The Experts below are selected from a list of 324 Experts worldwide ranked by 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 ...

  • LOT-SIZING RULE AND FREEZING THE Master Production Schedule UNDER CAPACITY CONSTRAINT AND DETERMINISTIC DEMAND
    Production and Operations Management, 2009
    Co-Authors: Xiande Zhao, Jinxing Xie, Qiyuan Jiang
    Abstract:

    This paper investigates the performance impact of lot-sizing rule (LSR) selection and freezing of the Master Production Schedule (MPS) in multi-item single-level systems with a single resource constraint under deterministic demand. The results of the study show that the selection of LSRS and the parameters for freezing the MPS have a significant impact on total cost, Schedule instability, and the service level of the system. However, the selection of LSRS does not significantly influence the selection of the MPS freezing parameters. The basic conclusions concerning the performance of the freezing parameters under a capacity constraint agreed with previous research findings without consideration of capacity constraints.

  • Freezing the Master Production Schedule under single resource constraint and demand uncertainty
    International Journal of Production Economics, 2003
    Co-Authors: Jinxing Xie, Xiande Zhao, T. S. Lee
    Abstract:

    Abstract This paper investigates the impact of freezing the Master Production Schedule (MPS) in multi-item single-level systems with a single resource constraint under demand uncertainty. It also examines the impact of environmental factors on the selection of MPS freezing parameters. A computer model is built to simulate Master Production scheduling activities in a multi-item system under a rolling time horizon. The result of the study shows that the parameters for freezing the MPS have a significant impact on total cost, Schedule instability and the service level of the system. Furthermore, the selection of freezing parameters is also significantly influenced by some environmental factors such as capacity tightness and cost structure. While some findings concerning the performance of MPS freezing parameters without capacity constraints can be generalised to the case of limited capacity, other conclusions under capacity constraints are different from those without capacity constraints.

  • 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.

Ray R. Venkataraman - One of the best experts on this subject based on the ideXlab platform.

  • Rolling horizon Master Production Schedule performance: A policy analysis
    Production Planning & Control, 2010
    Co-Authors: Ray R. Venkataraman, Michael P. D'itri
    Abstract:

    In this paper, a simulation experiment has been developed to examine the combined influence of the design, inventory and environmental factors on the cost performance of a rolling horizon Master Production Schedule. Specifically, a 2 5 factorial design was used to examine the effects associated with three rolling Schedule design policies, one inventory policy and one environmental condition of forecast error on MPS cost performance. The study was based on actual data from a paint company. Results suggest that the choice of appropriate lot-size and inventory policies have a significant influence on MPS costs and that there are indeed important interactions between these policies and other design factors of a rolling Schedule.

  • Effect of forecast errors on rolling horizon Master Production Schedule cost performance for various replanning intervals
    Production Planning & Control, 2010
    Co-Authors: Ray R. Venkataraman, Jay Nathan
    Abstract:

    Master Production Schedules are usually updated by the use of a rolling Schedule. Previous studies on rolling Schedules seem to form the consensus that frequent replanning of a Master Production Schedule (MPS) can increase costs and Schedule instability. Building on previous research on rolling Schedules, this study addresses the impact of overestimation or underestimation of demand on the rolling horizon MPS cost performance for various replanning frequencies. The MPS model developed in this paper is based on actual data collected from a paint company. Results indicate that under both the forecast errors conditions investigated in this study, a two-replanning interval provided the best MPS cost performance for this company environment. However, results from the sensitivity analysis performed on the MPS model indicate that when the setup and inventory carrying costs are high, a 1-month replanning frequency (frequent replanning) seems more appropriate for both of the above forecast error scenarios.

  • FREQUENCY OF REPLANNING IN A ROLLING HORIZON Master Production Schedule FOR A PROCESS INDUSTRY ENVIRONMENT: A CASE STUDY
    Production and Operations Management, 2009
    Co-Authors: Ray R. Venkataraman
    Abstract:

    This study addresses the problem of replanning frequency for a rolling horizon Master Production Schedule (MPS) in a process industry environment under demand certainty. The major contribution of this paper is the demonstration of how the appropriate replanning frequency for a MPS can be determined under the conditions of minimum batch-size Production restrictions in a rolling planning horizon setting. In addition, the problem environment for this study is an actual MPS operation that includes features such as multiple Production lines, multiple products, capacity constraints, minimum inventory requirements, and multiple goals. Actual data from a paint company are used to determine the appropriate replanning frequency for a rolling horizon MPS. Results indicate that a 2-month replanning frequency was the best at this firm because of the significant cost savings it provided when compared to actual company performance and the other replanning intervals.

  • Determination of Master Production Schedule replanning frequency for various forecast window intervals
    International Journal of Operations & Production Management, 1998
    Co-Authors: Jay Nathan, Ray R. Venkataraman
    Abstract:

    This paper examines the impact of forecast window intervals on replanning frequencies for a rolling horizon Master Production Schedule (MPS). The problem environment for this study is an actual MPS operation of a paint company and includes features such as multiple Production lines, multiple products, capacity constraints, minimum inventory requirements. A mixed integer goal programming model formulated for the MPS problem is used to analyze the impact of forecast window interval length on replanning frequencies and MPS performance in a rolling horizon setting. Given demand certainty, results indicate that the length of the forecast window interval influences the choice of replanning frequency for this company environment. A three‐month forecast window interval with a two‐month replanning frequency provided the best MPS performance in terms of total cost.

