• Proceedings of the KIEE Conference
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• 2007.11b
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• pp.319-321
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• 2007

사회에서 지대한 관심과 논란의 대상이 되고 있는 한전의 고압전력 설비 중 송전선에서 발생하는 ELF(Extremely Low Frequency)전자계 저감을 위한 사회적비용의 계량화에 관한 연구를 하였다. 송전선로에서 발생되는 극저주파 전자계와 토지가격 사이의 관계론 규명하는 본 연구는 분서의 틀로서 극저주파 전자계 저감을 위한 다양한 기법에 대해서 제시하였다. 또한 다양한 황경가치 평가기법을 비교 분석한 결과, 헤도닉가격법이 가장 적정한 것으로 판단되어 이 분석법을 본 연구의 주된 분석도구로 삼고자 한다. 최근 환경질의 가치평가 기법으로 가장 광범위하게 사용되고 있는 기법중 하나인 헤도닉가격법은 기본적으로 주택, 토시 같은 재화는 그 자체가 가진 물리적 특성뿐만 아니라 외적인 환경 등 다양한 특성으로 이루어진 차별적 재화(differentiated product)라는 헤도닉가설(hedonic hypothesis)을 전제로 한다.

• Proceedings of the KIEE Conference
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• 1993.11a
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• pp.335-337
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• 1993

Offset voltage and drift characteristics of operational amplifier are critical factor to precision AID conversion System. In this study, a method is suggested to design the programmable A/D conversion system which has high resolution and low drift characteristics. First, hardware was designed to reduce the offset voltage of integrator and comparator, and analog switches are connected to reduce the drift characteristics of operational amplifier. And then, a calibration software technique was performed to obtain the stable data from A/D converter. The main advantage of our method is high precision A/D converter can be constructed with low cost and high confidence. Therefore proposed method is expected to be used in the industrial field where a high precision measurement is required.

• IEMEK Journal of Embedded Systems and Applications
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• v.4 no.2
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• pp.63-68
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• 2009

The location of mobile terminals in cellular networks is an important problem in the field of information technology with applications in resource allocation, location sensitive browsing, and emergency communications. Finding location estimation techniques that are robust to non-line of light (NLOS) propagation is a key problem in this area. Time of arrival (TOA) and pattern matching (PM) measurements can be made simultaneously by CDMA cellular networks at low cost. The different sources of errors for each measurement type cause TOA and PM measurements to contain independent information about mobile station (MS) locations. This paper combines the information of PM and TOA measurements to calculate a superior location estimate. The proposed location estimator is robust, provides lower error than the estimators based on the individual measurements, and has low implementation costs.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1466-1468
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• 1996

The standards of the capacitance arc measured and analyzed by the dry nitrogen or mica film as a dielectric. In this paper, respectively the standard capacitors of 10 pF and 100 pF for the establishment of the dielectric loss tangent are made by $Al_{2}O_{3}$ crystal disc with the low dielectric loss tangent, and then measured the dielectric loss tangent with precision. To regard for the existence of capacitances just in the dielectric, 3-terminal configuration electrode is used. With using the 2D electric field simulator, precise design values are derived in addition to stray capacitance. As stated above method, respectively the standards of the capacitances with 10 pF and 100 pF arc made with the low dielectric loss tangent less than $10^{-4}$.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.139-141
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• 1995

In this paper, we proposed digitalized low cost data logger system. In the past, data logger system which use analog method had many problems, inconvenience of measurement, unsatisfied accuracy, and had difficulty in storing data. Proposed system overcome these problems by using one-chip microcontroller which detects abnormal satus and saves it in RAM card. Saved data are transmitted to personal computer by serial communication port and by parallel interface card. Field experiment results validate the performances of the proposed system.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.6
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• pp.102-109
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• 2000

In this industrial induction motor speed and torque controlled drive system, the closed loop control usually requires the measurement of speed or position of amotor. However a sensorless drive of an induction motor has several advantages ; low cost and mechanical simplicity. Thus this paper investigates a field oriented control method without speed and flux sensors. The proposed control strategy is based on the Model Reference Adaptive System(MRAS) using a new flux estimator which replaces integrators with two lag circuits as the reference model. This algorithm may overcome several shortages of conventional MRAS such as integrator problems, small EMF at low speed. The simulation and experimental results indicate good speed responses.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.9
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• pp.676-680
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• 1999

To do breath alcohol measurement, a sensor is necessary that it can detect low alcohol gas concentration of 0.01% at least. In this work, a capacitance-type alcohol gas sensor using porous silicon layer is developed to measure low alcohol gas concentration. The sensor using porous silicon layer has some sensitivity at room temperature by very large effective surface area, but there is still much room for improvement. In this experiment, we measured the capacitance of the sensor under 254 nm UV light on the porous silicon layer, in which alcohol solution was kept in a flask at 25, 35, and $45^{\circ}C$ by a heater. As the result, the improvement of sensitivity by illuminating UV light was observed. The increasing rate of the capacitance was shown to be double more than those measured under UV-off state. It is supposed that UV light activates response of the oriental and interfacial polarizations which have slow relaxation time for AC field.

• Proceedings of the KSR Conference
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• 1999.05a
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• pp.200-207
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• 1999

The purpose of this research is to setup the design procedure of low noise rolling stocks. Noise sources are identified at a field test, and the contribution of noise sources to each part of car interior is ensured by sound intensity measurement technique. Added material to each section of the carbody makes it possible to identify absorption or reflection performance of each part to the anterior random noise. Such experimental tests to the exterior noise intruding through the floor represent that the best countermeasure on the floor is to implement reflecting material which can properly interfere noise. Design procedure of low noise rolling stocks is set through several experiments.

• Journal of Korea Multimedia Society
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• v.7 no.6
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• pp.767-780
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• 2004

Interaction requires dynamic relationship between objects. In ubiquitous computing environment, interaction between human and the environment is implied. Tactile interaction has so far been less addressed, while tactile sensation should be an important topic in the field of multimedia study. This paper describes development of a novel PVDF (Polyvinylidene Fluoride) dynamic tactile sensor and associated experiments. PVDF dynamic tactile sensors detect touch events applied to the sensor skin by low frequency components of the signal. Rubber skin-covered sensing material was mounted on the bones. Robust performance with low noise was figured out in our robotic experiment. Whereas most conventional sensors are interested in measurement, our dynamic tactile sensor is sensitive to change of state, which could be a key for economic understanding of happenings in the dynamic world. We note that dynamic sensing uses motion as a part of sensing modality We suggest that dynamic sensing be understood in technological terms in the perspective of interactive media and ubiquitous computing.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.594-603
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• 2018

Recently, according to the development of measurement techniques, it has become possible to take complicated and time-consuming field measurements in a simple and convenient manner. In this background, this study estimated the tension of cables under ambient vibration using minimized measurement and signal processing. The VBDM using video-only by low-cost equipment was used as a minimized measurement. An estimation of the natural frequency using the mirror frequency concept was also proposed to solve the shortage of frequency band in this case. Furthermore, the FDD method was adopted for a natural frequency estimation in the ambient vibration related to field application. Experimental studies using a cable-stayed bridge model were carried out to examine the properties of the mirror frequency and the applicability of FDD with the proposed minimized system. The results showed that FDD for ambient vibration also works properly in an estimation of the natural frequency using the minimized system. In addition, the mirror frequency concept can allow a high natural frequency estimation even in a distorted signal by low-speed recording, which can overcome the limit of the minimized system. Overall, the proposed minimized system can be effective for the tension estimations of a cable under ambient vibration.