Showing papers on "Flow shop scheduling published in 1982"

Recent Developments in Deterministic Sequencing and Scheduling: A Survey

Abstract: The theory of deterministic sequencing and scheduling has expanded rapidly during the past years. We survey the state of the art with respect to optimization and approximation algorithms and interpret these in terms of computational complexity theory. Special cases considered are single machine scheduling, identical, uniform and unrelated parallel machine scheduling, and open shop, flow shop and job shop scheduling. This paper is a revised version of the survey by Graham et al. (Ann. Discrete Math. 5(1979) 287–326) , with emphasis on recent developments.

Minimizing the Expected Makespan in Stochastic Flow Shops

Abstract: The optimization problem of minimizing the completion time in permutation flow shop scheduling is considered under the assumption that the processing times of a job on different machines are independent and identically distributed random variables. Models with and without intermediate storage are considered. Solutions for special cases are found and based on these results a more general rule of thumb is obtained.

Job shop scheduling heuristics and frequency of scheduling

Abstract: This paper presents a job scheduling problem. Two important aspects are included in the subsequent analysis. The first is the dynamic nature whereby new jobs arrive to be included intermittently through time. The second is the uncertainty, or error in estimating process times, and the likelihood of machine breakdown. An experiment is presented which shows the performance of a number of heuristics in the form of dispatching disciplines under different scheduling conditions which are determined by the scheduling period and the level of uncertainty in the process times and machine breakdowns. Various different measures of performance which could be of importance to management are considered. These include mean ratio of flow time to process time, mean queueing time, mean lateness, percentage of jobs late and net CPU times required to generate schedules in the simulation process. Results are presented showing the relationship between the performance of the heuristics relative to the different measures...

Job-shop scheduling: an investigation in constraint-directed reasoning

Abstract: 1. Introduction I___-This paper describes ISIS-II*, a constraint-directed reasoning system for the scheduling of factory job-shops. ISIS-II takes a heuristic search approach to generating schedules. The key features of ISIS-II's approach is that it can represent and use a variety of different types of constraints to guide the search, and is able to selectively relax conflicting constraints.

Priority Scheduling Rules for Repairable Inventory Systems

Abstract: Improved priority scheduling rules are presented for a repair shop supporting a multi-item repairable inventory system with a hierarchical product structure. A variety of scheduling rules are evaluated using a simulation of a representative shop and product structure. The results indicate that dynamic rules which use inventory status information perform better than other dynamic or static rules which ignore inventory status; moreover, dynamic rules which use work-in-process inventory information outperform dynamic rules which ignore work-in-process inventory levels. In the simulation, the use of improved scheduling rules provides performance equivalent to a 20% reduction in spares inventory.

Stochastic Shop Scheduling: A Survey

Abstract: In this paper a survey is made of some of the recent results in stochastic shop scheduling. The models dealt with include: (i) Open shops. (ii) Flow shops with infinite intermediate storage (permutation flow shops). (iii) Flow shops with zero intermediate storage and blocking. (iv) Job shops. Two objective functions are considered: Minimization of the expected completion time of the last job, the so-called makespan, and minimization of the sum of the expected completion times of all jobs, the so-called flow time. The decision-maker is not allowed to preempt. The shop models with two machines and exponentially distributed processing times usually turn out to have a very nice structure. Shop models with more than two machines are considerably harder.

Scheduling the Open Shop to Minimize Mean Flow Time

Abstract: It is shown that the problem of scheduling a two-processor n-job open shop nonpreemptively in order to minimize mean flow time is NP-complete even if input length is measured by the sum of the task lengths. The proof is similar in approach to that used by Garey, Johnson and Sethi to show NP-completeness of the two-processor flow shop mean flow problem. We assume previous results from their paper where possible and concentrate on those elements of the proof that are distinct from theirs.In addition, bounds are derived for the mean flow times of arbitrary and shortest processing time (SPT) first schedules for m-processor n-job systems in terms of the mean flow time of an optimal schedule.

Unit Execution Time Shop Problems

Abstract: The problem of preemptively and nonpreemptively scheduling a set of n independent jobs on an m machine open shop, flow shop or job shop is studied. It is shown that the problem of constructing optimal mean finishing time preemptive and nonpreemptive schedules is NP-hard. These problems are not only NP-hard in the strong sense, but remain NP-hard even when all nonzero tasks have identical execution time requirements. These results will also apply to the case when the problem is to construct an optimal finish time preemptive and nonpreemptive schedule for a flow shop or a job shop. We also discuss the problem of constructing no-wait schedules for these problems.

