• Journal of Electrical Engineering and Technology
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• v.6 no.2
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• pp.245-254
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• 2011

This paper presents a new group for multilevel converter that operates as symmetric and asymmetric state. The proposed multilevel converter generates DC voltage levels similar to other topologies with less number of semiconductor switches. It results in the reduction of the number of switches, losses, installation area, and converter cost. To verify the voltage injection capabilities of the proposed inverter, the proposed topology is used in dynamic voltage restorer (DVR) to restore load voltage. The operation and performance of the proposed multilevel converters are verified by simulation using SIMULINK/MATLAB and experimental results.

• Journal of Chest Surgery
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• v.24 no.4
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• pp.382-389
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• 1991

The clinical observations on the 63 cases of the mitral valvular heart disease treated in the department of Thoracic and Cardiovascular Surgery, Kosin medical college, during the period of 5 years from January, 1986 to December, 1989, are as follows. 1. Total 63 cases, 23 were male and 40 were female with sex ratio of 1: 1.7. 2. The age distribution was widely varied from 7 years of the youngest to 65 years oldest, average age was 35.3 year old. 3. The main clinical symptom and sign were D.O.E, general weakness, fatigability, palpitation, chest pain, hepatomegaly, pitting edema and both neck vein distension. 4. The preoperative N.Y.H.A functional classification were class II, III, IV in 28%, 54%, 16%. 5. The preoperative diagnosis were MS - 6.3%, MR - 53.9%, MSR - 36.5%, MVP - 3.1%. 6. All 63 patients were operated on the under direct vision using extracorporeal circulation, MVR in 18 cases, MVR and Tricuspid annuloplasty in 24 cases, DVR in 3 cases, DVR and Tricuspid annuloplasty in 5 cases, TVR in 1 case, Mitral annuloplasty in 4 cases, mitral valvuloplasty in 7 cases and mitral commissurotomy in 2 cases 7. The operative mortality was 7.9%, and 5 years actuarial survival rate was 89%.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.901_902
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• 2009

This paper describes the development of a three-phase Line-Interactive DVR(Dynamic Voltage Restorer), which is applied to Hybrid detection method and super-capacitor. The operational feasibility was verified through computer simulations with PSCAD/EMTDC software, and experimental will be work with 3kVA prototype. The developed system can compensates the input voltage sag and interruption within 2ms, in which the maximum allowable sensitive load, such as computer, communication equipment, automation equipment, and medical equipment. The developed system has a simple structure to be easily implemented with commercially available components and to be highly reliable in operation.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.4
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• pp.203-209
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• 2002

This paper presents a new control scheme for a DVR(Dynamic Voltage Restorer) system consisting of series voltage source PWM converters. To control negative sequence component of source voltage the detection of negative sequence is necessary. Generally, filtering process is used tn do that. Through this filtering process has some problems. This paper suggests a new method of separating positive and negative sequences. This control system is designed using differential controllers and digital filters, and positive sequence and negative sequences are controlled respectively. The performance of the presented controller and scheme are confirmed through simulation and actual experiment by 2.5kVA prototype DVR.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.11
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• pp.1947-1954
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• 2007

This paper describes the development of a high-performance single-phase line-interactive Dynamic voltage Restorer, which is composed of an H-bridge inverter and super-capacitors. The operational feasibility was verified through computer simulations with PSCAD/EMTDC software, and experimental works with 3kVA prototype. The developed system can compensates the input voltage sag and interruption within 2ms, in which the maximum allowable duration of voltage interruption is 1.5 seconds. It can be effectively used to compensate the voltage interruption in the sensitive load, such as computer, communication equipment, automation equipment, and medical equipment. The developed system has a simple structure to be easily implemented with commercially available components and to be highly reliable in operation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.10
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• pp.1954-1961
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• 2009

This paper describes the development of a three-phase line-interactive dynamic voltage restorer with hybrid detection method, which is composed of three H-bridge inverter modules and super-capacitors. The operational feasibility was verified through computer simulations with PSCAD/EMTDC software, and experimental works with a 3kVA prototype. The developed system can compensate the input voltage sag and interruption within 2ms. The maximum allowable duration of voltage interruption is about 4 seconds. The developed system can be effectively used to compensate the voltage interruption in the sensitive load, such as computer, communication devices, and automation devices, and medical equipment. The developed system has a simple structure to be easily implemented with commercially available components, and to be highly reliable in operation.

• Journal of the Korea Computer Graphics Society
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• v.27 no.5
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• pp.25-32
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• 2021

Direct Volume Rendering(DVR) renders by projecting data into a two-dimensional space without calculating the volume surfaces. In DVR, the transfer function(TF) assigns light properties such as color and transparency to the volume. However, it takes a long time for beginners to manipulate TF to understand volume data and assign colors. This paper proposes an approach to colorize the volume using sample images for intuitive volume rendering. We also discuss color extraction methods using K-means clustering.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.5
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• pp.755-760
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• 2023

In this paper, the 2.4/5GHz dual band was used to ensure the reliability and stability of the wireless AV surveillance system using the existing 2.4GHz band. The proposed system supports dynamic channel allocation and channel change technology to avoid interference from other signals (Wifi, Bluetooth, etc.), reduces maintenance costs incurred when building wireless CCTV, and can be linked with existing wired CCTV. The service area of the A/V surveillance system used can be expanded.

• The Journal of the Acoustical Society of Korea
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• v.28 no.2
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• pp.112-118
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• 2009

This paper proposes a rapid detection algorithm of a salient region for music video browsing system, which can be applied to mobile device and digital video recorder (DVR). The input music video is decomposed into the music and video tracks. For the music track, the music highlight including musical chorus is detected based on structure analysis using energy-based peak position detection. Using the emotional models generated by SVM-AdaBoost learning algorithm, the music signal of the music videos is classified into one of the predefined emotional classes of the music automatically. For the video track, the face scene including the singer or actor/actress is detected based on a boosted cascade of simple features. Finally, the salient region is generated based on the alignment of boundaries of the music highlight and the visual face scene. First, the users select their favorite music videos from various music videos in the mobile devices or DVR with the information of a music video's emotion and thereafter they can browse the salient region with a length of 30-seconds using the proposed algorithm quickly. A mean opinion score (MOS) test with a database of 200 music videos is conducted to compare the detected salient region with the predefined manual part. The MOS test results show that the detected salient region using the proposed method performed much better than the predefined manual part without audiovisual processing.

• Journal of Chest Surgery
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• v.25 no.1
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• pp.57-65
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• 1992

St.Jude Medical cardiac valve replacement was performed in 322 patients: 191 had mitral, 58 had aortic, 72 had double valve and 3 had tricuspid valve replacement. Motality rate in early period was 2.8%[9 patients]. The most common cause of early death was low cardic output syndrome. Follow up extended from 1 to 90 months[mean: 34 months] in 292 patients among 313 in all surviving patients [93.6%]. There were thrombolic complications in eighteen patients. The probability of free from thromboembolism at 5 yerars in MVR, AVR and DVR were 84.7%, 91.8% and 90.2% respectively. And also, actuarial event free rate at 5 years in MVR, AVR and DVR were 80.1%, 82.2%, and 81.4% respectively. There were fourteen late death during follow up period: six from thromboembolism, one from hemorrhage and the others from non valve related -or unknown complications. The acturial survival rate at 5 years were 93.1% in mitral, 92.1% in aortic and 97.1% in double valve replacement. In conclusion, the performance of the St. Jude Mecanical valve compares most favorably with other artificial valves. But it remains still hazards of mechanical prosthesis such as thromboembolism and anticoagulant related hemorrhage.