• 전력전자학회논문지
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• 제25권4호
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• pp.286-292
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• 2020

This study proposes a power decoupled multi-port dual-active-bridge (DAB) DC-DC converter employing multiple transformers. Conventional multiport DAB DC-DC converters experience a power coupling issue from the use of a single transformer, which essentially requires complex power decoupling control. To solve this issue, a multiport DAB DC-DC converter employing multiple transformers is proposed to decouple output power without additional complex control algorithms. The proposed converter uses multiple transformers that can expand output ports easily. Therefore, transformers and the proposed multi-port DAB converter can be designed simply. In addition, the number of coupling inductors can be reduced in the proposed three-port DAB converter compared with that in conventional multiport DAB converters. The power decoupling characteristics and equivalent circuit of the proposed converter are analyzed using theoretical model approaches. Finally, a 3-kW laboratory prototype is developed to verify the effectiveness of the proposed converter.

• 한국정보통신학회논문지
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• 제13권11호
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• pp.2267-2272
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• 2009

본 논문에서는 다층형 결합 선로를 이용한 6-단자 위상 상관기와 동일한 구조를 갖는 반송파 복원기 그리고 위상 변위기를 갖는 일원화된 6-단자 직접변환 수신 전처리부를 설계 제작한다. 전력 분배기와 하이브리드 결합기로 구성되는 6-단자 소자는 다층형 결합 선로 구조로 이루어지며, 수신부 위상 상관기와 반송파 복원기 그리고 위상 변위기의 기본 구조 요소로 작용한다. 다층형 결합 선로 구조로 구성되는 일원화된 수신 전처리부는 구성이 간단하고 집적화가 용이하다. 설계 제작된 다층형 결합 구조 6-단자 수신 전처리부는 일정한 반송파 신호를 재생하고, PSK 전송 신호를 복원한다.

• 한국정보통신학회논문지
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• 제13권10호
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• pp.2039-2044
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• 2009

본 논문에서는 다층형 결합 선로를 이용한 PSK 반송파 신호 복원 회로를 해석하고 설계 제작한다. 다층형 결합 선로 구조의 coupled line으로 구성되는 반송파 복원 6단자 소자는 다층형 구조를 가지며, 수신 전처리부의 6 단자 위상 상관기 구조와 동일한 구조를 갖는 일원화된 수신 구조 구현이 가능하다. 아울러 다층 결합 선로 6 단자 위상 상관기를 이용한 RML 기반 다중 모드 동기 복조형 반송파 신호 복원이 가능한 다층형 결합 선로 반송파 복원 회로 구조를 제안한다. 설계 제작된 다층형 결합 선로 구조 반송파 복원회로에 의한 직교 위상편이 방식 신호의 반송파 신호는 일정한 위상값과 반사 소자에 의해 발생되는 ${\pm}3o$ 이내인 위상차를 갖는 양호한 PSK 반송파 신호 특성을 나타내었다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제35회 추계학술대회논문집
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• pp.479-483
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• 2010

본 연구는 하이브리드 로켓 연소에서 원통형 멀티 포트 그레인과 스월 인젝터 적용 시 각각 후퇴율 증가의 장점을 취합하고자 수행하였으며, 연료 포트 수와 스월 인젝터의 배치에 따른 후퇴율 변화에 대한 실험을 수행 하였다. 실험 결과 멀티 포트 그레인에 샤워 헤드 형태의 인젝터를 적용한 것보다 스월 인젝터를 적용한 경우의 후퇴율이 증가되는 것을 확인 할 수 있었다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 추계종합학술대회 논문집
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• pp.471-474
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• 1998

In this paper, we consider the problem of optimal broadcasting in recursive circulants under multi-port communication model. Recursive circulant G(N, d) that is defined to be a circulant graph with N vertices and jumps of powers of d is a useful interconnection network from the viewpoint of network metrices. Our model assumes that a processor can transmit a message to $\alpha$ neighboring processors simultaneously where $\alpha$ is two or three. For the broadcasting problem, we introduce 3-trees and 4-trees. And then we show that 3-trees and 4-trees are minimum broadcast trees in 2-port model and 3-port model. Using the above results, we show that recursive circulants g(2m, 2) have optimum broadcasting time in 2-port model and 3-port model.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.533-534
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• 2008

By using Dual Port DRAM to Multi-media SoC, an improved performance is achieved in this paper. The proposed scheme greatly help the multi-media SoC like a application for full HDTV, and it can be extended to the application field which is needed the low access latency with heavy traffic. Additionally, the proposed scheme help to down the BUM cost of system.

