• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.2
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• pp.153-159
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• 2016

Gwangyang traffic safety designated area is composed of 3 fairways (Deep water fairway, inbound fairway, and outbound fairway). However, inbound vessels can't use this passage because of Samyeo rock and artificial fishing banks in inbound route. The problem with the rocks and artificial fishing banks has been raised by ship navigators and authorities of the port. This research is about the safety evaluation and management plan of the passage, and we conducted maritime traffic simulation using a model based on a ship operator risks. As a result, assuming that future marine traffic volume is the same as the present, and if the ship operators use 3 fairways and not two, it showed risk reduction of 46.4 % (vessels over 50,000 DWT using DW route) and 57.1 % (vessels over 10,000 DWT using DW route). Also, in a traffic volume condition which is the same as the present, to induce vessels over 50,000 DWT to use DW route is effective in mitigating of risks. Meanwhile, in a condition which increased the traffic volume by 150 %, it is more effective to induce vessels to use DW route. This research is the result of analysis using the model based on ship operator risks, and not cost-effectiveness analysis on the removal of Samyeo rock and artifical fishing banks. This research is expected to be used on setting up the sea route and management plan (particularly, restriction on passing DW route).

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.1
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• pp.82-89
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• 2016

In this study, we proposed a pier of pontoon-type, "Very Large Floating Structure" (VLFS), with the length of 500m, breadth of 200 m and height of 2 m in Yeosu domestic port. Since this structure ought to endure wave loads for long periods at sea, it is essential to analyze the wave response characteristics. Direct-method is used to analyze the fluid-structure problem and the coupled motion of equation is used to obtain response results. The structural part is calculated by using finite element method (FEM) and the fluid part is analyzed by using boundary element method (BEM). Dynamic responses caused by the elastic deformation and rigid motion of structure are analyzed by numerical calculation. To investigate response characteristics of the pier in regular waves, several factors such as the wavelength, water depth, wave direction and flexural rigidity of structure are considered. As a result, wave response of pier changed at the point of $L/{\lambda}$ 1.5 and represented the torsional phenomenon according to the various incident waves. And the responses showed increasing tendency as the water depths increase at the incident point in case of $L/{\lambda}=8.0$ and peak point of vertical displacement amplitude moved from side to side as the flexural rigidity of structure changes.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.6
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• pp.637-645
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• 2018

This study analyzes the problem of lack of anchorage caused by some anchorage closed and suggests ways to improve Masan anchorage. For this, we established the evaluation criteria, and analysed the anchorage operating rate during 5 years after estimating the capacity of barge, and suggested improvement plan after appropriateness assessment of anchorage capacity, finally verified the anchorage improvement plan. As a result of study, it is analyzed that the Masan A-2, A-4, A-6 anchorage needs to expand the anchorage due to excess the anchorage assessment criteria of 60 %. So, in order to improve the Masan anchorage, we suggested the improvement plan that extended 1.8 times by the group designated anchorage, according to integrating the A-2, A-4, A-6 anchorage and anchorage dwell time and ship type. And, the result of verification improvement plan, it is analyzed that meet the assessment criteria since decreasing the anchorage operating rate by 1/2 compared to the existing one, does not act as a risk factor in terms of maritime traffic.

• Journal of Fisheries and Marine Sciences Education
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• v.29 no.1
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• pp.201-208
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• 2017

The major cause of the marine accidents is the collision with a moving object such as ship as well as the fixed object such as breakwater. Therefore, the most effective way to reduce the maritime ship accidents is the prevention of collision. In order to decrease the collision, it is principle that the navigation officer promptly judges the dangerous condition and makes the quick response. The ship does not allow any object or other ships approaching its surrounded area called ship area so that it prevents the collision. Generally, the ship which has high speed or poor maneuvering capability shall be managed from the distance so that the other ship does not invade its ship domains(watching distance, blocking distance). Accordingly, this study sets the navigational risk assessment model by applying ship dynamic domain and collision judgement method considered ship length, speed and navigational capability. It also reviewed the validity of the model and evaluated the perilous water way (Maenggol Channel) and a curved route near Maenggol Channel. As a result, in case of a ship with 100m in length passing Maenggol Channel, it represented "warning" level before 1.5nm to the entry, "dangerous"level 0.75nm before to it and "very dangerous" level 0.5nm before to it and then "dangerous"level again up to the entry. Applying to the curved route also showed the same results as the Narrow Channel or Maenggol Channel. This analysis highly matched with the actual navigation results. In the future, this model will be useful for coastal navigation safety chart development and safety evaluation for route or port development. It also allows to evaluate the dangerous route or the best route by applying the result into ECDIS so that it will finally help to reduce the marine accidents. Eventually the model will be effective for the marine traffic simulation evaluation forced by Maritime Traffic Safety Act.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.3 no.3
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• pp.170-174
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• 1998

The water quality of offshore waters around the Korean coast was evaluated by bioassay using gametes, embryoss and early development systems of a sea urchin species Hemicentrotus pulcherrimus. The results show that despite the inflows of several river systems, the west coast maintain the grade II water. This is thought to be due to the decrease in pollutant input resulting from the purification of inflow rivers (e.g., the control of waste water discharge and the construction of sewage treatment facilities), and the dilution of pollutants by a strong tidal mixing with a large difference between the ebb and flood tides. However, Asan, Hampyong and Chonsu bays, where circulations of water are relatively poor, and the Kunsan and Mokpo harbors which are influenced by pollutants from neighboring cities have shown the grade III water. The south coast has maintain the grade II or III because developments of sea urchins were moderately or strongly inhibited. Also, Kangjin, Duekryang, Kwangyang, Masan, and Jinhae bays where water circulations are relatively poor, show the grade III water, with strong inhibitions of the early development of sea urchins. The east coast has maintained the grade I and II due to monotonous coastlines and smooth circulation of sea water. However, Chongcho Lake shows the worst water quality due to the breakwater which is constructed to maintain port functions.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.25 no.4
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• pp.191-199
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• 2013

