• 한국항해항만학회지
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• 제30권2호
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• pp.145-150
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• 2006

Recently we have seen a noticeable trend in ports to establish port clusters. Despite this trend, little research has actually been undertaken to fully define and analyse port clusters. A couple of exceptions have descriptively defined port clusters but the boundaries of port clusters are not apparent. Therefore, the aim of this paper is to define port clusters in terms of set theory and in particular look at them in terms of their distinct characteristics and system boundaries. The main concern of this paper is that there is a need to distinguish, from a system and a competition perspective, between port clusters, ports, maritime clusters and port ranges. This paper proposes a conceptual model relevant to the relationship among port clusters related assemblages and that has been applied to the north western europe region This model suggests six levels of competition that will help port authorities and government to develop appropriate policies and strategies for port operation and port industry.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2019년도 추계학술대회
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• pp.112-113
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• 2019

UN 산하의 국제해사기구(International Maritime Organization, IMO)는 2016년 10월 24일 열린 해양환경보호위원회 70차 회의에서 2020년부터 선박에서 사용되는 연료유에 포함된 황함유량 허용치를 기존 3.5%에서 0.5% 이하로 제한하기로 결정했다. 따라서 2020년 이후부터 전 세계를 항해하는 모든 선박은 연료유의 황 함유량을 0.5% 이하로 낮춰서 운항을 해야 한다. 지속가능한 경영을 위해서 국제적 환경규제에 대응하여 각 선사의 상황에 적합한 해결책을 강구하여야

• 한국레이저가공학회지
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• 제14권3호
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• pp.12-16
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• 2011

In automotive industry, because of the consideration of fuel economy, lightweight alloys have been adopted and are expected to be extensively used in the future. Magnesium alloys are among the promising materials, due to their lightweight and good mechanical properties. This study is related to the laser weldability of AZ31B magnesium alloy, an all-purpose wrought alloy with good strength and ductility. A 4kW Nd:YAG laser was used to join AZ31B sheet, and the effects of welding parameter on the quality of lap-welded joints were investigated. As a result of this study, the optimal condition was obtained, and the effect of gap distance was also revealed on the porosity control.

• 수산해양교육연구
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• 제22권1호
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• pp.91-98
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• 2010

물류산업은 세계의 모든 정부 및 국가기관에 의하여 최고로 인식되고 있는 전략적이고 경제적 이윤추구의 전 세계에 걸친 거대한 산업이다. 싱가포르는 물류산업이 가장 발달하고 최고로 바쁜 항만을 갖고 있는 국가 중의 하나이다. 싱가포르의 강점은 아시아에서 훌륭한 문화여건, 금융과 상업적인 클러스터, 통신 및 운송의 연결성을 가지고 있는 가장 세계화된 도시라는 점이다. 싱가포르는 우수한 물리적인 산업기반 시설의 장점에 의하여 자유경쟁의 이득을 향유하고 있다. 그렇지만 이러한 것들만으로는 싱가포르가 우리들의 경쟁자로서 앞서 있다고 확신하기에는 충분하질 않다. 싱가포르는 적은인구와 지지배후지의 부족 등으로 도전에 직면하고 있어서 배후지를 다른 국가로 이전하고 있다. 싱가포르는 세계 경제 속에서의 국제화 중심이 되거나, 남동아시아 성장에 참여하고 배후지의 결속을 증가시키는 선택을 해야 될 것이다. 따라서 이 논문에서는 싱가포르 물류산업의 전략적 발전을 분석하기 위하여 수리통계학적 방법을 적용하였다.

• 제어로봇시스템학회논문지
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• 제19권10호
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• pp.867-872
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• 2013

Many practical processes in industry have nonlinearities of some forms. One commonly encountered form is actuator saturation which can cause a detrimental effect known as integrator windup. Therefore, a strategy of attenuating the effects of integrator windup is required to guarantee the stability and performance of the overall control system. In this paper, optimal tuning of a PID (Proportional-Integral-Derivative) controller with an anti-windup scheme is presented to enhance the tracking performance of the PID control system in the presence of the actuator saturation. First, we investigate effective anti-windup schemes. Then, the parameters of both the PID controller and the anti-windup scheme are optimally tuned by an EA (Evolutionary Algorithm) such as the IAE (Integral of Absolute Error) is minimized. A set of simulation works on two high-order processes demonstrates the benefit of the proposed method.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2015년도 추계학술대회
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• pp.224-226
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• 2015

