• KIEAE Journal
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• v.13 no.4
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• pp.63-68
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• 2013

On the electricity consumption in Korea, the lighting sector takes about 17% of annual total electricity consumptions. In the midst of higher interests on energy conservation measures, design and choice of energy-saving lighting fixtures have been more important. With growth of technology-intensive industries like advanced material, semiconductor, and biotechnology from the 1980s, needs for clean room and thus illumination at clean rooms have been increased. In this paper, development, specification, and features of a Teardrop LED(hereinafter TD LED) lighting fixture as replacement of Teardrop florescent lighting one that has been popularly installed at clean rooms were presented. Also we performed the economic analysis of return on investment(ROI) about energy savings by the installation of the TD LED lighting fixture at a new-built clean room. The economic analysis showed that the new-developed TD LED lighting fixture would be able to withdraw the initial installation cost within 4 years. Lastly, improvement directions and development plans of the next TD LED lighting fixture for wider applications at clean rooms were described.

• Current Industrial and Technological Trends in Aerospace
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• v.8 no.1
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• pp.55-61
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• 2010

Thermal vacuum test should be carried out to verify the performance of the S/C on the ground under the simulated space environment. KARI already completed the construction of a Large Thermal Vacuum Chamber(LTVC) with 8 m of diameter and 10 m of length dimension. LTVC is for the purpose of performing the orbital environment test for large Space Craft(S/C). Inside LTVC, S/C is much smaller than LTVC. For the function test of S/C during the thermal vacuum test, the S/C has to be connected to Electrical Ground Support Equipment(EGSE) which includes several cable and RF wave guide inside LTVC. Also, MLI should be installed on S/C before the test. But it is very difficult to access the S/C inside big LTVC. To solve the accessibility to the S/C inside LTVC, KARI designed an access fixture. This fixture provides easy access to the any S/C thus can help safe installation and saving time for the related work inside LTVC. This paper describes whole process for the design of the access fixture.

• Journal of Biomedical Engineering Research
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• v.31 no.1
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• pp.56-66
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• 2010

The various total replacement artificial discs have developed because spinal fusion has shown a lesser mobility of an operated segment and an accelerated degeneration at adjacent discs. But almost artificial discs have not yet been reached on the substitute surgery of fusion because many problems such as those clinical success rates were not more than them of fusion have not solved. In this paper, vertically inserted assemble-screw fixture in vertebrae was proposed to improve the fixed capability of artificial disc. And also, to evaluate the design suitability of newly designed screw-type, including fixtures of commercial discs such as wedge and plate type, the 1/4 finite element model with a vertebra and various implanted fixtures were generated, and next, 3 bending motions such as flexion, bending and twisting under the moment of 10Nm and compression under the force of 1000N were considered, respectively and finally, FE analyses were performed. Results of three fixture types were compared, such as Range of Motion and maximal stress, and so on. For ROM, the screw type was average 58% less than the wedge type and was average 42% less than the plate type under all loading conditions. For average stress ratio at closer nodes between vertebra and each fixture, the wedge type was the lowest as minimum 0.02 in twisting, screw types were the highest as maximum 0.28 in compression. As the results of using cement material, it was predicted that the instability problem of the wedge type was better solved. The screw type which could be increased by implanting depth according to the number of assembling mid screws, showed that the decreased tendency of ROMs and maximal cancellous bone stresses. In further study, controlling the number of assembling screws that was suitable for a patient's bone quality, development of surgical tools and keeping on design supplementations, which will be able to develop the competitive artificial disc.

• IE interfaces
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• v.4 no.2
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• pp.1-12
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• 1991

This paper deals with the development of a computer aided fixture planning system that automatically selects set-ups, set-up sequence and fixture design for prismatic parts. This study presents the hierarchical data structure for feature-based part model and the preprocessing procedure for the proposed system. The preprocessing procedure generates tools such as DDR(Degree of Dimensional Relationship), AMV(Admissible Misalignment Value) and the datum reference frame of each feature according to the proposed decision table. The proposed system is called AFIX(Automated FIXture planning system) which is implemented by using C language on the workstation. A case study for a cavity plate is presented to show the performance of the AFM.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.828-829
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• 2008

This paper proposes a new pole shaped magnetizing fixture with a non uniform air gap for sinusoidal magnetizing a ring type permanent magnet (PM) to reduce the cogging torque. To obtain more sinusoidal distributed magnetic flux density, the magnetizing fixture's pole shape is optimized by using the sequential response surface method (RSM). And the effects of each design parameter were investigated using the magnetic analysis combined a time stepping finite element method (FEM) with Preisach model. It has been shown, through numerical analysis the optimized modelgives near sinusoidal distributed air gap flux density and drastically reduced cogging torque.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.2
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• pp.206-215
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• 1994

