Showing papers on "Flow shop scheduling published in 1980"
434 citations
TL;DR: In this article, the basic features of flexible manufacturing systems are reviewed and models for determining the production capacity of such systems are developed, showing the desirability of a balanced work load, the benefit of diversity in job routing if there is adequate control of the release of jobs, and the superiority of common storage for the system over local storage at machines.
Abstract: The basic features of flexible manufacturing systems are reviewed and models for determining the production capacity of such systems are developed. These models show the desirability of a balanced work load, the benefit of diversity in job routing if there is adequate control of the release of jobs (a job shop can be better than a flow shop), and the superiority of common storage for the system over local storage at machines. The models are extended to allow for material handling delays between machines and for unreliable machines. It is also shown that production capacity models can be used to develop good approximations to the mean number of jobs in the system for given job arrival rates and machine utilizations.
278 citations
TL;DR: New heuristic scheduling rules are determined which give high performance for flow-shop scheduling where there is (i) no job-passing and (ii) noJob-waiting.
Abstract: Existing methods are reviewed and new heuristics examined and developed for the flow-shop scheduling problem. Comparative tests are carried out using simulation methods on different sizes of problem and with different variability of processing time data. New heuristic scheduling rules are determined which give high performance for flow-shop scheduling where there is (i) no job-passing and (ii) no job-waiting.
189 citations
TL;DR: In this article, a branch-and-bound algorithm is presented for the permutation flow-shop problem, in which the objective is to minimize the maximum completion time, and a branching procedure is used in which jobs both at the beginning and at the end of the schedule have been fixed.
85 citations
TL;DR: This paper deals with the problem of minimizing the weighted mean flow-time in n/m flow-shop scheduling where no passing is allowed and an algorithm based on inequalities is proposed to obtain the optimal or near optimal solution.
Abstract: ANALYSIS FOR MINIMIZING WEIGHTED MEAN FLOW-TIME IN FLOW-SHOP SCHEDULING Shigeji Miyazaki and Noriyuki Nishiyama University of Osaka Prefecture (Received May 11, 1979; Revised February 7, 1980) This paper deals with the problem of minimizing the weighted mean flow-time in n/m flow-shop scheduling where no passing is allowed. Analysis, through the adjacent pairwise interchange method, leads to a condition for determining the precedence relation between adjacent jobs. The condition consists of inequalities, the number of which equals the square of the number of machines. An algorithm based on these inequalities is proposed to obtain the optimal or near optimal solution. The numerical examples show that the algorighm can produce a solution which has an average approximation ratio of 91.4 percent over 160 problems. The three factors: the number of jobs, the number of machines and the range of weights do not affect the approximation ratio of the tested problems. The computational time required to obtain a solution through the proposed algorithm is proportional to (the number of jobs) x (the number of machines)2. As a result, the CPU time needed to solve a seven job and six machine problem through TOSBAC 5600/120 is 0.25 sec.
44 citations
TL;DR: Ease of implementation of the various procedures in a real world job shop environment is discussed, and a simple modification to remove the anomaly in ratio type dynamic priority rules is suggested.
Abstract: Dynamic priority dispatching rules in job shops require the computation of all job priorities in a work center queue every time a machine in the work center becomes idle. This is extremely costly. Alternative priority update procedures are studied and comparative results in terms of performance measures and costs are reported. Ease of implementation of the various procedures in a real world job shop environment is discussed. A second problem related to an anomaly in ratio type dynamic priority rules is also studied; a simple modification to remove the anomaly is suggested and the performances of the "old" and "modified" procedures are compared.
40 citations
TL;DR: The ordered flow shop sequencing problem with no in-processing waiting (OFSNW) is considered and it is shown that the sequence in which jobs are arranged according to the shortest processing time rule (SPT) represents an optimal sequence.
Abstract: The ordered flow shop sequencing problem with no in-processing waiting (OFSNW) is considered with respect to mean flow time criterion. It is shown that the sequence in which jobs are arranged according to the shortest processing time rule (SPT) represents an optimal sequence. Additional results for the makespan criterion are also discussed.
28 citations
TL;DR: In this article, a large petrochemical plant is modeled as a job shop where the orders are of two types, emergency and non-emergency, and the emergency orders can be delayed until later.
Abstract: A maintenance planning and scheduling system often resembles that of a ‘job shop’ that is, the orders are one of a kind, and is characterized by having to schedule N orders through M or less tasks. The orders are of two types, e.g., (a) emergency—have to be done now, and (b ) non-emergency—can be delayed until later. In this type of ‘job shop’ the schedule becomes immediately out of date as soon as an emergency order is received. Consequently non-emergency orders are continually moved back in the schedule and forecasted completion dates are not met. Further if the orders entering the system exceed the normal available capacity, the backlog will continue to increase causing more disruption of schedules. The research, which is based on a large petrochemical plant, will deal with the above problems by (a) applying dynamic decision rules for day-to-day scheduling to ensure completion dates are met, (b) a method for controlling backlog, and (c) forecasting future load, and completion dates for orders. The resu...
