Showing papers on "Job shop published in 1985"
TL;DR: A family of algorithms is described for finding optimum schedules for job-shops that are of a branch and bound type but have a complete schedule associated with each node of the search tree.
Abstract: A family of algorithms is described for finding optimum schedules for job-shops. The algorithms are of a branch and bound type but have a complete schedule associated with each node of the search tree. Branching from nodes is based on important conflicts in the schedule. Some results are provided.
82 citations
TL;DR: In this article, the effects of various labor assignment rules on the shop's performance were examined in a dual-constrained job shop and the results showed that none of the eleven rules had a significant impact on shop performance.
74 citations
TL;DR: 11 sequencing rules (some of which are common to simple job shops and some decigned specifically for assembly shops) are evaluated using a simulation analysis of a hypothetical assembly shop using an ANOVA procedure.
Abstract: Research relating to sequencing rules in simple job shops has proliferated, but there has not been a corresponding proliferation of research evaluating similar sequencing rules in more complex assembly job shops. In a simple job shop, all operations are performed serially; but an assembly shop encompasses both serial and parallel operations. As a result of the increased complexity of assembly shops, the results associated with the performance of sequencing rules in simple job shops cannot be expected for an assembly shop. In this paper, 11 sequencing rules (some of which are common to simple job shops and some decigned specifically for assembly shops) are evaluated using a simulation analysis of a hypothetical assembly shop. The simulation results are analyzed using an ANOVA procedure that identifies significant differences in the results of several performance measures. Sensitivity analysis also is performed to determine the effect of job structure on the performance of the sequencing rules.
56 citations
TL;DR: This paper investigates the job-shop due-date assignment problem with a customer ‘service-level’ constraint, the percentage of time that promised delivery dates are honoured, and forms a rule to attain this service level, yet maintain as short a due- date lead time as possible.
Abstract: The job-shop due-date assignment problem arises when a manager needs to ‘promise’ a delivery date to a customer. Previous methods yield due-dates which are either optimistic (unlikely to be achieved) or conservative (the promise will be met, but too easily, because the date given was very pessimistic). This paper investigates the due-date assignment problem with a customer ‘service-level’ constraint, the percentage of time that promised delivery dates are honoured. We formulate a rule to attain this service level, yet maintain as short a due-date lead time as possible. Unlike previous attempts, this due-date rule considers not only the job content and instantaneous shop congestion information, but also implicitly incorporates information on how the jobs will be scheduled (or ‘loaded’) once they are in the shop. We simulate a single-machine shop for various measures of performance under several dispatching priorities, comparing our due-date rule with one reported to yield satisfactory performance. Our rule meets all requirements and is found to be superior for most measures of performance.
53 citations
TL;DR: This paper studies the impact of job routing pattern on the performance of dual resource constrained (DRC) systems and concludes that routing pattern has no significant impact on the relative effectiveness of various dispatching rules.
Abstract: This paper studies the impact of job routing pattern on the performance of dual resource constrained (DRC) systems. Three markedly different job routing patterns are simulated using a DRC system model that incorporates labor transfer times. The problem is viewed from two perspectives: one portion of the analysis focuses on the relative performances of five different dispatching rules as the routing pattern varies; the other examines the effect of the routing pattern on each rule's individual performance. One generalized conclusion of this study is that routing pattern has no significant impact on the relative effectiveness of various dispatching rules. Consequently, findings from pure job-shop research studies may be applied to situations where a mixture of job-shop and flow-shop routings is present.
37 citations
TL;DR: In this paper, an approach to the job shop sequencing problem by determining the priority of a job from a linear combination of the basic quantities of operation times and due dates is presented.
