21 results
Search Results
2. Over-excitation Relaying for Digital Generator Protection using the 765 kV Power System Modeling Data in Korea.
- Author
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Won, Park Chul and Hyeon, Ban Woo
- Subjects
ELECTRIC generators ,AIR conditioning ,ALGORITHMS ,DENSITY functionals ,SIMULATION methods & models ,ELECTRONIC excitation ,ELECTRIC power ,MATHEMATICAL models - Abstract
Abstract: A large AC generator is an important component of the power system. Researches on the AC generator relaying for the next-generation ECMS and an efficient operation of protection control system are necessary. These require developments on detailed generator modeling and internal fault analysis, and prototyping for multifunctional IED device dedicated to next-generation production. In this paper, over-excitation relaying algorithm is one of the main protection elements which have an important role in DGPS(Digital Generator Protection System), was proposed. This paper first briefly introduces a principles of over-excitation and DFT-based gain compensation algorithm was adopted for the frequency measurement. Subsequently, protection scheme of over-excitation was presented. The 765[kV] modeling data of South Korea using EMTP-RV was used for simulations. The simulation result of over-excitation relaying are also provided. [Copyright &y& Elsevier]
- Published
- 2012
- Full Text
- View/download PDF
3. Bidirectional Adaptations Workflow Management for the Route-choice Application.
- Author
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Yang, Lei and Cao, Yang
- Subjects
WORKFLOW ,ROUTE choice ,BIDIRECTIONAL associative memories (Computer science) ,ALGORITHMS ,INFORMATION processing ,MATHEMATICAL models - Abstract
Abstract: This paper tries to widen the notion of adaptation to take account of bidirectional adaptations between the context and activities so as to ensure not only the activity adaptation but also the adaptation of the context of the user to the requirements of the activities. What''s more, this paper presents a bidirectional adaptations workflow management algorithm (BAWM) for the route-choice of campus navigation, which can dynamically adjust workflow execution behaviors based on current context information and the user activities. This paper also manages to show that the correctness of the BAWM algorithm by formulating it as a Petri-net model. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
4. A kind of user behavior authentication model and analysis in cloud computing.
- Author
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Tian, Li-Qin, Lin, Chuang, Yang, Ni, and Duxiujuan
- Subjects
COMPUTER access control ,MATHEMATICAL models ,CLOUD computing ,COMPUTER security ,COMPUTER software ,ALGORITHMS ,INTERNET users ,PETRI nets - Abstract
Abstract: Currently, the cloud computing is welcome in scholars and enterprise, because of its good features such as low investment, easy maintenance, Flexibility and fast deployment, reliable service. However, when the cloud computing is implemented, the security and credibility is one of the biggest obstacles. In cloud computing, users directly use and operate software of cloud service providers, operating system, even programming environment and network infrastructure, so the impact and breakage users caused for cloud software and hardware resources more serious than the current Internet users to share resources. So whether the behavior and behavior subject is credible or not, how to authenticate and control user behavior, these are important parts of the cloud computing study. This paper presents the concept of user behavior authentication, discusses how to authenticate and control user behavior in the cloud computing environment according to the user''s behavior, include establishment of behavior authentication set, mechanisms of behavior authentication and control, corresponding mode of Stochastic Petri Nets, False Negative rates and algorithm performance etc. Paper lays the theoretical and practical foundation for the real application of cloud computing. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
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5. Ear Recognition based on Gabor Features.
- Author
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Yuan, Li, Mu, Zhichun, and Zeng, Hui
- Subjects
GABOR transforms ,FEATURE extraction ,DIGITAL image processing ,ALGORITHMS ,MATHEMATICAL models ,DISCRIMINANT analysis ,KERNEL functions - Abstract
Abstract: In this paper, we propose an ear recognition system based on 2D ear images which includes three stages: ear enrollment, feature extraction and ear recognition. Ear enrollment includes ear detection and ear normalization. The ear detection approach based on Gentle Adaboost algorithm detects the ear part under complex background using two steps: off-line cascaded classifier training and on-line ear detection. Then Active Shape Model is applied to segment the ear part and normalize all the ear images to the same size. For its eminent characteristics in spatial local feature exaction and orientation selection, Gabor-based ear is presented in this paper. Kernel Fisher Discriminant Analysis is applied for dimension reduction of the high-dimensional Gabor features. Then distance based classifier is applied for ear recognition. The experimental results on USTB ear database show effectiveness of the proposed approach. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
6. An Empirical Analysis for the Dynamic Relationship between China's Energy Consumption and Economic Growth--Based on Cointegration Analysis and State-Space Model.
