No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Integrated Material Planning and Operations Scheduling (IMPOS)
International Journal of Production Research
Abstract
This paper presents an Integrated approach for Material Planning and finite Operations Scheduling (IMPOS). The approach assumes the existence of a system that provides a relative priority measure for customer orders, based on a predetermined set of factors including--but not limited to--due dates. Orders are sequenced on descending order of the priority measures to form the Master Production Sequence (MPS) list. Starting from the top of the MPS list, orders are planned one at a time, by determining their respective quantity requirements first. The next phase schedules the requirements by time allocation of the available finite resources to their operational requirements. The IMPOS approach attempts to reduce production lead times during its finite scheduling procedure through analysis of the details of each operation in conjunction with other associated operations and the ordering policy applied. Generating finite schedules quickly enables IMPOS to handle effectively the dynamic behaviour of the manufacturing environment. The approach is detailed and exemplified.
... An optimization model for calculating components requirement planning, where input is the production planning in the master plan, is formulated by Bahl and Ritzman (1984) and Toro and Delgado (2010). Moreover, other authors such as Hastings, Marshall and Willis (1982), Ho and Chang (2001), Fallah and Shayan (2002), Chen and Ping (2007), Masuchun andThepmanee (2009), andShah andLerapetritou (2012), present mixed-integer linear programming models to set up a system to integrate production planning of items in the MRP and operations scheduling, guaranteeing an appropriate materials supply in the plant. In these models, capacity constraints, operation sequences, setup timing, and delivery deadlines in a multi-item setting are considered. ...
Introduction.
This research addresses the problem of internal materials supply operations in a pre-milling type concentrate food plant. The required amount of raw materials for production in the internal supply chain is determined by minimizing the total relevant operational cost, made up by the setup cost and the stock maintenance cost, which maximizes efficiency of the resources used in the process. This study takes into account such factors as capacity of the hoppers, the time-dependent setup sequence, routes of supply hoppers, filling rates and supply times, based on a model of mixed-integer linear programming.
Objective:
Provide a strategy that allows efficient use of resources in the production process, subjected to the demand of materials from the material requirements planning (MRP) of the company under study.
Materials and methods.
The short-term multi-period model defines the scheduling of elevators and conveyors for each time period, and the amount of raw materials that is sent to each hopper and bins.
Results.
This research determines the amount of initial stock required to operate, as well as the operations strategy that the company under study must follow, so that it meets the demand for raw materials, making efficient use of the resources used in the production process.
Conclusion.
In the analysis of results and presentation of scenarios, the most representative cost, the one related to stock maintenance, could be observed. Since this is a critical factor for companies belonging to this sector, we present an innovative proposal, both in practice and in the literature, to contribute to minimizing the total setup cost and the cost of maintenance of raw material stock in hoppers through a rational use of resources.
... An integrated approach for material planning and finite operation scheduling (IMPOS) was presented by (Fallah, 2002). The approach assumes the existence of a system that provides a relative priority measure for customer orders, based on a predetermined set of factors including -but not limited to -due dates. ...
This paper discusses about the scheduling problem of a multi product manufacturing industry. Often there has been a problem of applying optimization algorithms to solve the makespan minimization criterion of a job shop due to its inherent NP-hard nature. It is therefore unrealistic to try obtaining a solution through a
commercial solver in polynomial time. In this context, we propose a computationally effective heuristic, which is based on the powers-of-two policy in inventory, for solving the minimum makespan problem of job shop scheduling. The research discussed in the current paper is a real time scheduling problem faced by a large scale and complex turbine manufacturing job shop. It is worth noting that by integrating the material
requirements planning (MRP) with the feasible schedule obtained, this policy also proves to be useful in minimizing the inventory costs.
... Furthermore , there is limited amount of available working time due to technical limitations in a planning period. And, dealing with such technical limitations results in a complicated problem that was mainly treated by heuristics and rule of thumbs (Fallah & Shayan, 2002). Also, these decisions (i.e. ...
