• Journal of Korean Port Research
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• v.11 no.1
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• pp.1-11
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• 1997

The conventional methods of container forecasting is done through regression methods based on GNP growth trends and by other forecasting methods proposed by several authors. However these efforts prove to be inadequate with visible weakness and a more reasonable approach need to be determined. The succeeding sections elaborate the methodology and approach adopted. The results are then compared through a case study involving the forecast figures derived by the Pusan Port Authority and the values obtained by MRCS model introduced in this paper.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.2
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• pp.230-237
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• 2023

Due to the COVID-19 pandemic and climate change, shortages of essential commodities and resources continue to occur globally. To address this problem, trade volume demand suddenly increased, driving up the freight rate of container ships sharply. The size of container vessels progressively increased from 1,500 TEU (twenty-foot equivalent unit) in the 1960s to 24,400 TEU in 2021. As the improvement of container loading capacity is closely related to the enlargement of the lashing bridge structure, it is necessary to design a structure effective for good container securing and safe under the various external loads that occur during voyage. Major classification societies have recently issued structural-analysis-based guidelines to evaluate the structural safety of lashing bridges, but their acceptance criteria and evaluation methods are different, causing confusion among engineers during design. In this study, the strength change characteristics are summarized by variations in the main variables (modeling range, opening consideration, mesh size) likely to affect the results. Based on this result, the authors propose a reasonable structural-analysis-based evaluation that is expected to serve as a reference in the next revision of classification standards.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.4
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• pp.324-331
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• 2024

The height of large car and truck carriers from the keel to the wheel house is 44 ~ 46 m, and as the car-carriers increases in size, it exhibits the 'top heavy' characteristic, where the upper section is heavier than the lower section. This study aims to estimate the maximum outward heel angle of the Golden Ray car-carrier (G-ship) during turning maneuvers for accident investigation and the prevention of similar accidents. The theoretically calculated maximum outward heel is 7.5° (at 19 kn, rudder angle 35°) with a GM of +3.0 m or higher, and 16.7° with a GM of +1.85 m. Meanwhile the experimentally modified maximum outward heel is 10.5° (at 19 kn, rudder angle 35°) with a GM of +3.0 m or higher, and 23.3° with a GM of +1.85 m. The G-ship is maneuvered during an accident at a speed of 13 kn, at starboard rudder angle of 10° to 20°, it changes course from 038°(T) to 105°(T) based on the instructions of the on-board pilot. At this time, the maximum outward heel is estimated to be between 7.8° and 10.9° at the port side, which is 2.2 times higher than the normal outward heel. In the IS code, cargo ships are required to exhibit a minimum GoM of +0.15 m or more. The maneuvered G-ship exhibits a GoM of +1.72 m. It is not maneuvered because it fails to satisfy the international GoM criteria and because its GoM is insufficient to counteract the heeling moment during the maneuver. This study is performed based on accident-investigation results from the Korea Maritime Safety Tribunal and the USCG.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.4
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• pp.340-347
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• 2024

In this study, an expert survey was conducted using the Delphi technique to select items and indicators for evaluation before installing educational facilities in the marine fisheries safety field, in which the educational infrastructure gap between regions is wide. Seven indicators were selected as geographic, social, and administrative factors. In order to objectively evaluate each indicator, evaluation indicators that could be evaluated using public data such as the "Comprehensive National Balanced Development Information System" and "National Statistical Portal" were developed. The Analytic Hierarchy Process (AHP) method was applied to select the weight for each indicator, resulting in 10 most important influencing factors on the selection of the location of educational facilities of the Marine Fisheries Safety Education Facilities: the distribution of marine officers, access to high-speed railways, the number of small ships less than 5 tons, access to highways interchange, the distribution of fishing boats, the close relationship of related industries, the planned new port, the distribution of commercial ports, the number of marine leisure riders, and the availability of long-term land leases in local government councils. The location evaluation index of marine and fishery safety education facilities developed in this study can be used to evaluate each region using national public data, and has the advantage of enabling objective evaluation. Therefore, it is judged that this evaluation index can be used to verify the feasibility of installing marine fisheries safety education facilities as well as other marine-related facilities.

