• Journal of the Korean Institute of Navigation
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• v.18 no.1
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• pp.23-30
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• 1994

By use of the Climatological Report(1982~1991) and the Marine Casualty Report(1982`1992), marine casualties caused by meteorological factors and climatic characteristics along Korean coast were analysed. Marine casualty by meteorological factors can be classified into three kinds such as collision, aground and sinking. On the whole collision was mainly caused by dense fog and heavy precipitation, and aground and sinking was caused by strong wind and high sea. As results of analysis of the distribution of wind, fog and precipitation at major ports in Korea, climatic characteristics along Korean coast are as follows. in the eastern coast, wind was relatively weak and fog was not so frequently formed, while strong wind blew all the year round and fog appeared from April to August in Ulleung Island. In the southern coast, the wind was strong in both winter and summer, fog formed frequently in late spring through mid-summer and heavy precipitation was in summer. Typhoon affecting Korea was usually passing this area to the East Sea. In the western coast, strong wind was prevailing in winter at southern region and fog was formed very frequently throughout the year.

• Journal of the Korean Society of Marine Environment & Safety
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• v.2 no.S1
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• pp.63-73
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• 1996

The assesment of the safety of ship's transit in a curved narrow channl consists of the maneuvering safety determined by the chance of running aground, the maneuvering difficulty determined by shop's workload, and shiphandler's subjective evaluation. In this study to examine the correlation between shiphandler's subjectice evaluation and the maneuvering risk, the real-time and full-mission shiphandling simulator in the Korean Marine Training & Research Institutes(KMTRI) was utilized. In the conning bridge of the shiphandling simulator, 50 experienced masters conducted masters conducted the modeled vessel of 60,000 deadweight tonnage along the designed channel under 3 different envrinmental conditions. The findings were as follows: (1) The frequencies of stress levels, work difficulties, vessel controllability and overall workload of shiphandlers are similar irrespective of environmental conditions and they are able to be represented as shiphandler's subjective evaluation. (2) It is possible to assess and analyze theoretically the correlation between the shiphandler's subjective ecaluation and maneuvering risk each environmental cindition by quantifying the data obtioned from the tests. The results are as follows: ① As the degree of maneuvering risk increases, the shiphandler's subjective evaluation increases sharply near the curvature area of the desgined channel. ② In the area of the curvature of the designed channel, maneuvering risk increases sharply with the danger of running aground under the environmental condition of current and wind comung from the stem.

• Journal of the Korean Society of Marine Environment & Safety
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• v.2 no.1
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• pp.35-45
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• 1996

The assesment of the safety of ship's transit in a curved narrow channel consists of the maneuvering safety determined by the chance of running aground, the maneuvering difficulty determined by ship's workload, and shiphandler's subjective evaluation. In this study to examine the correlation between shiphandler's subjective evaluation and the maneuvering risk, the real-time and full-mission shiphandling simulator in the Korea Marine Training & Research Institutes(KMTRI) was utilized. On the conning bridge of the shiphandling simulator, 50 experienced masters conducted the modeled vessel of 60,000 deadweight tonnage along the designed channel under 3 different environmental conditions. The findings were as follows : (1) The frequencies of stress levels, work difficulties, vessel controllability and overall workload of shiphandlers are similar irrespective of environmental conditions and they are able to be represented as shiphandler's subjective evaluation. (2) It s possible to assess and analyze theoretically the correlation between the shiphandler's subjective evaluation and maneuvering risk under each environmental condition by quantifying the data obtained from the test. The results are as follows : ① As the degree of maneuvering risk increases, the shiphandler's subjective evaluation increases sharply near the curvature area of the designed channel. ② In the area of the curvature of the designed channel, maneuvering risk sincreases sharply with the danger of running aground under the environmental condition of current and wind coming from the stern.

• Journal of Ship and Ocean Technology
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• v.1 no.1
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• pp.35-47
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• 1997

The consequences associated with ships running aground depend very much on the soil characteristics of the sea bed and the geometrical shape of the ship bow. The penetration into the sea bed depends on these factors and the penetration is an important factor for the ship motion because it influences the ship heave and pitch motions as well as the friction between the ship and the soil. In this paper a rational calculation model is presented for the sea bed soil reaction forces on the ship bottom. The model is based on the assumption that the penetration of the ship bow generates a flow of pore water through the grain skeleton of the soil. The flow is governed by Darcy\`s law and it is driven by the pressure of the pore water at the bow. In addition to this pore water pressure, the bow is subjected to the effective stresses in the grain skeleton at the bow surface. These stresses are determined by the theory of frictional soils in rupture. Frictional stresses on the bow surface are assumed to be related to the normal pressure by a simple Coulomb relation. The total soil reaction as a function of velocity and penetration is found by integration of normal pressure and frictional stresses over the surface of the bow. The analysis procedure is implemented in a computer program for time domain rigid body analysis of ships running aground and it is verified in the paper through a comparison of calculated stopping lengths, effective coefficients of friction, and sea bed penetrations with corresponding experimental results obtained by model tests as well as large, scale tests.

