• 한국산업융합학회 논문집
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• 제26권5호
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• pp.855-866
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• 2023

With the rapid advancement and sophistication of defense weapon systems, the government, military, and the defense industry have conducted various innovative attempts to improve the efficiency of post-logistics support(PLS). The Ministry of Defense has mandated RAM-C(Reliability, Availability, and Maintainability-Cost) analysis as a requirement according to revised Total Life Cycle System Management Code of Practice in May 2022. Especially, for the project budget forecast of new PBL(Performance Based Logistics) business contacts, RAM-C is recognized as an obligatory factor. However, relevant entities have not officially provided guidelines or manuals for RAM-C analysis, and each defense contractor conducts RAM-C analysis with different standards and methods to win PBL-related business contract. Hence, this study aims to contribute to the generalization of the analysis procedure by presenting a cost analysis case based on RAM-C for the supply of military depot maintenance PBL project. This study presents formulas and procedures to determine requirements of military depot maintenance PBL project for repair parts supply. Moreover, a sensitivity analysis was conducted to find the optimal cost/utilization ratio. During the process, a correlation was found between supply delay and total cost of ownership as well as between cost variability and utilization rate. The analysis results are expected to provide an important basis for the conceptualization of the cost analysis for the supply of military depot maintenance PBL project and are capable of proposing the optimal utilization rate in relation to cost.

• 한국국방경영분석학회지
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• 제11권2호
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• pp.15-22
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• 1985

Planning for the expansion of production capacity is of vital importance in many applications within the private and public sectors. This paper considers a sequencing expansion problem in which capacity can be added only at discrete points in time. Given the demand forecast of each period, capacity and cost of each expansion project, we are to determine the sequence of expansion necessary to provide sufficient capacity to meet the demand in all periods at minimum cost. This problem is formulated as a pure integer programming and solved by branch and bound method using Lagrangian relaxation. At first, simple sequencing expansion problem is presented, and in the latter part, extension to include precedence between projects is suggested.

• 한국산업경영시스템학회:학술대회논문집
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• 한국산업경영시스템학회 2002년도 춘계학술대회
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• pp.343-348
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• 2002

We are concerned with a long-term replenishment contract for the ARIMA demand process in a supply chain. The chain is composed of one supplier, one buyer and consumers for a product. The replenishment contract is based upon the well-known (s, Q) policy but allows us to contract future replenishments at a time with a price discount. Due to the larger forecast error of future demand, the buyer should keep a higher level of safety stock to provide the same level of service as the usual (s, Q) policy. However, the buyer can reduce his purchase cost by ordering a larger quantity at a discounted price. Hence, there exists a trade-off between the price discount and the inventory holding cost. For the ARIMA demand process, we present a model for the contract and an algorithm to find the number of the future replenishments. Numerical experiments show that the proposed algorithm is efficient and accurate.

• 대한산업공학회지
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• 제27권4호
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• pp.345-351
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• 2001

We are concerned with a multiple replenishment contract with a purchase price discount in a supply chain. The chain is composed of one supplier, one buyer and consumers for a product. The replenishment contract is based upon the well-known (s, Q) policy but allows contracting several firmed orders at a time with a price discount. Due to a larger forecast error of the future demand, the buyer should keep a higher level of safety stock to provide the same level of service of the usual (s, Q) policy but can reduce his purchase cost by placing larger quantity. Thus there exists a trade-off between the price discount and inventory holding cost. We present a model for the contract and an algorithm to find the optimum number of the firmed orders. Computer experiments show that the algorithm finds the global optimum solution very fast.

• 산업경영시스템학회지
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• 제11권17호
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• pp.47-54
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• 1988

Korean National Railroad(K.N.R) playing a important role in land transportation gives us many problems to solve considering proper management of National Budget and development of the state of operation by maintaining train parts rationally as public services. According this study is to show inventory provision system for deciding the safety inventory level as the better rational method. Bibliography for this study is limited to only three kinds of seven brakes-shoe which is produced by T workshop in Korean National Railroad. To reduce the holding cost coming from the want of the stock and shortage cost of the stock expected. This study is to present a ratio of shortage on the stock permitted for the last definite period and the demand result forecast per month.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 B
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• pp.704-706
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• 1996

This paper presents a new algorithm of unit commitment for optimal operation in power system. The proposed method developed algorithm that determined generators considering load variations at each stages. It has established forecast unit commitment over time horizon at first and next calculated quality cost of generators and then committed generator that has minimum quality cost at unit commitment schedule over time horizon. It is used that Objet-Oriented Programming for effective realization, and simple handling of complex program. The proposed method has applied at example system and the results has shown superior economics and computational requirement than the conventional method.