• Journal of Navigation and Port Research
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• v.37 no.6
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• pp.637-645
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• 2013

Masan bay with a semi-enclosed waters has serious water quality problems due to the low flow and river pollution load from land, and shows the vulnerable locational characteristics to storm surge. We are seeking the way of both operating disaster prevention facilities and water quality improvement measures in the bay. That is, the water was exchanged using the head difference occurred by operating disaster prevention facilities. The location of disaster prevention facilities was assumed to be in the inlet of the bay, in the vicinity of Machang bridge, and in the vicinity of Dot island and the operation time was assumed to be early morning hours(01~05) considering the number of shipping passage and annual tide, and spring tide of the largest head difference. In addition, the experiment case of water exchange including the in-outflow feeder pipe was tested. According to the simulation results, water exchange rate in all experiments has shown a steady increase. Water exchange rate of the whole of Masan bay in the case of present is 38.62%. The water exchange rate of the inside of Masan bay compared with the inlet of bay, appeared to be very low. Thus, we judged that the characteristics of semi-enclosed waters were well reproduced. On the results of the experiment of disaster prevention facilities and in-outflow feeder pipe, the case of the operation of disaster prevention facilities, water exchage rate is high compared with the case of present. And, the higer the operating frequency, the more water exchange is appeared. The cases of water exchange prevention facilities through the in-outflow feeder pipe caused by the head difference, also showed the higest improvement of the water quality. Compared with the south of Machang bridge, the effect of water exchange was better in the inlet of Masan bay and Dot island. On the other hand, the inlet of Masan bay is higer than Dot island as for water exchange of the whole of Masan bay, but opposite, water change rate including Masan inside was higher in the case of Dot island.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.5
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• pp.628-636
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• 2018

Because large buoys are mainly made of steel, they are heavy and vulnerable to corrosion by sea water. This makes buoy installation and maintenance difficult. Moreover, vessel collision accidents with buoys and damage to vessels due to the material of buoys (e.g., steel) are reported every year. Recently, light buoys adopting eco-friendly and lightweight materials have come into the spotlight in order to solve the previously-mentioned problems. In Korea, a new lightweight buoy with a 7-Nautical Mile lantern adopting expanded polypropylene (EPP) and aluminum to create a buoyant body and tower structure, respectively, was developed in 2017. When these light buoys are operated in the ocean, the visibility and angle of light from the lantern installed on the light buoys changes, which may cause them to function improperly. Therefore, research on the performance of light buoys is needed since the weight distribution and motion characteristics of these new buoys differ from conventional models. In this study, stability estimation and motion analyses for newly-developed buoys under various environmental conditions considering a mooring line were carried out using ANSYS AQWA. Numerical simulations for the estimation of wind and current loads were performed using commercial CFD software, Siemens STAR-CCM+, to increase the accuracy of motion analysis. By comparing the estimated maximum significant motions of the light buoys, it was found that waves and currents were more influential in the motion of the buoys. And, the estimated motions of the buoys became larger as the sea state became worser, which might be the reason that the peak frequencies of the wave spectra got closer to those of the buoys.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.6
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• pp.875-882
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• 2021

To minimize occupational noise induced hearing loss, it is recommended that workers should not be exposed to noise levels exceeding 85 dBA for over 8 h. In the present study, noise exposure levels were measured for seven workers based on their tasks on a training ship. The A-weighted noise exposure level (L_ex,24h) was measured by taking into account the A-weighted equivalent continuous sound level (L_Aeq,i), duration (h) and noise contribution (L_ex,24h,i) from the workers' locations. Results are thus obtained for different job categories as follows: officer group L_ex,24h=56.1 dB, navigation crew L_ex,24h=58.9 dB, navigation cadet L_ex,24h=62.0 dB, ship's cook L_ex,24h=64.3 dB, engine cadet L_ex,24h=91.1 dB, engineer L_ex,24h=91.1 dB, and engine crew L_ex,24h=95.1 dB. It was determined that the engineers, engine crews, and engine cadets in charge of machinery must wear hearing protection devices. By wearing hearing protection devices when working in highly noisy engine rooms, it is estimated that the noise expose levels could be reduced by the following amounts: engineer L_ex,24h=23.1 dB, engine Crew L_ex,24h=24.4 dB, and engine cadet L_ex,24h=21.5 dB. Moreover, if the no. 2 lecture room and mess room bottom plates in the cadets accommodations were improved to the 64 mm A-60-class floating plates, then further reductions are possible as follows: navigation cadet L_ex,24h=4.3 dB and engine cadet L_ex,24h=1.8 dB.

• Journal of National Security and Military Science
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• s.7
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• pp.155-231
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• 2009

