Showing papers in "International Journal of Production Research in 1982"
TL;DR: A review of the state of the art in the study of dispatching rules can be found in this paper, where a dispatching rule is used to select the next job to be processed from a set of jobs awaiting service.
Abstract: This paper reviews recent studies of dispatching rules. A dispatching rule is used to select the next job to be processed from a set of jobs awaiting service. The paper has two objectives. The first is to discuss the state of the art in the study of dispatching rules. The discussion includes analytical approaches, simulation techniques and evaluation criteria. The second objective of the paper is to compare several of the dispatching rules listed in the Appendix using the results of recently published studies. It is impossible to identify any single rule as the best in all circumstances. However, several rules have been identified as exhibiting good performance in general.
967 citations
TL;DR: A comprehensive review of the various approaches that have been adopted in an attempt to solve the problem of forming machines into groups and components into associated families in Group Technology can be found in this article.
Abstract: The paper provides a comprehensive review of the various approaches that have been adopted in an attempt to solve the problem of forming machines into groups and components into associated families in Group Technology, A new and more efficient version of the previously published ROC algorithm, implemented interactively, is described together with a new relaxation procedure for bottleneck machines.
695 citations
TL;DR: In this article, the authors studied the ability of the IOBPCS to recover from shock demands, and to protect the manufacturing process from random variations in consumption, and showed that the feedback path is of fundamental importance in good control, and that adequate performance cannot be obtained by feedforward alone.
Abstract: In an inventory and order based production control system (IOBPCS), there are three fundamental system parameters. One of these, the production delay time, is beyond the control of the IOBPCS designer. Indeed, the production delay may be highly variable with time due to a variety of problems commonly found in manufacturing industry. This uncertainty must be countered by the proper use of a feedback loop which detects and operates on inventory deviations. The IOBPCS designer is thus left with the forward path demand averaging time and feedback path gain to adjust, as best he can. This paper studies the ability of the IOBPCS to recover from shock demands, and to protect the manufacturing process from random variations in consumption. It is shown that the feedback path is of fundamental importance in good control, and that adequate performance cannot be obtained by feedforward alone. Dynamic recovery is examined graphically by separately identifying the feedforward and feedback components. Random di...
327 citations
259 citations
TL;DR: An experiment is presented which shows the performance of a number of heuristics in the form of dispatching disciplines under different scheduling conditions which are determined by the scheduling period and the level of uncertainty in the process times and machine breakdowns.
Abstract: This paper presents a job scheduling problem. Two important aspects are included in the subsequent analysis. The first is the dynamic nature whereby new jobs arrive to be included intermittently through time. The second is the uncertainty, or error in estimating process times, and the likelihood of machine breakdown. An experiment is presented which shows the performance of a number of heuristics in the form of dispatching disciplines under different scheduling conditions which are determined by the scheduling period and the level of uncertainty in the process times and machine breakdowns. Various different measures of performance which could be of importance to management are considered. These include mean ratio of flow time to process time, mean queueing time, mean lateness, percentage of jobs late and net CPU times required to generate schedules in the simulation process. Results are presented showing the relationship between the performance of the heuristics relative to the different measures...
104 citations
TL;DR: In this paper, the authors deal with the minimization of an objective function which incorporates two conflicting criteria; cost minimization and closeness rating maximization, for facilities design problems, and a heuristic approach is developed which takes an initial layout and improves it step by step using a pairwise exchange routine.
Abstract: This paper deals with the minimization of an objective function which incorporates two conflicting criteria; cost minimization and closeness rating maximization, for facilities design problems. The objective function represents the difference of materials handling cost and the closeness rating with predefined weights assigned to both criteria. A heuristic approach is developed which takes an initial layout and improves it step by step using a pairwise exchange routine.
94 citations
TL;DR: In this paper, the authors present a survey and classification of production planning models according to their orientation (descriptive and normative models) and according to scope (aggregate planning models, functional interface models, and hierarchical models).
Abstract: This paper surveys and classifies production planning models introduced in the literature according to their orientation (descriptive and normative models) and according to scope (aggregate planning models, functional interface models, and hierarchical models). Each of these categories is then sub-classified, by the type of formulation followed and solution method used, into exact and heuristic methods. For each of these classes of models, its characteristics, usages and limitation are discussed. The relationship between the descriptive and normative models is analysed with illustrative examples from the industrial sector in the U.S.A. and Egypt The paper concludes by identifying major gaps in current theory of production planning on the one hand, and between theory and practice on the other hand, suggesting positive steps, and schemes of action for closing these gaps.
66 citations
TL;DR: In this article, the authors developed a model which can be used to make an economic evaluation of alternative configurations of robots which could be used in the same production system, considering the time value of money, the uncertainty of time in technological development and of inflation.
