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Frequency dependent network equivalent based electromagnetic and electromechanical decoupled hybrid simulation

Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering 2012年第16期32卷 107-114页

作者： Zhang, Yi Wu, Wenchuan Zhang, Boming Gole, Aniruddha M. State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China Department of Electrical and Computer Engineering University of Manitoba Winnipeg R3T 5V6 Canada

Neither electromechanical transient stability analysis (TSA) program nor electromagnetic transient (EMT) programs can be used individually for the transient stability studies of the large scale AC/DC systems. This paper presented an electromagnetic and electromechanical hybrid simulation system, based on a frequency dependent network equivalent. Firstly, the framework and the main modules of the proposed hybrid simulation system were introduced. Secondly, the methods to calculate the equivalents of the electromagnetic side and the electromechanical side were introduced. The discussion on the difference between the traditional method and frequency dependent network equivalent (FDNE) and the flowchart of the hybrid simulation were also given. In the last part of the paper, AC system and AC-DC hybrid system are both used as examples to demonstrate the accuracy of the proposed hybrid simulation system's simulation results. © 2012 Chinese Society for Electrical Engineering.

关键词： Hybrid systems

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Period distribution analysis of some linear maps

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Communications in Nonlinear Science and Numerical Simulation 2012年第10期17卷 3848-3856页

作者： Fei Chen Xiaofeng Liao Kwok-wo Wong Qi Han Yang Li State Key Lab. of Power Transmission Equipment and System Security College of Computer Science Chongqing University Chongqing 400044 PR China Department of Electronic Engineering City University of Hong Kong Hong Kong PR China Department of Automatic Control and Systems Engineering The University of Sheffield UK

This paper discusses period properties of some linear maps which are employed in various applications such as image encryption, public key cryptography and watermarking. Conditions for the bijectiveness of such maps and the existence of a period are presented. Period structure is also given. Then, the recurrence equation theory is adopted to address the period distribution problem. Finally, a framework to solve the problem is proposed with a demonstration of its effectiveness and efficiency into some applications.

关键词： Linear map Period distribution Periodic orbit Dynamical system Cat map

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A new search strategy of radio fingerprint matching method in wireless sensor network

A new search strategy of radio fingerprint matching method i...

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1st International Conference on Robot, Vision and Signal Processing, RVSP 2011

作者： Li, Hongchun Zhao, Xiaoguang Tan, Min Institute of Automation Chinese Academy of Sciences State Key Lab. of Intelligent Control and Management of Complex Systems Beijing China

ISBN: (纸本)9780769545813

Radio fingerprint matching localization method promises high localization accuracy but requires extensive infrastructural effort and search operations. This paper proposes a new search strategy for radio fingerprint matching method, which sharply reduces search operations and shows little effect on localization accuracy. Indoor experiment is conducted to evaluate our method. © 2011 IEEE.

关键词： Wireless sensor networks

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Wide Area control Framework Design Considering Different Feedback Time Delays

Wide Area Control Framework Design Considering Different Fee...

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IEEE Power and Energy Society General Meeting

作者： Gang Chen Yuanzhang Sun Vaithianathan "Mani" Venkatasubramanian Lin Cheng Jin Lin Anjan Bose Weixing Zhao Cheng Lin State Key Lab. of Power Systems Dept. of Electrical Engineering Tsinghua University Beijing 100084 China School of Electrical Engineering and Computer Science Washington State University Pullman WA 99164-2752 USA Guizhou Electric Power Grid Dispatching and Control Center Guiyang Guizhou 550002 China

ISBN: (纸本)9781467327275

In this paper, a framework for a real-time wide area controller is established for damping small-signal instability related events in interconnected power systems. Offline designing is performed to design the centralized controller for each inter-area mode of the power system. Residue approach is used to select the most effective stabilizing signals and controller locations. Different constant time delays are taken into controller parameters design. Thus an offline controller database is formed, including different controllers of each mode. The parameters of each controller are different for various ranges of time delay. The damping and other mode information will be identified by online multi-Prony analysis. When an inter-area mode is detected with weak or negative damping, say less than 3%, the corresponding controller for the detected mode will be initiated and deployed for enhancing the damping of the problematic mode. The time delay, which is used to select a suitable set of parameters for a chosen controller, could be calculated online, using the time stamps of the actuator and feedback signal. The paper proposes the framework of the controller with preliminary discussions on the various components of the controller, including: 1) the offline controller database, 2) the online detection of undamped oscillations, and 3) the online corrective control actions at the actuator. The 4-machine 2-area case study results demonstrated the advantage of the proposed method.

关键词： Small signal stability phasor measurement units (PMUs) power system stabilizer (PSS) wide area control damping controller time delay controllers timestamp time delay undamped oscillations central controller OFF LINE Frameworks actuators

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Budget-constrained bidding in the sponsored search

Budget-constrained bidding in the sponsored search

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21st Workshop on Information Technologies and systems, WITS 2011

作者： Li, Xiarong Zeng, Daniel Dajun Yang, Yanwu State Key Lab. of Intelligent Control and Management of Complex Systems Chinese Academy of Sciences China Management Information Systems Department University of Arizona United States

In this paper, we study the budget-constrained bidding problems in sponsored search. Our findings illustrate that, compared to budget-irrespective bidding, advertisers can obtain equal even better return-on-investment... 详细信息

关键词： Budget control

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Budget allocation in competitive search advertisements

Budget allocation in competitive search advertisements

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21st Workshop on Information Technologies and systems, WITS 2011

作者： Yang, Yanwu Li, Juanjuan Zhang, Jie Zeng, Daniel State Key Lab. of Intelligent Control and Management of Complex Systems Chinese Academy of Sciences Beijing 100190 China Department of Management Information Systems University of Arizona United States

This paper proposes a novel budget model based on differential game to deal with budget allocation in competitive search advertisements under a finite time horizon, with consideration of budget constraints. We extend the advertising response function with the dynamical advertising effort u and quality score q to fit search advertising scenarios. We also discuss Nash equilibriums of our model, and study some desirable properties of two kinds of equilibriums in the case with budget constraints: "budget-stable" open-loop Nash equilibrium (BS-OLNE) and "budget-unstable" open-loop Nash equilibrium (BUS-OLNE). We have evaluated our budget model and identified properties with computational experiments. Experimental results show that budget strategies with dynamical advertising elasticity are superior to those with fixed one and our findings on OLNEs are helpful for advertisers to make budget decisions.

