• Asia pacific journal of information systems
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• 제14권3호
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• pp.169-187
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• 2004

Self-maintainability of data warehouse(DW) views is an ability to maintain the DW views without requiring an access to (i) any underlying databases or (ii) any information beyond the DW views and the delta of the databases. With our proposed method, DW views can be updated by using only the old views and the differential files such as different files, referential integrity differential files, linked differential files, and backward-linked differential files that keep the truly relevant tuples in the delta. This method avoids accessing the underlying databases in that the method achieves self-maintainability even in preparing auxiliary information. We showed that out method can be applicable to the DW views that contain joins over relations in a star schema, a snowflake schema, or a galaxy schema.

• 한국경영과학회지
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• 제31권3호
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• pp.11-25
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• 2006

Space may be a scarce resource in manufacturing shops, warehouses, freight terminals, and container terminals. This Paper discusses how to locate temporary storage Inventories In limited storage areas. A typical inventory is delivered from the location of the preceding process to the storage area and stored In the storage area during the certain period of time. And it may be relocated from the storage position to another. Finally. it is delivered from the final storage area to the location of the next process. Because this logistic process for an inventory requires handling activities, transportation activities, and storage spaces, the limitation in capacities of handling equipment, transportation equipment, and storage space must be considered when allocating spaces to the inventory. This problem Is modeled as a multicommodity minimal cost flow problem. And a heuristic algorithm for the Problem is proposed. Numerical experiments are presented to validate the mathematical model and the heuristic algorithm.

• 산업공학
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• 제15권4호
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• pp.452-459
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• 2002

The volume of B2C products rapidly increases according to the activation of the electronic commerce. Small and medium electronic commerce companies request the establishment of Parcel Warehouse &Distribution Center(PWDC) that is invested by the post office. This paper presents an economic evaluation method for PWDC from the perspectives fo PWDC and the post office. Two types of warehouses are considered as alternatives for PWDC. One is the conventional warehouse, and the other is the automamic warehouse that is characterized by AS/RS and automatic dispenser system. A benefit/cost analysis method is used to evaluate PWDC since it has the property of public enterprise. A PWDC which will be located in Seoul and adjacent to a concentrated post office is selected as a case study to illustrate the procedure of economic analysis.

• 한국안전학회지
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• 제14권4호
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• pp.192-198
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• 1999

Work-related musculoskeletal disorders constitute a major source of employee disability and lost wages. Cumulative Trauma Disorders(CTD) refers to a category of physical conditions which result from chronic musculoskeletal injury. Assessment of CTD risk in industry at early stage allows for early control, a safe environment, and a healthier workforce. In this study, the physical load of the shipping work in the cold storage warehouse were especially investigated. Employees were working with almost unnatural posture in a very restricted work space. The questionnaire and biomechanical analysis were used to evaluate the physical load. Results from analyses showed that they were sufficiently exposed to CTD due to repetition and unnatural posture. Based on the analysis, ways for improving working conditions are proposed. The analysis and proposals in this paper will serve as a basic tool for designing/redesigning working environment such as improvement of tools and equipments, design of times for work/rest cycle.

• 대한산업공학회지
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• 제24권1호
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• pp.137-144
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• 1998

Block stacking, which involves the storage of unit loads in stacks within storage rows, is typically used in traditional warehouses to achieve a high space utilization at a low investment cost. In this paper, assuming that the demand size from a customer is an i.i.d. random variable, we develop a probabilistic block stacking storage model and its algorithm for a singles product, which minimizes the time-overage floor space requirement under an (s, S) inventory policy and the violation of the FIFO lot rotation rule only in a single partially-occupied row.

• 대한산업공학회지
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• 제30권4호
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• pp.294-300
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• 2004

This paper considers a trade-off effect between in-house storage space and leased storage space in generic warehouses operated under a randomized storage assignment policy. The amount of in-house storage space is determined based on the law of large numbers satisfying a given service level of protection against space shortages. Excess space requirement is assumed to be met via leased storage space. A new analytic model is formulated for determining the excess space such that the total cost of storage space is minimized. Finally, computational results are provided for the systems where the standard economic-order-quantity inventory model is used for all items.