Abstract: This paper develops a model which can be used to make an economic evaluation of alternative configurations of robots which could be used in the same production system. The model considers the time value of money, the uncertainty of time in technological development and of inflation. The structure of the model allows a high degree of flexibility between significantly different accounting systems. The emphasis is not on producing absolute coat values, but rather on the Production Engineer making the right choice of a system.
59 citations
TL;DR: In this article, the standard deviation of the quantity received is taken to be independent of, or proportional to, the quantity ordered, and the results obtained are shown to be extensions of the well known results of the simple lot size model with backordering.
Abstract: In most economic lot size models, the demand during stockout period is either completely backordered, or lost. Also, the quantity received is assumed to be the same as the quantity ordered. In this paper, a lot size model is described in which the demand during stockout period is either completely or partially backordered, and also the quantity received is uncertain. The standard deviation of the quantity received is taken to be independent of, or proportional to, the quantity ordered. In both cases, the results obtained are shown to be extensions of the well known results of the simple lot size model with backordering.
57 citations
TL;DR: A mathematical model based on the branch-and-bound technique to solve static scheduling problems involving n jobs and m machines where the objective is to minimize the cost of setting up the machines is presented.
Abstract: This paper presents a mathematical model based on the branch-and-bound technique to solve static scheduling problems involving n jobs and m machines where the objective is to minimize the cost of setting up the machines. Set-up times are sequence dependent and not included in processing times. There is a finite non-zero cost associated with setting the machines which is different for each machine. It is further assumed that the routing may be different for different jobs and a job may return to a machine more than once.
56 citations
TL;DR: In this paper, a generalization of the well-known "sawtooth" inventory control model which is used to determine optimal policies for stocking a single item under certain conditions is considered.
Abstract: We consider a generalization of the well-known ‘sawtooth’ inventory control model which is used to determine optimal policies for stocking a single item under certain conditions. The case where several items are to be stocked simultaneously and subject to a number of constraints give rise to the generalization that is of interest. We show that the problem of analysing the model may he viewed as a problem in posynomial Geometric Programming. We then point out some of the advantages to be realized from viewing it this way and from using Geometric Programming techniques to solve it. These include, the ability to obtain feasible solutions with known upper bounds on the difference between their associated costs and the minimum cost, a capability for performing an analysis of the sensitivity of the values of the optimized parameters to variations in input parameters, availability of a solution method that is computationally more attractive than methods previously known and, arising out of this last ben...
TL;DR: The paper presents computational experience with the algorithm for a variety of randomly generated test problems (up to 50 jobs and 50 machines in size), and compares its performance with other published heuristic techniques.
Abstract: This paper describes a heuristic procedure for sequencing the n job m machine static flowshop. Basically, the procedure is performed in two overall steps. In the first step, each of the n jobs is tested as a potential immediate follower to each of the other jobs. In effect, this step of the procedure asks the question, ‘how well does a particular job fit in terms of job blocking or machine idleness if it were to follow some other job?’ An overall figure of merit, or cost cij, is determined for each job j as a follower to another job i. Six different heuristics are presented for determining sets of cij values. Using these values of cij, the second step then heuristically develops a job sequence by solving the travelling salesman problem. The paper also presents computational experience with the algorithm for a variety of randomly generated test problems (up to 50 jobs and 50 machines in size), and compares its performance with other published heuristic techniques.
TL;DR: Comparisons of the project durations using the above criteria with those of GENRES, ACTIM, ACTRES, and TIMRES show that ROT-ACTIM and GENRES prove to be superior to other criteria.
Abstract: This paper presents heuristic algorithms for project scheduling and resource constraints. ROT, ROT-ACTIM, and ROT-ACTRES are three different criteria which are utilized in finding the minimum project duration under resource constraints. Comparisons of the project durations using the above criteria with those of GENRES, ACTIM, ACTRES, and TIMRES show that ROT-ACTIM and GENRES prove to be superior to other criteria.
TL;DR: An algorithm is developed for the analysis of the traffic behaviour in the recirculating conveyor with stochastic inputs and outputs through the theory of conveyor systems as ordered entry queueing systems, extended to include models with recirculation.
Abstract: An algorithm is developed for the analysis of the traffic behaviour in the recirculating conveyor with stochastic inputs and outputs. The approach is through the theory of conveyor systems as ordered entry queueing systems, extended to include models with recirculation. The analysis of overflow traffic from loss models and the superposition of two general point processes combine to yield an approximation for the first two moments of the processes on both the outward and inward cycles of the conveyor. A simulation model of the conveyor is also developed. A comparison of the simulation with the algorithm not only indicates the accuracy of the algorithm, but points out the inherent shortcomings of the simulation approach. This effect is dramatized as the value of the traffic intensity is increased.