This paper proposes an integer linear programming formulation for a simultaneous lot sizing and scheduling problem in a job shop environment. Among others, one of our realistic assumptions is dealing with flexible machines which enable the production manager to change their working speeds. Then, a number of valid inequalities are developed based on problem structures. As the valid inequalities can help in reducing the non-optimal parts of the solution space, they are dealt with as some cutting planes. The proposed cutting planes are used to solve the problem in (i) cut-and-branch, and (ii) branch-and-cut approaches. The performance of each cutting plane is investigated with CPLEX 12.2 on a set of randomly-generated test data. Then, some performance criteria are identified and the proposed cutting planes are ranked by TOPSIS method. (c) 2013 Elsevier B.V. All rights reserved.
... In more details, a similar procedure such as that shown in Fig. 1were generally used in traditional (i.e. MRP-based) production management with some minor variations (Fallah and Shayan [4], Koh et al. [12], Waters [20], Pochet and Wolsey [17]). The decisions are usually updated via a rolling horizon framework with the hope of cost reduction by means of special-purpose packages or heuristics (Karimi et al. [8] ). ...
This paper presents mathematical modeling of joint lot sizing and scheduling problem in a job shop environment under a set of realistic working conditions. One main realistic assumption of the current study is dealing with flexible machines able to change their working speeds, known as process compressibility. The production schedules should be subject to limited available time in every planning period. Also, the model assumes that periodical sequences should be determined in a way that they obey from a fixed global sequence. Another complicating aspect of the problem is about consideration of precedence relationships for the needed processes of an item type over the corresponding machines. As the problem is proved to be strongly NP-hard, it is solved by a particle swarm optimization (PSO) algorithm. The proposed algorithm is self-controller about its working parameters, time to stop the search process, search diversification/intensification, and totally about its behavior. Performance of the algorithm is verified in terms of optimality gap using Lingo 11.0 on a set of randomly generated test data.Graphical abstractKeywordsLot sizingSchedulingProcess compressibilityJob shopParticle swarm optimization (PSO)Self-adaptivity
... An integrated approach for material planning and finite operation scheduling (IMPOS) was presented by (Fallah, 2002). The approach assumes the existence of a system that provides a relative priority measure for customer orders, based on a predetermined set of factors including -but not limited to -due dates. ...
We describe services that rate the performance of charitable organizations in the United
States as a potential source of data for comparisons by donors and may be of interest and
use to researchers. Such services have the potential to be considered as a surrogate for
quality metrics in the nonprofit sector. The three services considered, The American
Institute of Philanthropy, Charity Navigator, and the Wise Giving Alliance of the Better
Business Bureau, create different rating schemes. Statistical analyses of a dataset
comprised of charities in the Nonprofit Times Top 100 clarify points of similarity and
difference among the services. We conclude with several cautions for researchers
interested in pursuing further research in this area.
This paper studies simultaneous lot sizing and scheduling problem in a job shop environment over a finite number of periods. The machines are flexible such that the production manager is able to change their working speeds. Also, the production schedule of the items over machines should be in consistence with technological precedence relationships. The problem is formulated as an integer linear program. Then, a number of valid inequalities are developed based on the problem structures. The proposed valid inequalities are added to the problem formulation in a “cut and branch” manner to accelerate the search process by common solvers. Finally, performance of the valid inequalities is investigated with CPLEX 12.2 on a set of randomly-generated test data.
Capacity management is the planning and leveling of resources required (load) against the resources available (capacity). In this study, the lot size models used by Material Requirements Planning (MRP) had a major effect on the work center load profiles generated by Capacity Requirements Planning (CRP). Therefore, the selection of lot size models for MRP systems is an important decision for capacity management as well as materials management.
The results of this study highlight the operating characteristics of specific lot size models considering setup, inventory carrying, and capacity associated costs. For example, the Economic Order Quantity model and the Lot‐For‐Lot model in certain situations can help level load. The Periodic Order Quantity and Least Total Cost models especially for high cost structure ratios tend to result in erratic and lumpy work center load profiles. The reasons for such operating behavior are examined. Other concepts and relationships important to capacity management are discussed.
