The Experts below are selected from a list of 237 Experts worldwide ranked by ideXlab platform
F.t.s Chan - One of the best experts on this subject based on the ideXlab platform.
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Effect of kanban size on just-in-time manufacturing systems
Journal of Materials Processing Technology, 2001Co-Authors: F.t.s ChanAbstract:Abstract Setting kanban sizes is one of the first decisions that users of kanban system must address, yet researchers have largely assumed kanban sizes to be given. This paper investigates the effect of varying kanban size on the performance of just-in-time (JIT) manufacturing systems. Two types of JIT production systems, the Pull-type and the Hybrid-type are analysed using computer simulation models. The performance measures considered simultaneously are the fill rate, in-Process Inventory, and manufacturing lead time. Parameters such as demand rate, Processing time, and kanban size are taken into consideration, thereby finding the possible solutions of the kanban size that can be employed to achieve the most favourable conditions for production. A favourable condition usually refers to the ability of the system to produce finished goods at a shortest possible lead time, which the customers are always demanding for. Both the single product and multi-products manufacturing environments are investigated. With reference to the analysis, for a single product, as the kanban size increased, the fill rate decreased, whilst with both the in-Process Inventory and the manufacturing lead time increased. Generally, for multi-products manufacture, it was observed that as the kanban size increased, the fill rate increased with a decrease in the manufacturing lead time. However, for multi-products the interaction between the manufacturing lead time and the fill rate is discussed in depth in this paper.
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Effect of kanban size on just-in-time manufacturing systems
Journal of Materials Processing Technology, 2001Co-Authors: F.t.s ChanAbstract:Setting kanban sizes is one of the first decisions that users of kanban system must address, yet researchers have largely assumed kanban sizes to be given. This paper investigates the effect of varying kanban size on the performance of just-in-time (JIT) manufacturing systems. Two types of JIT production systems, the Pull-type and the Hybrid-type are analysed using computer simulation models. The performance measures considered simultaneously are the fill rate, in-Process Inventory, and manufacturing lead time. Parameters such as demand rate, Processing time, and kanban size are taken into consideration, thereby finding the possible solutions of the kanban size that can be employed to achieve the most favourable conditions for production. A favourable condition usually refers to the ability of the system to produce finished goods at a shortest possible lead time, which the customers are always demanding for. Both the single product and multi-products manufacturing environments are investigated. With reference to the analysis, for a single product, as the kanban size increased, the fill rate decreased, whilst with both the in-Process Inventory and the manufacturing lead time increased. Generally, for multi-products manufacture, it was observed that as the kanban size increased, the fill rate increased with a decrease in the manufacturing lead time. However, for multi-products the interaction between the manufacturing lead time and the fill rate is discussed in depth in this paper. © 2001 Elsevier Science B.V. All rights reserved.link_to_subscribed_fulltex
Stanley B. Gershwin - One of the best experts on this subject based on the ideXlab platform.
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Scheduling manufacturing systems with work-in-Process Inventory control: Reentrant systems
Operations-Research-Spektrum, 1996Co-Authors: S. X. Bai, Stanley B. GershwinAbstract:In this paper, we propose a procedure for production flow control in reentrant manufacturing systems. The system under study consists of N machines and produces M product types simultaneously. Each part goes through the system following a predefined Process and may visit a machine many times. All machines are subject to random failures and need random repair times. The scheduling objectives are to keep the production close to demand and to keep the WIP Inventory level and cycle times at low values. The model is motivated by semiconductor fabrication production. A three-level hierarchical controller is constructed to regulate the production. At the top level of this hierarchy, we perform capacity planning by selecting the desirable buffer sizes and the target production level for each operation. A production flow rate controller is at the middle level which recalculates the production rates whenever a machine fails or is starved or blocked. The loading times for individual parts are determined at the bottom level of the hierarchy. Comparison with alternative control is made through simulation and it shows that the control policy performs well. In diesem Beitrag wird ein hierarchischer Planungsansatz zur Steuerung eines Produktionssystems mit N Maschinen betrachtet. Für jede von vielen herzustellenden Produktarten ist die Maschinenfolge durch den jeweiligen Produktionsprozeß fest vorgegeben. Gegebenenfalls sind Maschinen mehrmals zu durchlaufen. Außerdem sind zufällige Maschinenausfälle und Reparaturzeiten zu beachten. Solche Systeme treten z.B. bei der Halbleiterfertigung auf. Ziel der Planung ist eine möglichst bedarfssynchrone Produktion bei niedrigen Lagerbeständen an Halbfertigfabrikaten und hohen Produktionsraten. In der obersten Ebene einer dreistufigen Planungshierarchie werden im Rahmen einer Kapazitätsplanung wünschenswerte Puffergrößen und Produktionsraten der Maschinen ermittelt. In der mittleren Ebene erfolgt eine Anpassung der Produktionsraten, um Störungen des Systems durch Maschinenausfälle oder Blockierung von Maschinen zu beseitigen. In der untersten Planungsebene wird eine Durchlaufterminierung vorgenommen. Eine Simulationsuntersuchung zeigt, daß der vorgeschlagene Planungsansatz gute Ergebnisse liefert.
