• Nuclear Engineering and Technology
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• 제53권7호
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• pp.2104-2125
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• 2021

This paper presents the verification and validation (V&V) of a calculation module for isotope inventory prediction to control the back-end cycle of spent nuclear fuel (SNF). The calculation method presented herein was implemented in a two-step code system of a lattice code STREAM and a nodal diffusion code RAST-K. STREAM generates a cross section and provides the number density information using branch/history depletion branch calculations, whereas RAST-K supplies the power history and three history indices (boron concentration, moderator temperature, and fuel temperature). As its primary feature, this method can directly consider three-dimensional core simulation conditions using history indices of the operating conditions. Therefore, this method reduces the computation time by avoiding a recalculation of the fuel depletion. The module for isotope inventory calculates the number densities using the Lagrange interpolation method and power history correction factors, which are applied to correct the effects of the decay and fission products generated at different power levels. To assess the reliability of the developed code system for back-end cycle analysis, validation study was performed with 58 measured samples of pressurized water reactor (PWR) SNF, and code-to-code comparison was conducted with STREAM-SNF, HELIOS-1.6 and SCALE 5.1. The V&V results presented that the developed code system can provide reasonable results with comparable confidence intervals. As a result, this paper successfully demonstrates that the isotope inventory prediction code system can be used for spent nuclear fuel analysis.

• 대한안전경영과학회지
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• 제2권4호
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• pp.209-217
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• 2000

In this paper, we consider an Inventory system with multi-suppliers. A supply agreement is made with one of the suppliers, to deliver a fixed quantity Q evry review period ； That is, adapting to discounts of under the condition of free addition often implies that the timing and sizes of future replenishment orders are less predetermined. The replenishment decisions for the other supplier are governed by a replenishment policy. This paper, multiple suppliers strategy is a combination of a push system (the main supplier delivers every review period a predetermined quantity Q) and a pull system the replenishment orders placed at other suppliers are governed by replenishment policy. The costs are defined as the sum of the ordering, holding, purchasing and opportunity costs. Based on numerical results, conclusions follow about the division of the replenishment volume among the inventory policy.

• 대한안전경영과학회지
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• 제8권2호
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• pp.115-128
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• 2006

The study analyzes those relations of customer service level of each sales branch, level of cooperations among branches, and overall system-wide service level for an item. Under the continuous review method, each sales branch places an order to the outside supplier, and the each branch receives the order quantity after elapsing a certain lead time. Under these circumstances, those branches with stockout condition may be supplied by other branches with keeping stocks to cover the shortages. This policy generally increases the system-wide customer service level for an item throughout cooperations for the safety plan among branches. Therefore, in the context of inventory policy, the decision rules to determine the proper branch levels of service and cooperation levels of service are important goals in terms of attaining desired system-wide service level. This research has suggested the method and procedure to reach above goals.

• 대한안전경영과학회지
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• 제9권4호
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• pp.121-127
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• 2007

CSP(Concurrent Spare Parts) is supplied with the procurement of new equipment or weapon system and is used to sustain the equipment without resupply during the initial coverage period. This study is concerned with a problem of determining the near optimal inventory level of the spare parts, especially Concurrent Spare Parts. For this, we utilize the mixed periodic and continuous review polices considering the CSP and (r,Q) Policies concurrently in a two-echelon distribution system. We propose the mathematical model to minimize the total cost which is composed with ordering cost, purchasing cost, holding cost, and stickout cost. If the mixed policy is compared to other policies(CSP, (r,Q)), the proposed methodology performs well and is best policy in the equipment maintenance expenses.

• 대한공간정보학회지
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• 제18권4호
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• pp.71-77
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• 2010

도로절토사면유지관리시스템은 국도를 따라 위치한 절토사면의 붕괴를 예방하고자 고안된 체계적인 유지관리시스템을 말한다. 안전한 도로 관리를 추구하기 위한 시스템을 수행할 목적으로 한국건설기술연구원은 2006년부터 전국 모든 절토사면에 대한 현황 파악 및 데이터베이스를 구축해 오고 있다. IT 기술 응용의 일환으로 GIS기술과 내비게이션 기술을 이용하여 절토사면관리시스템(SLOPE-Navi.)을 개발하였다. 내비게이션 절토사면 데이터관리시스템을 통하여 이전에 구축된 자료에 대한 점검 및 검증을 수행하여, 28,707개의 절토사면 기초조사 자료 및 정밀조사 자료를 내비게이션 지도 내에 수록하였다. 내비게이션 절토사면 데이터 관리시스템은 체계적이고 효율적인 절토사면 DB 관리 및 운용으로 붕괴 사고 예방 및 대책 수립을 위한 현장관리시스템으로 활용성이 클 것으로 판단된다.

