• 한국경영과학회지
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• 제19권3호
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• pp.235-241
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• 1994

We consider a B/G/1 queueing with vacations, where the server closes the gate when it begins a vacation. In this system, customers arrive according to a Bernoulli process. The service time and the vacation time follow discrete distributions. We obtain the distribution of the number of customers at a random point in time, and in turn, the distribution of the residence time (queueing time + service time) for a customer. It is observed that solutions for our discret time B/G/1 gated vacation model are analogous to those for the continuous time M/G/1 gated vacation model.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1993년도 춘계공동학술대회 발표논문 및 초록집; 계명대학교, 대구; 30 Apr.-1 May 1993
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• pp.49-56
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• 1993

We consider a B/G/1 queueing system with vacations, where the server closes the gate when it begins a vacation. In this system, customers arrive according to a Bernoulli process. The service time and the vacation time follow discrete distributions. We obtain the distribution of the number of customers at a random point in time, and in turn, the distribution of the residence time (queueing time + service time) for a customer. This system finds an application in the performance evaluation of the DQDB protocol which has been adopted as the standard protocol for IEEE 802.6 MAN.

• 한국경영과학회지
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• 제19권2호
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• pp.45-56
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• 1994

This paper the profit maximizing order quantity model to the symmetric oligopoly consisting of sellers of a homogeneous product who compete with each other for the same potential buyers. Buyers are classified by type, each selecting an optimal purchase quantity in response to the nonlinear quantity discount pricing schedule given by the sellers. Symmetric equilibrium and the economic quantities that sellers must determine are analysed in a Cournot framework, which explicitly depend on the number of sellers. Economic implications are obtianed from the optimality conditions based on themarket share paraments which are used to characterize the competitior's marketing strategy.

• 한국경영과학회지
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• 제24권4호
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• pp.1-12
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• 1999

This paper presents a DEA-AHP hybrid model to evaluate and select R&D projects. AHP collects and processes information on the weights of evaluation criteria. The processed information is used as an input for DEA/AR model. Only desirable number of projects are selected by the hybrid model. The model is examined by an example generated from a real data set.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1996년도 춘계공동학술대회논문집; 공군사관학교, 청주; 26-27 Apr. 1996
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• pp.285-288
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• 1996

This paper deals with an (s, S) spare-part inventory model with general leadtime. In the model, if the inventory level falls to a reorder point s, a replenishment order quantity Q is ordered. Assumming that the number of operating units is one and the lifetime of a unit follows an exponential distribution, we derive the expected cost rate and suggest a procedure to obtain the optimal pair of (s, S) minimizing the cost rate.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1996년도 춘계공동학술대회논문집; 공군사관학교, 청주; 26-27 Apr. 1996
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• pp.675-678
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• 1996

While a large number of firms have already developed and use an executive information system (EIS) effectively, some firms are reluctant to build one for lack of appropriate and well-organized guidance on how to achieve their own project. In this paper we suggest an EIS development methodology by testing five research hypotheses. As a result, we can conclude that prototyping should be applied to be combined with the SDLC. Moreover the preliminary stage accomplished the highest score in the eight-stage process.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 1989년도 추계학술발표회 발표논문초록집; 이화여자대학교, 서울; 23 Sep. 1989
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• pp.91-107
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• 1989

New product concept evaluation is one of the most important activities among many possible evaluation activities involved in the whole new product process. This paper aims at exploring the applicability of the Analytic Hierarchy Process(AHP) to this new product concept evaluation. To this aim, an AHP based concept evaluation model was formulated and explained using an illustrative example. A number of issues were also raised and discussed concerning the applicability of AHP to out problem. Finally, some further research areas were identified.

• Communications for Statistical Applications and Methods
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• 제7권3호
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• pp.643-654
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• 2000

In this paper, we review some class of t-norms on which fuzzy arithmetic operations preserve the shapes of fuzzy numbers and the Hausdorff-distance between fuzzy numbers as the measure of distance between fuzzy numbers. And we suggest the least Hausdorff-distance square method for fuzzy linear regression model using shape preserving fuzzy arithmetic operations.

• 한국국방경영분석학회지
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• 제12권1호
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• pp.50-70
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• 1986

When the ICM is fired in the artillery weapon, it is necessary to determine rounds of munitions for sufficient damage to targets of different sizes and shapes. This paper analyzes all kinds of delivery errors involved in ICM firing, and then develops the target coverage model appropriate for ICM salvos. This model is evaluated through computer simulation. The expected target coverage is measured according to number of salvos, range and probable error, velocity error, battery arrangement, target size, and shell reliability respectively.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2004년도 추계학술대회 및 정기총회
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• pp.375-388
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• 2004

As today's business environment has become more and more competitive, forward as well as backward flows of products among members belonging to a supply chain have been increased. The backward flows of products, which are common in most industries, result from increasing amount of products that are returned, recalled, or need to be repaired. Effective management for these backward flows of products has become an important issue for businesses because of opportunities for simultaneously enhancing profitability and customer satisfaction from returned products. Since third party logistics service providers (3PLs) are playing an important role in reverse logistics operations, the 3PLs should perform two simultaneous logistics operations for a number of different clients who want to improve their logistics operations for both forward and reverse flows. In this case, distribution networks have been independently designed with respect to either forward or backward flows so far. This paper proposes a mixed integer programming model for the design of network integrating both forward and reverse logistics. Since this network design problem belongs to a class of NP-hard problems, we present an efficient heuristic based on Lagrangean relaxation and apply it to numerical examples to test the validity of proposed heuristic.