- Author
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Ying, Ma, bin, Wang, and Long, Xue
- Subjects
ENERGY consumption ,ECONOMIC development ,MATHEMATICAL models ,EMPIRICAL research ,COINTEGRATION ,KALMAN filtering ,ALGORITHMS - Abstract
Abstract: Distinguished from former literature which focuses on the static or balanced analysis, this paper established the timevarying parameters model based on state space model to find the dynamic relationship between China''s energy consumption and economic growth. After applying Chow test, unit root test and cointegration test, this paper estimated the parameters of state space model with Kalman Filter Algorithm, then found and analyzed their internal regularity. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
7. Modeling and Control of Multi-Terminal VSC HVDC Systems.
- Author
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Beerten, Jef and Belmans, Ronnie
- Subjects
HIGH-voltage direct current converters ,CONTROL theory (Engineering) ,MATHEMATICAL models ,SIMULATION methods & models ,VOLTAGE regulators ,ALGORITHMS - Abstract
Abstract: This paper discusses the modeling and control of Voltage Source Converter High Voltage Direct Current (VSC HVDC) systems in a multi-terminal configuration (MTDC). Both steady-state interactions, as well as transient stability modeling and control are addressed. Simulation results show that adequately modelling the DC voltage droop characteristics or a distributed voltage control in both the power flow algorithm and in the transient stability models allows to simulate the steady-state results of the dynamic simulation by means of power flow software algorithms. [Copyright &y& Elsevier]
- Published
- 2012
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8. The Comprehensive Evaluation of Smart Distribution Grid Based on Cloud Model.
- Author
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Li, Lingling, Liu, Lixin, Yang, Chunwen, and Li, Zhigang
- Subjects
SMART power grids ,CLOUD computing ,ELECTRIC power distribution ,MATHEMATICAL models ,DISTRIBUTION (Probability theory) ,ALGORITHMS - Abstract
Abstract: Smart distribution grid is an important part of smart grid. Cloud model is used in smart distribution grid; It can achieve mutual combination and conversion between the qualitative evaluation system and the quantitative study. The paper introduces the development status of the smart distribution grid and distribution grid, the numerical characteristics of cloud model and algorithm of synthesized cloud. By establishing the model of two-level index synthesized cloud and remarks cloud, the evaluation results can be given in the form of probability distribution. The example shows that the model of the evaluation results is intuitive and reliable; it has important significance in guiding practice. [Copyright &y& Elsevier]
- Published
- 2012
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9. Research on the Performance Evaluation of Chongqing Electric Power Supply Bureaus Based on TOPSIS.
- Author
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Huang, Wei and Huang, YanYan
- Subjects
PERFORMANCE evaluation ,ELECTRIC power ,MATHEMATICAL models ,ALGORITHMS ,ELECTRIC industries - Abstract
Abstract: It is difficult to evaluate the performance of the different companies feasibly and fairly only depending on experts. An evaluation model based on TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) is built to solve this problem. In this model, the method of data processing and the evaluation algorithms are analyzed detailed. By means of the evaluation model, eight electric power supply bureau of Chongqing are evaluated in this paper, and the results show feasibly and reasonably. [Copyright &y& Elsevier]
- Published
- 2012
- Full Text
- View/download PDF
10. Test System for Disaggregation Algorithms for use in Smart Meters.
- Author
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Benyoucef, Dirk, Bier, Thomas, and Klein, Philipp
- Subjects
TEST systems ,ELECTRIC meters ,ALGORITHMS ,MATHEMATICAL models ,ELECTRIC equipment ,DWELLINGS -- Electric equipment ,ELECTRIC power consumption ,ELECTRIC generators ,ELECTRIC potential - Abstract
Abstract: In this paper a test system for verifying disaggregation algorithms is presented. The main part of the test system is a test set generator. Based on the model of a real voltage source, the generator generates test sets. With these test sets the quality of the developed algorithms can be analyzed. These algorithms will be developed for the implementation in a smart meter. The smart meter system is used for the disaggregation of electrical appliances in residential buildings. This allows to be closed on energy consumption of the individual appliance. The development of a complete smart meter system is the goal of the research project “Smart Metering” at the University of Furtwangen. [Copyright &y& Elsevier]
- Published
- 2012
- Full Text
- View/download PDF
11. Islanding Detection Technique using Grid-Harmonic Parameters in the Photovoltaic System.
- Author
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Kim, Il-Song
- Subjects
PHOTOVOLTAIC power systems ,ELECTRIC power plants ,ELECTRIC inverters ,ALGORITHMS ,MATHEMATICAL models ,PERFORMANCE evaluation - Abstract
Abstract: Power Conditioning System (PCS) in the photovoltaic system requires reliable islanding detection function (passive or active) in order to know electrical grid status and operate the grid connected inverter properly. This paper proposes a passive islanding detection algorithm based on the grid harmonic components. It utilizes the fact that the equivalent harmonic components at the point of common coupling (PCC) are changed according to the grid connection status. This method shows reduced Non-Detection Zone (NDZ) and fast detection time compared to the conventional approach. The mathematical modeling is performed and verified by experimental result using high performance DSP controller [Copyright &y& Elsevier]
- Published
- 2012
- Full Text
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12. Load Balancing for Device Management Server.
