Showing papers on "Flow shop scheduling published in 1975"

A Comparative Study of Flow-Shop Algorithms

Abstract: This paper describes an experimental comparison of flow-shop algorithms, motivated by the need to consolidate recent research on this topic. Using a set of test problems, it investigated various branch-and-bound and elimination strategies in a comparative study and then combined them to produce a new and efficient solution algorithm.

Search and Simulation Selection of a Job-Shop Sequencing Rule

Abstract: A standardized approach to selecting a simple sequencing rule for decentralized application throughout a job shop is developed and illustrated. The sequencing rule is a linear combination of decision factors, each of which is initially assigned a relative weighting. The rule is then used to determine the priority of each job in the queues, and resulting shop costs are determined by computer simulation. The coefficients of the priority function are thereafter modified by a patterned search procedure to find priority coefficients that minimize expected cost per order for a specified cost structure. The cost structure is a combination of multiple response measures for the shop. Rather than leading to a “single best rule” for all job shops, the approach is a “method for finding” a sequencing rule that performs well in any specific job shop situation.

Critical Ratio Scheduling: An Experimental Analysis

Abstract: Critical Ratio scheduling has been implemented in job shops that manufacture component parts for stock replenishment as well as direct customer orders. Proponents of this technique argue that scheduling performance is improved by gathering and processing two different types of operating information on a routine basis for use in making priority scheduling decisions: queue waiting time information for individual machines and stock status information from the shop's inventory system. Simulation experiments are reported here which describe the effect on the performance of a shop and its associated inventor' system when using this type of information with an Order Point inventory control system. The results indicate that the additional information provided by the increased data collection and processing functions does not contribute a statistically significant improvement in the overall performance of the production system.

Exact, Approximate, and Guaranteed Accuracy Algorithms for the Flow-Shop Problem n / 2 / F / F¯

Abstract: Improved exact and approximate algorithms for the n-job two-machine mean finishing time flow-shop problem, n/2JF/P, are presented While other researchers have used a variety of approximate methods to generate suboptimal solutions and branch-and-bound algorithms to gen- erate exact solutmns to sequencing problems, thin work demonstrates the computatmnal effectiveness of couphng the two methods to generate solutmns with a guaranteed accuracy. The computational reqmrements of exact, approximate, and guaranteed accuracy algorithms are compared expem- mentally on a set of test problems ranging in size from 10 to 50 jobs The approach is readily apphca- ble to other sequencing problems

Coordinating Aggregate and Detailed Scheduling in the One-Machine Job Shop: II—Computation and Structure

Abstract: A previous research report of the authors presented a formal model of the one-machine job-shop scheduling problem with variable labor capacity. This report presents some computational experience with the algorithm proposed previously and a discussion of the structural aspects of the problem. Extensions and refinements of the algorithm are introduced to deal with nonsimultaneous job arrivals and the production smoothing problem. These results provide insight into the structure of the aggregate-detailed cost trade-off problem and suggest a good heuristic decision rule for problems of realistic size and complexity.

Experiments with the SIX rule in job-shop scheduling:

Abstract: This paper reports on the results of various experi ments with the loading rule SIx for scheduling jobs and compares its performance with two other, general ly more popular, methods. Several advantages of the SIx rule are discussed.

Balancing Workloads and Minimizing Set-up Costs in the Parallel Processing Shop

Abstract: This paper presents an optimal scheduling algorithm for minimizing set-up costs in the parallel processing shop while meeting workload balancing restrictions.

An Algorithm for a Single Machine Scheduling Problem with Sequence Dependent Setup Times and Scheduling Windows

Abstract: An enumeration algorithm is presented for solving a scheduling problem similar to the single machine job shop problem with sequence dependent setup times. The scheduling problem differs from the job shop problem in two ways. First, its objective is to select an optimum subset of the available tasks to be performed during a fixed period of time. Secondly, each task scheduled is constrained to occur within its particular scheduling window. The algorithm is currently being used to develop typical observational timelines for a telescope that will be operated in earth orbit. Computational times associated with timeline development are presented.

Job Shop Scheduling with Due Dates and Operation Overlap Feasibility

Abstract: The job shop problem with due dates is formulated to allow overlaps among successive operations on a job. Multiple transports of sub lots and existence of setup times are two applications where this formulation can result in technologically feasible schedules. A procedure is described for generating overlap schedules and it is applied to eight test problems from the literature. The resulting schedules are compared to alternative schedules involving tardiness or overtime. The results indicate that the procedure is effective in generating multiple transport schedules for the manager's consideration. The comparative data provide useful tradeoff information for evaluation of alternatives and indicate that multiple transport scheduling may sometimes be a very economical way to try to meet due dates without using overtime operations.

Scheduling a Single Machine System: A Multi-product Multi-item Case

Abstract: A scheduling problem having the characteristics: is reported in this paper. A systematic procedure is presented for tackling such scheduling problems. An example has been solved to illustrate the method.