This paper considers the gap between scheduling theory and scheduling practice. The development and the main results of classical scheduling theory are reviewed and presented in an easily accessible way. Recent trends in scheduling research which attempt to make it more relevant and applicable are described. The nature of the gap between theory and practice is discussed. The failure of classical scheduling theory to address the total environment within which the scheduling function operates is noted. However, scheduling research in operations management and manufacturing systems tends to ignore the rich vein of methods, techniques and results in the classical theory. The need for an integrated scheduling research effort, containing elements of both approaches, is stressed.
This paper discusses the general framework of a methodology for material planning and operations scheduling. The methodology is designed to individually schedule customer orders according to the relative priority values assigned to each order, based on various factors including but not limited to due-dates. Resource constraints are considered during the scheduling process to ensure the feasibility of the finite production schedule, while attempting to ensure a reduced production lead time. The methodology is exemplified through test problems compared with the normal approaches. The preliminary results are quite promising, although further mathematical proofs are required to establish the potential advantages of the method in a generic form.
We address two infrequently studied problems in scheduling research, i.e. the problems of dynamic scheduling and integration of a job shop and its environment. A dynamic scheduling framework is presented in which dynamic scheduling is carried out through solving a series of static backward scheduling problems. The framework facilitates the integration by establishing the relationship between scheduling, due-date assignment and job release times through backward scheduling. A rolling time window approach is adopted to decompose the scheduling problem in time dimension and accommodate the dynamic conditions in a job shop.
This study develops a framework for analysing time-based competition and examines four supply-chain management strategies in make-to-order markets which can lead to cycle-time reduction: cross-functional product design participation, ‘just-in-time’ purchasing systems with suppliers, improved supplier delivery and quality performance, and work-in-process lot size reduction. A structural model and relevant measures were developed to assess the impact of these strategies on time-based competition, and the model was tested using interview data with managers in 40 plants from nine industries. Both just-in-time purchasing and supplier performance were found to have a significant effect on leadtime competitiveness, while cross-functional design and lotsize reduction did not. Several explanations for the lack of significance of the latter two variables were suggested based on qualitative observations and post-hoc analysis. Although the analysis suggests that the greatest progress towards time-based competitiveness can be made in the area of procurement of materials, the study points to the importance of managing the entire supply chain to attain this strategic advantage.
Rapid changes in the market environment, customer demands and technological advancement all cause the traditional, closed-loop MRP approach to lose efficiency. This paper suggests a solution for companies in which an end product of the same quality can be produced in different ways. In such an environment changes could be accommodated by an extended (multi) bill of material. The present solution is based on the hypergraph approach for modelling and optimizing multi-bills of material in the MRP system, and achieves cost reduction while maintaining the quality and service levels required by the company.
This paper presents the findings on how Hong Kong manufacturers use computer-based information systems for production planning and control. The local scene is characterized by original equipment manufacturing (OEM) business. The results of empirical surveys on the use of computer-based information systems are presented and elaborated. It was found that the behavior of the manufacturers is revealed in their expectations and attitudes about the use of decision support systems for production planning and control. As experience grows, a local manufacturer tends to organize its own way of systems efforts. Finally a conclusion is drawn about Hong Kong manufacturers' desire towards CIM projects.
This paper presents an integrated approach to production scheduling and materials
requirements planning. It discusses existing techniques and suggests how the new method
can overcome certain deficiencies. The method is incorporated in a computer program, and
sample outputs for an example problem are given. Some industrial experience is reported.
In a Materials Requirements Planning (MRP) system, component lead times are generally assumed to be known and constant. Since a requirement of a MRP system is that components finish on time, slack is often built into component lead times to insure that actual job flowtimes equal planned job lead times. In this study, job characteristics and shop characteristics are investigated to determine which has a greater impact on predicting job flowtimes. This is accomplished by determining which characteristic most greatly influences the deviation of planned job lead times from actual job flowtimes. After identifying those factors which have the greatest influence on the job's flowtime, due date assignment rules are developed. A simulation study is then made to determine. which of the due date assignment rules perform best for varying product structures, as defined by various Bills of Materials (BOMs), and various shop conditions. Simulation test results are presented and discussed.
