• International Journal of Reliability and Applications
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• v.3 no.4
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• pp.165-171
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• 2002

An optimization of the M/M/1 queue with impatient customers is studied. The impatient customer does not enter the system if his or her virtual waiting time exceeds the threshold K ＞ 0. After assigning three costs to the system, a cost proportional to the virtual waiting time, a penalty to each impatient customer, and also a penalty to each unit of the idle period of the server, we show that there exists a threshold K which minimizes the long-run average cost per unit time.

• Communications for Statistical Applications and Methods
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• v.7 no.2
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• pp.489-497
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• 2000

The M/M/1 queue with impatient customers is studied. Impatient customers wait for service only for limited time K/0 and leave the system if their services do not start during that time. Notice that in the analysis of virtual waiting time, the impatient customer can be considered as the customer who enters the system only when his/her waiting time does not exceed K. In this paper, we apply martingale methods to the virtual waiting time and obtain the expected period from origin to the point where the virtual waiting time crosses over K or reaches 0, and the variance of this period. With this results, we obtain the expected busy period of the queue, the distribution, expectation and variance of the number of times the virtual waiting time exceeding level K during a busy period, and the probability of there being no impatient customers in a busy period.

• Proceedings of the Korean Statistical Society Conference
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• 2004.11a
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• pp.289-294
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• 2004

We consider M/G/1 queue in which the customers are classified into n+1 classes by their impatience time. First, we analyze the model of two types of customers; one is the customer with constant impatience duration k and the other is patient customer. The expected busy period of the server and the limiting distribution of the virtual waiting time process are obtained. Then, the model is generalized to the one in which there are classes of customers according to their impatience duration.

• Journal of Korean Institute of Industrial Engineers
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• v.27 no.1
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• pp.89-94
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• 2001

There are many queueing systems where customers wait for service up to a certain amount of time and leave the system if they are not served during that time. This paper considers a finite capacity multi-server queueing system with Poisson input and Erlang service time, where a customer becomes a lost customer when his service has not begun within an exponential patient time after his arrival. Performance measures such as average queue length, the average number of customers in service, and the proportion of lost customers can be obtained exactly through the proposed numerical solution procedure.

• Journal of the Korean Society of Clothing and Textiles
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• v.32 no.3
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• pp.362-372
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• 2008

The remarkable tendency shown in recent fashion can be the customer's passiveness, not only their feeling desire for product but also needs for product seem to be made by mass media. So this condition can be thought as the currency of energy for being subjected. The public of fashion eagerly want the fashion style to be suggested for following it. The late Freudian, Erich Fromm said that the reason why individuals demand themselves to follow the masses' move could be explained as the hope against the fear of feeling not being from staying isolated and having no direction. Escaping from this fear, individuals ought to believe the necessity of participation in public. The fashion is willing to be defined as the united condition by individuals in the hope being consolidate in masses against being solitude. Nowadays, people can share many informations with internet, the fastest medium, which makes the individuals impatient not to be isolate, thinking other people must contact the information and should feel pressure of taking part in the currency. Even though the style is considered to be awkward for following it, it's frequent exposure on mass media by celebrities wearing the style could soon make a fashion. This is able to show that many customers should incline to consider less about their style or taste, whereas lean to pursue after masses' authority. Recent consumers have propensity to avoid feeling concern about others' criticism, on the other side, they try to chase of the fashion as masses' choice for feeling peaceful. The reason why people recognize not to have clothing to wear in spite of a large wardrobe, it must reflect their needs promoted from outside influence of introducing for new styles.