1,622 research outputs found
How the structure of precedence constraints may change the complexity class of scheduling problems
This survey aims at demonstrating that the structure of precedence
constraints plays a tremendous role on the complexity of scheduling problems.
Indeed many problems can be NP-hard when considering general precedence
constraints, while they become polynomially solvable for particular precedence
constraints. We also show that there still are many very exciting challenges in
this research area
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Single machine scheduling with a generalized job-dependent cumulative effect
We consider a single machine scheduling problem with changing processing times. The processing conditions are subject to a general cumulative effect, in which the processing time of a job depends on the sum of certain parameters associated with previously scheduled jobs. In previous papers, these parameters are assumed to be equal to the normal processing times of jobs, which seriously limits the practical application of this model. We further generalize this model by allowing every job to respond differently to these cumulative effects. For the introduced model, we solve the problem of minimizing the makespan, with and without precedence constraints. For the problem without precedence constraints, we also consider a situation in which a maintenance activity is included in the schedule, which can improve the processing conditions of the machine, not necessarily to its original state. The resulting problem is reformulated as a variant of a Boolean programming problem with a quadratic objective, known as a half-product, which allows us to develop a fully polynomial-time approximation scheme with the best possible running time
Single-machine scheduling with deteriorating jobs under a series-parallel graph constraint
Author name used in this publication: C. T. NgAuthor name used in this publication: T. C. E. Cheng2007-2008 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe
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Single machine scheduling with general positional deterioration and rate-modifying maintenance
We present polynomial-time algorithms for single machine problems with generalized positional deterioration effects and machine maintenance. The decisions should be taken regarding possible sequences of jobs and on the number of maintenance activities to be included into a schedule in order to minimize the overall makespan. We deal with general non-decreasing functions to represent deterioration rates of job processing times. Another novel extension of existing models is our assumption that a maintenance activity does not necessarily fully restore the machine to its original perfect state. In the resulting schedules, the jobs are split into groups, a particular group to be sequenced after a particular maintenance period, and the actual processing time of a job is affected by the group that job is placed into and its position within the group
A common framework and taxonomy for multicriteria scheduling problems with Interfering and competing Jobs: Multi-agent scheduling problems
Most classical scheduling research assumes that the objectives sought are common to all jobs to be
scheduled. However, many real-life applications can be modeled by considering different sets of jobs,
each one with its own objective(s), and an increasing number of papers addressing these problems has
appeared over the last few years. Since so far the area lacks a uni ed view, the studied problems
have received different names (such as interfering jobs, multi-agent scheduling, mixed-criteria, etc), some
authors do not seem to be aware of important contributions in related problems, and solution procedures
are often developed without taking into account existing ones. Therefore, the topic is in need of a common
framework that allows for a systematic recollection of existing contributions, as well as a clear de nition
of the main research avenues. In this paper we review multicriteria scheduling problems involving two or
more sets of jobs and propose an uni ed framework providing a common de nition, name and notation
for these problems. Moreover, we systematically review and classify the existing contributions in terms
of the complexity of the problems and the proposed solution procedures, discuss the main advances, and
point out future research lines in the topic
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Approximation schemes for scheduling on a single machine subject to cumulative deterioration and maintenance
We consider a scheduling problem on a single machine to minimize the makespan. The processing conditions are subject to cumulative deterioration, but can be restored by a single maintenance. We link the problem to the Subset-sum problem (if the duration of maintenance is constant) and to the Half-Product Problem (if the duration of maintenance depends on its start time). For both versions of the problem, we adapt the existing fully polynomial-time approximation schemes to our problems by handling the additive constants
Risk-Based Optimal Scheduling for the Predictive Maintenance of Railway Infrastructure
In this thesis a risk-based decision support system to schedule the predictive maintenance activities, is proposed. The model deals with the maintenance planning of a railway infrastructure in which the due-dates are defined via failure risk analysis.The novelty of the approach consists of the risk concept introduction in railway maintenance scheduling, according to ISO 55000 guidelines, thus implying that the maintenance priorities are based on asset criticality, determined taking into account the relevant failure probability, related to asset degradation conditions, and the consequent damages
Branch and Bound Method to Solve Multi Objectives Function
This paper presents a branch and bound algorithm for sequencing a set of n independent jobs on a single machine to minimize sum of the discounted total weighted completion time and maximum lateness, this problems is NP-hard. Two lower bounds were proposed and heuristic method to get an upper bound. Some special cases were proved and some dominance rules were suggested and proved, the problem solved with up to 50 jobs
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