• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.456-461
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• 2004

In this study, the characteristics of the cavitation behavior around hydrofoil are investigated with the commercial CFD code CFX-5. Calculations are performed for NACA 64108 hydrofoil by solving the time-averaged turbulent Navier-Stokes equations and discretized by finite volume method. We classify the different cavitating regimes in which appear at the hydrofoil according to the values of cavitation number, surface roughness and angle of attack. Special attention is paid to the following topics: cavity length, void fraction and lift breakdown.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.9
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• pp.1091-1101
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• 1988

In this paper, a method to segment each character and extract figure from Korean documents is proposed. At first, each character string is extracted by means of iterative horizontal propagation, shrink algorithm and run-length algorithm. Individual character region is extracted by iterative horizontal and vertical manipulation. Next, characters of right pitch are searched. Each character is segmented by the position information. Overlapped character is segmented on the ground of the width of already extracted character. The rest are extracted as special characters of half pitch. Using 9 data input in the form of 840 X 600 from Korean monthly magazine, experiment was simulated. Extraction rate of character is 100%, and that of individual character is 98%. Judging from these results, efficiency on extracting character region and segmenting individual character is proved.

• Special Issue of the Society of Naval Architects of Korea
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• 2005.06a
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• pp.198-205
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• 2005

Reduction of labor hour for cleaning up of the used abrasives after blasting. is attempted by improving the efficiency of abrasive recovery process in the protective coating of ship's block, For this purpose, the theoretical background for pneumatic transport technology in the abrasive recovery system as well as experimental evaluation on the effect of design parameters such as flow pattern, saltation velocity and pressure drop on the efficiency of the abrasive recovery system are employed . By optimizing the operating parameters such as the length and diameter of the suction hose, specification of recovery device and recovery mouth, a new method which can dramatically increase the efficiency of abrasive recovery system, is proposed.

• Special Issue of the Society of Naval Architects of Korea
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• 2007.09a
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• pp.135-141
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• 2007

CSR(Common Structure Rules) enter into force on $1^{st}$ April 2006. Generally for double hull tankers of less than 150m in length, the Rules of the individual Classification Society are to be applied. Where high tensile stresses act through an intermediate plate, increased fillet welds or penetration welds are to be used longitudinal/transverse bulkhead primary support member end connections to the double bottom. If workers have begun to make used of established procedures between corrugated BHD and lower stool joint, first to welding on groove of face and then it has to gouging to blow on groove of root. So amount of man-hour increased, productivity secreased.

• Special Issue of the Society of Naval Architects of Korea
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• 2007.09a
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• pp.32-42
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• 2007

Container vessels are required to have a large KMT to load many containers which requires a wide transom stern form. The wide transom stern generates large stern waves particularly at the scantling draft. This means that reducing the stern wave leads to resistance reduction. Numerical analyses and Model tests for duck-tail of the stern part have been performed to reduce the resistance of the container vessel having the wide transom on the scantling draft and optimize the form of duck-tail with the change of the design parameter i.e. length and edge height. The optimized duck-tail increases the speed by 0.8 % at scantling draft.

• Journal of Welding and Joining
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• v.16 no.2
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• pp.57-63
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• 1998

This study deals with the friction weldability of machine structural carbon steel (SM45C) to Al-Mg-Si aluminium alloy (A6063). The bonding strength of friction welded joints, from all mechanical test, exceeded that of A6063 base metal, under the condition of friction time 1.5 sec, upset pressure 80MPa. The friction welded joints under these conditions exhibited tensile strength of 262MPa, bending angle of 90$^{\circ}$ without crack at weld interface and shear strength of 113MPa. Consequently, the friction weldability of SM4C to A6063 was very excellent, and that was possible without special preparation of weld surfaces.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.10a
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• pp.103-110
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• 1999

Dynamic responses of steel composite bridges for the Korean high-speed railway are analyzed by a modal analysis. The bridge is modeled as a simply supported beam structure and a vehicle of TGV-K is modeled using a moving load assumption. When the train is moving on a bridge, its deck shows resonance phenomenon at a critical velocity. However, it is observed that the dynamic response is greatly reduced at a special range of the span length. The results show that the reduction effect should be considered ill designing the railway bridges. A parametric study of tile dynamic response is performed for different span lengths, and specific train speeds train should be considered in designing the high speed railway bridge are suggested.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.10a
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• pp.135-142
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• 1999

Plate girder bridges for tile Korean high-speed railway are optimally designed. Static and dynamic constraints are all considered. The design variables are the thicknesses and the lengths of the plates that are used to form I-shaped main girders with variable cross-sections. And the objective function is tile steel weight of a main girder. A C++ based design program is developed; this program interfaces with a FORTRAN based optimization program ADS. From the results of optimal design for various span lengths, it is observed that the deck vertical acceleration is one of the most important constraints in a special range of tile span length. Front a parametric study, sensitivity of the optimal design to static as well as dynamic constraints are presented.

• Nuclear Engineering and Technology
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• v.6 no.1
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• pp.27-35
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• 1974

A neutron sensitive ionization chamber has been successfully developed by an improved technique for reactor instrumentation. This instrument is 50mm in diameter and 87cm in length, and can yield a current of 14$\mu$A when in a neutron flux of around 10$^{9}$ nv. The normally required voltage is +350v. The instrument may be removed from operating flux and disassembled immediately without special precautions from radiation.

• Korean Journal of Veterinary Research
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• v.41 no.2
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• pp.261-267
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• 2001

This research was conducted to investigate the effects of race conditions on racing injury in Thoroughbred(TB) horses. A total 335 horses were investigated the relationship between race conditions and racing injuries. The main environmental factors of racing injuries were spring season, rainy weather and sloppy racetrack. In the race types, high incidence of racing injury was found in special weigh, stakes, middle class and long length race. This results suggest that the racing injury can be effected to both individual body condition and various racetrack conditions.