20 citations
19 citations
TL;DR: In this paper, the problem of finding a minimum makespan permutation schedule in a deterministic flow-shop without intermediate queues is equivalent to the shortest distance routing traveling salesman problem, and an algorithm, having quadratic worstcase complexity in terms of the number of partial schedules explicitly enumerated, has been presented.
Abstract: The problem of finding a minimum makespan permutation schedule in a deterministic flow-shop without intermediate queues is equivalent to the shortest distance routing traveling salesman problem. If the task system is semi-ordered, the associated distance matrix of the corresponding traveling salesman problem is found to exhibit some peculiar characteristics. Consequently, we are able to derive some important results which help us to eliminate permutations in the search of the minimum makespan permutation schedule. The most important result is that the optimal permutation schedule is pyramidal. An algorithm, having quadratic worst-case complexity in terms of the number of partial schedules explicitly enumerated, has been presented. Some particular cases of the semi-ordered flow-shop are also discussed.
18 citations
TL;DR: Scheduling is defined by Baker as, “the allocation of resources over time to perform a collection of tasks”, which may involve a variety of different operations.
Abstract: Scheduling is defined by Baker as, “the allocation of resources over time to perform a collection of tasks”. The term facilities is often used instead of resources and the tasks to be performed may involve a variety of different operations.
TL;DR: A variety of modifications to this basic theme of scheduling tasks on a system consisting of two parallel processors in order that makespan be minimized are treated, including the cases of identical, proportional, and unrelated processors.
Abstract: This paper is concerned with the problem of scheduling tasks on a system consisting of two parallel processors in order that makespan be minimized. In particular, we treat a variety of modifications to this basic theme, including the cases of identical, proportional, and unrelated processors. In addition, a heuristic scheme is suggested when precedence constraints exist where such constraints may be assignment dependent. Substantial computational experience is reported in all cases where it would appear that relatively large problems can be handled routinely.
TL;DR: In this paper, a new method for solving perturbation problems in the course of production scheduling of cutting operations in the field of machine tool manufacture is presented, which can adapt machining times to actual production situations and therefore meet due dates without a need for overtime operation.
TL;DR: In this article, the Weibull distribution is used as the limiting form of the frequency distribution of the smallest members of samples of feasible job-shop schedules, and estimates of the optimal solution are obtained by calculating the most likely value of the weibull location parameter, allowing a tight bracket for the optimal makespan value.
Abstract: The paper examines how the computational efficiency of tree search applied to job-shop scheduling problems may be improved by a statistical method which provides both a bound and stopping rule for the search process. The Weibull distribution is used as the limiting form of the frequency distribution of the smallest members of samples of feasible job-shop schedules. Estimates of the optimal solution are obtained by calculating the most likely value of the Weibull location parameter, allowing a tight bracket for the optimal makespan value to be established. Estimates of the optimal solution of sub-problems with fixed partial sequence are proposed as approximate lower bounds for a ‘best-bound’ search strategy.
TL;DR: It was found that interactive scheduling usually gave better results than the automatic method used alone but not at all times, and job stream conditions are identified where the interactive scheduling method was superior, where it was equivalent to, or inferior to the fully automatic methods used.
TL;DR: In this article, the authors present a new approach for the maximization of productivity taking into account the daily fluctuations in the work force, which is based on an average estimate of capacity and on the state of the plant.
Abstract: In this paper we discuss a fairly typical production scheduling problem. After some considerations on the structure of the process, a new approach is presented. The scheduling system proposed aims at the maximization of productivity taking into account the daily fluctuations in the work force. Encouraging results are reported. A Real Case When the plant manager took us around for a tour of the production facilities, we saw inventories piled up everywhere. "It seems that there is no way," the manager stated, "to get a smooth assembling of these damn machines. Often we have very small lots that require a smooth production flow, but when people do not show up at work in the morning we are forced to make too many changes to the production schedule. Everything gets screwed up and productivity goes down." The plant is located in Italy and is devoted to the production of large home appliances; it belongs to one of the biggest European groups in the industry. The aggregate production plan, which covers a time span of one month, is sent from the corporate headquarters thirty days in advance. This plan is based on an average estimate of capacity, essentially depending on the work force available and on the state of the plant, provided by the plant management itself two months before. The production supervisor of the plant is then responsible for disaggregating the plan into a schedule which specifies day by day for two weeks what must be produced and how
TL;DR: Once the classifier described herein has been determined, the pattern recognition approach may be exploited to overcome the dimensionality and computational requirements in such a massive dynamic scheduling problem.