• Industrial Engineering and Management Systems
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• 제8권2호
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• pp.80-92
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• 2009

This paper addresses the inventory rationing issue embedded in the regional supply chain inventory replenishment problem (RSIRP). The concerned supply chain, which was fed by the national supply chain, consisted of a single warehouse distributing a single product to multiple stores (M-stores) with independent and normally distributed customer demand. It was assumed that the supply chain operated under the order-up-to level inventory replenishment system and had only one truck at the regional warehouse. The truck could make one replenishment trip to one store per period (a round trip per period). Based on current inventories and the vehicle constraint, the warehouse must make two decisions in each period: which store in the region to replenish and what was the replenishment quantity? The objective was to position inventories so as to minimize lost sales in the region. The warehouse inventory was replenished in every fixed-interval from a source outside the region, but the store inventory could be replenished daily. The truck destination (store) in each period was selected based on its maximum expected shortage. The replenishment quantity was then determined based on the predetermined order-up-to level system. In case of insufficient warehouse inventories to fulfill all projected store demands, an inventory rationing rule must be applied. In this paper, a new inventory rationing rule named Expected Cost Minimization (ECM) was proposed based on the practical purpose. The numerical results based on real data from a selective industry show that its performance was better and more robust than the current practice and other sharing rules in the existing literature.

• 한국시뮬레이션학회논문지
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• 제24권1호
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• pp.1-8
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• 2015

본 연구는 다양한 공급망 내 재고관리 방법 중 최적의 방법을 찾아내는 것을 목적으로 하고 있다. 비교대상 재고관리 방법은 Min-Max, 정기, 정량, 목표재고관리 방법으로 각 제품별 리드타임과 수요를 달리하여 구성하였다. 또한 공급사슬 망의 단계가 2단계인 경우와 3단계인 경우를 구분하여 공금망 단계를 줄였을 경우의 결과를 분석한다. 시뮬레이션 모형은 8개의 시나리오로 나뉘며, 각 시나리오는 주문방식과 단계로 구분할 수 있다. 시뮬레이션을 위한 입력 자료는 기존의 선행연구 결과와 실제데이터를 토대로 하였다. 시뮬레이션의 평가는 매출액, 총판매건수, 총배송비, 총결품량, 결품횟수, 결품손실금, 평균 재고량, 재고관리비, 순이익으로 실시한다. 시뮬레이션 결과 목표재고관리 방법이 가장 우수하게 나타났으며, 목표재고관리 시스템은 기존의 재고관리 방법을 사용한 시나리오보다 순이익 및 재고 등의 측면에서 우수한 결과를 나타냈다. 또한 기존의 공급사슬에서 한 단계 공급망을 줄였을 경우 수익이 증가하는 것을 확인할 수 있었다. 본 연구 결과는 목표재고관리 시스템을 추가적으로 고려하고 있다는 것과 공급사슬의 단계를 줄일 수 있는 개선 방안을 논의했다는 것에 의의를 둘 수 있다.

• 제어로봇시스템학회논문지
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• 제17권9호
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• pp.932-940
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• 2011

This paper presents an integrated analysis of supply chain and financing decisions of multi-national corporation. We construct a model in which multiple currency storage units are installed to manage the currency flows associated with multi-national supply chain activities such as raw material procurement, process operation, inventory control, transportation and finished product sales. Core contribution of this study is to quantitatively investigate the influence of macroscopic economic factors such as exchange rates and taxes on operational decisions. The supply chain is modeled by the Process-Storage Network with recycle streams. The objective function of the optimization is minimizing the opportunity costs of annualized capital investments and currency/material inventories minus the benefit to stockholders interpreted by home currency. The major constraints of the optimization are that the material and currency storage units must not be depleted. A production and inventory analysis formulation, the periodic square wave (PSW) model, provides useful expressions for the upper/lower bounds and average levels of the currency and material inventory holdups. The expressions for the Kuhn-Tucker conditions of the optimization problem are reduced to a subproblem and analytical lot sizing equations. The procurement, production, transportation and financial transaction lot sizes can be determined by analytical expressions after the average flow rates are already known. We show that, when corporate income tax is taken into consideration, the optimal production lot and storage sizes are smaller than is the case when such factors are not considered typically by 20 %.

