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Showing papers on "Job shop published in 1988"


Book
01 Jan 1988
TL;DR: Introduction to Simulation types of Simulation and the Flow of Time Stochastic Simulation Discrete Simulation A Job Shop Model with Material Handling Simulation Software.
Abstract: Introduction to Simulation Types of Simulation and the Flow of Time Stochastic Simulation Discrete Simulation A Job Shop Model with Material Handling Simulation Software - An Overview Flexible Manufacturing Systems Building FMS Models - 1: Load-Unload Operations, Pallets, Machines Building FMS Models - 2: Machine Buffers and Central Pallet Storage Building FMS Models 3 - Operation Sequences, Fixtures and Tools Building Simulation Models 4 - Vehicles and Movement Durations Building Simulation Models 5 - Robots, Conveyors and AS/RS Systems On Simulation Projects Some Developments in Simulation.

192 citations


Journal ArticleDOI
TL;DR: An evaluation of five releasing mechanisms and four dispatching rules under various levels of aggregate due-date tightness, shop cost structure, and machine utilization using simulation to demonstrate the interactive nature of releasing and dispatching on shop performance.
Abstract: Controlling the flow of material on the shop floor involves releasing and dispatching jobs to meet customer due-date requirements while attempting to keep operating costs low. This report presents an evaluation of five releasing mechanisms and four dispatching rules under various levels of aggregate due-date tightness, shop cost structure, and machine utilization using simulation. The performance criteria of total shop cost, jobs on shop floor, deviation from due dates, and job queue time are collected to demonstrate the interactive nature of releasing and dispatching on shop performance.

178 citations


Journal ArticleDOI
TL;DR: In this paper, the authors examined the effect of load limits on the performance of a job shop in terms of flow time, inventory, and order tardiness, and concluded that load limits introduce idle time into the schedule.

86 citations


Journal ArticleDOI
TL;DR: In this paper, the authors developed approximations for the distribution of the total time spent in a dynamic job shop using an exponential limit theorem and an heuristic decomposition of open queueing networks.
Abstract: In this paper we develop approximations for the distribution of the total time spent in a dynamic job shop. In particular, using an exponential limit theorem and an heuristic decomposition of open queueing networks, we show that for a large class of dynamic job shops, the total time spent in a dynamic job shop can be approximated by an exponential random variable with an appropriate mean. Approximations for job shops that do not belong to this class are also developed. Numerical results show that the proposed approximations are in general very good. Application of these approximations in the assignment of due-dates is also illustrated.

82 citations


Journal ArticleDOI
TL;DR: In this paper, the authors show how the Kanban method may be adapted to the job shop and show that the adaptation is extensively tested through simulation and then implemented, and shows marked improvement over previous practice.
Abstract: Japanese industrial management techniques have been applied in a large number of large Western enterprises. In particular, the Kanban method has been used to control materials, production rate and volume, and to adjust production to requirements. The authors show how the Kanban method may be adapted to the job shop. This adaptation was extensively tested through simulation and then implemented. Actual performance is consistent with the simulation results, and shows marked improvement over previous practice.

81 citations


Journal ArticleDOI
TL;DR: In this paper, the authors considered an n-jobs one machine sequencing problem in which all jobs have a common due date and a deviation in their completion time occurs when a job is completed before or after the common date.
Abstract: In this paper we consider an n jobs one machine sequencing problem in which all jobs have a common due date and a deviation in its completion time occurs when a job is completed before or after the common due date. The objective is to find an optimal value of this common due date and a corresponding optimal sequence such that the mean absolute deviation of the completion times of the jobs in the optimal sequence from the corresponding optimal common due date is at its global minimum. Starting with an arbitrary sequence we relate the problem to a generalized linear goal program from which some basic results are proved using elementary properties of linear equations and a linear goal programming problem. Using these results and the idea of sensitivity analysis in linear programming, an algorithm is developed that determines the optimal due date and the corresponding optimal sequence yielding the global minimum value of the mean absolute deviation of the completion times of the jobs in the optimal s...

43 citations


Journal ArticleDOI
TL;DR: The Leontief Input-output model and linear programming are used to determine performance measures of a flexible manufacturing system for the economic Justification of the system.
Abstract: The Leontief Input-output model and linear programming are used to determine performance measures of a flexible manufacturing system for the economic Justification of the system. The performance measures Include: the total number of units processed within a specified time interval at each machining center: the number of acceptable components produced within a given time interval: and the average number of transfers between machining centers for each component. The first two performance measures are used to estimate the productivity of the system and the costs associated with scrap. The third performance measure is used to estimate material handling time and costs. These performance measures are then used as inputs to the Analytic Hierarchy Process for the economic Justification of the flexible manufacturing system. An example of a Job shop system and two alternative flexible manufacturing systems is given to illustrate the methodology.

