Showing papers on "Job shop published in 1987"
TL;DR: The results indicate that the new rules are not only superior to competing rules for minimizing weighted tardiness penalties but are also robust for several other criteria, such as the number of tardy jobs and the costs of in-process inventories.
Abstract: Mainstream research in priority dispatching has considered jobs with equal delay penalties, thereby ruling out strategic differentiation of customer orders. We develop and test efficient dispatchin...
535 citations
TL;DR: In this paper, the COVERT job shop dispatching rule was examined in detail relative to its applicability, its sensitivity to various operating parameters and performance measures, and its performance compared to several other sequencing rules including truncated SPT rules, dynamic slack rules and modified duedate rules.
Abstract: The COVERT job shop dispatching rule was tested extensively twenty years ago with impressive results, however, since then it has been included in only one comparative analysis with other sequencing rules, and, reported instances of its application have been infrequent. In this paper, the COVERT rule is examined in detail relative to its applicability, its sensitivity to various operating parameters and performance measures, and its performance compared to several other sequencing rules including truncated SPT rules, dynamic slack rules and modified duedate rules. The performance of COVERT is examined for a variety of tardiness measures. The examination is conducted within the context of a simulation model of a machine-constrained job shop with serial jobs and random routings. The results indicate that COVERT performs well as a sequencing rule and in most instances was superior to the other sequencing rules tested both directly and across varying degrees of due-date tightness.
105 citations
TL;DR: The truncated repetitive lots (TRL) as mentioned in this paper scheduling procedure was proposed to improve the performance of traditional job shops by allowing no more than K jobs to be combined in a queue of waiting jobs.
101 citations
TL;DR: A well-organized traditional job shop may be able to achieve overall performance that at least is comparable to that of the same shop using cellular (group technology) layout.
Abstract: This study compares different strategies for arranging machines in a facility. Computer simulation of two different machine shops was used to compare process layout (the arrangement of groups of machines where the machines within a group are interchangeable) to cellular layout designed using group technology concepts (the use of manufacturing cells where each cell contains different types of machines dedicated to the production of similar parts). Four layout strategies, including process layout, cellular layout, and two hybrid layouts, were compared in two machine-shop models. The shops that used cellular layouts had shorter setup times, lower machine utilization, and shorter distances traveled, on average. The shops with process layout, however, had better performance on queue-related statistics such as work-in-process inventory level and average flow time. This suggests that a well-organized traditional job shop may be able to achieve overall performance that at least is comparable to that of the same shop using cellular (group technology) layout.
99 citations
01 Dec 1987
TL;DR: An heuristic algorithm is described to find a near optimal solution such that the bottleneck machines are fully utilized in steady-state with a minimal number of jobs in-process.
Abstract: This paper is devoted to the analysis of the job-shop scheduling and sequencing problem for a repetitive production process. An heuristic algorithm is described to find a near optimal solution such that the bottleneck machines are fully utilized in steady-state with a minimal number of jobs in-process. The developments are carried out using a modelling based on Timed Petri Nets.
36 citations
TL;DR: In this article, the authors integrate a quality control procedure into a job shop manufacturing process described by an M/M/1 queue and present an optimization problem for minimizing inspection and queueing related costs.
Abstract: The purpose of this paper is to integrate a quality control (inspection) procedure into a job shop manufacturing process described by an M/M/1 queue. Given a joint inspection and queueing system, an optimization problem for minimizing inspection and queueing related costs is formulated and resolved.
34 citations
TL;DR: In this article, a combined input/output control system is presented for periodically determining the set of jobs to be released (input variables) and the capacities of processing centers (output variables) in the dynamic job shop, so that a composite cost function is minimized.
Abstract: A combined input/output control system is presented for periodically determining the set of jobs to be released (input variables) and the capacities of processing centers (output variables) in the dynamic job shop, so that a composite cost function is minimized. An interactive heuristic optimizing algorithm incorporating a 0–1 linear mixed integer program is formulated. The resulting control system is compared by simulation with an alternate system for which only input is subject to control. Significant improvements are obtained for most performance measures evaluated.
