• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.971-976
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• 2004

The management of railroad structures is more difficult and complicate because there are many structures such as rail, bridge, tunnel, station, and so on. Therefore, LCC(Life Cycle Cost) analysis of railroad structures as public infrastructure must contain a maintenance cost as well as an initial cost in order to make a more effective management during the life cycle on the design phase. This paper presents a cost classification scheme considering user costs such as value of delayed time of passenger and freight. Also, in this study it is developed a probabilistic life cycle cost(PLCC) analysis model of railroad structures taking into account uncertainties and variations of input variables in order to analyze LCC. It may be stated that the model proposed in this study can greatly contribute to the making optimal decision, the estimate of the maintenance cost and the allocate of budget in the project of railroad structures.

• 한국철도학회논문집
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• 제12권3호
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• pp.348-356
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• 2009

본 연구의 목적은 SP 조사를 통해 화물별 DMT 효용함수 추정에 목적을 두고 있다. 추정된 효용함수는 화물별 OD 자료를 바탕으로 DMT 수요예측에 기초자료로 이용될 수 있다. 설문조사에서는 컨테이너와 위험물을 다루고 있는 업체와 철강운송 업체 중 연안 해운을 하고 있지 않은 운송업체를 대상으로 철도운송, 도로운송, DMT, 이렇게 세 가지의 선택대안을 사용하였다. 선택상황은 품목별/운송방향별로 가상 상황을 설정하였고 선정한 주요 화물품목은 컨테이너, 철강, 위험물이다. 또한 각각의 화물품목들에 대한 운송거리별 운송수단 선택모형은 통계적으로 다르지 않은 것으로 분석되었기 때문에 거리별(장거리, 중거리, 단거리)로 모형을 구축하지 않고 가장 물동량이 많은 장거 리(300km 이상)의 경우에 한해 화물별로 모형구축을 시도하였다. 사용할 속성변수로는 운송시간, 운송비용 그리고 신뢰성을 선정하였다. 수준 수는 일반적으로 가장 많이 사용되는 3수준으로 정하였으며 수준 값은 기준 값을 중심으로 +10%와 -20%로 정하였다.

• Journal of Korea Trade
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• 제25권4호
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• pp.17-36
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• 2021

Purpose - This study provides useful information to stakeholders by forecasting the tramp shipping market, which is a completely competitive market and has a huge fluctuation in freight rates due to low barriers to entry. Moreover, this study provides the most effective parameters for Baltic Dry Index (BDI) prediction and an optimal model by analyzing and comparing deep learning models such as the artificial neural network (ANN), recurrent neural network (RNN), and long short-term memory (LSTM). Design/methodology - This study uses various data models based on big data. The deep learning models considered are specialized for time series models. This study includes three perspectives to verify useful models in time series data by comparing prediction accuracy according to the selection of external variables and comparison between models. Findings - The BDI research reflecting the latest trends since 2015, using weekly data from 1995 to 2019 (25 years), is employed in this study. Additionally, we tried finding the best combination of BDI forecasts through the input of external factors such as supply, demand, raw materials, and economic aspects. Moreover, the combination of various unpredictable external variables and the fundamentals of supply and demand have sought to increase BDI prediction accuracy. Originality/value - Unlike previous studies, BDI forecasts reflect the latest stabilizing trends since 2015. Additionally, we look at the variation of the model's predictive accuracy according to the input of statistically validated variables. Moreover, we want to find the optimal model that minimizes the error value according to the parameter adjustment in the ANN model. Thus, this study helps future shipping stakeholders make decisions through BDI forecasts.

• Corrosion Science and Technology
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• 제10권4호
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• pp.136-142
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• 2011

Al alloys have been used widely for commercial and military ships in most ocean countries since mid-1950s, and the value as light metal with high mechanical strength has been proven. As the safety and fuel efficiency of Al ships have improved, she can carry more freight, sail faster and travel longer distances. Furthermore, in the shipbuilding industry, Al alloys are applied as structural materials for ships to various areas including the deck of luxurious cruises, battleships and leisure ships. In addition, Al alloys are being spotlighted as environmental-friendly material as they can be recycled even after end of lifespan. However, Al alloys for ships must be carefully selected after considering corrosion resistance, endurance, strength, and weldability in sea water environment. Al alloys to satisfy these conditions are used widely include 5000 series Al-Mg alloy and 6000 series Al-Mg-Si alloy. Thus, this study selected and evaluated the cavitation characteristics of the 5000 series Al alloys that are used in hulls that directly contact seawater and the 6000 Al alloys that are used in the upper structures of ships. Results of cavitation test with time, weightloss and cavitation rate of 5456-H116 showed the smallest damage among 5052-O, 5456-H116 and 6061-T6.

