检索结果-内蒙古大学图书馆

2nd International Workshop on Digital Watermarking, IWDW 2003

作者： Hu, Yongjian Huang, Jiwu Kwong, Sam Chan, Y.K. School of Information Science and Technology Sun Yat-Sen University Guangzhou510275 China Department of Automatic Control Engineering South China University of Technology Guangzhou510641 China Department of Computer Science City University of Hong Kong Kowloon Hong Kong

ISBN: (纸本)354021061X

Digital watermarking has been researched extensively due to its potential use for data security and copyright protection. Much of the literature has focused on developing invisible watermarking algorithms. However, not much has been done on visible watermarking. A visible watermark is apparently needed for copyright notification. This work proposes a new framework of visible watermarking based on image fusion, a common technique used in combining images acquired from different modalities. To better protect the host features and increase the robustness of the watermark, the dual-tree complex wavelet transform (DT-CWT) is used. A new classification strategy is proposed to classify complex wavelet coefficients into 6 classes with different perceptual significance. The embedding decision can be made based on the classification information. Small watermark coefficients are prohibited from embedding. In the host edges, the insertion of watermark energy is controlled by using the inversely proportional embedding scheme to better preserve the sensitive region, while in other regions, the embedding strength becomes stronger as texture activity increases. This work also addresses the problem of low-pass subband watermark embedding, which is a special issue of visible watermarking. Experimental results show that the proposed algorithm yields significantly superior image quality than the current DCT-based method. © Springer-Verlag Berlin Heidelberg 2004.

关键词： Image watermarking

来源：评论

学校读者我要写书评

暂无评论

Optimal Decisions on Complex Infrastructure Systems

引用

IFAC Proceedings Volumes 2004年第19期37卷 139-143页

作者： Abdelaziz Nakrachi D. Popescu I. Matei USTL Polytech’Lille France University “Politehnica” of Bucharest Department of Automatic Control and Computer Science 313 Splaiul Independentei 060041 Bucharest 6 ROMANIA

This paper proposes the software package SISCON, dedicated to the evaluation of optimal decisions for large scale systems. SISCON firstly evaluates mathematical models developed from experimental data using LS methods for linear and nonlinear systems and after that computes the optimal decision problems, solving the mathematical non-linear programming problems. The large scale systems have generally a complex structure and global approach computation cannot be carried out. The authors present a decentralised decision structure having a well-defined distribution of supervisory functions. After decomposition of large – scale problems is carried out, sub problems are solved using standard optimization techniques. SISCON offers opportunities for solving non-linear mathematical programming problems and for evaluating optimal decisions in large scale systems control.

关键词： Optimisation problem large scale systems least square algorithm non-linear programming

来源：评论

学校读者我要写书评

暂无评论

A11: Measurement system for data acquisition and electric arc furnace characteristic calculation

引用

IFAC Proceedings Volumes 2004年第20期37卷 64-69页

作者： Robert Kazala Miroslaw Wcislik Kielce University of Technology Faculty of Electrical Engineering Automatic Control and Computer Science Al. 1000-lecia PP7 25-314 Kielce Poland

The paper presents the requirements of measurement system for electric arc furnace parameters measurement and for working characteristic calculating. On this basis measurement signals were specified and measurement algorithms were developed. For data acquisition a special system was constructed. The system consists of portable computer with acquisition card and conditioning system with differential amplifiers, antialiasing filters and sample and hold circuits. The system is connected with interface build-up permanent in arc furnace. The system software makes possible on-line observation of measured signals values and save data to hard disk. Further calculations may be performed off-line using special developed algorithms. For system software development the open source Python language and GCC compiler for Windows were used.

关键词： arc furnace data acquisition control system hardware algorithms

来源：评论

学校读者我要写书评

暂无评论

Iterative learning control - What is it all about?

Iterative learning control - What is it all about?

引用

2004 IFAC Workshop on Adaptation and Learning in control and Signal Processing, ALCOSP 2004 and IFAC Workshop on Periodic control Systems, PSYCO 2004

作者： Hätönen, J. Harte, T.J. Owens, D.H. Ratcliffe, J. Lewin, P. Rogers, E. Department of Automatic Control and Systems Engineering University of Sheffield Mappin Street SheffieldS1 3JD United Kingdom Department of Electronics and Computer Science University of Southampton SouthamptonSO17 1BJ United Kingdom

The main objective of this paper is to show how one can benefit from using Iterative Learning control instead of conventional feedback control. As a main result it is shown that even if the nominal plant satisfies a given uncertainty condition, there always exists ILC algorithms that can drive the tracking error monotonically to zero. This same result cannot be achieved with conventional feedback control, or by inverting a nominal model of the plant. Hence ILC offers an unique tool to invert dynamical systems with uncertainty. Copyright © 2004 IFAC

关键词： Robust control

来源：评论

学校读者我要写书评

暂无评论

Discrete-time Arimoto ILC-algorithm revisited

Discrete-time Arimoto ILC-algorithm revisited

引用

2004 IFAC Workshop on Adaptation and Learning in control and Signal Processing, ALCOSP 2004 and IFAC Workshop on Periodic control Systems, PSYCO 2004

This paper revisits the Arimoto-algorithm in the discrete-time case. It is shown that if a plant satisfies a positivity condition, there always exists a learning gain so that the algorithm converges monotonically to zero tracking error. If the plant does not satisfy the positivity condition, a linear LQ tracker can be used to condition the plant so that it satisfies the positivity condition. the overall structure results in a novel combination of Arimoto ILC and LQ optimal control, that drives the tracking error monotonically to zero for an arbitrary discrete-time LTI plant. This is a very strong property for any ILC algorithm. Copyright © 2004 IFAC