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Scheduling manufacturing systems with work-in-Process Inventory control: single-part-type systems
Iie Transactions, 1995Co-Authors: S. X. Bai, Stanley B. GershwinAbstract:A real-time algorithm is developed for scheduling single-part-type production lines with work-in-Process Inventory buffers. We consider three classes of activities: operations, failures and repairs, and starvation and blockage. The scheduling objectives are to keep the actual production close to the demand, the work-in-Process (WIP) Inventory level low, and the cycle time short. A three-level hierardhical controller is constructed to regulate the production. At the top level, we determine the desirable buffer sizes and the target production level for each operation. At the middle level is a production flow rate controller that recalculates the production rates whenever a machine fails or is starved or blocked. The loading times for individual parts are determined at the bottom level of the hierarchy. The production scheduling algorithm is evaluated by using computer simulations for a variety of cases. Compared with a transfer line policy, a significant improvement in system performance is observed.
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Scheduling manufacturing systems with work-in-Process Inventory control: multiple-part-type systems
International Journal of Production Research, 1994Co-Authors: S. X. Bai, Stanley B. GershwinAbstract:Abstract We have studied here the real-time production scheduling problem for multiple-part-type flow shops. The system under consideration consists of many machines and produces many product types. Each part goes through the system following a pre-defined routeing and may visit each machine at most once. We consider three classes of activities: operations, failures or repairs and starvation or blockage. The scheduling objectives are to keep the actual production close to the demand and to reduce the work-in-Process Inventory and cycle time. A three-level hierarchical production control model is developed to regulate production for the manufacturing systems. The control policy specifies how to react to machine failures. It also tells how to allocate limited system capacity among all the part types. It utilizes the material and the space in the storage buffers to alleviate the propagation of a failure to other machines in the system.
Fang Ailian - One of the best experts on this subject based on the ideXlab platform.
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A Simulation Model of a Stochastic Batch Process Inventory System
Computer Engineering, 2003Co-Authors: Fang AilianAbstract:In this paper,the computer simulation technique is utilized to study the batch ProcessInventory system including stochastic factors. A simulation method is proposed, and a simulation model is presented. An optimal batch Process Inventory policy can be selected with the method of the system simulation.
Franziska Rabenschlag - One of the best experts on this subject based on the ideXlab platform.
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Measuring recovery: validity of the "Recovery Process Inventory" and the "Recovery Attitudes Questionnaire".
Psychiatry research, 2013Co-Authors: Matthias Jaeger, Albrecht Konrad, Sebastian Rueegg, Franziska RabenschlagAbstract:Considerable lack of publications and inconsistent results on construct validity make it difficult to choose an appropriate instrument to measure recovery. The aim of the present study was to evaluate additional psychometric aspects of two established measures of personal recovery with differing focuses. Bivariate associations of the recovery measures with personal, clinical and subjective factors were conducted as indicators of concurrent (convergent and divergent) validity. The scales were also tested concerning internal consistency. The sample comprised of 81 inpatients on an acute psychiatric ward (main diagnoses: 27% substance-related disorders, 27% schizophrenic disorders, 25% affective disorders, 10% neurotic or stress-related disorders, and 11% personality disorders). The "Recovery Attitudes Questionnaire (RAQ)" has to be reevaluated before further administration due to serious psychometric shortcomings concerning internal consistency and concurrent validity. The "Recovery Process Inventory (RPI)" total scale showed acceptable concurrent and within-scale validity and can be recommended in order to measure the personal recovery Process for clinical and scientific purposes.