• 한국BIM학회 논문집
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• 제12권2호
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• pp.40-48
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• 2022

It is very important to accurately predict construction costs in the early stages of the construction project. However, it is difficult to accurately predict construction costs with limited information from the initial stage. In recent years, with the development of machine learning technology, it has become possible to predict construction costs more accurately than before only with schematic construction characteristics. Based on machine learning technology, this study aims to analyze plans to more accurately predict construction costs by using only the factors influencing construction costs. To the end of this study, the effect of the error rate according to the activation function and the node configuration of the hidden layer was analyzed.

• 디지털융복합연구
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• 제16권5호
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• pp.137-143
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• 2018

우리나라의 항공여객 운송실적은 지속적으로 성장하고 있다. 본 연구에서는 우리나라 항공여객 운송 실적의 성장추이를 확인하기 위해 시스템다이내믹스를 활용한 항공여객 수요예측 모델을 제안하였다. 항공여객 수요예측은 항공여객 운송수요를 종속변수로 하고 국제항공유가, GDP 및 환율을 외생변수로 하여 시뮬레이션 하였다. 모델의 정확도는 MAPE와 $R^2$를 이용하여 검증하였고 검증 결과 제안된 예측모델은 정확한 예측모델로 확인되었다. 수요예측 결과 국적 항공사의 항공여객 처리실적은 앞으로도 지속적으로 성장하며, 특히 저비용항공사의 수송 분담률이 크게 증가할 것으로 예측되었다. 향후 한국에 진출해 있는 외국계 항공사들의 내국인 처리 실적 및 국적항공사들의 Alliance 체결에 따른 실적 등을 추가하여 보다 정확한 항공여객 수요예측 모델을 제안하고자 한다.

• 에너지공학
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• 제17권1호
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• pp.31-37
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• 2008

현재 에너지 효율프로그램에 대한 수요관리 목표량과 투자비는 과거 실적 데이터를 바탕으로 단일한 Bass 확산 모형을 이용하여 산정되고 있다. 국내외적으로 제품 등의 보급량 예측에 널리 사용되는 Bass 확산 모형은 시간과 세 가지 계수들에 대한 함수로 표현되며, 계수들의 추정에 있어서 제품의 과거 실적 데이터의 충분한 확보가 필수적이다. 국내의 경우 에너지 효율 측면에서 고효율기기의 수요관리 목표량 산정을 위해 기기별 보급량 예측이 선행되어야 하며, 기기별 보급량 예측은 Bass 모형을 근간으로 하고 있다. 그러나 현재 진행 중인 고효율기기 보급 프로그램의 조명기기, 인버터, 자판기와 전동기는 그 진행이 길지 않아 Bass 확산 모형을 이용한 보급량 예측에 필수요건인 충분한 실적 데이터가 존재하지 않은 실정이다. 이는 기기의 미래 보급량 예측에 큰 오차가 발생할 수 있으며 보급 예측량에 대한 정확성을 기대하기 어려우므로 앞으로의 고효율기기의 보급 예측의 방식에 제도적 개선이 필요한 상황이라 할 수 있다. 본 논문에서는 Bass, virtual Bass, Logistic과 Lawrence & Lawton 확산 모형을 이용하여 각 고효율 기기의 미래 보급 확산 추이를 살펴보았다. 또한 기기별 특성에 따른 모형 선호도 평가를 위해 통계랑 기준에 근거하여 실적 데이터와의 오차 범위를 산정하였다. 이 결과를 바탕으로 각 확산 모형을 이용한 기기 보급량 예측에 있어서 확산 모형의 단순 적용에 따른 오차 발생 원인과 기기별 특성에 따른 확산 모형 선호도를 분석하였다.

• 한국조리학회지
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• 제15권2호
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• pp.231-242
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• 2009

호텔 연회에서 가장 중요한 정보 중 하나는 매출액 자료이다. 매출액 예측은 비용을 절감시키고 인력 배분의 효율성을 증가시키고 급변하는 환경에서 경쟁하는 능력을 향상시키는 데 도움이 되는 정보를 제공한다. 본 연구는 국내외 연구에서 적합한 예측모형으로 평가되고 있는 ARIMA 모형을 이용하여 호텔 연회장의 매출액을 예측하였다. 분석을 위해서 사용한 자료는 서울 소재 GI 호텔 연회장의 월별 매출액 자료를 사용하였으며, 분석 결과 SARIMA(2,1,3)(0,1,1)가 최종적으로 추정되었다. 본 연구의 시사점은 국내외 연구에서 적합한 예측모형으로 평가되고 있는 ARIMA 모델을 호텔 연회장의 월별 매출액 자료에 적용하였다는 점과 호텔 연회 실무자들에게 참고자료로 사용할 수 있는 유용한 정보를 제공하였다는 점을 들 수 있다.