• 품질경영학회지
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• 제49권4호
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• pp.467-482
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• 2021

Purpose: The main theme of this study is to determine the optimal control limit of conditional variance investigation by mathematical approach. According to the determination approach of control limit presented in this study, it is possible with only one parameter to calculate the control limit necessary for budgeting control system or standard costing system, in which the limit could not be set in advance, that's why it has the advantage of high practical application. Methods: This study followed the analytical methodology in terms of the decision model of information economics, Bayesian probability theory and Taguchi's quality loss function concept. Results: The function suggested by this study is as follows; ${\delta}{\leq}\frac{3}{2}(k+1)+\frac{2}{\frac{3}{2}(k+1)+\sqrt{\{\frac{3}{2}(k+1)\}^2}+4$ Conclusion: The results of this study will be able to contribute not only in practice of variance investigation requiring in the standard costing and budgeting system, but also in all fields dealing with variance investigation differences, for example, intangible services quality control that are difficult to specify tolerances (control limit) unlike tangible product, and internal information system audits where materiality standards cannot be specified unlike external accounting audits.

• 동아시아경상학회지
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• 제10권2호
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• pp.55-69
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• 2022

Purpose - This study is a study to investigate the problem of the selection of means of transportation in international logistics by studying the basics of logistics activities, selection factors of transportation methods, and multimodal transportation. Research design, data, methodology - This study is composed of 5 chapters through literature study. Chapter 1 describes the functions and transportation system of international logistics, Chapter 2 selects transportation, Chapter 3 deals with maritime transportation and multimodal transportation, Chapter 4 describes multimodal transportation in terms of customer service, Chapter 5 addresses the implications and conclusions. Results - When looking at the problem of selecting a means of transportation, it is important that the parties involved in the transportation choose which means of transportation for their convenience and profit during the transportation process. Here, there will be factors to consider, including transportation cost, when selecting a means of transportation, and each means of transportation may have characteristics or advantages and disadvantages. Considering all these points, the adoption of multimodal transportation from a customer service point of view may be the answer. Conclusions - This study pays attention to the academic understanding related to the selection of means of transportation and to how usefully this thesis can be used in the selection of transportation related persons, especially shippers, from a practical level.

• Journal of Korea Trade
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• 제24권2호
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• pp.68-82
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• 2020

Purpose - This study investigates the impact of inland port development in China on the promotion of bilateral trade flows between China and South Korea. Design/methodology - The probable association between the establishment of inland ports and Sino-Korea trade was estimated using gravity models. In this regards, two sets of data were collected. The first dataset consists of the baseline variables of a gravity model, while the second one includes variables of logistics infrastructure development. The indicators of logistics infrastructure development include inland ports, the amount of government expenditure on transport infrastructure, the lengths of roads and railways, the number of trucks and the number of logistics industry workforce. Findings - The results show that inland port development has a positive impact on facilitating bilateral trade between China and South Korea. However, the positive association holds only for Chinese regions with a large trade volume and a proximity to seaports. In other regions, the impact of inland ports is not statistically significant. Originality/value - To the best knowledge of the authors, this study is the first attempt to explore the economic impact of inland ports in China. In addition, the findings in this paper provide both policy and managerial implications for the future development of inland ports, such as the strategic location of inland ports and integrated intermodal operations.

• The Journal of Asian Finance, Economics and Business
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• 제9권1호
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• pp.409-422
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• 2022

The purpose of this paper is to explore how the country-of-origin image mediates the effect of national stereotypes along two dimensions of perceived competence and warmth, on consumers' consumption behaviors, especially in today's environment, the capricious COVID-19 and the deepening and expanding "The Belt and Road" initiative. Research design, data, and methodology: After collecting 1500 primary data from twelve countries along the 21^st - Century Maritime Silk Road, this paper conducts ANOVA and SEM in SPSS25.0 and AMOS 24.0 separately to analyze measurements, structural models, and hypotheses via using 1277 final samples. The mediation results illustrate the asymmetric dominance of the two dimensions of national stereotypes, indicating that the country-of-origin image shows the complementary mediation in the effect of perceived competence on purchase intention; whereas, the country-of-origin image holds the indirect-only mediation in the impact of perceived warmth on purchase intention. The results of the moderation show that the effect of country-of-origin image on purchase intention is more significant for consumers who perceive COVID-19 in China to be of lesser severity than those who believe it to be of higher severity. Based on the paper's results, some implications for practice and theory are highlighted.