This paper introduces an easy alternative to the Wagner-Whitin backorder algorithm. The algorithm is described and illustrated with an example. Its performance is compared with several of the traditional lot-sizing rules (lot for lot, economic order quantity, period order quantity, least unit cost, least total cost, part period algorithm, Silver-Meal algorithm and Wagner-Whitin algorithm) as well as the backorder versions of Wagner-Whitin and economic order quantity. This comparison is conducted using four different demand streams and 25 combinations of carrying, ordering and shortage costs. An aggregate performance index has been defined to compare lot-sizing rules. It is concluded that this new algorithm is sufficiently robust and relatively easy to apply. Results of experiments conducted highlight the more general nature of the backordering algorithms. By choosing the right combination of costs, backordering can be suppressed and traditional lot-sizing behaviour can be imitated
An essential condition necessary for the implementation of the Japanese just-in-time (JIT) technique with Kanbans is Small setup times relative to processing times. Without this condition bottlenecks occur at workcentres which delay production. However, the Japanese have developed a variation of the strict JIT technique that employs a special type of Kanban, referred to as a ‘signal Kanban’, at workcentres with relatively high setup times. While a normal Kanban triggers the production of larger than normal lots this altered version of the JIT technique provides an alternative approach for firms that desire to use the JIT technique, but are unable to reduce setup times at all workstations. The purpose of this paper is to describe the signal Kanban technique and demonstrate two versions of an integer mathematical programming approach for determining the optimal lotsizes to be used in conjunction with signal Kanbans. A simulation model is subsequently employed to test the effectiveness of the integer programming models and to explore some of the characteristics and conditions a firm might encounter when implementing a JIT system.
There is a widely perceived gap within the domain of scheduling for manufacturing systems, namely, many of the methods employed by production supervisors are quite different from those developed by researchers. In a sense, this inconsistency highlights the important fact that much scheduling research has failed to win approval where it matters most, namely, within the manufacturing system.
In this article, we argue for a practical approach to scheduling for manufacturing systems, one that we believe can narrow, and possibly bridge, the gap between theory and practice. This approach is based upon a well-defined and modular architecture for scheduling, termedproduction activity control. This architecture is the foundation of our proposed solution to scheduling, since it provides a coherent blueprint for the synthesis of information technology and scheduling strategies. The result of this synthesis is a design tool for production activity control, which allows for detailed and disciplined experimentation with a range of scheduling strategies in a controlled and simulated environment. Due to the unique modular property of the design tool, these strategies may then be implemented live in a flexible manufacturing facility, hence narrowing the gap between scheduling theory and manufacturing practice. Our overall approach is tested through an appropriate implementation in a modern electronics assembly plant.
We attempt to present in this paper a critical review of a particular segment of scheduling research in which the due to date assignment decision is of primary interest. The literature is classified into the static and dynamic job shop situations. The static job shop is analyzed from two different perspectives: the due date is constrained to be greater than or equal to makespan, and the optimal due date and optimal sequence are to be determined when the method of assigning due dates is specified. The literature on dynamic job shops is also reviewed under two broad categories. First, we discuss all the literature concerned with comparative and investigative studies to identify the most desirable due date assignment method. Second, we discuss the literature dealing with determination of optimal due dates. We note that computer simulation and analytical methods are two common approaches for the second type of problems. We observe that while the static single-machine problem with constant or common due dates has been well researched, very little or no work has been done on the dynamic multi-machine problem with sophisticated due date assignment methods. Finally, we identify and suggest some worthwhile areas for future research.
Existing approaches in Japan and western countries to managing production orders are surely different. The former aims at assuring a ‘lean production’ so that items can flow without waste, where each manufacturing stage ‘pulls’ the supply of items and resources according to its own needs from stages upstream. The latter forces management to plan ‘fat production’, so that the risk of stockout can be minimized and where the loading conditions at each stage have to be ‘pushed’ by a suitable plan. Besides different work organization in plants managed by ‘push’ or ‘pull’ philosophies the goals and aims of these two approaches are complementary. This fact raises the question of taking the opportunity to integrate these two philosophies, and to originate a new production management methodology able to handle difficult economic periods through robust planning, and to track markets in equilibrium through decentralized control. The question approached in this paper is: does an, at least theoretical, integration of the two approaches exist? This contribution aims to propose an answer in terms of the potential integration of the two approaches, as suggested by the different but complementary experiences of the two authors.