29 citations


Journal ArticleDOI
TL;DR: This paper presents an approximate algorithm based on a capacitated transshipment formulation that provides a feasible solution along with its error bound and is implementable in terms of both speed and accuracy.
Abstract: This paper addresses the problem of simultaneously determining overtime utilization and job sequencing over a finite planning horizon in a single machine job shop environment. Shipping times are assumed to occur at fixed and specified points in time, and their number is much smaller than the number of jobs. The goal is to find an overtime utilization level and job sequence that yields a "good" tradeoff between overtime cost and tardiness penalties. We begin by showing that the problem in its simplest form is NP-hard. We then present an approximate algorithm based on a capacitated transshipment formulation. This approximation provides a feasible solution along with its error bound. The algorithm is refined by incorporating the dominance relations of jobs. Extensive computational experience indicates that the algorithm is implementable in terms of both speed and accuracy.

28 citations


Book ChapterDOI
01 Oct 1988
TL;DR: Production management is defined as the planning and control of all activities necessary to produce a set of products to support metalworking job shop type companies.
Abstract: Production management is defined as the planning and control of all activities necessary to produce a set of products. For a typical metalworking job shop type of company, production management thus comprises important functions such as: Product development and technological planning Production planning and control Materials planning and control Quality assurance Cost engineering.

27 citations


Journal ArticleDOI
TL;DR: In this paper, a semi-local due-date-oriented dispatching rule is designed which is able to monitor the progress of jobs closely, and the performance of the rule is enhanced by a rational due date assignment procedure which takes account of both job content and shop status information in determining due-dates.
Abstract: A simulation study to investigate the effect on missed due-dates and job flow-time is discussed by combining the job dispatching and due-date assignment decisions in job shop scheduling. A ‘semi-local’ due-date-oriented dispatching rule is designed which is able to monitor the progress of jobs closely. The performance of the dispatching rule is enhanced by a rational due-date assignment procedure which takes account of both job content and shop status information in determining due-dates. The simulation results show that the combined scheduling procedure performs better than some common simple dispatching rules which are used with the total-work-content (TWK) due-date assignment method.

26 citations


Journal ArticleDOI
TL;DR: This paper considers the maintenance of an unreliable M/G/1 queue-like job shop, integrating the maintenance process and the resulting queue operating characteristics and basic results regarding the queue-maintenance policy are established.
Abstract: This paper considers the maintenance of an unreliable M/G/1 queue-like job shop, integrating the maintenance process and the resulting queue operating characteristics. The system may breakdown, leading to unscheduled maintenance. Otherwise, preventive maintenance is done whenn jobs have been processed — whichever comes first. Using arguments from renewal theory, basic results regarding the queue-maintenance policy are established. Both an analytical and numerical example are studied in detail.

ReportDOI
01 Jan 1988
TL;DR: Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1988.
Abstract: Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1988.

Journal ArticleDOI
TL;DR: The objective of the truncated SI rules was to improve upon the tardiness problem associated with the simple SI rule without worsening greatly the good performance of SI on job flowtimes.

Journal ArticleDOI
TL;DR: This paper addresses the problem of open order rescheduling in a job shop by modeled to include several realistic features about the pattern of due-date variability, and results indicate that inventory performance is improved by order Rescheduling.
Abstract: This paper addresses the problem of open order rescheduling in a job shop. Results are reported of experiments conducted in a simulation model of an 8-machine job shop. Four different order updating policies are examined. The due-date process is modeled to include several realistic features about the pattern of due-date variability. These features are parameterized and tested at several levels. Tardiness results indicate that open order rescheduling is beneficial only when allowances are loosely set. The results indicate that inventory performance is improved by order rescheduling, particularly in cases when due dates are revised to earlier times than originally forecast.

Journal ArticleDOI
Bing Liu1
TL;DR: A detailed analysis of the scheduling process, within an AI framework, is proposed and it is suggested that the central problem is how to have a global perspective in the Scheduling process.

Journal ArticleDOI
TL;DR: In this article, the performance of selected dispatching rules in an unbalanced multistage job shop is evaluated to determine whether the performance is consistent for jobs which are routed through the bottleneck and for jobs that by-pass the bottleneck.
Abstract: In the multistage job shop, several parts are assembled to form sub-assemblies which are then assembled into final products. Job delays may occur due to the lack of capacity and also due to the lack of component parts necessary to form a subassembly. Previous research of similar systems have assumed a balanced capacity. A more realistic assumption is one in which machine capacities are not balanced such that one machine can be identified as a bottleneck. In this paper, the performance of selected dispatching rules in an unbalanced multistage job shop is evaluated to-determine whether the performance is consistent for jobs which are routed through the bottleneck and for jobs which by-pass the bottleneck.