TL;DR: The main thrust of this research effort is to define the critical problem areas encountered while taking an analytical approach and a simulation model in SEMSGRJ PT 1 I'd has been developed for the purpose of the research.
Abstract: Group Technology (GT.) is a management concept which adequately serves the purpose of increasing the productivity of a small batch producer. Since its inception, the concept has progressively grown from a technique to a philosophy and its impact- on the different limbs of the organization structure is now being recognized. Companies that have adopted G.T. claim significant reductions in throughput times and costs. But analytical research on G.T. is lagging behind its industrial application The main thrust of this research effort is to define the critical problem areas encountered while taking an analytical approach. A simulation model in SEMSGRJ PT 1 I'd has been developed for the purpose of the research. The effect of the important variables on the performance of a G.T. shop is demonstrated with the help of this model. The model is intended to be general so that the significance of the different parameters and variables can be evaluated for several manufacturing environments.
TL;DR: In this paper, a simple production system capable of producing many different products is examined by decomposing the problem into its major parts (carousel, work transporter, linking conveyors and the work stations) and then using the results to compute overall system performance.
Abstract: The extreme cases of production operations—the job shop and the progressive assembly line—are viewed as special cases of a single general production model. They differ only in time span and the number of possible production routes. The common elements of the extreme systems can be studied by analysing a recent production system innovation, the carousel-work-transporter system. In this paper a simple production system capable of producing many different products is examined by decomposing the problem into its major parts (carousel, work transporter, linking conveyors and the work stations) and then using the results to compute overall system performance. We introduce the concept of virtual inventory and show how systems with this property can be more productive than progressive storage systems. While the system can be analysed by using computer simulation models we use only analytic queue theory models to obtain approximate results.
TL;DR: In this article, the authors examined the abilities and limitations of combined utilization of humans, automation, conveyors and robots to improve the productivity of robots and automation while increasing work satisfaction and productivity for the humans.
Abstract: Seeking to improve work design, this study examines the abilities and limitations of combined utilization of humans, automation, conveyors and robots. The comparison leads to the objective of this analysis, of enhancing the productivity of robots and automation while increasing work satisfaction and productivity for the humans. Towards the goal of achieving this objective, consideration is given to the development of a framework for the selection of the appropriate robot, machine and conveyor to complement the human in a work environment. A case study is used to illustrate the usefulness and efficiency of the proposed approach to systems optimization.
TL;DR: In this paper, a mathematical model for milling operations is developed and the five primary control variables identified, which is then decomposed and an efficient optimization procedure developed for control variable identification.
Abstract: Although milling is one of the most common chip metal removal processes, little has been done to aid in identifying the optimum operational conditions for milling processes. In this paper, a mathematical model for milling operations is developed and the five primary control variables identified. The model is then decomposed and an efficient optimization procedure developed for control variable identification.
TL;DR: The authors know how to preplan simple and efficient flow systems and to achieve by this means major gains in both productivity and workers’ job satisfaction.
Abstract: There is a widely accepted philosophy of production organization which has provided the foundation for the design of nearly all the world's factories. It is based on a set of beliefs which until recently were never questioned. This philosophy provides restraints which make it difficult to increase efficiency. It inevitably produces very complex, material flow systems, makes it difficult to delegate responsibility for the completion of products or components and leads to highly bureaucratic systems with centralized decision making and a low level of job satisfaction. Since the Industrial Revolution we have learned to plan the production of components with some precision. Until recently we did not plan material flow systems; they only evolved as the results of thousands of independent component planning decisions. We now know how to preplan simple and efficient flow systems and to achieve by this means major gains in both productivity and workers’ job satisfaction.
TL;DR: In this paper, the authors present an overview of the state of the art in combining aggregate planning models with learning curve productivity considerations, and present a model that incorporates changing productivity factors into aggregate plans.
Abstract: Most aggregate planning models utilize a constant productivity factor throughout the planning horizon. Recently new work has been done to incorporate changing productivity factors into aggregate planning models; however, some of these models have certain limitations and unrealistic assumptions. The objective of this paper is to present an overview of the state of the art in combining aggregate planning models with learning curve productivity considerations.
TL;DR: In this paper, the authors present a systematic methodology based on Wight and Belt's ideas to characterize and analyse the flow of work through a work station, and relate this flow to the nominal capacity of the station.
Abstract: The central problem of manufacturing planning is to reconcile clue dates, derived from customer delivery timetables, with schedule dates, developed from production capabilities. Conventional capacity planning techniques utilize the technological sequencing of material flow in order to build up production schedules. As they ignore interactions between work stations, and override due date requirements, these techniques are often unsatisfactory. Wight and Belt have suggested a new approach to the problem, and this paper presents a systematic methodology based on their ideas, to characterize and analyse the flow of work through a work station, and relate this flow to the nominal capacity of the station. Operation of the station is measured by work in process, delay and underload (operation below nominal capacity); flow between stations is measured by queue length and lead times (process plus wait time). Performance is evaluated by the degree of underload and overload planned for the station—the degre...