Abstract: This paper sets out, an approach to the job shop sequencing problem by determining the priority of a job from a linear combination of the basic quantities of operation times and due date. This achieves a simple yet unified format. Furthermore, since these basic quantities are used in fixed linear combinations in the majority of well-known simple heuristics, the rule outlined in the paper is capable of representing such heuristics as special cases within its framework. A performance function is used to assess the effectiveness of the rule and no limitations are imposed on its structure. The form of the variable priority rule is then determined by a computer search routine basing its decisions on the values of the performance function. This overall approach to job shop sequencing we term the search sequencing rule (SSR).
34 citations
TL;DR: In this paper, the authors discuss the economics of job shop production under Poisson order-arrival and present an operational basis for job shop control, which consists of job orders with marginal profits, selection function with backlog, and a production centre with fixed capacity.
Abstract: Under Poisson order-arrival, this paper discusses the economics of job-shop production by a policy approach, and presents an operational basis for job shop control. The model consists of job orders with marginal profits, selection function with backlog, and a production centre with fixed capacity. For the two main policies, PSP and DSP, this model is formulated by semi-Markov decision processes, and the operation rate, mean shop-time and reward rate (including idle cost) are obtained. Finally, the relationship of ‘six order-selection policies is given, and the structure of optimal policies is suggested.
20 citations
01 Jan 1985
TL;DR: In this paper, the authors propose a skill-based production approach for small batch production. But, they focus on the use of computers on the shop floor and in the technical office in an integrated manner.
Abstract: Past development of small batch production has led to advanced horizontal and vertical division of labor, job shop manufacturing, and the use of NC machines. This caused serious difficulties such as long and variant throughput times, an unfavorable ratio of unproductive to productive workers, and low quality of work. Additionally confronted with deeply changed market conditions, management is split in two lines struggling for the right answer to this challenge. Most managers and production planners try to replace human work still further by enforced use of computers on the shop floor and in the technical office in an integrated manner (CIM). Since this strategy is in danger to create new severe problems, the minority seeks to avoid them by reorganizing production and rearranging the division of functions between man and machine profoundly (skill based production). This position is outlined in some detail including examples of realized subsystems as first steps on this development path.
20 citations
TL;DR: In a flow shop where the machine speeds increase from the first to last machine and the workload distributions are ordered by a likelihood ratio criterion, then the makespan of the jobs is stochastically minimized by processing the jobs in the order of least to greatest (greatest to least) workload.
Abstract: We consider stochastic models for flow shops, job shops and open shops in which the work required by job j is the same at each machine, being a random variable Wj. Because machines operate at different speeds, Si, the processing time of job j at machine i is Wj/Si,. It is the main result of this note that in a flow shop where the machine speeds increase (decrease) from the first to last machine and the workload distributions are ordered by a likelihood ratio criterion, then the makespan of the jobs is stochastically minimized by processing the jobs in the order of least to greatest (greatest to least) workload.
19 citations
TL;DR: In this article, a manufacturing cell control system (MCCS) is proposed for a small (4 to 6 machines) job shop production flexible manufacturing cell, which aims to solve the technological and scheduling problems of manufacturing in systems having a scarcely predictable and turbulent mix of products.
18 citations
TL;DR: In this article, the effectiveness of composite time/cost priority-scheduling rules on both time and cost performance measures is explored, at various shop-utilization levels, against standard and modified time-based rules such as critical ratio and shortest processing time.
Abstract: This paper explores the effectiveness of composite time/cost priority-scheduling rules on both time and cost performance measures. These dispatching rules, based on value added or profitability, are compared, at various shop-utilization levels, against standard and modified time-based rules such as critical ratio and shortest processing time. The simulation of a randomly routed job shop shows that work in process can be significantly reduced with varying sacrifices in time-performance measures. At moderate levels of utilization, the results suggest that these dollar-based rules perform quite well. Both tabular and graphic, results are shown to clarify the tradeoffs which result.
TL;DR: It is shown that the analytical model used for determination of the mean and standard deviation of the job flow-time in a job shop in which the F.F.C.S. dispatching rule is in use is quite robust at a low level of shop load.