An improved branch and bound procedure for n × m flow shop problems

Abstract: This paper considers the classical nXm flow shop sequencing problem. An improved branch and bound procedure is proposed. Computational experience shows that the proposed procedure is more efficient compared to the existing optimizing procedures.

An implicit enumeration algorithm for complex scheduling problems

Abstract: Several algorithms have been presented for handling complex scheduling problems. These methods are computationally impractical when confronted with large problems. New algorithms have been developed for solving job-shop problems. They are more efficient than the previous ones because they use dominance and better bound ideas. The purpose of this paper is to present an efficient algorithm for complex scheduling problems generalizing those ideas.

Technical Note—An Elimination Method for the Flow-Shop Problem

Abstract: Elimination methods for the flow-shop problem have been investigated by-several authors using special elimination conditions to construct a set of dominant schedules and then enumerate them in order to find an optimum. The few papers reporting computational experience with elimination algorithms indicate that the approach may be an efficient method for obtaining optimal schedules. This note builds a simple model in order to help provide some perspective on these computational results and to describe how elimination algorithms may behave in moderate-sized problems.

Rules for scheduling semi-automatic machines with deterministic cycle time

Abstract: A considerable amount of research has been conducted into the use of decision rules for scheduling in the job-shop environment. The research discussed in this paper is of a similar nature but concerned with the use of rules for controlling the service operation to semi-automatic machines where, the. run times and service times are, in the main, deterministic. The set of rules studied is different to those of the job-shop scheduling problem since the. products are manufactured, under batch conditions. Producing for stock means that delivering dates are not important but the idle time of machines is very important. The behaviour of a set of ten rules is studied and their performance measured by four different, but reasonable, criteria. The results of the study indicate that under most conditions and measured by several, but not all, of the criteria used, the rule serve the machine, awaiting service with shortest required service time, performs best. That is the conclusion is similar to the job-shop studies ...

Algorithms for scheduling projects with limited resources

Abstract: During recent years decision procedures for scheduling projects with limited resources have become more complex. It is therefore, desirable to allow for more aspects of the real world when developing such procedures. The present paper begins with a brief survey of the manner in which the above scheduling problem has heretofore been defined and solved. Next, this problem is reformulated in order to allow for the treatment of predicted streams of costs and benefits of a project, as a function of calendar time. The method developed in this paper consists of two algorithms. Application of the first algorithm results in a good initial solution to the scheduling problem and is, therefore, a heuristic procedure. Next, a second algorithm which guarantees an optimal solution is applied to this initial solution. Computational experience with the aforementioned two algorithms indicates that their combined application is an efficient method for scheduling projects with limited resources.

Job shop scheduling in an electroplating environment

Abstract: As operating costs continue to escalate, management must become more aware of the importance of increased productivity through increased efficiency. Scheduling by priority loading rules is one way of contributing towards the improved operation of the job shop. A computer simulation was used to study the performance variations of scheduling with eight different priority loading rules, of a job shop in an electroplating environment. The processing set-up of the shop was unique in that various plated finishes were obtained on various base-metals from a single system in which the processing tanks were physically arranged in a single line in series, and each base-metal-finish combination followed a specific pre-determined processing route. The plating job shop environment described, is shown in simplified flow chart form in Figure 1. The work to be processed was placed on racks and subsequently on to a movable bar before being transferred between the various processing tanks using automatically programmed travelling hoists. For our purposes, this system can process any one of the following base metal-finish combinations: Base metal finish (i) Zinc-brass (ii) Zinc-chrome (iii) Steel-brass (iv) Steel-chrome

Computational Experience with a Cost-based Algorithm for the Shop Scheduling Problem

Abstract: This paper reports on the formulation and testing of an economically structured algorithm for the static shop scheduling problem. A lower bound on machine idle and job penalty cost as well as a rescheduling feature which treats job-waiting cost was developed.

On Ashour's decomposition algorithm for shop scheduling problems

Abstract: This note exposes an oversight in the development of a decomposition approach to the shop scheduling problem reported previously. Included is a brief account of the original algorithm, exposure of its weakness via a small example and a suggested modification.

Some Insights Into Deterministic Scheduling Problems Involving Multiple Resources and Preemption

Abstract: This paper considers deterministic scheduling problems for systems having a nUmber of different resource types and an arbJtrary number of units of each resource. General results are obtained for preemptiveresume scheduling rules under the condition of zero preemption costs. Schedule completion time 15 the objective function considered, and the paper examines the relative effect of demand scheduling and precedence constraints on the minimum schedule completion time.

Computer network scheduling

Abstract: This paper presents a method for solving the scheduling problem of a computer-network. There are three possible criteria for optimality: (1) Maximum number of jobs to be processed per given period. (2) Minimum idle time for each of the computers in the network, or in other words, maximum utilization. (3) Optimizing an objective function which combines 1 and 2 and which may consider additional factors.