• 전력전자학회:학술대회논문집
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• 전력전자학회 2006년도 전력전자학술대회 논문집
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• pp.456-458
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• 2006

Power line communication: PLC which easy to install at anywhere near outlet for electric machine. PLC uses transmission line for voltage of which is 60 Hz. Signals don't affect to electric machine in PLC because they are very small voltage. One of the important thing is the processes of adding signal to power line and extracting the signal from power line, the other is to choose the strong modulation method which sends signals long distance without loosing in PLC channel. but PLC channel have very high and variable noise and attenuation and then it is very hard to transmit optimally between the transmitter and the receiver. After all, impedance and noise problems of PLC channel must be overcame. Noises of 2 kinds which are AWGN abd impulse noise and attenuation are orated. To overcome the noise. Recently, Multi-carrier Modulation: MCM methods like as OFDM and DMT which are divide the channel into many sub-channel have been studied. those are powerful communication methods in PLC. In this paper, PLC channels made up of 3 numbers of noise and attenuation are simulated for getting BER by Matlab simulink.

• 한국소음진동공학회논문집
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• 제11권4호
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• pp.13-21
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• 2001

Electrorheological(ER) fluid is a kind of smart material with variable shear stress and dynamic viscosity under various electric field intensity. Electric field can control the damping characteristics of ER damper. The objective of this study is the analysis of the performance of ER damper and its application to shock absorber. Idealized nonlinear Bingham plastic shear flow model is used to predict the velocity profile between electrodes. Cylindrical dashpot ER damper with moving electrode is constructed and tested under various electric fields. The analytic and experimental results for damping force are compared and discussed. Drop test system using ER damper is prepared to identify transient vibration characteristics. The rebound is eased as the applied electric field increases. When semi-active control algorithm is applied, rebound phenomenon disappears and vibration energy level decays faster than the case of zero electric field.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2007년도 춘계학술대회 논문집
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• pp.33-38
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• 2007

This paper presents a experimental evidence of the generation of the earth potential and communication line noise from the electric railway. There is a critical measurement err in case of measuring the electrical power induced noise voltage and degree of cable balance in the field of earth potential generated. As a results, it has been found that the conventional cable has more noise immunity than shielded cable near the railway where the earth current flows through the sheath layer.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 추계학술대회 논문집
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• pp.396-401
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• 2000

There are three examples of noise reduction test by rail welding. One of them is tested at electric car running area and another is tested at expansion joint and long welded rail and the third is tested at open deck bridge. We can know from the result that the noise reduction effect of rail welding is very different to the type of track and the car. The condition of the test has some differences, but it may be useful reference of noise reduction.

• Journal of Electrical Engineering and information Science
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• 제2권6호
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• pp.116-122
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• 1997

The audible noise produced by corona discharge in high voltage transmission lines is the most important line design consideration. In this paper, more accurate and useful formulas for predicting the A-weighted audible noise during heavy and light rain in alternative current (AC) transmission lines are proposed through comparison with the existing formulas. The proposed formulas are developed by the applications of evolutionary computations (ECs) to audible noise data base from long-term measurement.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.101-105
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• 2004

The traction drive have a high power transmission efficiency and small size, a light weight, a low noise. So it is expected that alternative drive part of engine. Because it is necessary stillness that essential condition of drive part used moving tool in a room, it has many-sided in field of application. This traction drive is better suitable than other speed reducer as drive part of electric wheelchair. Also it is sufficiently necessary capacity of existing advanced product as apply traction drive to electric wheelchair.

