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위상차(PDOA)를 이용한 열차 위치검지의 H/W 설계
정락교(R.G.Jeong),윤용기(Y.K.Yoon),조홍식(H.S.Cho),이병송(B.S.Lee),정상기(S.K.Chung),김영석(Y.S.Kim) 전력전자학회 2003 전력전자학술대회 논문집 Vol.2003 No.7(1)
TOA(Time of Arrival) 및 TDOA(Time Difference of Arrival) 경우 무선국의 시간동기화를 위해서 고도의 기술을 요구하고 있으며, 시간동기오차에 따른 위치검지의 정밀도가 낮아지는 문제가 있어 이를 극복하기 위하여 위상차(PDOA)를 이용한 새로운 열차검지기법의 제안에 따른 구현을 위하여 H/W의 설계에 대하여 기술하고자 한다. 본 시스템은 전파의 전달 속도(λ)를 응용하여 기준 주파수인 15MHz를 송신 시스템과 수신 시스템의 기준 주파수와 비교하여 그 위상의 차이를 비교하여 지연 된 시간을 구한 후 이를 거리로 환산하는 시스템으로서 H/W와 S/W로 구분하여 구현.설계 되는데 본 논문에서는 H/W설계에 대하여 기술하였다.
경량전철시스템의 회생용 인버터 모의방안 및 설치에 대한 경제성 검토
정상기(Chung S.G),한석윤(Han S.Y),이안호(Lee A.H),정락교(Jeong R.G),조홍식(Cho H.S) 한국철도학회 2003 한국철도학회 학술발표대회논문집 Vol.- No.-
최근의 도시철도 추진시스템은 VVVF 인버터로 제어되기 때문에 대부분 회생제동의 기능을 갖추고 있다. 회생제동 시 발생되는 전력은 그 때와 동일 노선에서 역행하고 있는 열차에 추진에너지로 사용되는 것이 가장 효율적이나 그것이 가능하지 않을 경우 혹은 그렇게 사용하고도 남는 잉여희생에너지가 발생할 경우 변전소의 회생용 인버터를 통해 역사 내에서 소비되는 방법도 많이 응용되고 있다. 이를 위해서는 회생용 인버터가 변전소 내에 설치되어야 한다. 본 논문에서는 경량전철시스템의 급전 시스템에서 이러한 회생용 인버터의 경제성분석과 적정용량 및 위치에 관에 논의된다.
조봉관(B. K. Cho),황현철(H. C. Hwang),류상환(S. H. Ryu),조홍식(H. S. Cho) 대한전기학회 2008 대한전기학회 학술대회 논문집 Vol.2008 No.10
Much signaling equipments are installed along railway tracks, and these are working in cooperation with each other, referring to other signaling equipment status. Existing railway signaling system uses signal cables to transmit this information. This system requires high cost for construction and have the problems like many faults from mistakes in cable connection, etc. To solve these problems, JREast Inc. has developed a new signaling system based on network technology, utilizing Ethernet-Passive Optical Network(E-PON). In this paper, we review the system proposed by JREast Inc. and field test results performed on railway.
조봉관(B. K. Cho),류상환(S. H. Ryu),황현철(H. C. Hwang),조홍식(H. S. Cho),이호용(H. Y. Lee) 대한전기학회 2008 대한전기학회 학술대회 논문집 Vol.2008 No.4
The level crossing collision accident which comprises more than 90 percent of all level crossing accidents is one of the most serious safety problems. There is a critical need for providing safe strategy and is focusing on the level crossing information rather than measures at a grade crossing. This study is intended to develop technology for accident prevention and damage reduction based on accident cases analysis result and improvement direction to complement shortcomings of safety equipment of conventional level crossing and to establish safety of travelers(train, motor vehicle, person).
정락교(Jeong R.G),백종현(Back J.H),조홍식(Cho H.S),정상기(Chung S.G) 한국철도학회 2003 한국철도학회 학술발표대회논문집 Vol.- No.-
In order to scheme the optimal assumption that satisfies the travel demand, it should be review the elements that affect on determining the headway, which are signal systems, line shape, vehicle(Light Rail Transit) performance, and so on. When applying the conventional signal systems, including Fixed Block System and Moving Block System, It was confirmed whether or not satisfy the requirements of target line with the way of a numerical formula reviewing and Train performance Simulation on the main line, station, depot, and so forth. Therefore, it should be used as references that decide target line and each sub-system after identifying the compliances for Minimum Headway to Moving Block System.
조홍식,한대상,박진영,김종민,박지선,김광,장상목 동아대학교 생산기술연구소 1999 生産技術硏究所硏究論文集 Vol.4 No.2
In this study, we investigated the reaction characteristics of polyurethane synthesis by measuring simultaneously resonant frequency and resonant resistance with a quartz crystal analyzer. Polyurethane synthesis gives the rapid decrease of resonant frequency by automatic catalyst effect due to the production of polyurethane at the initial stage. In prepolymer(PP) synthesis, the resonant frequency is slowly stabilized after the rapid decrease at any point of time. But in segmented polyurethane synthesis that chain-extender was added, the resonant frequency increased again after the rapid decrease at any point of time. It is believed that this tendency takes place because the chain-extender, 1,4-butandiol, changes soft segment into hard segment. As the result, we suggest that the reaction characteristics of polyurethane synthesis can be analyzed in on-line using a quartz crystal analyzer, and the systhesis mechanism can also be interpreted.
조홍식,송성훈,박진영,한대상,장상목 동아대학교 생산기술연구소 1999 生産技術硏究所硏究論文集 Vol.4 No.2
This paper shows the properties in various solution of a quartz crystal coated with carbon on a side of Pt electrodes by the method of high temperature and high pressure. In adsorption experiment, resonant frequency shift with time is measured in various aromatic solution(0.1, 1 mM β –Ionone and Methone, respectively). Furthermore, the results of measuring simultaneously current and resonant frequency in the solutions of 0.01 M NaCl, KCl and Mgcl_2of using a carbon quartz crystal as a working electrode by the method of cyclic voltammetry, are compared with those of using an Au quartz crystal. As this result, the aromatic compound, β –Ionone and Menthone, showed the steep resonant frequency shift by the surface adsorption at the initial stage, then the resonant frequency was slowly decreased by the diffusion inward the carbon pores. In the result of electrochemical experiment, It is possible to measured the effect of an objective anion after adsorbing a metal ion.