34 citations
TL;DR: A design framework that embodies domain-specific knowledge used to support opportunistic reasoning and hierarchical organization structure used to control and coordinate problem-solving activity is proposed and used to develop a knowledge-based job-shop scheduling system.
Abstract: This paper discusses two principles that have become increasingly important in the design of knowledge-based systems: domain-specific knowledge used to support opportunistic reasoning and hierarchical organization structure used to control and coordinate problem-solving activity. We propose a design framework that embodies these two principles and describe how this framework has been used to develop a knowledge-based job-shop scheduling system. This system, called OPIS 0, has undergone limited testing in an experimental environment modeled after an actual job shop. Its performance has been very good compared to ISIS and to the more traditional approach of constructing a schedule by dispatching jobs using the COVERT priority rule. The resulting design also shows potential for use in a decision support role.
30 citations
TL;DR: In this paper, the results of a job shop computer simulation study were reported, in which jobs were made up of several parts, and where operations on the different parts can be going on at the same time in different machining centres.
Abstract: This paper reports the results of a job shop computer simulation study in which jobs were made up of several parts, and where operations on the different parts can be going on at the same time in different machining centres. Priority rules are evaluated in terms of average job flow time, and have been chosen mainly for their ability to coordinate the completion time of the various job parts. A rule based on the minimum remaining job time has been found to produce the best results. The paper also attempts to classify the various priority rules in terms of their operational significance.
26 citations
TL;DR: In this paper, the authors evaluate the use of cost information for establishing priorities in a job shop and evaluate several priority rules on the basis of time performance, primarily on-time completions, as well as cost performance: the minimization of WIP investment.
22 citations
TL;DR: In this paper, a job shop is modelled as an open queueing network of the Jackson Jackson, J. R. type, and two problems are studied: the loading of stations and the assignment of servers, respectively.
Abstract: Consider a job shop that is modelled as an open queueing network of the Jackson Jackson, J. R. 1957. Networks of waiting lines. Oper. Res.5 518-521. type. All work stations in the shop have the same number of parallel servers. Two problems are studied: the loading of stations and the assignment of servers, which are represented by loading and assignment vectors, respectively. Majorization and arrangement orderings are established to order, respectively, the loading and the assignment vectors. It is shown that reducing the loading vector under majorization or increasing the assignment vector under arrangement ordering will reduce the congestion in the shop in terms of reducing the total number of jobs in the sense of likelihood ratio ordering, the maximum queue length in the sense of stochastic ordering, and the queue-length vector in the sense of stochastic majorization. The results can be used to support production planning in certain job shops, and to aid the design of storage capacity.
TL;DR: In this article, a conceptual framework for the application of expert systems for the selection and development of scheduling rules for a job shop is presented, illustrated using an expert system developed using MI™.
01 Mar 1987
TL;DR: It is shown that delay is an important consideration in many manufacturing systems that are modeled as continuous flow processes and a scheduling policy for a job shop with delays is derived using theoretical arguments and heuristics.
Abstract: In this paper, the presence of delay in a job shop is addressed. We show that delay is an important consideration in many manufacturing systems that are modeled as continuous flow processes. A scheduling policy for a job shop with delays is then derived using theoretical arguments and heuristics.
Dissertation•
01 Jan 1987
TL;DR: In this article, three extensions to a previously published model which assists managerial planning in a multi-sector job shop are presented, which provides insight into the trade-off between two aspects of system behavior, production smoothing and size of work-in-process inventories, which will be affected by management's choice of production lead times.
