• 경영과학
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• 제33권1호
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• pp.1-16
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• 2016

Drop-shipping is a commonly adopted online-order fulfillment strategy in the Internet age. In this practice, online retailers leverage the fulfillment capabilities of suppliers to fulfill orders. On the other hand, purchase dependence is a frequent phenomenon and is characterized by the purchase of certain items together due to their unknown interior associations. Although this concept has been significantly examined in the marketing field (e.g. market basket analysis), it has largely remained unaddressed in operations management. This paper develops an (R, T) model to address an environment in which unmet demand orders are partially lost and partially backordered when purchase dependence exists. The partial backorders are fulfilled by a drop-shipping option. Through computational analyses, this paper demonstrates the effect of both drop shipping on a partial backordering and purchase dependence. The results shows that more profit can be realized by utilizing a drop-shipping option under purchase dependence.

• 대한기계학회논문집
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• 제18권11호
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• pp.2805-2816
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• 1994

This paper describes dynamic finite element analyses performed to study the dynamic behaviors of a shipping container under the impact onto rigid target due to the accidental fall from the hight of 9 m. Using two and three dimensional techniques, the shipping container which gave the maximum damage, ten different drop orientations are considered ; at intervals of $5^{\circ}$ from $45^{\circ}$ to $90^{\circ}$ According to the present results, the orientation of the shipping container which gave the maximum damage is $85^{\circ}$ from horizontal for oblique drop in the primary impact. In the optimal design of the shipping container, the impact limiter material must be considered importantly because it's proper selection affects the weight and the manufacturing cost of the shipping container. The analysis of the shipping container in this paper demonstrated that the shipping container is structurally sound relative to the regulatory drop test requirements.

• 대한기계학회논문집A
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• 제21권3호
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• pp.457-469
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• 1997

A nuclear spent fuel shipping cask is required by IAEA and domestic regulations to withstand a 9m free drop condition. In this paper, the structural analysis under the 9m side drop condition was performed to understand the dynamic impact behavior and to evaluate the safety of the cask for 7 PWR nuclear spent fuel assemblies. The analysis result was compared with the measured value of the 9m side drop test for the 1/3 scaled-down model and the accuracy of the 3D analysis was confirmed. Analysis in accordance with the diameter of impact limiters for the proto-type cask were performed. Through the analysis, the impact behaviors due to the side drop and the effects dependent on the diameter of impact limiters were grasped. Maximum stress intensities on each part of the cask were respectively calculated by using the stress evaluation program and the structural safety of the cask was finally evaluated in accordance with the regulations.

• 한국전산구조공학회논문집
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• 제18권1호
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• pp.43-49
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• 2005

방사선물질을 수송하기 위한 용기는 가상 사고조건에서도 안전해야만 한다. 운반용기 설계요구조건은 실험 및 유한요소 해석을 통해 구조적 건전성을 확보하여야 한다. 최근에는 실험보다 유한요소해석을 이용한 방법이 상대적으로 비용이 적기 때문에 주로 사용된다. 그러나 기계적인 반응이 복잡하기 때문에 프로그램을 적용하는 사용자의 방법에 의해 결과가 결정되고 해석하는 동안 여러가지 문제를 발생시킬 수 있다. 본 논문에서, 유한요소해석은 LS-DYNA3D와 ABAQUS/Explicit을 이용하여 운반용기의 9m 자유낙하충격실험에 대한 해석기술과 여러가지 손상을 갖는 경우를 발견하기 위해 연구하였다. 운반용기의 각각의 경우를 비교하고 사용후 핵연료 운반용기의 낙하 실험에 대해서 신뢰할 수 있는 비교적 간단한 해석 기술을 제안하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 II
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• pp.766-771
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• 2001

The package used to transport radioactive materials, which is called by cask, must be safe under normal and hypothetical accident conditions. These requirements for the cask design must be verified through test or finite element analysis. Since the cost for FE analysis is less than one for test. the verification by FE analysis is mainly used. But due to the complexity of mechanical behaviors. the results depends on how users apply the codes and it can cause severe errors during analysis. In this paper, finite element analysis is carried out for the 9 meters free drop and the puncture condition of the hypothetical accident conditions using LS-DYNA3D and ABAQUS/Explicit. We have investigated the analyzing technique for the free drop impact test of the cask and found several vulnerable cases to errors. The analyzed results were compared with each other. We have suggested a reliable and relatively simple analysis technique for the drop test of spent nuclear fuel casks.

• 한국소음진동공학회논문집
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• 제19권4호
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• pp.370-377
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• 2009

A simple preliminary analysis is often useful to check a validity of design alternatives before the detailed analysis phase in the viewpoint of efficiency. This paper describes a preliminary analysis procedure for the selection among basket design candidates for the spent fuel shipping cask of Korean standard nuclear power plant. As the cask should maintain the structural integrity in hypothetical accident condition, the case of 9 m drop is significantly considered as the worst scenario among the accident conditions in structural design viewpoint in this paper. As basket design options, totally four different types are considered and analyzed in the point of structural integrity at drop impact and weldability for fabrication. As a result, an insertion round plate type with densely spaced supports turns out to be the best in both of the viewpoints, though the weld plate type shows a bit more design margin.