TL;DR: In this article, a procedure is introduced in which selected jobs, initially programmed in a schedule at maximum production rates, hare their machining rates reviewed in order to reduce costs.
Abstract: Two alternative objectives when analysing machining rates are to produce components at maximum production rate or at minimum cost. Tn this psiper, a procedure is introduced in which selected jobs, initially programmed in a schedule at maximum production rates, hare their machining rates reviewed in order to reduce costs. An integrated manufacturing system with a job shop work pattern is assumed and in which due date criteria are applied to finished jobs. The cost reduction procedure is designed to operate while maintaining the original schedule performance.
TL;DR: In this paper, an exploratory study was undertaken in order to determine appropriate procedures for statistically analysing output from a stochastic simulation experiment, and three variance reduction techniques were investigated.
Abstract: An exploratory study was undertaken in order to determine appropriate procedures for statistically analysing output from a stochastic simulation experiment. Single level lot-sizing was studied in an environment with a fixed planning horizon, zero lead time, no forecast errors, and no initial inventories. Of special interest was the specification of factors such as length of the horizon, average time between orders, coefficient of variation related to demand, and number of observations. To achieve increased accuracy, three variance reduction techniques were investigated.
TL;DR: In this article, the authors examined the technological and operational factors that affect production planning and control in cotton spinning mills and presented a simulation model developed to assist in maintaining the balance of the production system by controlling inter-stage stocks.
Abstract: This paper examines the technological and operational factors that affect production planning and control in cotton spinning mills and presents a simulation model developed to assist in maintaining the balance of the production system by controlling inter-stage stocks. The production system is characterized by a series of stages with different numbers of parallel machines at each stage having batch input and output features. Statistical analysis of the results obtained are discussed.
TL;DR: In this paper, the effect of two issuing policies, LIFO and FIFO, on the inventory level in a production lot size model for items with varying rate of deterioration is studied.
Abstract: The effect of two issuing policies, LIFO and FIFO, on the inventory level in a production lot size model for items with varying rate of deterioration is studied An implicit form of inventory level under each policy is developed for each phase of a cycle which is shown to be consistent with known extreme cases A numerical solution procedure employing the Runge-Kutta method and Simpson's Rule is developed to select a preferable policy in terms of the amount deteriorated per unit time.
TL;DR: In this paper, the problem of maximizing the long-run average return (reward rate) was formulated as two special semi-Markov decision processes and discussed a class of the control problem of stochastic production systems.
Abstract: Consider job-shop production under the conditions that orders arrive according to a Poisson process, processing time is dependent on the reward of the orders, production capacity is finite, and backlog is allowed. This paper distinguishes two simple order selection policies with a selection criterion (control variable), formulates the problem of maximizing the long-run average return (reward rate) as two special semi-Markov decision processes, and discusses a class of the control problem of stochastic production systems. By a numerical example, it is concluded that two simple policies: Static Selection Policy (SSP) and Sequential Selection Policy (SeSP) are alternative.
TL;DR: In this paper, a queueing network technique (Solberg's CAN-Q) and a flow control simulator (SINDECS) are applied to investigate general, fundamental performance properties of material flow systems (MFS).
Abstract: A queueing network technique (Solberg's CAN-Q) and a flow control simulator (SINDECS) are applied to investigate general, fundamental performance properties of material flow systems (MFS). The effects of a system's structure and flow logic on performance are compared for three typical flow systems: transfer line, recirculating conveyor loop, and job shop. The concepts of Most Economical MFS for a given performance level, Iso-Performance MTS combinations, and Overall MFS Configuration Measures are introduced.
TL;DR: In this paper, the authors report on research conducted to develop a simulation model which incorporates the basic MRP logic into the modelled production process and provide information necessary for planning and controlling of the material and capacity requirements of a production process that includes stochastic processes.
Abstract: The purpose of this paper is to report on research conducted to develop a simulation model which incorporates the basic MRP logic into the modelled production process. The objective of the modelling effort is to provide information necessary for planning and controlling of the material and capacity requirements of a production process that includes stochastic processes. The modelling and analysis procedure exploits the fact that the structure of the production process can be logically modelled as a network flow process. The technique employed to facilitate the network modelling is Q-GERT (Graphical Evaluation and Review Technique) modelling and simulation language. A case application is presented to demonstrate a prototype model, followed by a report of the simulation results. The model is designed to provide answers and insights to the following questions: (1) how long must each production centre operate to yield the specified quantities of finished products, (2) what is the expected lead time r...