• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 동계학술발표대회 논문집
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• pp.351-356
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• 2008

When various kinds of outputs are produced from a single energy system, the methodology which allocates the common cost to each output cost is very important because it is directly related with the profit and loss of producers and purchasers. In the cost allocation methodology of the heat and the electricity on a cogeneration, there are energy method, work method, proportional method, benefit distribution method, various exergetic methods, and so on. On the other hand, we have proposed a worth evaluation method which can be applied to any system. The definition of this methodology is that the unit cost of a product is proportion to the worth. Where, worth is a certain evaluating basis that can equalize the worth of products. In this study, we applied this methodology to a gas-turbine cogeneration which produces 119.2 GJ/h of electricity and 134.7 GJ/h of heat, and then we allocated 3,150 $/h of fuel cost to electricity cost and heat cost. Also, we compared with various cost allocation methods. As the result, we conclude that exergy of various kinds of worth basis evaluates the worth of heat and electricity most reasonably on this system.

• 설비공학논문집
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• 제21권4호
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• pp.252-259
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• 2009

When various kinds of outputs are produced from a single energy system, the methodology which allocates the common cost to each output cost is very important because it is directly related with the profit and loss of producers and purchasers. In the cost allocation methodology of the heat and the electricity on a cogeneration, there are energy method, work method, proportional method, benefit distribution method, various exergetic methods, and so on. On the other hand, we have proposed a worth evaluation method which can be applied to any system. The definition of this methodology is that the unit cost of a product is proportion to the worth. Where, worth is a certain evaluating basis that can equalize the worth of products. In this study, we applied this methodology to a gas-turbine cogeneration which produces 119.2 GJ/h of electricity and 134.7 GJ/h of steam, and then we allocated 3,150 $/h of fuel cost to electricity cost and steam cost. Also, we compared with various cost allocation methods. As the result, we conclude that reversible work of various kinds of worth basis evaluates the worth of heat and electricity most reasonably.

• 한국국방경영분석학회지
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• 제7권1호
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• pp.53-80
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• 1981

This paper explores a rational investment decision model in sequential capital allocation process under capital rationing. A method is proposed for measuring the new investment decision factor which is the flexibility that describes the future availability of invested funds. This flexibility is important in sequential decision process. Also presented is a multiobjective (MO) decision model into which flexibility is incorporated with the profit and risk factors. The effectiveness of this criterion is compared with the expected present value and the mean-semivariance criteria through a simulation model.

• Management Science and Financial Engineering
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• 제2권1호
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• pp.19-51
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• 1996

We suggest a distributed framework for task assignment in the computer-controlled shop floor where each of the resource agents and part agents acts like an independent profit maker. The job allocation problem is formulated as a linear programming problem. The LP formulation is analyzed to provide a rationale for the distributed task assignment procedure. We suggest an auction based negotiation procedure including a price-based bid construction and a price revising mechanism. The performance of the suggested procedure is compared with those of an LP formulation and conventional dispatching procedures by simulation experiments.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2014년도 춘계학술대회
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• pp.319-322
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• 2014

최근 인터넷이 활성화 되면서 물류기업의 수 배송 물량이 증가하고 있으나, 제한된 차량과 차주를 확보하는 것이 용이하지 않기 때문에, 수 배송 업무의 합리화는 국내 기업들의 물류관리에서 가장 중요한 과제 중의 하나이다. 이에 따라, 차주와 차량의 효율적 배차 계획 수립을 위해 차량경로 문제와 차량일정계획문제를 해결하기 위한 많은 연구가 있었다. 그러나, 매일 변동하는 교통상황과 세밀한 지리적인 조건을 반영하기 어렵고 지점수가 많아질수록 방대한 크기의 데이터베이스 구축이 필요할 뿐만 아니라 계산시간의 증가로 인한 비효율성이 야기될 수 있다. 본 논문에서는 다양한 제약조건을 가지는 3PL 물류업체의 운송비용에 따른 배차계획 문제를 다루며, 문제 해결을 위해 배차 정보 구축과 운송비용을 고려한 배차 알고리즘을 제안하고 이를 물류업체에 적용한 실험 결과를 제시하였다. 개발된 운송비 기반 배차시스템을 적용해 본 결과 차주의 기존 운송비 수익이 평균 11% 상승하였다.

• 한국통신학회논문지
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• 제29권10B호
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• pp.866-879
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• 2004

본 연구논문에서는 소비자의 서비스 품질에 따른 지불의사를 고려하여 음성/데이터 통합 이동통신서비스 제공업자의 수익을 극대화시키는 최적 가격을 결정하는 모델을 제시한다. 특히 고려되는 음성서비스 및 데이터서비스의 가격방식은 현재 우리나라 이동통신서비스의 회선요금제와 패킷요금제를 각각 적용한다. 이 모델은 소비자들이 핸드오프도중 발생하는 통화단절에 매우 민감하게 반응한다는 가정하에, 기지국이 무선채널을 할당함에 있어서 핸드오프 트래픽만이 독점사용할 수 있는 가드채널을 할당하는 방안을 고려하며, 더불어 서비스제공업자가 통화단절율의 서비스 품질을 소비자군에게 보장하는 경우를 고려한다. 궁극적으로 이 모델은 단기적으로 가격전략 및 무선채널 할당정책에 의존하여 서비스 품질을 개선$.$보장할 수 있는 방안을 제시하며, 그 결과 시스템자원의 확충없이는 수익과 서비스 품질의 개선$.$보장간에 상충관계가 존재함을 보여준다.

