Showing papers on "Flow shop scheduling published in 1969"

Multiproject Scheduling with Limited Resources: A Zero-One Programming Approach

Abstract: A zero-one 0-1 linear programming formulation of multiproject and job-shop scheduling problems is presented that is more general and computationally tractable than other known formulations. It can accommodate a wide range of real-world situations including multiple resource constraints, due dates, job splitting, resource, substitutability, and concurrency and nonconcurrency of job performance requirements. Three possible objective functions are discussed; minimizing total throughput time for all projects: minimizing the time by which all projects are completed i.e., minimizing makespan; and minimizing total lateness or lateness penalty for all projects.

Optimal Preemptive Scheduling on Two-Processor Systems

Abstract: One of the important potentials of multiprocessor systems is the ability to speed the completion of a computation by concurrently processing independent portions of the job. In this paper we consider the static scheduling of computations for a system containing two indentical processors. The object is to complete the computation in the minimum amount of time. A computation is assumed to be specified as a partially ordered set of tasks and the execution time for each task. A solution for the two-machine case with preemptive scheduling is presented.

The Influence of Setup Time on Job Shop Performance

Abstract: A job shop was simulated in order to determine the effect of different job priority rules involving setup times on shop performance. The seven priority rules tested were chosen on the basis that they could be implemented by job shop foremen. Assumptions in the simulation model were based on experience with an electronics company and published literature. The study indicates that, for a fully loaded shop, giving priority to be the job with the shortest actual setup time, regardless of its run time, gives the best overall performance result.

A Computer Aided Decision System

Abstract: The use of on-line, real-time computer-based information systems to augment managerial decision making raises interesting and significant questions. In search of operational answers, the authors have developed and conducted experiments with a time-sharing computer model. By modeling the dynamics of a job shop the authors were able both to make use of and to evaluate academic research in job shop scheduling. The authors have devised a specific apportionment of the problem environment which permits users of their information system to explore the effects of various combinations of heuristics and programmed decision rules. The response of over 300 managers and academicians who have participated in the experiments provides evidence of the practicality of such an approach to multi-dimensional, time-variant problem solving.

The Sequencing Problem

Abstract: This paper surveys methods proposed in the literature for determining the optimal solution to “N Job, M Machines” scheduling problems when there are no due dates or priorities and the sole objective is to complete all operations in least time.

Job shop scheduling by means of simulation and an optimum-seeking search

Abstract: The paper discusses a job shop simulator designed for use in the scheduling of a set of jobs. The simulator has been implemented in the form of a Fortran program. The simulator can be used in conjunction with a search program that adjusts priority rule parameters in seeking an improved schedule.

Job Shop Scheduling with Regular Batch Arrivals

Abstract: This paper describes a simulation exercise of a hypothetical machine shop consisting of five non-identical machines. Jobs arrive in batches, each job having its own routing and operation time specifications, the average times being normally distributed. Nine alternative loading rules are investigated and the SI rule (the selection of the job with the shortest imminent operation) is found to be the most effective in reducing the mean job throughput time and delay factor, when the batch size is comparatively small. For large batches, however, the results suggest that the SI rule is not the most effective. Ways to reduce the variance of job waiting times are also investigated.

A heuristic approach to algorithms intended for the solution of the timetable-problem

Abstract: Part I outlines the principles of the collision strategy also useful for the solution of very general job-shop scheduling problems. Part II gives a general flow-chart of the used program Part III discusses the construction of critical matrices. Within those matrices the collision algorithm is tested. The discussed strategies allow solutions with a probability of about 10−75. Improved strategies were sucessful applied to test examples with probabilities smaller than 10−400. Par IV presents an outlock on further improvements.

A Machine Release Scheme for the Job Shop Work Center

Abstract: The job shop may be viewed as a network of queues with each work center then defined as a single or multichannel service facility. In the low volume situation, manufacturing improvements may be expected of each work station. The effect of learning at the service facility will be seen as a reduction of queue congestion and a lessening of unit waiting time. This may eventually lead to excessive idle service capacity or reduced machine utilization. Where there are several machines at each work station, and learning can be expected, a scheme can be developed wherein machines could be released on a schedule to other work assignments while maintaining a relatively constant level of machine utilization.

Simulating scheduling plans

Abstract: This model simulates the activities of planning and manufacturing batches of components in a job shop. Simulation of the planning stage forms the basis of a tool to completely reschedule the shop from its actual position, having regard to due dates and machine resources. The execution of this plan is simulated giving management data on the effects of present decisions. A significant feature of the model is the use of simulation of present clerical rules as a basis for a more powerful shoploading system.