• Journal of Communications and Networks
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• v.6 no.1
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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.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.117-120
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• 1999

Input queueing is useful for high bandwidth switches and routers because of lower complexity and fewer circuits than output queueing. The input queueing switch, however, suffers HOL-Blocking, which limits the throughput to 58%. To get around this low throughput, we propose a simple scheduling algorithm called Synchronous Input Port (SIP). This method synchronize packets and switching without blocking, which is shown to have better performance over the established algorithms

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.4
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• pp.10-19
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• 1998

With the advent of high-speed networks, the increasingly stringent performance requeirements are being placed on the underlying switching systems. Under these circumstances, simulation methods for evaluating the performace of such a switch requires vast computational cost and accordingly the importance of anlytical methods increases. In general, the performance analysis of a switch architecture is also a very difficult task in that the conventional queueing system such as switching systems, which consists of a large numbe of queues which interact with each other in a fiarly complicated manner. To overcome these difficulties, most of the past research results assumed that multiple queues become decoupled as the switch size grows unboundely large, which enables the conventional queueing theory to be applied. In this apepr, w analyze a non-blocking space-division ATM swtich with input queueing, and prove analytically the pheonomenon that virtual queues formed by the head-of-line cells become decoupled as the switch size grows unboundedly large. We also establish various properties of the limiting queue size processes so obtained and compute the maximum throughput associated with ATM switches with input queueing.

• Communications for Statistical Applications and Methods
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• v.9 no.3
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• pp.649-663
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• 2002

We consider an unlimited fluid queueing model which has Fractional Brownian motion(FBM) as an input and a single server of constant service rate. By using the result of Duffield and O'Connell(6), we investigate the asymptotic tail-distribution of the stationary work-load. When there are multiple homogeneous FBM inputs, the workload distribution is similar to that of the queue with one FBM input; whereas for the heterogeneous sources the asymptotic work-load distributions is dominated by the source with the largest Hurst parameter.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.12
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• pp.58-66
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• 2001

Input queueing is useful for high bandwidth switches and routers because of lower complexity and fewer circuits than output queueing. The input queueing switch, however, suffers HOL-Blocking, which limits the throughput to 58%. To get around this low throughput, many input queueing switches have centralized scheduler, which centralized scheduler restrict the design of the switch architecture. To overcome this problem, we propose a simple scheduler called PRR(Pipelined Round Robin), which is intrinsically distributed and presents to show the effectiveness of the proposed scheduling.

• ETRI Journal
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• v.22 no.3
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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.

• Proceedings of the Korean Statistical Society Conference
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• 2003.10a
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• pp.1-8
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• 2003

The traffic patterns of today's IP networks exhibit two important properties: self-similarity and long-range dependence. The fractional Brownian motion is widely used for representing the traffic model with the properties. We consider a single server fluid queueing system with input process of a fractional Brownian motion type. Formulas for effective bandwidth are derived in a single source and multiple source cases.

• Journal of Electrical Engineering and information Science
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• v.2 no.6
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• pp.56-63
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• 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.

• Proceedings of the Korean Society for Quality Management Conference
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• 2007.04a
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• pp.461-465
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• 2007

The BMAP/M/N/O queueing system operating in Markovian random environment is investigated. The stationary distribution of the system is calculated. Loss probability and other performance measures are calculated. Numerical experiments which show the necessity of taking into account the influence of random environment and correlation in input flow are presented.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.271-275
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• 2005

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.