• 한국항만경제학회지
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• 제33권2호
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• pp.83-96
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• 2017

지구 온난화에 대처하는 일환으로 신재생에너지 가운데 세계 각국은 해상풍력단지 개발에 투자를 집중하고 있다. 그러나 해상풍력단지 개발은 해상에서의 구조물 운송, 설치 등의 해상작업이 요구됨에 따라 투자비용이 육상풍력단지 보다 높은 단점이 있다. 특히 해상기상 여건으로 인한 설치기간 지연은 해상풍력단지 운영의 경제성에도 영향을 끼치는 요소이다. 따라서 본 연구에서는 국내 해상의 기상여건을 고려하여 해상풍력단지 조성의 최적 일정계획을 거시적 측면에서 분석하고자 하였다. 이를 위해 수리적 모델을 개발하였고, 이를 이용하여 국내 서남해안 2.5GW 해상풍력단지 조성사업에 적용하였다. 해상 기상여건은 기상청의 자료를 활용하였고, 모델에 사용된 입력 자료는 해외의 선행 사례를 바탕으로 현실성을 최대한 반영하고자 하였다. 그 결과 해상풍력터빈 35기를 설치하는데 6개월이 소요되는 것으로 분석되었다. 특히 겨울을 피하여 작업하는 것이 비용을 최소화할 수 있는 것으로 분석되었다.

• 대한조선학회논문집
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• 제56권1호
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• pp.58-65
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• 2019

The stability, reliability and efficiency of a smart ship are important issues as the interest in an autonomous ship has recently been high. An automatic collision avoidance system is an essential function of an autonomous ship. This system detects the possibility of collision and automatically takes avoidance actions in consideration of economy and safety. In order to construct an automatic collision avoidance system using reinforcement learning, in this work, the sequential decision problem of ship collision is mathematically formulated through a Markov Decision Process (MDP). A reinforcement learning environment is constructed based on the ship maneuvering equations, and then the three key components (state, action, and reward) of MDP are defined. The state uses parameters of the relationship between own-ship and target-ship, the action is the vertical distance away from the target course, and the reward is defined as a function considering safety and economics. In order to solve the sequential decision problem, the Deep Deterministic Policy Gradient (DDPG) algorithm which can express continuous action space and search an optimal action policy is utilized. The collision avoidance system is then tested assuming the $90^{\circ}$intersection encounter situation and yields a satisfactory result.

• Journal of Korea Trade
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• 제26권7호
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• pp.127-144
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• 2022

Purpose - This study aimed to analyze the dynamic effects of progress in globalization on firm performance by employing individual companies' financial statement datasets. Design/methodology - The analysis leveraged the variables of operating revenue (OPRE) and pre-tax profit and loss (PLBT) as measurement variables for firm performance over 2011-2019. As a proxy variable for globalization, the trade index, a subordinate indicator of the KOF Globalization Index, was used. Through panel regression analysis, the relationship among those variables was ascertained, and the local projection (LP) method was subsequently utilized to identify dynamic effects. A subsample analysis was further performed by classifying companies based on their sizes and industries to determine the differential effects of globalization on each group. Findings - The panel regression analysis derived positive effects of an increasing degree of globalization on OPRE of Korea maritime and fishery firms. However, the impulse response functions, obtained from the LP, showed that in the short run, globalization affects PLBT negatively but in the long run, it gradually converted into a positive effect. In addition, according to the subsample analysis based on company size, the effects of globalization on OPRE became greater as each company became larger. Moreover, the industry-based analysis showed heterogeneous effects, depending on the industries in which the maritime and fishery companies operated. Originality/value - The analysis of the dynamic effects of globalization on firm performance, which revealed that the effects vary depending on the time points, is the important contribution of this study. The results also suggest that the effects of globalization vary depending on the company size and industry.