关键词： Marketing

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A comparison study of candidate generation for Chinese word segmentation

A comparison study of candidate generation for Chinese word ...

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7th International Conference on Natural Language Processing and Knowledge Engineering, NLP-KE 2011

作者： Zhang, Kaixu Sun, Maosong State Key Lab. of Intelligent Technology and Systems Department of Computer Science and Technology Tsinghua University Beijing 100084 China

ISBN: (纸本)9781612847283

Chinese word segmentation can be implemented in a coarse-to-fine schema. In such schema, a candidate set containing multiple segmentations of a sentence (rather than only one segmentation) is used as the output of a coarse-grained CWS model. Then a more sophisticated CWS model or other models of downstream tasks will reconsider all the segmentations in the candidate set to determine the best segmentation. This paper discussed and compared three candidate generation methods, namely boundary level method, word level method and sentence level method, in a unified form. The oracle F1-measures of the candidate sets of these methods were compared. The performances were also compared in a joint CWS and POS-tagging task. The results showed that the word level method has the best performance among these three candidate generation methods. Results also showed that the coarse-to-fine schema outperforms the pipeline schema in which only one segmentation is used for the downstream task and the joint schema in which all possible segmentation is used for the downstream task. Moreover, the speed of the coarse-to-fine schema is closed to the speed of the pipeline schema and much higher than the speed of the joint schema. © 2011 IEEE.

关键词： Pipelines

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Polarity shifting: Corpus construction and analysis

Polarity shifting: Corpus construction and analysis

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2011 International Conference on Asian Language Processing, IALP 2011

作者： Zhang, Xiaoqian Li, Shoushan Zhou, Guodong Zhao, Hongxia Natural Language Processing Lab. Soochow University Suzhou China State Key Laboratory of Intelligent Control and Management of Complex Systems Institute of Automation Chinese Academy of Sciences Beijing China

ISBN: (纸本)9780769545547

Polarity shifting has been a challenge to automatic sentiment classification. In this paper, we create a corpus which consists of polarity-shifted sentences in various kinds of product reviews. In the corpus, both the sentimental words and shifting trigger words are annotated. Furthermore, we analyze all the polarity shifted sentences and categorize them into five categories: opinion-itself, holder, target, time and hypothesis. Experimental study shows the agreement of annotation and the distribution of the five categories of polarity shifting. © 2011 IEEE.

关键词： corpus annotation polarity shifting sentiment classification

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MPC economic performance assessment based on equal-grid LQG benchmark

MPC economic performance assessment based on equal-grid LQG ...

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作者： Liu, Zhe Gu, Yong Xie, Lei State Key Lab. of Industrial Control Technology Institute of Cyber-Systems and Control Zhejiang University Hangzhou 310027 China

Model Predictive control technology as the most typical method of Advanced Process control has been developed rapidly and applied widely in process industry. Weather MPC controllers operate well or not affect the enterprise benefit directly, therefore it is significant to carry out economic performance assessment and optimization. As a pragmatic method, LQG benchmark introduces manipulated variables together with controlled variables into quadratic dynamic index, which is more suitable for industrial application than Minimum Variance control benchmark. However, traditional LQG benchmark is regressed from an unbalanced distribution of discrete points set, which causes unnecessary calculation and poor regression in more important parts of points set. To avoid this, the relationship between manipulated variables variance and controlled variables variance was calculated, an equal-grid LQG benchmark was introduced and added in two layers MPC optimization problem as an equation constraint, then the optimal MPC setting values or reference trajectory could be obtained. The economic performance assessment and simulation results for delayed coking furnace show the effect of proposed methods. © 2011 Zhejiang University.

关键词： Model predictive control

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A simple word trigger method for social tag suggestion

A simple word trigger method for social tag suggestion

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Conference on Empirical Methods in Natural Language Processing, EMNLP 2011

作者： Liu, Zhiyuan Chen, Xinxiong Sun, Maosong Department of Computer Science and Technology State Key Lab. on Intelligent Technology and Systems Beijing 100084 China National Lab. for Information Science and Technology Tsinghua University Beijing 100084 China

ISBN: (纸本)1937284115

It is popular for users in Web 2.0 era to freely annotate online resources with tags. To ease the annotation process, it has been great interest in automatic tag suggestion. We propose a method to suggest tags according to the text description of a resource. By considering both the description and tags of a given resource as summaries to the resource written in two languages, we adopt word alignment models in statistical machine translation to bridge their vocabulary gap. Based on the translation probabilities between the words in descriptions and the tags estimated on a large set of description-tags pairs, we build a word trigger method (WTM) to suggest tags according to the words in a resource description. Experiments on real world datasets show that WTM is effective and robust compared with other methods. Moreover, WTM is relatively simple and efficient, which is practical for Web applications. © 2011 Association for Computational Linguistics.

关键词： Social networking (online)

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