• 한국산업정보학회논문지
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• 제11권1호
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• pp.1-6
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• 2006

Queueing models are good models for fragments of communication systems and networks, so their investigation is interesting for theory and applications. Theses queues may play an important role for the validation of different decomposition algorithms designed for investigating more general queueing networks. So, in this paper we illustrate that the batch size distribution affects the loss probability, which is the main performance measure of a finite buffer queues.

• 한국시뮬레이션학회논문지
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• 제7권2호
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• pp.63-78
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• 1998

The hierarchical cell structure consists of the macrocell and microcells to increase the system capacity and to achieve broad coverage. The hierarchical cell structure provides services for users in different mobility. In this paper, an analytical queueing model in mobile networks is proposed for the performance evaluation of the hierarchical cell structure. The model for networks with the multiple levels can simplify multi-dimensional ones into one-dimensional queueing model. The computational advantage will be growing as the layers are constructed in multiple levels. The computer simulation is provided for validating the proposed analytical model.

• 경영과학
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• 제4권
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• pp.60-75
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• 1987

This paper introduces the outlines of the state-of-the-art in studying FMSs using analytical queueing network models. These include Jackson networks, reversible networks and approximate models of non-product-form networks. the focus is on identifying the major features of models as they relate to the operational characteristics of FMSs. Prescriptive models concerning the optimal design and/or operational control of FMS networks are also discussed. We notice that the presentation of materials in this paper basically follows Yao and Buzacott, On Queueing Network Models of Flexible Manufacturing Systems(FMSs), invited and published on Queueing Systems, Theory and Application 1(1986). For other analytical models of FMSs, refer to Buzacott and Yao, Flexible Manufacturing Systems : A Review of Analytical Models, Management Science 32, No.7(1986).

• Journal of Communications and Networks
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• 제6권1호
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• pp.78-87
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• 2004

This paper presents deterministic, worst-case analysis of a queueing system whose multiple homogeneous input streams are regulated by the associated leaky buckets and the queueing system that has a single stream regulated by the jumping-window. Queueing delay averaged over all items is used for performance measure, and the worst-case input traffic and the worst-case performance are identified for both queueing systems. For the former queueing system, the analysis explores different phase relations among leaky-bucket token generations. This paper observes how the phase differences among the leaky buckets affect the worst-case queueing performance. Then, this paper relates the worst-case performance of the former queueing system with that of the latter (the single stream case, as in the aggregate streams from many users, whose item arrivals are regulated by one jumping-window). It is shown that the worst-case performance of the latter is identical to that of the former in which all leaky buckets have the same phase and have particular leaky bucket parameters.

• ETRI Journal
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• 제22권3호
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• pp.1-9
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• 2000

Self-Clocked Fair Queueing (SCFQ) algorithm has been considered as an attractive packet scheduling algorithm because of its implementation simplicity, but it has unbounded delay property in some input traffic conditions. In this paper, we propose a Rate Proportional SCFQ (RP-SCFQ) algorithm which is a rate proportional version of SCFQ. If any fair queueing algorithm can be categorized into the rate proportional class and input is constrained by a leaky bucket, its delay is bounded and the same as that of Weighted Fair Queueing (WFQ) which is known as an optimal fair queueing algorithm. RP-SCFQ calculates the timestamps of packets arriving during the transmission of a packet using the current value of system potential updated at every packet departing instant and uses a starting potential when it updates the system potential. By doing so, RP-SCFQ can have the rate proportional property. RP-SCFQ is appropriate for high-speed packet-switched networks since its implementation complexity is low while it guarantees the bounded delay even in the worst-case input traffic conditions.

• 전자공학회논문지A
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• 제32A권4호
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• pp.15-23
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• 1995

In this paper, we evaluate the performance of a transient queueing approximation when it is applied to modeling computer communication networks. An operational computer network that uses the ISO IS-IS(Intermediate System-Intermediate System) routing protocol is modeled as a Jackson network. The primary goal of the approximation pursued in the study was to provide transient queue statistics comparable in accuracy to the results from conventional Monte Carlo simulations. A closure approximation of the M/M/1 queueing system was extended to the general Jackson network in order to obtain transient queue statistics. The performance of the approximation was compared to a discrete event simulation under nonstationary conditions. The transient results from the two simulations are compared on the basis of queue size and computer execution time. Under nonstationary conditions, the approximations for the mean and variance of the number of packets in the queue erer fairly close to the simulation values. The approximation offered substantial speed improvements over the discrete event simulation. The closure approximation provided a good alternative Monte Carlo simulation of the computer networks.

• 한국산업정보학회논문지
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• 제12권2호
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• pp.16-23
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• 2007

Tandem queueing systems well suit for modeling many telecommunication systems. Recently, very general $BMAP/G/1/N/1{\to}{\bullet}/PH/1/M-1$ type tandem queues were constructively studied. In this paper we illustrate application of the obtained results for optimization of a buffer pool design.

• 한국시뮬레이션학회논문지
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• 제20권2호
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• pp.1-10
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• 2011

본 연구에서는 대기행렬네트워크 성과측정 방법 중의 한 가지로서 널리 이용되는 분해법의 구성요소로 제안된 변동성 함수 의 이론적 근거를 살펴보고 성과척도 측정의 정확도 제고를 위하여 회귀분석을 통한 변동성 함수의 모수추정 개선방안을 제안하고자 한다. 이를 위하여 변동성이 높은 도착과정과 서비스 과정이 포함된 직렬 대기행렬 네트워크에서의 이탈과정의 자동상관계수 함수를 추정하여 분해법에 사용할 수 있는 방안을 알아본다.

• 한국정보통신학회논문지
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• 제7권6호
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• pp.1177-1186
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• 2003

멀티미디어 Ad Hoc 무선망은 이동하는 End User에게 멀티미디어 서비스를 제공할 수 있게 하는 유연한 해결방안을 제공하기 때문에 매력적인 주제이다. 그러나 Ad Hoc 무선망의 특별한 설계상의 문제점들로 인하여 자원을 공정하게 공유하면서 제한된 지연시간을 보장하는 것은 간단한 문제가 아니다. 이 논문에서는 지연시간보장 공정큐잉 (DGFQ, Delay Guaranteed Fair Queueing) 방식을 분산적으로 구현하였다. 성능평가를 통하여 DGFQ 방식이 멀티미디어 Ad Hoc 무선망에서도 제한된 지연시간을 제어할 수 있음을 보였다.

• Journal of applied mathematics & informatics
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• 제12권1_2호
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• pp.395-408
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• 2003

Common Channel Signaling(CCS) networks need special controls to avoid overload of signaling networks and degradation of call process-ing rate, since they play an important role of controlling communication transfer networks. Congestion control and flow control mechanisms are well described in ITU-T recommendation on Signaling System No.7(SS7). For the practical provisions, however, we need an analysis on the relation among service objects, system requirements and implementation of congestion control algorithms. SS7 provides several options for controlling link congestion in CCS networks. In this paper we give a general queueing model of congestion control algorithm which covers both the international and national options. From the queuing model, we obtain the performance parameters such as throughput, message loss rate and mean delay for the international option. To show the performance of the algorithm, some numerical results are also given.