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DS/CDMA시스템에서 역방향 링크 동기식 전송 기법의 성능과 핸드오버 영향을 고려한 성능 분석
안병철,황선한,홍인기,조경록,유영갑,An, Byeong-Cheol,Hwang, Seon-Han,Hong, In-Gi,Jo, Gyeong-Rok,Yu, Yeong-Gap 대한전자공학회 2000 電子工學會論文誌-TC (Telecommunications) Vol.37 No.2
DS-CDMA시스템은 다중 접속 간섭(Multiple Access Interference; MAI)에 의해 주로 성능이 좌우된다 특히 이동국들사이의 직교성 부재로 순방향 링크보다는 역방향 링크에서 간섭의 영향이 커진다. 따라서 본 논문에서는 역방향 링크에서 성능열화의 주 원인인 사용자간 간섭을 각 채널간 수신 동기를 확보하여 직교성을 유지함으로써 역방향 링크 성능을 향상시키는 방안을 제시하며, 역방향 링크 동기가 성립되지 않은 경우와 비교분석 하였다. 또한 본 논문에서는 역방향 동기 기법에서 간과하기 쉬운 핸드오버 영역에 존재하는 이동국(Mobile Station; MS)들까지를 고려하여 성능을 재 분석하였다. 즉 특정 이동국이 원천 기지국(Serving Base Station, Serving BS)에서 대상 기지국(Target Base Station; Target BS)으로 핸드오버 중이라고 가정할 때, 이 이동국은 원천 기지국(Serving BS)에 역방향 동기를 유지하고 있는 상태이므로 대상 기지국(Target BS)과는 역방향 동기가 성립되지 않는다. 이에 본 논문에서는 핸드오버 영역 이동국들의 영향을 고려하여 역방향 동기 기법을 재 고찰하였으며, 역방향 동기 기법을 적용하는데 있어서의 핸드오버의 영향을 시뮬레이션을 통해 정량적으로 제시하였다. 마지막으로 핸드오버 영역 이동국들로부터의 간섭으로 인해 역방향 링크 전체 용량이 감소됨에 대한 해결책의 하나로 최근 구현 고려 대상인 간섭 제거방식을 부분적으로 도입하는 방안을 제시하였으며, 성능을 시뮬레이션을 통해 제시하고 검토하였다. It is known that the performance of a DS-CDMA system mainly depends on Multiple Access Interference(MAI). The effect of MAI in a reverse link is larger than that of a forward link because of the absence of orthogonality among mobile stations. In this paper we investigate the effect of synchronous transmission in the reverse link, which is compared to the performance of asynchronous transmission in the reverse link. In addition, we consider the effect of interference from Mobile Stations(MSs) in a hand-over region. That is, if we assume that a MS is moving from a serving base station(sowing BS) to a target base station(target BS), the signal of the MS is not orthogonal with the signals of all other MSs within the target BS because the MS is only synchronized with the serving BS. Finally we suggest an interference cancellation scheme to reduce the interference from MSs in the region of hand-over, which can be one of solutions for the capacity degradation due to interference from the MSs in the hand-over region in reverse link synchronous transmission.
안병철 대한약침학회 2000 Journal of pharmacopuncture Vol.3 No.1
The purpose of this study is to prove the analgesic effects of apitoxin and its mechanism via jaw-opening reflex(JOR) and measuring expression of mRNA in Phospholipase and Tryptophan hydroxylase(TPH) using RT-PCR. The experiments were carried out on Sprague-Dawley rats(300-400g) and mastocytoma(P-185 HTR) for JOR and RT-PCR, respectively. Rats anesthetized with thiopental sodium (80mg/kg) were used in the Tooth Pulp stimulation induced JOR. The amplitude of a digastric electromyogram (dEMG) was recorded during the stimulation at an intensity of 1.5 times the threshold for JOR. Apitoxin used in this experiment was diluted with normal saline by 1:1000. Apitoxin was injected intravenously into the test group while normal saline to the control group. However, it was injected directly into the cell of mastocytoma. We referred to base sequence registered in Genbank in designing primers for RT-PCR. The results were as follows; (1)Compared with control group, analgesic effect started to show right after Sprague-Dawely rats were treated with apitoxin(71.50±8.08) and lasted for 50 minutes. (2)As a result of the experiment of RT-PCR, we witnessed significant changes in the degree of expression of phospholipase or rate-limiting enzyme of biosynthesis of prostaglandins with 10μg/ml apitoxin.(31.74±18.98%, P<0.05) (3)As a result of the experiment of RT-PCR, we witnessed significant changes in the degree of expression of TPH or rate-limiting enzyme in biosynthesis of serotonin with 10μg/ml apitoxin.(131.37±16.87%, P<0.05). These results suggest that 10μg/ml apitoxin have the most analgesic effects. This study showed that apitoxin has analgesic effects and held good for 50 minutes. The injection of apitoxin has brought out changes in the degree of expression of phospholipase and TPH. These results strongly suggest that analgesic mechanism by apitoxin is closely related to prostaglandins and serotonin.