• 감성과학
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• 제20권1호
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• pp.95-104
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• 2017

분노반응검사(Evans & Stangelang, 1971)는 분노를 유발하는 자극의 관점에서 분노수준을 평가하는 도구이다. 그러나 이는 고령자를 대상으로 사용하기에는 문항수가 너무 많아 적은 수의 문항으로 구성된 분노반응검사가 필요하다. 본 연구의 목적은 신뢰성이 높고 타당한 단축형 분노반응검사를 제작하는 것이다. 연구 1에서는 60세 이상의 고령자들에게 76문항으로 구성된 분노반응검사를 실시하였으며, 검사이론에 기초하여 76개의 문항들 중에서 10개의 문항을 추출하여 단축형 분노반응검사를 제작하였다. 연구 2에서는 60세 이상의 고령자들로 구성된 또 다른 표본을 대상으로 단축형 분노반응검사와 타당도 확인을 위한 검사들을 함께 실시하여 신뢰도와 타당도를 평가하였다. 노인용 단축형 분노반응검사의 Cronbach 는 .79로 양호한 수준의 신되도를 보였다. 노인용 단축형 분노반응검사는 특성분노를 반영하는 검사이므로, 특성분노를 측정하는 검사점수와 상관이 높아야하고, 분노의 다른 측면을 반영하는 점수와는 낮은 상관을 보여야 타당하다. 노인용 단축형 분노반응검사 점수는 상태-특성 표현 척도의 특성분노 점수와 .60이상의 높은 상관을 보였으며, 분노표출 점수와 .39의 상관을 보였고, 적대감 점수와 .41의 상관을 보였다. 결론적으로, 본 연구에서 제작한 단축형 분노반응검사는 신뢰할 수 있고 타당한 검사인 것으로 나타났다.

• 산업경영시스템학회지
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• 제32권2호
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• pp.57-65
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• 2009

In continuous review inventory model, (${\varrho}$, ${\gamma}$) system, order quantity(${\varrho}$) and reorder point(${\gamma}$) should be determined to calculate inventory-related cost that consists of setup, holding, and penalty costs. The procedure to obtain the exact value of ${\varrho}$ and ${\gamma}$ is complex. In this paper, a regression analysis is proposed to get the approximate inventory-related cost without the determination of ${\varrho}$ and ${\gamma}$ in the case that the standard deviation(${\sigma}$) of the lead time demand is small or that the mean(${\mu}$) of the lead time demand is proportional to ${\sigma}$. To save inventory-related cost, central warehouses with (${\varrho}$, ${\gamma}$) system can be built. Central warehouse can provide some stores with products with the consideration of the tradeoff between inventory-related cost and transportation cost. The number and the location of central warehouses to cover all the stores are determined by a regression-based approach. The performance of the proposed approach is tested by using some computational experiments.

• 산업공학
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• 제19권1호
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• pp.78-85
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• 2006

A centralized inventory system provides a number of stores with cost reduction, information sharing. In this paper, transportation costs are included in the inventory model. To build centralized warehouses, two things should be considered: how many warehouses are required and where these are located. The objective of this paper is to develop efficient heuristics to determine the location and the number of central warehouses by minimizing total costs. Throughout some computational experiments, the results of the heuristics are compared with an optimal solution.

• 한국축산시설환경학회지
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• 제20권4호
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• pp.139-146
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• 2014

This research was conducted to examine the temporal methane ($CH_4$) and nitrous oxide ($N_2O$) emission trends in livestock agriculture from year 1990 to 2011 with Tier 1 national greenhouse gas (GHG) inventory reporting method, which was related to efforts of decreasing GHG emissions and to achievement of voluntary GHG mitigation target. Methane emissions from enteric fermentation were calculated with default $CH_4$ emission factors of IPCC. Methane and $N_2O$ emissions from manure treatment processes were calculated with Tier 1 and mixture of Tier 1 and Tier 2 including $N_2O$ emission factors of manure treatment systems and nitrogen excretion rate of livestock, respectively. According to 2013 National GHG Inventory Monitoring, Reporting, and Verification report, GHG emission fluctuations from enteric fermentation and manure treatment processes were similarto livestock head fluctuation. GHG emissions from enteric fermentation were mainly affected by beef cattle including Hanwoo, while manure treatment processes were affected by various livestock.