关键词： Iterative methods

来源：评论

学校读者我要写书评

暂无评论

Practical application of control theory to Web services

Practical application of control theory to Web services

引用

American control Conference (ACC)

作者： T. Abdelzaher Ying Lu Ronghua Zhang D. Henriksson Department of Computer Science University of Virginia Charlottesville VA USA Department of Automatic Control Lund Institute of Technology Lund Sweden

This tutorial describes experiences with applying a control theoretical approach to achieving performance guarantees in Web servers, with emphasis on delay control. A model for the server is formulated and translated into a control problem formulation. Limitations of the control theoretic approach is identified that arise due to system non-linearities and modeling inaccuracies. Solutions are proposed that augment the feedback control framework with elements of scheduling and queueing theory. The theoretical results and QoS control loops presented by the authors are implemented in a middleware package, called controlWare, which provides the software mechanisms and interfaces that allow control of real server performance. Implementation and performance of controlWare is described.

关键词： control theory Web services Web server Delay Feedback control Queueing analysis Middleware Software packages Packaging Software performance

来源：评论

学校读者我要写书评

暂无评论

Improved prediction for Web server delay control

Improved prediction for Web server delay control

引用

Euromicro Conference on Real-Time Systems

作者： D. Henriksson Ying Lu T. Abdelzaher Department of Automatic Control Lund Institute of Technology Lund Sweden Department of Computer Science University of Virginia Charlottesville VA USA

control methods are being used increasingly for uncertainty management and QoS in modern Web server systems. Previous approaches have suggested combined feedforward and feedback control strategies, using queuing theory for feedforward delay prediction. While queuing theory allows one to predict delay as a function of arrival and service rates, the prediction applies only to long-term averages, and is therefore insensitive to sudden load changes. Unfortunately, Internet load is very bursty, leaving room for predictor improvement. The main contribution of this paper is an extension of the combined feedforward/feedback framework in which the queuing model is replaced with a predictor that instead uses instantaneous measurements to predict future delays. The proposed strategy is evaluated in simulation and by experiments on an Apache Web server. It is shown that the approach performs better than the combined queuing model based feedforward and feedback control presented in earlier papers.

关键词： Web server Delay Feedforward systems control systems Feedback control Queueing analysis Uncertainty automatic control Internet Predictive models

来源：评论

学校读者我要写书评

暂无评论

Predictive motion control of a mirosot mobile robot

Predictive motion control of a mirosot mobile robot

引用

Proceedings of the Biannual World Automation Congress

作者： Jian Wan C.G. Quintero Ningsu Luo J. Vehi Department of Electronics Computer Science and Automatic Control University of Girona Girona Spain Universitat de Girona Girona Catalunya ES

This paper discusses predictive motion control of a MiRoSoT robot. The dynamic model of the robot is deduced by taking into account the whole process - robot, vision, control and transmission systems. Based on the obtained dynamic model, an integrated predictive control algorithm is proposed to position precisely with either stationary or moving obstacle avoidance. This objective is achieved automatically by introducing distant constraints into the open-loop optimization of control inputs. Simulation results demonstrate the feasibility of such control strategy for the deduced dynamic model

关键词： Motion control Mobile robots Robotics and automation automatic control Open loop systems Robot vision systems control system synthesis Robot control Predictive models Predictive control

来源：评论

学校读者我要写书评

暂无评论

Integrating phrases to enhance HSOMART-based document clustering

Integrating phrases to enhance HSOMART-based document cluste...

引用

International Joint Conference on Neural Networks (IJCNN)

作者： M.F. Hussin M.S. Kamel Department of Computer Science & Automatic Control Alexandria University Alexandria Egypt Department of Systems Design Engineering University of Waterloo Waterloo ONT Canada

Document clustering is one of the popular techniques that assist users in organizing collections of documents. Two successful models of unsupervised neural networks, self-organizing map (SOM) and adaptive resonance theory (ART), have shown promising results in this task. Most of the existing neural network based document clustering techniques rely on a "bag of words" document representation. Each word in the document is considered as a separate feature, ignoring the word order. We investigate the use of phrases rather than words as document features applied to our proposed document clustering technique, called hierarchical SOMART (HSOMART), which is a hierarchical network built up from independent SOM and ART neural networks. We describe a phrase grammar extraction technique, and the proposed HSOMART. The experimental results of clustering documents from the REUTERS corpus using the extracted phrases as features show an improvement in the clustering performance evaluated using the entropy and F-measure.

关键词： Neural networks Clustering algorithms Subspace constraints Tree graphs Text categorization computer science automatic control Organizing Resonance Feature extraction

来源：评论

学校读者我要写书评

暂无评论

Local receding horizon control with contractive constraints

Local receding horizon control with contractive constraints

引用

Proceedings of the Biannual World Automation Congress

作者： Jian Wan J. Vehl Ningsu Luo Department of Electronies Campus Montilivi Girona Spain Department of Electronics Computer Science and Automatic Control University of Cirona Campus Montilivi 17071 Giruna Spain

A novel local receding horizon control with contractive constraints is proposed in this paper. The main feature of the proposed control algorithm is to form open-loop optimizations in MPC locally. Thus the length of control horizons can be set relatively small, which is favorable for real-time applications. Moreover, the total and contractive coefficients in the proposed algorithm correspond to the prediction and control horizons in traditional MPC and they can be adjusted accordingly with clearer physical insights.

关键词： Open loop systems automatic control Stability control systems Constraint optimization computer science Industrial control Infinite horizon Optimal control Karhunen-Loeve transforms

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：