  • Disaggregation to a rolling horizon Master Production Schedule with minimum batch-size Production restrictions
    International Journal of Production Research, 1996
    Co-Authors: Ray R. Venkataraman, S. B. Smith
    Abstract:

    Building on previous research in the area of hierarchical Production planning and rolling Schedules, this paper is concerned with the disaggregation of aggregate plans to a rolling horizon Master Production Schedule when Production lot-sizes require minimum batch-size Production. Actual data from a process industry firm is used to test and validate the proposed rolling horizon Master Production scheduling model. The paper also examines the impact of forecast windows on the performance of a rolling Schedule when Production quantities of individual product items are based on minimum batch-size Production. Results indicate that the model's performance is superior to actual company performance in terms of total cost and increasing the length of the forecast window can increase costs.

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

  • Freezing the Master Production Schedule under single resource constraint and demand uncertainty
    International Journal of Production Economics, 2003
    Co-Authors: Jinxing Xie, Xiande Zhao, T. S. Lee
    Abstract:

    Abstract This paper investigates the impact of freezing the Master Production Schedule (MPS) in multi-item single-level systems with a single resource constraint under demand uncertainty. It also examines the impact of environmental factors on the selection of MPS freezing parameters. A computer model is built to simulate Master Production scheduling activities in a multi-item system under a rolling time horizon. The result of the study shows that the parameters for freezing the MPS have a significant impact on total cost, Schedule instability and the service level of the system. Furthermore, the selection of freezing parameters is also significantly influenced by some environmental factors such as capacity tightness and cost structure. While some findings concerning the performance of MPS freezing parameters without capacity constraints can be generalised to the case of limited capacity, other conclusions under capacity constraints are different from those without capacity constraints.

  • 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.

André Thomas - One of the best experts on this subject based on the ideXlab platform.

  • Simulation of Less Master Production Schedule Nervousness Model
    IFAC Proceedings Volumes, 2016
    Co-Authors: Carlos Herrera, André Thomas
    Abstract:

    In Production decision making systems, Master Production Schedule (MPS) states the requirements for individual end items by date and quantity. The solution sensitivity to demand forecast changes, unforeseen supplier and Production problem occurrences, is known as nervousness. This feature cause undesirable effects at tactical and operational levels. Some of these effects are Production and inventory cost increases and, also, negative impacts on overall and labor productivity. To tackle this problem, we proposed a Mixed Integer Programming (MIP) model where nervousness reduction is carry out finding minimal suboptimal solutions. We perform a simulation under rolling planning horizon environment considering stochastic demand. Results of simulation show that, at each time demand changes take place the model can adjust the solution to achieve less nervousness without a significative change in cost performance.

  • A reactive decision-making approach to reduce instability in a Master Production Schedule
    International Journal of Production Research, 2015
    Co-Authors: Carlos Herrera, André Thomas, Sana Belmokhtar-berraf, Victor Parada
    Abstract:

    One of the primary factors that impact the Master Production scheduling performance is demand fluctuation, which leads to frequently updated decisions, thereby causing instability. Consequently, global cost deteriorates, and productivity decreases. A reactive approach based on parametric mixed-integer programming (MIP) is proposed that aims to provide a set of plans such that a compromise between Production cost and Production stability is ensured. Several stability measures and their corresponding MIP model are proposed. An experimental study is performed to highlight the effectiveness of the reactive approach with regard to the proposed performance measures. It is observed that an improvement in stability does not mean a significant increase in the total Production cost. Furthermore, the procedure yields a set of plans that in practice would enable flexible management of Production.

  • Formulation for less Master Production Schedule instability under rolling horizon
    2009
    Co-Authors: Carlos Herrera, André Thomas
    Abstract:

    In Manufacturing Planning and Control Systems, the Master Production Schedule (MPS) makes a link between tactical and operational levels, taking into account information provided by end items, demand forecast as well as Sales and Operations Planning (S&OP) suggestions. Therefore, MPS plays an important role to maintain an adequate customers service level and an efficient Production system. In a rolling planning horizon, MPS is periodically computed over whole operational horizon. The differences between Scheduled quantities obtained by this process are related to MPS instability. This feature of MPS has negative effects, both, at tactical level and also at operational one. In this paper, a Mixed Integer Programming model is proposed for MPS instability. The proposed model considers instability minimization in addition to inventory costs and set up. Simulation is used to take into account stochastic demand. Computation experiments are presented in order to show the efficiency of this approach by finding stable MPS without a considerably increase in the total cost.

