• 한국해양공학회지
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• 제30권6호
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• pp.440-450
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• 2016

The capsizing and consequent sinking of a coastal car ferry was recently reported, with numerous human casualties. The primary cause was determined to be a sudden turn with improperly stowed and secured cargo. Part I of this study introduces how long term acceleration components are determined from seakeeping analyses. A carferry with a displacement of 1,633 tonf was selected as the target vessel. Sea data that included the significant wave heights and periods were collected at four observation buoys, some of which were far away from two main voyage routes: Incheon-Jeju and Pusan-Jeju. Frequency response analyses were performed to obtain the linearized radiation force coefficients, hydrostatic stiffnesses, and wave excitation forces. Time response analyses were sequentially performed to produce the motion-induced acceleration processes. The probabilistic distributions of the acceleration components were determined using a peak and valley counting method. Long term extreme acceleration components were proposed as a final result.

• Journal of Power Electronics
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• 제11권6호
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• pp.837-845
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• 2011

This paper proposes phase current reconstruction techniques for two-phase two-leg and two-phase four-leg inverters using a single current sensor. In the proposed methods, one phase current is sampled simultaneously with a particular branch current by using only one current sensor, and then current reconstruction algorithms are applied to extract the information on two phase currents from the sensor output. The sampled current information is periodically updated at the peak and the valley of the triangular carrier waveform in each switching cycle of pulse-width modulation (PWM). The voltage vector spaces where the phase currents can be reconstructed are evaluated. Compared to the existing method using two individual current sensors in two phases, the proposed schemes can save implementation cost since it is possible to remove one current sensor. In addition, the proposed methods are free from gain discrepancy issues between two current sensors. Simulations and experiments show excellent current reconstruction performance of the proposed methods.

• 전기학회논문지
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• 제63권1호
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• pp.10-17
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• 2014

The Jeju Special Self-Government Provincial Government has made the plan penetrating gradually electric vehicles(EVs) in the Jeju Special Self-Government Province(Jejudo). However the effects of EVs penetration on the electrical grid of the Jejudo is not reported. In this paper the yearly electric energy consumed by the EVs was calculated and the effects of the EV penetration on the peak power of the grid were analyzed in the Jejudo for the future 10 years, and we hope that our study results will help the governors realize the EVs penetration plan in the Jejudo. The calculation results show that the rate of the electric energy used by the EVs will become to 2.9% at its maximum at the 2017 year when the penetration rate of EVs in passenger cars becomes 10%, and the rate of the electric energy consumed by the EVs will become to 9.4% at its maximum at the 2020 year when the penetration rate of EVs in passenger cars becomes 30%. The concepts of smart-charging capacity and 100%-valley-filling charging capacity of the grid were defined and calculated for the Jeju Grid, and the grid was analyzed to have the sufficient EV charging capacity until the 2022 year.

• Natural Product Sciences
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• 제14권3호
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• pp.152-155
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• 2008

An HPLC-ESI-MS method has been developed to identify and quantify two main tetracyclic triterpenes, alisol B 23-acetate and alisol C 23-acetate in the Alismatis Rhizoma (Taeg-Sa). The relative distribution of the two triterpenes in the methanolic extract of commercially available Alismatis Rhizoma was established by selective ion monitoring (SIM) mode via electrospray ionization (ESI) source. Regression equations revealed good linear relationship, and the correlation coefficients were 0.999 and 0.998 for alisol B 23-acetate and alisol C 23-acetate, respectively, between the peak areas of the components and their concentration in a range of $0.06-2.0{\mu}g/mL$. It was found that there were significant differences in the amount of alisol B 23-acetate and alisol C 23-acetate between Korean and Chinese origins. The results showed that this method could be used to identify the two components in Alismatis Rhizoma with high sensitivity and selectivity.

• 한국환경과학회지
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• 제12권2호
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• pp.101-109
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• 2003

Yangdong village is located at Kangdong-myun, Kyungju, Kyungsangbuk-do, Korea. There are two major families, the Sons of Wallsung beginned from Son, So(1433∼1484) and the Lees of Yeohkang the descendant of Lee, Unjeok. They are lived together under check and help for 500 years. The village located on the hill of Ankang plain. There are Homyung mountain and Sonaiu peak in front of it and Solchang mountain on the back. 47 shaped ridges form Blue dragon to the east, and White tiger to the west. Ahnrockchon flows from north Joined Hyungsan river and flows into Youngilman. Therefore the village is located at mountain on it's back and along with stream. Buildings are deployed on the valley between hills, it is not easily detected, but it give it's atmosphere of mountain village. Village location and space composition combined with natural environment, folk belief, feng-shui, and social system of confucianism. Blended buildings affected between ruling and ruled classes or among different families shown environmental design accomplishing united cultural space. The prospect of Yangdong village, a mountain village, expressed two sides of visible scenery of open inside and invisible from outside. Observation point such as head family house, pavilion, and village school are deployed at the point taking bird's-eye view, which striving mental stability.