Abstract: This paper is concerned with analytical determination of the mean and standard deviation of the job flow-time in a job shop in which the F.C.F.S. dispatching rule is in use. A hypothetical job shop is constructed to generate simulation results for comparison with the analytical results. Consistency of the results reveals the validity of the analytical model. It is also shown that the model is quite robust at a low level of shop load. So the model can be applied to analyze certain types of actual shops.
TL;DR: A zero-one integer programming model for the job shop scheduling problem with minimum makespan criterion is presented in this article, which consists of two parts: (a) a branch and bound parametric linear programming code for solving the problem with fixed completion time; (b) a problem expanding algorithm for finding the optimal completion time.
Abstract: A new zero-one integer programming model for the job shop scheduling problem with minimum makespan criterion is presented. The algorithm consists of two parts: (a) a branch and bound parametric linear programming code for solving the job shop problem with fixed completion time; (b) a problem expanding algorithm for finding the optimal completion time. Computational experience for problems having up to thirty-six operations is presented. The largest problem solved was limited by memory space, not computation time. Efforts are under way to improve the efficiency of the algorithm and to reduce its memory requirements.
TL;DR: In this paper, the operating characteristics of the total-work-content (TWK) due-date assignment method in a dynamic job shop were studied and an analytical procedure was presented to derive the optimal solution and to show that k ∗ p is a unique absolute minimum point of the strictly convex cost functions included in the cost model.
Abstract: The paper studies the operating characteristics of the total-work-content (TWK) due-date assignment method in a dynamic job shop. The due-date for each job is established by adding a multiple of the job's total processing-time to its arrival time at the shop. It is assumed that there will be penalty costs if the shop quotes excessively long due-dates compared with its competitors' and cannot complete the jobs exactly on their assigned due-dates. A cost model composed of these two opportunity cost components is used. The objective is to find the optimal processing-time multiple k ∗ p that will minimize the expected total cost per job. An analytical procedure is presented to derive the optimal solution and to show that k ∗ p is a unique absolute minimum point of the strictly convex cost functions included in the cost model. It is also shown that determination of the optimal processing-time multiple requires only information readily accessible in the shop. Under certain circumstances, k ∗ p can even be exclu...
TL;DR: Three simulation languages are quantitatively compared in a manufacturing job shop environment to obtain data on compilation time, execution time, CPU time, memory time and the rate of change of these variables due to changes in the simulation period.
TL;DR: Models are described that facilitate the use of an electronic spreadsheet for analyzing the flow of work in process through manufacturing system and it is shown that the spreadsheet-modeled analytic approach works best for the flow shop configuration.
01 Jan 1985
TL;DR: Flexible Manufacturing Systems deal with high-level distributed data processing and automated material flow using computer-controlled machine tools, robots, co-ordinate measuring machines, etc., with the aim of combining the benefits of a highly productive, but inflexible transfer line and a highly flexible, but inefficient job shop.
Abstract: Flexible Manufacturing Systems deal with high-level distributed data processing and automated material flow using computer-controlled machine tools, robots, co-ordinate measuring machines (CMM> , assembly robots and automated material handling and storage devices, etc., with the aim of combining the benefits of a highly productive, but inflexible transfer line and a highly flex ible, but inefficient job shop.
TL;DR: In this paper, the authors considered the role of labour flexibility in improving the performance of a real-life job shop and modelled the real life system with the aid of a digital simulation model.
TL;DR: In this paper, the authors argue that the past development of small batch production has led to advanced horizontal and vertical division of labor, job shop manufacturing, and the use of NC machines, which caused serious difficulties such as long and variant throughput times, an unfavourable ratio of unproductive to productive workers, and low quality of work.
TL;DR: In this paper, the authors examine the problems of management and control of large scale multi-product multi-line batch manufacturing outside the mechanical engineering industries and describe a number of decision support tools which could be used at different levels of the production hierarchy.