• 한국자동차공학회논문집
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• 제20권5호
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• pp.44-52
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• 2012

Fuel cell electric vehicles have some noise problems due to its air processing unit which is required to feed the ambient air into the fuel cell stack. Discrete-frequency noises are radiated from a centrifugal blower due to rotor-stator interaction. Their fundamental frequency is the blade passing frequency, which is determined by the number of rotor blades and their rotating speed. To reduce such noises, multi-chamber perforated muffler has been designed. In this paper, in order to improve the transmission loss of a perforated muffler, the relationship between the impedance model of a perforated hole and its noise reduction performance is studied, and the applicability of a short-length perforated muffler to air processing unit of fuel cell system is described using acoustic simulation results and experimental data. The acoustic velocity vector across the neck of a perforated hole is very important design factor to optimize the transmission of an intake muffler. The suggested short-length perforated muffler is effective on discrete-frequency noises while keeping the volume of intake muffler minimized.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.2224-2229
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• 2008

High-Speed train has been developed and it becomes faster and environmental friendly. As trains run faster, Noise of trains is generated mainly by aerodynamic disturbance. Pantograph, both ends of trains, and gaps of coaches which are thought to be aerodynamic noise's factors are primarily studied. Pantograph is a similarly shaped metal framework on the roof of an electric high speed train, transmitting current from an overhead electric catenary wire. Panhead which contacts electric wires directly looks like a bluff strut, goes through flows, is sensitive to external disturbances and is one of the most important factors which decide whole vehicles' driving ability. In this study, aerodynamically robust optimized pantograph panhead shape is designed and then evaluated through subsonic wind tunnel test. To compare these with existing panhead rectangular shapes or circular cylinder shapes, By visualizing strong vortex flow patterns which are main noise sources, characteristics are compared and analyzed

• 한국전자파학회논문지
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• 제25권10호
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• pp.966-982
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• 2014

본 논문에서는 고속 디지털 시스템에서 발생하는 잡음에 의해 RF 시스템의 특성이 열화되는 현상(RF interference: RFI)에 관한 시스템 레벨의 EMC 분석 기술과 주요 잡음원인 고속 디지털 시스템에서의 EMC 대책 기술을 소개하고 분석하였다. 현재 하나의 전자기기에서 시스템 간 발생하는 EMI/EMC 문제는 더욱 심각해지고 있으며, 특히 디지털 시스템의 EMI에 의한 RFI 문제는 주요 관심 문제로 인식되고 있다. 따라서 본 논문에서는 현재까지 연구되어진 부품 레벨부터 시스템 레벨까지의 RFI 연구에 대하여 소개하고 분석하였다. 그리고 이 문제를 해결하기 위해서 주요 잡음원 중의 하나인 고속 디지털 인터페이스에서 발생하는 공통모드 잡음의 발생 원인과 그에 대한 대책 연구에 관하여 분석하였다. 마지막으로, 앞으로 RFI 문제를 해결하기 위한 시스템 레벨의 EMC 분석 및 대책 연구방향을 제시하였다.

• 화약ㆍ발파
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• 제40권2호
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• pp.25-34
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• 2022

최근 터널 발파현장을 중심으로 정밀한 시차를 갖는 전자뇌관을 활용하여 시공성을 향상하는 사례가 증가하고 있다. 본 사례는 『수도권 광역급행철도 A노선 민간투자사업 제00공구』 현장에서 비전기뇌관과 전자뇌관을 혼용하여 시험발파를 수행한 사례로, 현장 주변 상업시설과 지하철 등 보안물건이 있어 발파작업 시 진동과 소음의 세심한 관리가 필요한 곳이다. 당 현장은 비전기뇌관으로 설계되었으나, 굴진율의 저하로 비전기뇌관과 전자뇌관을 혼용함으로써 굴진율을 향상하고 진동과 소음을 관리하고자 하였다. 시험발파 결과 굴진율이 약 85%로 목표치를 달성하였고 진동과 소음의 최대 측정값은 0.215cm/sec와 73.22dB(A)로 규제기준 이하로 계측되었다. 당 현장은 도심지에서 발파작업이 진행되는 만큼 계측관리 대상물을 지정하여 지속해서 진동과 소음을 관리할 필요가 있다.