S. X. Bai - One of the best experts on this subject based on the ideXlab platform.
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Scheduling manufacturing systems with work-in-Process Inventory control: Reentrant systems
Operations-Research-Spektrum, 1996Co-Authors: S. X. Bai, Stanley B. GershwinAbstract:In this paper, we propose a procedure for production flow control in reentrant manufacturing systems. The system under study consists of N machines and produces M product types simultaneously. Each part goes through the system following a predefined Process and may visit a machine many times. All machines are subject to random failures and need random repair times. The scheduling objectives are to keep the production close to demand and to keep the WIP Inventory level and cycle times at low values. The model is motivated by semiconductor fabrication production. A three-level hierarchical controller is constructed to regulate the production. At the top level of this hierarchy, we perform capacity planning by selecting the desirable buffer sizes and the target production level for each operation. A production flow rate controller is at the middle level which recalculates the production rates whenever a machine fails or is starved or blocked. The loading times for individual parts are determined at the bottom level of the hierarchy. Comparison with alternative control is made through simulation and it shows that the control policy performs well. In diesem Beitrag wird ein hierarchischer Planungsansatz zur Steuerung eines Produktionssystems mit N Maschinen betrachtet. Für jede von vielen herzustellenden Produktarten ist die Maschinenfolge durch den jeweiligen Produktionsprozeß fest vorgegeben. Gegebenenfalls sind Maschinen mehrmals zu durchlaufen. Außerdem sind zufällige Maschinenausfälle und Reparaturzeiten zu beachten. Solche Systeme treten z.B. bei der Halbleiterfertigung auf. Ziel der Planung ist eine möglichst bedarfssynchrone Produktion bei niedrigen Lagerbeständen an Halbfertigfabrikaten und hohen Produktionsraten. In der obersten Ebene einer dreistufigen Planungshierarchie werden im Rahmen einer Kapazitätsplanung wünschenswerte Puffergrößen und Produktionsraten der Maschinen ermittelt. In der mittleren Ebene erfolgt eine Anpassung der Produktionsraten, um Störungen des Systems durch Maschinenausfälle oder Blockierung von Maschinen zu beseitigen. In der untersten Planungsebene wird eine Durchlaufterminierung vorgenommen. Eine Simulationsuntersuchung zeigt, daß der vorgeschlagene Planungsansatz gute Ergebnisse liefert.
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Scheduling manufacturing systems with work-in-Process Inventory control: single-part-type systems
Iie Transactions, 1995Co-Authors: S. X. Bai, Stanley B. GershwinAbstract:A real-time algorithm is developed for scheduling single-part-type production lines with work-in-Process Inventory buffers. We consider three classes of activities: operations, failures and repairs, and starvation and blockage. The scheduling objectives are to keep the actual production close to the demand, the work-in-Process (WIP) Inventory level low, and the cycle time short. A three-level hierardhical controller is constructed to regulate the production. At the top level, we determine the desirable buffer sizes and the target production level for each operation. At the middle level is a production flow rate controller that recalculates the production rates whenever a machine fails or is starved or blocked. The loading times for individual parts are determined at the bottom level of the hierarchy. The production scheduling algorithm is evaluated by using computer simulations for a variety of cases. Compared with a transfer line policy, a significant improvement in system performance is observed.
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Scheduling manufacturing systems with work-in-Process Inventory control: multiple-part-type systems
International Journal of Production Research, 1994Co-Authors: S. X. Bai, Stanley B. GershwinAbstract:Abstract We have studied here the real-time production scheduling problem for multiple-part-type flow shops. The system under consideration consists of many machines and produces many product types. Each part goes through the system following a pre-defined routeing and may visit each machine at most once. We consider three classes of activities: operations, failures or repairs and starvation or blockage. The scheduling objectives are to keep the actual production close to the demand and to reduce the work-in-Process Inventory and cycle time. A three-level hierarchical production control model is developed to regulate production for the manufacturing systems. The control policy specifies how to react to machine failures. It also tells how to allocate limited system capacity among all the part types. It utilizes the material and the space in the storage buffers to alleviate the propagation of a failure to other machines in the system.
