• Special Issue of the Society of Naval Architects of Korea
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• 2007.09a
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• pp.94-98
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• 2007

The latest development of the submarine oil field and the deep-sea explorer, FPSO is commonly proposed and used for offshore oil production. And because the fundamental requirement of FPSOs to remain moored at their position, they are unable to avoid severe weather and environment. FPSO normally operates head to the weather, and sensitive equipment located the exposed area will be influenced by green water damages, the damages may occur to both onboard equipment and topside structures with resulting risk to personnel. In this paper, the main focus considers the physical structures of green water protector in order to preserve topside structures, equipment and personnel from green water.

• Fisheries and Aquatic Sciences
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• v.1 no.2
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• pp.168-179
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• 1998

Circulation in the Jinhae Bay in the southern sea of Korea is examined using the Princeton Ocean Model (POM) with a free surface in a sigma coordinate, governed by primitive equations. The model well corresponds to the time series of the observed velocities at several layers obtained from a long-term mooring observation. In the residual velocity field of the model, persistent downward flow fields are formed along the central deep regions in the bay, and they are caused by bottom topographic effect. In addition, a comparison between a depth-averaged (2D) model and the POM is given, and a dependance of the results on bottom drag coefficient is also examined.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 2003.08a
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• pp.35-43
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• 2003

Methods for measuring wave height and direction varies throughout the world, depending on wave climate and local traditions. In Japan, bottom mounted systems have long been the standard fur coastal areas with water depth less than 50m, and extensive studies in the 1980s and 1990s refined the systems to a level where the full wave directional spectrum could be measured. (omitted)

• International Journal of Ocean Engineering and Technology Speciallssue:Selected Papers
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• v.5 no.1
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• pp.29-39
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• 2002

A general investifation into the physical mechanism that is respinsible for drag above the sea surface has been undertaken. On the basis of a ID model of the Wave Boundary Layer(WBL), under a 2D wave field, a parameterization technique for estimation of the drag and mean characteristics of WBL is described. Special attention is paid to estimation of the simplifying assumption of the theory.

• Journal of the Korean Institute of Navigation
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• v.22 no.4
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• pp.31-36
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• 1998

The whistle is a very important information source for the safety navigation under foggy weather. But navigator has no concern about this, because it must be achived by human hearing sense and considered as a vague signal. If the range and relative bearing of signal source can be detected automatically, it would be very useful system for preventing marine casualties making a lot of economic loss and environment pollution. Before the algorithm of 2-dimensional sound source tracking system was reported. This paper describes the method that can obtain the time lag between three signals and the theory of cross-correlation analysis and subtraction method for cauculating the time lag by using the digital signal data sequences. And a series of experiments were carried out for various position of sound source in the range from 200cm to 530cm. As a result, we have recognized that sound source tracking system is possible to the sea field with improvement of position error.

• Journal of Korean Port Research
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• v.13 no.2
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• pp.427-436
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• 1999

Simulation model for diffusion of oil spill is developed. The model can perform real time simulation in the case of oil spill accident in the ocean. The model consists of three dimensional ocean circulation model and model for diffusion of oil spill. Real time flow fields which are used in the calculation of advection of oil spill are obtained in the three dimensional ocean circulation model. The model for diffusion of oil spill includes the evaporation dissolution emulsification and downward diffusion. For the verification of the model it is applied to the oil spill from the accident of Sea Prince. The results shows good agreement.

• The Journal of Fisheries Business Administration
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• v.29 no.1
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• pp.89-120
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• 1998

This paper aims to investigate the actual conditions of the fishing villages and the attitudes of fishery workers. In this study, field research, interview method, and survey research method are utilized. The regions of this research are 4 fishing villages of the Yellow Sea coast and the survey data are collected from 119 fishermen. The results show that the fishery industry has come to a crisis due to the staggering fish catches and fishery income, increasing expenditures am debt, continuous decrease in numbers of fishery workers, etc. In addition, the work morale of the fishermen appears to be very low. They take a dim view of fishery industry and their household financial status. They perceive that their qualities of life are very low as well. The implications of these findings far comprehensive development of fishing villages are then discussed.

• Journal of the Korean Society of Marine Environment & Safety
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• v.3 no.2
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• pp.1-12
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• 1997

One of the main uses for ship simulators is in the field of port design, and an increasing number of simulators, of varying degrees of fidelity, are being used for this purpose. An essential feature of all such simulators is their visual scene, which must be of sufficent fidelity to convey the key visual cues adequately. This paper examines the ability of a number of experienced mariners to perceive speeds and distances correctly using Computer Generated Imagery visual scenes of different fidelity, compared with their performance at sea. From the results, it was found that the microcomputer based simulator might be considered, as far as its visual scene representation is concerned, to be as valid as the full mission ship simulator for the port design task.

• Journal of the Korean Geophysical Society
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• v.6 no.2
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• pp.79-87
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• 2003

An in-situ four-electrode contact resistivity probe system was designed, and field-tested in submarine sediments. Seismic survey was also performed to support and compare the results of electric survey. The probe was designed to be driven to selected depths below the seafloor using a Vibracore system. The four insulated electrodes were, spaced equidistant across the wedge, were extended beyond the probe tip to minimize effects of sediment disturbance by the wedge insertion. In-situ measurements of resistivity were recorded on board by precision electronic equipment consisting of signal generators and processors, and by temperature- monitoring systems. Overall limits of uncertainty at respective depths below the seafloor are up to ±10% of the measured values. Best estimates of conductivity are considered to be ±3 percent of the reported values. Resistivity measurements were made at six sites in carbonate sediments to a maximum depth of penetration of about 5 m. Average values of conductivity range between 0.88 and 1.21 mho/m. The results show the seabed is composed of alternating layers of relatively high-conductivity material (0.8 to 1.4 mho/m) in thicknesses of more or less one meter and layers about 30 cm thick having relatively low conductivities (0.4 to 0.8 mho/m).

• Water for future
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• v.24 no.3
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• pp.83-94
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• 1991

In this paper a discrete extended Kalman filter for the tidal prediction has been developed. The filter is based on a set of difference equations derived from the one dimensional shallow water equations using the finite difference scheme proposed by Lax-Wendroff. The filter gives estimates of the water level and water velocity, together with the parameters in the model which essentially have a random character, e.g. bottom friction and wind stress. The estimates are propagated and updated by the filter when the physical circumstances change. The Kalman-filter is applied to field data gathered in the coastal area alon the West Sea and it is shown that the filter gives satisfactory results in forecasting the waterlevels during storm surge periods.