  • Simulation Reduction Models Approach Using Neural Network
    2008
    Co-Authors: Philippe Thomas, Denise Choffel, André Thomas
    Abstract:

    Simulation is often used for the evaluation of a Master Production Schedule (MPS). Also, the goal of this paper is the study of the design of a simulation model by reducing its complexity. According to theory of constraints, we want to build reduced models composed exclusively by bottleneck and, in order to do that, a neural network, particularly a multilayer perceptron, is used. Moreover, the structure of the network is determined by using a pruning procedure. This approach is applied to a sawmill flow shop case

  • The two level Master Production Schedule and planning bills in a just in time MRP context
    International Journal of Production Economics, 2000
    Co-Authors: Samir Lamouri, André Thomas
    Abstract:

    Abstract The evolution of industrial firms has recently passed from a strong growth phase to a phase where there is a greater complexification of products: widening the range of products in catalogues, diversification and personalization of models. The current trend is to use, with Production management techniques such as classical manufacturing resource planning (MRP2), the concept of two level Master Production Schedule (MPS), using planning bills with percentages indicating the probability that such or such an option will be used. This necessitates, however, the implementation of a rigorous approach to continuous improvement using just in time (JiT) and total quality (TQ) concepts. In the first part of our paper we discuss principles of operating two level MPS; secondly, we analyze these effects on management and organization. Our paper is based on a case study.

Mustapha Sali - One of the best experts on this subject based on the ideXlab platform.

  • Mass customisation impact on bill of materials structure and Master Production Schedule development
    International Journal of Production Research, 2016
    Co-Authors: Clément Chatras, Vincent Giard, Mustapha Sali
    Abstract:

    The customisation of a vehicle on a Production line results from the assembly of several hundreds of alternative components. Bills of Material (BOM) are usually made for operational purposes (to define the list of components to be assembled on a vehicle), for planning (to anticipate component procurement needs) and for commercial needs (guide customer choice and prepare sales forecasts). In the automotive industry, the diversity of end products which results from this combinatorial process (several millions) is such as no solution proposed in the literature allows to easily list the BOMs for all these vehicles. In our paper, we describe and theorise a solution used for many years by several carmakers, which consists in introducing a commercial description of the products in addition to their common organic representation. We show that this solution is an extension of the generic and modular BOM theory, recognised to be the most advanced solutions proposed in the literature. While fully meeting commercial and Production control needs, this product description paradigm has limitations when it comes to determining the Master Production Schedules (MPS) at end product level beyond the frozen horizon, as performed by several automakers. An alternative approach defining MPSs at alternative component level is proposed in the literature. However, this approach also has several drawbacks that we point out. To overcome these issues, we propose a number of possible strategic and organisational tracks of improvement.

  • high variety impacts on Master Production Schedule a case study from the automotive industry
    IFAC-PapersOnLine, 2015
    Co-Authors: Clément Chatras, Vincent Giard, Mustapha Sali
    Abstract:

    In mass customization Production systems, end-products diversity proceeds from the combination of hundreds of alternative components (ACs) involved in the final assembly stage. Since diversity is very important, forecasts cannot be done directly at the end-product level for Production planning purposes. Thus, it is generally agreed in a mass customization context that Master Production Schedules (MPSs) have to be defined for each AC rather than each end-product. Nevertheless, some issues may hamper this approach. First, the MPSs have to be consistent with the technical and commercial constraints that prevent some ACs combinations. Second, due to longer lead times resulting from globalization, Production planning must accommodate with uncertainty over the frozen horizon. To address these issues in the automotive sector, a new way to represent product through the concept of the Alternative Services (ASs), which refers to the alternative commercial features offered to the customer, has been introduced by some carmakers. This paper proposes a description of this approach and discusses its relevance regarding the issues of the classical Production planning process. Some suggestions are proposed to overcome the limitations of the approach based on the ASs.

  • Monitoring of the upstream part of a supply chain dedicated to customized mass Production with a revisited version of MRP
    2012
    Co-Authors: Vincent Giard, Mustapha Sali
    Abstract:

    This article focuses on the monitoring of a supply chain dedicated to the mass Production of strongly diversi-fied products. Specifically, we are interested in the part of this chain that contributes to the Production of a set of alter-native modules assembled on a work station of one or several assembly lines, whose Production levels are stable. The MRP approach is adopted for the monitoring of this chain. The distance between the Production units leads to a mix between Production to stock and Production to order. In this article, we establish the relations that allow us to define, in a steady state, the quantities to produce that address the requirements of the Master Production Schedule and that are partially or completely random to limit the stockout risk to a very low predetermined level. We will distinguish two cases by accounting for, or not accounting for, problems that are related to quality.

  • Monitoring of the upstream part of a supply chain dedicated to the customized mass Production with a revisited version of MRP
    2012
    Co-Authors: Vincent Giard, Mustapha Sali
    Abstract:

    This article focuses on the monitoring of a supply chain dedicated to the mass Production of strongly diversi-fied products. Specifically, we are interested in the part of this chain that contributes to the Production of a set of alter-native modules assembled on a work station of one or several assembly lines, whose Production levels are stable. The MRP approach is adopted for the monitoring of this chain. The distance between the Production units leads to a mix between Production to stock and Production to order. In this article, we establish the relations that allow us to define, in a steady state, the quantities to produce that address the requirements of the Master Production Schedule and that are partially or completely random to limit the stockout risk to a very low predeterm