- Author
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Zhou, Yi, Guo, Shaoyong, Rui, Lanlan, and Li, Wenjing
- Subjects
LOAD balancing (Computer networks) ,CLIENT/SERVER computing ,ALGORITHMS ,REACTION time ,PERFORMANCE evaluation ,MATHEMATICAL models - Abstract
Abstract: This paper introduces a solution, Device Management Load Balancing Solution (DMLBS) which includes system design and load balancing algorithm, to achieve load balancing on Device Management server. Our solution improves both user response time and throughput for a single Device Management server, while exposing one interface to clients. DMLBS achieves its performance by using dynamic adaptive load balancing strategy and designing a mathematic model to measure Device Management server load. With these means, compared to two well-known load balancing algorithms (LeastLoaded and Round-Robin), DMLBS provides outstanding performance on load balancing. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
13. A Fast Algorithm for TV − L1 Based on Split Bregman Method.
- Author
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Wang, Wenbin, Shen, Chaomin, Zhong, Chenying, and Zhang, Guixu
- Subjects
SPLIT Bregman method ,ALGORITHMS ,IMAGE denoising ,MATHEMATICAL models ,ANALYSIS of variance ,IMAGE processing - Abstract
Abstract: The Rudin-Osher-Fatemi (ROF) model is one of the best successful models for image denoising. Recently, the TV-L1 model, which replaces the L2-norm of the standard ROF model with the L1-norm, has been proposed. The L1-norm outperforms the L2-norm for some applications. However, because of the total variation (TV) norm and L1-norm, it is difficult to compute. In this paper, we propose a fast algorithm based on the Bregman / Split Bregman method to solve the TV-L1minimization problem, and show several examples to demonstrate its efficiencies. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
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14. Research on LOD Technology in Virtual Reality.
- Author
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Xin, Li
- Subjects
VIRTUAL reality ,ALGORITHMS ,REAL-time computing ,QUADTREES ,GRID computing ,MATHEMATICAL models - Abstract
Abstract: Through the research on the existing virtual reality and LOD technology, for the realization difficulties of LOD echnology, this paper presents an optimized algorithm for real-time building terrain multi-resolution model based on errain quadtree, this algorithm uses hierarchical block thinking, through which only one traverse of the quadtree the rid will be generated, thus the system overhead grid caused can be reduced and the rendering speed will be greatly mproved. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
15. A retrieval method of mechanical part based on ontology.
- Author
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Peng, Wang
- Subjects
COMPUTER-aided design ,PROBLEM solving ,ALGORITHMS ,IMAGE segmentation ,MATHEMATICAL models ,INFORMATION retrieval - Abstract
Abstract: To resolve the problems such as how to implement 3D CAD model retrieval and how to reuse the retrieval results, this paper descripes an ontology-based algorithm for mechanical part retrieval. The mechanical part is segmented into many relevant sub-parts. And then, attach semantic descriptions and annotations to these sub-parts. Finally, evaluate the similarity of the models based on the semantic ontology. This method can efficiently achieve the similarity assessment of the mechanical parts and as well reflect human perceptual similarity. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
16. Optimal Scheduling Scheme of Gas Pipeline Network Based on Improved Particle Swarm Algorithm.
- Author
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Wu, Liu, Xueqin, Gu, Yuan, Xu, and Junshan, Li
- Subjects
PRODUCTION scheduling ,NATURAL gas pipelines ,PARTICLE swarm optimization ,ALGORITHMS ,MATHEMATICAL models ,CHAOS theory ,NATURAL gas pipeline compressor stations - Abstract
Abstract: A mathematical model of optimal scheduling scheme for gas pipeline network is established, which takes maximum benefits of pipeline network service provider as objective function after comprehensively considered the resources of gas field, downstream gas utilizing conditions, operating parameters of compressor stations and work conditions of pipeline system etc. Evolutionary-based particle swarm algorithm has been investigated, and a new hybrid particle swarm algorithm with embedded chaotic search has been presented to the optimization solution of pipeline network scheduling. Improved algorithm makes use of the ergodicity of chaos to improve the capability of precise search and keep the balance between the global search and the local search, which is able to avoid the premature convergence problem effectively. This paper took a gas network with 17 nodes, 16 pipelines, 2 compressor stations as example, and make the decision on the optimal scheduling scheme for gas pipeline network. The analysis of example demonstrates the effectiveness and applicability of the established model and algorithm. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
