• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.1137-1140
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• 2005

We present the discrete-time version of the heuristic interpretation of the mean waiting time known well about the continuous-time version. The heuristic approach is mainly based on an arriving customer's viewpoint. We obtain the mean waiting time of $Geo^X/G/1$ queueing systems, including vacation queues.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.874-880
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• 2005

본 논문에서는 D-정책과 복수휴가를 갖는 MAP/G/1 대기행렬시스템의 고객수를 분석한다. 고객도착은 마코비안 도착과정(MAP)을 따른다. 서어버는 바쁜기간 종료 직후 휴가를 떠나고 휴가에서 돌아온 직후의 시스템 총일량이 D를 초과할 때까지 휴가를 반복한다. 만일, 휴가에서 돌아온 직후의 시스템 총일량이 D를 초과하면, 서어버는 즉시 서비스를 시작한다. 본 논문에서는 임의의 이탈시점 고객수분포를 유도하고, 이를 이용하여 임의시점 고객수분포와 평균고객수를 유도한다. 또한, 동일한 조건하에 D-정책과 복수휴가를 갖는 M/G/1 대기행렬시스템의 평균고객수와의 차이를 비교해 본다.

• Journal of the Korean Operations Research and Management Science Society
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• v.29 no.3
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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.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.05a
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• pp.1104-1110
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• 2006

In this paper we present a simple approach to the joint queue length distribution in the nonpreemptive priority M/G/1 queue. Without using the supplementary variable technique, we derive the joint probability generating function of the stationary queue length at arbitrary time.

• Journal of the Korean Operations Research and Management Science Society
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• v.33 no.1
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• pp.107-115
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• 2008

We consider the discrete-time GI/G/1/K queue under the early arrival system. Using a modified supplementary variable technique(SVT), we obtain the distribution of the steady-state queue length. Unlike the conventional SVT, the modified SVT yields transform-free results in such a form that a simple two-moment approximation scheme can be easily established.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.05a
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• pp.1111-1115
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• 2006

We present heuristic interpretations of the mean waiting time of $Geo^X/G/1$ vacation queues with set-up time. The heuristic interpretation of the mean waiting time is originally proposed for the continuous-time queues. We demonstrate that the heuristic approach is useful for the discrete-time queues as well.

• Journal of the Korean Operations Research and Management Science Society
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• v.17 no.2
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• pp.123-130
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• 1992

The model of k-out-of n : G repairable system with identical components is extended to a repairable system with n different components. The objective is to analytically derive the mean time of the busy period for a k-out-of-n : G system with unrestricted repair. Then, the lower and upper bounds on the average time of the busy period of the n-component system with restricted repair are also shown.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.560-565
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• 2005

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1999.04a
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• pp.399-399
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• 1999

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.12C
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• pp.233-239
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• 2001

Among the operations in frequency domain for ADSL G.LITE Modem to perform, FFT and FEQ are most computation-intensive part, of which many researches have been focused on the efficient implementation. Previous papers suggested hardwares suitable for ADSL G.DMT system, which is not feasible for simple G.LITE system. The analysis of frequency domain operations and computational efficiency according to the allocation of hardware resources is performed in this paper. The suggested processor has the structure of one real multiplier and two real adders connected in parallel, which can perform the operations efficiently through the pipeline- and/or parallel-type job scheduling. The suggested processor uses less hardware resources than Kiss\`s ALU structure or FFT/IFFT processor suggested by Wang, so the suggested one is more suitable for G.LITE system than previous works.