• Journal of Navigation and Port Research
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• v.34 no.9
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• pp.693-698
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• 2010

In port and its approach channel, traffic accidents such as collision, aground, minor collision have reached about 77% of total marine casualty in the area. In this paper, an attempt to enhance the safe navigation was proposed by offering marine traffic supporting system which helps VTS operator assist vessel effectively with the quantitative assessment on difficulty of each vessel. The system collects navigation data from onboard AIS, assesses the data in assessment mode to analyze the navigation difficulties of each vessel and displays the degree of danger of each vessel on the ECDIS in real-time to decide the intervention time or order of priority for VTS operator. The effectiveness of the system was verified by the VTS operators in Korea.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.3
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• pp.28-38
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• 1998

In our paper is reported a new 3D(dimensional) trajectory split approach with greatly improved efficiency for the Monte Carlo simulation of the 3D profiles of implanted ionand point defect concentrations in single-crystal silicon. This approach has been successfully implemented in our TRICSI Monte Carlo code. Combined with the previously developed model for damage accumalation in our TRICSI code, this model allows phasically based dynamic simulation of 3D profiles over an subsequent process simulation such as diffusion modeling and simulation. A typical time saving of over 10 timeshas been achieved for 3D simulation. Our method ensures much better region aground the implanted area. For 1-D simulation, the optimized condition for trajectory split has set to 3,000 pseudoparticles with 2 split branches.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.4
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• pp.901-905
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• 2000

An elliptical ogive head for a generic missile is proposed to reduce its detectable probability from aground defense radar. Numerical RCS results of a generic missile with an elliptical ogive head are evaluated using the GTD/UTD (Geometrical Theory of Diffraction/uniform GTD). The results are compared with those of a cylindrical ogive head. In the sense of aerodynamics, the performance evaluation of an elliptical ogive head for a generic missile should be followed.

• Journal of the Korean Institute of Navigation
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• v.18 no.4
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• pp.1-9
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• 1994

Assessment of the safety of ship's transit in the narrow channel consist of the maneuvering safety determined by the chance of running aground, the maneuvering difficulty determined by ship's workload and master's subjective evaluation. To examine the relation between master's subjective evaluation and maneuvering safety, this utilizes a real-time and full-mission shiphandling simulator in the Korea Marine Training & Research Institutes(KMTRI). The vessel chosen was 60,000-ton, Panamax-type ship. The findings regarding master's subjective evaluation were as follows: -Relation between master's subjective evaluation and common logarithms of stranding probability is linear. -Stranding probability with more than 0.001 is master's subjective evaluation with more than 5.

• Journal of the Korean Society of Marine Environment & Safety
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• v.14 no.1
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• pp.77-82
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• 2008

Recently, fatigue related to marine accidents was recognized to be very important contribution factor when marine accidents such as collision, aground, fire, etc. were investigated Many studies concerned about fatigue factors related to human error can be found. In this study, the analysis and examination of USCG Fatigue Investigation Program were carried out in order to investigate marine accidents happened in Korean waters. The Fatigue Investigation Program was established on the MAIFA(Marine Accident Investigators Forum in Asia) web site. Finally, the application plan of the program was discussed.

• Journal of the Korean Institute of Navigation
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• v.20 no.3
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• pp.13-30
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• 1996

It is general that large ships entering or leaving a port located in the East coast of Korean peninsular are often exposed athwart to swell while maneuvering in the vicinity of breakwater at harbor enterance or to prevailing wind inside the port in winter. Particulary, Many VLCCs laden with ore coal are calling at Pohang Port, on account of which it is likely that one of those VLCCs block the port if they were to run aground in fairway due to adverse circumstance of swell, prevailing winds or improper shiphandling. This accident may result in delay of delivery of raw material for Pohang Steel Mill which will bring about shortcomings of steel products for nationwide relevant industries causing national economic shock. Therefore, This study basically aims at establishment of certain criteria for safe unberthing of VLCC in this port to prevent such unexpected disaster because any VLLC is highly affected by external forces when in ballast condition. Computer simulations are unavoidable to fulfull this study successfuly and many simulations have been carried out repeatedly to find a model of safe unberthing under various unfavourable wind conditions. The "PC-based ship maneuvering simulator for training purpose" was used to perform numerous simulations at the least economic burden and to verify its availability that it can be used not only for training but also some other purposes. purposes.