Production planning and control (PPC) is of great importance for the competitive position of manufacturing firms. For over thirty years a large number of computer assisted PPC systems have been on offer, most of them based on the well-known MRP logic. Since these systems often lead to unsatisfactory results, a number of new concepts for PPC systems have been developed. In this paper we first describe the traditional PPC concept and its critique, then we review the new PPC concepts which are available for practical application (workload control, MRP II, OPT, JIT-Kanban, progressive figures) together with OR models which are relevant to these new concepts.
This paper examines critically the role that Operational Research has played in developing production schedules at the aggregate, product, component, and operational levels. It concludes that some areas and problems are more receptive than others. Analytic techniques may be appropriate, where model conditions can be defined with reasonable certainty, and problem size is limited, but otherwise the emphasis is on developing flexible, integrative, and robust scheduling systems that provide the correct balance between (centralised) planning and shopfloor production control. At the same time, it is clear that other disciplines can contribute, and the position of OR with respect to Materials Requirements Planning and Just-in-Time Production is explored. Since the topic is a vast one, discussion is confined to mainstream scheduling activities and the interface between theory and practice.
This paper presents an interactive due date management system for controlling a job shop operation. The system is a simple procedure for setting attainable due dates for a job. The proposed system can be used interactively by a production manager to set up alternative schedules whilst allowing for different priority scheduling rules under various production capacity levels.
Over the past thirty years three main approaches for controlling the flow of materials, both into and through manufacturing organisations have been developed. Numerous papers exist which compare Material Requirements planning (MRP), Just-In-Time (JIT) and Optimised Production Technology (OPT), in an attempt to establish which is best. However, it is becoming increasingly apparent to both academics and industrialists that each of the above methods can make a positive contribution to the performance of the organisation if adopted. Research suggests that MRP, JIT and OPT, are in fact quite complementary and an outline framework for their integration is presented in the first part of this paper. Using computer simulation the authors examined aspects of the OPT philosophy and some preliminary results of this work are presented. These suggest that taking account of bottleneck resources when scheduling impacts favourably on performance. In conclusion it is argued that bottleneck scheduling could be the first step in developing an integrated approach to materials control.
This contribution focuses on some interesting phenomena occurring in scheduling capacity constrained resources in time-constrained situations. The scheduling situations considered form part of a simulation game developed to assist in teaching the scheduling philosophy of Optimized Production Technology (OPT) to production managers. It is shown that under certain conditions on set-up and processing times, advanced examples may be constructed combining three of the four complicating conditions mentioned m the OPT-literature. In addition, some interesting properties of process batches yielding a maximum throughput in such cases is considered.
An extended bill of material model for selecting production alternatives in a multi-routeing environment Addressing the gap in scheduling research: a review of optimisation and heuristic methods in production scheduling
- K Kogan
- B L Maccarthy
- J Liu
- K N Mckay
Kogan, K., 1994, An extended bill of material model for selecting production alternatives in a multi-routeing environment. International Journal of Production Research, 32, 657±667. MacCarthy, B. L. and Liu, J., 1993, Addressing the gap in scheduling research: a review of optimisation and heuristic methods in production scheduling. International Journal of Production Research, 31, 59±79. McKay, K. N., 1992, Production Planning and Scheduling: A model for Manufacturing Decisions Requiring Judgement. PhD thesis, University of Waterloo, Canada.
A ®nite capacity planning and scheduling approach with improved lead time over MRP
- H Fallah
- E Shayan
Fallah, H. and Shayan, E., 1995, A ®nite capacity planning and scheduling approach with improved lead time over MRP. Proceedings of the 6th ICME, Melbourne, Australia, pp. 303±310.
