• 유통과학연구
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• 제20권6호
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• pp.125-135
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• 2022

Purpose: The revenue sharing contract has been used in various industries and it is expected to coordinate the individual companies' operations in a way to improve the whole supply chain performance. This study evaluates the performance of the revenue sharing contract to find out whether this contract achieves its original goal, the supply chain coordination. Research design, data, and methodology: The profit optimization models are developed to represent two stage supply chain system with a supplier and a buyer. By using the numerical examples of the proposed mathematical models, this study examines whether this supply chain contract coordinates the supply chain system. Results: The numerical examples show that the revenue sharing contract does not make the same supply chain profit as the centralized system does. With the proper combination of the wholesale price discount rate and revenue share ratio, both manufacturer and retailer can obtain increased profits from the revenue sharing contract. Conclusions: The outcomes of the numerical analysis imply that the revenue sharing certainly improves the supply chain performance but it does not fully coordinate the supply chain system. By controlling the wholesale price and revenue share ratio, every supply chain member can be beneficiaries of this supply chain contract.

• 한국인터넷방송통신학회논문지
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• 제16권2호
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• pp.181-188
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• 2016

본 논문은 경제급전 최적화 문제에 개별 발전회사별로 독립적으로 경제급전을 수행하는 방법에 비해 중앙에서 통합하여 경제급전 최적화를 수행하는 경우가 보다 경제적임을 보였다. 이 경우에 적용된 알고리즘으로 밸브지점으로 발전량을 조절하는 균형방법을 수행한 후 발전량을 감소시킬 때의 비용 감소분과 증가시킬 때의 비용 증가분 차이로 발전량을 상호 교환하는 방법으로 최적화를 수행하였다. 10대, 13대과 40대-발전기를 독립적으로 운영하는 경우와 통합된 63대-발전기를 경제급전하는 경우를 비교한 결과 통합운영 방법이 독립적 경제급전에 비해 발전비용을 획기적으로 감소시켜 경제적인 이익을 극대화 시킬 수 있음을 보였다.

• 한국컴퓨터정보학회논문지
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• 제19권10호
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• pp.169-173
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• 2014

최적 해를 다항시간으로 얻을 수 있는 알고리즘이 알려져 있지 않은 NP-완전인 상자포장 문제의 일종인 바지선 적재 문제에 대해, Gu$\acute{e}$ret et al.은 $O(m^4)$ 수행 복잡도의 선형계획법으로 해를 얻고자 하였다. 반면에, 본 논문에서는 이득 우선순위로 적재하는 규칙인 O(m log m) 복잡도의 알고리즘을 제안하였다. 제안된 방법은 첫 번째로 이득 우선순위를 결정하였다. 다음으로, 이득 우선순위 물품들을 바지선에 적재하는 방법으로 초기 적재 결과를 얻었다. 마지막으로, 바지선 적재 용량을 미달하는 경우, 이전에 적재된 물품과 미선적된 물품을 상호 교환하여 바지선 적재용량을 충족시켰다. 실험 결과, 제안된 알고리즘은 NP-완전 문제인 바지선 적재 문제에 대해 선형계획법의 $O(m^4)$를 O(m log m)으로 단축시켰다.

• Korean Chemical Engineering Research
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• 제58권2호
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• pp.209-223
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• 2020

석유화학 제품, 컴파운드(Compound), 전지, IT 소재, 첨단소재, 제약 등 다양한 제품 군의 사업을 보유하고 있는 화학 회사에서 각 사업 부분에 있어 수요 예측, 물류, 생산, 재고, 원재료 공급의 SCM (Supply Chain Management)은 사업의 손익과 직접적으로 연결되기 때문에 그와 관련된 최적화와 시스템 역량 수준은 매우 중요하다. 본 연구는 다양한 사업 군에서 각각의 SCM이나 비효율적 영역을 개선하는 등의 역량을 고도화하기 위해 원재료를 공급하고, 제품을 생산하기 위한 공급/생산 계획 등에 있어서 수학적 최적화 방법을 적용한 사례에 관하여 다룰 것이다. 그리고 학술적인 연구에 그치는 것이 아니라 계획 수립 담당자가 실제로 자신의 일부 업무에 활용하는 것이 중요하므로 이를 위해 추가적으로 필요한 사항들을 서술하였고 각각의 적용 성과를 표현하였다. 소개가 될 사례의 첫 번째에서는 편광판 생산에 있어서 원재료 로스(Loss)를 최소화하는 것을 기반으로 하는 공급계획 최적화, 최적 손익 사업 운영계획, 편광판 연신 생산 공정의 스케줄(Schedule) 최적화를 다룰 것이다. 두 번째 사례로는 PO (Poly Olefin) 공정의 생산성 극대화를 위한 생산/포장계획 최적화에 관하여 다룰 것이고, 세 번째 사례로는 전지 생산에 있어서 전극 모델 교환을 최소화 시키는 생산계획 최적화에 대해 다룰 것이다. 네 번째로는 석유화학 특성상 선박으로 대부분의 원료 입하 및 제품 출하를 하기 때문에 한정된 부두에 여러 가지 원료 입고와 제품 출하를 위한 선박이 접안 하는 일정을 최적화 한 사례를 다룰 것이며, 마지막으로 ABS (Acrylonitrile Butadiene Styrene) 반제품 생산에 있어서 제품 Change를 최소화 하는 생산계획 최적화를 다룰 것이다.

