• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1996년도 춘계공동학술대회논문집; 공군사관학교, 청주; 26-27 Apr. 1996
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• pp.543-546
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• 1996

Recently, some research has been done to analyze the asymptotic behavior of queue length distribution in ATM (Asynchronous Transfer Mode) multiplexer. In this paper, we relate this asymptotic behavior with the asymptotic behavior of decreasing cell loss probability when the buffer capacity is increased. We find with reasonable assumptions that the asymptotic rate of queue length distribution is the same as that of decreasing cell loss probability. Even under different priority control schemes and traffic classes, we find that this asymptotic rate of the individual cell loss probability of each traffic class does not change. As a consequence, we propose the upper bound of cell loss probability of each traffic class when a priority control scheme is employed. This bound is computationally feasible in a real-time. The numerical examples will be provided to validate this finding.

• 대한수학회논문집
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• 제8권1호
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• pp.77-95
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• 1993

• 대한전자공학회논문지TC
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• 제42권2호
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• pp.23-38
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• 2005

무선 네트워크에서는 여러 가지의 환경적 요인으로 인해 발생하는 페이딩 현상 및 노이즈로 인하여 무선 단말기 간의 채널의 상태가 자주 변화한다. 따라서 시변 채널 특성을 지니는 무선 네트워크에서 신뢰성 있는 데이터 전송을 위해서는 시변 채널 특성을 파악하는 것이 중요하다. 본 논문에서는 무선 네트워크 시변(Time-varying) 채널 상에서 패킷 전송 시간 및 대기큐에 대해 분석한다. 무선 네트워크 시변 채널 상태를 반영하기 위해 채널의 상태를 2-상태, 3-상태 각각의 경우로 구분하고 SFG(Signal Flow Graph) 모델을 이용하여 채널 상태를 해석한다. 각각의 상태에 대한 SFG 모델로부터 하나의 패킷에 대해 평균 전송시간과 분산을 구하고 이에 대한 확률 분포를 가우시안(Gaussian) 분포로 생각한다. 패킷의 도착분포가 프아송(Poisson) 프로세스를 따르는 전송 시스템을 M/G/1으로 모델링하고 에러 정정 기법으로 SW ARQ 기법을 적용하여 패킷의 PER의 변화 및 패킷 도착 비율의 변화에 따른 평균 패킷 전송시간과 평균 대기큐의 길이에 대해 해석하고 시뮬레이션을 통하여 검증한다.

• 공학논문집
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• 제3권1호
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• pp.85-95
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• 1998

본 논문에서 blocking이 발생되고 다중 customer를 취급하는 유한용량의 Coxian 대기 네트워크를 분석하기 위한 회귀적인 방법을 연구한다. 다중 customer를 나타내기 위한 대용량의 state space로 인해 발생되는 메모리 문제와 rate matrix의 부행렬들에 대한 inverse를 구할 수 없는 관계로 발생될 수 있는 singular 문제를 해결하는 방법을 제안한다. 2가지 blocking 방식(FBFE, HPFE)에 대한 분석을 Gauss-Seidel 방법과 비교하여 본다.

• 한국경영과학회지
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• 제29권3호
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• pp.1-7
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• 2004

We demonstrate in this paper that the level crossing technique can be applied to such a system that not only the state vector is two-dimensional but Its two components are heterogeneous. As an example system, we use the GI-G/c/K queue whose state vector consists of the number of customers in the system and the total unfinished work.

• 한국경영과학회지
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• 제26권4호
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• pp.39-45
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• 2001

Maximum and minimum of rendom variables are frequently encountered in the stochastic modelling for various OR problems. We summarize and extend characteristics of maximum and minimum, emphasizing the case in which random variables are independent and all of them except one are distributed exponential. As an application, we derive a transform-free expression for the M/G/1 queue length distribution.

• 산업경영시스템학회지
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• 제40권3호
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• pp.66-75
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• 2017

Priority disciplines are an important scheme for service systems to differentiate their services for different classes of customers. (N, n)-preemptive priority disciplines enable system engineers to fine-tune the performances of different classes of customers arriving to the system. Due to this virtue of controllability, (N, n)-preemptive priority queueing models can be applied to various types of systems in which the service performances of different classes of customers need to be adjusted for a complex objective. In this paper, we extend the existing (N, n)-preemptive resume and (N, n)-preemptive repeat-identical priority queueing models to the (N, n)-preemptive repeat-different priority queueing model. We derive the queue-length distributions in the M/G/1 queueing model with two classes of customers, under the (N, n)-preemptive repeat-different priority discipline. In order to derive the queue-length distributions, we employ an analysis of the effective service time of a low-priority customer, a delay cycle analysis, and a joint transformation method. We then derive the first and second moments of the queue lengths of high- and low-priority customers. We also present a numerical example for the first and second moments of the queue length of high- and low-priority customers. Through doing this, we show that, under the (N, n)-preemptive repeat-different priority discipline, the first and second moments of customers with high priority are bounded by some upper bounds, regardless of the service characteristics of customers with low priority. This property may help system engineers design such service systems that guarantee the mean and variance of delay for primary users under a certain bounds, when preempted services have to be restarted with another service time resampled from the same service time distribution.

• 대한산업공학회지
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• 제14권2호
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• pp.1-10
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• 1988

We consider a vacation system in which the server takes two different types of vacations alternately. We obtain the server idle probability and derive the system size distribution and the waiting time distribution by defining supplementary variables. We show that the decomposition property works for these mixed-vacation queues. We also propose a method directly to obtain the waiting time distribution without resorting to the system equations. The T-policy is revisited and is shown that the cost is minimized when the length of vacations are the same.

• Korean Journal of Mathematics
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• 제11권1호
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• pp.35-43
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• 2003

We study the weak convergence to Fractional Brownian motion and some examples with applications to traffic modeling. Finally, we get loss probability for queue-length distribution related to self-similar process.

• 한국통신학회:학술대회논문집
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• 한국통신학회 2004년도 하계종합학술발표회논문초록집
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• pp.293-293
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• 2004