• The Journal of Asian Finance, Economics and Business
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• 제7권10호
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• pp.461-470
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• 2020

The objective of this research is to examine the factors affecting the decision-making of International Commercial Terms (Incoterms) of automotive parts manufacturers in Thailand. This mixed method study applied qualitative and quantitative research methods and utilized the analytical hierarchy process (AHP) to prioritize the significance of the factors. By an in-depth literature review and expert interview, four main criteria were identified. These criteria include Operating costs, Cooperation and bargaining power, Knowledge and understanding and Operation duration then main criteria divided into fifteen sub-criteria. The common Incoterms, Ex Works (EXW), Free On Board (FOB), Free Carrier (FCA), and Cost, Insurance and Freight (CIF), were determined as alternatives to the incoterms through a preliminary survey. The results revealed that the operating costs were the most important factor for the company. Moreover, it was discovered that this was consistent with the priority of the secondary factors, which included the annual budget for the transportation expenses and product value at one time. The respondents' perspective suggested that FCA was the most appropriate Incoterms for international trade for a company. The findings of this research suggest a hierarchy model for organizations to prioritize the significant factors in order to make a decision on the most appropriate Incoterms.

• The Korean Journal of Physiology
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• 제1권1호
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• pp.57-66
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• 1967

Cold $(0^{\circ}C)$ or warm $(25^{\circ}C)$ fresh and sea water were flooded into the lungs of rabbits through tracheal canule. Respiratory arrest ensued in 19.5 minutes in the warm fresh water flooded rabbits and was the longest survival time among the experimental groups. The survival times in the other groups were: 2.32 minutes in cold fresh water group, 2.75 minutes in .warm sea water group, and 4.57 minutes in cold sea water group. Cardiac output was measured by means of T-1824 dilution technique after 2 or 3 minutes of flooding in 27 rabbits. Blood pressure was observed by mercury manometer throughout the survival time in 40 rabbits. The following results were obtained. 1. Cardiac output in the warm fresh water flooded and sea water flooded animal was smaller than that of control rabbits. In the cold fresh water flooded animal cardiac output was greater than that of the control animal. 2. Time constants of T-1824 dilution curve of experimental group were elongated than the normal curve. 3. Central blood volume showed an increase in the fresh water group, a decrease in cold sea water group and no change in warm sea water group. 4. In all of the experimental groups arterial blood Pressure showed an abrupt and great variations after flooding of lungs and lasted about 30 seconds. Thereafter, arterial pressure remained at a plateau level until the sudden fall to zero and this was almost coincided with the time of respiratory arrest. The Plateau level of arterial Pressure in fresh water group was about 10 mmHg higher than the control value, and it was lower than the control value in warm sea water group. In cold sea water group the plateau was made up by fluctuations around the control value. 5. Osmosis of water through the lung alveolar membrane occured in all animals. Fresh water caused hemodilution and sea water caused hemoconcentration. 6. In sea water flooded animal more volume of water was recovered through the tracheal canule than the volume injected into trachea. This was interpreted as the consequence of the shift of water from plasma to alveolar sac. 7. Relative freight of lung was greater in fresh water group than sea water group. In all animal lung edema ensued. 8. The mechanisms of cardiac output variations were discussed.

• Journal of Korea Trade
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• 제24권6호
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• pp.115-134
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• 2020

Purpose - International trade leads to the international division of labor, improving the efficiency of the global economic system. Transport costs are a more serious barrier to international trade than customs tariffs. An increase in competition in the transport sector may thus lead to a reduction in transport costs. However, if a carrier's nationality significantly influences transport costs, simply adding more competing carriers of different nationalities would be ineffective. Therefore, it is necessary to establish national or regional carriers to influence competition and reduce transport costs. This study investigates this "nationality effect" by treating Hanjin Shipping's collapse as a natural experiment. Design/methodology - The theoretical basis of this study is the 3rd-degree price discrimination in container shipping market. By using the monthly data of container freight rates of Korea, China and Japan, this study shows the so-called Korea Premiums, which are the empirical counterparts of nationality effect in Korea container shipping market. For this empirical investigation, the structural model with state-space form is used and the dummy models are also estimated. In addition, because China has been also affected by the Hanjin's collapse, the China premiums are considered too. Findings - Compared with Japan's case, it is shown that there had been the so-called Korea premiums since the collapse of Hanjin Shipping. These results are robust from both the state-space model and dummy models. The time pattern of Korea premiums was consistent with the market evolution, especially the pattern of substitutability in container shipping markets. In addition, this paper shows the magnitude of Korea premiums. Originality/value - The argument of this study that the nationality effect can be interpreted as an extended concept of the home market effect is original, which is expected to evoke future research efforts. Further, the discussion on the shipping industrial policy from both horizontal and vertical aspects will provide the relevant policy makers with solid information, especially for the policy coordination in a global scale.

