http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
CDMA/TDD 시스템에서 터보 부호를 사용한 H-ARQ 기법 연구
조성철,조대순,이유로,정인철,어윤,권동승,Cho, S.C.,Cho, D.S.,Lee, Y.R.,Jeong, I.C.,Uh, Y.,Kwon, D.S. 한국전자통신연구원 2001 전자통신동향분석 Vol.16 No.6
IMT-2000에서 제공하고자 하는 인터넷 서비스나 멀티미디어 서비스를 위하여 고속 패킷 전송이 이루어 져야 한다. 이러한 고속 패킷 서비스의 경우 불연속적인 데이터의 전송 및 비대칭적 데이터 트래픽의 특성으로 인하여 최근 CDMA/TDD 시스템에 대한 연구가 관심의 초점이 되고 있다. 따라서 본 고에서는 TDD 방식을 사용한 시스템의 특성을 고려하여, 전송 프레임의 구성 방식, 오류 발생 프레임의 재전송 방식, 채널 부호화 방식 등에 대하여 고찰하도록 한다.
조성철,엄주홍,이태형,Cho, Sung-Chul,Eom, Ju-Hong,Lee, Tae-Hyung 한국조명전기설비학회 2007 조명·전기설비학회논문지 Vol.21 No.8
가스방전관(GDT)은 내부 정전용량이 작아서 통신용 서지보호기로 널리 사용되고 있는 소자이다. 하지만 가스방 전관의 동작개시를 위해서는 방전이 개시될 수 있는 충분한 전압과 시간이 필요하며, 이 동작개시전압은 피보호 회로가 서지에 민감한 장비일 경우 손상을 줄 수 있을 만큼 크므로 최근에는 조합 형태로 적용하는 경우가 대부분이다. 이렇게 초기 과전압이 상당 부분 존재하는 가스방전관에는 추가적으로 TVS나 필터 등을 통해 피크 전압을 제한해 주어야 한다. 본 논문에서는 공통모드 초크코일을 이용한 필터를 적용하여 공통모드와 차동모드의 조합회로를 구성하고, 주파수 대역이 다른 뇌임펄스 전압과 ring wave 전압을 인가하여 파형에 따른 조합회로의 특성을 확인하였다. 다단으로 보호되는 과정을 각각의 측정점에서 잔류전압을 측정하여 단계별로 적용한 SPD들이 어떻게 동작하는지를 실측데이터로 제시하였다. 각 단계의 잔류전압을 비교했을 때 공통모드에 비하여 차동모드에서 서지전압을 제한하는 성능이 보다 효과적이다. Gas Discharge Tubes (GDTs) are widely used as surge protectors for communication applications due to their small internal capacitance. In these days, however, they are mostly used in combined configurations, because the sparkover voltage required to initiate the discharge process in the GDTs and the time taken for arc formation process can be large enough to damage to sensitive circuits. For GDTs with a considerably high initial residual voltage, we should limit the peak voltage using a TVS or filter. We made a hybrid SPD circuits of common-mode type and differential-mode type with the filter using common-mode choke. Also, we applied lightning impulse voltage and ring wave voltage which frequency bandwidth are different each other and verified the characteristics of hybrid SPD circuits according to waveshapes. We describe how the applied SPDs operate in protection process steps with the actual data obtained from the residual voltage measurement at each step. The experiment results show that the surge voltage reduction with the choke coil is more effective in differential-mode circuit than in common-mode circuit.
조성철(Sung-Chul Cho),이태형(Tae-Hyung Lee),엄주홍(Ju-Hong Eom),이복희(Bok-Hee Lee) 한국조명·전기설비학회 2010 한국조명·전기설비학회 학술대회논문집 Vol.2010 No.5월
This paper presents distribution ratio analysis of lightning current using small-scaled earth-termination system model of the structure. According to methods for connecting between clown-conductor and bonding bar, tests has been carried out on four test conditions. In result, distribution ratio of lightning current mainly depends on ground resistance of conductors connecting to bonding bar and methods for connecting between down-conductor and bonding bar.
