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第25届中国控制与决策会议

作者： Cheng Zeng Shan Liang Yingying Su Yangsheng Li College of Automation Chongqing University Department of Mathematics Guiyang university Key Laboratory of Dependable Service Computing in Cyber Physical SocietyMinistry of Education Chongqing University Department of Electric and Electronic Information Engineering Chongqing University of Science and Technology

ISBN: (纸本)9781467355322

This paper derives a more accurate sampled-data model than the Yuz and Goodwin type model for nonlinear systems in the case of the relative degree two, and analyzes the sampling zero dynamics of the sampled-data model to show a condition which assures the stability of the sampling zero dynamics of the proposed model. It is a nature extension of Ishitobi et al.'s result from a single-input single-output (SISO) nonlinear systems to a multi-input multi-output (MIMO) nonlinear systems.

关键词： nonlinear systems, sampled-data models, zero dynamics, relative degree

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DSP based Fuzzy controller applied to a DC-DC Boost converter

DSP based Fuzzy controller applied to a DC-DC Boost converte...

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IEEE International Symposium on Intelligent Signal Processing

作者： João T. de Carvalho Neto Andrés O. Salazar Fábio M. U. de Araújo Anderson L. de O. Cavalcanti Department of Computing Engineering and Automation Federal University of Rio Grande do Norte Brazil

This paper presents a Fuzzy controller applied to a DC-DC Boost converter in order to minimize the system's power loss effects by adjusting the duty cycle of the converter. The variation in the input voltage and the losses in the electronic components of the converter (load variations) are the main causes of these power losses. The main objective of the controller is to maintain a constant voltage at the load regardless of these losses. The Fuzzy controller was embedded on a Digital Signal Processor in order to have a great reliability and a faster system response. The results show that the Fuzzy control technique can be utilized to minimize the effects of the system's uncertainties and disturbances while keeping the system's output response in its operating point.

关键词： Voltage control Load management Digital signal processing Mathematical model Fuzzy control Inductors Steady-state

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Operating limits of underexcited synchronous generator

Operating limits of underexcited synchronous generator

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International Conference on Power engineering, Energy and Electrical Drives, POWERENG

作者： Zlatko Maljković Ivan Gašparać Faculty of Electrical Engineering and Computing Department of Electrical Machines Drives and Automation University of Zagreb Zagreb Croatia

Standard power chart of synchronous generator has its limit defined by practical stability limit and by field current minimum in the underexcitation quadrant. However, during the time, some generators have shown certain sensitivity during the permanent underexcited operation even in the stabile operating area due to local heating of magnetic conductive parts in the end region of the machine. Underexcited operation is usually required in case of raised network voltage while the active power demands are lowered. Precise knowledge of limits of underexcited operation ability enables precise planning of system reactive power trading. Some world experiences and axial magnetic field measurements in the end region of synchronous hydro and turbine generator are presented. Based on mentioned measurements, it is possible to define real power chart which almost always deviates in capacitive operating area compared to manufacturer's diagram.

关键词： Generators Temperature measurement Probes Reactive power Stators Magnetic flux Vectors

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Multimedia stimuli databases usage patterns: a survey report

Multimedia stimuli databases usage patterns: a survey report

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Proceedings of the International Convention MIPRO

作者： M. Horvat S. Popović K. Cosić Faculty of Electrical Engineering and Computing Department of Electric Machines Drives and Automation University of Zagreb Zagreb Croatia

Multimedia documents such as images, sounds or videos can be used to elicit emotional responses in exposed human subjects. These stimuli are stored in affective multimedia databases and successfully used for a wide variety of research in affective computing, human-computer interaction and cognitive sciences. Affective multimedia databases are simple repositories of multimedia documents with annotated high-level semantics and affective content. Although important all affective multimedia databases have numerous deficiencies which impair their applicability. To establish a better understanding of how experts use affective multimedia databases an online survey was conducted into the subject. The survey results are statistically significant and indicate that contemporary databases lack stimuli with rich semantic and emotional content. 73.33% of survey participants find the databases lacking at least some important semantic or emotion content. Most of the participants consider stimuli descriptions to be inadequate. Overall, 1-2h or more than 24h are generally needed to construct a single stimulation sequence. Almost 84% of the survey participants would like to use real-life videos in their research. Experts unequivocally recognize the need for an intelligent stimuli retrieval application that would assist them in experimentation. Almost all experts agree such applications could be useful in their work.

