• 한국디지털정책학회:학술대회논문집
• /
• 2005.11a
• /
• pp.411-424
• /
• 2005

A large scale automated material handling system (AMHS) is simulated using real industrial input data to analyze its performance so that one can scrutinize the critical factors that affect the AS/RS performance. The factors included in this study are line balancing efficiency, the distance between machines, and cycle time of the machines. The performance of AS/RS is measured in terms of R/M utilities that are latter used to classify the AS/RS structure into three types such as Good, Normal, and Poor. Among the three factors considered in this study, the line balance efficiency within each AS/RS is found as the most critical factor which statistically affect the AS/RS performance.

• Journal of the Korean Wood Science and Technology
• /
• v.24 no.2
• /
• pp.71-80
• /
• 1996

Handling the manufacured goods is the most cost-consuming task in material handling system in wooden furniture industries. Fully automated warehouse for cartoned goods of a furniture manufacturing company was analized to provide plant engineers and managers with some important informations on the utility and profitability of the automated storage and retrieval system(AS/RS). Process-oriented simulation modeling tech-niques were used to describe the system and to propose some alternatives to promote the efficiency of AS/RS. Simulation report could be inter-preted as follows: 1. Warehouse for the furniture goods must be designed in accordance with reliable material handling program and constructed with suitable equipments depending on the specification of packed products. 2. An excess of palletized products induced the indigestion and the inefficiency of AS/RS of the furniture industry and put this high-costly system into the shade. 3. Overcrowded AS/RS of the furniture factories could regain its material handling function by cutting down the deposit of products into the automated warehouse. For this purpose, reducing the regular output and direct delivering the outside products to the destination should be considered as the definite counterplan. And additional operation of conventional handy warehouse was also expected to improve the efficiency of main AS/RS.

• IE interfaces
• /
• v.12 no.2
• /
• pp.237-246
• /
• 1999

The Automated Storage/Retrieval System(AS/RS) is very expensive to be built. But there are few tools available which can be used to design the storage systems optimally considering overall system building costs and constraints. In this paper, we propose a design support system for optimal design of AS/RS which includes different sized cells using expert systems and mathematical models considering customer's demands. The optimization models are to be used to minimize the total cost including building, equipment and operation costs. Expert system technique is utilized for using the experiences of skilled designers. By using the proposed system, AS/RS can be designed accurately, economically and efficiently.

• Journal of Korean Institute of Industrial Engineers
• /
• v.22 no.2
• /
• pp.179-188
• /
• 1996

We study n-class-based storage policy for an automated storage/retrieval system (AS/RS) and derive the closed form expressions of expected travel times under single command cycle. In order to confirm the correctness of the derivations, we consider both discrete and continuous storage racks, and show that the expressions for expected travel times of discrete rack converge to those of continuous one. We also derive the expected travel times when the coordinate locations for storages or retrievals are triangularly distributed and we try to solve class layout problem using the obtained results. Numerical examples are given in case of 3-class-based storage policy.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.20 no.41
• /
• pp.95-102
• /
• 1997

This paper deals with an order picking system in an automated storage and retrieval system(AS/RS). For the order picking system, two fundamental policies, the batching and the picking policies, must be selected. The batching policy determines the manner in which orders are combined for picking in each trip of picking machine. The picking policy determines the sequence of all items in each group of orders. Most of studies for the batching policy doesn't consider dynamic arrivals and due dates of orders. Therefore, we present an batching policy which considers dynamic arrivals and due dates of orders. The presented batching policy is efficient for the automated storage and retrieval system which is connected with a manufacturing system.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.22 no.49
• /
• pp.1-10
• /
• 1999

A cost minimization model for designing AS/RS (Automated Storage/Retrieval Systems) has been developed, whose objective function includes penalty cost caused by the incapability of meeting throughput rate requirements as well as S/R machine cost, storage rack cost, and interface conveyor cost. Since the model is a nonlinear integer programming problem which is very hard to solve with large problem size the problem is divided into four cases according to the ratio of horizontal S/R machine speed to its vertical speed and the existence of the penalty cost. A solution procedure is developed which solves each problem exactly under the different number of S/R machines.

• Journal of Korean Institute of Industrial Engineers
• /
• v.25 no.2
• /
• pp.274-281
• /
• 1999

In this paper, we determine the required storage capacity of a unit-load automated storage/retrieval system(AS/RS) under random storage assignment(RAN) and n-class turnover-based storage assignment(CN) policies. For each of the storage policies, an analytic model to determine the optimal storage capacity of the AS/RS is formulated so that the total cost related to storage space and space shortage is minimized while satisfying a desired service level. A closed form of optimal solutions for the RAN policy is derived from the model. For the CN policy, an optimal storage capacity is shown to be determined by applying the existing iterative search algorithm developed for the full turnover-based storage(FULL) policy. Finally, an application of the approach to the standard economic-order-quantity inventory model is provided.

• Korean Management Science Review
• /
• v.26 no.1
• /
• pp.93-112
• /
• 2009

In this paper, a model is presented to estimate a cycle time for completing an operation in a new type of AS/RS which can handle very heavy loads by separating the mechnisms for vertical and horizontal movements. Considering loading/unloading time between devices, we generalize the previous work, Hu et al. [9], which neglected the transfer time. Through the numerical experiments for various situations, we find that the difference of the cycle times between two models is fairly large and conclude that the transfer time between devices cannot be neglected at all.

• Journal of the KSME
• /
• v.34 no.2
• /
• pp.101-111
• /
• 1994

이 글에서는 무인운반차(AGV: Automated Guided Vehicle), 자동창고 (AS/RS: Automated Storage/Retrieval System), 콘베이어시스템, 바코드시스템 등의 자동물류취급시스템을 응용하여 극단적인 다품종 소량생산체제의 납기단축효과와 가동효율을 어떻게 향상시킬 수 있는지를 저 자들이 직접주도하여 설계 . 설치 . 가동중인 사례를 통하여 실증적으로 밝혀보고자 한다.

• Journal of Korean Institute of Industrial Engineers
• /
• v.14 no.1
• /
• pp.31-42
• /
• 1988

This paper studies class-based turnover assignment rule in terms of the expected travel time in automated storage/retrieval systems (AS/RS). With the rack face not necessarily in square in time, travel time models of two and three-class systems are developed, from which class partition values are determined for single command cycle. Also, the effects of the system parameters such as the rack shape factor and the skewness of the ABC curve are evaluated on the travel time through example problems.