• 한국경영과학회지
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• 제39권4호
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• pp.153-165
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• 2014

We present a new framework for rental capacity management in which rental capacity is dynamically managed by means of temporary inventory addition/return. While serving customers with its own (native) capacity, the rental firm rents additional rental capacity from an upper echelon rental company so that it can avoid lost sales which may occur when stock is not sufficient, and returns it when stock becomes sufficiently large enough to cope with demands. Formulating the model as a Markov decision process, we investigate a flexible capacity addition/return policy that maximizes the firm's profit with respect to system costs. Numerical study indicates that rental operation with capacity addition/return can be economically favorable over rental operation without capacity expansion/return and can contribute the reduction in the size of native rental capacity.

• 한국정보통신학회논문지
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• 제17권2호
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• pp.341-346
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• 2013

물류의 입출고 및 재고현황을 신속하고 정확하게 관리하는 것이 매우 중요한 냉동창고 재고관리 프로그램은 폐쇄 클라이언트 서버 환경인 레거시 시스템에서 운용되고 있어 유지보수에 많은 비용과 인력이 소요된다. 이로 인해 소비자인 화주에게 제공되는 서비스가 전무하며, 기본적인 수 발주를 위해서 팩스나 전화를 이용하므로 업무 프로세스가 낙후되어 업무가 비효율적이며 오류와 부정확성 등의 문제가 발생하고 있다. 본 논문에서는 낙후된 기존 시스템의 문제와 냉동창고 소비자인 화주에게 제공되는 서비스가 없는 문제를 해결하기 위해 기존 시스템을 그대로 유지하면서 모바일로 화주에게 다양한 서비스를 제공하는 모바일 프레임워크를 설계하고 구현한다. 구현된 시스템에서 화주는 모바일기기를 이용하여 수 발주 업무, 재고량 조회 등의 서비스를 제공받아 관리 업무의 신속성과 정확성을 보장하였으며 다양한 서비스를 화주에게 제공함으로써 사용자만족도를 향상시켰다.

• 산업경영시스템학회지
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• 제36권4호
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• pp.31-37
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• 2013

In this paper, we develop an efficient approach to solve a continuous review inventory system with a budget constraint when the semi-finished product and optional components are required to be assembled. We are, in particular, interested in a budget constraint that includes a service level. The service cost, such as labor and facility costs, tends to increase as the service level increase, and it makes the problem difficult to solve. Assuming that the reorder point for a semi-finished product is given, we show that the order quantity for the semi-finished product and the order quantity and reorder point for optional components can be determined by minimizing the total cost that includes setup cost, inventory holding cost, and shortage cost. The performance of the proposed approach is tested by numerical examples. By using sensitivity analysis, we conclude that, as the reorder point for semi-finished product increases, the order quantity for semi-finished product increases, whereas the order quantity and reorder point of optional components decreases.

• 디지털융복합연구
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• 제13권9호
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• pp.77-87
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• 2015

VMI(벤더 관리형 재고)는 소매업자에 있는 재고가 제조자나 벤더에 의해 모니터링되고 관리되는 유통채널 시스템이다. 의사결정책임을 공급사슬 위쪽으로 밀어내고 재고 보충결정을 집중화함으로써, 벤더가 전체 공급사슬이 더욱 경쟁력 있게 도와줄 수 있다. 이 연구의 목적은 한국 제조업자에 의한 VMI 수용에 영향을 미치는 요인들을 탐색하기 위한 것이다. 이 연구는 VMI를 도입하는 데에 대한 부담의 선행요인으로써 IT 준비성, 영업비, 정보공유를 제안한다. 또한 이 연구는 중소규모의 제조자들로부터 설문 결과를 수집하였다. 통계적 결과는 운영비용만이 VMI의 수용에 유의미한 영향을 미쳤다는 것을 나타내었다. 그러나 IT 준비성과 정보 공유는 운영비용에 유의미한 영향을 미치는 것으로 나타났고, 결국 VMI 수용에 간접적인 영향이 있었다. 결론으로 이 연구결과의 학문적, 실무적 시사점도 논의되었다.

• 산업경영시스템학회지
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• 제35권1호
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• pp.66-78
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• 2012

This paper proposes a computation model of the quantity supplied to optimize inventory costs for the fast fashion. The model is based on a forecasting, a store and production capacity, an assortment planning and quick response model for fast fashion retailers, respectively. It is critical to develop a standardized business process and mathematical model to respond market trends and customer requirements in the fast fashion industry. Thus, we define a product supply model that consists of forecasting, assortment plan, store capacity plan based on the visual merchandising, and production capacity plan considering quick response of the fast fashion retailers. For the forecasting, the decomposition method and multiple regression model are applied. In order to optimize inventory costs. A heuristic algorithm for the quantity supplied is designed based on the assortment plan, store capacity plan and production capacity plan. It is shown that the heuristic algorithm produces a feasible solution which outperforms the average inventory cost of a global fast fashion company.