关键词： Multimedia databases Multimedia communication Semantics Educational institutions Software tools Generators

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Steady-State Synchronous Machine Model which Incorporates Saturation and Cross-Magnetization Effects

Steady-State Synchronous Machine Model which Incorporates Sa...

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International Conference on Power engineering, Energy and Electrical Drives

作者： Zlatko Hanic Mario Vrazic Zlatko Maljkovic University of Zagreb Faculty of Electrical Engineering and Computing Department of Electric Machines Drives and Automation Zagreb Croatia

ISBN: (纸本)9781467363914

In this paper steady-state synchronous machine model which incorporates magnetic saturation and cross-magnetization is presented. Instead of using synchronous reactances and induced voltage Eo this model uses current dependent flux linkage functions in direct and quadrature axes to model armature reaction. If those functions are modeled as a polynomials of three independent variables which are armature current in direct and quadrature axis and field current, identification of the proposed model's parameters from load operation data becomes a linear problem. Paper also provides a method for calculation arbitrary steady-state load operation point based on the knowledge of the current dependent flux linkage functions. Proposed model, identification and calculation methods are validated and tested on 35 MVA, 10.5 kV, 50 Hz synchronous generator.

关键词： MVA synchronous generator Cross-Magnetization Effects

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Developing an optimized application hosting framework in Clouds

Developing an optimized application hosting framework in Clo...

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作者： Shi, Xuanhua Jiang, Hongbo He, Ligang Jin, Hai Wang, Chonggang Yu, Bo Chen, Xueguang Service Computing Technology and Systems Lab School of Computer Huazhong University of Science and Technology China Department of Electronics and Information Engineering Huazhong University of Science and Technology China Department of Computer Science University of Warwick United Kingdom InterDigital Communications Corp. United States Department of Automation Control and Engineering Huazhong University of Science and Technology China

A Cloud system, which is also often called a data center, may host a large number of application servers (termed as applications for short in this paper) that consume various types of resource, such as CPU, memory, and I/O. In such a scenario, the application placement strategy, which specifies how to host applications across the physical servers in the Cloud, is critical to achieve good system- and/or client-oriented performance. The existing application placement algorithms in literature assume that the consumption of system resources is proportional to the level of workloads submitted to the system. In this paper, we reveal that it may not be the case in some circumstances. Based on this observation, we design and implement an application placement framework, called EAPAC, for Clouds. The developed framework is able to achieve the optimized performance by judiciously allocating to the applications a proper mixture of different types of application request as well as an appropriate number of requests in each type. Further, we investigate the issue of resource conflicts among different applications when there exist concurrent requests in the system. We have conducted extensive experiments to evaluate the performance of the developed framework. The experiment results show that compared with the existing method in literature, EAPAC can improve the performance by 35% in terms of the reply rate. © 2013 Elsevier Inc.

关键词： Application placement Cloud Resource conflicts

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New LS-SVM approximate solutions to ordinary differential equations

New LS-SVM approximate solutions to ordinary differential eq...

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Chinese Control Conference (CCC)

作者： Guoshan Zhang Yiming Wang Shiwei Wang Wanquan Liu School of Electrical Engineering and Automation Tianjin University Tianjin China Department of Computing Curtin University WA Australia

ISBN: (纸本)9789881563835

In this paper a new method is proposed to solve morder linear and one order nonlinear ordinary differential equations (ODEs) based on Least Squares Support Vector Machines (LS-SVMs). At first, an appropriate transition is made from the ODEs to an optimization problem, after which the algorithm solves the optimization problem in the LS-SVM framework. Finally a high-accuracy differentiable approximate solution with simple and fixed structure is presented in closed form. Numerical results demonstrate the efficiency of the proposed method for solving non-stiff and singular ordinary differential equations with initial or boundary conditions.

关键词： Differential equations Electronic mail Least squares approximations Educational institutions Optimization Support vector machines Electrical engineering

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Sensor data quality assessment for building simulation model calibration based on automatic differentiation

Sensor data quality assessment for building simulation model...