Xu-Jing(徐競) an official of the Song(宋), a medieval Kingdom of China, wrote a book titled $\ll$Koryo Tu Jing(高麗圖經)$\gg$ which explains his travel to the Koryo as a member of diplomatic mission in 1123. $\ll$Koryo Tu Jing$\gg$ is the record of his personal experience in Koryo with many explanatory illustrations and especially contains 5 months' voyage record of his diplomatic fleet. His fleet set sail at a port located in the Ding Hai Xian(定海縣), Ming Zhou(明州) via a few islands of Koryo [Hyup Kye San(俠界山) , the Kun San Do(群山島) , the Ja Yon Do(紫燕島) , the Keup Su Mun(急水門) in Kang Hwa Gun(江華郡) and the Hap Gul(蛤窟) ] and finally arrived the Port Ye Song Hang(禮成港) . According to the Xu-Jing's record his fleet sailed the sea with the help of the favorable seaward winds and tides as the usual way of ancient sailing. The Xu- Jing's Fleet sailed the sea between the Mei Cen(梅岑), Ming Zhou(明州) of China and the Hyup Kye San(俠界山) of Koryo from about 5:00 a.m., May 24th(of the lunar calendar) to about 5:00 p.m., June 2nd. At this section, the average speed of the seaward winds was 19.45km/h and the average speed of the fleet which sailed only by the power of the winds was 6.29km/h. This means that 32.3% of the favorable seaward winds' speed was equal to the speed of the ancient fleet which sailed only by the power of the favorable seaward winds. The fleet sailed the sea between the Ja Yon Do(紫燕島) and the Keup Su Mun(急水門) from about 9:00 a.m., June 10th to about 1:00 p.m., the same day. At this section the fleet sailed by the power of tides in addition to the favorable seaward winds without oaring. The average speed of the winds was not different from that of former section and the average speed of the tides was 1.937km/h. And at this section the average speed of the fleet increased by 0.41km/h than that of the former section. This means that 21.1% of the speed of the tides was equal to the increased speed of the ancient fleet by virtue of the tides. The fleet sailed the sea between Keup Su Mun(急水門) and the Hap Gul(蛤窟) from about 1:00 p.m., June 10th to about 3:00 p.m., the same day. At this section, there were no seaward winds and the fleet sailed only by the powers of tides and oaring. And at this section, the tide increased the average speed of the fleet by 0.3114km/h and the fleet could sail at the speed of 4.3km/h. So we can conclude that the average speed of ancient fleet without any influences of the seaward winds and tides was 3.98 km/h. We can make use of the various sailing speeds of ancient fleets when judging their maritime activities. If we make use of the various sailing speeds of the ancient fleets as calculated in this article, we will be able to get various important informations about the certain ancient fleet's maritime maneuver. For example, we can infer the sailing routs of a certain fleet and the time when the fleet passed a certain spot by making use of the various sailing speeds of the ancient fleet. In this article I did not take account of the shapes of ships that consist of the ancient fleets and the sizes of the various ships and fleets. It was because that such factors would not change the foresaid conclusions seriously.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.6
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• pp.955-964
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• 2022

According to the statistics of maritime accidents statistics that have occurred in Korea over the past five years, maritime accidents caused by fishing boats have increased every year from 1,646 in 2016 to 2,100 in 2020. In particular, of the 378 capsizing accidents that have occurred in the past five years, 252 capsizing accidents of fishing boats account for a high proportion of 66.7%, therefore, it is urgent to come up with countermeasures. In this study, to determine the cause of the capsizing accident of fishing boat No. 66 poongsung, data such as stability and seawater inflow routes were collected, and the effects of waterproof, additional wood decks, and windbreakers on stability on were quantitatively analyzed. Additional decks, windbreakers, and waterproof installed in No. 66 poongsung cause initial list, deteriorate stability, and fail to meet fishing boat structural standards. In addition, it was analyzed that the stability was weakened due to the characteristics of the hull shape of No. 66 poongsung. To estimate the stability at the time of the accident, the stability at the time of the working in the fishing ground condition, amount of seawater inflow according to the change in sea conditions, hull oscillation situation, and change in stability due to the hull factor were calculated. As a result, the minimum GoM was satisfied at the time of working in the fishing ground, but it could not be restored at the maximum wave height of 4 m, and the minimum GoM was not satisfied at the maximum wave height of 4 m owing to the influence of seawater inflow and oscillation due to the hull list. However, the minimum GoM was satisfied if additional decks and windbreakers installation was excluded among the factors affecting the stability of No. 66 poongsung.

• Journal of Korean Port Research
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• v.12 no.1
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• pp.35-46
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• 1998

The CY can be said to function in various respect as a buffer zone between the maritime and overland inflow-outflow of container. The amount of storage area needed requires a very critical appraisal at pre-operational stage. A container terminal should be designed to handle and store containers in the most efficient and economic way possible. In order to achieve this aim it is necessary to figure out or forecast numbers and types of containers to be handled, CY area required, and internal handling systems to be adopted. This paper aims to calculate the CY area required for each container handling system in Mokpo New Port. The CY area required are directly dependent on the equipment being used and the storage demand. And also the CY area required depends on the dwell time. Furthermore, containers need to be segregated by destination, weight, class, FCL(full container load), LCL(less than container load), direction of travel, and sometimes by type and often by shipping line or service. Thus the full use of a storage area is not always possible as major unbalances and fluctuations in these flow occuring all the time. The calculating CY area must therefore be taken into account in terms of these operational factors. For solving such problem, all these factors have been applied to estimation of CY area in Mokpo New Port. The CY area required in Mokpo New Port was summarized in the conclusion section.