• 농업과학연구
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• 제48권4호
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• pp.815-829
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• 2021

The purpose of this study is to construct a flatfish outlook model that is consistent with the "Fisheries outlook" monthly publication of the fisheries outlook center of the Korea Maritime Institute (KMI). In particular, it was designed as a partial equilibrium model limited to flatfish items, but a model was constructed with a dynamic ecological equation model (DEEM) system, considering biological breeding and shipping times. Due to limited amounts of monthly data, the market equilibrium price was calculated using a recursive model method as the inverse demand. The main research results and implications are as follows. As a result of estimating young fish inventory levels, the coefficient of the young fish inventory in the previous period was estimated to be 0.03, which was not statistically significant. Because there is distinct seasonality, when estimating the breeding outcomes, the elasticity of breeding in the previous period was found to exceed 0.7, and it increased more as the weight of the fish increased, in addition, the shipment coefficient gradually increased as the weight increased, which means that as the fish weight increased, the shipment compared to the breeding volume increased. When estimating shipments, the elasticity of breeding in previous period was estimated to respond elastically as the weight increases. The price flexibility coefficient of the total supply was inelastically estimated to be -0.19. Finally, according to a model predictive power test, the Theil U1 was estimated to be very low for all of the predictors, indicating excellent predictive power.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2022년도 추계학술대회
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• pp.296-297
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• 2022

스마트 항만은 IoT, 빅데이타, AI, 블록체인 등의 디지털 기술을 바탕으로 구축된 항만을 말하며, 항만의 유일한 생존 수단으로서 시·공간 및 자원의 낭비를 최소화하는 항만을 말한다. 지속가능성(Sustainability)이란 '인간이 삶의 터전으로 삼는 환경과 생태계 또는 공공으로 이용하는 자원 따위를 계속해서 사용할 수 있는 환경적 또는 경제, 사회적 특성'을 말하는 것으로 생태계가 환경 파괴 없이 현재의 다양성과 생산성을 미래에도 유지할 수 있도록 하는 '미래 유지가능성'의 의미를 담고 있다. 4차 산업 혁명을 맞이하여 전 세계적으로 스마트 항만 구축과 지속가능성에 대한 관심과 실현이 활발하게 진행되고 있는 상황이다. 본 연구에서는 지속가능한 스마트 항만의 핵심요소인ESG(Enviornment, Social, Governance) 영역의 핵심 지표를 개발하고

• 자원ㆍ환경경제연구
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• 제32권1호
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• pp.27-46
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• 2023

본 연구는 차분연료배분모형을 이용하여 수송부문에서의 연료 간 대체성을 추정하고, 연료 간 대체에 따른 이산화탄소 배출효과를 살펴본다. 분석결과를 정리하면, 첫째, 수송부문은 경유에 대한 의존도가 매우 높아 디비지아 탄력성이 가장 큰 것으로 나타났다. 둘째, 연료별 자기가격탄력성은 모두 음(-)의 값을 보였으며, 경유의 자체가격탄력성이 휘발유와 LPG에 비해 상대적으로 낮은 것으로 나타났다. 셋째, 휘발유와 경유, 휘발유와 전기, 경유와 LPG는 대체관계를 보였으며, 경유와 전기는 보완관계를 갖는 것으로 나타났다. 넷째, 연료별 대체성과 배출계수를 이용한 결과, 바이오디젤을 경유에 혼합하는 경우 이산화탄소 감축 효과가 있으나, 주로 연료별 가격 변화에 따른 연료 간 대체가 이산화탄소 배출을 결정짓는 것으로 나타났다.