It is estimated and analyzed that the design wave height and the confidence interval (hereafter CI) according to the return period using the fourteen-year wave data obtained at Pusan New Port. The functions used in the extreme value analysis are the Gumbel function, the Weibull function, and the Kernel function. The CI of the estimated wave heights was predicted using one of the Monte-Carlo simulation methods, the Bootstrap method. The analysis results of the estimated CI of the design wave height indicate that over 150 years of data is necessary in order to satisfy an approximately ${\pm}$10% CI. Also, estimating the number of practically possible data to be around 25~50, the allowable error was found to be approximately ${\pm}$16~22% for Type I PDF and ${\pm}$18~24% for Type III PDF. Whereas, the Kernel distribution method, a typical non-parametric method, shows that the CI of the method is below 40% in comparison with the CI of the other methods and the estimated design wave height is 1.2~1.6 m lower than that of the other methods.

• Journal of fish pathology
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• v.22 no.1
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• pp.67-73
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• 2009

It was examined whether the common belief that "cultured puffer fishes do not contain tetrodotoxin (TTX)", the major lethal substance that accidently causes death in consumers of those fishes, is true in river puffer fish Takifugu obscurus. In mouse bioassay, lethal levels of toxins were detected in the ranks: gonad>liver>intestine>muscle>skin in wild puffer fish. In contrast, no mortality occurred in the mouse bioassay on cultured fish. However, there were sleepiness, sluggish behavior, and hind limb paralysis with the tissue extracts of cultured fish suggesting the presence of TTX or other similarly acting toxins. An attempt to confirm the presence of TTX in cultured fish with high performance liquid chromatography (HPLC) was not very successful. The results suggest possible existence of TTX toxins or similarly acting toxins.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.1
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• pp.47-55
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• 2017

As preliminary work for the establishment of a harmonized ship hand signal standard, this paper explores the availability of hand signals as a means of shipboard work communication and considers the validity of standardization. Prior to the feasibility study, shipboard work activities that use hand signals were classified based only on ship safety managers' arbitrary decisions. This survey was carried out to measure shipboard workers' willingness to communicate with hand signals and their preferences regarding the institutional standardization of a hand signal framework if they engage in activities classified as relevant. The results of statistical analysis (a t-test and correlation analysis) showed that respondents are willing to accept harmonized hand signals regardless of both their work type (crew/safety supervisors) and work department (deck/engine room) under working situations where hand signals are an available means of communication. In addition, there was a significant difference in the extent of shipboard workers' frequency of hand signal usages between each type of work activity, indicating a significant positive (+) correlation between frequency of usage and preference for standardization. Finally, it was concluded that shipboard work communication would be effectively improved if a follow-up study is carried out to establish prioritized harmonized hand signal standards for port-related work activities, such as crane operation, windlass/winch operation, line movement/delivery and cargo hold operations.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.3
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• pp.227-233
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• 2011

Korea coastal area is highly potential dangerous zone of marine accident due to frequent ship's encounters. VTS center can't identify ship's information because of beyond VHF range. It is also difficult of us to efficiently manage vessel traffic beyond VTS control area, so that it can't prevent marine accident. Presently, korean government is conducting maritime traffic safety assessment according to enlargement of harbor & development of new port but do not have the system which provide danger of information depending on maritime traffic environment with real time. So it is necessary to develop evaluation index which can assess sea risk through the evaluation of maritime traffic environment. In this paper, on the basis of vessel navigator's risk consciousness, we carried out survey & statistical analysis vessel navigator's subjective risk depending on the LOA, crossing situation($045^{\circ}$, $090^{\circ}$, $135^{\circ}$), overtaking, head-on situation, encountering vessel's side, within or outside harbor, speed with other vessel(ex. same, fast or slow), speed difference with other vessel and distance with other vessel & propose basic expression to develop maritime traffic safety evaluation model. And by using this model, we can confirm that this proposing expression is suitable for domestic maritime traffic environment.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.5
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• pp.535-541
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• 2019

The purpose of this study was to investigate the possibility of fishery in offshore wind farms and evaluate the risk linked to the presence of turbines and submarine cables in these areas. With this objective, we studied an offshore wind farm in the Southwest Sea and the current state of vessels in the surrounding National Fishing Port. The risk assessment criteria for 22 fishing gears and methods were set by referring to the fishing boats; thereafter, the risk was assessed by experts. The fishing gears and methods that could be safely operated (i.e., associated with low risk) in the offshore wind farm were: single-line fishing, jigging, and the anchovy lift net. The risk was normal so that it is possible to operate, but the fishing gears and methods that need attention are: the set long line, drifting long line, troll line, squid rip hook, octopus pot, webfoot octopus pot, coastal fish pot, stow net on stake, winged stow net, stationary gill net, and drift gill net. Moreover, the fishing gears and methods difficult to operate in the of shore wind farm (i.e., associated with high risk) were: the dredge, beam trawl, and purse seine. Finally, those associated with very high risk and that should not be allowed in offshore wind farms were: the stow net, anchovy drag net, otter trawl, Danish seine, and bottom pair trawl.