• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.486-487
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• 2012

In this paper, novel three-port active power decoupling (APD) method for applying 250[W] micro-inverter. This type using third port for active power decoupling stores the surplus energy and supplies sufficient energy to grid. Conventional decoupling circuit is applied in single phase grid connected micro-inverter especially single-stage configuration like flyback-type DC-AC inverter. In this passive power decoupling method, electrolytic capacitor with large capacitance is needed for decoupling from constant DC power and instantaneous AC power. However the decoupling capacitor is replaced with film capacitor by using APD, thus the overall system can achieve smaller size and long lifespan. Proposed three-port flyback inverter is verified by design and simulation.

• 한국항만경제학회지
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• 제20권1호
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• pp.21-42
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• 2004

This paper addresses the operation, problems, and development policy of Gwangyang Port, Korea. This paper aims to analyze the operation condition and problems of Gwangyang Port and suggest long-term policies for developing Gwangyang Port as a logistic hub in northeast period. It is made up of three main sections: the operation, problems, and forecast of freight volumes; analysis of operational results of Gwangyang Port; development strategies of Gwangyang Port as a Logistics Hub. This paper was mainly based on a review of current papers/reports, an analysis of secondary data, and questionnaire survey. The major development strategies identified consisted of expansion regular service sea-route, formation of inter-modal transportation system, strengthening of port sales for Gwangyang port's recognition, securing operation-profits by fixed cargo volume, and promotion of free tread zone.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 1998년도 추계학술대회논문집:21세기에 대비한 지능형 통합항만관리
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• pp.19-49
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• 1998

I try to introduce three types of designs for automatic container operating system which are designed by Institute of Japan Port Research in 1996. Each types are designedto fit with the situations of Japan Port. 'A'type of these designs adapts Dual Container Crane, AGV, RMG, etc. 'B'type of these designs adapts Dual Container Crane, AGV, OHBC, RTG. And 'C'type of these designs adapts Single Container Crane, AGV, OHBC, etc. Even if three designs are introduced, they have some problems to solve for the future. They are Lashing work, Refeer container problem, check for container and seal in main gate, Establishing EDI NETWORK, etc. I expect that this paper will be a helps to development of our port industry.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2005년도 추계학술대회 논문집
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• pp.327-332
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• 2005

본 연구는 항만혁신클러스터의 성공도 예측과 평가요소를 분석하기 위한 것이다. 이를 위해 본 연구에서는 항만혁신클러스터 정책, 자원, 운영 등 3가지의 평가항목으로 구분하였다. 그리고 3항목은 다시 12개의 요소로 세분화하였다. 평가요소의 중요도는 코호넨 네트웍에 의해 산출되었다. 그 결과 자원요소가 다른 요소에 비해 가장 중요한 것으로 나타났다.

• 한국항만경제학회지
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• 제29권2호
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• pp.39-61
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• 2013

동북아 지역내 경제성장을 끌고 나가는 중국은 해운항만 분야에서는 환적화물의 흐름과 초대형 선박들의 기항지 선택 및 선사들의 네트워크 구축에 대한 영향을 통하여 동북아 단일 시장의 통합을 선도하고 있으며, 지역내 주요 항만들에 다양한 영향을 주고 있다. 이 연구는 중국 주요 항만-상해항, 천진항, 홍콩항 포함-들의 개발과정과 항만들간 개발의 상호관계를 시계열적으로 고찰함으로써 중국 항만의 미래를 조망하는 데에 유익한 시사점을 도출하는 데에 초점을 두고 있다. 주요 항만의 개발과정과 특성은 다음과 같다. 홍콩항은 고베항의 터미널을 세분화 전략보다는 물동량의 증가 추이에 따라 단계적으로 시설을 대형화하는 전략을 취하면서 운영의 안정성을 추구하였다. 상해항은 물동량의 지속적 증가에도 불구하고 2000년대 초까지 확장에 보수적 태도를 견지하였으며, 컨테이너 부두시설을 집중화하여 시설 대형화의 장점을 취하고 있다. 천진항도 타 중국항만과 유사하게 물동량의 증가에 따라 단계적 부두 확충과 부두시설의 집중과 특화 전략을 취하고 있다. 중국 거점항만들에 대한 패널자료와 패널회귀분석은 이들 항만들이 각기 독자적 수요기반을 갖고 있음을 시사하고 있으며, 항만들간 상관관계가 1980년대에는 낮았지만, 1990년대 이후 점차적으로 동시적 상관관계가 높아지는 것을 나타냈다.

