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You searched for subject:(Asymmetric SVM). Showing records 1 – 2 of 2 total matches.

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NSYSU

1. Chen, Huei-Yang. Automatic Detection of the Asymmetric Intervals of EEG by Using the Correlation Analysis of Amplitudes.

Degree: Master, Computer Science and Engineering, 2017, NSYSU

The electroencephalography is a common and valuable tool for research and diagnosis, especially when millisecond-range temporal resolution is required. EEG is usually used to diagnose epilepsy and other diseases of brain. This method has low cost and non-invasive advantages, and contains a lot of information. However, the electrodes are attached on the scalp directly, so the impact of the environment is obvious. Moreover, the EEG recordings contain more than 20 channels in a test and each test records for at least 30 minutes. The EEG can reï¬ect the signs of physical conditions in every minute so the neurologists will spend a lot of time and spirit for the interpretation of the EEG recordings. There will easily be errors and omission in the interpretation. Therefore, we focus on a condition which the neurologists will pay attention to in the interpretation of EEG recordings. That is about the brain symmetry problem because our body is balanced and in the symmetrical state. If we have asymmetric situation in the brain, it means that we have the possibility of the functional abnormalities. Therefore, in this thesis, we propose two methods to determine the interval of asymmetry. The ï¬rst one is the Amplitude Diï¬erence Ratio Method (ADR), and we are based on the ratio of the amplitude between left and right hemisphere. We divide the total area under the waveforms of left and that of right hemisphere as the ratio of asymmetry. If the degree of the diï¬erence is over a threshold which we set, this interval will be marked as an asymmetry interval. Basically, our methods focus on the frontal channels of the brain to be analyze, because the front of the channels are more sensitive to the electrode positions. Otherwise, due to the EEG is usually impacted by the environment, there are peak waveforms occurred as the false abnormal cases. Therefore, we deï¬ne the size of intervals as 5 seconds which is the non-short interval while computing. It can ï¬lter out the short period of waveforms and conï¬rm that the neurologists believe that abnormal activities are persistent behavior. However, the physicians does not only consider the amplitude, but also consider the frequency, waveforms, and other speciï¬c cases for interpreting the asymmetry. If we only consider the amplitude, we could not handle all of asymmetry cases. Therefore, our second method uses the Support Vector Machine with 3 Features (SVM3F) for learning, and considers three factors: the ratio of amplitude, the ratio of root mean square and the frontal asymmetry index. We can make the computer automatically learning to detect the intervals of asymmetry. Finally, we compare our results with the physicianâs observation. Although we cannot handle all cases, we have some suggestions. The larger the number of training data is, or the representative features have, the better accuracy of the results is. Advisors/Committee Members: Gen-Huey Chen (chair), Chih-Cheng Huang (chair), Ye-In Chang (committee member), Chun-I Fan (chair), Chien-I Lee (chair).

Subjects/Keywords: SVM; Frontal Asymmetry; EEG; Detection; Asymmetric Intervals

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Chen, H. (2017). Automatic Detection of the Asymmetric Intervals of EEG by Using the Correlation Analysis of Amplitudes. (Thesis). NSYSU. Retrieved from http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0518117-170526

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Chen, Huei-Yang. “Automatic Detection of the Asymmetric Intervals of EEG by Using the Correlation Analysis of Amplitudes.” 2017. Thesis, NSYSU. Accessed March 20, 2019. http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0518117-170526.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Chen, Huei-Yang. “Automatic Detection of the Asymmetric Intervals of EEG by Using the Correlation Analysis of Amplitudes.” 2017. Web. 20 Mar 2019.