An integrated production planning and ®nite scheduling approach with reduced lead time ee ects
- H Fallah
Fallah, H., 1996, An integrated production planning and ®nite scheduling approach with reduced lead time ee ects. PhD thesis, Swinburne University of Technology, Melbourne, Australia.
A simulation study of bottleneck scheduling A mathematical programming approach for determining workcenter lotsizes in a Just In Time system with single Kanbans The Fundamental of Decision Making and Priority Theory with the Analytic Hierarchy Process
- A D Neely
- M D Byrne
- ±
- P R Phillipoom
- L Rees
- B Taylor
- P Huang
Neely, A. D. and Byrne, M. D., 1992, A simulation study of bottleneck scheduling. International Journal of Production Economics, 26, 187±192. Phillipoom, P. R., Rees, L., Taylor, B. and Huang, P., 1990, A mathematical programming approach for determining workcenter lotsizes in a Just In Time system with single Kanbans. International Journal of Production Research, 28, 1±15. Satty, T., 1994, The Fundamental of Decision Making and Priority Theory with the Analytic Hierarchy Process, Vol VI, AHP Series (RWS Publishers).
New concepts for production planning and control
- G Zapfel
- H Misbauor
Zapfel, G. and Misbauor, H., 1993, New concepts for production planning and control. European Journal of Operations Research, 67, 297±320. 4304 IMPOS Downloaded by [University of Sussex Library] at 22:47 14 January 2015
Production scheduling: practice and theory Survey of scheduling research involving due-date determination decisions A comparison of MRP lot sizing methods considering capacity change costs
- G Buxey
- ±31 Cheng
- T C E Gupta
Buxey, G., 1989, Production scheduling: practice and theory. European Journal of Operations Research, 39, 17±31. Cheng, T. C. E. and Gupta, M. C., 1989, Survey of scheduling research involving due-date determination decisions. European Journal of Operational Research, 38, 156±166. Collier, D. A., 1980, A comparison of MRP lot sizing methods considering capacity change costs. Journal of Operations Management, 1, 23±29. Dauzere-Peres, S. and Lasserre, J. B., 1994, An Integrated Approach in Production Planning and Scheduling (Germany: Springer-Verlag).
Antecedents of lead time competitiveness in make-to-order manufacturing ®rms Scheduling based MRP: an integrated approach to production scheduling and material requirements planning
- R B Handfield
- R T Pannesi
- N A J Hastings
- P H Marshall
- R J Willis
Handfield, R. B. and Pannesi, R. T., 1995, Antecedents of lead time competitiveness in make-to-order manufacturing ®rms. International Journal of Production Research, 33, 511±537. Hastings, N. A. J., Marshall, P. H. and Willis, R. J., 1982, Scheduling based MRP: an integrated approach to production scheduling and material requirements planning. Journal of the Operational Research Society, 33, 1021±1029.
SBMÐSchedule Based Manufacturing Australian Conference on Manufacturing Engineering Improving MRP and JIT compatibility by combining routings and bill of material Lot sizing procedure for requirements planning system: a framework for analysis
- References Barker
- J R Adelaide
- Australia
- J H Blackburn
References Barker, J. R., 1993, SBMÐSchedule Based Manufacturing. Australian Conference on Manufacturing Engineering, Adelaide, Australia. Blackburn, J. H., 1985, Improving MRP and JIT compatibility by combining routings and bill of material. Proceedings of the American Production and Inventory Control Society, Washington, US, pp. 444±447. Berry, W. L., 1972, Lot sizing procedure for requirements planning system: a framework for analysis. Production and Inventory Management Journal, No. 13, 19±34. Browne, J., Harhen, J. and Shivnan, J., 1996, Production Management Systems: an Integrated Perspective (UK: Wesley).
ARMOR: an application package for processes and assembly manufacturing which combines MRPII, PERT/CPM, and Just-In-Time functions into one system
- E R A Woxvold
Woxvold, E. R. A., 1993, ARMOR: an application package for processes and assembly manufacturing which combines MRPII, PERT/CPM, and Just-In-Time functions into one system. PhD thesis, Swinburne University of Technology, Melbourne, Australia.