• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.594-599
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• 2007

According to separation policy between rail infrastructure and operation, the National Railroad Administration was converted to Korea Railroad Cooperation on Jan, 2005. That makes railway service assessment regarded as essential. About this matter, Section 15 of the Framework Act on Rail Industry Development and section 26 of the Rail Business Act shows that the railway service assessment should be conducted every 2 years. The government can officially announce the result and give orders operation company to improve service level. In the first railway service assessment in 2006, the principal railroad lines and stations were investigated. Rail supply service index and customer satisfaction index are introduced. It includes service items of supply, reliability, convenience, safety and customer satisfaction. This study presents the contents of 2006 rail service assessment. Some points of assessment which should be improved are analyzed as well.

• 대한전기학회논문지
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• 제31권7호
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• pp.11-17
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• 1982

In this paper, a reliable and convenient evaluation method for the adequacy of any radial distribution line's voltage drop is proposed for improvement of the voltage regulation of the distribution line under operation. Using the voltage measurement of the first load branch point and the last point on the given distribution line its average line voltage drop and the line voltage drop variance by pure load variation are computed. And by these values and allowable or required line drop from proper voltage regulation view point, present adequency index and operation improvement index of the line drop are newly introduced for the evaluation of the given distribution line's voltage regulation. As a result of application to the 4 cases of study, the proposed method is proved to be reliable and convenient.

• 전자공학회논문지D
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• 제36D권5호
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• pp.88-98
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• 1999

레이저의 종축방향으로 회절격자층을 형성하는 위쪽 클래딩 층의 가운데 부분의 굴절률을 양 옆부분과 다르게 하여 유효위상천이 효과를 넓은 영역에서 얻는 refractive index midulated (RIM) DFB 레이저를 제안한다.RIM-DFB 레이저는 SHB 효과를 줄이기 위하여 기존에 제안되었던 회절격자의 주기를 변화시켜 넓은 영역에 걸쳐서 유효 위상 천이를 주는 corrugation pitch modualtion (CPM) 방법과 레이저의 종축 방향으로 결합계수를 달리하여 주는 distributed coupling coefficients (DCC) 방법의 효과를 동시에 얻을 수 있는 실현 가능한 구조이다. 급격한 위상천이가 없기 때문에 광자밀도분포가 균일해져 SHB 효과가 줄어 들게 되며 레이저 공진기 가운데 부분의 결합계수가 양 옆 부분의 결합계수보다 커서 분포결합계수의 효과를 주기 때문에λ/4 위상천이 레이저와 CPM-DFB 레이저에 비해 고출력에서 좋은 단일 모드 특성을 보인다. 그리고, 굴절률이 다른 가운데 부분의 길이가 RIM-DFB 레이저의 동작특성에 미치는 영향에 대하여 연구하였다.

• Archives of Plastic Surgery
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• 제32권4호
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• pp.543-546
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• 2005

Pulmonary embolism is a one of the major cause of postoperative death. Surgery predisposes patients to pulmonary embolism, even as late as one month after the operation. The accurate detection of pulmonary embolism remains difficult, and the differential diagnosis is extensive. The prevention of pulmonary embolism is thus of paramount importance. We report a case of pulmonary embolism after coverage of pressure sore on the left ischium on the 8th day after operation. The patient was 60 years old, a severe smoker, in the high quantity of body mass index and had hypertension. The risk factors are 60 years of age or older who were in the highest quantity of body mass index. Heavy cigarette smoking and high blood pressure are also identified as risk factors. Plastic surgeons should keep the probability of pulmonary embolism development after operation in mind. When taking history, the risk factors should be checked certainly. The immobilization may explain the probability of pulmonary embolism development. Therefore absolute bed rest or positional maintenance should be avoided. Until recently, low molecular weight heparin has been used for preoperative prophylaxis. Plastic surgeons should be concerned in low molecular weight heparin for prophylaxis of the pulmonary embolism and study the indications and effectiveness in liposuction or abdominoplasty.

• 한국농공학회논문집
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• 제60권3호
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• pp.95-105
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• 2018

Understanding the composition of the dam inflow can improve the efficiency of dam operation considering the seasonal characteristics. Hydrograph analysis is one of the methods to identify the characteristics of dam inflow. In addition, baseflow separation on the dam inflow can be affected by anthropogenic influences depending on dam locations. In this regard, the objectives of this study are 1) to analyze yearly and monthly baseflow contribution to the dam inflow and 2) to compare the baseflow contribution to the inflow in dams located upstream and downstream of the watershed. The result shows that the estimated baseflow index was smaller in the upstream dams compared to the downstream dams. Discharge from the upstream water infrastructure including dams and reservoirs can be a part of inflow into the downstream water infrastructure. Based on this scenario, the discharge regulated from the upstream dam could lead to overestimation of baseflow contribution to inflow into the downstream dam. We expect that the results from this study elucidate the role and function of dams and hence, contribute to the efficient operation of dams located in the upstream and the downstream of the watershed.