• 한국항해항만학회지
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• 제33권4호
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• pp.271-275
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• 2009

A strategic decision making on location selection for product transportation includes many tangible and untangible factors. To choose the best locations is a difficult job in the sense that objectives usually conflict with each other. In this paper, we consider a multi stage multi criteria transshipment problem with different types of items to be transported from the sources to the destination points. For the optimization of the problem, a goal programming formulation will be presented in which the location selection for each product type will be determined under the multi objective criteria. In the study, we generalize the transshipment model with a variety of product types and finite number of different intermediate nodes between origins and destinations. For the selection of the criteria we selected the costs(fixed cost and transportation cost), location numbers, and unsatisfied demand for each type of products in multi stage transportation, which are the main goals in transshipment modelling problems. The related conditions are also modelled through linear formats.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2000년도 추계학술대회논문집
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• pp.85.2-93
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• 2000

A demand of marine outfall system have been much increased for the effective disposal of the wastewater due to population and industrial development at the coastal areas. The outfall system discharges primary or secondary treated effluent into coastline or at the deep water, or between these two. The discharge is carried out by constructing a pipeline on the sea bed with a diffuser or with a tunnel, risers and appropriate. The effluent, which has a density similar to that of fresh water, rises to the sea surface forming plume or jet, together with entraining the surrounding salt water and becomes very dilute. Thus there have been growing interests about plume behaviour around the outfall system. Plume or jet discharged from single-port or multi-port diffuser might cause certain impacts on coastal environment. Near field mixing characteristics of discharged water field using CORMIX model with has been studied for effective outfall design various conditions on ambient current, depth, flow rate, effluent concentration, diffuser specification, port specification etc.. This kind of analysis is necessary to deal with water quality problems caused by the ocean discharge. The analyzed vesult was applied to the Pusan Jungang dffluent outfall system plan.

• 한국IT서비스학회지
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• 제11권3호
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• pp.1-16
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• 2012

This paper is aimed to present a fuzzy decision-making approach to deal with disaster recovery priority decision problem in information system. We derive an evaluation approach based on TOPSIS(Technique for Order Performance by Similarity to Ideal Solution), to help disaster recovery priority decision of total information system for port logistics in a fuzzy environment where the vagueness and subjectivity are handled with linguistic terms parameterized by trapezoidal fuzzy numbers. This study applies the fuzzy multi-criteria decision-making method to determine the importance weight of evaluation criteria and to synthesize the ratings of candidate disaster recovery system. Aggregated the evaluators' attitude toward preference, then TOPSIS is employed to obtain a crisp overall performance value for each alternative to make a final decision. This approach is demonstrated with a real case study involving 4 evaluation criteria(system dependence, RTO, loss, alternative business support), 7 information systems for port logistics assessed by 5 evaluators from Maritime Affairs and Port Office.

• 한국항해항만학회지
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• 제34권7호
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• pp.587-594
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• 2010

The positive and negative opinion to cargo demand of Incheon's SAMT in the near future remains cloudy. Considering port and shipping environmental changes and the logistics situation of China which explains the lack of facilities in Chinese airports, the creating of SAMT cargoes of the Incheon region could catches a favorable opportunity to be a logistics hub in the North-East Asia. On the other hand, as open-sky policy and direct-call service has been carried out between China and N.A.(North America), Incheon could cause a loss of competitiveness in SAMT because the enhancement in the aspect of the connectivity of Chinese airlines and shipping lines makes customer sent to last destination their cargoes whenever they want. In the same context, this paper analyses on conditions of domestic and international SAMT and proposes in this uncertainty future forecasting of SAMT of Incheon by scenario planning according to changes in integrated SAMT, measuring the likelihood of final scenario. This study shows the Sea & Air multi-transport volume will have either slight increase or decrease from the current condition. Consequently, RFS expansion and system & service improvement through strong ties with major cities in China will be required in a short run aspect. Nonetheless, we also need to take domestic & international transportation environment into account in the long run.