Outwardly, the people in the shipping industry are aware that multicultural working environments and conditions could have a strong influence on the operation of ships. With a lack of cultural awareness and foreign language skill of crew members on ships, there are lots of misunderstandings and miscommunications among (cross-cultural) crews. More and more maritime accidents are caused by human error in the world's oceans. Nevertheless the research on cultural diversity and human interaction on ships is still in its infancy. Due to the rapid change of the demographic make-up of crews, not only teaching and training technical skills for the crews, but also education in nontechnical skills such as cultural awareness, cultural sensitivity, intercultural competence is urgently needed. This study will deal with intercultural issues on ships. It aims to emphasize the necessity of intercultural training in MET.

• International Journal of Naval Architecture and Ocean Engineering
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• 제5권1호
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• pp.21-32
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• 2013

Marine transportation industry is undergoing a number of problems. Some of these problems are associated with conventional marine fuel-oils. Many researchers have showed that fuel-oil is considered as the main component that causes both environmental and economic problems, especially with the continuous rising of fuel cost. This paper investigates the capability of using natural gas and hydrogen as alternative fuel instead of diesel oil for marine gas turbine, the effect of the alternative fuel on gas turbine thermodynamic performance and the employed mathematical model. The results showed that since the natural gas is categorized as hydrocarbon fuel, the thermodynamic performance of the gas turbine cycle using the natural gas was found to be close to the diesel case performance. The gas turbine thermal efficiency was found to be 1% less in the case of hydrogen compared to the original case of diesel.

• 한국항해항만학회지
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• 제28권2호
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• pp.149-154
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• 2004

A linear power amplifier is particularly emphasized on the system using a linear modulations, such as 16QAM and QPSK with pulse shaping, because intermodulation distortion which causes adjacent channel interference and co-channel interference is mostly generated in a nonlinear power amplifier. In this paper, parameters of a linearization loop, such as an amplitude imbalance, a phase imbalance and a delay mismatch, are briefly analyzed to get a specific cancellation performance and linearization bandwidth Experimental results are presented for IMT-2000 frequency band The center frequency of the feedforward amplifier is 2140MHz with 60MHz bandwidth When the average output power of feedforward amplifier is 20 Watt, the intermodulation cancellation performance is more than 28dB. In this case, the output power of feedforward amplifier reduced 3.5dB because of extra delay line loss and coupling loss. The feedforward amplifier efficiency is more than 7% for multicarrier signals.

• 한국항해항만학회지
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• 제29권9호
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• pp.801-806
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• 2005

The world of container shipping and container terminal business is changing and container ports need to know what the changes are in order to plan how to respond. In particular, the container transport industry has noticed two major developments such as globalization and consolidation. The purpose of this paper is to review the current trend towards globalization and consolidation of container liner shipping and container terminal business. It also investigates the impact of these market developments on container ports and presents its implications for port development, management and operation, and port competition policy. According to the discussion of this paper a greater exercise of market power of container terminal operators will have negative impacts on international trade and national economy, especially port users, including container lines, exporters and importers. An empirical evidence on the exercise of market power is required to develop competition rules on market dominance at a national and international level. This paper suggests 'port coopetition' as a solution for smaller and regional container terminal operators to survive in a competitive business environment.

• Journal of Mechanical Science and Technology
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• 제19권12호
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• pp.2263-2269
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• 2005

The ship wave phenomena in the restricted waterway were investigated by a numerical analysis. The Euler and continuity equations were employed for the present study. The boundary fitted and moving grid system was adopted to enhance the computational efficiency. The convective terms in the governing equations and the kinematic free surface boundary condition were solved by the Constrained Interpolated Profile (CIP) algorithm in order to solve accurately wave heights in far field as well as near field. The advantage of the CIP method was verified by the comparison of the computed results by the CIP and the Maker and Cell (MAC) method. The free surface flow simulation around Wigley hull was performed and compared with the experiment for the sake of the validation of the numerical method. The present numerical scheme was applied to the free surface simulation for various canal sections in order to understand the effect of the sectional shape of waterways on the ship waves. The wave heights on the side wall and the shape of the wave patterns with their characteristics of flow are discussed.