• 대한한방부인과학회지
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• 제28권2호
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• pp.183-192
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• 2015

Objectives : This study aims to report the effect of Korean medicine treatments on a sequela of operation of hallux valgus. Methods : The patient was treated with Dangkisoosan-gami, Acupuncture treatment including Herbal-Acupuncture and physical therapy. We evaluated treatment effects by circumference of foot and ankle, Edema index score by Body Composition Analyzer, Ankle-Brachial Index (ABI) and Visual Analogue Scale (VAS). Results : After 25 days of treatment, the symptoms such as lower extremity edema, foot pain and ankle pain were improved. Conclusions : In this case, Korean medicine treatments for a sequela of operation of hallux valgus was effective. But further studies are required to confirm the effect of these methods.

• 한국항만경제학회지
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• 제32권4호
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• pp.211-220
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• 2016

항만을 둘러싼 외부환경변화에 따라 항만의 지속가능한 운영에 대한 관심이 증가하는 추세이다. 다양한 분야에서 TBL을 활용한 지속가능성 평가가 진행되고 있으며, 항만도 지속가능성 평가를 위해 경제적 측면뿐만 아니라 사회적, 환경적 측면을 고려한 연구가 필요한 시점이다. 본 연구에서는 TBL을 접목하여 항만의 지속가능성 평가지표를 선정하고 중요도를 분석하여, 국내 주요 4대 항만에 대해 지속가능성을 평가하였다. 항만의 지속가능성을 위해서는 가치가 높은 물동량 확보와 함께 항만 운영과 인프라 및 자본 투자의 효율성 제고가 필요하며, 주변 지역의 연계성장과 함께 친환경적인 항만의 운영이 필요할 것이다.

• ETRI Journal
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• 제24권2호
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• pp.109-116
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• 2002

We propose a novel very short (< $300{\mu}m$) vertical directional coupler switch with high extinction ratios larger than 30 dB. The device consists of a switching operation induced section (SOIS), an extinction ratio adjusted section (ERAS), and an extinction ratio enhanced section (ERES). These are achieved by changing the refractive index of one core. The switching operation is induced by changing the refractive index of one core in the SOIS. The improvement of extinction ratios larger than 30 dB for both the cross and bar states is made by controlling the asymmetry of the refractive indices of both cores in the ERES. Through the ERAS, different extinction ratios between the cross and bar states at the end of the SOIS are changed to the same value. For this reason, the optimum asymmetry of the refractive indices of the cores for the maximum extinction ratios and the lengths of ERES are the same for cross and bar states. Design guidelines for high extinction ratios with large tolerances are presented.

• Nuclear Engineering and Technology
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• 제48권1호
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• pp.144-152
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• 2016

Human capabilities, such as technical/nontechnical skills, have begun to be recognized as crucial factors for nuclear safety. One of the most common ways to improve human capabilities in general is training. The nuclear industry has constantly developed and used training as a tool to increase plant efficiency and safety. An integrated training framework was suggested for one of those efforts, especially during simulation training sessions of nuclear power plant operation teams. The developed training evaluation methods are based on measuring the levels of situation awareness of teams in terms of the level of shared confidence and consensus as well as the accuracy of team situation awareness. Verification of the developed methods was conducted by analyzing the training data of real nuclear power plant operation teams. The teams that achieved higher level of shared confidence showed better performance in solving problem situations when coupled with high consensus index values. The accuracy of nuclear power plant operation teams' situation awareness was approximately the same or showed a similar trend as that of senior reactor operators' situation awareness calculated by a situation awareness accuracy index (SAAI). Teams that had higher SAAI values performed better and faster than those that had lower SAAI values.

• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.263-269
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• 2018

In this study, a selective inverter operation between a 2-level voltage source converter (VSC) and a 3-level T-type VSC (3LT VSC) is proposed to improve the efficiency of a 3LT VSC. The 3LT VSC topology, except for its neutral-point switches, has similar operations as that of the 2-level VSC. If an operation mode is changed according to efficiency, the efficiency can be improved because efficiencies of each methods are depending on current and MI (Modulation Index). The proposed method calculates the power losses of the two topologies and operates as the having lower losses. To calculate the losses, the switching and conduction losses based on the operation mode of each topology were analyzed. The controller determined the operation mode of the 2- or 3-level VSC based on the power loss calculated during every cycle. The validity of the proposed control scheme was investigated through simulation and experiments. The waveform and average efficiency of each method were compared.