• 산업경영시스템학회지
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• 제38권4호
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• pp.109-116
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• 2015

This paper is concerned with the single vendor single buyer integrated production inventory problem. To make this problem more practical, space restriction and lead time proportional to lot size are considered. Since the space for the inventory is limited in most practical inventory system, the space restriction for the inventory of a vendor and a buyer is considered. As product's quantity to be manufactured by the vendor is increased, the lead time for the order is usually increased. Therefore, lead time for the product is proportional to the order quantity by the buyer. Demand is assumed to be stochastic and the continuous review inventory policy is used by the buyer. If the buyer places an order, then the vendor will start to manufacture products and the products will be transferred to the buyer with equal shipments many times. The mathematical formulation with space restriction for the inventory of a vendor and a buyer is suggested in this paper. This problem is constrained nonlinear integer programming problem. Order quantity, reorder points for the buyer, and the number of shipments are required to be determined. A Lagrangian relaxation approach, a popular solution method for constrained problem, is developed to find lower bound of this problem. Since a Lagrangian relaxation approach cannot guarantee the feasible solution, the solution method based on the Lagrangian relaxation approach is proposed to provide with a good feasible solution. Total costs by the proposed method are pretty close to those by the Lagrangian relaxation approach. Sensitivity analysis for space restriction for the vendor and the buyer is done to figure out the relationships between parameters.

• 대한토목학회논문집
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• 제43권1호
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• pp.79-89
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• 2023

많은 자재의 재고를 위해서는 넓은 야적공간이 요구되며, 보관기간이 길어짐에 따라 유지비용이 증가하고, 자재를 건설 현장에 적치할 경우 이동 불편과 작업공간 부족으로 안전사고가 우려된다. 반면 자재를 확보하지 못한 건설 현장은 재고가 부족하여 설계변동 등의 예상치 못한 수요 발생 시 대응이 어렵고 공기 지연 발생과 잦은 주문으로 인해 주문 비용이 증가할 수 있다. 이렇듯 적정재고량의 확보는 중요한 요소임에도 불구하고 건설 현장의 자재관리는 많은 경우에 현장관리자의 경험에 의존해 운영되는 사례가 많으므로 현장의 공정 조건이 반영된 합리적인 자재 재고관리 방안이 필요하다. 본 연구는 선후행 공정 현황, 야적장 크기, 자재 운반비, 주문 시기, 주문량 등과 같은 현장 조건을 반영하여 경제성 있는 자재관리 방법론을 제안한다. 이를 위해 공정별 여유시간, 야적장의 크기, 주문량을 주요 변수로 하여 공정표에서 부속공정을 조정하면서 적정재고량을 설정하고, 이 과정에 유전알고리즘을 적용하여 최적화된 주문 시점 및 주문량을 제시한다. 결과를 통해 도출된 운반비는 적합도 지표로 설정하고 사례적용을 통한 재고관리의 효율성을 검증한다.

• 동의신경정신과학회지
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• 제21권4호
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• pp.187-206
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• 2010

Objectives : This study was designed to report the effect of korean traditional treatment and person-centered counseling for poststroke depression Methods : We treated two patients who scored 37 point and 32 point at Beck's depression inventory each, and 23 point and 22 point at Hamilton rating scale for depression each by korean traditional treatment and person-centered counseling, Results : After treatment, the clinical symptoms were improved and Beck's depression inventory, Hamilton rating scale for depression score were decreased, Conclusions : The result suggest that korean traditional treatment and person-centered counseling is effective in patients with poststroke depression.