• Journal of Korea Society of Industrial Information Systems
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• v.5 no.3
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• pp.38-43
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• 2000

Active radar reflector may be less familiar, since their uses have been limited to military applications, especially the enhancement of the effective radar cross-sections of missile test range in the drone aircraft and missiles. Perhaps the most widely-Down applications of radar transponders are Identification Friend or Foe(IFF) and its civilian counterpart secondary surveilliance radar for Air Traffic Control(ATC), and most recently, as Search And Rescue Transponder(SART) in the Global Maritime Distress and Safety System(GMDSS). Since it happens frequently accidents on the sea, the problems of the contamination more seriously considered. The conventional navigation buoy and utilities are not sufficient to maintain the safety of the sea and thus new structured concept must be considered. Therefore, this paper propose and implement the active radar reflector with a enhanced function. The results are shown that the performance of the system is significantly improved comparing with the conventional utilities.

• Journal of the Korean Institute of Navigation
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• v.18 no.2
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• pp.129-149
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• 1994

Sea casualties may happen in ship, cargo and the others concerned with sea transportation. : the shipo-wer, marine insurer and salvage company have been endeavored to compensate salvage award with some rule and regulation such as Marine Insurance Act, York Antwerp Rules and Average adjustment rules. Once sea casualties happened, the salvage contract is established between the owners, marine insurance and salvage company, the contract are divided into so many kinds of them. In this paper, we have an analysis on the character of the salvage contract whether the characteristic contents of them are in benefit to any party or not. In this connection with these positive or negative character of the contract, it is worthwhile to compare the actual salvage expenses contract with no cure no pay contract. LOF 1990 has been revised recently, which is based on no cure no pay, expecially, the special compensation, safety net clause of LOF 1990 could be understood in the view of the prevention of sea pollution and the preservation of sea circumstances in the world. Salvage has the complicated and quality, because the adjustment of almost salvage charges have been treated through the other sea casualties which is accompanied by and mixed with. Besides of the importance of salvage contracts, we are in need to understand that what the diversified character of salvage charges are. Furthermore the owners should carefully select the insured conditions on Hull Insurance according to the type of his company, operating ocean route, loading cargo and etc. In this paper, we would try to analyze the character of the salvage award such as General Average, Sue and Labour Charges and Particular charges. We would like to propose that the uniformed system of the salvage award. Compensation should be built up for the effective and efficient salvage operation and for reducing the claims and conflicts from the concerned parties. To this end, we could expect that the uniformed system for salvage award compensation will come to be the benefit of all owners, insurers, salvage company.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.12
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• pp.2636-2641
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• 2010

To support anti-collision between ship to ship and sea-search and sea-rescue work, ship automatic identification system(AIS) that can both send and receive messages between ship and VTS Traffic control have been adopted. And port control system can control traffic vessel service which is co-operated with AIS. For more efficient traffic vessel service, ship recognition and display system is required to cooperated with AIS. In this paper, we propose ship detection system which is co-operated with AIS by using background estimation based on image processing for on the sea or harbor image extracted from camera. We experiment with on the sea or harbor image extracted from real-time input image from camera. By computer simulation and real world test, the proposed system show more effective to ship monitoring.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.2
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• pp.217-225
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• 2024

Even after the introduction of Global Maritime Distress and Safety System (GMDSS), many maritime accidents occur. A method of transmitting a rescue signal when a person falls into the water from a ship is currently being researched and developed in various ways, but no products have been developed that use frequencies allocated for maritime mobile service. Accordingly, in this study, we designed and produced a man-over-board (MOB) device by applying Group B AMRD technologies, which were adopted through the latest revision of the International Telecommunication Union (ITU). In addition, a receiver and user interface were built to verify the performance of the transmitter, and we confirmed that it can be used in conjunction with existing electronic charts. This MOB device satisfies the general and technical requirements of Group B AMRD using AIS technology and uses integrated components for miniaturization for easy portability in a maritime environment. We expect that it will achieve excellent AIS communication and be essential in rapid response and safety in emergency scenarios.

• Journal of Navigation and Port Research
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• v.35 no.8
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• pp.631-636
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• 2011

Stable power supply to a light mounted on a navigational buoy is indispensable factor because unstable power can lead to fatal marine accident. Despite the difference lies between onshore and offshore environment, as well as the power output characteristics, the PV(Photovoltaic) power generation system is designed by the independent onshore power generation system standards. Furthermore, the capacity of PV power generation system does not take into account the structural characteristics of the buoy in the sea. Therefore, the faulty design makes battery over-discharge owing to lack of the power generation and the battery can not supply stable power to the light. This paper introduces a design method for a power system of the PV powered buoy. The data has been acquired for 3 months period, which includes PV-generated electricity, power consumption and battery voltage from experimental buoy. Further, a power management features of the buoy has been analyzed based on the acquired data. From the analysis of the acquired data, it was evident that PV power generation system produces different electric power output depend on its installed environment - land and sea. Based on the analytical result, a design criterion has been proposed for the power system in the navigational buoy.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.31 no.4
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• pp.423-434
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• 1995

It was used boundary element method(BEM) and analysed axisymmetric problem to solve hydraulic cylinder for large vessel acting uniform internal pressure(25N/m super(2)) within elastic limit. This paper was utilized the carbon steel tubes for machine structural purposed model, inner radius was 150mm and outer radius was 250mm, axial length was semi-infinite and the isoparametric element was used. The important results obtained in this study were summarized as follows. Radial, tangential and shearing stress occured the maximum stresses(48, -20 and 34MPa) at the inner radius and the minimum stresses(32, -4 and 18MPa) at the outer radius of the hydraulic cylinder for large vessel. But negative signs have meaning compressive stress and stress diminution ratio was about 0.15MPa/mm. The use of isoparametric element raised accuracy and the increment of input data lessened the error in internal point but computer run-time was increased. The double node was improved the internal solutions to settle discontinuity at corner and the double exponential formula lessened error of stress value at boundary neighborhood. And then coincidence between the analytical and exact results is found to be fairly good, showing that the proposed analytical by BEM is reliable.

