• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.118-120
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• 2020

양극성 DC 배전 시스템에는 높은 전압과 낮은 전압을 가진 두 양극성 버스가 사용된다. 두 양극성 버스간의 양방향 전력제어를 위해 DAB 컨버터가 사용된다. 또한, 양극성 DC 버스에는 두 극성에 균등한 전력 흐름이 형성되지 않기 때문에 이를 해결하는 전압 벨런서가 각각의 양극성 DC 버스마다 필요하다. 따라서 양극성 DC 배전 시스템을 구동하기 위해서는 총 3개의 전력변환장치가 필요하고 다수의 장치로 인해 전력밀도와 전력변환효율이 낮아지게 된다. 이러한 문제를 해결하기 위해 복수의 양극성 DC 버스 전압을 벨런싱하고 양방향 전력제어도 가능한 새로운 구조의 DAB 컨버터를 제안한다. 기존의 3단 구조와 달리 전력변환단계를 하나로 줄일 수 있어 전력밀도와 전력변환효율이 상승하게 된다. 제안하는 DAB 컨버터는 입력과 출력에 인덕터를 사용하여 입력과 출력에 접속되는 두 양극성 DC 버스 전압의 벨런싱을 가능하게 한다. 3-kW급 프로토타입을 통해 제안한 컨버터의 성능을 검증한다.

• Science of Emotion and Sensibility
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• v.21 no.2
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• pp.145-158
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• 2018

The purpose of this study was to investigate the visuo-spatial attention ability and the emotional perception ability of people across the normal range of the scores on the bipolar disorder scale. The Korean version of the Mood Disorder Questionnaire (K-MDQ) was used to measure the bipolar disorder tendency of normal people. A useful field of view (UFOV) task and an emotional perception task were used to measure visuo-spatial attention and emotional perception ability, respectively. The participants did not have any mental illness history or other medical problems. The participants were divided into three groups according to K-MDQ score (low, normal, and high), and their performances were compared. In the UFOV task, the high K-MDQ score group had lower level of performance than the other groups, suggesting that a high bipolar tendency is associated with reduction of visuo-spatial attention ability. In the emotional perception task, the group with the high K-MDQ score showed higher perception of negative emotion bias than the other groups, suggesting a high bipolar tendency to associate with reduction of emotional perception ability. These results suggest that visuo-spatial and emotional attention abilities are related with bipolar disorder tendency even in the normal population.

• Proceedings of the KIPE Conference
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• 2019.11a
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• pp.49-51
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• 2019

본 논문은 고전압 양극성 펄스 모듈레이터에 대해 소개한다. 모듈레이터는 충전을 위한 공진형 컨버터와 고전압 펄스를 생성하기 위한 12개의 파워셀로 구성된다. 12개의 파워셀은 다중 권선 변압기를 통해 모든 셀이 병렬로 충전되며, 방전 시에는 모든 셀이 직렬로 연결되어 고전압을 생성한다. 12개의 파워셀을 구성하는 48개의 스위치에 절연된 전력과 신호를 동시에 공급하기 위해, 2개의 고전압 케이블로 구성된 양극성 컨트롤 루프가 설계되었다. 최종적으로 10kV, 100A, 3kHz 사양을 갖는 양극성 펄스 모듈레이터가 구현되었으며, 저항부하 및 리액터 부하조건에서 테스트 되었다. 실험결과를 통해 제안하는 양극성 펄스 모듈레이터의 신뢰성이 검증되었다.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.254-256
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• 2019

본 논문은 파워셀 구조를 기반으로 설계된 양극성 펄스 전원장치에 대하여 소개한다. 파워셀은 풀브릿지 구조를 기반으로 설계되었으며, 833V를 출력하는 각 셀이 직렬로 연결되어 고전압을 생성하는 구조를 갖는다. 모든 파워셀의 방전 스위치를 구동하기 위해서 절연된 전력과 신호의 동시공급이 가능한 게이트 회로 구동방안이 제안되었다. 양극성 펄스 출력을 위한 파워셀의 각 래그의 단락을 방지하기 위한 게이트 회로가 설계되었다. 설계된 양극성 펄스 파워 모듈레이터의 동작을 검증하기 위해 테스트 회로가 구현되었다. 시험회로는 출력전압, 펄스 폭, 반복률 가변 조건에서 테스트 되었으며, 이를 통해 제안하는 양극성 펄스 파워 모듈레이터의 구조 및 게이트 구동회로의 신뢰성이 검증되었다.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.3
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• pp.355-362
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• 2011

In this paper, we developed the equipment to forming the insulation film which there are operated an electrolysis principles in particular solution. In the earlier, there are supplied the anode by unipolar voltage with pulse, in this paper, there are supplied the anode by bipolar voltage with pulse, alternately. And then, we examinate the system that there are developed the bipolar anodizing equipment using H-bridge. There are modulated pulse width for the variable current. In the results, we obtained the results of the uniform film surface that compared with the unipolar anodizing.