• 한국산업융합학회 논문집
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• 제11권2호
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• pp.93-98
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• 2008

Steel fibre reinforced concrete (SFRC) were considered a new technology for the construction industry. However today this technology has found wider acceptance among the construction industry. Currently, steel fibres are used in varied segments in many application areas across different segments in the construction industry, especially in tunneling, airports, warehouses, etc. Time and safety are the main factors are among the various advantages which renders steel fibres superior to the competing product. For fibers reinforcing, The maximum load carrying capacity is controlled by fibers pulling out of the composite because fiber reinforcing does not have a deformed surface like larger steel reinforcing bars. The study demonstrated that above concept is applicable and effective in concrete structure by analytical study. The analytical result appears that SFRP have the potential to significantly increase the strength of existing concrete structures, while at the same time dramatically improving their fracture energy characteristics.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2003년도 가을 학술발표논문집 Vol.30 No.2 (2)
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• pp.46-48
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• 2003

최근 시공간 데이타에 대한 OLAP연산 효율을 증가시키기 위한 여러 가지 연구들이 행하여지고 있다. 이들 연구의 대부분은 다중트리구조에 기반하고 있다. 다중트리구조는 공간차원을 색인하기 위한 하나의 R-tree와 시간차원을 색인하기 위한 다수의 B-tree로 이루어져 있다. 하지만, 이러한 다중트리구조는 높은 유지비용과 불충분한 질의 처리 효율로 인해 현실적으로 시공간 OLAP연산에 적용하기에는 어려운 점이 있다. 본 논문에서는 이러한 문제를 근본적으로 개선하기 위한 접근 방법으로서 힐버트큐브(Hilbert Cube, H-Cube)를 제안하고 있다. H-Cube는 집계질의(aggregation query) 처리 효율을 높이기 위해 힐버트 곡선을 이용하여 셀들에게 완전순서(total-order)를 부여하고 있으며, 아울러 전통적인 누적합(prefix-sum) 기법을 함께 적용하고 있다. H-Cube는 적응적이며, 완전순서화되어 있으며, 또한 누적합을 이용한 셀 기반의 색인구조이다. 본 논문에서는 H-Cube의 성능 평가를 위해서 다양한 실험을 하였으며, 그 결과로서 유지비용과 질의 처리 효율성면 모두에서 다중트리구조보다 높은 성능 향상이 있음을 보인다.

• 한국경영과학회지
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• 제11권1호
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• pp.44-50
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• 1986

In this paper, we find optimal policy for the (Q, r) inventory model under the lead time uncertainty. The (Q, r) inventory model is such that the fixed order quantity Q is placed whenever the level of on hand stock reaches the reorder point r. We first develop the single level inventory model as the basis for the analysis multi-level distribution systems. The functional problem is to determine when and how much to order in order to minimize the expected total cost per unit time, which includes the set up, inventory holding and inventory shortage cost. The model, then, is extended to the multi-level distribution system consisting of the factory, warehouses and retailers. In this case, we also find an optimal policy which minimizes the total cost of the contralized multi-level distribution system.

• 한국연초학회지
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• 제26권1호
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• pp.13-16
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• 2004

This study was designed to investigate population dynamics of cigarette beetle, Lasioderma serricorne F.(Coleoptera, Anobiidae), at differential house types in Korea. In hot season, July 24 to August 24, cigarette beetle adults were captured by sex-pheromon-trap at all house types which were located in Wonjoo, Shintanjin and Suwon area. Cigarette beetle adults were captured only at apartments where located at same area by sex-pheromon-trap during overwintering period in Korea. No relation was detected between a limit of the distribution of cigarette beetle, L. serricorne F. and the distance from tobacco storage warehouses to houses in Korea.