The DCT-based oscillation detection method for a single time series

This paper proposes a new method based on the discrete cosine transform (DCT), named as the DCT-based method, to detect oscillations for a single time series. The main idea is to isolate different frequency components of the time series via the DCT, and to detect oscillations by checking the regularity of zero-crossings of these isolated components. This method has the following features: (i) usage of only time series information of process variables without additional process knowledge, (ii) ability to deal with slowly varying trends, (iii) robustness to both white and colored noises, (iv) capability to handle the presence of multiple oscillations, and (v) amenability to complete automation without human intervention. Simulation examples and industrial case studies are presented to demonstrate the effectiveness and the above features of the DCT-based method.     

Does stock repurchase declaration affect stock price? Differences between the electrics industry and other industries

This study is to discuss the impact of stock repurchase declaration and purpose of repurchase on the stock price in the backdrop of listed companies on Taiwan’s stock market. Event Study Method is employed to discuss stock price fluctuations while GARCH (Generalized Autoregressive Conditional Heteroscedasticity) is applied to estimate the Market Model regressive coefficients. The samples consisted of companies declaring first stock repurchase are selected from August 9, 2000 to December 31, 2005 with a precondition that all the companies shall be listed ones 150 days prior to declaration. The study results reveal that companies from other industries have considerably bigger average CAR than companies of the electrics industry before and after the declaration of stock repurchase. Companies with application purpose of “maintain stockholders’ equities and corporate credit” have considerably bigger average CAR than companies with application purpose of “transferring stocks to employees”. In industries other than electrics, companies with application purpose of “maintain stockholders’ equities and corporate credit” have bigger accumulated abnormal return response than companies with application purpose of “transferring stocks to employees”. In case of “maintain stockholders’ equities and corporate credit” as the application purpose of stock repurchase, companies from industries other than electrics have relatively higher average CAR response. The empirical study results can serve as a reference for the listed company management and to related academic studies.     

基于OPC和以太网的电梯群远程系统的开发

远程监控对电梯安全运行和故障维修具有重要意义。应用以太网、组态王软件、OPC对象链接和嵌入技术,开发了电梯群远程监控系统,实现了与监控中心的计算机控制系统的双向通信。该系统主要具有电梯系统实时监控、报警监测、数据分析和事件分析等功能,适用于各种办公楼和大型住宅小区监控,具有广阔的应用前景。     

集散控制系统网络结构的研究

为了提高集散控制系统通信的可靠性、稳定性、抗干扰性和可扩展性,降低集散控制系统通信的故障率,提出了一种基于工业以太网的网络通信方式,并验证了该通信网络的可行性。该网络是一种采用分布式、冗余式、立体式的多层次网络结构。此结构使网络的负荷均匀分配,降低了网络的故障率,并使集散控制系统的网络向开放化、信息化的方向发展。     

一种数据挖掘系统的设计与实现

设计并用C#编程语言实现了一个面向初学者的开放通用数据挖掘系统。系统框架明晰、接口规范,便于系统的扩展和完善。给从事数据挖掘研究和应用的初学者提供了一个良好学习平台。     

基于ATmega128的调光控制器方案设计

现有的模拟调光控制器大多采用拉杆、旋钮、开关等对模拟信号进行变换,控制精度不高,体积较大,且只能实现对灯具的通断控制。本文结合PC上位机、ATmega128单片机及AD7226芯片实现一种高精度的模拟调光控制器,通过上位机的调光控制软件可以对灯具实现多种灯光效果的变换。     

Exponential stability and exponential stabilization of singularly perturbed stochastic systems with time‐varying delay

In this paper, the problems of exponential stability and exponential stabilization for linear singularly perturbed stochastic systems with time‐varying delay are investigated. First, an appropriate Lyapunov functional is introduced to establish an improved delay‐dependent stability criterion. By applying free‐weighting matrix technique and by equivalently eliminating time‐varying delay through the idea of convex combination, a less conservative sufficient condition for exponential stability in mean square is obtained in terms of ε‐dependent linear matrix inequalities (LMIs). It is shown that if this set of LMIs for ε=0 are feasible then the system is exponentially stable in mean square for sufficiently small ε?0. Furthermore, it is shown that if a certain matrix variable in this set of LMIs is chosen to be a special form and the resulting LMIs are feasible for ε=0, then the system is ε‐uniformly exponentially stable for all sufficiently small ε?0. Based on the stability criteria, an ε‐independent state‐feedback controller that stabilizes the system for sufficiently small ε?0 is derived. Finally, numerical examples are presented, which show our results are effective and useful. Copyright © 2010 John Wiley & Sons, Ltd.     

辩论支持系统的设计与实现

本文阐述了辩论支持系统开发的背景和意义,介绍了基于J2EE的系统需求,分析了软件的结构和主要功能模块及所用的关键技术框架,并在J2EE平台上开发实现了系统。     

Configurable Middleware for Distributed Real-Time Systems with Aperiodic and Periodic Tasks

Different distributed real-time systems (DRS) must handle aperiodic and periodic events under diverse sets of requirements. While existing middleware such as Real-Time CORBA has shown promise as a platform for distributed systems with time constraints, it lacks flexible configuration mechanisms needed to manage end-to-end timing easily for a wide range of different DRS with both aperiodic and periodic events. The primary contribution of this work is the design, implementation, and performance evaluation of the first configurable component middleware services for admission control and load balancing of aperiodic and periodic event handling in DRS. Empirical results demonstrate the need for, and the effectiveness of, our configurable component middleware approach in supporting different applications with aperiodic and periodic events, and providing a flexible software platform for DRS with end-to-end timing constraints.     

Fast k-nearest neighbor search algorithm based on pyramid structure of wavelet transform and its application to texture classification

Traditional fast k-nearest neighbor search algorithms based on pyramid structures need either many extra memories or long search time. This paper proposes a fast k-nearest neighbor search algorithm based on the wavelet transform, which exploits the important information hiding in the transform coefficients to reduce the computational complexity. The study indicates that the Haar wavelet transform brings two kinds of important pyramids. Two elimination criteria derived from the transform coefficients are used to reject those impossible candidates. Experimental results on texture classification verify the effectiveness of the proposed algorithm.