• Proceedings of KOSOMES biannual meeting
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• 2008.05a
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• pp.249-255
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• 2008

IOn 7th of Dec. 2007, large oil spill took place the seas off the Taean coast caused by the collision between VLCC Hebei Spirit and crane floating barge Samsung-1 and a lot of problems were revealed during response to the accident. The author, accordingly, examined to analyze the cause of this accident on the aspect of spill prevention and presented some preventive measures, such as strictness to the current standard for tug operation, expansion of VTS service area and transfer of the VTS responsibility to Korea Coast Guard, designation of appropriate anchorage per ship's type, cargo and visiting purpose, and special management for dangerous goods carriers.

• Journal of Fisheries and Marine Sciences Education
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• v.23 no.4
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• pp.642-647
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• 2011

In order to analyze the influence of floating marine debris (FMD) in the East China Sea (ECS), a sighting survey was conducted from July 1st to July 14th, 2009 navigating about 966 km using a training vessel "Kaya (1,737 ton)" of Pukyong National University. The sampled zones are divided into 5 transect by observation day during the survey days and again specified with 45 segments per unit hour on the survey routes. The results of distribution of FMD are as follows: 1. The quantities of FMD at the central China Sea(CE) and northern part of Taiwan(NT) were found as total mean of 90.8 ea/hr, 56.7 ea/hr, respectively, and also 36.8 ea/hr, western part of Kyushu district(WJ), 10.7 ea/hr, 8.0 ea/hr, western(OK1) and northern part(OK2) of Okinawa, respectively. 2. Temporal variation of FMD is represented by depicting the sinusoidal curve as shape as tide in CE and OK1. 3. The higher sea surface temperature (SST) is as likely as if Kuroshio current exists strongly, the less quantities are decreased. On the other hand, the coastal zone of ECS and near of Yellow Sea are increased by lower SST.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.1
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• pp.133-141
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• 2023

Accurate measurement of seafloor topography plays a crucial role in developing marine industries such as maritime safety, resource exploration, environmental protection, and coastal management. The seafloor topography is constructed using side scan sonar (SSS) and single beam echosounder (SBES) or multibeam echosounder (MBES), which transmit and receive ultrasound waves through a device attached to a marine survey vessel. However, the use of a sonar system is affected by noise pollution areas, and the single beam has a limited scope of application. At the same time, the multibeam is mainly applicable for depth observation. For these reasons, it is difficult to determine the boundaries and areas of seafloor topography. Therefore, this study proposes a method to improve the backscatter data of multibeam echosounder, which has a relationship with the seafloor quality, by using digital image processing to classify the shape of the underwater surface.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.21 no.4
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• pp.439-450
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• 2023

In this study, the impact load resulting from collision with the fuel rods of surrogate spent nuclear fuel (SNF) assemblies was measured during a rolling test based on an analysis of the data from surrogate SNF-loaded sea transportation tests. Unfortunately, during the sea transportation tests, excessive rolling motion occurred on the ship during the test, causing the assemblies to slip and collide with the canister. Hence, we designed and conducted a separate test to simulate rolling in sea transportation to determine whether such impact loads can occur under normal conditions of SNF transport, with the test conditions for the fuel assembly to slide within the basket experimentally determined. Rolling tests were conducted while varying the rolling angle and frequency to determine the angles and frequencies at which the assemblies experienced slippage. The test results show that slippage of SNF assemblies can occur at angles of approximately 14° or greater because of rolling motion, which can generate impact loads. However, this result exceeds the conditions under which a vessel can depart for coastal navigation, thus deviating from the normal conditions required for SNF transport. Consequently, it is not necessary to consider such loads when evaluating the integrity of SNFs under normal transportation conditions.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.57 no.4
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• pp.479-488
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• 2024

