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ATP시스템에서 열차속도에 따른 지상자에서 차상자로의 자계의 세기에 관한 연구
김민석(Kim Min-Seok),고준석(Ko Jun-Seog),이상혁(Lee Sang-Hyeok),김민규(Kim Min-Kyu),이종우(Lee Jong-Woo) 한국철도학회 2010 한국철도학회 학술발표대회논문집 Vol.2010 No.7
Electric railway system consist of rolling stock, track, signal and streetcar line system. ATP(Automatic Train Protection) system in railway signaling system is the important one grasping the position and velocity of a train. The wayside transmitter of ATP system is installed between rails. Recently, the research about increasing train speed has been developed in total departments of the railroad systems. The study on the information transmission between on-board transmitter and wayside transmitter is required for increasing the train speed in the ATP system. When the train speed is increased as to same transmission distance, the problem on information transmission occurs because the transmission time is decreased. In case that the transmission distance is extended, the transmission time is decreased with respect to the train speed. Therefore, we have to define the standard magnetic intensity as to the train speed in order to transmit correctly telegram. In this paper, the transmission distance for the telegram is suggested on the basis of the train speed. Also, the standard magnetic intensity from the wayside transmitter to on-board transmitter is proposed by using transmission distance regarding the train speed in the ERTMS/ETCS system by using Matlab program.
콘크리트 슬래브궤도에서 보상 커패시터의 위치 및 전기용량에 대한 연구
김민석(Kim Min-Seok),이상혁(Lee Sang-Hyeok),고준석(Ko Jun-Seog),이종우(Lee Jong-Woo),조수익(JO Su-Ik),유진영(Yu JIn-Young) 한국철도학회 2009 한국철도학회 학술발표대회논문집 Vol.2009 No.5월
Impedance of rails is increased by the magnetic coupling between rails and reinforcing bars in the concrete slab track. Currently, the current of track circuit has been compensated by installing the compensation capacitors on track circuit because of increasing the impedance of rails. In case of a rapid transit railway, the compensation capacitors are installed every 20[m] to compensate the current of track circuit in the concrete slab track. Because the interval of one block for a rapid transit railway is as long as 1500[m], the compensation capacitors are installed about the number of 70~75 on track circuit. However, in case the compensation capacitors are broken over the number of three, it is a problem that the amplitude of current is under standard amplitude of current which is 0.8[A]. In this paper, it was suggested installing a compensation capacitor by using resonance phenomenon on the concrete slab track. We represent the electrical model of track circuit and the four terminal network, calculate the parameters demanded for the electrical model in the concrete slab track. Also, we computed the position and capacitance of the compensation capacitor about 2040[㎐], 2400[㎐], 2760[㎐], 3120[㎐] which currently is the track circuit frequency in the Gyeongbu rapid transit railway and demonstrated the validity of it, using the Matlab and PSpice program.
콘크리트 슬래브궤도에서 ATP시스템 지상자의 주파수가 철근에 미치는 영향
김민석(Kim Min-Seok),이종우(Lee Jong-Woo),고준석(Ko Jun-Seog) 한국철도학회 2008 한국철도학회 학술발표대회논문집 Vol.- No.-
ATP(Automatic Train Protection) system in railway signaling system is the important one grasping the position and velocity of a train. The wayside transmitter of ATP system is installed between rails. In concrete slab track, the signal current using wayside transmitter of ATP system is influenced by reinforcing bars. The magnetic coupling between reinforcing bars and wayside transmitter of ATP system as a filter makes an input current distorted. So, it makes an alternating current signal with a desirable size not transmit to on-board system of a train. Way to decrease the distortion of an input current signal frequency is to avoid maximum induction current frequency. And the induction phenomenon between reinforcing bars insulated and wayside transmitter of ATP system does not occur. In this paper, we represent the model about wayside transmitter of ATP system and reinforcing bars on the concrete slab tracks, and calculated the parameters demanded for the model. Also, we demonstrated it through the Maxwell program. Furthermore, we calculated impedance on wayside transmitter used in KVB system and ERTMS/ETCS system which are a kind of ATP system, frequency response of induction current, using the Matlab, and demonstrated the validity of it, using the PSpice program.
고준석,강삼석,백영홍 대한신경외과학회 1995 Journal of Korean neurosurgical society Vol.24 No.6
This study was designed to observe anoxia-induced responses and to clarify their possible mechanisms in porcine basilar and circle of Willis arteries. Anoxia produced a transient vasoconstriction, which then recovered to the basal tension of a 3-5 min. later, and the reoxygenation that follows produced the biphasic(relaxation-contraction) response in the intact endothelial rings under resting tension. The anoxia-induced contraction was potentiated by pretreatment with KCl and PGF2α. Reoxygenation produced only sustained relaxation. Removal of the endothelium and pretreatment with nimodipine or indomethacine markedly attenuated the anoxia-induced contractions. Anoxia transiently and significantly increased cyclic GMP contents in the endothelium-intact preparations, but did not affect them in the endothelium-removed ones. The above results suggest that anoxia-induced contraction is endothelium-dependent and is resultant to the release of a Prostaglandin-like substance(s).