• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.4
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• pp.425-432
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• 2014

Necessity of compact X-band solid-state weather radar is required to provide weather data, which generate locally in a lot of Korea's mountainous area, rather than tube-type radar. Solid State Power Amplifier (SSPA) for using Dual-polarization method in weather radar is able to obtain desired high output by combining many low output power devices in parallel. Thus, Power combiner applying to high-output power amplifier has disadvantages such as path loss, ballast resistance problem by high frequency and high power, heat release. Therefore, In this paper we demonstrated the excellence of isolation, which is the result from modified Gysel power combiner. As a result, we designed X-band 250W solid state power amplifier with peak power 54dBm, 25% power efficiency for weather radar.

• Journal of the Korea Society for Simulation
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• v.25 no.4
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• pp.77-84
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• 2016

This paper proposes a methodology for creating a function based reliability prediction model. Although, there are various works for reliability prediction, one of the features of their research is that the research is based on hardware-centered reliability prediction. Reliability is often defined as the probability that a device will perform its intended function, under operating condition, for a specified period of time, there is a profound irony about reliability prediction problem. In this paper, we proposed four-phase modeling procedure for function-centered reliability prediction. The proposed modeling procedure consists of four models; 1) structure block model, 2) function block model, 3) device model, and 4) reliability prediction model. We performed function-centered reliability prediction for electronic ballast using the proposed modeling procedure and MIL-HDBK-217F which is the military handbook for reliability prediction of electronic equipment.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.1
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• pp.31-37
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• 2017

In this paper, we implemented for the development of a high output induction lamp system, which lamp design is optimized by gas type, mixing ratio, pressure and discharge tube size, amalgam type and mixing ratio, and characteristics of ferrite core in the lamp. It's the circuit design by improving the power factor and efficiency according to the driving method, which has analyzing the characteristics according to the waveform and frequency. Finally, luminaries design part for applying the optimal lighting system considering the surrounding environment, the characteristics of the lighting circuit for electrodeless lamp has analyzed and the improvement has been proceeded. In conclusion, the driving frequency has optimized at 135kHz with degrading $7{\sim}10^{\circ}C$ based on the results of the optical characteristics of the induction lamp on peak noise FET(Q3,Q4) damage.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.15 no.6
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• pp.8-14
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• 2001

MetalHalid lamps have good efficiency, good color rendition and good focusing capability. But the shortcoming of metalhalid lamps is blown as acoustic resonance phenomena in the arc tube. Such acoustic resonance produce annoying fluctuations in the intensity and distribution of the emitted light, they can raise the voltage to the point where the arc is extinguished and they can move the arc close enough to the wall to cause local overheating and tube cracking. The objective of this research is to reduce acoustic resonance in the arc tube of the Pulse Start MetaIHaide lamp(MH200[W]). To reduce the acoustic resonance phenomena the electronic ballast was designed for high frequency operation with the constant frequency sinusoidal wave of 89[kHz] in the 84.6[kHz]∼94.2[kHz] range. Experimental results show that the acoustic resonance phenomena are not in the arc tube of Pulse Start MetalHalide lamp (MH200[W]) .

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.4
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• pp.691-700
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• 1994

A power line in not so good in characteristics for communication, because it is a media to transfer the commercial electrical power, and its load noise and high frequency noise are so much. Thus, a simple method to transfer a remote control signal on the power line is studied. The already-existing method is that two signals with upper part eliminated is transmitted every N step. But the method is investigated which the transmitter sends a period signal eliminated in arbitrary phase. Thus the transmission power loss due to elimination of signal can be reduced to the minimum. To implement it, a timer calculating the time from zero-crossing point to the phase is required. The micro-controller, 87C51, precisely calculates the phase using one of two built-in timers. As a result, a remote control signal tramsmitter and receiver using a partially eliminated signal, which is better than the conventional technique using half-eliminated signal in a efficiency of power transmission, is realized, and its characteristics are analyzed.