• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.3058-3060
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• 2005

In this paper, the CMOS four-quadrant analog multipliers for low-voltage low-power applications are presented. The circuit approach is based on the characteristic of the LV (Low-Voltage) composite transistor which is one of the useful analog building blocks. SPICE simulations are carried out to examine the performances of the designed multipliers. Simulation results are obtained by $0.25{\mu}m$ CMOS parameters with 2V power supply. The LV composite transistor can easily be extended to perform a four-quadrant multiplication. The multiplier has a linear input range up to ${\pm}0.5V$ with a linearity error of less than 1%. The measured -3dB bandwidth is 290MHz and the power dissipation is $37{\mu}W$. The proposed multiplier is expected to be suitable for analog signal processing applications such as portable communication equipment, radio receivers, and hand-held movie cameras.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2007.06a
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• pp.263-266
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• 2007

오늘날 다양한 Portable Mobile 기기의 출시와 함께 중요성이 부각되고 있는 부품의 하나로 전지가 인식 되어지고 있다. 하지만 전지의 형태는 외부로 드러나지 않고, 내부에서 심장과 같은 역할을 수행하고 있어 많은 사람들의 관심을 모으기는 어렵다. 휴대기기의 다양화, 복합화로 용량과 안전성이 한층 강조되고 있고, Set와 함께 수명을 지속하면서, 소비자의 다양한 요구에 대한 욕구충족과 함께, Set의 오용에도 안전하게 성능을 유지 할 수 있는 연구가 지속되어 오고 있다. 이에 본 연구는 무거운 휴대기기의 낙하 시 발생할 수 있는 전지 격리막의 변형으로 의한 발열에 대하여 실용 TRIZ의 6단계를 적용하여 원인분석 및 이에 대한 해결책을 제시하고자 한다.

• ETRI Journal
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• v.28 no.6
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• pp.732-738
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• 2006

In this paper, novel CMOS pseudo-exponential circuits operating in a class-AB mode are presented. The pseudo-exponential approximation employed is based on second order equations. Such terms are derived in a straightforward way from the inherent nonlinear currents of class-AB transconductors. The cells are appropriate to be integrated in portable equipment due to their compactness and very low power consumption. Measurement results from a fabricated prototype in a 0.5 ${\mu}m$ technology reveal a range of 45 dB with errors lower than ${\pm}0.5$ dB, a power consumption of 100 ${\mu}W$, and an area of 0.01 $mm^2$.

• Journal of the Korean Society of Combustion
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• v.15 no.2
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• pp.27-33
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• 2010

Recently, much attention has been paid to utilizing highly preheated air up to $1,000^{\circ}C$ through waste gas in industrial furnaces. The regenerative burner technology has shown to provide significant reduction in energy consumption (up to 60%), downsizing of the equipment (about 30%) and lower emissions (about 30%) while maintaining high thermal performance of the system since 2000. The object of this study is to develop the flameless regenerative burner for industrial furnaces based on the FLOX(Flameless Oxidation) principle and it has been designed and manufactured as pilot scale. Performance tests are experimentally done and their results are discussed. They showed 1) a very good uniformity in temperature distribution, 2) about 100 ppm in NOx at the temperature $1,300^{\circ}C$, 3) about 95% in temperature efficiency. Besides, the regenerative burner has advantage in easy maintenance and high usage rate of regenerator due to the separate and portable type of heat exchanger.

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.371-374
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• 1987

For this study, in order to reduce a measuring error. author used a portable radio mise measuring and processing equipment especially designed. The time & frequency characteristics of HF band radio noise fran the sample site in Yeungnam region had been accomplished and statistical analysis carried out at the site. The results had been compared with the distribution chart of an atmospheric noise :indicated in the CCIR Report 322 issue. It showed that type of a measured noise distribution was similiar to that of the report but the man-made noise had a remarkable effect on the characteristic curves of HF band radio noise about the site.

• Journal of The Korean Digital Architecture Interior Association
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• v.3 no.1
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• pp.59-62
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• 2003

The death from suffocation due to the gas from various disaster is frequent very and it occurs. Specially only from the company which treats the gas and only the enterprise which maintains the gas the many greeting accident occurs. Also accidents could occur when working around the toxic gas without one's noticing Therefore a development of the portable gas ditectoror is very essential. Specially with development of design and the new product of the electric chemical sensor might help reducing the many accidents. From the side which protects a worker's life, it isn't just simple equipment but also it must be connected directly to life saving is very important. Therefore, the key technical contents of development must be focused on sensor which is simple and easy to carry and able to detect varieties of toxic gas. So, this study is about the product design which is simple and easy to carry and to use.

• Proceedings of the IEEK Conference
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• 2000.07a
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• pp.225-228
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• 2000

It is well known that a Frequency Domain Adaptive Filter (FDAF) converges faster than a Time Domain Adaptive Filter (TDAF) even when the input signal is colored such as a speech signal. We have proposed the FDAF using the Modified Discrete Fourier Transform Pair (MDFTP) and its realization and effectiveness has been confirmed through the computer simulations. In this paper, we apply the FDAF using the MDFTP to the noise cancellation system. The proposed system is based on the Adaptive Line Enhancer (ALE) and utilizes single microphone; therefore it is suitable for the portable electronic equipment. Moreover, we propose to utilize the MDFT for detecting of the pitch in the speech because the number of data points in the MDFT must be equal to the pitch to confirmed that the noise can be removed to near the level of SNR.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1776-1778
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• 2000

The demands placed on portable wireless communication equipment include low cost, low supply voltage, low power, dissipation, low noise, high frequency of operation, and low distortion. These design requirements cannot be met satisfactorily in many cases without the use of RF inductors. However, implementing the inductor on-chip has been regarded as an impractical task because of excessive substrate capacitance and substantial resistive losses due to metallization and the conductive silicon substrate. Hence, there is a great incentive to design, optimize, and model spiral inductors on Si substrate. So, we analyzed a chip inductors using electromagnetic analysis and established a set of design rules for rectangular spiral inductors.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.11 no.2
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• pp.94-101
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• 1997

This paper proposes the equalizing charger of series connected batteries which are controlled by the time-sharing method. One-chip microprocessor dectcts the terminal voltage of each battery and then determines the charging time inversely proportional to the terminal voltage so that it decrease the un¬balanced capacity. This system is compact and light, therefore it can be applied to portable equipment such as charger for electric vehicle. And it's so effective as to prevent from overcharging which causes their life to shorten.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.673-674
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• 2007

22.9KV-Y 배전선로의 특고압 수전설비에 계량장치로 부설되어 운영중인 계기용변성기 M.O.F(Metering Out Fit)는 계기용변압기와 계기용변류기를 하나의 상자 속에 수납한 것으로 전력량계와 조합시켜서 전력측정의 변성장치로 사용되고 있다. 계량장치로 사용되고 있는 계기용변성기는 고객과 공정거래확립을 위하여 상시 정해진 비오차 특성을 만족하여야 한다. 그러나 고객구내 수전설비에서 파급고장이 발생시 과전류로 인하여 계기용변성기의 권선에 큰 충격이 가해져 비오차 특성에 문제점이 발생하나, 이 비오차를 측정할 때는 현재 정전상태에서 측정이 가능하여 현실적으로 측정을 할 수 없다. 이에 전기를 사용하는 활선상태에서도 비오차 측정을 할 수 있는 개발품에 대하여 고찰하고자 한다.