• Journal of Fisheries and Marine Sciences Education
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• v.29 no.3
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• pp.665-676
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• 2017

Over the past several years, sea trade have increased traffic by ships which highlighted a problem of unwanted species invading the surrounding seas through ship's ballast water discharge. Maritime trade volume has continuously increased worldwide and the problem still exists. The respective countries are spending billions of dollars in an effort to clean up the contamination and prevent pollution. As part of an effort to solve marine environmental problem, BWM(Ballast Water Management) convention was adopted at a diplomatic conference on Feb. 13 2004. In order to comply harmoniously this convention by each country. This convention will be effective after 12 months from the date which 30 countries ratified accounting for more than 35% of the world merchant shipping volume. On Sep. 8 2016, Finland ratified this convention and effective condition was satisfied as 52 states and world merchant vessel fleet 35.1441%. Thus, after Sep. 8 2017, all existing vessels shall be equipped with BWTS(Ballast Water Treatment System) in accordance with D-2 Regulation, which physically handles ballast water from ballast water exchange system(D-1 Regulation). In this study, we analyzed in detail the optimal design method using the Risk Analysis and Evaluation technique which is mainly used in the manufacturing factory or the risky work site comparing with the traditional design concept method applying various criteria. The Risk Assessment Method is a series of processes for finding the Risk Factors in the design process, analyzing a probility of the accident and size of the accident and then quantifying the Risk Incidence and finally taking measures. In this study, this method was carried out for Electrolysis treatment type on DWT 180K Bulk Carrier using "HAZOP Study" method among various methods. In the Electrolysis type, 63 hazardous elements were identified.

• Journal of Navigation and Port Research
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• v.29 no.8 s.104
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• pp.741-746
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• 2005

This paper proposes a method for designing layout on the yard and evaluating alternative designs of the layout by applying simulation The design method is based on the concepts of the conventional port container terminal with yard layout. In general, yard design of the container terminal consists of the two major parts. One is to divide yard area between the number of sections and runs and the other is to decide the number of equipment including yard truck and yard crane. In the past days, this design was depended on the experience of the terminal operator and the reproduction of the conventional terminal layout because it is a very complex problem to be considering facilities and equipments. In this paper, we suggest a design method as a conceptual procedure used simulation method The number of sections and runs on yard area, the number of yard truck per container crane, and the number of yard crane per run are decided using simulation In addition, the traffic flow among blocks on yard layout is estimated in terms of rate.

• Journal of Distribution Science
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• v.17 no.10
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• pp.115-123
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• 2019

Purpose - The purpose of paper is to examine into corporate value of international physical distribution, which is closely related with company that is running business based on competitive power. It is good for company to gain a competitiveness throughout activities from international physical distribution, then it increases corporate value after all. Then it will be looked at how international physical distribution can influence competitiveness of company in terms of corporate value. Research design, data, and methodology - The research method to be described is first to identify concept of international physical distribution theoretically, including characteristics and structure, and then to review corporate value of international physical distribution to make company be competitive. As far as general landscape of international logistics is concerned, it is investigated into function and role of service provider, user and market situations. However, it is well proved that current market of international physical distribution is stable and bright, which means it is possible to take foreseeable future as well. Then company can share with corporate value of international physical distribution provided from logistics service provider. Results - To achieve corporate value throughout process of international physical distribution is strongly connected with competitive status of logistics service providers, those are carriers and infrastructures, and third party logistics providers. Especially in order to inquire into competitive aspects of international physical distribution in this paper, it is focused on trade volumes and overcapacity of global shipping market. Unlike it is used to be, more optimistic and positive situation has been shown since 5 years ago from the year of 2018, which means carriers make a business well, leading company to be more competitive. Conclusions - Corporate value of company in terms of international physical distribution is closely involved with competitive situations in the physically distribution, especially shipping market, which service providers can paly a key role in this regards. It can be estimated that the more market of international physical distribution works, the more competitiveness of companies increases. Ocean carriers in shipping market of international physical distribution are doing actively business well, and the corporate value can be materialized in favor of company.

• Journal of Navigation and Port Research
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• v.28 no.10 s.96
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• pp.891-897
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• 2004

This paper provided a simulation model for transport vehicles that carry container from the ship to yard block and vice versa at automated container terminal with a perpendicular yard layout. Usually, the efficiency of container terminal is evaluated by the productivity of container cranes at apron, and the stevedoring system for transport vehicles and yard cranes should be supported enough to improve productivity of container cranes. Especially, transport vehicle is very important factor in the productivity of container cranes and the performance of transport vehicles are changed according to the number and traveling type of vehicles. For these reason, a method that can estimate productivity of transport vehicle is required Finally, we developed the simulation model to analyze the productivity of transport vehicle and presented the productivity of container cranes for a varying operation of transport vehicles.

• Journal of Navigation and Port Research
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• v.36 no.10
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• pp.911-916
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• 2012

The purpose of this study is to review and suggest coastal shipping policies for introduction of WIG craft into domenstic passenger shipping market. Two Korean companies are leading in the development of WIG craft as an innovative sea transportation vehicle, and it is awaiting for commercialization. WIG craft is expected to be commercialized from coastal passenger market and we used AHP method to investigate the major factors and its' priority for smooth market entry. The results shows that priorities are on the WIG craft legislation, dock installation and operation, port state control, and pilot hiring and training, craft maintenance, and ship's certification in order.

