• Journal of Ocean Engineering and Technology
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• v.12 no.1
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• pp.135-142
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• 1998

In this study, the frequency transfer function of motions are predicted from the result of a full-scale seakeeping trials. Because the real sea has the characteristics of multi-directional waves,we compare the results in the one directional waves with ones in the directional waves. For calculation of the frequency transfer function in the directional waves, Takezawa's inverse estimation method was introduced and the frequency ranges were divided into three parts in order to consider following seas. The full-scale seakeeping trials was executed in the south sea of Korea using the stern trawler. Those results show that analysis method of the multi-directional waves is more reliable than that of one directional waves, and confirm the possibility of applying this method to the full-scale seakeeping trials.

• IEMEK Journal of Embedded Systems and Applications
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• v.12 no.5
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• pp.287-293
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• 2017

The naval unmanned surface vehicle (USV) conducts the surveillance operations, based on the mission plan set by the user. For setting the mission planning, the user needs to analyze the suitability of the operation for the mission planning. In this paper, we proposed a simulation program that estimates the probability of detecting targets of the mission planning in the analysis. In the simulation analysis, we design the USV's maneuvering characteristics, radar detection operational performance equipped on the USV, and targets infiltrating into surveillance area in the simulation experiment scenario. Based on the simulation results, we evaluated the mission planning suitability and find a mission planning solution recursively.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.671-676
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• 2001

This study are development results of solar hot water system for anchovy proceeding. The heat amounts of boiling vessel are calculated 292.66W at forward and backward direction, and surface direction are calculated 373.14W. The polyenoic rate of anchovy are measured lower as high temperature, but monoenoic and polyacid are higher. Then the others. The maximum radiation of anchovy fishing grounds are shown $350kcal/m^2h$ at pm. 13:00, Chungdo in CHINA. Distributions of Velocity and temperature in boiling vessel are calculation. Solar collector and boiling vessel for anchovy proceeding ship are developed to automatic control system.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.10a
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• pp.36-39
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• 2001

최근 web을 기반으로 한 인터넷과 관련한 기술은 선박설계 과정에서 설계 생산성을 향상시키기 위해 새로운 설계 패러다임에 도입되고 있다. Web을 기반으로 한 선박설계는 분산된 설계환경에서 여러 설계 전문가들이 함께 참여할 수 있게 함으로써 설계정보를 동시에 공유할 수 있도록 하며, 원격지에서도 설계자가 원하는 자료를 검색할 수 있도록 해준다. 현재 소형선박을 설계하는 현장에서는 데이터 베이스가 효율적으로 구축되어 있지 않기 때문에 설계 작업시 수작업이 반복적으로 이루어지고 있다. 이러한 수작업의 반복은 설계 과정에서 에러를 발생시키고 각 설계 단계별로 발생하는 설계 데이터의 손실로 인해 생산성을 저하시키는 요인으로 작용될 수 있다. 본 연구에서는 web 기반을 통한 선박기본계산 서비스를 제공함으로서 설계정보들을 웹 브라우저를 통해서 소형선박을 건조하는 조선소나 설계 용역을 담당하는 설계사무소와 같은 원격지에서도 필요한 데이터를 검색할 수 있도록 제시하였다.

• Journal of Power System Engineering
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• v.7 no.1
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• pp.14-19
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• 2003

A diesel engine has been widely used for ship and industry power because it has many merits of high thermal efficiency, reliability and durability. However its exhaust gas is harmful to human and air environment. Reducing the hurtful exhaust gas emissions, the study of the gas flow in the inlet and exhaust manifold is in progress in the world. In this paper we modeled the gas flow as one dimensional isentropic flow to predict the gas flow in the exhaust manifold. The method of characteristics was used for the model calculation, and the calculated results were compared with the experimental ones.

• Proceedings of the KWS Conference
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• v.43
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• pp.275-277
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• 2004

Fictitious notch radius approach is based on the Neuter's microstructural support hypothesis which assumes that fatigue crack is governed by highly stressed volume of the material right on the weld toe area rather than the surface stress at a pin point of weld toe area. Variety of successes have been achieved in applying this methodology to the fatigue of welded joint, hence, it became one of recommended design procedure in IIW's recommendation as well as many ship classification societies. 1mm fictitious notch radius approach was applied to the various fatigue problems of welded joints in this study covering the effect of weld size, notch stress calculation for 3D geometry and low cycle fatigue problem. It was found that fictitious notch radius approach fumed out to be very effective and accurate in dealing with fatigue strength of welded joint.

• Journal of the Korean Society of Marine Environment & Safety
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• v.6 no.1
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• pp.35-45
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• 2000

The slipway, which is one of stern construction, is necessary for stern trawler to let fishing implements, such as fishing net, otter board and warp, go out effectively. It may be doubtable whether there is any possibility for deckwetness to occur because the slipway is obliquely in contact with sea surface. The author discusses any possibility for deckwetness through slipway of stern trawler in wind and waves. A 350 G/T class, ocean-going stern trawler is adopted for the present study. The stem trawler is particularly assumed to drift with fishing implements hung down the slipway due to internal or external accident during fishing operation in real sea. The author considers two factors as possibility for deckwetness to occur through slipway. One is mooring effect of fishing implements hung down the slipway under wind pressure, and the other is relative ship motion in vertical direction in waves. Through the numerical calculation, the author clarifies that there is thin possibility for deckwetness to occur from above two points of view.

• Journal of the Korea Institute of Military Science and Technology
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• v.4 no.1
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• pp.73-82
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• 2001

In this Paper, slack is computed from a comparision of the cable pay out rate and the ship ground speed in accordance with laying conditions, and the speed controller of the cable engine based on an $H^{\infty}$ servo control is designed for adjusting the cable engine in order to lay a desired amount of slack. The controller is designed to have the robust tracking property of the cable engine under disturbances. The performance of the designed controller is evaluated by computer simulation, and, consequently, a feasibility study for laying the submarine cable stably is done through analyzing simulation results.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2002.05a
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• pp.98-103
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• 2002

In this paper, shock analysis was performed for coarse and fine mesh model using MSC/NASTRAN and ANSYS after substituting the foundation of deck mounted equipment of marine ship for mass-spring system. In order to determine input file in MSC/NASTRAN, dynamic response analysis was also performed using DDAM based on the calculation in the range of low frequency. It was confirmed that the coarse mesh model has the sufficient effective weight in a lower degree mode compared to fine mesh model.

• Journal of Advanced Research in Ocean Engineering
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• v.1 no.1
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• pp.36-43
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• 2015

Since the crack generation and its propagation caused by welding defects is one of the main hull damage patterns, the simulation of crack propagation process has an important significance for ship safety. Based on interface element method, a finite element model to simulate crack propagation is studied in the paper. A Lennard-Jones type potential function is employed to define potential energy of the interface element. Tensile tests of steel flat plates with initial central crack are carried out. Surface energy density and spring critical stress that are suitable for the simulation of crack propagation are determined by comparing numerical calculation and tests results. Based on a large number of simulation results, the curve of simulation correction parameter plotted against the crack length is calculated.