广义离散随机线性系统的最优递推滤波方法(Ⅱ)

本文对文献[1]给出的广义离散随机线性系统最优估计误差协方差阵进行了分析,在一定 条件下得到了误差协方差阵的上界和下界,继而讨论了由文献[1]给出的滤波器的稳定性.     

协方差矩阵加权波束形成及应用

在逆波束形成方法的基础上提出一种改进的协方差矩阵加权波束形成方法，它根据阵元的分布情况对阵元接收信号的协方差矩阵进行直接加权，使得环境噪声相关比较强的协方差元素得到抑制，环境噪声相关性比较弱的部分被加强，降低噪声增益，从而达到提高阵增益的目的。文中给出了两种协方差加权方法。并且计算了在各向均匀噪声环境下的阵增益。从阵增益和误差稳定性两个方面与CBF和MVDR方法进行了对比，验证了该方法的正确性。     

一种改进的光流算法

光流法是运动图像序列分析的一种重要方法。该文通过引入前向－后向光流方程，计算其Hessian矩阵，把Hessian矩阵条件数的倒数作为Lucas－Kanade光流法的加权阵，可有效消除局部邻域中不可靠约束点，同时提高基本约束方程解的稳定性。实验表明该方法相对于其它梯度约束光流法具有更好的可靠性。     

双线性随机离散系统的协方差配置控制及设计

本文提出并讨论了一类双线性随机离散系统的协方差配置控制问题，给出了由状态反馈可配置的状态协方差的集合，以及能配置这些状态协方差的状态的反馈增益阵的集合，在状态方差受约束的情形下，本文给出了反馈控制器的设计步骤及数值例子。     

单通道阵列无失真空时二维谱估计算法

针对单通道阵列空时二雏谱估计问题,提出了一种处理单通道阵列采样信号的新方法.该方法构建了单通道阵列特有的含有通道切换时间与采样间隔的阵列流型矩阵与导向矢量；无需对原始采样信号进行预处理,使其直接应用于现有的谱估计算法.基于此信号处理方法,给出了单通道空时平面阵以及去冗余的空时L型阵无失真二雏谱估计算法,在同等条件下,两...     

一种混合源环境下的波达方向估计方法

提出了一种基于均匀线阵的混合源波达方向DOA估计的新方法。该方法首先利用传统MUSIC方法估计出非相干信号源的DOA,然后对整个阵列数据协方差矩阵进行差分消除不相关源信号和噪声的影响,再对此差分矩阵进行特殊的空间平滑去相干,利用重建的数据协方差矩阵估计相干源的DOA。此方法的特点是分别估计不相关信号和相干信号的DOA,优点是在可估计出多于阵元数信号的前提下具有较高的DOA估计精度和稳健性。理论分析和仿真结果表明此方法的估计性能优于空间差分平滑算法。     

关于不确定线性连续随机系统的协方差上下界研究*

在随机控制领域中，线性系统的鲁棒性质及性能指标常常以其稳态状态协方差矩阵的形式给出。本文研究在状态矩阵及噪声矩阵中均含有不确定性的线性连续随机系统的稳态状态协方差上下界确定问题，从而为基于协方差性能指标的控制与模型简化提供必要的理论分析基础。     

一类不确定线性系统鲁棒状态估计器设计

本文对一类不确定线性系统给出了一种鲁棒状态估计器设计方法，其主要思想是对允许的系统扰动，通过设计估计器参数矩阵使增广系统的极点位于左半复平面指定圆形区内或指定直线的左侧，且稳态误差协方差阵不超过给定上限，给出了鲁棒估计器存在条件及其解的一般表达式。     

测量误差协方差矩阵的鲁棒估计

由于经典的误差协方差阵间接估计方法对于过失误差存在非常敏感,本文提出了一种基于Hampel三截尾估计的间接估计方法,在无过失误差和存在过失误差的情况下都能给出测量误差协方差矩阵可靠的估计,两个仿真实例表明了算法的鲁棒性。     

相关信道下MIMO系统误符号率的研究

研究在基于发射相关信道的MIMO系统中,采用线性ZF接收机时各子数据流信噪比的概率分布;利用随机矩阵理论,推导了信噪比概率密度函数公式;给出了采用MPSK调制时,各子数据流误符号率的闭式公式;在发射端采用均匀线阵条件下,分析了角度扩展对误符号率的影响。     

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