The Experts below are selected from a list of 186072 Experts worldwide ranked by ideXlab platform

Marija Bogataj - One of the best experts on this subject based on the ideXlab platform.

David Bogataj - One of the best experts on this subject based on the ideXlab platform.

Xiande Zhao - One of the best experts on this subject based on the ideXlab platform.

  • Multilevel lot-sizing heuristics and freezing the master production schedule in Material Requirements planning systems
    Production Planning & Control, 2010
    Co-Authors: Xiande Zhao, Jinxing Xie
    Abstract:

    This paper compares the performance of a new improved heuristic (STIL) proposed by Coleman and McKnew (1991, Decision Sciences , 22 , 136-156) Wagner-Whitin (WW), cost-modified (MWW) and some simple lot-sizing rules found to perform well by Zhao et al . (1995, International Journal of Production Research , 33 (8), 2241-2276). It also investigates the impact of the lot-sizing ruleson the selection ofthe parametersfor freezing the master production schedule (MPS). The experimental settings include forecasting, master production scheduling and Material Requirements planning under a rolling time horizon. The result of the study shows that the STIL heuristic, WW rule and MWW rule do not really outperform the simple costmodified Silver-Meal (MSM) and the Silver-Meal/Lot-forLot (SM/LFL), even though they require substantially higher comheuristics against those of the Wagner-Whitin putation time. The study also shows that the selection of the parameters for freezing the MPS is not significantly influenced by the ...

  • Multilevel Lot-Sizing Heuristics and Freezing the Master Production Schedule in Material Requirements Planning Systems (Subject Areas: Material Requirements Planning, Master Production Scheduling, Lot-Sizing, Simulation)
    1998
    Co-Authors: Xiande Zhao, Jinxing Xie
    Abstract:

    This paper compares the performance of a new improved heuristic (STIL) proposed by Coleman and McKnew (1991) against those of the Wagner-Whitin (WW), cost-modified WagnerWhitin (MWW) and some simple lot-sizing rules found to perform well by Zhao et al. (1995). It also investigates the impact of the lot-sizing rules on the selection of the parameters for freezing the master production schedule (MPS). The experimental settings include forecasting, master production scheduling and Material Requirements planning under a rolling time horizon. The result of the study shows that the STIL heuristic, the WW rule and the MWW rule do not really outperform the simple cost-modified Silver-Meal (MSM) and the Silver-Meal/Lot-for-Lot (SM/LFL) even though they require substantially higher computation time. The study also shows that the selection of the parameters for freezing the MPS is not significantly influenced by the selection of the lot-sizing rules. (Subject Areas: Material Requirements Planning, Master Production Scheduling, Lot-Sizing, Simulation)

  • Lot-sizing rules and freezing the master production schedule in Material Requirements planning systems
    International Journal of Production Economics, 1997
    Co-Authors: Xiande Zhao, Kokin Lam
    Abstract:

    Abstract Freezing the master production schedule (MPS) is one of the frequently used methods for reducing schedule instability in multilevel Material Requirements planning (MRP) systems. The selection of lot sizing rule and the selection of MPS freezing parameters have been shown to significantly influence MRP performance. This study examines the impact of lot-sizing rule selection on the selection of MPS freezing parameters under rolling time horizons under deterministic demand. A model is built to simulate the Master Production Scheduling and Material Requirements Planning operations in a make-to-order environment. The results show that the selection of lot-sizing rules significantly influences the selection of MPS freezing parameters.

  • Freezing the master production schedule in multilevel Material Requirements planning systems under deterministic demand
    Production Planning & Control, 1996
    Co-Authors: Xiande Zhao, T. S. Lee
    Abstract:

    Abstract This paper extends the studies by Sridharan, Berry, and Udayabhanu from single-level MPS systems to multilevel Material Requirements planning (MRP) systems, and examines the impact of product structure, lot-sizing rules and cost parameters upon the selection of MPS freezing parameters under deterministic demand. A model is built to simulate the master production scheduling and Material Requirements planning operations in a make-to-order environment. The results show that all the MPS freezing parameters studied have a significant impact upon total inventory costs and schedule instability in multilevel MRP systems. First, the order-based freezing method is preferable to the period-based method. Secondly, the study finds that increasing the freezing proportion reduces both total inventory costs and schedule instability. This finding contradicts the finding by Sridharan et al. in single-level systems. Thirdly, the study finds that a higher replanning periodicity results in both lower total inventory ...

  • Lot-sizing rules and freezing the master production schedule in Material Requirements planning systems under demand uncertainty
    International Journal of Production Research, 1995
    Co-Authors: Xiande Zhao, J. C. Goodale, T. S. Lee
    Abstract:

    Freezing the master production schedule (MPS) is one of the frequently used methods for reducing schedule instability in multilevel Material Requirements planning (MRP) systems. The selection of the lot-sizing rule is an important decision in MRP systems and has been shown to significantly influence MRP performance. This study examines the interaction between the selection of lot-sizing rules and the selection of MPS freezing parameters under rolling time horizons under different demand uncertainty conditions. The findings of this study enhance the understanding of multilevel MRP performance in a more realistic environment and help MRP practitioners select the proper lot-sizing rule and MPS freezing parameters.

