• The Journal of Korean Institute for Practical Engineering Education
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• v.4 no.1
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• pp.80-85
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• 2012

The importance of warehouse is increasing since the role of warehouse in modern industry is changing from concept of storage to concept of circulation which facilitates purchasing, production, storage and distribution activities by induction of information system. In this study, a program is developed using C# for evaluating efficiency of automated storage and retrieval system(AS/RS). A simulation work is done for eight operating schemes under the combination of three conditions, which are storing method, the shape of automatic warehouse and the sequence of command performs, and the moving distance of stacker crane is calculated using the same gateway data. Using this program, the optimal operating scheme can be proposed based on the analyzed results of simulation. This progrm shows the effectiveness and applicability through the simulation work and can be utilized for courses which are related to factory facilities.

• Journal of the Korean Operations Research and Management Science Society
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• v.13 no.1
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• pp.39-50
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• 1988

The warehousing of inventories is an enormous expense to industries worldwide, and yet there are few available that can be used to design rack storage systems while considering overall system costs. The primary objective of this paper is the development of an overall ware hous storage system costs model to aid a warehous planner in the design of automated warehouse systems. A simulation model and statistical estimation procedures are used to determine the maximum inventory levels accumulated in the receiving, storage, and shipping areas. The overall cost model is developed to determine the required total land, the initial investment fund, the number of pieces of handling equipment, and the storage rack configuration for the main storage area. A numerical example is then presented to demonstrate the application of the overall system cost model developed in this paper.

• Journal of Korean Society for Quality Management
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• v.16 no.2
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• pp.99-110
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• 1988

This study is concerned with a design algorithm to minimize the investment as well as maximize the throughput in automated warehouse system. A simulation model is designed and a solution methodology is proposed. The experiment, are conducted for the cases with 100, 90, 80, 70, 60, 50 and 0 % dual command policies in terms of the important factors such as the crane velocity, the height of system and the rack utilization. The results indicate that the throughput is slightly decreased when the ratio of dual command is decreased and the other characteristics however are not affected. The result also shows that the optimal rack should be designed for a crane to take the same amount of travel time for horizontal and vertical movement.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.12B
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• pp.1686-1697
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• 2011

This paper aims to build up a RFID-automated cargo movement system in an air-cargo warehouse. In our research, we do the spectrum measurements compliant with the RFID frequency bands to observe the interferences from legacy systems in the air-cargo warehouse. To overcome the dense-reader mode (DRM) problem, we apply three novel approaches, which are the periodic transmit of a reader, the Visible RFID reader & tag, and the sensor-based RFID system. Moreover, for the tag collision issue, we implement the Adaptive Adjustable Framed Q(AAFQ) algorithm, and the demonstration on RFID tag anti-collision algorithms show that the AAFQ algorithm has highly desirable tag anti-collision performance compared to any other commercially available solutions.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.23 no.5
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• pp.505-511
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• 2014

The functional role of warehouses in modern industry is changing from an established concept of storage to a concept of circulation. The target of this study is to improve the stacker crane's efficiency for the internal operations of the Automated Storage and Retrieval System (AS/RS). Eight operating schemes are proposed under the combination of three conditions, namely, the storing method, the layout type, and the sequence of command execution. The moving distance of the stacker crane is calculated using the same gateway data through a simulation based on a C# program. The optimal operating scheme is proposed based on the analyzed simulation results. In conclusion, the combination of conditions of random storage, two-way type warehouse, and dual command execution elicits optimum results in travel efficiency for the stacker crane.

• Journal of the Korean Institute of Telematics and Electronics
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• v.24 no.2
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• pp.292-300
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• 1987

This paper, realizes the design of the sequential controller of a reinforced warehousing-delivery and unmanned transportation system for automated warehouse system. The system is composed of ware housing delivery adn transportation system using two unmanned vehicles with hierachical structure. It is described by GRAFCET and realized by programmed logic with microprocessor. Being described by GRAFCET, the system is able to divide it into subsystems and to synchronize them. Defining the concept of program module, one can easily program the system with the microprocessor instruction language.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.16 no.27
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• pp.73-82
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• 1993

In this paper, We determine the expected travel time for several forks Storage/Retrieval machine which is allowed multiple stops in aisle. When throughput is increased, We propose adding to fork number of each S/R machine rather than adding to number of S/R machine, We also describe such a model which determines the optimal number of each several forks S/R machine subject to constraints on the hourly throughput and warehouse dimensions. Numerical example is presented to compare warehouse shapes against each single fork, twin forks, triple forks S/R machine for various throughput values.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.34 no.1
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• pp.1-8
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• 2011

Controlling industrial vehicle operated by human in warehouse was not simple since the information transfer for controlling the vehicle was not easy. However, as the technology for the WMS (Warehouse Management System) has been advanced and the PDA (Personal Digital Assistant) has come into wide use in a workplace, the control of man-operated vehicle became less difficult as do to AGVS (Automated Guided Vehicle System). This study examines the ways to improve the efficiency of warehouse operation through introducing rule of task assignment for the vehicles, particularly forklift. This study, basically, refer to AGV operation policy because a great number of studies for AGV dispatching rule have been done and the mechanism for the controlling vehicles is very similar. The workers in field prefer to simple dispatching rules such as Shortest Retrieval Time First (SRTF), Shortest Travel Time First (STTF), and Longest Waiting Time First (LWTF). However, these rules have potential disadvantage. Thus, several rules made up by combining rules mentioned above are introduced and these new rules use threshold value or evaluation formula. The effectiveness of these new rules are tested by simulation and the results are compared. This study proposes favorable dispatching rules for forklift in warehouse for the efficiency of the vehicle operation and stability of service level.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2021.11a
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• pp.101-103
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• 2021

With the rapid increase in the quantity of goods transported worldwide, companies are now started to show great interest in unmanned automated warehouses along with related research and development due to the increase of warehouse efficiency and reduction warehouse manpower. In a number of small warehouses, shuttle rack-based layouts that can handle inventory flow flexibly. However, the shuttle rack-based logistics center does not operate in case of emergency situations (faults, power outages, etc.), which seriously affects the efficiency and inventory management of the entire logistics center. Accordingly, in shuttle rack-based logistics center, we have classified various shuttle passages and RTV passages by layout and have analyzed its characteristics and types, along with derived reliability for each layout. The loading rate was also derived differently according to the number of passages, and have compared and analyzed reliability and loading rate for each layout.

• Journal of the Korean Operations Research and Management Science Society
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• v.13 no.2
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• pp.34-46
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• 1988

This paper deals with design problem of unit load automated storage/retrieval systems (AS/RS). We propose an optimal design model in which the investment and maintenance costs of AS/RS, operating under dual command model is minimized over a time horizon satisfying the warehouse dimensional constraints. The model is formulated as an integer nonlinear program and an algorithm is proposed to find an optimum solution. The valididty of the solution algorithm is illustrated through an example.