• 유통과학연구
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• 제15권8호
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• pp.15-28
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• 2017

Purpose - Many researchers analyze VMI as a supply chain collaboration program to reveal its true value. Most of them focus on the dyadic relationship in two stage supply chain systems. This study examines the effect of VMI when it is applied to the different parts of three stage supply chain systems. Research design, data, and methodology - Based on three stage supply chain, this study compares three different systems including full VMI, partial VMI, and non-VMI by using mathematical models. The performances of three systems are compared with the numerical examples of the proposed supply chain models. Results - The numerical examples reveal that full VMI where the manufacturer controls inventories at all stages outperforms any other systems in terms of the system profit and enables all individual members to gain greater profits than non-VMI. Meanwhile, under partial VMI where VMI is implemented between the wholesaler and retailer, only these two members improve their performances and the manufacturer who does not belong to VMI makes less profit than even under non-VMI. This study also examines the impact of market size and profit margin on the system performance. Conclusions - The result of this study supports the common belief that VMI secures the best result when it is applied to the entire supply chain system. The additional findings from the numerical analysis are discussed.

• 한국경영과학회지
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• 제23권1호
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• pp.97-107
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• 1998

This paper is concerned with a parallel system that sustains a time-independent load and consists of n components with exponential lifetimes. It is assumed that the total load is shared by the working components and the failures of components increase higher failure rates in the surviving components according to the relationship between the load and the fialure rates. The power rule model among several load-failure rate relationships is considered. We consider the system efficiency meausre as the expected profit earned by the system per unit time. The high load causes high gain but it also occurs frequent system failures. The expected profit per unit time is used as criterion to evaluate the system efficiency. The goal of system engineer is to determine the optimal load and redundant units maximizing the expected profit per unit time. First, the system reliability function is obtained and the optimization problem of the load-sharing parallel system is considered. Given the redundant units, the existence of the optimal load can be proved analytically and given the load, the optimal redundant units can be solved also analytically. The optimal load and redundant units are obtained simultaneously by numerical computation. Some numerical examples are studied.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 추계학술대회 논문집 전력기술부문
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• pp.457-459
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• 2008

This paper presents the optimization of CHP (Combined heat and power) plant under deregulated market. In this case, a boiler is added as different source for heat providing, that gives flexible and efficient operation for the plant. The purpose of optimization is to maximize the profit in period of 24 hours by making unit commitment decision, called "optimal policy". In this paper, Dynamic Programming method is introduced as the effective and efficient method. Finally, an example is solved to illustrate the optimal Policy of such a CHP and boiler.

• Journal of Power Electronics
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• 제9권6호
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• pp.919-928
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• 2009

Microgrids (MGs) are typically comprised of distributed generators (DGs) including renewable energy sources (RESs), storage devices and controllable loads, which can operate in either interconnected or isolated mode from the main distribution grid. This paper introduces a novel dynamic programming (DP) approach to MG optimization which takes into consideration the coordination of energy supply in terms of heat and electricity. The DP method has been applied successfully to several cases in power system operations. In this paper, a special emphasis is placed on the uncontrollability of RESs, the constraints of DGs, and the application of demand response (DR) programs such as directed load control (DLC), interruptible/curtaillable (I/C) service, and/or demand-side bidding (DSB) in the deregulated market. Finally, in order to illustrate the optimization results, this approach is applied to a couple of examples of MGs in a certain configuration. The results also show the maximum profit that can be achieved.

• 제어로봇시스템학회논문지
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• 제12권12호
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• pp.1184-1190
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• 2006

Most chemical companies try to maximize their energy efficiencies due to high oil price and reinforcement of environmental regulation. An individual factory continuously has tried to reduce energy consumption or carbon dioxide discharge for high profit. Nevertheless, it is found that waste heat is disposed with forms of low or medium pressure steams. It can be improved by the aspect of entire industrial complex. Therefore, we have developed a steam network optimization method using Steam Networking Matrices(SNMs) in this research. Results from an illustrative example show that energy consumption can be reduced by optimizing steam exchange networks.

• 제어로봇시스템학회논문지
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• 제12권12호
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• pp.1169-1172
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• 2006

The prices of chemical products are fluctuated by several factors. The chemical companies can't predict and be ready to all of these changes, so they are exposed to the risk of a profit fluctuation. But they can reduce this risk by making a well-diversified product portfolio. This problem can be thought as the optimization of the product portfolio. We assume that the profits come from the 'spread' between a naphtha and a chemical product. We calculate a mean and a variation of each spread and develop an automatic module to calculate the optimal portion of each product. The theory is based on the Markowitz portfolio management. It maximizes the expected return while minimizing the volatility. At last we draw an investment selection curve to compare each alternative and to demonstrate the superiority. And we suggest that an investment selection curve can be a decision-making tool.