• 한국경영과학회지
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• 제42권3호
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• pp.1-12
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• 2017

In this paper, we generalize lifted inequalities to a 0-1 mixed-integer bilinear covering set with linear terms. This work is motivated by the observation that Generalized Bilinear Inequality (GBI) occurs in the Branch and Bound process. We find some conditions and prove the subadditivity of lifting functions for lifting to be sequence-independent. Using the theoretical results, we develop facet-defining inequalities for a GBI-defined set through three steps of lifting.

• 한국국방경영분석학회지
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• 제30권1호
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• pp.48-69
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• 2004

An optimal allocation model for SAM-X by using a set covering model is suggested. This allocation model considers to guarantee the maximum security of vital areas from the attack of enemy aircraft(s) and missiles. In order to formulate this model, we applied the concept of parallel structure reliability to set covering model. This model gives both direction of the primary target line and location of the facility. When applied this model to the real situation, the solution of this model can be used to the references of decision making for the optimal military facility allocation.

• Korean Journal of Mathematics
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• 제22권3호
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• pp.455-462
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• 2014

Let D be an integral domain with Spec(D) finite, K the quotient field of D, [D,K] the set of rings between D and K, and SFc(D) the set of semistar operations of finite character on D. It is well known that |Spec(D)| ${\leq}$ |SFc(D)|. In this paper, we prove that |Spec(D)| = |SFc(D)| if and only if D is a valuation domain, if and only if |Spec(D)| = |[D,K]|. We also study integral domains D such that |Spec(D)|+1 = |SFc(D)|.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2007년도 추계학술대회 및 정기총회
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• pp.134-137
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• 2007

Unlike the mean-variance approach, the stochastic dominance approach is to form a portfolio that stochastically dominates a predetermined benchmark portfolio such as KOSPI. This study is to search a set of portfolio weights for the first degree stochastic dominance with maximum expected return by managing the constraint set and the objective function separately. An algorithm was developed and tested with promising results against Korean stock market data sets.

• 한국경영과학회지
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• 제34권4호
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• pp.153-163
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• 2009

Unlike the mean-variance approach, the stochastic dominance approach is to form a portfolio that stochastically dominates a predetermined benchmark portfolio such as KOSPI. This study is to search a set of portfolio weights for the first-order stochastic dominance with maximum expected return by managing the constraint set and the objective function separately. A nonlinear programming algorithm was developed and tested with promising results against Korean stock market data sets.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2006년도 춘계공동학술대회 논문집
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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.

• 한국경영과학회지
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• 제15권2호
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• pp.97-104
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• 1990

The problem is a variation of the weighted set-covering problem (SCP) which requires the minimum-cost cover to be self-covering. It is shown that direct extension of the well-known greedy heuristic for SCP can have an arbitrarily large error in the worst case. It remains an open question whther these exists a greedy heuristic with a finite error bound.

• 한국정보과학회논문지:시스템및이론
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• 제31권1_2호
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• pp.102-111
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• 2004

단순 다각형 P의 가시성 다각형을 점이나 에지와 같은 P에서의 가시원으로부터 가시적인 점들의 집합을 말한다. 가시성 다각형은 점들의 ,집합이므로 가시성 다각형들에 대해 교집합, 합집합, 차집합 등과 같은 집합 연산을 수행할 수 있다. 두 가시성 다각형의 교집합은 해당되는 두 가시원으로부터 동시에 보이는 점들의 집합이고, 합집합은 하나 이상의 가시원으로부터 보이는 점들의 집합이다. 두 가시성 다각형의 차집합은 하나의 가시원으로부터만 보이는 점들의 집합이다. 모두 n개의 정점을 가진 두 개의 일반적인 다각형에 대해 집합 연산을 수행하는 기존의 알고리즘으로 가장 효율적인 알고리즘은 O(nlogn + k) 시간이 소요된다, k는 집합 연산의 출력의 크기이다. 그러나 본 논문에서는 가시성 다각형의 특성을 이용하여 O(n) 시간에 교집합, 합집합, 차집합을 구하는 최적인 알고리즘을 제시한다.

• 한국경영과학회지
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• 제22권3호
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• pp.99-111
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• 1997

We consider a production system with post-operation and early set-up. As soon as there are no more units(raw materials) to process and the machine becomes idle, it undergoes a post-operation. After the post operation, if the number of waiting units is greater than or equal to m, it begins a set-up. After the set-up, if the number of units is greater than or equal to N($\geq$m), it begins to process the units. We first analyze the system by employing the decomposition property of the vacation queue. We, then, propose an algorithm that finds the optimal threshold values ($m^*$, $N^*$). Finally we present some numerical examples and interprete the system behavior.

• 한국경영과학회지
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• 제30권4호
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• pp.151-161
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• 2005

For Internet service providers (ISPs), there are three common types of interconnection agreements : private peering, public peering and transit. One of the most important problems for a single ISP is to determine which other ISPs to interconnect with, and under which agreements. The problem can be then to find a set of private peering providers, transit providers and Internet exchanges (IXs) when the following input data are assumed to be given : a set of BGP addresses with traffic demands, and a set of potential service providers (Private peering/transit providers and IXs) with routing information, cost functions and capacities. The objective is to minimize the total interconnection cost. We show that the problem is NP-hard, give a mixed-integer programming model, and propose a heuristic algorithm. Computational experience with a set of test instances shows the remarkable performance of the proposed algorithm of rapidly generating near-optimal solutions.