• Journal of the Korean Society for Marine Environment & Energy
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• v.8 no.1
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• pp.17-22
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• 2005

The movement of drifting ships on the sea is closely related to marine environmental forces such as waves, currents, winds, etc. To develop a prediction model for trajectories oi drifting ships, an experiment on the movement of drifting ships was carried out in the Southeastern Sea of Korea. Five types of ships including a lire raft and tour ships with G/T 10tons, G/T 2o tons, G/T 50 tons, and G/T 80 tons, were considered in the experiment. The G/T 50 ton class ship was used as a base ship for obtaining the currents, winds and heading angles of ship following the trajectory. The trajectory of each ship was measured by DGPS(Differential Global Positioning System) and collected using APRS(Automatic Position Reporting System) installed on the base ship. The error range in position fix of DGPS are approximately ±1 m. The drift speed of ship in the experiment was between 3％ to 5％ of wind speed and drift direction of ship was deflected by ±90° from wind direction. Also, the heading of drifting ship was normal to wind direction.

• Korea journal of population studies
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• v.19 no.2
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• pp.77-105
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• 1996

The rural problems which we are facing start from the extremely small sized population and the skewed population structure by age and sex. Thus we analyzed the change of the rural population. And we analyzed the recent return migration to the rural areas by comparing the recent in-migrants with out-migrants to rural areas. And by analyzing the rural village survey data which was to show the current characteristics of rural population, we found out the effects of the in-migrants to the rural areas and predicted the futures of rural villages by characteristics. The changes of rural population composition by age was very clear. As the out-migrants towards cities carried on, the population composition of young children aged 0~4 years was low and the aged became thick. The proportion of the population aged 0~4 years was 45.1% of the total population in 1970 and dropped down to 20.4% in 1995, which is predicted to become under 20% from now on. In the same period(1970~1995), the population aged 65 years and over rose from 4.2% to 11.9%. In 1960, before industrialization, the proportion of the population aged 0~4 years in rural areas was higher than that of cities. As the rural young population continuously moves to cities it became lower than that in urban areas from 1975 and the gap grew till 1990. But the proportion of rural population aged 0~4 years in 1995 became 6.2% and the gap reduced. We can say this is the change of the characteristics of in-migrants and out-migrants in the rural areas. Also considering the composition of the population by age group moving from urban to rural area in the late 1980s, 51.8% of the total migrants concentrates upon age group of 20~34 years and these people's educational level was higher than that of out-migrants to urban areas. This fact predicted the changes of the rural population, and the results will turn out as a change in the rural society. However, after comparing the population structure between the pure rural village of Boeun-gun and suburban village of Paju-gun which was agriculture centered village but recently changed rapidly, the recent change of the rural population structure which the in-migrants to rural areas becomes younger is just a phenomenon in the suburban rural areas, not the change of the total rural areas in general. From the characteristics of the population structure of rural village from the field survey on these villages, we can see that in the pure rural villages without any effects from cities the regidents are highly aged, while industrialization and urbanization are making a progress in suburban villages. Therefore, the recent partial change of the rural population structure and the change of characteristics of the in-migrants toward rural areas is effecting and being effected by the population change of areas like suburban rural villages. Although there are return migrants to rural areas to change their jobs into agriculture, this is too minor to appear as a statistic effect.

• Journal of Navigation and Port Research
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• v.28 no.10 s.96
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• pp.899-908
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• 2004

The rise of income and introduction of 5 day a week working system give korean people opportunities to enjoy their leisure time. And many korean people have much interest in oceanic sports such as yachting and also oceanic leisure equipments. With the popularization and development of the equipments, the scope of oceanic activities has been expanding in Korea just as in the advanced oceanic countries. However, The current conditions for the sports in Korea are not advanced and even worse than underdeveloped countries. In order to develop the underdeveloped resources of Korean marina, we need to customize the marina models of advanced nations to serve the specific needs and circumstances of Korea As such we have carried out a comparative analysis of how Austrailia, Newzealand, Singapore, japan and Malaysia operate their marina, reaching the following conclusions. Firstly, in marina operations, in order to protect personal property rights and to preserve the environment, we must operate membership and non-membership, profit and non-profit schemes separately, yet without regulating the dress code entering or leaving the club house. Secondly, in order to accumulate greater value added, new sporting events should be hosted each year. There is also the need for an active use of volunteers, the generation of greater interest in yacht tourism, and the simplification of CIQ procedures for foreign yachts as well as the provision of language services. Thirdly, a permanent yacht school should be established, and classes should be taught by qualified instructors. Beginners, intermediary, and advanced learner classes should be managed separately with special emphasis on the dinghy yacht program for children. Fourthly, arrival and departure at the moorings must be regulated autonomically, and there must be systematic measures for the marina to be able, in part, to compensate for loss and damages to equipment, security and surveillance after usage fees have been paid for. Fifthly, marine safety personnel must be formed in accordance with Korea's current circumstances from civilian organizations in order to be used actively in benchmarking, rescue operations, and oceanic searches at times of disaster at sea.