Proceedings ArticleDOI
07 Dec 1988
TL;DR: In this paper, the authors present three extensions to the tactical planning model for a single-work-station setting, rather than for a network of work stations, to model unreliable work stations and incorporate variability due to lot sizing.
Abstract: The author outlines three extensions to the tactical planning model. For ease of presentation, the extensions are given for a single-work-station setting, rather than for a network of work stations. The extensions are (1) to model unreliable work stations; (2) to incorporate variability due to lot sizing, and (3) to include an explicit capacity constraint on production. >

Journal ArticleDOI
TL;DR: In this paper, the main and interaction effects of three shop decision variables: (a) the job dispatching rule, (b) the due-date assignment method, and (c) the shopload ratio, on a shop performance measure defined as the percentage of jobs late are investigated.
Abstract: This paper presents a study of a hypothetical job shop by computer simulation. The purpose is to investigate the main and interaction effects of three shop decision variables: (a) the job dispatching rule, (b) the due-date assignment method, and (c) the shopload ratio, on a shop performance measure defined as the percentage of jobs late. The multiple regression analysis technique is employed to estimate the functional relationship between the performance measure and shop decision variables. Two potential applications of the regression model are explored and discussed.

Dissertation
01 Jan 1988
TL;DR: In this paper, the authors developed an analytic and a simulation model for a job shop with unreliable work stations and production constraints, which is extended to the work station with production constraints and with given unreliability of its operation, because in real world situation, the work stations cannot be operated perfectly without any trouble nor infinite productivity.
Abstract: We develop an analytic and a simulation model for a job shop with unreliable work stations and production constraints. In the complex batch manufacturing operation of the factory, smooth production of each work station is required. In the previous work the Tactical Planning Model was proposed for this purpose. In that model, the production of each work station should be proportional to the queueing level of the input work flow. In this paper, the model is extended to the work station with production constraints and with given unreliability of its operation, because in the real world situation, the work stations cannot be operated perfectly without any trouble nor infinite productivity. For the analysis of multiple unreliable work stations, we develop an analytical model and solution. The break down of the work station is modeled as a Bernoulli process. For the analysis with the production constraints with or without the unreliable work station model, we develop a dynamic simulation model. We show some examples of this problem, and show the effect of production constraints and unreliable work stations. Thesis Supervisor: Dr. Stephen C. Graves Title: Professor of Management Science The contents of the thesis Chapter

Journal ArticleDOI
TL;DR: The authors have previously published details of an approach which sets the priority of a job as a linear combination of the operation times and due date for that job, which is then applied to data from an actual manufacturing system.
Abstract: The problem of sequencing jobs on a machine in a job shop has been approached by a number of researchers and practitioners. One of the most popular methods is to apply a priority rule to the queue at each machine. The authors have previously published details of an approach which sets the priority of a job as a linear combination of the operation times and due date for that job. The coefficients in the linear combination are set by a simulation and search procedure so as to give good performance based on the performance measure specified. This paper extends this approach to include setup time factors. This extended approach is then applied to data from an actual manufacturing system. The extended approach is shown to improve the performance of the manufacturing system in relation to existing techniques.

Journal ArticleDOI
TL;DR: A methodology for productivity improvement based on systems engineering principles is introduced in this paper, where the core of this approach is a systems model of job shop production, which also includes support functions affecting the productivity of the production process.

Proceedings ArticleDOI
23 May 1988
TL;DR: A real-time scheduling algorithm for a flexible manufacturing system environment that uses a schedule space search which is characterized by a heuristic-oriented approach based on simulation.
Abstract: A real-time scheduling algorithm for a flexible manufacturing system environment is described. This algorithm uses a schedule space search which is characterized by a heuristic-oriented approach based on simulation. The algorithm can be seen as a look-ahead dispatching rule, because the simulation-based search gives a forecast of how good a schedule can be, before choosing the best one. The algorithm structure is based on the fact that a minimal set of parts can be defined, which is a common divisor of the total number of parts. >

01 Jun 1988
TL;DR: In this paper, a simulation model is developed to test the operating effects of the type and number of pallets available to the flexible manufacturing system under low and high levels of demand variability.
Abstract: From a tactical point of view, Flexible Manufacturing Systems (fms) represent a way to obtain assembly line unit costs at job shop batch sizes. The strategic advantage of such technology is flexibility. The flexibility of such a system can be analyzed and defined into several components. This paper studies the flexibility associated with the type and number of pallets used to mount work in process in an fms. Increases in such flexibility are found to reduce costs by increasing the system's ability to take advantage of other existing types of flexibility inherent within an fms. A simulation model is developed based on an existing fms whose primary function is metal cutting. This model is used to test the operating effects of the type and number of pallets available to the fms under low and high levels of demand variability. A dedicated pallet is defined as capable of mounting only one given part. General purpose pallets are defined as being able to mount the entire part set. The analysis is two part. The first part of the analysis examines the results of the model under different levels of pallet flexibility, demand variability, and other parameters that are directly affected by the type and number of pallets in use. The second part of the analysis provides a framework for examining the economic implications of pallet flexibility. Example cases are discussed using the simulated performance results. The simulation results show that increased levels of pallet flexibility will decrease system makespan within the constraints imposed by other system resources. System makespan increases as the level of demand variability increases. The economic framework compares the cost of pallet flexibility against the value of increased system performance. The economic advantage gained with high levels of pallet flexibility can be offset by potential increases in pallet investment and/or the incremental scrap level associated with the use of general purpose pallets.

