• Journal of Advanced Marine Engineering and Technology
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• v.13 no.2
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• pp.21-42
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• 1989

Recently, multi-branced driving systems are often used for power station systems or for marine propulsion systems to save the initial cost, the man power and to improve the energy efficiency. As the multi-branched power system has a very complicated vibrating system, its analyzing method is quite different from the ordinary method for the single straight system. In this study, the multi-branched power system is reduced to derive equations of free vibration and some analytical methods are studied to solve these equations and computer programs are developed to calcuate their numerical solutions. And also, equations of forced-damped vibration of the multi-branched power system which involves diesel engines are derived and their solving methods are studied. Some computer programs are developed to get responses of the forced vibration with damping and their results are synthesized to get resultant responses. Finally, exciting forces of diesel engine and damping forces of power driving systems are appreciated to help field engineers by suggesting reasonable method of estimating their values.

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.7
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• pp.842-851
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• 2007

Oscillating foil propulsion, the engineering application of fish-like movement of a hydrofoil, has received in recent decades as a possible competitor for propellers. The oscillating foil produces an effective angle of attack, resulting in a normal force vector with thrust and lift components, and it can be expected to be a new highly effective propulsion system. We have explored propulsion hydrodynamics as a concept in wake flow pattern. The present study has been examined various conditions such as oscillating frequencies and amplitudes in NACA0010 profile. Flow visualizations showed that high thrust was associated with the generation of moderately strong vortices, which subsequently combine with trailing-edge vorticity leading to the formation of a reverse $K\acute{a}rm\acute{a}n$ vortex street. Vortex generation was inherent to jet production and playeda fundamental role in the wake dynamics. And it was shown that the strong thrust coefficient obtained as the Strouhal number was larger.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.47 no.3
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• pp.257-266
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• 2011

Recently, the manufacturers of life-jacket are very interested in the acquisition of USCG(US Coast Guard) approval because the acquisition of USCG approval has an important role in the purchasing decision of the buyer's. Be based on criterion of USCG, we studied how to predict the change of floating position of human model with life-jacket to verify the backside restore. For this, in this study, the human model and the lifejacket was modeled in three dimension, the application program for prediction of floating position was developed, and plugged-in commercial program.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.44 no.1
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• pp.57-67
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• 2008

Recently, Korean shipbuilding industry is keeping up the position of world wide No. 1 in world shipbuilding market share. It is caused by endless efforts to develope new technologies and methods and fast development of IT technologies in Korea, to raise up its productivities and efficiency in shipbuilding industry with many kinds of optimizing methods including genetic algorithm or artificial life algorithm... etc. In this paper, we have suggested the artificial life algorithm with relay search micro genetic algorithm. and we have improved a defect of simple genetic algorithm for its slow convergence speed and added a variety of solution candidates with applying relay search simple genetic algorithm. Finally, we have developed intelligent agent system for ship CAE modeling. We have tried to offer some conveniences a ship engineer for repeated ship CAE modeling by changing ship design repeatedly and to increase its accuracy of a ship model with it.

• Journal of the Society of Naval Architects of Korea
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• v.43 no.4 s.148
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• pp.504-511
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• 2006

In this paper a modern sailing boat for our costal area was developed by using the traditional boat hull form. Main particulars of design ship were determined by using the statistical values. Hull form was varied from the traditional boat hull form which was selected by the previous study and modified to fit Lateen sail. The appendage, rudder and keel were designed for good performance of against wind sailing. The performance of hull form was examined and the results were shown.

• Journal of the Society of Naval Architects of Korea
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• v.42 no.1 s.139
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• pp.50-56
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• 2005

The performance of Traditional Korean Fishing Boat is surveyed based on Report on Investigation of Korean Fishing Boat. The characteristics of Traditional Korean fishing Boat of hull form, rudder, sail are studied from the view point of modern sailing boat design. As a result we find her hull form is an excellent candidate of mother ship for modern boat design and the great sized rudder of Traditional Korean Fishing Boat makes a role of the centerboard of modern sailing host. And also we find the sail of Traditional Korean fishing Boat is more useful for sailing against the wind direction than an ordinary Lug sail.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.13 no.2
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• pp.91-99
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• 2013

An autonomous unmanned underwater vehicle is a type of marine self-propelled robot that executes some specific mission and returns to base on completion of the task. In order to successfully execute the requested operations, the vehicle must be guided by an effective navigation algorithm that enables it to avoid obstacles and follow the best path. Architectures and principles for intelligent dynamic systems are being developed, not only in the underwater arena but also in related areas where the work does not fully justify the name. The problem of increasing the capacity of systems management is highly relevant based on the development of new methods for dynamic analysis, pattern recognition, artificial intelligence, and adaptation. Among the large variety of navigation methods that presently exist, the dynamic window approach is worth noting. It was originally presented by Fox et al. and has been implemented in indoor office robots. In this paper, the dynamic window approach is applied to the marine world by developing and extending it to manipulate vehicles in 3D marine environments. This algorithm is provided to enable efficient avoidance of obstacles and attainment of targets. Experiments conducted using the algorithm in MATLAB indicate that it is an effective obstacle avoidance approach for marine vehicles.

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.5
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• pp.963-973
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• 2001

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.239-245
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• 2006

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.4
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• pp.357-362
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• 2005