• Journal of Electrical Engineering and Technology
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• 제11권4호
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• pp.905-914
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• 2016

This paper proposes a new phase current reconstruction technique for interleaved three-phase bidirectional dc-dc converters using a single current sensor. In the proposed current reconstruction algorithm, a single current sensor is employed at the dc-link, and the dc-link current information is sampled at either the peak or valley point of the pulse-width modulation (PWM) carriers regularly. From the obtained current information, all phase currents are reconstructed in a single PWM cycle. After that, the digital current controller is applied to achieve current balancing in each phase. Compare to the previous multiple current sensor method, the proposed strategy reduces the number of the current sensors in the interleaved three-phase bidirectional converter as well as reducing potential current sensing error caused by non-ideal characteristics of the multiple current sensors. The effectiveness of the proposed method is verified from the experiments based on a 3kW three-phase bidirectional converter prototype for the automotive battery charging application.

• 한국음향학회지
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• 제27권8호
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• pp.418-426
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• 2008

본 논문에서는 스펙트로그램에서 마루와 골을 이용한 주파수 채널 분할 알고리즘을 제안한다. 주파수 채널 분할 문제는 동일한 음원으로부터 발생한 음성이 포함된 주파수 채널들을 하나의 그룹으로 묶는 것을 의미한다. 제안된 알고리즘은 입력 신호의 평탄화된 스펙트럼에 기반한 알고리즘이다. 평탄화된 스펙트럼에서 마루와 골은 각각 세그먼트의 중심과 경계를 판단하기 위해 사용된다. 각 세그먼트를 하나의 소리로 묶는 그룹핑 단계 이전에 제안된 알고리즘에 의한 세그멘테이션 결과가 유용함을 평가하기 위하여 이상적인 마스크에 의한 세그멘테이션 결과와 제안된 방법을 비교한다. 제안된 방법을 협대역 잡음, 광대역 잡음, 다른 음성신호와 혼합된 음성신호에 대하여 실험하였다.

• 말소리와 음성과학
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• 제6권4호
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• pp.53-65
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• 2014

The current research examines whether pitch contour shapes in North Kyungsang pitch accent contrasts provide a phonetic dimension for phonological discreteness in a mimicry task. Two pitch accent continua resynthesized were created for HH vs. HL and HH vs. LH. To confirm a phonetic dimension for accounting for pitch accent categories in North Kyungsang Korean, the mimicries of speakers of two dialects (i.e., North Kyungsang & South Cholla) were compared. One of the findings showed that, for North Kyungsang speakers, the range of mean f0 peak times was a phonetic dimension undergoing a continuous shift within a stimulus continuum for both HH vs. HL and HH vs. LH. On the other hand, for South Cholla speakers, there were no apparent shifts around categorical boundaries for either HH vs. HL or HH vs. LH. Regarding individual mimicries on f0 peak timing, there are many variations. For HH vs. LH, three North Kyungsang speakers showed a discrete pattern reflecting a shift in phonological categories, but for HH vs. HL, there was no such distinction showing a categorical shift, though there were statistically significant differences for two speakers. Interestingly, one of the North Kyungsang speakers showed a continuous phonetic dimension for both HH vs. HL and HH vs. LH. Lastly, the f0 valley timing did not exhibit a discrete or gradient phonetic dimension for speakers of either dialect. On the basis of these results, what is interesting is that the tonal target such as high tone in North Kyungsang pitch accent categories within the autosegmental-metrical (AM) theory may be realized within individual cognitive systems for representing the interaction of perception and production.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1266_1267
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• 2009

신재생 에너지 태양광을 활용하기 위한 태양광 발전에 있어서 기존의 고가의 실리콘 기판 대신 저가의 박막형 태양전지 연구가 활발히 진행 되고 있다. 본 연구에서는 박막형 태양전지에 있어서 태양광의 투과층으로 사용되는 CdS 박막의 열처리에 따른 특성을 연구하였다. 실험은 CdS박막을 Sputtering법으로 동일한 조건에서 제조하였고 이 박막을 $200^{\circ}C$, $300^{\circ}C$, $400^{\circ}C$, $500^{\circ}C$, $600^{\circ}C$까지 열처리 하였다. 열처리 전과 후 Ellipsometer를 이용한 박막의 두께 변화, 표면의 RMS Roughness와 Peak to Valley Roughness의 변화 그리고 결정 구조변화 등을 조사하였다. 박막의 두께는 열처리 전보다 처리 후 두께가 얇아졌으나 거칠기나 결정성은 열처리 온도에 따라 거칠어지고 결정성이 떨어졌다.

• 정보처리학회논문지B
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• 제14B권4호
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• pp.241-248
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• 2007

본 논문은 광학 흐름을 추정하는데 있어서 최적 정규화 매개변수를 결정하기 위한 L-curve 모서리 검출 방법을 제안한다. 기존의 곡률법은 L-curve의 곡률 그래프에서 최대 위치를 찾는 반면, 제안한 방법은 바로 우측 음의 계곡과의 곡률 차가 최대가 되는 양의 봉우리의 위치를 찾아서 매개변수 값을 결정한다. 이 방법으로 선정한 매개변수로 광학 흐름을 추정하면, 평균적으로 최소 오차로부터 단지 0.02 pixel/frame 차이가 나는 것이 실험을 통하여 보여진다. 또한 제안한 방법으로 기존의 모서리 검출법인 곡률법이나 적응 제거법에 비해 최소 오차에 가장 가까운 광학 흐름을 구할 수 있었다.