• Spatial Information Research
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• 제12권2호
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• pp.211-228
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• 2004

본 연구는 대전시를 사례로 하여 주유소의 입지적 특성과 판매권역을 분석하기 위해 설문과 면접 조사, 그리고 GIS의 그리드 분석을 활용하였다. 주유소의 입지적 특성을 분석해 본 결과 고수익 입지유형은 인구밀도와 1일 통행량이 일정수준 이상으로 배후 상주인구와 통행인구가 많아 고수익이 예상되었고, 반면에 저수익 입지유형은 토지이용상 녹지와 개발제한구역 등으로 통행량도 낮아서 높은 수익을 기대하기 어려웠다. 대전시 인구수에 기반하여 판매권역의 공간분포 패턴을 살펴본 결과, 주유소 판매권역의 크기는 인구밀도가 조밀한 중심지역에서 인구밀도가 낮은 외곽지역으로 갈수록 확대되었다. 또한 인구수에 대비하여 주유소가 과다한 주유소 과밀지역과 과소 지역이 분포하는 불균형적 주유소 분포패턴을 보여주었다. 입지-배분모델을 적용한 결과 주유소 과밀 지역에서는 주유소의 수가 줄어들었고, 과소한 지역에서는 신규로 주유소가 입지하여 보다 균형적인 분포패턴을 보여주었다. 이와 같은 연구결과는 석유제품 유통기관별로 최소 배후지 규모를 만족시키면서 균형적 공간 분포패턴을 가질 수 있도록 배치하는데 필요한 기초적인 자료로 활용될 수 있을 것으로 예상된다.

• Industrial Engineering and Management Systems
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• 제11권2호
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• pp.155-164
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• 2012

As the global market becomes more competitive, manufacturing industries face relentless pressure caused by a growing tendency of greater varieties of products, shorter manufacturing cycles and more sophisticated customer requirements. Efficient and effective supplier selection and order allocation decisions are, therefore, important decisions for a manufacturer to ensure stable material flows in a highly competitive supply chain, in particular, when customers are willing to accept products with less desirable product attributes (e.g., color, delivery date) for economic reasons. This paper attempts to solve optimally the challenging problem of supplier selection and order allocation, taking into consideration the customer flexibility for a manufacturer producing multi-products to satisfy the customers' demands in a multi period planning horizon. A new mixed integer programming model is developed to describe the behavior of the supply chain. The objective is to maximize the manufacturer's total profit subject to various operating constraints of the supply chain. Due to the complexity and non-deterministic polynomial-time (NP)-hard nature of the problem, an improved genetic approach is proposed to solve the problem optimally. This approach differs from a canonical genetic algorithm in three aspects: a new selection method to reduce the chance of premature convergence and two problem-specific repair heuristics to guarantee feasibility of the solutions. The results of applying the proposed approach to solve a set of randomly generated test problems clearly demonstrate its excellent performance. When compared with applying the canonical genetic algorithm to locate optimal solutions, the average improvement in the solution quality amounts to as high as ten percent.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권4호
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• pp.1192-1207
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• 2014

Dynamic spectrum sharing is a key technology to improve spectrum utilization in wireless networks. The elastic spectrum management provides a new opportunity for licensed primary users and unlicensed secondary users to efficiently utilize the scarce wireless resource. In this paper, we present a game-theoretic framework for dynamic spectrum allocation where the primary users rent the unutilized spectrum to the secondary users for a monetary profit. In reality, due to the ON-OFF behavior of the primary user, the quantity of spectrum that can be opportunistically shared by the secondary users is limited. We model this situation with the renewal theory and formulate the spectrum pricing scheme with the Bertrand game, taking into account the scarcity of the spectrum. By the Nash-equilibrium pricing scheme, each player in the game continually converges to a strategy that maximizes its own profit. We also investigate the impact of several properties, including channel quality and spectrum substitutability. Based on the equilibrium analysis, we finally propose a decentralized algorithm that leads the primary users to the Nash-equilibrium, called DST. The stability of the proposed algorithm in terms of convergence to the Nash equilibrium is also studied.

• Industrial Engineering and Management Systems
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• 제8권4호
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• pp.221-227
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• 2009

There are customer services jointly provided by two facilities so that each customer will complete the course made up of both facilities' sub-services. The two facilities are assumed invested respectively by an infrastructure owner and one subordinate facility owner, whose partnership is built on their capital investments. This paper presents a mathematical model of Stackelberg competition between the two facility owners to derive their optimal Nash equilibrium. In this study, each facility owner's profit is consisted of fixed revenue fractions of sold services, operating costs (including depreciation cost) and maintenance costs of her facility. The maintenance costs of one facility are incurred both by failures and deterioration due to usage. Moreover, for both facilities, failures are rectified immediately by minimal repairs and preventive maintenance is carried out at a fixed time epoch. Additional assumptions are also employed to develop the model such as customer arrivals are manipulated to follow a Poisson process, and each facility's lifetime is independently Weibull-distributed. The Stackelberg game proceeds as follows. At the first stage of decision making process, the infrastructure owner (acting as a leader) decides the allocation of revenue shares based on her self-interest. After observing the allocation of revenue shares, the subordinate facility owner determines her own optimal price of services. This paper investigates actions and reactions of the two partners in the system. Then analytical conditions are proposed to achieve a unique optimal Nash equilibrium. Finally, some suggestions for further research are discussed.