실규모 구조체 모델에서 접지시스템의 뇌격전류 분류율 분석
조성철(Sung-Chul Cho),이태형(Tae-Hyung Lee),엄주홍(Ju-Hong Eom),이복희(Bok-Hee Lee) 한국조명·전기설비학회 2010 한국조명·전기설비학회 학술대회논문집 Vol.2010 No.9월
This paper presents distribution ratio analysis of lightning current using real-scaled earth-termination system model of the structure. The effective schematic of experimental model was taken to simulate current distribution for other conditions, and current distribution were analyzed with two current sources of both AC and impulse. In this result, when the lightning current flows in the earth termination system at the AC source was less than 50 %, the lightning current at the impulse source may more than 50 % .
공통접지시스템에서 본딩 방식에 따른 뇌격전류의 분류율 분석
조성철(Sung-Chul Cho),이태형(Tae-Hyung Lee),엄주홍(Ju-Hong Eom),권기량(Ki-Ryang Kwon),이복희(Bok-Hee Lee) 대한전기학회 2010 대한전기학회 학술대회 논문집 Vol.2010 No.7
This paper presents the investigation of surge current distribution in LPS(lightning protection system) during direct lightning strike to lightning rod in the building. In order to analyze surge current distribution, a small-scaled model and CDEGS program were used. Test results are consist of four cases, those are divided by bonding methods of between bonding bar and down-conductor in case of using down-conductor and framework of the structure respectively. Surge current distribution in a common ground system with multiple paths to earth was analyzed by considering whether the water pipe is bonded to common grounding system or not.
조성철(Sung-Chul Jo),이태형(Tae-Hyung Lee),엄주홍(Ju-Hong Eon),이복희(Bok-Hee Lee) 대한전기학회 2006 대한전기학회 학술대회 논문집 Vol.2006 No.7
Wenner 4-probe arrangement is used most widely by the method to measure soil resistivity and the measured data with the Wenner method are apparent resistivities of the soil. Therefore, the soil structure can be analyzed easily from the measured apparent resistivity, but the real soil resistivity is difficult to know correctly at a particular depth or at a specific location on earth surface. This paper introduces a method that can be used to decide the suitable burial depth and the electrode scale of a grounding rod effectively using soil structure analysis equipment based on the dipole-dipole method.
조성철(Sung-Chul Cho),이태형(Tae-Hyung Lee),엄주홍(Ju-Hong Eom),이복희(Bok-Hee Lee) 한국조명·전기설비학회 2011 한국조명·전기설비학회 학술대회논문집 Vol.2011 No.11
Distribution characteristics of conductive EMI currents by lightning in the structure was presented in this paper. To analyze a distribution of conductive currents, both experiment using the real size structure model and simulation using CDEGS HIFREQ program were performed. Test conditions which was possible to be appled to an installation method were considered. In results, some installation methods were effective at reducing conductive EMI currents flowing along vertical and horizontal rods in structure.
공통 접지시스템에서 뇌격전류의 분류율 계산을 위한 등가접지임피던스
조성철(Sung-Chul Cho),이태형(Tae-Hyung Lee),엄주홍(Ju-Hong Eom),이복희(Bok-Hee Lee) 한국조명·전기설비학회 2011 한국조명·전기설비학회 학술대회논문집 Vol.2011 No.5월
This paper presents a new method for calculating the distribution ratio of lightning current between each current sharing paths in common grounding system, which is need to allow for the equivalent grounding impedance. The equivalent grounding impedance calculated with the equivalent frequency of lightning current includes the transient characteristics of the grounding electrode considering circuit parameters of R, L, C, G. When the calculated distribution rates are compared with test results, the method using the equivalent grounding impedance is more effective than the method using only the grounding resistance.