An Efficient Optimal Algorithm for the Two-Machines Unit-Time Jobshop Schedule-Length Problem

Abstract: The problem of scheduling a two-machine unit-operation-time jobshop to complete all jobs as rapidly as possible is shown to be solved by the following rule. Select for service from available jobs at each stage one with longest remaining processing time. The running time and storage space of the rule are both linear functions of the total number of operations, thereby establishing that the problem belongs to P.

n jobs and m machines job-shop problems with sequence-dependent set-up times

Abstract: This paper presents a mathematical model based on the branch-and-bound technique to solve static scheduling problems involving n jobs and m machines where the objective is to minimize the cost of setting up the machines. Set-up times are sequence dependent and not included in processing times. There is a finite non-zero cost associated with setting the machines which is different for each machine. It is further assumed that the routing may be different for different jobs and a job may return to a machine more than once.

A Methodology to Describe Operating Characteristics of Assembly Systems

Abstract: A methodology for describing the operating characteristics of low volume (small lot) assembly systems is presented in this paper. Analytical models indicate that the deterministic assembly system is equivalent to a flow shop. A numerical approximation technique is applied to develop measures of performance for probabilistic systems. Results include identification of metering stations which control work flow and of potential inconsistencies between productivity and flow-time objectives. The impacts of scheduling policies that determine the intervals at which “mainframes” are launched into assembly, and the due dates for parts, are investigated. The strategy of setting due dates for parts is shown to have a significant influence over work-in-process levels and schedule performance in probabilistic systems.

Note-On Anomalies in Dynamic Ratio Type Scheduling Rules: A Clarifying Analysis

Abstract: Previous authors have shown that dynamic ratio scheduling rules do not always behave as intended. A recent proposal by Adam and Surkis Adam, N. R., J. Surkis. 1980. Priority update intervals and anomalies in dynamic ratio type job shop scheduling rules. Management Sci.26 12, December 1227-1237. to correct such anomalies is shown to be in error. The reason why such anomalies occur is clarified and a rule which prevents such anomalies is presented.

A New Algorithm of Solving the Flow — Shop Problem

Abstract: The general flow — shop problem indicated by n|m|F|Cmax, can be formulated as follows. Each of n jobs J,…,Jn has to be processed on m machines M1,…,Mm in that order. Job Jj, j=1,…,n, thus consists of a sequence of m operations oj1..,,…,0. jm0jk corresponds to the processing of Jj on Mk during a processing time Pjk We want to find a processing order on each machine Mk such that the time required to complete all jobs is minimized. If the processing order is assumed to be the same on each machine, the resulting problem is called the permutation flow — shop problem, and indicated by n|m|F|Cmax.

Complexity and Solutions of Some Three-Stage Flow Shop Scheduling Problems

Abstract: It is well known that the minimal length non-preemptive scheduling problem for the general three-stage flow shop is NP-complete. This paper presents a study of a special type of flow shop in which a particular stage of each job is the longest (or the shortest as the case may be). In most cases, it is found that the problem remains strongly NP-complete. In other cases, polynomial scheduling algorithms are presented.

On n-job, 2-machine flow-shop scheduling problem with arbitrary time lags and transportation times of jobs

Abstract: This short paper gives solution algorithm of obtaining an optimal sequence to give minimum total elapsed time in a 'n·job, 2-machine' flow-shop scheduling problem in which jobs involve Arbitrary Time Lags (Le. Start Lags and Stop Lags) and Transportation Times. All the times (processing Times, Arbitrary Lags, and Transportation times) are given prior and are of deterministic; nature.

Deterministic and stochastic scheduling : proceedings of the NATO Advanced Study and Research Institute on Theoretical Approaches to Scheduling Problems, held in Durham, England, July 6-17, 1981

Abstract: I. Advanced Study Institute Proceedings.- Worst-Case Analysis of Heuristic Algorithms for Scheduling And Packing.- Recent Developments in Deterministic Sequencing and Scheduling: A Survey.- On Scheduling with Release Times and Deadlines.- Scheduling Uniform Machines with Release Times, Deadlines and Due Times.- Preemptive Scheduling of Precedence-Constrained Jobs on Parallel Machines.- Forwards Induction and Dynamic Allocation Indices.- Multiserver Stochastic Scheduling.- Stochastic Shop Scheduling: A Survey.- Multi-Server Queues.- Queueing Networks and their Computer System Applications: An Introductory Survey.- Stationary Properties of timed Vector Addition Systems.- The Multiproduct lot Scheduling Problem.- An Introduction to Proof Techniques for Bin-Packing Approximation Algorithms.- A Stochastic Approach to Hierarchical Planning and Scheduling.- On Stochastic Analysis of Project-Networks.- II. Advanced Research Institute, Proceedings.- Probabilistic Analysis of the Lpt Processor Scheduling Heuristic.- Sequential Project Selection (Multi-Armed Bandits) and the Gittins Index.- Dominant Strategies in Stochastic Allocation and Scheduling Problems.- On the Computational Complexity of Stochastic Scheduling Problems.- Deterministic and Stochastic Scheduling Problems with Treelike Precedence Constraints.- On the Evaluation of Non-Preemptive Strategies in Stochastic Scheduling.- Sequential Open-Loop Scheduling Strategies.- On the Delay Functions Achievable by Non-Preemptive Scheduling Strategies in M/G/L Queues.- Modelling for Multiprocessor Projects.- Addresses of Authors.- Name Index.

