Decision Making in Manufacturing and Services
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ISSN 1896-8325
e-ISSN: 2300-7087
Issue Date
2011
Volume
Vol. 5
Number
No. 1/2
Description
Journal Volume
Decision Making in Manufacturing and Services
Vol. 5 (2011)
Projects
Pages
Articles
Neighbourhood properties in some single processor scheduling problem with variable efficiency and additional resources
(2011) Gorczyca, Mateusz; Janiak, Adam; Janiak, Władysław
In the paper, we consider a problem of scheduling a set of tasks on a single processor. Each task must be preprocessed before it can be started on a processor. The efficiency of preprocessing is variable, i.e., the rate of the task preprocessing depends on the amount of continuously divisible resource allotted to this task. This dependency is given by concave, continuous, non-negative and strictly increasing function of the resource amount. The total consumption of resource at each moment is upper bounded. The objective is to minimize the maximum task completion time. The considered problem is NP-hard. Such a problem appears, e.g., in steel mill systems, where ingots (before hot rolling on the blooming mill) have to achieve the required temperature in the preheating process in soaking pits. Some new properties of the problem are proved. These properties are used to construct the procedure for evaluation of the neighbourhood. The procedure is proposed to improve the efficiency of algorithms based on the neighbourhood concept, such as metaheuristics. The computational experiment is conducted to examine the efficiency of the proposed procedure. The described approach can be easily used in the other discrete-continuous scheduling problems.
Scheduling problems with learning and ageing effects: a survey
(2011) Janiak, Adam; Krysiak, Tomasz; Trela, Radosław
In recent years, many papers concerning scheduling problems with simultaneous learning and ageing effects were published. In this paper, the state of the art of research concerning these problems is presented. In order to facilitate understanding this subject, the scheduling problems where these effects occur separately, are firstly explained. Then, the papers devoted to scheduling problems combining the effects of learning and ageing are discussed. Particular attention was paid on practical applications of the considered scheduling problems. After thorough analysis it turned out that both scheduling problems with learning effect, and with ageing effect, as well as, in particular, the problems with models merging learning and ageing effects do not have any reasonable real-life applications. This is because the learning and ageing effects are in general long time horizon phenomena observed in repetitive systems and scheduling theory concerns either with repetitive short-horizon planning problems or single long-horizon projects. Therefore, there is no sense to continue research considering these scheduling problems from practical (computer engineering, automatic control, technical and economical) point of view, unless such reasonable real-life example appears.
Scheduling jobs with linear model of simultaneous ageing and learning effects
(2011) Janiak, Adam; Lichtenstein, Maciej; Rusoń, Agata
In the paper, we introduce some new scheduling model in which learning and aging effects are both considered simultaneously. In this model the actual processing time of the jobs depends only on its position in a schedule and can be described by the piecewise linear function. For single-processor problem with introduced model, we show that the problem of minimizing the makespan criterion for independent jobs with release dates is strongly NP-hard, but some special cases of this problem are polynomially solvable. Based on those special cases, we propose 4 heuristic algorithms and we experimentally examine their usefulness for solving the general problem.
Extended model formulation of the proportional lot-sizing and scheduling problem with lost demand costs
(2011) Kaczmarczyk, Waldemar
We consider mixed-integer linear programming (MIP) models of production planning problems known as the small bucket lot-sizing and scheduling problems. We present an application of a class of valid inequalities to the case with lost demand (stock-out) costs. Presented results of numerical experiments made for the the Proportional Lot-sizing and Scheduling Problem (PLSP) confirm benefits of such extended model formulation.
BPMN - a logical model and property analysis
(2011) Ligęza, Antoni
Business Process Modeling Notation has become a powerful and widely accepted visual language for modeling business processes. Despite its expressive power and high usability, a weak point of BPMN is the lack of formal semantics and difficulties with assuring correctness of the overall process. In this paper an attempt is made towards investigation and development of foundations for a logical, declarative model for BPMN. Such model should enable formal analysis of desired properties referring to correct operation of Business Processes modeled with use of BPMN.