平衡状态下的控制效果,而且在未训练的平衡状态下依然具有良好的控制性能,并且在存在20%的建模误差时,最大超调量仅为6 m,仅是使用常规增益调参方法的18%.     

基于核方法的移动机器人远程控制时延预测与分析*

构建了基于Internet的移动机器人控制平台,针对该平台中网络时延的非线性特性,提出了利用线性核和RBF核方法对网络时延序列样本进行回归建模和预测。比较了核方法、BP神经网络和RBF神经网络算法预测误差,表明在移动机器人远程控制中,核方法对网络时延序列预测具有更好的函数逼近能力和较高的预测精度,从而可根据预测时延调节移动机器人控制指令和状态信息的网络传输,保证系统的可靠性,提高移动机器人的控制性能。     

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)

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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