On Scheduling in a Semi-Ordered Flow Shop without Intermediate Queues

Abstract: The dynamic programming solution offered is of complexity O(n 2) and is a significant improvement over the implicit enumeration procedure previously suggested by Arora and Rana in an article in the September 1980 issue of TRANSACTIONS.

Estimating Job Flow-Times in a Job Shop for Contractually Negotiated Due-Dates

Abstract: One of the most important aspects of job shop planning is the contract negotiation process. In this process the job shop vendor must negotiate a job due-date acceptable to both job shop and the customer. Failure to obtain reasonably accurate predictions of the job completion time can result in penalties and/or lost future sales for the job shop. As such, estimation of job flow-times is critical to successful job shop operation. This paper presents a network modelling approach to the difficult and complex task of estimating job flow-times not previously presented in the literature. The approach is demonstrated via a case example where the system model is developed as a Q-GERT network and simulation results are obtained.

Scheduling in Proportionate Flowshops.

Abstract: : It is well known that except in the case of makespan problems, there are hardly and analytical results for flowshop problems. This paper considers of a class of flowshop problems where jobs processing time at a machine is proportionate to the processing time on the first machine. The authors show that for the pre-emptive version of the problem, in order to minimize and regular measure of performance, it is sufficient to consider permutation schedules. Also, results for various other measure are derived. A characterization of the optimal solution for the weighed tardiness problem is derived which is analogues to its counterpart in the single machine case. It is indicated as how this characterization may be used to develop heuristics for flowshop problems.

Large scale implementation of a time oriented vehicle scheduling model

Abstract: The objective of this research project was the development of a vehicle scheduling model with three special properties: 1) the ability to solve large scale vehicle scheduling problems with time window and time dependent customer demand constraints; 2) the capability of being integrated within the Computer Assisted Routing, Scheduling, and Dispatching/Management Information System (CARSD/MIS) currently being developed by the Transportation Administration of Dade County, Florida for UMTA as a prototype for other coordinated paratransit services; and 3) the ability to provide operational solutions to vehicle scheduling problems obtained from the research literature and from CARSD/MIS database. This document reports the development of a time oriented vehicle scheduling model. The model is unique in its ability to incorporate easily time window and time dependent customer demand constraints. Solutions to the model are obtained through the use of a branch and bound procedure. A disjunctive graph model, similar to those employed in activity and job shop scheduling, is used in the solution procedure to obtain bounding information. The efficacy of this procedure is demonstrated on vehicle scheduling problems obtained from the research literature. The authors state that although the current implementation of the time oriented vehicle scheduling algorithm has been developed to meet the operational requirements of the scheduling module of the CARSD/MIS system, delays in the CARSD/MIS project prevented the required operational interface and testing.

Determination of appropriate dynamic slack sequencing rules for an industrial flow shop via discrete simulation

Abstract: This paper presents an application of combined discrete and network simulation modelling to determine and validate an appropriate sequencing technique for a modified flow shop. The research was based upon a study of a modified flow shop at the International Business Machines, Federal Systems Division (IBM/FSD), Manassas, Virginia, manufacturing Facility. The company's concerns were directed towards enhancing the real-time scheduling of a man and machine dependent flow shop where meeting customer due dates was vital. In this manufacturing facility it is necessary to rework all parts that do not initially meet stringent quality control specifications until those parts do meet those quality limits. Therefore another reason for analyzing different sequencing rules was the necessity to better control the rework activity.The sequencing technique currently used at this facility is based on Earliest Due Date scheduling. With the cooperation of the production control organization at IBM/FSD, Manassas, a simulation study was performed in order to determine if an enhancement to the current system could be found. The objective of the research was to determine which due date based sequencing technique would best meet the overriding production control criteria of the IBM/FSD flow shop. The company's production control objectives were to minimize number of tardy jobs, total amount of job tardiness, and total amount of in--process inventory.The flow shop was modelled using SLAM simulation language. The flow shop was both machine and man dependent requiring both entities to be modelled. A time-consuming task encountered in the development of this model, and with the development of many other simulation models which attempt to represent real world systems, was the task of obtaining data in the proper format to analytically determine the control parameters for the model. This paper presents and discusses some of the difficulties encountered with the data interpretation.Also included in the paper is a discussion of the due date based sequencing techniques studied and the usefulness of simulation to determine and validate the appropriate sequencing technique.