• Korean Journal of Psychosomatic Medicine
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• v.18 no.1
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• pp.19-29
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• 2010

Objectives：Authors hypothesized that bipolar tendency of non-psychiatric person would be associated with stress vulnerability. To test the hypothesis, we compared perceived stress level, Type A Behavioral Pattern (TABP) and unhealthy lifestyle between person with and without bipolar tendency. Methods：The study cohort consisted of 1987 subjects without past and current psychiatric history. In this study, bipolar tendency was determined by MDQ response which requires endorsement of at least 7 of the 13 "yes or no" questions. We compared the scores of Perceived Stress Scale, A/B lifestyle questionnaire, and unhealthy lifestyle(alcohol, smoking, lack of exercise, irregular meal) between MDQ positive and negative respondents. Results：We identified the bipolar tendency group determined by the MDQ positive response were 329 subjects(16.6%). The overall score of the bipolar tendency group was significantly high on the A/B lifestyle questionnaire compared to the non-bipolar tendency group(125.4 vs. 115.9, p<0.001), and the rate of the subjects defined as TABP was also significantly high(41.3% vs. 30.1%, p<0.001). In comparison of subjectively perceived stress level, the bipolar tendency group was observed to be significantly higher than the non-bipolar tendency group (18.5% vs. 16.5%, p<0.001). The bipolar tendency group was significantly higher than the non-bipolar tendency group on the rate of answering：'irregular eating habit' (20.1% vs. 14.3%, p=0.002), '4-or-more-times alcohol intake per week' (29.8% vs. 16.5%, p<0.001), 'currently smoking' (41.9% vs. 23.0%, p<0.001), '2-or-less-times physical exercises per week' (63.2% vs. 55.1%, p=0.007). Conclusion：By clinical diagnosis, even a person who does not meet the criteria of bipolar disorder has a high risk of stress-related behavioral pattern, and perceived stress when possessing bipolar tendencies such as the (hypo) maniac tendency or affective instability. Such individual has significantly higher risk of having unhealthy life-style such as smoking, drinking, irregular eating habit and lack of exercise compared to non-bipolar tendency group. Since these risk factors lead to increase the risk of obesity, metabolic syndrome, diabetes, and cardiovascular diseases, the individual with the bipolar tendency requires a more effort to manage stress and to maintain healthy lifestyle.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.9
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• pp.1307-1312
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• 2013

In this paper, alkaline or acidic solution, in particular the principle of electrolysis to oxidize the metal surface to form a device isolation film is developed. In the past, mainly in the form of pulse voltage is applied to the anode only a unipolar method, but in this paper by using the H-bridge to the amount of the positive (+) voltage and the negative supply voltage, alternating voltage polarity devices were fabricated according to the characteristics of metal specimens with different electrical conditions to form an oxide film on the device was developed. Supply current variable was used for the PWM modulation, (+) and (-) polarity change of the H-bridge bipolar pulse voltage to supply the was that. As a result, a more uniform pores with unipolar film was formed.

• Korean Journal of Psychosomatic Medicine
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• v.22 no.2
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• pp.112-120
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• 2014

Objectives : The aim of this study is to evaluate the clinical characteristics of night eating syndrome(NES) in bipolar disorder outpatients. Methods : The 14 items of self-reported night eating questionnaire(NEQ) was administered to 84 bipolar patients in psychiatric outpatient clinic. We examined demographic and clinical characteristics, body mass index(BMI), subjective measures of mood, sleep, binge eating & weight-related quality of life using Beck's Depression Inventory (BDI), Pittsburgh Sleep Quality Index(PSQI), Binge Eating Scale(BES) and Korean version of Obesity-Related Quality of Life Scale(KOQoL), respectively. Results : The prevalence of night eating syndrome in bipolar outpatients was 14.3%(12 of 84). Comparisons between NES group and non-NES group revealed no significant differences in demographic characteristics, BMI and clinical status except economic status and comorbid medical illnesses. However, compared to non-NES, patients with NES was more likely to have binge eating pattern and poorer weight-related quality of life. Conclusions : This study is to be the first to describe the clinical correlates of night eaters in bipolar outpatients. Although there were few significant correlates of NES in bipolar outpatients, relatively high prevalence of NES suggest that clinicians should be aware to assess the patients with bipolar disorder on NES, regardless of obesity status of patients.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.48-50
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• 2018

본 논문은 광물 탐사용 25kW 양극성 펄스전원장치에 대해 기술한다. 고효율 LCC 공진형 컨버터와 풀 브리지 기반 바이폴라 펄스 스위칭부로 구성된 500V, 12.5A 단위 모듈을 설계한다. LCC 공진형 컨버터는 도전 손실을 줄이기 위해 사다리꼴 모양의 공진 전류를 갖도록 하고, 높은 전력 밀도를 달성하기 위해 변압기의 누설 인덕턴스를 공진 인덕턴스로 활용한다. 또한, 반복적인 짧은 펄스 기반으로 설계된 게이트 구동 회로는 DC에서 8kHz의 주파수 범위를 동작시키고 게이트 변압기의 사이즈를 줄이기 위해 제안된다. 개발된 양극성 펄스전원장치는 4개의 모듈이 직병렬로 결선되어 부하 조건에 따라 Grounded dipole mode (2kV, 12.5A) 또는 Loop mode (500V, 50A)로 동작한다. 네 모듈의 출력 전압 밸런싱을 충족시키기 위해 LCC 공진형 컨버터의 변압기에 보상권선이 감긴다. 본 논문에서는 양극성 펄스전원 장치의 상세설계에 대해 기술하고, 시뮬레이션 및 실험 결과를 통해 이를 검증한다.

• Journal of the Korean Magnetics Society
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• v.18 no.2
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• pp.79-83
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• 2008

We have investigated the effect of the formation of an initial oxide layer on the fabrication of the porous aluminium oxide. The porous aluminium oxide was fabricated by two-step anodization process with a electropolished aluminium foil. Before the first anodization step, the initial oxide layer with thickness of 10 nm was formed under the applied voltage of 1 V and later the anodization was continued under 40 V using oxalic acid solution. With the formation of the initial oxide layer, the anodization process was stable and the anodization current was constant throughout the process. In case of the absence of the initial oxide layer, the anodization was very unstable and the continuous increase in the anodization current was observed. This indicates the formation of the initial oxide layer on the aluminium surface prevents the burning of the surface due to the nonuniform distribution of the applied electric field, and allows the stable anodization process required for the porous aluminium oxide.