Syntheses of Aminocyclopentadienyl Ruthenium complexes and Ru-carboxylate complexes and Study on Their Catalytic Activities for Racemization of Secondary Alcohols

Maste

스타 구조를 갖는 근거리 통신망에서 사용되는 충돌 없는 프로토콜의 성능 분석에 관한 연구

학위논문(박사) - 한국과학기술원 : 전기 및 전자공학과, 1991.8, [ xi, 150 p. ]The main objective of this dessertation is to investigate the performance characteristics of a broadcast star network with collision avoidance switch and a multichannel local lightwave network with grouping property. So far, quite a few attempts have been made to model the broadcast star network with collison avoidance switch. Most of those models assumed constant message length and random selection policy at the central hub. If the central hub can choose the oldest message among the messages which are transmitted at the same slot, tnen the service discipline becomes first-come first-served (FCFS). Although the FCFS didcipline has many desirable featrues such as fairness and lowest variance of message delay, this discipline is not easy to implement since the central hub does not know the arrival times of messages. If the central hub chooses one message randomly among the messages which are transmitted at the same slot, then the service discripline becomes random-order of service(ROS). While the ros discipline is easy to implement, the message delay is not bounded and the variance of message delay becomes large in this descipline. For this reason, we first proposed a service disciplin which is relatively easy to implement and which has the variance characteristics of message delay almost the same as the FCFS case (ideal case). the proposed service discipline is combination of FCFS and ROS disciplines and it uses reservation and priority fields in the message header. Using the proposed seervice discipline, we presented models for a broadcast star network with collision avoidance switch separately in two casesi a broadcast star network with small propagation delay and a broadcast star network with large propagation delay. We assumed that the network consists of an infinite population of stations which collectively generate new messages according to a Poisson distribution and that the size of each message is distributed according to a general distribution. We also ...한국과학기술원 : 전기 및 전자공학과

A study on voice/data integration in token ring lan

학위논문(석사) - 한국과학기술원 : 전기 및 전자공학과, 1987.2, [ vi, 62 p. ]본 논문에서는 token ring LAN에 voice와 data를 integration하기 위한 hardware와 software의 구조를 제시하였고,성능분석을 통하여 여러 system parameter들을 변화시킬 때, 그것이 voice와 data packet의 delay에 미치는 영향에 대하여 연구하였다. 먼저 hardware의 구조로 data만 service하는 LAN의 IOM board를 변형하여 두 가지 type의 traffic을 같이 처리함으로 큰 overhead없이 VDI를 실현할 수 있음을 보였으며, 이를 위한 software의 구조로 data의 service를 위한 PAD program과 독립적으로 동작하며, 전화통화를 위한 기본적 service들을 해 주는 voice protocol을 제안하였다. 성능 분석에서는 token ring LAN을 cyclic service를 받는 multiqueue system으로 modelling하여 conditional cycle time의 개념을 사용하여 해석하였다. 결과적으로 voice packet과 data packet의 mean delay time 은 conditional cycle time들의 first와 second moment의 함수로 주어짐을 알 수 있었다. 그리고 token ring LAN은 voice / data integration에 매우 적합한 근거리 통신망임을 알 수 있었다.한국과학기술원 : 전기 및 전자공학과