17. Application of Blind Signal Separation in Speech Processing.
- Author
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Xiaomei, Yang
- Subjects
BLIND source separation ,SPEECH processing systems ,WIRELESS communications ,GEOGRAPHICAL discoveries ,IMAGE enhancement (Imaging systems) ,DIGITAL image processing ,ALGORITHMS ,SIGNAL-to-noise ratio ,MATHEMATICAL models - Abstract
Abstract: The blind signal separation which has many potential usage, especially in the respects of such as wireless communication, medical analysis, geographical exploration, and image enhancement and recognition is a developing basic research direction. This paper mainly studies the application of it in speech processing and proposes a mathematical description of the blind signal separation problem in including mathematical model for blind separation problem and basic assumptions to ensure the blind separation to be solvable. It focuses on the analysis of the blind signal separation based on instantaneous mixed mode. It also proposes speech blind signal separation algorithm based on instantaneous mixed circumstance and performs computer emulation and signal-to –noise-ration analysis to confirm the effectiveness of the algorithm. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
18. Study of Multi-domain Interoperability Authorization Algorithm based on RBAC.
- Author
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Xu, Lei and Sui, Xin
- Subjects
INTERNETWORKING ,ACCESS control of computer networks ,MATHEMATICAL models ,COMPUTER network security ,DATA mapping ,ALGORITHMS - Abstract
Abstract: To achieve inter-domains access authorization, role mapping relationships between different domains need to be established in multi-domain collaborative system based on RBAC. This paper introduces access control model achieving secure interoperation in multi-domains, through expanding and reconstructing access control policy. Policy and algorithm are proposed, which separated roles generated in the original model are released, including Static Release and Dynamic Release, in order that the original model can be applied in multi-domain access control system based on RBAC without time constraint. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
19. Slope Stability Evaluation by Cellular Ant Algorithm.
- Author
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Liyun, YI
- Subjects
SLOPE stability ,ALGORITHMS ,AUTOMATION ,MATHEMATICAL models - Abstract
Abstract: There are many factors involved in slope stability evaluation and the principle ones acts differently under different slope environmental conditions. So the evaluation of slope stability demands for consideration for all kinds of factors generally with clear understanding of primary and secondary factors. Based on the theory of ant algorithms and cellular automaton, this paper puts forward a cellular ant algorithm and mathematic description with MATLAB to optimize the accuracy of slope stability evaluation and verifies the applicability of the algorithm through real project and achieves good results. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
20. Classification Technology by Least Squares Support Vector Machine Trained by Chaos Particle Swarm Optimization.
- Author
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Li, Yanhong and Liu, Taihui
- Subjects
CLASSIFICATION ,LEAST squares ,SUPPORT vector machines ,PARTICLE swarm optimization ,ALGORITHMS ,MATHEMATICAL models - Abstract
Abstract: In the paper, least squares support vector machine trained by chaos particle swarm optimization (CPSO-LSSVM) is applied in the classification. Chaos particle swarm optimization algorithm is introduced to select the suitable training parameters of least squares support vector machine. That is because chaos particle swarm optimization algorithm can avoid being trapped in local optimum and gaining the global optimum quickly in the process of search by combining particle swarm optimization with chaos queues. The experimental results demonstrate that least squares support vector machine trained by chaos particle swarm optimization is best classification results in the three classification algorithms. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
21. From UML 2.0 Activity Diagram to YAWL: The Controlflow Aspect.
- Author
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Han, Zhaogang and Zhang, Li
- Subjects
MATHEMATICAL transformations ,MATHEMATICAL mappings ,MATHEMATICAL models ,BUSINESS models ,ALGORITHMS ,WORKFLOW - Abstract
Abstract: Model transformations are frequently applied in model-driven development to bridge between languages on a different level of abstraction and formality. In This paper, we define a transformation from UML 2.0 Activity diagram(UML-AD for short) to YAWL, a formal workflow language that is able to capture all of the 20 workflow patterns reported in. The transformation is mainly concerned on the control-flow aspects of UML-AD models. We illustrate the transformation challenges and present a suitable transformation algorithm. The benefit of the transformation is threefold. First, it clarifies the semantics of UML-AD via a mapping to YAWL. Second, the deployment of UML-AD business process models as workflows is simplified. Third, UML-AD models can be analyzed with YAWL verification tools. a [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
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