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2013 IEEE International Conference on automation Science and engineering, CASE 2013

作者： Li, Sisi Song, Zhen Zhou, Mengchu Lu, Yan Department of Electrical and Computer Engineering New Jersey Institute of Technology Newark NJ 07013 United States Key Laboratory of Embedded System and Service Computing Ministry of Education Tongji University Shanghai 201804 China Department of Automation and Control Siemens Corporation Corporate Technology Princeton NJ 08540 United States

ISBN: (纸本)9781479915156

Building simulation models play a vital role in optimal building climate control, energy audit, fault detection and diagnosis, continuous commissioning, and planning. Real system parameters are often unknown or partially unknown and need to be identified through historical data, which are currently acquired by heuristically designed experiments. Without quality sensor data, model calibration is prone to fail, even if the calibration algorithm is appropriate. In this paper, we propose a Fisher-information-matrix (FIM)-based metric to examine the sensor data measurements and how their quality is related to the model calibration quality. It aims to provide quantitative guidance in the calibration cycle of a whole building model that takes as many variables as possible into consideration for the sake of accuracy. Our concerned model is based on well-known physical laws and tries to avoid simplification, thereby leading to a highly discontinuous system with model switches due to the seasonal or daily variation and other reasons. Such a model is implemented in the form of a software package. Hence, no explicit mathematical expression can be given. A key technical challenge is that the complexity of the model prohibits the analytical derivation of FIM, while the numeric calculation is sensitive to sensor noise and model switches. We, hence, propose to adopt an automatic differentiation method, which exploits the operator overload feature of object oriented programming language, for robust numerical FIM calculation. © 2013 IEEE.

关键词： Numerical methods

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A comparative analysis of dissimilarity measures for clustering categorical data

A comparative analysis of dissimilarity measures for cluster...

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2013 International Joint Conference on Neural Networks, IJCNN 2013

作者： Xavier, João C. Canuto, Anne M. P. Almeida, Noriedson D. Goncalves, Luiz M. G. Digital Metropolis Institute Federal University of Rio Grande Do Norte Natal RN Brazil Department of Informatics and Applied Mathematics Federal University of Rio Grande Do Norte Natal RN Brazil Computing and Automation Engineering Department Federal University of Rio Grande Do Norte Natal RN Brazil

ISBN: (纸本)9781467361293

Similarity and dissimilarity (distance) between objects is an important aspect that must be considered when clustering data. When clustering categorical data, for instance, these distance (similarity or dissimilarity) measures need to address properly the real particularities of categorical data. In this paper, we perform a comparative analysis with four different dissimilarity measures used as a distance metric for clustering categorical data. The first one is the Simple Matching Dissimilarity Measure (SMDM), which is one of the simplest and the most used metric for categorical attribute. The other two are context-based approaches (DIstance Learning in Categorical Attributes - DILCA and Domain Value Dissimilarity-DVD), and the last one is an extension of the SMDM, which is proposed in this paper. All four dissimilarities are applied as distance metrics in two well known clustering algorithms, k-means and agglomerative hierarchical clustering algorithms. In this analysis, we also use internal and external cluster validity measures, aiming to compare the effectiveness of all four distance measures in both clustering algorithms. © 2013 IEEE.

关键词： Clustering algorithms

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Insights into the zero dynamics of nonlinear sampled systems with splines

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ICIC Express Letters 2013年第12期7卷 3237-3244页

作者： Zeng, Cheng Liang, Shan Ishitobi, Mitsuaki Su, Yingying College of Automation Chongqing University No. 174 Shazhengjie Shapingba Chongqing 400044 China Department of Mathematics Guiyang University No. 103 Jianlongdong Road Guiyang 550005 China Key Laboratory of Dependable Service Computing in Cyber Physical Society Ministry of Education Chongqing University No. 174 Shazhengjie Shapingba Chongqing 400044 China Department of Mechanical Systems Engineering Kumamoto University 2-39-1 Kurokami Kumamoto 860-8555 Japan

Most real world systems operate usually in continuous time, but, in practice, to utilize them the signal must first be sampled through digital devices. In this paper, we show how a particular strategy can be used to approximate the system output and its derivatives in such a way that splines are used to generate the continuous-time input to the system. Moreover, a sampled-data model obtained has an advantage to the Yuz and Goodwin's model in the error analyses aspect, and the results presented also show how the sampling zero dynamics of the proposed model obtaind are expressed. © 2013 ISSN 1881-803X.

关键词： Continuous time systems

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