• Title/Summary/Keyword: Production Lead Time

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An Inventory Problem with Lead Time Proportional to Lot Size and Space Constraint (로트크기에 비례하는 리드타임과 공간 제약을 고려한 재고관리 정책)

  • Lee, Dongju
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.38 no.4
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    • pp.109-116
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    • 2015
  • This paper is concerned with the single vendor single buyer integrated production inventory problem. To make this problem more practical, space restriction and lead time proportional to lot size are considered. Since the space for the inventory is limited in most practical inventory system, the space restriction for the inventory of a vendor and a buyer is considered. As product's quantity to be manufactured by the vendor is increased, the lead time for the order is usually increased. Therefore, lead time for the product is proportional to the order quantity by the buyer. Demand is assumed to be stochastic and the continuous review inventory policy is used by the buyer. If the buyer places an order, then the vendor will start to manufacture products and the products will be transferred to the buyer with equal shipments many times. The mathematical formulation with space restriction for the inventory of a vendor and a buyer is suggested in this paper. This problem is constrained nonlinear integer programming problem. Order quantity, reorder points for the buyer, and the number of shipments are required to be determined. A Lagrangian relaxation approach, a popular solution method for constrained problem, is developed to find lower bound of this problem. Since a Lagrangian relaxation approach cannot guarantee the feasible solution, the solution method based on the Lagrangian relaxation approach is proposed to provide with a good feasible solution. Total costs by the proposed method are pretty close to those by the Lagrangian relaxation approach. Sensitivity analysis for space restriction for the vendor and the buyer is done to figure out the relationships between parameters.

Adsorption Properties and Production of Biosorbent from Bacillus sp. SK31 (Bacillus sp. SK3l의 생물흡착제 흡착특성 및 생산)

  • 서현호;김형갑
    • Journal of Korea Soil Environment Society
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    • v.4 no.2
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    • pp.33-43
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    • 1999
  • A strain (designated SK3l) which produces an excellent adsorption substance was isolated from soil samples and identified as Bacillus specied. The major adsorption substance (biosorbent SK3l) produced by Bacillus sp. SK31 was purified by ethanol precipitation and cetylpyridinium (CPC) precipitation. The adsorption charactics of zinc and lead ions on bioadsorbent SK3l were investigated. The equilibrium isotherms showed that bioadsorbent SK3l took up zinc and lead from aqueous solutions to the extent of about 52 mg/g and 112 mg/g. respectively. The culture conditions at the flask level of Bacillus sp. SK3l were investigated for the production of polysaccharide bioadsorbent, SK3l. The optimum pH and temperature for sorbent production were 7.5 and $30^{\circ}C$, respectively. The important carbon and nitrogen sources for sorbent formation were glucose and ammonium nitrate, respectively. In the optimized medium, sorbent production was improved three folds in comparison with the basal medium. In the jar fermenter, the highest sorbent production was obtained at 60 h cu1tivation time and the amount of biosorbent SK3l at that time was 9.2 g/$m\ell$.

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On the economic formation of machine cell-part family (경제적인 기계셀-부품군 형성 방법에 관한 연구)

  • 김진용
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.16 no.28
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    • pp.203-209
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    • 1993
  • In Factory Automation environments such as FMS, the formation of machine-part based on GT should be considered. The purpose of this study is to develop a economic heuristic algorithm which considers various elements such as unit processing time, subcontract cost, and functional operation cost, machine processing capacity etc. When this proposed approach is applied to the real situation expected benefits are as follows: the reduction of production lead time work in process, labor force, tooling, rework and scrap, setup time, order time delivery, and paper work, etc.

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A Study on the Motion Analysis and Lead-Filter Design for High Speed/Accuracy Movement of Gantry Robot (갠트리 로봇의 고속/고정밀 이송을 위한 모션분석 및 앞섬필터 설계)

  • Kim, Jin-Dae;Cho, Che-Seung;Lee, Hyuk-Jin;Shin, Chan-Bai;Park, Chul-Hu
    • Journal of Institute of Control, Robotics and Systems
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    • v.17 no.1
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    • pp.31-37
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    • 2011
  • Recently gantry-type robot with 3 axes rectangular coordinates have been studied in the many industrial production equipment and machinery fields. To acquire a good handling and motion performance of this robot, reducing the settling-time and securing the accurate-transfer positioning under high-speed conditions should be required. However when robot is moved in high-speed, the large inertia of robot can lead to serious vibration of robot's head. The time-delayed control characteristics of this robot can also lead to tracking error. In this research, the analysis of the effects of higher order positional-profile is carried out to assure high-speed performance and stiffness specifications. To remove the residual vibration caused by kinematic coupling effect of dual-servo gantry, we develop a dual-servo gantry of rotary type that moving frame of x-axis rotates about z-axis. In order to decrease the tracking error, the 3 type lead-filter through system identification was applied respectively. From the experimental results, it was shown that zero-order series leader-filter has the best performance about tracking error and settling time.

A Case Study for a Process/Layout Design of a Sikhye Production Line (식혜(食醯) 생산(生産)라인의 공정(工程)/배치(配置) 설계(設計)에 대한 사례 연구)

  • Yang, Moon-Hee
    • IE interfaces
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    • v.16 no.4
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    • pp.450-462
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    • 2003
  • In this paper, we deal with a process and layout design for producing a planned amount of Sikhye in a given limited time period under a reasonable production schedule. We represent a Sikhye production line as a vector N, the element of which denotes the number of tanks required in each process and our objective is to find an appropriate vector which minimizes the total investment cost. We suggest a systematic method for finding an appropriate N and an appropriate layout to N. In detail, first, we decide the required sequence of processes and the required operations for each process and we estimate standard operating times. Second, constructing a precedence diagram, we find a critical path in order to reduce the total production lead time for a batch of Sikhye. Third, given a limited N space, we manage to construct manually each production schedule using both the processing times of the critical operations and transfer times. Finally, we find an optimal vector N which gives a minimum investment cost and meets both the time constraint and quantity constraint. In addition, with the estimated relative size of each tank, we suggest an appropriate conceptual layout design including an expansion area for future demands, based on the span technique used in the field of architectural design.