T. S. Lee - One of the best experts on this subject based on the ideXlab platform.

  • Freezing the master production schedule in multilevel Material Requirements planning systems under deterministic demand
    Production Planning & Control, 1996
    Co-Authors: Xiande Zhao, T. S. Lee
    Abstract:

    Abstract This paper extends the studies by Sridharan, Berry, and Udayabhanu from single-level MPS systems to multilevel Material Requirements planning (MRP) systems, and examines the impact of product structure, lot-sizing rules and cost parameters upon the selection of MPS freezing parameters under deterministic demand. A model is built to simulate the master production scheduling and Material Requirements planning operations in a make-to-order environment. The results show that all the MPS freezing parameters studied have a significant impact upon total inventory costs and schedule instability in multilevel MRP systems. First, the order-based freezing method is preferable to the period-based method. Secondly, the study finds that increasing the freezing proportion reduces both total inventory costs and schedule instability. This finding contradicts the finding by Sridharan et al. in single-level systems. Thirdly, the study finds that a higher replanning periodicity results in both lower total inventory ...

  • Lot-sizing rules and freezing the master production schedule in Material Requirements planning systems under demand uncertainty
    International Journal of Production Research, 1995
    Co-Authors: Xiande Zhao, J. C. Goodale, T. S. Lee
    Abstract:

    Freezing the master production schedule (MPS) is one of the frequently used methods for reducing schedule instability in multilevel Material Requirements planning (MRP) systems. The selection of the lot-sizing rule is an important decision in MRP systems and has been shown to significantly influence MRP performance. This study examines the interaction between the selection of lot-sizing rules and the selection of MPS freezing parameters under rolling time horizons under different demand uncertainty conditions. The findings of this study enhance the understanding of multilevel MRP performance in a more realistic environment and help MRP practitioners select the proper lot-sizing rule and MPS freezing parameters.

  • freezing the master production schedule for Material Requirements planning systems under demand uncertainty
    Journal of Operations Management, 1993
    Co-Authors: Xiande Zhao, T. S. Lee
    Abstract:

    Abstract Freezing the master production schedule (MPS) is one of the commonly used methods to reduce schedule instability or nervousness in Material Requirements planning (MRP) systems. However, the impact of MPS freezing parameters in multilevel MRP systems has not been fully understood. This paper investigates the impact of MPS freezing parameters on the total cost, schedule instability and service levels in multilevel MRP systems under demand uncertainty conditions. The MPS freezing parameters included in this study are: (1) planning horizons; (2) freezing proportions; (3) freezing methods; and (4) replanning periodicity. The paper also examines the impact of forecasting errors on the selection of MPS freezing parameters and system performance. A model was built to simulate forecasting, master production scheduling and Material Requirements planning operations in a manufacturing company. The company is assumed to produce two end items with no component commonality. The company operates in a make-to-stock environment. No back orders are allowed and thus any shortage will become a loss of sales. Through a comprehensive simulation experiment and statistical analysis, the study arrived at the following findings: (1) Forecasting errors significantly increase total costs and schedule instability, and reduce the service level in multilevel MRP systems. The selection of forecasting models has a significant impact on system performance. In addition, forecasting errors also influence the selection of some MPS freezing parameters. (2) A planning horizon of four natural ordering cycles results in a lower total cost and schedule instability and a higher service level than a planning horizon of eight natural ordering cycles under demand uncertainty condition, but a higher total cost and schedule instability under deterministic demand conditions. Thus the prolongation of the planning horizon can actually worsen MRP performance under demand uncertainty conditions while it improves MRP performance under deterministic demand conditions. (3) A higher freezing proportion results in a lower total cost and schedule instability, and does not influence the service level under deterministic demand conditions. Therefore, freezing the entire planning horizon is the best option in this case. However, a higher freezing proportion often results in a higher cost, and a lower service level, while reducing schedule instability under demand uncertainty conditions. As a result, the choice of freezing proportion should be based on the required trade-offs among the three performance criteria under demand uncertainty conditions. (4) The order-based freezing method results in lower total costs than the period-based method in most cases. In terms of schedule instability, the period-based method with freezing proportion of 1.0 performs the best. In terms of service level, the period-based method with freezing proportion of 1.0 performs the worst; the period-based method with freezing proportion of 0.25 performs the best. The selection of the freezing method should be considered in combination with the freezing proportion to achieve the required trade-offs among the performance criteria of total costs, schedule instability, and service level. (5) A higher replanning periodicity results in a lower total cost, schedule instability, and a higher service level under both deterministic and stochastic demand conditions. Thus, less frequent replanning improves system performance. These conclusions may help MRP practitioners to select MPS freezing parameters in multilevel MRP systems.

Kokin Lam - One of the best experts on this subject based on the ideXlab platform.

  • Lot-sizing rules and freezing the master production schedule in Material Requirements planning systems
    International Journal of Production Economics, 1997
    Co-Authors: Xiande Zhao, Kokin Lam
    Abstract:

    Abstract Freezing the master production schedule (MPS) is one of the frequently used methods for reducing schedule instability in multilevel Material Requirements planning (MRP) systems. The selection of lot sizing rule and the selection of MPS freezing parameters have been shown to significantly influence MRP performance. This study examines the impact of lot-sizing rule selection on the selection of MPS freezing parameters under rolling time horizons under deterministic demand. A model is built to simulate the Master Production Scheduling and Material Requirements Planning operations in a make-to-order environment. The results show that the selection of lot-sizing rules significantly influences the selection of MPS freezing parameters.