Journal ArticleDOI
TL;DR: In this paper, the authors discuss the project scheduling problems in the context of continuous production, mass production, batch production, job shop production, and project scheduling, where the typology of the production systems differs with the typologies of the jobshops.
Abstract: Historically, scheduling of production activities has been one of the most important management problems. Scheduling involves the planning and the co‐ordination of the various activities to achieve the optimum utilisation of resources over a given time period. Production scheduling differs with the typology of the production systems. Various production systems that are encountered in practice are: continuous production, mass production, batch production, job shop production and projects. In this article, we attempt only to discuss the project scheduling problems.

Book
01 Jan 1988
TL;DR: The suggested knowledge-based system approach to the development of real-time decision support system for shop floor scheduling has been shown to be feasible and to achieve better performance than that of other scheduling heuristic rules.
Abstract: This research addresses the stacker crane scheduling problem in a Computer Integrated Manufacturing (CIM) Environment. A single crane is used to move all the Work-In-Process (WIP) in the system. The overall system objective is to maximize the yield rate subject to the flow time limit of the WIP. We formalize the problem, and analytically and empirically show that cyclic scheduling provides a near optimal solution, which is superior to dispatching rules. First, we illustrate the optimality and benefits of cyclic scheduling in a simple environment. Then, for multiple product problems, we show that finding the minimum cycle time becomes the longest circular path problem in a graph. This can be solved in O($n\sp2$) steps, where n is the total number of products to be produced in a cycle. Based on the insights developed, a heuristic for sequencing product types in a cycle is derived that approximately minimizes the cycle time. The benefits of incorporating information from the cyclic schedule in the machine layout decision are also demonstrated. For a more complicated scheduling problem which include the machine failure issue, a knowledge-based system is developed for the real time control of the manufacturing environment. The knowledge-based system not only provides the current status of the manufacturing system and does the well-structured computational tasks, but also organizes the information and suggests a specific action. Unlike those simple heuristic rules that are used for most shop floor scheduling, this system schedules jobs in cyclic approach and when machines break down it selects an appropriate action to take based on the current status of the manufacturing system. Different rules are used to control the system under different conditions. Similar to other knowledge-based systems, it can be modified by simply adding, subtracting or changing rules in the knowledge base without affecting the other modules of the system. The suggested knowledge-based system approach to the development of real-time decision support system for shop floor scheduling has been shown to be feasible. Given a specific job shop, we also show that a knowledge-based system developed for this system achieve better performance than that of other scheduling heuristic rules. The advantages and disadvantages of this approach are also discussed.

Journal ArticleDOI
T. Lee1
TL;DR: In this article, an integrated scheduler (INSCH) is developed for small job shop manufacturing systems while considering high machine utilization, low work-in-process, and reduced job lateness.

DOI
01 Jan 1988
TL;DR: In this paper, the authors propose a method to solve the problem of the problem: this paper.x.x.q.x.q.q.,q.e.
Abstract: x

Book ChapterDOI
01 Jan 1988
TL;DR: This paper describes a computer oriented combinatorial algorithm for establishing optimal machine loading in any job shop engaged in metal cutting industry.
Abstract: This paper describes a computer oriented combinatorial algorithm for establishing optimal machine loading in any job shop engaged in metal cutting industry. A few of the recent research papers had attempted to analyze constrained problems like scheduling n jobs on single machine [1] or use of computer simulation to solve actual job shop problems using group technology [2]. However in most of the models the simplicity is lost due to complex mathematical expressions or long computer programs.


Book ChapterDOI
01 Oct 1988
TL;DR: Batch manufacture occurs where the demand for individual items is insufficient to justify the installation of dedicated resources and other mass manufacturing techniques for the production of each item.
Abstract: Batch manufacture occurs where the demand for individual items is insufficient to justify the installation of dedicated resources and other mass manufacturing techniques for the production of each item. The batch manufacturing environment, or job shop, consists of general-purpose machine tools capable of being fitted with various tools and fixtures to perform a wide variety of jobs. Individual items are grouped in batches, and their production proceeds in a series of discontinuous steps.