• Journal of Chest Surgery
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• 제48권6호
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• pp.387-392
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• 2015

Background: The aim of this study was to evaluate the feasibility of single-port video-assisted thoracic surgery (VATS) in the treatment of secondary spontaneous pneumothorax (SSP). Methods: Twenty-four patients who were scheduled to undergo single-port VATS for SSP were studied. The medical records of the patients were retrospectively reviewed. The mean follow-up duration was $26.1{\pm}19.8$ months. In order to evaluate the feasibility of single-port VATS for SSP, the postoperative results of single-port VATS (n=15) in patients with emphysema were compared with those of emphysematous patients who underwent three-port VATS (n=15) during the study period. Results: Single-port VATS was feasible in 19 of 24 patients (79.2%), while an additional port was needed in five patients. In the single-port VATS patients, the median operation time, duration of chest tube drainage, and hospital stay were 84.0 minutes, one day, and two days, respectively. Postoperative complications included prolonged chest tube drainage for more than five days (n=1), wound infection (n=1), and vocal fold palsy (n=1). No recurrence of pneumothorax was observed during the follow-up period. The median operation time, duration of chest tube drainage, and hospital stay of the emphysematous patients who underwent single-port VATS were shorter than those who underwent three-port VATS group (p<0.05 for all parameters). Conclusion: Single-port VATS proved to be a feasible procedure in the treatment of patients with secondary spontaneous pneumothorax.

• 한국자동차공학회논문집
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• 제3권5호
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• pp.82-89
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• 1995

The three-dimensional fluid motion through the intake port and cylinder of a single DOHC SI engine was investigated with a commercial computational fluid dynamics simulation program, STAR-CD. This domain includes the intake port, intake valves and combustion chamber. Steady induction port flows for various valve lifts have been simulated for an actual engine configuration. The geometry was obtained by direct interface with a three-dimensional CAD software for complicated port and valve shape. The computational grid was generated using the commercial preprocessor ICEM CFD/CAE. Detailed procedures were presented on the generation of the geometry and the block-structured mesh. A standard k-${\varepsilon}$ turbulent model was applied to consider the complexity of the geometry and the fluid motion. The global flow patterns and the distributions of various quantities, such as pressure, velocity magnitude around the valve seat etc., were examined. The computational results, such as mass flow rate, discharge coefficient etc., for various valve lifts were compard with the experimental results and the computational results were found in good agreement with the experiment.

• Journal of Korea Trade
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• 제23권4호
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• pp.17-29
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• 2019

Purpose - This study examines the relationship between public-private partnerships and the performance of ports based on three factors: the quality of the port infrastructure, container throughput, and logistic performance in three Latin American countries, Mexico, Panama, and Brazil, for the period of 1994-2017. Design/methodology - The selected countries are top ranked in terms of container throughput in Latin America. The methodology employs secondary data from the World Bank (Quality of Port Infrastructure, Logistics Performance Index, and Private Participation in infrastructure database). Findings - Overall, the results revealed that the private investment of these countries varies significantly over the past couple decades. Panama, with the least public-private investment over the study period, performs better than Mexico and Brazil with regards to port quality infrastructure and container throughput. For ports in the selected countries to keep up with global competition, there is a need to enhance efficiency. Originality/value - Compared with ports in Asia, Latin American ports are lagging behind with respect to container throughput and efficiency. This study suggests greater collaboration from the private sector, academia, and other organizations, as well as a review of the regulatory framework to ensure better transparency and project allocation. Throwing more light on the public-private investment environment of Mexico, Brazil, and Panama, this study offers policy makers and regulators insightful information on port infrastructure.

• Journal of Information Processing Systems
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• 제19권4호
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• pp.407-416
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• 2023

In order to effectively relieve the traffic pressure of the city, ensure the smooth flow of freight and promote the development of the logistics industry, the selection of appropriate port logistics location is the basis of giving full play to the port logistics function. In order to better realize the selection of port logistics, this paper adopts the entropy weight method to set up a multi-dimensional evaluation index, and constructs the evaluation model of port logistics location. Then through the actual case, from the environmental dimension and economic competition dimension to make choices and analysis. The results show that port d has the largest logistics competitiveness and the highest relative proximity among the three indicators of hinterland city economic activity, hinterland economic structure, and port operation capacity of different port logistics locations, which has absolute advantages. It is hoped that the research results can provide a reference for the multi-dimensional selection of port logistics site selections.

• 전력전자학회논문지
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• 제22권4호
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• pp.336-344
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• 2017

This paper presents the three-port DC-DC converter modeling and controller design procedure, which is part of the solid-state transformer (SST) to interface medium voltage AC grid to bipolar DC distribution network. Due to the high primary side DC link voltage, the proposed converter employs the three-level neutral point clamped (NPC) topology at the primary side and 2-two level half bridge circuits for each DC distribution network. For the proposed converter particular structure, this paper conducts modeling the three winding transformer and the power transfer between each port. A decoupling method is adopted to simplify the power transfer model. The voltage controller design procedure is presented. In addition, the output current sharing controller is employed for current balancing between the parallel-connected secondary output ports. The proposed circuit and controller performance are verified by experimental results using a 30 kW prototype SST system.