• 한국전자파학회논문지
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• 제13권1호
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• pp.53-59
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• 2002

본 논문에서는 다중대역 피드를 위한 직교모느 변환기를 설계하였다. 직교모드 변환기의 전체적인 모양은 사각 테이퍼진 형태이고, 18~20 GHz에서 우원편파와 좌원편파를 발생시키기 위해 테이퍼 부분에 2개의 측면 포트를 두고, 직선포트는 30~45 GHz의 광대역에서 -20 dB 이하의 반사계수와 15 dB 이하의 분리도를 가지도록 설계하였다. 직선포트에서의 반사계수 특성을 향상시키기 위해서 측면포트에 얇은 격막을 삽입하였다. 전체적인 설계에 상용소프트웨어인 HFSS$^{R}$를 사용하였다.

• 대한안전경영과학회지
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• 제23권1호
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• pp.31-38
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• 2021

port is the intersection of highway, railway, waterway and other transportation modes, and is the key to realizing integrated transportation. There are many excellent ports around the Tumen River Region. With the obvious location advantages, Tumen River Region is an important part of Tumen River regional cooperation and development, and is the key to realizing the "borrow port to sea", which is raised in "China Tumen River regional cooperation and development planning outline -- regard Changjitu area as the development and opening leading area" (referred to as "planning outline"). This paper focus on the main ports in the Tumen River region, taking them as the research object. Furthermore, the paper makes the strategic plan for the port cluster in the Tumen River region as well as puts a collaboration scheme is proposed by analyzing the research reviews of the Tumen River region and the present situations of the main ports.

• Journal of Korea Trade
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• 제23권2호
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• pp.59-75
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• 2019

Purpose - The International Maritime Organization (IMO) has promulgated strict regulations on emissions in the maritime shipping industry. LNG (Liquefied Natural Gas) is, therefore, recognized as the optimal fuel alternative solution. The aim of this study is to select the most suitable location for an LNG bunkering port. This is formulated as a multiple-criteria ranking problem regarding four candidate ports in South Korea: the ports of Busan, Gwangyang, Incheon, and Ulsan. Design/Methodology/approach - An analysis employing the Consistent Fuzzy Preference Relation (CFPR) methodology is carried out, and the multiple-criteria evaluation of various factors influencing the location selection, such as the average loading speed of LNG, the number of total ships, the distance of the bunkering shuttle, and the degree of safety is performed. Then, based on the combination of both the collected real data and experts' preferences, the final ranking of the four ports is formulated. Findings - The port of Busan ranks first, followed by the ports of Gwangyang and Ulsan, with the port of Incheon last on the list. Originality/value - The Korean government could proceed with a clear vision of the candidate ports' ranking in terms of the LNG bunkering terminal selection problem.

• 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.

• 수산경영론집
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• 제53권3호
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• pp.85-101
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• 2022

This study analyzed the performance of the national fishing port development project, which lacked ex-post impact evaluation despite a lot of investment in terms of fishery income opportunities. Using micro data from the Census of Agriculture, Forestry, and Fisheries, the sales amount of fishery products and the proportion of fishery-related businesses were used as performance indicators. The fishery households in the fishing port area (treatment group) and those not in the area (control group) were classified through data pre-processing, and factors unrelated to the fishing ports were controlled using the propensity score matching difference-in-difference method. The analysis target is six fishing ports with large investment in from 2010 to 2014. As a result of the analysis, it was confirmed that the sales of fishery products increased significantly in four of the six fishing ports, and the proportion of fishery-related businesses increased in two fishing ports. The analysis method of this study can be fully utilized in the evaluation of the Fishing Community New Deal 300 Project, which is in need of performance analysis.

• Journal of information and communication convergence engineering
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• 제22권1호
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• pp.14-22
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• 2024

This study presents the design of a Wilkinson power divider for three-way output ports (WPD3OP), which incorporates a defected ground structure (DGS). An asymmetric power divider is integrated into the output ports of the conventional Wilkinson power divider (WPD), establishing a three-way output port configuration. The DGS introduces periodic or irregular patterns into the ground plane to suppress unwanted electromagnetic wave propagation, and its incorporation can enhance the performance of the power divider, in terms of the power-division ratio, isolation, and bandwidth, by reducing spurious resonances. The proposed design algorithm for an asymmetric power divider for three-way output ports is analyzed via circuit simulations using High-Frequency Simulation Software (HFSS). The results verify the validity of the proposed method. The analysis of the WPD3OP integrated with DGS certifies the achievement of a center frequency of 2 GHz. This confirmation is supported by schematic ideal design simulation results and measurements encompassing insertion losses, return losses, and isolation.

• 한국항해항만학회지
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• 제30권9호
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• pp.749-754
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• 2006

The maritime logistics environment including seaborne trade, shipping and ports is changing rapidly and continuously. Large containerships, mega carriers and global terminal operators try to achieve economies of scale and economies of scope. As a result of the changing environment, the competition between ports to achieve competitiveness is intensive. Port competition among China, Japan and Korea is becoming fiercer, both directly and indirectly, resulting from the increased trade in northeast Asia. Port development projects within each country stimulate more intensive port competition. As a result, overcapacity, fierce price competition and overlapping hinterland problems will be caused in the future. Co-operation for survival is considered as a strategy in order to solve anticipated problems caused by port competition Busan port, for instance, could co-operate with China and Japan as well as with other ports in Korea Terminal operators' expansion through investments including joint-ventures will make connections between ports smoother. At the port authority level, continuous cooperative interchange between countries is indispensable.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(1)
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• pp.241-244
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• 2000

In this paper, we investigate performance of OFDM employing macrodiversity selection on a shadowed multipath channel to reduce the effects of long-term shadowing. Three different situations are considered： independent shadowing with equidistant ports, independent shadowing with non-equidistant ports, and correlated shadowing. Numerical results show that OFDM performance is improved as the number of macrodiversity ports increases. In the situation where the user is much closer to certain port(s), performance becomes worse compared to that of the equidistant situation. In addition, as the correlation increases among the ports, the advantage of macrodiversity is reduced.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2015년도 춘계학술대회
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• pp.165-166
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• 2015

Sea-ports in Northern Vietnam have experienced a rapid growth of container throughput volume in recent years. To accompany with such development, huge investments also have been performed to enhance local ports capacity. It becomes a crucial task for the port authorities or the port stevedoring industry to improve the ports efficiency in order to customize national resources. In this paper, Data Envelopment Analysis (DEA) is employed to evaluate the relative efficiency of container terminals in Northern Vietnam by collecting data from terminals since 2005 up to now. The development progress of the given terminals will be presented before providing a relative comparison among those year by year. The DEA result is then analyzed and suggestions with regard to changes in local economic environment in near future are contributed.

• 한국시뮬레이션학회논문지
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• 제5권1호
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• pp.53-66
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• 1996

Container handling facilities in Korean ports have increased rapidly according to Korean industrialization and the worldwide containerization. Over 98% of total containers handles in Korean ports are handled in Puan ports. This paper presents the estimation method of annual container handling capacity of container terminals by the computer simulation models. Simulation models are developed utilizing SIMAN IV simulation package. Annual handling capacity of real container terminals such as BCTOC and PECT was estimated by the proposed simulation models. Also, Annual handling capaicty of planned or expected terminals in Puan port was estimated. The comparisons between container forecast demand and estimated handling capacity of Pusan port from 1996 through 2001 were made. It showed that Pusan port will have over two million TEU handling capacity shortage during that period and will face enormous port congestion. Lastly, mid term and long-term capacity expansion plansof container terminals in korean ports were discussed.