• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2007년도 학술대회
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• pp.211-214
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• 2007

Development of IT and electronics industries has make our life more convenient, yet at the cost of radio communication noise, malfunctioning of electronic appliance and risks against human health all resulting from EMI. Many states are tightening their EMI (Electro Magnetic Interference) regulations around the world and the EMI regulatory measures are likely to increase in terms of targets and types. Against this backdrop, this paper aims to introduce fundamental and adequate EMI countermeasures encompassing product production cycle from design to production stage.

• 전자통신동향분석
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• 제16권1호통권67호
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• pp.56-70
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• 2001

마이크로파대 이상의 높은 RF 전파는 신호레벨이 비교적 작고 간섭현상에 매우 민감한 특성을 가지고 있다. 따라서 이러한 미소한 입력전파의 수신시 수신기 전체의 감도를 높이고 잡음을 저감시킬 목적으로 사용되는 고주파 증폭기가 저잡음 증폭기이다. 본 고에서는 LNA의 기본적 특성분석과 지능형교통시스템에 응용되는 5.8GHz대 단거리전용통신용 LNA를 구현하기 위한 기본 FET 증폭기의 전기적 특성을 연구하고 직렬 궤환에 의한 최소잡음과 최소 입력 정재파비의 최적 설계 파라미터를 도출하였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.57-60
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• 1999

In many radio communication environments, there is a special component, called inter-symbol interference (ISI), mused by multipath time delay of signal and ISI components impose limitation of the data transmission rate. In this paper, we consider signaling pulse shapes, called partial response signaling (PRS), for minimizing the effect of ISI and show the improvement of performance by applying one of the partial-response signaling (PRS) pulses to two types of receiver system under dependent noise environments through the Monte-Carlo computer simulations.

• 한국조명전기설비학회지:조명전기설비
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• 제13권2호
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• pp.156-156
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• 1999

This paper describes the characteristics and the criteria of electrical environmental effects produced from power system especially transmission line. Audible noise radio and TV interference, electric and magnetic inductions which are main items for optimal conductor selection as well as major contributors to the community complaint of electrical environmental problem, are surveyed and studied comparing with the criteria or the environmental protection regulation of domestic and foreign countries. As a result a domestic criteria of electrical environmental on power system was suggested.

• 천문학회보
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• 제44권1호
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• pp.60.1-60.1
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• 2019

In this talk, I will briefly review the discovery and early-time interferometric observations of the Galactic Center radio source and then go through recent major updates including the improvement in the array capabilities, developments of the scattering and intrinsic structure modeling, and high-frequency astrometric observations of this source. Introduction of the 1.3 mm VLBI observations in 2017 and 2018 (e.g. array configuration and signal-to-noise ratios), as well as the related multi-wavelength campaign (including GMVA and EAVN observations), will be also presented.

• Journal of Communications and Networks
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• 제5권4호
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• pp.365-373
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• 2003

This paper investigates the performance of M-ary pulse position modulation (PPM) multiuser ultra-wideband (UWB) communication systems in terms of symbol error rate (SER) over fading and additive white Gaussian noise (AWGN) channel. Based on Gaussian approximation for the multiple access interference, an expression for the signal-to-noise ratio (SNR) is derived for the UWB system. This expression is used to derive exact SER expressions for coherent UWB receivers. The effect of pulse selection on the SER of multiuser UWB system is studied. In addition to rectangular pulse, the 2nd derivative Gaussian waveform and Rayleigh pulses were considered. We show that the system capacity and/or SER performance can be significantly increased by using the monocycle pulse in fading channels.

• ETRI Journal
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• 제32권2호
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• pp.255-264
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• 2010

Interference scenarios and methodologies between a terrestrial mobile service (MS) system and mobile-satellite service (MSS) system in a co-channel environment are established. Taking into account a practical deployment situation for both systems, we perform computational simulation of interference in terms of carrier-to-interference ratio (C/I) and interference-to-noise ratio (I/N) to evaluate the cofrequency interference from an MS system into an MSS system, and from an MSS system into an MS system, respectively. The methodology and results can be used as a guide when planning the deployment of MSS and MS systems with no unacceptable interference impact between them.

• Journal of Communications and Networks
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• 제16권1호
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• pp.92-97
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• 2014

A novel method for extracting frequency slippage signal from radar full pulse sequence is presented. For the radar full pulse sequence received by radar interception receiver, radio frequency (RF) and time of arrival (TOA) of all pulses constitute a two-dimensional information sequence. In a complex and intensive electromagnetic environment, the TOA of pulses is distributed unevenly, randomly, and in a nonstationary manner, preventing existing methods from directly analyzing such time series and effectively extracting certain signal features. This work applies Gaussian noise insertion and structure function to the TOA-RF information sequence respectively such that the equalization of time intervals and correlation processing are accomplished. The components with different frequencies in structure function series are separated using empirical mode decomposition. Additionally, a chaos detection model based on the Duffing equation is introduced to determine the useful component and extract the changing features of RF. Experimental results indicate that the proposed methodology can successfully extract the slippage signal effectively in the case that multiple radar pulse sequences overlap.

• 한국통신학회논문지
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• 제7권1호
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• pp.37-45
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• 1982

육상 移重무선통신상에 있어서 2相 DPSK 방식에 대한 가우스 잡음과 多重路 동일주파 간섭파의 영향에 관해 이론해석을 행했다. 해석방법으로서는 多重통신로는 비선택성 Rayleigh통신로로 간주, DPSK 검파기 출력의 確率密度雨數를 유도하여, DPSK방식의 수신誤率의 일반식을 구했다. 수치해석 결과로서 반송파대 잡음전력비(CNR)의 변화에 따른 수신誤率를 반송파대 간섭파전력비(CIR)와 희망신호의 상관계수를 파라메타로 하여 그림으로 나타내고 이를 분석, 검토했다.

• 한국소음진동공학회논문집
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• 제21권6호
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• pp.553-561
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• 2011

A theoretical approach is carried out to predict the quality factors of flexible modes of a microcantilever on a squeeze-film. The frequency response function of an inertially-excited microcantilever beam is derived using an Euler-Bernoulli beam theory. The external force due to squeeze-film phenomenon is developed from the Reynolds equation. Slip boundary conditions are employed at the interfaces between the fluid and the structure to consider the gas rarefaction effect, and pressure boundary condition at both ends of fluid analysis region is enhanced to increase the exactness of predicted quality factors. To the end, an approximate equation is derived for the first bending mode of the microcantilever. Using the approximate equation, the quality factors of the second and third bending modes are calculated and compared with experimental results of previously reported work. The comparison shows the feasibility of the current approach.