• 한국통신학회논문지
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• 제25권3A호
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• pp.417-423
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• 2000

A broadband antenna available in the range of 30MHz for electromagnetic interference (EMI) test is proposed in this paper, This antenna is configurated in a disk-loaded cylindrical dipole (DLCD) connected to an 180。 hybrid balun consisting of two coaxial feeders. The performance of EMI antenna is characterized with its accurate antenna factor. The antenna factor for this antenna is obtained by using the method of moments and the calculated results are compared with the measured ones. Normalized site attenuation (NSA) is also measured by using this antenna. The results present that the propose antenna could be used for a reference antenna having measurement reproducibility and represented by a theoretically accurate analysing model in EMI measurement.

• 한국소음진동공학회논문집
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• 제15권6호
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• pp.738-748
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• 2005

The ship radiated noise level fluctuates by the difference of interference and reverberation according to measurement methods and environmental conditions. These phenomena cause error of the source level estimation even in the same environment conditions. This paper describes a quantitative analysis and a reduction method for an error value to the source level estimation in spatial and temporal interference environment. The design criteria of the radiated noise measurement array composed of omni-directional hydrophones and the source level accuracy in the deep water range are given. The source level accuracy in the shallow water range is also derived based on the statistical model of the multiple reflection paths. The results are verified using the water tank experiment and the sea trial.

• 한국생산제조학회지
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• 제5권1호
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• pp.33-42
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• 1996

The high coherence of laser beam has made it possible to observe interference effects even in the light scattered from rough surfaces. That's why, when object with a scattering surface is illuminated with laser light, we do see a speckled appearance due to random interference. This sort of unique property of laser speckle has bruht into existence the new noncontaciting techniques such as speckle metrology method of measuring deformation, displacement, and vibration etc of objects with high optical sensitivity. The measurable range of speckle metrology especially used to measure in -plane information, however, is limited by some factors, the so-called strain, rotation tilt of surface and out of displacement perpendicular to the plane of analysis This restrictions severly limits the measurable range of speckle metrology by causing the decorrelation of speckle patterns. It is the purpose of this paper to give a survey on the measurable limitation of speckle photography method that is one of speckle metrology. Namely we will discuss the mutual relationships and problems of each limitations adding the restriction on the largest and smallest displacement measurable with speckle methods.

• Current Optics and Photonics
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• 제1권3호
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• pp.228-232
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• 2017

We propose a reflector-type perfect absorber with double absorption lines using electric and magnetic dipoles of Mie resonances in an array of silicon nanospheres on a silver substrate. In the visible range, hundreds of nanometer-sized nanospheres show strong absorption lines up to 99%, which are enhanced by the interference between Mie scattering and reflections from the silver substrate. The air gap distance between the silicon particles and silver substrate controls this interference, and the absorption wavelengths can be controlled by adjusting the diameter of the silicon particles over the entire range of visible wavelengths. Additionally, our structure has a filling factor of 0.322 when the absorbance is nearly 100%.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(5)
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• pp.113-116
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• 2000

In this paper presents the portable wireless ECG data detection and diagnosis system based on discreet wavelet transform. An algorithm based on wavelet transform suitable for real time implementation has been developed in order to detect ECG characteristics. In particular, QRS complex, S and T waves may be distinguished form noise, baseline drift or artifacts. Proposed telemetry system that a transmitting media using radio frequency(RF) for the middle range measurement of the physiological signals and receiving media using optical for electromagnetic interference problem. A standard hi-directional serial communication interface between the telemetry system and a personal computer or laptop, allows read-time controlling, diagnosing and monitoring of system. A portable telemetry system within a size. of 65${\times}$125${\times}$45mm consists of three parts: a digital signal processing part for physiological signal detect or diagnose, RF transmitter for data transfer and a optical receiver for command receive. Advantages of proposed telemetry system is wireless middle range(50m) FM transmission, reduce electromagnetic interference to a minimum. which enables a comfortable diagnosis system at home.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
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• pp.604-608
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• 2003

In this paper, we studied the radiated electric field of power-line with DMT signal source in the frequency range of $1.7{\sim}30 MHz$. First, we made the midium voltage power-line communication model for PLC and calculated the current through the power-line using the impedance of the power-line model. Second, we calculated the radiated electric field in power range $-50{\sim}-30 dBm$ using the calculated current. Consequently, the calculated emissive electromagnetic field from the DMT signal is similar to the measured result. So this study is applicable to the standard regulation of electromagnetic interference for PLC.

• 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.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1999년도 춘계학술대회 논문집
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• pp.170-174
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• 1999

The main scale of linear scale greatly affects on the precision of displacement measurement. Especially when needing the long range measurement, the length of main scale should be increased accordingly. In this paper, we propose a linear scale that uses laser interference pattern as main scale for long range measurement. The linear scale is similar to Michelson interferometer excepting that the reference mirror is tilted so as to obtain interference fringe pattern and a grating panel is attached on a quadratic photo diodes. Four kinds of grating having phase differences of 0, $\pi$ /4, $\pi$ /2, 3 $\pi$ /4 are arranged on the panel. The experimental results show that signals of - quadratic photo diode, A, B,$\overline{A}$ and $\overline{B}$ are cosine wavelike and successive signals have phase difference of $\pi$/4 each other. So the proposed method can achieve improved measurement resolution.

• 대한의용생체공학회:의공학회지
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• 제21권5호
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• pp.513-517
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• 2000

본 논문에서 제안한 텔레메트리 시스템은 생체신호를 증거리로 전송하기 위한 RF 송신기와 전자파 간섭의 영향이 없는 광을 매체로하는 수신기로 구성된 시스템이다. 따라서 텔레메트리 시스템은 RF 송신부, 광 수신부 및 생체신호 처리를 위한 CMOS 원칩으로 구성되어있으며, 65$\times$125$\times$45mm의 크기이다. 제안된 텔레메트리 장점은 전자파에 노출을 최소화하면서 중거리(50m) 텔레메트리가 가능하여, 자유로운 상태에서의 모니터링이 가능하다.

• 한국전자파학회논문지
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• 제18권7호
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• pp.731-738
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• 2007

최근 UHF 대역에서 동작하는 RFID 시스템이 활발히 연구되고 있으며, 유통 물류 분야를 시작으로 다양한 분야에서 사용되고 있다. 본 연구에서는 UHF RFID 시스템의 주파수 간섭 중 RFID 시스템 설계시 가장 문제가 되고 있는 리더간 간섭을 인식 거리 측면에서 분석하였다. RFID 주파수 간섭를 정량적으로 분석하기 위하여 새로운 성능 지표로 IRRR을 정의하고, IRRR의 유용성을 보이기 위해 두 개의 RFID 리더와 하나의 태그로 구성된 측정 시스템을 구성하여 IRRR이 실제 환경의 특성을 반영하고 있음을 확인하였다. 따라서, 실제 다양한 RFID 시스템을 설치할 때 IRRR을 설계 파라미터로 사용함으로써 주파수 간섭 문제를 해결할 수 있을 것이다.