Resource Management in Machine Scheduling Problems: A Survey

The paper is a survey devoted to job scheduling problems with resource allocation. We present the results available in the scientific literature for commonly used models of job processing times and job release dates, i.e., the models in which the job processing time or the job release date is given as a linear or convex function dependent on the amount of the additional resource allotted to the job. The scheduling models with resource dependent processing times or resource dependent release dates extend the classical scheduling models to reflect more precisely scheduling problems that appear in real life. Thus, in this paper we present the computational complexity results and solution algorithms that have been developed for this kind of problems

Neighbourhood Properties in Some Single Processor Scheduling Problem with Variable Efficiency and Additional Resources

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

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

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 NPhard, 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

Variations of genotypes of Vicia species as influenced by seed phenolic compounds and antioxidant activity

The phenolic compounds and antioxidant activity of different Vicia species, which are cultivated in different areas of Turkey, and the diversity between analysed characters were investigated. For this purpose, 9 genotypes from three Vicia species: common vetch (Vicia sativa L.), Hungarian vetch (Vicia pannonica Crantz.) and Narbon vetch (Vicia narbonensis L.), were used. The experiment was carried out to determine total phenolic content (TPC), content of individual phenolic compounds, to determine ABTS(center dot+) and DPPH center dot scavenging activity and ferric-reducing antioxidant power (FRAP) in methanol and acetone extracts of seeds. The TPC of vetch extracts was in range 11.18-30.42 mg GAE g(-1) (in methanol extract) and 17.05-59.88 mg GAE g(-1) (in acetone extract). Two V. sativa genotypes Cvoe and Cvke stood out among the others with regard to high TPC and antioxidant activity. They also had the highest content of individual hydroxybenzoic acids and flavones. All extracts of V. narbonensis genotypes were characterised by absence of flavones and low TPC and antioxidant activity. GGE biplot analysis revealed the differences of Vicia genotypes based on phenolic compounds and antioxidant activity. The significant correlations among TEAC, FRAP and DPPH center dot scavenging activity and the content of hydroxybenzoic acids were found in both methanol and acetone extracts (P < 0.01). The genotypes were divided into three clusters in acetone extract and two clusters in methanol extract with similarity above 60% in each group by a hierarchical cluster analysis. These results demonstrated that the genotypic differences of Vicia species in terms of TPC and antioxidant activity can be a tool for feed technology studies for animal nutrition, animal welfare and meat quality.Council of Higher Education (YOK) in TurkeyH. Hulya Orak thanks Council of Higher Education (YOK) in Turkey for financial support for her stay in Institute of Animal Reproduction and Food Research of the Polish Academy of Sciences in Olsztyn

Structure and Magnetic Properties of Fe-B-La-Al Alloy

Nanocrystalline magnetic materials are of great interest in order to meet the needs of electronics and electrical engineering. There are many possibilities to modify the synthesis parameters and chemical composition in order to obtain the most desirable magnetic properties and microstructure. The paper discusses an iron-based alloy with the addition of boron lanthanum and aluminium. The alloy was obtained by induction melting and casting with a melt-spinner. The main purpose of the work was to analyze the structure and properties of both the starting alloys in the form of ingots and the obtained tapes. X-ray diffraction (XRD), scanning electron microscopy (SEM), vibration magnetometry (VSM) and microhardness measurements using the Vickers method were carried out