In recent years, changes in the fishing ground environment have led to reduced catches by fishermen at traditional fishing spots and increased operational costs related to vessel exploration, fuel, and labor. In this study, we developed a deep learning model to classify the fishing activities of drift gillnet fishing boats using AIS (automatic identification system) trajectory data. The proposed model integrates long short-term memory and 1-dimensional convolutional neural network layers to effectively distinguish between fishing (throwing and hauling) and non-fishing operations. Training on a dataset derived from AIS and validation against a subset of CCTV footage, the model achieved high accuracy, with a classification accuracy of 90% for fishing events. These results show that the model can be used effectively to monitor and manage fishing activities in coastal waters in real time.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.1
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• pp.19-29
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• 2022

The result of a questionnaire survey conducted on fishermen using coastal fish traps shows that fall accidents during trap dropping and pulling constitute the highest proportion of accidents at 42.1 %, whereas slipping accidents on the deck or stricture accidents to the body due to the trap winding device constitute 21.1 % each. In addition, 53.2 % of all surveyed subjects responded that trap pulling is the most dangerous task, followed by fish sorting 33.8 %, and trap dropping 9.1 %. As for the main items requested by fishermen for improving the trap winding device, 36.8 % indicated a method to easily lift the trap from the water to the work deck, and 31.6 % indicated a method to overcome the rope tension and prevent slip when pulling the trap to reduce the accidents. The small trap fishing vessel winding device proposed herein can increase the winding force by strengthening the rope contact area and friction coefficient via an appropriate contact angle between the driving roller of the winding device and the rope. When the contact angles between the driving roller and the rope are 1°, 5°, 9°, 14° and 19°, the rope tension showed a difference according to each contact angle. When the contact angle is 9°, the rope tension is the highest at 392.62 kgf. Based on these experimental results, a prototype winding device is manufactured, and 25 traps are installed on a rope with a total length of 100 m at 4 m intervals in the sea, and then the rope tension is measured during trap pulling. As a result, the rope tension increases rapidly at the initial stage of trap pulling and shows the highest value of 31.89 kgf, which subsequently decreases significantly. Therefore, it is appropriate to design the winding force of a small trap fishing vessel winding device based on the maximum tension value of the rope specified at the beginning of the trap pulling operation.

• Proceedings of KOSOMES biannual meeting
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• 2003.11a
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• pp.35-44
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• 2003

Considering possible legal and policy problems with regard to the Cheju Strait, a central issue is whether the Cheju Strait should be treated as Korean territorial sea or an international strait The claim that the strait is territorial sea has been based on the use of a straight baseline method of dermarcation With the use of straight baseline, Korea claims that the breadth of the Cheju Strait is only 20.7 miles at its narrowest point and therefore the strait becomes the territorial sea of Korea. The consideration cf marine pollution has weighed heavily in claiming the Cheju Strait as territorial sea. Pollution resulting from the accidents cf tankers caused by fire, collision, or stranding in the Cheju Strait and the Korea Strait would be enormous, affecting the entire coastal waters of the south coasts cf Korea's mainland and Japan's Tsushima Islands areas. Catastrophic pollution in the Cheju Strait could also come from the accidents cf large-size oil tankers passing through the Korea Strait from the Malacca Strait Although the Korean government considers the geographic and socioeconomic conditions sufficient to justify Korea's claim of the Cheju Strait as territorial sea, it believes that declaring it so would raise considerable legal conflicts with maritime states. In view of the legal difficulties and the need to meet the problems arising from the growing vessel traffic in the Cheju Strait, the sea lanes and traffic separation schemes may be considered an alternative to the internationalization of the Cheju Strait Even if the Korean government dose not do so, the regime of innocent passage should be applied to vessels passing through the Strait and should not suspend innocent passage through the Strait. Therefore, the Korean government needs to have a more legal, pragmatic, functional and managerial approach than a purely sovereign and selfish approach to the solution of legal matters of the Cheju strait For this purpose, the UN Convention on the Law of the Sea would serve as a guide and also self-restraint and cooperative approaches would become norms governing the resolution of the law of the sea issues in the Cheju Strait.

