• Journal of Electrical Engineering and Technology
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• 제11권3호
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• pp.775-780
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• 2016

This induced voltage measurement test and electromagnetic field simulation are related to the possibility of control signal malfunction by power line. Through an experiment, this research analyzed whether the voltage causing control malfunction according to the on/off status of power permitted to power line was induced to control signal line. Also, the research calculated the voltage induced to control signal line and examined the phenomenon by conducting an electro-magnetic field-specific simulation through the finite element method for the cable model used in the experiment.

• 한국정보통신학회논문지
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• 제14권6호
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• pp.1331-1337
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• 2010

본 논문에서는 국방과학의 RF 스텔스 구현을 위해 필요한 RCS 감소용 RAM의 전파흡수능 측정기법에 대하여 연구하였다. 먼저 RAM의 전파흡수능에 대한 이론 정립 후 측정기법에 대하여 실제 레이더 시스템과 유사한 자유공간법과 실험실에서 용이한 전송선로법을 분석하여 실제 RAM 샘플을 제작하여 측정기법에 따라 측정후 비교 분석하였다. 비교 분석결과 전파흡수능은 자유공간법에서 다소 우수한 특성이 보였으나 전체적인 패턴이 유사한 것을 확인하였다. 따라서 RAM 개발시 초기단계부터 최종단계까지 단계별/주파수별 제시하는 측정기법을 차등 적용한다면 보다 효과적으로 RAM을 개발 할 수 있을 것이다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2010년도 춘계학술대회
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• pp.527-530
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• 2010

본 논문에서는 RCS 감소용 RAM의 흡수능 측정기법에 대하여 연구하였다. 먼저 측정기법 중 자유공간법과 전송선로법을 분석하고 실제 RAM 샘플을 제작하여 측정기법에 따라 측정 후 비교 분석하였다. 비교 분석결과 흡수능은 자유공간법에서 다소 우수한 특성이 보였으나 전체적인 패턴이 유사한 것을 확인하였다. 따라서 RAM 개발시 초기단계부터 최종단계까지 단계별/주파수별 제시하는 측정기법을 차등 적용한다면 보다 효과적으로 RAM을 개발 할 수 있을 것이다.

• 한국해양공학회지
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• 제35권4호
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• pp.266-272
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• 2021

Mooring systems are among the most important elements employed to control the motion of floating offshore structures on the sea. Considering the use of polymer material, a new method is proposed to address the creep characteristics rather than the method of using a tension load cell for measuring the tension of the mooring line. This study uses a synthetic mooring rope made from a polymer material, which usually consists of three parts: center, eye, and splice, and which makes a joint for two successive ropes. We integrate the optical sensor into the synthetic mooring ropes to measure the rope tension. The different structure of the mooring line in the longitudinal direction can be used to measure the loads with the entire mooring configuration in series, which can be defined as SMART (Smart Mooring and Riser Truncation) mooring. To determine the characteristics of the basic SMART mooring, a SMART mooring with a diameter of 3 mm made of three different polymer materials is observed to change the wavelength that responds as the length changes. By performing the longitudinal tension experiment using three different SMART moorings, it was confirmed that there were linear wavelength changes in the response characteristics of the 3-mm-diameter SMART moorings. A 54-mm-diameter SMART mooring is produced to measure the response of longitudinal tension on the center, eye, and splice of the mooring, and a longitudinal tension of 100 t in step-by-step applied for the Maintained Test and Fatigue Cycle Test is conducted. By performing a longitudinal tension experiment, wavelength changes were detected in the center, eye, and splice position of the SMART moorings. The results obtained from each part of the installed sensors indicated a different strain measurement depending on the position of the SMART moorings. The variation of the strain measurement with the position was more than twice the result of the difference measurement, while the applied external load increased step-by-step. It appears that there is a correlation with an externally generated longitudinal tensional force depending on the cross-sectional area of each part of the SMART mooring.

• Journal of Electrical Engineering and Technology
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• 제7권1호
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• pp.103-108
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• 2012

The present study describes the considerations on the long-term reliability of the on-line partial discharge (PD) ceramic sensor for thermal power generators. Voltage acceleration aging tests were carried out under continuous and impulsive thermal aging at more than $100^{\circ}C$, considering the practical service environment. Experimental results show that the sensors have a life that could last for more than 100 years, excellent dielectric characteristics, and insulation strength. In addition, the ceramic on-line PD sensors were installed in a thermal power generator in Korea for demonstration. The results of the PD calibration and test voltage application prove that the on-line ceramic sensors have satisfactory performances for on-line PD measurement.