A Study of Production System and Simulation Model for Womens Wear Manufacture (여성복 생산현황과 생산라인 설계를 위한 시뮬레이션 모델 개발)

  • 조진숙;박상희
    • Journal of the Korean Society of Clothing and Textiles
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    • v.25 no.1
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    • pp.103-114
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    • 2001
  • In Korean clothing industry, most of the womens wear is manufactured by subcontractors. Because womens fashion is getting more rapidly changing, subcontractors production run of each orders is getting shorter too. Also the volume of each order is quite small compare to mens or childrens. So subcontractors are always in a hurry to adjust their production capacity to new order. Therefore they cannot afford to plan production line and allocate works efficiently enough to manufacture competitive products in terms of cost, lead time, as well as quality. The purpose of this study is to suggest a production planning model for womens apparel manufacture, which are relevant to the situation of Korean clothing industry.

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A Synchronous System Design of an Intelligent-Integrated Production & Logistics Systems (지능형 통합 생산 물류 시스템의 동기화된 시스템 설계)

  • Bae, Jae-Ho;Wang, Gi-Nam
    • IE interfaces
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    • v.12 no.2
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    • pp.222-236
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    • 1999
  • This paper presents a design and implementation of an intelligent-integrated production-logistics systems. The situation considered here is that there are multiple manufacturing plants and multiple distribution centers. Effective distribution resource and production planning are required to reduce inventory cost and to avoid inventory shortage. We propose an intelligent forecasting scheme of each distribution centers, adaptive inventory replenishment planning, distribution resource planning, and integrated production planning system. In forecasting a huge number of on-line model identification is performed using neural network approximation capability. An efficient adaptive replenishment planning and distribution resource planning are also presented in connection with forecasting scheme. An appropriate production is also requested based on production lead-time and the results of distribution planning. Experimental simulations are presented to verify the proposed approach using real data.

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Optimal Material Flow of AGV based Production Lines (자동안내운반기로 된 생산라인의 최적 물류흐름)

  • 장석화
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.12 no.19
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    • pp.73-78
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    • 1989
  • This paper concerns the production model that the Automatic Guided Vehicles(AGVs) is used as transporters in assembly line. The model suggests that assembly parts may inter the beginning of the line in multiple units instead entering one unit at a time. Costs are occured in proportion to the number of vehicle on the line and job flow time. Here, the objective of this model is to determine the number of vehicle to minimize the total cost for M products production. Theoretical results are proved which lead to the development of algorithm for solution search. The solution search procedure is illustrated by a numerical example.

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A Study of Optimization in the Queue, Finite Population (유한모집단 대열기법에 의한 최적화 연구)

  • 오충환
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.1 no.1
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    • pp.37-44
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    • 1978
  • The purpose of this study is to search for an efficient application method in solving delay-phenomenon problems which influence upon total production cost through case study. The method of this study is an experimental study based on cutting time data in lead cutting operations from "Lead Cutting Machine (Stripper)" and its service rate data from a large electronic products company which utilizes conveyor line system for the products "Car Stereo" The procedure of this experimental study is as follows; 1) Using loading(Man-Hour) analysis technique j,1 order to analyse and evaluate Production capacity, efficiency, operation and idle rate assembly charge, waiting and service cost -when its are controlled by stripper operator(server) 2) Establishing adequate waiting time model of finite population caused by the interference of 4 stripper machine which is drawn from mathematical statistics testing, that is, goodness of fit test in the waiting and service rate and to search for optimal solution by utilizing the above mentioned model The experimental result was that amount to 8,546,618won Per year was brought down, that is, by optimum point, it shows a decrease as compared with Present point. The major limitation of this experimental study is that the Queue in the Finite Population, so to speak. it comes from the interference of 4 stripper machine dealt with this case were limited only on the Car Stereo conveyor line. Further study of application of this application method to the areas such as material handling, personnel management marketing and transportation management is strong1y recommended.trong1y recommended.

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Web-based Draft Verification System for Injection Mold Design (사출금형설계를 위한 웹기반 구배 검증 시스템)

  • Yeon Kwang-Heum;Song In-Ho;Chung Sung-Chong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.29 no.10 s.241
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    • pp.1353-1360
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    • 2005
  • Injection-molded products serve a wide range of applications in our modem lives and their significance is ever increasing. However, difficulty of communication among related companies under the present system results in increase of lead time and decrease of production efficiency. The objective of this paper is the development of a web-based draft verification system in mold design processes. Although several commercial CAD systems offer draft verification functions, those systems are very expensive and inadequate to perform collaborative works. For collaborative work under the distributed environment, the proposed system uses native file transforming of CAD data into optimal format by using the ACIS kernel and InterOp. Functions of draft verification modules are constructed over the ActiveX control using the visual C++ and OpenGL. Therefore, collaborators related to the development of a new product are able to verify the draft and undercut over the Internet without commercial CAD systems. The system helps to reduce production cost, errors and lead-time to the market. Performance of the system is confirmed through various case studies.