• Journal of Navigation and Port Research
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• v.31 no.6
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• pp.447-454
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• 2007

To assess the port development and maritime traffic environment, the future traffic volume has been estimated using the number of inbound and outbound vessel for a specific port. The estimation of future traffic volume should be considered as an important factor to establish the degree of fairway congestion, the determination of fairway width and the operational role. Until now, the number of in and out vessel for the port has been only estimated mainly, but the type and size of inbound and outbound ships are different depending on the port's characteristics. So, it is difficult to estimate the future traffic volume using the change of only one item. This paper calculates the future traffic volume using the marine traffic characteristic factors as the number of coastal ship and ocean-going ship, the size of ship and the change of cargo volume per a ship etc. And it compared with the results of Artificial Neural Network(ANN) for accurate identification of nonlinear system.

• Journal of Fisheries and Marine Sciences Education
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• v.20 no.3
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• pp.400-409
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• 2008

The purpose of this study is to examine annual changes of coastal fisheries production in the shore of Jeonbuk Province in Korea. The catch data of an experimental vessel that used dredge nets were used to study fish species and catch per unit of fishing effort carried out from April 2002 to November 2004. The total number of fish species caught in 2002 was 23, and 15 in 2004. Total number of individuals were 6,008 and their total weight was 376.38 kg in 2002. In 2004, total number of fishes was 2,469, and their weight was 211.99 kg. The annual changes in fisheries production in the western coast of Korea were also analyzed from 1990 to 2007. The total near shore fisheries products in Korea has been relatively stable around 1,4000,000 metric tons to 1,8000,000 tons during this period. Similarly the Chungnam Province's annual fish catch had steadily risen from about 51,187 tons in 1990 to 85,637 tons in 2007. However, Jeonbuk Province's annual fish catch declined dramatically at around 133, 000 tons in 1990 to 45,000 tons in 2007. In summery, while the overall Korea's fisheries production has been stable over the past decade, that of Jeonbuk Province suffered drastic decline in the period. This decline was reflected in the decreased number of fish species, total individuals, and total catch in surverys performed with an experimental vessel.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.41 no.4
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• pp.248-262
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• 2005

The purpose of this study was to identify the state of demersal fish resource catch by small trawlers, which live in the southern waters off Goheung. We investigated the results of catch of sample fishing vessels, and performed fishing experiments using the actual fishing operation vessels from early November in 2002 till end of October in 2003. The daily amount of catch per vessel of the 35 small trawlers selected as sample vessels was the highest in summer seasons(June and July) as 70kg and the lowest in winter seasons(January and February) as 45kg and Octopus minor occupied as 17 to 30kg nearly 30% of the total catch. Additionally the catch of Octopus minor per vessel, per dragging hour ranges 3 to 6kg, which is the highest in March and June and the low in January to February, April to May and September. In the fishing experiments using small trawler, during the study period, a total of 75 fish species were collected. The number of individuals by species consisted 58.2% in Shrimps, 17.8% in Fish, 2.3% in Cephalopod. Of these, Parapenaeopsis tenella was the highest in 29.2%, Squilla oratoria and Crangon hakodatel was 14.6% respectively and Octopus minor was 0.2% of the total number of individuals. As far as the appearance number of individuals by month was concerned, February was the highest and then May, April and June followed in order, and October showed the lowest. Additionally the monthly catch per dragging was the lowest in December to January as 20kg and the highest in July as 160kg. Specially, Octopus minor was caught throughout the year regardless of season and the catch was the highest at the period from March to June. When looking into the body mean length of dominant fishes caught, we could observe the followings; Trachurus japonicus 8.9cm, Cynoglossus robustus 10.8cm, Muraenesox cinereus 15.3cm, Setipinna taty 10.3cm, Amblchaeturichfhys hexanema 9.3 cm and Collichthys niveatus 8.9cm, most of which were in their immaturity when they were caught.