• Composites Research
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• v.28 no.2
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• pp.58-64
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• 2015

The purpose of this paper is to suggest the effective equivalent finite element model for the impact limiter of a nuclear spent fuel shipping cask made of sandwich composite panels. The sandwich composite panels were composed of a metallic facesheet and a core material made of urethane foam, balsa wood and red wood, respectively. The effective equivalent finite element model for the impact limiter was proposed by comparing the results of low-velocity impact test of sandwich panels. An explicit finite element analysis based on LS-DYNA 3D was done in this study. The results showed that the solid elements were recommended to model the facesheet and core of sandwich panels for impact limiter compared to combination modeling method, in which the layered shell element for facesheet and solid element for core material are used. In particular, the solid element for balsa and red wood core materials should be modeled by the element elimination approach.

• Journal of Radiation Protection and Research
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• v.18 no.2
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• pp.47-59
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• 1993

The criticality of the shipping cask(KSC-7) for transportion of 7PWR spent fuel assemblies has been calculated and analysised on the basis of neutron transport theory. For criticality analysis, effects of the rod pitches, the fixed neutron absorbers(borated sus+boral) were considered. The effective multiplication factor has been calculated by KENO-Va, Mote Carlo method computer code, with the HANSEN-ROACH 16 group cross section set, which was made for personal computer system. The criticality for the KSC-7 cask was calculated in terms of the fresh fuel which was conservative for the aspects of nuclear critility. From the results of criticality analysis, the calculated Keff is proved to be lower than subcritical limit during normal transportation and under hypothetical accident condition. The maximum calculated criticalities of the KSC-7 were lower the safety criticality limit 1.0 recommended by US 10CFR71 both under normal and hypothetical accident condition. Also, to verify the KSC-7 criticality calculation results by using KENO-Va, it was carried out benchmark calculation with experimental data of B & W(Bobcock and Wilcox) company. From the 3s series of calculation of the KSC-7 cask and benchmark calculation, the cask was safely designed in nuclear criticality, respectively.

• Journal of Korean Society for Quality Management
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• v.47 no.3
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• pp.497-508
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• 2019

Purpose: The purpose of this study is to overcome limitations of conventional studies that to predict Baltic Dry Index (BDI). The study proposed applications of Artificial Neural Network (ANN) named Long Short-Term Memory (LSTM) to predict BDI. Methods: The BDI time-series prediction was carried out through eight variables related to the dry bulk market. The prediction was conducted in two steps. First, identifying the goodness of fitness for the BDI time-series of specific ANN models and determining the network structures to be used in the next step. While using ANN's generalization capability, the structures determined in the previous steps were used in the empirical prediction step, and the sliding-window method was applied to make a daily (one-day ahead) prediction. Results: At the empirical prediction step, it was possible to predict variable y(BDI time series) at point of time t by 8 variables (related to the dry bulk market) of x at point of time (t-1). LSTM, known to be good at learning over a long period of time, showed the best performance with higher predictive accuracy compared to Multi-Layer Perceptron (MLP) and Recurrent Neural Network (RNN). Conclusion: Applying this study to real business would require long-term predictions by applying more detailed forecasting techniques. I hope that the research can provide a point of reference in the dry bulk market, and furthermore in the decision-making and investment in the future of the shipping business as a whole.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.5
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• pp.574-583
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• 2021

Predicting shipping markets is an important issue. Such predictions form the basis for decisions on investment methods, fleet formation methods, freight rates, etc., which greatly affect the profits and survival of a company. To this end, in this study, we propose a shipping freight rate prediction model for container ships using gated recurrent units (GRUs) and long short-term memory structure. The target of our freight rate prediction is the China Container Freight Index (CCFI), and CCFI data from March 2003 to May 2020 were used for training. The CCFI after June 2020 was first predicted according to each model and then compared and analyzed with the actual CCFI. For the experimental model, a total of six models were designed according to the hyperparameter settings. Additionally, the ARIMA model was included in the experiment for performance comparison with the traditional analysis method. The optimal model was selected based on two evaluation methods. The first evaluation method selects the model with the smallest average value of the root mean square error (RMSE) obtained by repeating each model 10 times. The second method selects the model with the lowest RMSE in all experiments. The experimental results revealed not only the improved accuracy of the deep learning model compared to the traditional time series prediction model, ARIMA, but also the contribution in enhancing the risk management ability of freight fluctuations through deep learning models. On the contrary, in the event of sudden changes in freight owing to the effects of external factors such as the Covid-19 pandemic, the accuracy of the forecasting model reduced. The GRU1 model recorded the lowest RMSE (69.55, 49.35) in both evaluation methods, and it was selected as the optimal model.

• Journal of Navigation and Port Research
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• v.35 no.7
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• pp.605-611
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• 2011

In this paper, practical problems for current feeder service between Busan port and west coast of Japan were extracted through in depth interviews with Japanese feeder vessel companies, shippers, and port authority based upon which major criteria (elements) for improvement of the feeder network are structured in hierarchic order and weighed relative importance through AHP method. From the questionnaire answered by Korean and Japanese port users and experts the weights of criteria were calculated and the shipping service was ranked the first by both parties with 0.235 and 0.217, respectively. The port service and support system ranked the second and the third, whereas the port marketing was shown to be the lowest of all. Considering the overall weights, the increase in a port loading and unloading speed of port service was followed by provision of dedicated deck for feeder vessel of port facilities for Korean respondents. Therefore, speed up of the port operations and providing docks for feeder vessel are to be firstly provided for more efficient feeder operations, which would be the basis for the construction of optimal transportation network.