• 산업경영시스템학회지
• /
• 제32권4호
• /
• pp.161-168
• /
• 2009

The most generalized form of the triadic operating policy for an M/G/1 queueing model is developed. It consists of three simple N, T and D operating policies and has a peculiar structure possessing concepts of dyadic policies. Using the concept of the pseudo probability density function of the busy period, its expected busy period for the controllable M/G/1 queueing model is derived. Since the obtained result is the most generalized form the triadic polity, the expected busy periods for all known dyadic policies are recovered as special cases from it.

• 전기학회논문지
• /
• 제58권10호
• /
• pp.1911-1915
• /
• 2009

The problem of determining the proper capacity of electric vehicle charging station is studied in the presented paper. Based on the expected arrival rate and the expected charging time, we calculate the proper capacity that guarantees electric vehicles get service better than a given lower bound which is termed the loss of charging probability. The problem is studied by using certain queueing models. We first formulate the problem as a queueless model of type M/M/n/n, known as the Erlang loss system. And then the M/M/n/K type queueing model is formulated to consider the parking space constraint. Results of the study may be used for designing the electric vehicle charging station.

• Journal of Communications and Networks
• /
• 제4권3호
• /
• pp.209-220
• /
• 2002

In this paper, we propose a hierarchical packet scheduling technique to closely approximate a hierarchical extension of the generalized processor sharing model, Hierarchical Generalized Processor Sharing (H-GPS). Our approach is to undertake the tasks of service guarantee and hierarchical link sharing in an independent manner so that each task best serves its own objective. The H-GPS model is decomposed into two separate service components: the guaranteed service component to consistently provide performance guarantees over the entire system, and the excess service component to fairly distribute spare bandwidth according to the hierarchical scheduling rule. For tight and harmonized integration of the two service components into a single packet scheduling algorithm, we introduce two novel concepts of distributed virtual time and service credit, and develop a packet version of H-GPS called Hierarchical Fair Queueing (HFQ). We demonstrate the layerindependent performance of the HFQ algorithm through simulation results.

• 한국국방경영분석학회지
• /
• 제6권2호
• /
• pp.47-67
• /
• 1980

Interactions of major activities participating in fleet operations are investigated in the framework of a closed queueing network system with finite aircrafts assigned to it. An implementable algorithm is developed, which is useful for computing the distributions needed to evaluate the effects of the interactions on the fleet operations. The availability management program is focused on seeking an optimal resource allocation to multiple repair-shops to maximize the fleet availability subject to the budget constraint.

• 한국경영과학회지
• /
• 제19권3호
• /
• pp.235-241
• /
• 1994

We consider a B/G/1 queueing with vacations, where the server closes the gate when it begins a vacation. In this system, customers arrive according to a Bernoulli process. The service time and the vacation time follow discrete distributions. We obtain the distribution of the number of customers at a random point in time, and in turn, the distribution of the residence time (queueing time + service time) for a customer. It is observed that solutions for our discret time B/G/1 gated vacation model are analogous to those for the continuous time M/G/1 gated vacation model.

• 한국시뮬레이션학회:학술대회논문집
• /
• 한국시뮬레이션학회 2001년도 The Seoul International Simulation Conference
• /
• pp.359-364
• /
• 2001

In this study, we try to improve the accuracy of QN-GPH by the help of simulation approach. We first establish an estimation method for GPH distributions with sufficient accuracy based on empirical distribution, and then perform a brief trial run to find appropriate empirical distributions. After getting GPH form of distributions, we continue the QN-GPH analytic steps and compute necessary performance measures. We apply the method to find sojourn time distributions in a 8-node queueing system and compare the results with the whole simulation and the original two-parametric approximation.

• 한국경영과학회지
• /
• 제21권2호
• /
• pp.203-213
• /
• 1996

A system is considered which is required to perform tasks that arrive randomly during a fixed mission duration. We develop queueing models to obtain the mission effectiveness and the blocking probabilities. Exact probabilities are computed by using the Finite Fourier Cosine Transform.

• Journal of Electrical Engineering and information Science
• /
• 제2권6호
• /
• pp.56-63
• /
• 1997

Under most system assumptions, closed form solutions of performance measures for ATM switches with input queueing are not available. In this paper, we present expressions and bounds for the derivatives of cell loss probabilities with respect to the arrival rate evaluated at a zero arrival rate. These bounds are used to give an approximation by Taylor expansion, thereby providing an economical way to estimate cell loss probabilities in light traffic.

• 산업경영시스템학회지
• /
• 제28권1호
• /
• pp.114-120
• /
• 2005

This paper studies procedures for bottleneck detection in closed queueing networks(CQN's) with multiple job classes. Bottlenecks refer to servers operating at $100\%$ utilization. For CQN's, this can occur as the population sizes approach infinity. Bottleneck detection reduces to a non-linear complementary problem which in important special cases may be interpreted as a Kuhn-Tucker set. Efficient computational procedures are provided.

• 전자공학회논문지CI
• /
• 제38권4호
• /
• pp.1-9
• /
• 2001

본 논문에서는 한 개의 서버와 시스템용량 K를 갖는 M/M/1/K 큐잉네트워크모델에 펴지집합이론을 적용한 퍼지 M/M/1/K 큐잉네트워크모델을 제안하였다. 작업의 도착율과 서버의 서비스율의 형태가 언어적 속성으로 표현될 때， 이 모델을 사용하여 시스템의 해석이 가능해진다. 시스템의 평가를 위해서 시스템내 평균작업수， 작업 평균진입률， 그리고 작업 평균소요시간 등 시스템의 주요 평가측도를 유도하였다. 퍼지 작업 환경에서 이러한 결과식들의 유효함을 검증하기 위하여， 제안된 모델에 다양한 퍼지도착율 ${\lambda}$와 퍼지서비스율 ${\mu}$에 대하여 시스템용량 K 값의 변화에 따른 성능평가를 컴퓨터 시뮬레이션하였다. 그 결과가 제안한 퍼지 모델에서 예측한 평가와 일치함을 확인하였다.