Vancouver:

Chen H. Automatic Detection of the Asymmetric Intervals of EEG by Using the Correlation Analysis of Amplitudes. [Internet] [Thesis]. NSYSU; 2017. [cited 2019 Mar 20]. Available from: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0518117-170526.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Chen H. Automatic Detection of the Asymmetric Intervals of EEG by Using the Correlation Analysis of Amplitudes. [Thesis]. NSYSU; 2017. Available from: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0518117-170526

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


Virginia Tech

2. Zhang, Di. Analysis and Design of Paralleled Three-Phase Voltage Source Converters with Interleaving.

Degree: PhD, Electrical and Computer Engineering, 2010, Virginia Tech

Three-phase voltage source converters(VSCs) have become the converter of choice in many ac medium and high power applications due to their many advantages, including low harmonics, high power factor, and high efficiency. Modular VSCs have also been a popular choice as building blocks to achieve even higher power, primarily through converter paralleling. In addition to high power ratings, paralleling converters can also provide system redundancy through the so-called (N+1) configuration for improved availability, as well as allow easy implementation of converter power management. Interleaving can further improve the benefit of paralleling VSCs by reducing system harmonic currents, which potentially can increase system power density. There are many challenges to implement interleaving in paralleled VSCs system due to the complicated relationships in a three-phase power converter system. In addition, to maximize the benefit of interleaving, current knowledge of symmetric interleaving is not enough. More insightful understanding of this PWM technology is necessary before implement interleaving in a real paralleled VSCs system. In this dissertation, a systematic methodology to analyze and design a paralleled three-phase voltage source converters with interleaving is developed. All the analysis and proposed control methods are investigated with the goal of maximizing the benefit of interleaving based on system requirement. The dissertation is divided into five sections. Firstly, a complete analysis studying the impact of interleaving on harmonic currents in ac and dc side passive components for paralleled VSCs is presented. The analysis performed considers the effects of modulation index, pulse-width-modulation (PWM) schemes, interleaving angle and displacement angle. Based on the analysis the method to optimize interleaving angle is proposed. Secondly, the control methods for the common mode (CM) circulating current of paralleled three-phase VSCs with discontinuous space-vector modulation (DPWM) and interleaving are proposed. With the control methods, DPWM and interleaving, which is a desirable combination, but not considered possible, can be implemented together. In addition, the total flux of integrated inter-phase inductor to limit circulating current can be minimized. Thirdly, a 15 kW three phase ac-dc rectifier is built with SiC devices. With the technologies presented in this dissertation, the specific power density can be pushed more than 2kW/lb. Fourthly, the converter system with low switching frequency is studied. Special issues such as beat phenomenon and system unbalance due to non-triplen carrier ratio is explained and solved by control methods. Other than that, an improved asymmetric space vector modulation is proposed, which can significantly reduce output current total harmonic distortion (THD) for single and interleaved VSCs system. Finally, the method to protect a system with paralleled VSCs under the occurrence of internal faults is studied. After the internal fault is detected and isolated,… Advisors/Committee Members: Centeno, Virgilio A. (committee member), Leech, Irene E. (committee member), De La Ree Lopez, Jaime (committee member), Boroyevich, Dushan (committeecochair), Wang, Fei Fred (committeecochair).

Subjects/Keywords: passive component minimization; high power density; Asymmetric interleaving angle; harmonic current reduction; Asymmetric SVM; Interleaving; THD reduction; failure mode analysis

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Zhang, D. (2010). Analysis and Design of Paralleled Three-Phase Voltage Source Converters with Interleaving. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/27579

Chicago Manual of Style (16th Edition):

Zhang, Di. “Analysis and Design of Paralleled Three-Phase Voltage Source Converters with Interleaving.” 2010. Doctoral Dissertation, Virginia Tech. Accessed March 20, 2019. http://hdl.handle.net/10919/27579.

MLA Handbook (7th Edition):

Zhang, Di. “Analysis and Design of Paralleled Three-Phase Voltage Source Converters with Interleaving.” 2010. Web. 20 Mar 2019.

Vancouver:

Zhang D. Analysis and Design of Paralleled Three-Phase Voltage Source Converters with Interleaving. [Internet] [Doctoral dissertation]. Virginia Tech; 2010. [cited 2019 Mar 20]. Available from: http://hdl.handle.net/10919/27579.

Council of Science Editors:

Zhang D. Analysis and Design of Paralleled Three-Phase Voltage Source Converters with Interleaving. [Doctoral Dissertation]. Virginia Tech; 2010. Available from: http://hdl.handle.net/10919/27579

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