• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1996.04a
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• pp.77-92
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• 1996

When an automatic course-keeping is concerned as is quite popular in modern navigation the closed-loop steering system consists of autopilot device power unit (or telemotor unit) steering gear magnetic or gyro compass and ship dynamics. The consideration of irregular disturbances to ship dyanmics and a few non-linear mechanisms involved in the system inevitably or artificially are known to be very important in properly evaluating or analyzing the automatic steering system. In the present study the mathematical model of each element of an automatic steering system is derived which takes account of a fex non-linear mechanisms. PD(Proportional-Derivative) controller and low-pass filter with a weather adjustment are adopted to modelling the characteristics of an autopilot. The calculation method of imposing irregular disturbances to ship dynamics is proposed where irregular disturbances implying irregular wave and the fluctuating component of wind. For he evaluation of automatic steering system of ships in the open seas an important term "performance index" is introduced from the viewpoint of energy saving which derived from the concept of energy loss on ship propulsion. Finally the present methods are applied to two typical types of ship ; an ore carrier and a fishing boat. The various effects of linear and/or non-linear control constants of autopilot on propulsive energy loss are investigated to validate and clarify the present smulation technique.

• Journal of Navigation and Port Research
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• v.39 no.2
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• pp.89-97
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• 2015

The rising spate of piracy in Nigeria's territorial waters has become a burden on the economic development of the country. It has adversely affected the exportation of crude oil, which is the mainstay of the country's economy. Pirates target and hijack vessels carrying oil and gas, thus reducing the revenue accruable to the country from selling these resources. Piracy also affects the fishing industry which is another source of revenue to the country. Nigeria, as an import dependent country, relies on the importation of finished goods, and this is seriously affected by piracy. This study briefly examines the root causes of piracy in Nigeria. Further, the study interrogates the effects of piracy, identifies the challenges in the suppression of the crime and proffers suggestions toward suppressing the crime in the country. Against this backdrop, the study argues, among other things, that an expansive definition of piracy is key in the fight against this maritime crime in Nigeria, because the present legal regime is restrictive and limited in scope, thus, it does not reflect the modern piratical acts. More importantly, Nigeria must criminalise piracy in its domestic law in other to police its territorial waters, capture and prosecute pirates in its local courts.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2006.11a
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• pp.477-480
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• 2006

본 논문에서는 한국 동해 강구항 전면해역에서 계절풍이 탁월한 3월과 태풍 우쿵(WUKONG) 내습시 8월에 수압식 파고계를 이용하여 파랑관측을 실시하였다. 관측파랑자료의 해석을 통해 관측시점에서의 계절풍 및 대풍내습시의 기상현황과 파랑과의 상호관련성, 발생파랑의 통계적 특성을 분석하였다. 그 결과에 따르면 관측기간동안 강구항 전면해역에서는 직립방파제 설계식의 관계식 $H_{max}\;=\;1.8H_S$를 초과하는 고파랑이 태풍 내습시 발생하며, 계절풍이 발달한 시기에는 약 3m 파고의 파랑이 발생하였다.

• Journal of Korean Port Research
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• v.15 no.1
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• pp.57-74
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• 2001

In the past, the predictions of beach processes and harbor sedimentation were mainly relied on the hydraulic model tests and empirical methods. In recent years, however, as computers have come into wide use, more accurate models have gradually been developed and thus replaced those conventional methods. For prediction of topographical change near the coastal area, we need informations of wave and current conditions in the numerical model which should be calculated in advance. Numerical model introduced in this study combines wave refraction-diffraction, breaking, bottom friction, lateral mixing, and critical shear stress and three sub-models for simulating waves, currents, and bottom change were briefly discussed. Simulations of beach processes and harbor sedimentation were also described at the coast neighboring Bangpo Harbor, Anmyundo, Chungnam, where the area has suffered accumulation of drifting sand in a small fishing harbor with a wide tidal range. We also made model test for the new layout of the harbor and planned south breakwater for preventing intrusion of sand. Although the model study gave reasonable description of beach processes and harbor sedimentation mechanism, it is necessary to collect lots of field observation data, including waves, tides and bottom materials, etc. for better prediction.

• Journal of Korea Port Economic Association
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• v.19 no.1
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• pp.89-112
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• 2003

In this article, 1'd like to analyse the principal distinctions between the duty of disclosure and warranty which are based on the same legal principles, utmost good faith(uberrima fides). Although the duty of disclosure and warranty have a same legal principle to protect insurance contract, they have several difference in appliance actually. Through these comparative analysis, 1 want to reveal the character of warranty which is unfamiliar to us under our commercial law. Warranty has some peculiarity, these are (a)A warranty does not have to be material to the risk, (b)A warranty must be exactly complied with, (c)It is impossible to defence for a breach of warranty, the breach of warranty is irremediable, and A casual connection between breach and loss needs not be shone, (d)A breach of a warranty may be waived by insurer. Sometimes in Korea like those stringent principles of warranty make Korean's small fishing or shipping company suffer from difficult because of insistence of discharge from liability by insurer. So I expect that all of them acknowledge the character of warranty and can make them protect their insurance money by themselves.

