• Industrial Engineering and Management Systems
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• 제7권2호
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• pp.143-149
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• 2008

There have been some approximation analysis methods for a GI/G/1 queueing system. As one of them, an approximation technique for the steady-state probability in the GI/G/1 queueing system based on the iteration numerical calculation has been proposed. As another one, an approximation formula of the average queue length in the GI/G/1 queueing system by using the diffusion approximation or the heuristics extended diffusion approximation has been developed. In this article, an approximation technique in order to analyze the GI/G/1 queueing system is considered and then the formulae of both the steady-state probability and the average queue length in the GI/G/1 queueing system are proposed. Through some numerical examples by the proposed technique, the existing approximation methods, and the Monte Carlo simulation, the effectiveness of the proposed approximation technique is verified.

• 한국경영과학회지
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• 제33권1호
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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.

• 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.

• Journal of applied mathematics & informatics
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• 제28권1_2호
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• pp.153-162
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• 2010

The finite buffer GI/G/1/K system is set up by using an unconventional arrangement of the state space, in which the remaining interarrival time or service time is chosen as the level. The stationary distributions of resulting Markov chain can be explicitly determined, and the chain is positive recurrent without any restriction. This is an advantage of this method, compared with that using the elapsed time approach [2].

• Journal of applied mathematics & informatics
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• 제31권1_2호
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• pp.311-325
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• 2013

The effects of the moments of the interarrival time and service time on the system performance measures such as blocking probability, mean and standard deviation of the number of customers in service facility and orbit are numerically investigated. The results reveal the performance measures are more sensitive with respect to the interarrival time than the service time. Approximation for $GI/G/c$ retrial queues using $PH/PH/c$ retrial queue is presented.

• 대한산업공학회지
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• 제42권5호
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• pp.304-313
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• 2016

This work suggests a new analysis approach for a discrete-time GI/G/1 queue with multiple vacations. The method used is called a modified supplementary variable technique and our result is an exact transform-free expression for the steady state queue length distribution. Utilizing this result, we propose a simple two-moment approximation for the queue length distribution. From this, approximations for the mean queue length and the probabilities of the number of customers in the system are also obtained. To evaluate the approximations, we conduct numerical experiments which show that our approximations are remarkably simple yet provide fairly good performance, especially for a Bernoulli arrival process.

• Journal of Pharmaceutical Investigation
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• 제36권4호
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• pp.263-269
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• 2006

Deficiencies in the early ADMET(absorption, distribution, metabolism, elimination and toxicity) information on drug candidate extract a significant economic penalty on pharmaceutical firms. Microscale cell culture analogue-microscale gastrointestinal(${\mu}CCA-{\mu}GI$) device using Caco 2, L2 and HEp G2/C3A cells, which mimic metabolic process after absorption occurring in humans was used to investigate the toxicity of the model chemical, acetaminophen(AAP). The toxicity of acetaminophen determined after induction of CYP 1A1/2 in Caco 2 cells was not significant. In a coculture system, although no significant reduction in viability of HEp G2/C3A and L2 cells was found, approximately 5 fold increase in the CYP 1A1/2 activity was observed. These results appear to be related to organ-organ interaction. The oral administration of a drug requires addition of the absorption process through small intestine to the current ${\mu}CCA$ device. Therefore, a perfusion coculture system was employed for the evaluation of the absolution across the small intestine and resulting toxicity in the liver and lung. This system give comprehensive and physiologic information on oral uptake and resulting toxicity as in the body. The current ${\mu}CCA$ device can be used to demonstrate the toxic effect due to organ to organ interaction after oral administration,

• 한국경영과학회:학술대회논문집
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• 한국경영과학회/대한산업공학회 2003년도 춘계공동학술대회
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• pp.247-251
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• 2003

In this paper, we propose an approximation of the M/G/1 system with finite workload capacity, where customers whose admission to the system would increase the workload beyond a prespecified finite capacity limit are not accepted. Our approximation method is based on the idea that the service time of a customer in the M/G/1 system can be approximated as the sum of service times of a batch of customers in the $M^{X}/d/1$ system where the service time is deterministic and very small. That is, the original service time is discretized and approximated by the batch size. We exemplified our method by obtaining the average workload of the M/M/1 system by means of the $M^{X}/d/1$ system, where the batch size is geometric. In addition, the approximate blocking probabilities of the M/M/1 and $M/E_{k}/1$ system with finite workload capacities are sought. The proposed method turns out to give a good approximation, which is compared with a simulation.

• Genomics & Informatics
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• 제16권1호
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• pp.2-9
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• 2018

Olfactory receptors (ORs) in mammals are generally considered to function as chemosensors in the olfactory organs of animals. They are membrane proteins that traverse the cytoplasmic membrane seven times and work generally by coupling to heterotrimeric G protein. The OR is a G protein-coupled receptor that binds the guanine nucleotide-binding $G{\alpha}_{olf}$ subunit and the $G{\beta}{\gamma}$ dimer to recognize a wide spectrum of organic compounds in accordance with its cognate ligand. Mammalian ORs were originally identified from the olfactory epithelium of rat. However, it has been recently reported that the expression of ORs is not limited to the olfactory organ. In recent decades, they have been found to be expressed in diverse organs or tissues and even tumors in mammals. In this review, the expression and expected function of olfactory receptors that exist throughout an organism's system are discussed.

• Journal of Ginseng Research
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• 제33권3호
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• pp.229-233
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• 2009

홍삼농축액분말을 발효주정을 이용하여 과립입자를 제조한 후 이것을 원심력에 의해 부유시키고 성장시켜 100% 홍삼농축액 환을 제조하는 새로운 원심분리 코팅방법을 개발하였다. 본 방법은 홍삼농축액을 순차적으로 분무하면서 흡입공기 온도 60$\sim$70$^{\circ}C$, 분무공기 압력 3.0$\sim$4.0 bar, 투입구 온도 20$\sim$50$^{\circ}C$, 투입속도 1$\sim$1,000 g/min, 회전판속도 1,000$\sim$1,500 rpm, 외부온도 (outlet temperature) 25$\sim$40$^{\circ}C$의 조건으로 제조하였다. 홍삼농축액환의 제조수율은 85% 이었고, 제조에 소요된 시간은 7$\sim$8 시간 이었다. 홍삼농축액환은 홍삼농축액분말에 비해 흡습성 내성이 매우 우수하였고, 비중감소에 의해 물에서의 용해시간도 1 분 이내로 우수하였다. 반면 홍삼의 활성 및 지표성분인 진세노사이드는 제조과정 중 큰 성분 분해없이 안정하였다.