• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.11
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• pp.1623-1630
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• 2010

In this study, effective forming methods for reducing the roll-over of a sector tooth, which is a main component of an automotive seat recliner, are proposed. Due to the large amount of roll-over, accurate contact between the inner gear of a sector tooth and the outer gear of a pawl tooth cannot be normally achieved; thus sensitivity and safety for the passengers decrease. To overcome the aforementioned drawback, we investigated the effect of flowcontrol forming methods involving local embossing die, coining punch, and VIC (Variable Inverse Clearance) on the roll-over depth by FE-analysis and an experiment. The results of a fine-blanking experiment for verifying the proposed methods showed that VIC type is decidedly superior from the aspects of reduction of roll-over and tool strength of the sector tooth.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.42 no.3 s.303
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• pp.63-72
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• 2005

In this paper, we propose a deformation technique based on Radial Basis Function (RBF) and a blending technique combining the deformed facial component with the original face for a Virtual Aesthetic Surgery (VAS) system. The deformation technique needs the smoothness and the accuracy to deform the fluid facial components and also needs the locality not to affect or distort the rest of the facial components besides the deformation region. To satisfy these deformation characteristics, The VAS System computes the degree of deformation of lattice cells using RBF based on a Free-Form Deformation (FFD) model. The deformation error is compensated by the coefficients of mapping function, which is recursively solved by the Singular Value Decomposition (SVD) technique using SSE (Sum of Squared Error) between the deformed control points and target control points on base curves. The deformed facial component is blended with an original face using a blending ratio that is computed by the Euclidean distance transform. An experimental result shows that the proposed deformation and blending techniques are very efficient in terms of accuracy and distortion.

• The Journal of the Acoustical Society of Korea
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• v.16 no.2
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• pp.10-15
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• 1997

The hydrophones is mounted in many applications on a vibrating surface and functions as an underwater acoustic signal receiver without sensing the vibrations from the mounting surface. However, their performance is usually degraded by the interference of exterior noises such as acoustic cavitation in water stream, host structural vibration in the hull, and propeller motions. This paper describes the design and evaluation of a self noise suppressing hydrophones which shows very poor sensitivity to the external noises, first, effects of the external noise on the its receiver performance is simulated with finite element method(FEM). Second, the geometrical variations are implemented on the original structure that include additional air pockets and acoustic walls which work as acoustic shied or scatter of the noises. The results show that the effect of the external noise is the most significant when it is applied near to the bottom of the side wall of the hydrophones. The transverse noise induced by the outside water flow is isolated most effectively when a thin compliant (damping) layer combined with two air pockets is inserted to the circumference of the nose. Noise level is reduced about fifty nine percent of that of the original structure.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.8
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• pp.553-561
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• 2017

The main motivation for this study was to establish a CFD-based procedure for the analysis of heating characteristics, particularly in industrial furnaces. As certain open-source software packages have gained popularity in dealing with complex industrial problems, the OpenFOAM framework was selected for further development of advanced physical models to meet industrial requirements. In this study, the newly developed comprehensive model was applied to simulate physical processes in the full-scale horizontal furnace of a continuous galvanizing line (CGL). The numerical results obtained indicate that the current approach predicts heating characteristics reasonably well. It was also found that radiative heat transfer plays a dominant role in heating the moving strip. To improve the predictability of our method, further work is required to model the turbulence-chemistry interaction realistically, as well as to impose a physically correct thermal wall boundary condition.

• Resources Recycling
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• v.5 no.3
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• pp.24-30
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• 1996

The computcr s~mulatiun model in vanaus s~nelllng process for melling waste cashhg sand was developed by using energy and malcrial balance concept. This modcl can prcdict the coal, flux and oxygen conaumptron and thc volume and temperature of off-gas The ~niljor critical varlablcs for smclting process can be crplained by using the analysis of energy and malc~ialb alance. Thc Innst lmportarlt variables lor smelting process were h i ~ hpo st-combust~anr atla, high heat transfer crficiency and refractory pratcclion lechnalogy. For saving encrg), in this smelting proccss, selection of caw marerials i.e coal, flus was important, cspacially ubi~go f low volatile coal was prufitahle.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.3
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• pp.1519-1526
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• 2013

This study reviewed the capturing performance of a canopy hood used in some melting processes of a casting manufacturing factory through a site survey. In addition, this study compared and evaluated the flow field and pressure field for the plans to enhance the hazardous air pollutants collection capacity by using CFD model. The case-2(flange attached + double hood) can be improved in terms of collection performance, but is expected to increase in hood static pressure by about 70% more than the existing structure, so it was shown that its site applicability is not good. It is judged that the shape of case-3(flange attached + double cone attached) is most suitable to improve the suction efficiency. This is because a double cone is installed at the center of the opening to concentrate the flow rate on the edge of the hood and control the hume rising to the center of the hood without a static pressure rise via the slope of the cone.

• The Journal of the Korea Contents Association
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• v.15 no.10
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• pp.504-516
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• 2015

This study addresses one of the curent issues in modern finance, which investigates financial profile on the levels of the chaebol firms' cash hoardings in the domestic capital market. Iit may be imperative to search for robust and consistent financial determinants of cash holdings as well as identifying any changes or trend of the determinants affecting the corporate cash reserves in the post-era of the global financial turmoil, considering that interest parties at the government and corporate levels, still seem to have a controversy or debate on excess cash savings. Two hypotheses were postulated and empirically tested for the chaebol firms in the study, such as any transitional changes of the relevant factors on cash holdings and unique attributes of financial factors discriminating between the different type of domestic stock markets.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.535-538
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• 2009

Auto Pilot is the system which move automatically the vessel through locating operation mode to automatic after entering operating course using a electronic chart or plotter. And water jet is the a propulsion system that make a power to push the vessel through spouting the accelerated water which is absolbed by the hole in the bottom of vessel. The water jet receive the effect of the depth of water lowly, it's acceletion efficiency is higher under high speed and have an advantage on vibrating and floating sound, so it's demand is increasing as new propulsion system. However, the signal systems of auto Pilot and water jet are defferant, we need the system to communicate between each system. We propose the interface system which communicate between Auto pilot and water jet efficiently in this journal.

• Journal of Korea Port Economic Association
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• v.25 no.2
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• pp.259-276
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• 2009

The study herein has focused on offering foundation infrastructure in order for seamen who arrive at Korean ports to use internet service smoothly in waiting time and free time. It also concentrated on how to build communication infrastructure for efficient operations when improving existing ports and developing new ports. For this, it has grasped the tendency of researches concerning the existing port communication and has also investigated the status and problems of communication infrastructure being used currently in ports. So it has suggested several realistic development methods based on mesh network and has reviewed them in terms of the stability, economic feasibility and efficiency. Additionally, this research offers the results of the performance test conducted on major equipment in market by the suggested methods. This research can be a good guideline in building wireless communication systems of ports and is expected to contribute to creating traffic volume by improving the image of ports.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.2
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• pp.152-159
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• 2018

A numerical simulation was conducted to establish the analysis methods of the unsteady conjugated heat transfer with a hot gas valve. Two methods are proposed to reduce the computational cost and analysis time of the unsteady conjugate heat transfer; namely, the multi-section analysis method and the one-way analysis method. The multi-section analysis method exhibits relatively high reliability. In the one-way analysis method, the unsteady conjugate heat transfer from the fluid domain to the solid domain was simulated from the analysis results of the steady-state flowfield. The incipient accuracy of the analysis results obtained by the one-way analysis method was slightly lower than that of the results obtained by the multi-section analysis method. However, the discrepancy became smaller with time, as the analysis progressed.