• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.10a
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• pp.49-53
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• 2004

Thin spot welding is frequently used for industrial purpose, such as automobile and aerospace industries and household appliances due to its high performance. In these days, the systemization of welding process made it possible to produce more precise or smaller electric parts. And when it comes to welding of steel sheets, the size of nugget must be getting smaller. Therefore, welding conditions are limited to avoid defects, such as deformation, damage and weakening of joining area. In this research, thin spot welding establishes the welding conditions, and then the measurement of the nugget size by the nondestructive inspection has been conducted. As a result, the right estimation of the nugget size, the detection of corona bond near joining area, the selection of the optimum ultrasonic mode, and setup for ultrasonic inspection are studied. From the trustworthy solutions of the nugget size estimated by results of measurement, the optimum inspection conditions depending upon the width of welding parts are determined as well.

• Journal of Power System Engineering
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• v.5 no.1
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• pp.80-88
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• 2001

The spot welding method has been used in the joining of structures, automotive body, railway carriage, aircraft, household electric appliances, precision parts etc., because of brief working, easy automation, available mass production, and convenience. In this paper, the effects of welding conditions on the fatigue life and the prediction of fatigue life based on fracture mechanics theory of spot welded joint were investigated. Fatigue tests were conducted with the tensile-shear specimens welded in the various current using cold rolled steel sheets. Fatigue life of spot welded joint was predicted and compared with experimental results. Using FEM(finite element method), we analysed the distribution of stress and the condition of deformation on the environments of nugget.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.181-182
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• 2007

Wireless home theater and speaker system was designed. That has 20W output per channel, 0.1% THD (Total Harmonic Distortion) and automatic algorithm avoiding noise. The 3D stereophonic sound was realized through the wireless 5.1channel speaker system designed. That could be secured 0.4% improvement effect of THD compared with wire speaker systems. Specially in transfer sound with wireless, Frequency Hopping Spread Spectrum was superior than Direct Sequence Spread Spectrum in household electric appliances and wireless internet environment that radiated noise similar with ISM Band using 2.4GHz.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1466-1468
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• 2003

PVC insulated flexible cords are widely used as power cord sets in household electric appliances for low voltage. In this paper, we studied the thermal characteristics of power cord sets according to poor contacts between a receptacle and plug pins. In the results of experiments, poor contacts generated heat and ignited the combustibles. And the heat was transmitted to the plug body. While poor contacts were continuing, the electrical waveforms changed. Electrical accidents could be prevented by analyzing these waveforms.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.25 no.5
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• pp.362-367
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• 2016

Recently, wireless charging systems have expanded their applications from household electrical appliances to outdoor activity devices. In wireless charging systems, solar cells have versatile advantages, such as abundant raw materials within the earth, reasonable prices of products, and highest power conversion efficiency. In this study, the photovoltaic effect between a silicon solar cell and a photon of infrared wavelength was simulated using a Shockley diode equation. A solar cell power charging system was then set up to: 1) clarify mechanisms of the charging interaction based on the photovoltaic effect with a laser source, and 2) verify interdependency of the parameters: laser settings and geometrical position between a solar cell and the laser. As was observed, the solar cell generates more power when the photon was irradiated uniformly, intensively, and vertically on the surface of the solar cell.

• Journal of Korea Multimedia Society
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• v.6 no.3
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• pp.488-495
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• 2003

With the development of networks, multimedia communication has expanded its application field. From the remote control for household electric appliances to medicine, games, video conferencing and multimedia chatting, multimedia communication is being used in all parts of our lives. This multimedia communication requires the transmission of a lot of data at high speed. But if the transmission rate of the communication network exceeds the processing speed of being used in the high speed network environment, a bottleneck occurs in each node and deteriorates the performance of the network. This is the main reason for the slow speed of data transmission and packet loss. In this paper, considering the client's processing performance, reception performance was predicted and the way of flow control was shown. The computing performance of relevant Processor and its performance was estimated through the actual implementation.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.35T no.1
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• pp.40-47
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• 1998

The optical heads as the key parts of digital audio/video players are applied extensively from general household electric appliances to computer memory or game apparatuses, and the demand of them tends to be increased according to the extension of optical medium market. In this paper, the 2-axis actuator, the key component for focus servo and tracking servo of the optical head is designed as a type of the cantilever suspended by 4 wires. The design propriety is verified through its simulation and the characteristic analysis of its mock-ups. The other factors which influence the performance of 2-axis actuators besides the design factors of them, are also verified through the mock-up analysis.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1534-1536
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• 2005

A DC-DC converter is being widely used for various household appliances and for industry applications. The DC-DC converter is powered from single battery, and the voltage is varied according to the purpose. In the vehicle, various accessories whose electric power is different are being used. Thus, plural number of DC-DC converter should be provided, so these situations bring complicated circuits, and accordingly, higher cost. Under such backgrounds, in this paper, we propose a novel buck-boost chopper circuit with simply configuration which can supply to two or more different output loads. The propose chewer circuit can control output voltages by controlling duty ratio by using typically two switching devices, which is composed by single boost-switch and single buck-switch. The output voltage can be controlled widely. A few modified circuits developed from the fundamental circuit are represented including the general multi-load circuit. And all this merits and appropriateness was proved by computer simulation and experience.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.11
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• pp.140-147
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• 1995

This paper deals with conversion from the STL file to the Slice to the Slice cross-sectional information for Stereolithography. The STL file is widely used for Stereolithography, but it is very difficult to convert STL file into Slice file directly. Because it consists of an ordered list of triangular net without any topological information other than the orientation of each facet. So, The system is accomplished by data flow through several intermediate stages such as Reference. SL1. .SL2L. .SL3. and .SLC file. The data processing is performed in 5 steps: 1) Create a Reference file including common information. 2) Modify STL file within the effective range of SL machine. 3) Calculate a point of intersection between plane equation and line equation. 4) Sort z values in ascending order using quick sort algorithm. 5) Search the adjacent points and formulate a closed loop usingsingly linked linear list. The system is developed by using Borland C++ 3.1 compiler in the environment of Pentium PC, and verified to be satisfactory by making some prototypes of electric household appliances.

• Hwankyungkyoyuk
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• v.9 no.1
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• pp.58-71
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• 1996

The purpose of this study was to investigate the rural housewives' recognition and practice on environmental preservation. The subjects of this study were 300 rural housewives living in Chung-buk province. Questionaires were distributed to them during a week from August $25^{th}$ to August $31^{th}$ in 1995. Major findings were as follows: 1. The saved water quite well in washing their faces and the dishes compared with urban housewives, but they did not save water so well in using the lavatory. They used synthetic detergent, one of water pollutants, more often than natural soaps in shampooing and laundering. In addition, they did not use a measuring cup. It resulted in the waste of detergent and aggravation of water pollution. 2. Food waste was disposed of properly, but used batteries were not collected separately. A disposable vinyl bag was more commonly used than a reusable shopping basket. The reason for not using a shopping basket was bothering or uncustomary. Since most of them did not know refillable products of goods with environmental mark, they did not use those. Therefore, housewives should be educated in order to prevent soil pollution. 3. The use of spry-type pesticide and hair treatment, one of air pollutants, was wide-spread among them. They hardly recognized and practiced saving of electric power when they used household electric appliances. 4. The major source of environmental knowledge was mass media like TV of radio. Many of them did not know the practical ways to solve the environmental education program. In conclusion, low level of recognition and practice of rural housewives on environmental preservation indicated that a systematic environmental education program should be developed and implemented.