• IE interfaces
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• v.17 no.spc
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• pp.52-61
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• 2004

During the past decades automated storage/retrieval (AS/R) systems have been dominantly implemented in most industrial fields due to their handling efficiency and high utilization of storage space. Such AS/R systems consist of several modules each of which contains two racks and a S/R machine. This paper proposes a design of the hybrid AS/R module which can be adopted without too much initial expenditure by most of small-and-medium sized companies. The hybrid module consists of an AS/R module on the upper floor and a traditional warehouse module on the lower floor. For the AS/R module, analytical expressions of the expected travel times for the S/R machine and the elevator per operation are derived. The expected travel times represent the performance of the module and thus can be used for its economic design.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.04a
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• pp.253-256
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• 2000

In general, Automated Storage/Retrieval Systems (AS/RS ) have racks of equal sized cells to utilize the concept of unit-load. Most of the techniques for the performance estimation of a unit-load AS/RS are a static model or computer simulation. Especially, their models were developed under assumption that the Storage/Retrieval (S/R) machine performs only single command (SC) or dual command (DC). In reality, defending on the operating policy and the status of the system at a particular time, the S/B machine performs a SC or a DC, or becomes .: idle. In order to resolve these weak points, we propose a stochastic model for the performance estimation of unit-load AS/RS by using a single-server queueing model. Expected numbers of waiting storage and retrieval commands are found

• Journal of the Korean Operations Research and Management Science Society
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• v.14 no.1
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• pp.119-130
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• 1989

This paper presents average travel time models automated warehousing system where the stacker crane transports only one pallet at a time with the tchebychev travel, I/O point is located at the cornor of the rack, and items are stored by the class-based storage assignment rule. In this study, the racks are treated as the continuous rectangle in time and a statistical approach was used to develop the models. In order to test the proposed models, average travel times determined by the models are compared with the true values for various rack shapes.

• Nuclear Engineering and Technology
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• v.51 no.3
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• pp.884-893
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• 2019

Spent fuel racks are steel structures used in the storage of the spent fuel removed from the nuclear power reactor. Rack units are submerged in the depths of the spent fuel pool to keep the fuel cool. Their free-standing design isolates their bases from the pool floor reducing structural stresses in case of seismic event. However, these singular features complicate their seismic analysis which involves a transient dynamic response with geometrical nonlinearities and fluid-structure interactions. An accurate estimation of the response is essential to achieve a safe pool layout and a reliable structural design. An analysis methodology based on the hydrodynamic mass concept and implicit integration algorithms was developed ad-hoc, but some dispersion of results still remains. In order to validate the analysis methodology, vibration tests are carried out on a reduced scale mock-up of a 2-rack system. The two rack mockups are submerged in free-standing conditions inside a rigid pool tank loaded with fake fuel assemblies and subjected to accelerations on a unidirectional shaking table. This article compares the experimental data with the numerical outputs of a finite element model built in ANSYS Mechanical. The in-phase motion of both units is highlighted and the water coupling effect is detailed. Results show a good agreement validating the methodology.

• Journal of Korean Institute of Industrial Engineers
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• v.39 no.1
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• pp.55-60
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• 2013

VNA(Very Narrow Aisle) forklift trucks require narrower aisle width than traditional counter-balanced trucks do because only the fork assembly turns in the aisle instead of the entire body of the truck. Substituting the VNA trucks for the existing counter-balanced trucks will result in the significant increase of revenue due to the increased storage capacity in the distribution centers. In this study, we present an economic analysis model for the substitution, in which we present a closed-form equation for the number of racks to stay unmoved, while maximizing the additional storage capacity; and resulting payback period of the substitution. A case study shows the payback period of only 8.1 months, indicating that this substitution is very profitable.

• Steel and Composite Structures
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• v.30 no.5
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• pp.457-469
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• 2019

Steel pallet racking industry has globally used from the industrial revolution and has deeply evolved from hot-rolled profile into cold-formed profile to raise the optimization in engineering field. Nowadays, some studies regarding cold-formed steel profile have been performed, but fewer studies in terms of cold-formed pallet racking specifically in connection due to the semi-rigid behavior by lug-hooked into the upright have been conducted. The objective of this study is to review the related literature on steel storage racking connection behavior.

• Journal of the Korea Furniture Society
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• v.28 no.1
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• pp.47-52
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• 2017

With the rapid economical and technological progress in China, the demand for wine increased tremendously along with the need for wine storage furniture and wine related products. Although demand for furniture increased, consumers' emotional need toward high quality design product has not been met properly. As the quality of people's life improves, they pursue better materials providing them with higher mental satisfaction. To meet the specific demand of Chinese market stated above, the direction of this report is set as to study pattern elements of Chinese traditional lattice and combine them with wine storage furniture design and crafting, which is originated from western culture. By doing that, the study is aimed to suggest a new direction of Chinese modern design and to improve the fundamental notion of Chinese furniture design. Although wine and wine racks are from western world, the wine mini-bar designed in this study stands out for its beauty and taste of eastern culture. It not only fits perfectly to the habits and taste of wine lovers, but also goes very well with fusion style interior design trend in modern China. The furniture carries the charm of eastern cultural tradition and elegance of modern furniture design in one.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.10a
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• pp.251-252
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• 2015

Recently, as warehouses became automated, workers are trying to maximize storage efficiency as well as work efficiency. So, using mobile-rack which has wheels or rails at the bottom and minimizes dead space by removing extra passages between racks is rapidly rising as a notable technology. So, this paper seeks how to manage optimally cryogenic warehouse using mobile-rack. At first, routes of mobile-rack and operation vehicle will be synchronized and storage location will be decided with seasonal demand. After that, it will be simulated considering additional factors.

• Korean Management Science Review
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• v.19 no.1
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• pp.1-12
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• 2002

Performances of common zone with various sizes are examined for possible demand rate variations for an AS/RS. Common zone is a middle area located between the 1st class and the 2nd class to be used by the 1st class Items if the assigned racks are not enough. This area is designed to resolve the rack shortage problem associated with a particular class. In the previous researches, effect of demand rate variation is Ignored since flxed demand rate is assumed. It is found that rack shortage rate is decreased up to 67% of common zone size. However, no difference is found at above 70%. Waiting time tends to be longer with Increased common zone while travel time and throughput are not affected at all with the common zone sloe.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.7
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• pp.2349-2357
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• 2010

This work focuses on the implementation and optimization of the Automated Storage and Retrieval System(AS/RS) which is associated with Logistics Information System(LIS). We survey literature and present a case study for the optimization of Logistics System. In the case study, we examine the adaptation and implementation of AS/RS after we analyzed the processes of the company. Logistics Information System is an important component to keep up with the competitive advantage in the global business environments. The company in the case applies LIS to its efficient physical distribution management. AS/RS leads to some benefits; maximized storage space, increased productivity, reduced labor costs and human error, and improved accuracy. AS/RS is found especially effective when working with narrow aisles and extremely high racks.