Abstract: We develop three extensions to a previously published model which assists managerial planning in a multi-sector job shop [Graves, 1986]. This model provides insight into the trade-off between two aspects of system behavior, production smoothing and size of work-in-process inventories, which will be affected by management's choice of production lead times. For all three extensions we provide numerical examples of application. First, we develop a model of a production release rule which coordinates demand forecasts over a planning horizon with knowlege of the projected completion times of items currently in work-in-process inventory in order to determine the number of items to start into production. This release rule model is necessary in order to apply Graves' model to a production line which produces in response to demand forecasts rather than in response to order arrivals, as is typical of a job shop. Second, we develop two measures of the service level of a shop and show how these are affected by the choice of production lead times. The service measures considered are the probability that demand during a random period is met and average length of failure runs (by a failure run we mean several periods in succession during which the facility fails to meet demand). We discuss how management can evaluate the impact of lead time choice on the expanded set of trade-offs among service measures, production smoothing, and size of inventories. Third, we model the dynamic behavior of a shop in response to various types of change in demand. The changes considered are a one-period increase, permanent increase, linear growth, and cyclical demand. We show how to assess the time the system will take to achieve its new equilibrium and the nature of the path followed during the transition and how these responses depend upon lead time choices. These three extensions should enhance the usefulness of Graves' model by widening the scope of facilities to which it may be applied and by extending knowledge about the impact of lead time choices on additional important aspects of system behavior. Thesis Supervisor: Dr. Stephen C. Graves Title: Associate Professor of Management Science
TL;DR: It was found that the best place for the bottleneck machine to be located was at gateway operations located low in the Bill of Materials.
Abstract: In this paper, the authors investigate the effects bottleneck machines have on the performance of a multi‐stage job shop. The operation performed by the bottleneck and its position in the product Bill of Materials is varied to determine the effects on system performance. It was found that the best place for the bottleneck machine to be located was at gateway operations located low in the Bill of Materials.
TL;DR: In this article, a linear programming model is developed to find an optimal CON due date which is solved by considering its dual, and a procedure to find the optimal job sequence is then presented and elaborated by a numerical example.
Abstract: This paper considers the problem of finding an optimal CON due date and sequencing of n independent jobs to be processed on a single machine by minimizing the total value of lateness. A linear programming model is developed to find an optimal CON due date which is solved by considering its dual. A procedure to find the optimal job sequence is then presented and elaborated by a numerical example.
01 Jan 1987
TL;DR: In this paper, a computerized capacity planning system for the IBM Microcomputer family is presented, which maintains the profile of the job shop in a data base along with data pertinent to various products that can be manufactured in the shop.
Abstract: Presented here is a computerized capacity planning system for the IBM Microcomputer family. The system maintains the profile of the job shop in a data base along with data pertinent to various products that can be manufactured in the shop. Projected orders for the planning period are input to the system with their associated quantities and delivery dates. The system uses the forward and backward loading rules in generating capacity loading scenarios. User selects the best course of action which may satisfy delivery dates subject to the limitations of the work centers. Efficiency figures are provided to aid the user in his/her decision.
01 Jan 1987
TL;DR: The branch-and-bound procedure have been used to develop an interactive program in BASIC for finding the optimal job sequence for general three-machines flow shop problems.
Abstract: The order in which jobs pass through machines or work centres is a sequencing problem. The sequencing problems occur in flow shop as well as job shop production systems. In flow shop production systems, each job follows the same processing route whereas in the job shop production system, jobs flow across machines or work stations on many different routes. For optimizing the sequencing of such jobs, production planners may adopt different criteria such as makespan time, average completion time, due date performance, machine utilization and so forth. In the absence of given criteria, it is usual to accept the makespan time as the criteria and to attempt to minimize this. In a 2-machines flow shop, the jobs can be sequenced optimally for minimum total makespan time by using Johnson's algorithm [1]. Johnson's algorithm can also be used to find the optimal sequence for special three-machines flow shop problems satisfying certain conditions [1]. But for general three-machines sequencing problems, optimal sequence based on makespan time can be obtained by using a branch and bound solution procedure [1]. In this paper, the branch-and-bound procedure have been used to develop an interactive program in BASIC for finding the optimal job sequence for general three-machines flow shop problems. This program which is written for an IBM-PC or IBM-PC compatibles, also provides the time chart and the time chart drawing. Furthermore, it gives the results of the branching steps (i.e the partial sequences) in a tabular form.