• Journal of Electrical Engineering and Technology
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• 제8권4호
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• pp.737-743
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• 2013

The small-scaled onsite generators such as photovoltaic power, wind power, biomass and fuel cell belong to decarbonization techniques. In general, these generators tend to be connected to utility systems, and they are called distributed generations (DGs) compared with conventional centralized power plants. However, DGs may impact on stabilization of utility systems, which gets utility into trouble. In order to reduce utility's burdens (e.g., investment for facilities reinforcement) and accelerate DG introduction, the advanced operation algorithms under the existing utility systems are urgently needed. This paper presents the advanced voltage regulation method in power systems since the sending voltage of voltage regulators has been played a decisive role restricting maximum installable DG capacity (MaxC_DG). For the proposed voltage regulation method, the difference from existing voltage regulation method is explained and the detailed concept is introduced in this paper. MaxC_DG estimation through case studies based on Korean model network verifies the superiority of the proposed method.

• 방사성폐기물학회지
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• 제14권2호
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• pp.149-156
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• 2016

저장조에 위치한 사용후핵연료는 가혹한 원자로 조건에 의해 구조적 건전성이 와해되므로 외력에 취약하다. 따라서 운반 및 취급 중 사고 상황이 고려되어야 한다. 극단적인 경우, 핵연료 취급 중 사고로 인해 핵연료 저장조에서 핵연료집합체 낙하가 발생할 수 있다. 이러한 사고 상황 하에서 연료봉 파손 등을 평가하기 위해서 수조에 충돌할 때 발생하는 충돌력을 분석할 필요가 있다. 이는 핵연료가 수조 바닥에 충돌할 때의 속도를 입력으로 하여 평가될 수 있다. 연료봉이 핵연료 중량 및 부피의 대부분을 차지하고 있으므로, 연료봉 다발은 수중 항력을 예측하는데 중요한 역할을 한다고 볼 수 있다. 본 연구에서는 $3{\times}3$ 의 짧은 연료봉 다발을 모델로 사용하여 수중에서 낙하할 때 받는 수력을 계산하였고, 이를 전산모사와의 비교를 통하여 검증하였다. 본 방법론을 사용후핵연료 건전성 평가에 적용할 수 있을 것으로 기대된다.

• 문화기술의 융합
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• 제9권1호
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• pp.61-68
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• 2023

글로벌 저성장 시대가 지속되고 있는 현 시점에, Customer to Customer(C2C) 시장이 점차 확대되고 있으며, 앞으로의 성장 가능성도 증가하고 있다. 이에 따라 본 연구에서는 C2C시장 내, 태블릿PC 중고제품의 판매에서 가격에 영향을 미치는 요인을 파악하고자 한다. 이를 위해 일본 최대 C2C커뮤니티 마켓플레이스 플랫폼인 Mercari가 제공한 태블릿PC 중고거래 데이터를 분석하였다. 연구방법으로는 선형회귀 분석을 사용하였으며, 중고 거래가의 로그 변환을 종속변수로 하였고, 이에 영향을 주는 독립변수는 다중공선성 문제와 본페르니 수정을 통해 제품 상태, 제조사, ROM용량, RAM용량, 액세서리 포함 유무, 잠긴 상태를 선정하였다. 분석 결과, 제품상태 등급이 낮고 ROM과RAM용량이 클수록, Apple사의 태블릿PC 제품일 때, 액세서리가 있을 때, 중고 태블릿PC의 로그 가격이 높아지고, 태블릿PC가 잠겨있는 상태일 때는 그렇지 않을 때보다 로그 가격이 낮아진다는 것을 파악하였다. 로그 가격에 가장큰 영향력을 주는 변수는 RAM용량인 것을 알 수 있었다. 본 연구를 통해 판매자와 구매자의 경계가 불투명한 C2C 시장에서 중고 태블릿PC의 적절한 수준의 가격을 제공해 판매자와 구매자 모두에게 도움을 줄 수 있다.

• 마이크로전자및패키징학회지
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• 제11권1호
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• pp.43-47
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• 2004

We have been using Moisture Barrier Bags for dry packing of semiconductor packages to prevent moisture from absorbing during shipping. Moisture barrier bag material is required to be waterproof, vapor proof and offer superior ESD (Electro-static discharge) and EMI shielding. Also, the bag should be formed easily to the shape of products for vacuum packing while providing excellent puncture resistance and offer very low gas ＆ moisture permeation. There are some problems like pinholes and punctured bags after sealing and before the surface mount process. This failure may easily result in package pop corn crack during board mounting. The bags should be developed to meet the requirements of excellent electrical and physical properties by means of optimization of their raw material composition and their thickness. This study investigates the performance of moisture barrier bags by characterization of their mechanical endurance, tensile strength and through thermal analysis. By this study, we arrived at a robust material composition (polyester/Aluminate) for better packing.