• Journal of Korean Port Research
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• v.7 no.1
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• pp.89-114
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• 1993

ICLL 66 is the most widely ratified instrument of the IMO and is, along with the International Convention on Safety of life at Sea (SOLAS), the primary document setting forth internationally agreed ship safety standards. ICLL 66 set freeboard requirement based on experience gained from the first Load Line Convention in 1930 and on contemporary developments in ship design. Reexamination of ICLL 66 is indicated by the proliferation of novel ship designs for which it lacks adequate regulations and by significant advancements in analytical seakeeping and deck wetness prediction techniques now available to the designer. In this paper, the Freeboard Advisory Group reviews these issues against the changing climate of the marine industry and maritime administrations, discusses the state of the art in analytical seakeeping programs, and outlines a series of recommendations for the establishment of a new international load line convention for the next century. The steps needs for an international program at IMO are discussed and a new convention is proposed.

• Journal of Navigation and Port Research
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• v.32 no.10
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• pp.765-770
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• 2008

This paper presents the power control for the hybrid electric propulsion system. In this paper, the hybrid propulsion system consists cf the generator and battery as power supply system in ship. The hybrid control system is designed with energy saving algorithm for decreasing the power consumption of power supply system. This paper suggests the method to increase efficiency of hybrid electric propulsion system by developing battery charging system. The performance of power control system is analyzed with the experiment equipment for hybrid propulsion system, and the results showed a good property.

• Proceedings of the Korea Port Economic Association Conference
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• 2003.07a
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• pp.271-294
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• 2003

In this article, 1'd like to analyse the principal distinctions between the duty of disclosure and warranty which are based on the same legal principles, utmost good faith(uberrima fides). Although the duty of disclosure and warranty have a same legal principle to protect insurance contract, they have several difference in appliance actually. Through these comparative analysis, I want to reveal the character of warranty which is unfamiliar to us under our commercial law. Warranty has some peculiarity, these are (a)A warranty does not have to be material to the risk, (b)A warranty must be exactly complied with, (c)It is impossible to defence for a breach of warranty, the breach of warranty is irremediable, and A casual connection between breach and loss needs not be shone, (d)A breach of a warranty may be waived by insurer. Sometimes in Korea like those stringent principles of warranty make Korean's small fishing or shipping company suffer from difficult because of insistence of discharge from liability by insurer. So I expect that all of them acknowledge the character of warranty and can make them protect their insurance money by themselves.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.11a
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• pp.114-115
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• 2023

Research on eco-friendly ships is being actively conducted due to the strengthening of environmental regulations in the shipping sector by the International Maritime Organization (IMO). However, most studies are on large ships, and research on small ships is insufficient. Since most fishermen operate small boats, research on eco-friendly fuel vessels is necessary. This study performed resistance performance analysis, model tests, and POW tests to develop a hybrid electric propulsion ship, and compared and verified the CFD and model test results.

• Journal of Navigation and Port Research
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• v.42 no.4
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• pp.245-252
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• 2018

A method of transmitting an alert signal in case of man-overboard (MOB) systems in a small fishing vessel navigating within coastal area is being operated as VHF-DSC equipment via a distress alert button and V-P ass Equipment via alert button or beacon separation. However, a small fishing vessel with a couple of crews on board is an inappropriate way to alert a man-overboard condition. However, internationally, MOB equipment using VHF-DSC, AIS, and Bluetooth technologies is used to transmit alert signals directly to the mother ship and other radio stations. In order to analyze the performance and technology of the MOB equipment operating in foreign countries, it was confirmed that the alarm signal can be received within a maximum of one nautical mile when the MOB device is on the water surface. An MOB device that meets domestic conditions needs to send an alarm signal to a station within the VHF communication range. However, in order to reduce the false alert signal, it is most appropriate to operate the VHF-DSC radio equipment installed on the ship remotely. Analysis of various technologies connecting the MOB and the VHF-DSC revealed that the Bluetooth system has advantages such as device miniaturization. When an emergency signal is transmitted from the MOB device, it can be received by a dedicated receiver and recognized through an external input terminal of the VHF-DSC equipment generating its own alarm. If the emergency situation cannot be processed at the mother ship, a distress alert is sent to all radio stations via VHF-DSC for response under emergencies faced by small fishing vessels.