• 한국산학기술학회논문지
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• 제19권12호
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• pp.645-652
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• 2018

최근 한국이 OSJD(Organization for Cooperation of Railway) 정회원에 가입함에 따라 우리나라도 OSJD의 협약을 적용받을 수 있어 소프트웨어적으로는 대륙철도와 연결되었다고 볼 수 있다. 그러나 오랜 세월 각 주변국들의 철도시스템들이 개별적으로 개발되고 운용된 결과 하드웨어적으로는 제약이 있어 현 상태의 철도시스템의 기술적 상호운용성에 대한 진단이 필요하고 장기적으로 상호운용성을 향상시키기 위한 방안 또한 필요하다. 이에 본 연구에서는 현 상태의 대륙철도 국가들의 철도시스템의 기술적 상호운용성을 유럽에서 활용하였던 기술적 상호운용성 기준인 TSI(Technical Specifications for Interoperability)를 기준으로 각 국의 철도시스템을 분석하였다. 실제 특정구간의 열차운행을 가정한 열차의 운행모델을 바탕으로 필요한 인프라 벡터와 철도차량 벡터의 모델을 만들고 열차운행에 따른 인터페이스에 의해 발생하는 상호운용성 행렬을 바탕으로 상호운용성 지수인 IOP(Interoperability Of Percentage)를 계량화하였다. 부산에서 블라디보스톡까지 디젤기관차와 화차를 활용하여 운행할 경우 IOP값은 22.2%에 불과하여 상호운용성이 낮은 편이었다. 즉 77.8%의 상호운용성 제약요인이 존재하는 것이다. 이와 같은 제약요인들은 장기적으로 기술적 상호운용성을 높이는 방향으로 건설 및 제작되어야 대륙철도구간의 열차운행의 장애요인을 감축할 수 있으며 상호운용성이 100%인 대륙철도 노선을 만들어 운용효율성이 높은 철도가 될 것이다.

• 한국항만경제학회지
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• 제34권2호
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• pp.17-30
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• 2018

지역이 가진 특성과 자원을 그 지역의 핵심전략산업으로 연결하는 지역산업추진체계는 지역의 산업자원을 유기적 네트워크 형태로 확산시키고 있다. 충청권 항만 중에서 국제여객터미널과 부두가 완비된 곳은 서산 대산항이 유일하며 2018년 룽청시 룽옌항과 취항을 앞두고 있다. 본 연구는 지역산업발전을 위해 충청권에서 최초로 진행 중인 국제여객선 취항이 지역경제에 미치는 영향에 대해 2013년 지역산업연관표를 활용하여 충남지역 관광산업과 항만산업에 대한 파급효과를 분석하였고, 분석결과 관광산업과 관련하여 연간 생산유발 47,815백만원과 부가가치 유발 23,423백만원에 대한 효과가 있는 것으로 나타났으며, 항만산업에서는 컨테이너 화물 처리와 부가가치 수입을 합하여 12,567백만원의 효과가 나타나는 것으로 분석되었다. 현재 타 지역 한중 항로 국제여객선의 특성상 여객보다는 화물에 대한 의존도가 높은 편으로 서산에 국제여객선이 취항되면 우선 여객을 통한 관광에 따른 고용창출효과의 극대화를 위해 관광객 유치를 위한 전략적인 마케팅이 요구되며 수입화물과 수출화물의 균형을 유지하는 등 꾸준한 화물의 확보도 필요하다. 또한 더 큰 부가가치의 창출을 위해 다른 지역과의 신규항로 개설이나 취항횟수를 늘리는 등의 노력도 요구된다.

• 한국항해항만학회지
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• 제47권3호
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• pp.167-173
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• 2023

한국 경제에 근간이 되는 산업은 제조업이고, 그중 석유화학산업은 전량 원유를 수입하여 우리나라의 기술력으로 가공하여 재수출하는 전략적 성장 산업이다. 수많은 제조업의 원료가 되는 원유를 전량 해상운송을 통해 수입하는 우리나라는 변동성이 심한 유조선 운임 시장에 대해 기민하게 대응해야 한다. 유조선 운임 시장의 위기는 관련 해운회사의 위기에서 끝나지 않고 원유를 사용하는 산업에서부터 국민의 생활까지 영향을 미칠 수 있으므로, 본 연구에서 신호접근법을 활용한 조기경보모형을 제시했다. BDTI 운임지수를 활용하여 유조선 해운시장 위기를 정의하고, 38개의 거시경제, 금융, 원자재 지표 그리고 해운시장 데이터를 활용해 시차상관관계를 분석하여 유조선 해운시장 위기에 선행적으로 반응하는 종합선행지수를 도출했다. 연구 결과, 종합선행지수는 두 달 전 가장 높은 0.499의 시차상관계수 값을 가졌으며, 5개월 전부터 유의미한 상관계수 값을 나타냈다. QPS 값은 0.13으로 위기 예측에 대해 높은 정확성을 지니는 것으로 검증됐다. 더불어 기존의 다른 시계열 예측모형 연구들과 달리 본 연구는 경제 위기와 유조선 해운시장의 위기 간의 시차를 계량적으로 접근하여, 관련 해운산업 종사자들과 정책 입안자들에게 위기에 효과적으로 대처할 수 있는 전략의 기틀을 제공함에 의의가 있다.