• Journal of Electrical Engineering and Technology
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• 제12권2호
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• pp.533-540
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• 2017

Distance relay identifies the type and location of fault by measuring the transmission line impedance. However any other factors that cause miss calculating the measured impedance, makes the relay detect the fault in incorrect location or do not detect the fault at all. One of the important factors which directly changes the measured impedance by the relay is series capacitive compensation (SCC). Another factor that changes the calculated impedance by distance relay is fault resistance. This paper provides a method based on the combination of distance and differential protection. At first, faulty transmission line is detected according to the current data of buses. After that the fault location is calculated using the proposed algorithm on the transmission line. This algorithm is based on active power calculation of the buses. Fault resistance is calculated from the active powers and its effect will be deducted from calculated impedance by the algorithm. This method measures the voltage across SCC by phasor measurement units (PMUs) and transmits them to the relay location via communication channels. The transmitted signals are utilized to modify the voltage signal which is measured by the relay. Different operating modes of SCC and as well as different faults such as phase-to-phase and phase-to-ground faults are examined by simulations.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1990년도 춘계학술대회
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• pp.43-46
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• 1990

Modern society is prevailed a lot of allergies. So, the allergy test is very important. There are many kinds of allergy test. A doctor usually uses skin allergy test among many allergy tests. However, little standadization and objectivity of grading-standard has been established in the skin allergy test. A measurement of the reaction area has been a major objective to perform skin allergy test. Recently, a doctor's method is to measure the reaction area after drawing a line that represents the reaction area on the skin. But this method differs slightly from the real reaction area and individual doctor's measurement is different, because the edge of the reaction area is obscure. In this paper, we propose a algorithm which is able to detect vague edges using the fuzzy set. The algorithm that detects the line and curve is proposed first. Here, the maximum value is calculated by comparing the membership function of the line and curve seperately. We also encode the direction of the line and curve by using 8-direction code. Then, we calculate the reaction area by measuring the pixels which are inside the reaction area. And finally the Allergy grade is decided by grading-standard, and we accomplish faster, the 80re accurate and objective allergy grade decision.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(2)
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• pp.57-60
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• 2002

In this paper, transmission lines with low and high characteristic impedance (Z$_{0}$) are fabricated and analyzed. The transmission lines are fabricated on the benzo-cyclo-butene (BCB) films of a low dielectric constant. For the low Z$_{0}$, two types of coplanar waveguide (CPW) structures are fabricated, which include bottom-ground and double-ground type. Measurement shows that Z$_{0}$ values for each CPW type are 7.3 and 9.4$\Omega$, respectively, at a signal line width of 100 #m. Whit the ratio between the spacing of bottom-ground and the signal line with becomes greater than 2.5, the Z$_{0}$ is nearly saturated. In addition, thin film microstrip lines fabricated using the BCB insertion layers show very low Z$_{0}$ of 25.5$\Omega$, and this impedance is ~64 % of the values obtained from the BCB-based CPW structures of the same line width. Measurement result of CPW on BCB layer is 100.5 Ω.s 100.5 Ω.

• 정보통신설비학회논문지
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• 제9권2호
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• pp.35-41
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• 2010

The balance coefficients between telecommunication lines are specified in the technical standard and the power induction computation method varies in the order of 100 times in magnitude according to the amount of impedance. The results of actual balance measurements, differing from time to time with the measurement circuit or increasing proportionally as the induction voltage increases, appeared as a measurement error because of not using the standard measurement circuit. This article investigates such errors and proposes the use of a standard balance measurement circuit and a measurement device impedance under the domestic notification standard and the ITU-T international standard.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제51권7호
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• pp.316-321
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• 2002

In this Paper, the channel characteristics of the medium voltage(22.9kV) power line to analysis the broadband power line communication in the frequency range up to 30MHz was measured. With the sideband electrical coupler in the operating frequency range from DC to 30MHz, we measured characteristic impedance, noise and attenuation of the medium voltage power line, and then characteristic impedance was measured at the state of unloaded medium voltage power line by Scattering parameter method of Vector Network Analyzer. As a measurement result, Channel impedance shows 100~380$\Omega$ at the less than 15MHz and 70~230$\Omega$ at the more than 15 MHz. Noise characteristics of power line shows -75dBm at 20MHz and Narrowband interference noise was from 3 MHz to 7MHz.