• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.12
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• pp.2196-2201
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• 2011

According to the 5th national plan for electric power demand and supply, the 3rd HVDC link will be installed between KEPCO and Jeju Island system and go into operation in June, 2016. However, if it adopt LCC HVDC, Jeju power system could be in voltage instable condition. In order to solve the problem, we propose the application of VSC HVDC to the 3rd HVDC project. In the past, VSC HVDC has many disadvantages such as, inefficiency in conversion, size limit, and expensiveness, compared to LCC HVDC. Recently, the new technologies and the demand for renewable energy interconnection are leading a large growth in VSC HVDC market. In this paper, we will introduce the technical and market trends of VSC HVDC and power system stability analysis results for Jeju power system having LCC and VSC HVDCs.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.245-248
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• 2000

해양음향 토모그래피 수행을 위해 필수적인 Forward 모의 알고리즘을 연구를 통해 Forward 문제에서의 선결문제(음파 전달경로의 안정성, 식별능력 및 분해능)를 고잘하였다. 이를 위해 동해의 기존 관측 자료를 이용하여 평균해양에 대한 음속구조 및 EOF 분석을 수행, 재현된 음속구조를 이용, 음선 모델에 의한 고유음선 정보를 파악하여 고유음선의 도달경로 및 도달시간의 비교를 시도하였다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.9 no.2
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• pp.189-197
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• 1997

The vaporizing characteristics of LNG(liquefied natural gas) via heat exchanger with sea water are analytically studied for an open rack vaporizer(ORV). This study is intended to supply the design data for the domestic fabrication of the corrosion-resistant vaporizer tube. A computational program is developed to predict the exit temperature of LNG for various conditions. In the program, thesimple and justifiable heat transfer models are selected for fully-developed internal flow of LNG, the star-shaped finned-tube, and the external falling films of sea water, as well as the possible ice formation and the fouling on the tube walls. It is found that the enongh corrugation inside of the tube wall is the most significant in the vaporizer performance for the current operating conditions. the effects of other design parameters on the heat exchanger between LNG and sea water are quantitatively presented.

• Korean Journal of Head & Neck Oncology
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• v.20 no.1
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• pp.55-57
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• 2004

Cervical thymic cysts are not very common. Two-thirds of the lesions are detected in the 1st decade of life, when the thymus is biggest in size and most active. The remaining one-third in the 2nd and 3rd decades. Due to its rarity, cervical thymic cyst is seldom included in the differential diagnosis of a neck mass. Approximately 90 cases have been reported thus far, and most of these cases have occurred asymptomatically in children and adults. We report a case of a 44-year old man with a cervical thymic cyst mimicking branchial cleft cyst.

• 한국데이터정보과학회:학술대회논문집
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• 2003.10a
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• pp.139-145
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• 2003

본 논문에서는 강수 자료의 예측에 사용되는 3-모수 카파 분포(KD3)에서의 모수 추정 방법을 알아보고 시뮬레이션을 통하여 모수 추정 방법에 따른 성능을 비교해 보았다. 이 분포의 모수 $\alpha,\;\beta,\;\mu$를 추정하기 위하여 적률추정법(MME), L-적률 추정법(LME), 최우추정법(MLE)을 적용하였다. 소표본의 경우뿐만 아니라 대표본의 경우에도 시뮬레이션을 통하여 추정법들의 성능을 비교하였다. 적률 추정법과 L-적률 추정법에서는 제약조건 하에서의 1차원 Newton-Raphson방법을 수정하여 이용하였다. MSE를 기준으로 한 시뮬레이션 결과, KD3의 모수 추정에 있어서 표본의 크기가 100보다 작으면 LME의 적용을 추천하고 표본의 크기가 100이상이면 MLE를 추천한다.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.632-634
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• 1996

In modern train systems, the high-speed and the high-density of train operation have been required. Effective train control systems need various information interchanged between the ground-site and on-board devices. So the systems are essential to the digital systems to admit lots of information and to raise the accuracy of transmission. In this paper, it is dealt with n bi-directional transmission of digital information between on-board devices and ground-site. Especially, this paper shows the experiment of bi-directional transmission of mass information by using transponder.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.629-631
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• 1996

Recently, to increasing the transportation efficiency is to be a important view points in modem railway systems. Therefore the railway communication has an important meaning for the safety of train traffic. In this paper, we have proposed to use HDLC protocol for ground-to-train data transmission, which has some merits of efficiency in data transmission, reliability and bit transparency. Also we describes the HDLC application for data transmission in railway communication.

• Korean Journal of Head & Neck Oncology
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• v.16 no.1
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• pp.77-79
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• 2000

Canalicular adenoma is a uncommon benign salivary gland tumor and it most frequently involves minor salivary gland of upper lip. It rarely occurs in parotid gland. The canalicular tumor of parotid gland can be manifestes clinically and pathologically as a multifocal lesion, which is not generally seen with other intraoral salivary gland tumors. Recently, we experienced a case of multifocal canalicular adenoma occurred on parotid gland in a 65-year-old woman and report it to support the view that canalicular adenoma occur rarely in parotid gland, and is recognizable entities.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.6
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• pp.1781-1791
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• 1991

For the cracked plate under transient temperature distribution, J-integral is expressed in the form of line integral by using convolution integral. The J$_{1}$ integral is calculated for a through line center cracked steel plate under thermal and mechanical loading conditions and the calculated values are in good agreement with previous results. The effect of inertia term on the J$_{1}$ integral is not negligible for a glass but for a steel. For the glass plate, the rates of J$_{1}$ integral value to time increase if the values of material properties such as specific heat, thermal conductivity, thermal diffusivity and Young`s modulus as well as crack length and temperature difference in cracked edge increase.

• Korean Journal of Head & Neck Oncology
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• v.9 no.1
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• pp.56-62
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• 1993

The parathyroid carcinoma is a rare cause of primary hyperparathyroidism. There was approximately 170 reports in the would literature. and only two documented cases in Korean literature. It is still difficult to distinguish. histologically, benign from malignant parathyroid tumors. However, if diagnotic criteria are that strict, it can be suscessfully cured by initial operation. The initial operation should be an en bloc resection of the tumor, avoiding rupture of the tumor capsule and spillage of tumor cells. This report details the management of a 51 year old female with functioning parathyroid carcinoma who underwent an en bloc resection of the tumor at the time of initial operation.