A method for simulating general characteristics and temperature characteristics of discharging SCR of the capacitor discharge impulse magnetizer-magnetizing fixture system using SPICE is presented. This method has been developed which can aid the design, understanding and inexpensive, time-saving of magnetizing circuit. As the detailed characteristic of magnetizing circuit can be obtained, the efficient design of the magntizing circuit which produce desired magnet will be possible using our SPICE modeling. Especially, computation of the temperature rise of discharging SCR is very important since it gives some indication of thermal characteristic of discharging circuit. It is implemented on a 486 personal computer, and the modeling results are checked against experimental measures. The experimental results have been achived using 305[V] and 607[V] charging voltage, low-energy capacitor discharge impulse magnetizer-magnetizing fixture of air cleaner DC motor.

• Proceedings of the KIEE Conference
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• 1997.07a
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• pp.319-321
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• 1997

This paper deals with multipolar magnetizing process which can exert a considerable influence on the final performance of permanent magnet machine. In combination with impulse discharge magnetizer, the analysis and design of magnetizing fixture using finite element method is required to obtain the accurate characteristics of permanent magnet for small-size step motor. Simulated result of flux density shows good agreement with measured one.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.9
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• pp.769-775
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• 2016

Currently, dental implants are widely used as artificial teeth due to their good chewing performance and long life cycle. Generally, a dental implant consists of an abutment as the upper part and a fixture as the lower part. When chewing forces are repeatedly applied to a dental implant, a gap is often generated at the interfacial surface between the abutment and the fixture, and it results in some deterioration such as loosening of the fastening screw, dental retraction and fixture fracture. To enhance the sealing performance for coping with such problems, this study proposes a new sealing-type abutment having a number of grooves along the conical surface circumference, and it carries out finite element analysis in consideration of the external chewing force and pretension between the abutment and the fixture. The result shows that the proposed sealing-type abutment shows an enhanced sealing performance in terms of the contact pressure in comparison with a conventional abutment.

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.5
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• pp.584-593
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• 2006

Statement of problem : Dental implant which has been developed gradually through many experiments and clinical applications is presently used to various dental prosthetic treatments. To conduct a successful function of implant prosthesis in oral cavity for a long time, it is important that not only structure materials must have the biocompatibility, but also the prosthesis must be designed for the stress, which is occurred in occlusion, to scatter adequately of load support. Therefore, it is essential to give the consideration about the stress analysis of supporting tissues for higher successful rates. Purpose : Recently, many implant manufacturing company produce various taper design of root form implant, the fixture is often selected. However, the stress analysis of taper form fixture still requires more studies. Material and method : This study we make the element models that five implant fixture; Branemark system(Nobel Biocare, Gothenberg, Sweden), Camlog system(Altatec, Germany), Astra system(Astra Tech, Sweden), 3i system(Implant Innovations Inc, USA), Avana system(Osstem, Korea) were placed in the area of mandibular first premolar and prosthesis fabricated, which we compared with stress distribution using the three-dimension finite element analysis under two loading condition. Results : This study compares the aspect of stress distribution of each system with the standard of Von mises stress, among many resulted from finite element analysis so that this research gets the following results. 1. In all implant system, oblique loading of maximum Von mises stress of implant, alveolar bone and crown is higher than vertical loading of those. 2. Regardless of loading conditions and type of system, cortical bone which contacts with implant fixture top area has high stress, and cancellous bone has a little stress. under the vertical loading, maximum Von mises stress is more higher in order of Branemark, Camlog, Astra, 3i, Avana. under the horizontal loading, maximum Von mises is more higher in order of Camlog, Branemark, Astra, 3i, Avana.

• Composites Research
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• v.27 no.4
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• pp.158-167
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• 2014

Final goal of this research is to establish the database for correlation factors which connects the test and analysis results of shear buckling allowables for composite plate. To accomplish the goal, extensive test and analysis works are required. In this paper, as the first step, a frame-type fixture for shear buckling test was designed and validated through the test and analysis. Final configuration of the fixture were determined via parametric study on the effect of specimen size, cross-sectional dimensions, and number of fastening bolts on the shear buckling load. Results of the study showed the designed frame-type fixture successfully induces the shear buckling of composite plate. However, there were deviations between the test results and analysis results for ideal case under pure shear load, which were mainly caused by the difference in plate sizes for both cases. The difference were larger in the plates with larger hole and simply supported boundary condition. It is concluded from the results that while the designed fixture can be used for the clamped plates with acceptable accuracy, it shows larger difference in the simply supported plates.