952 resultados para Gröbner Basis
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Methodological, theoretical and technological bases of the new branch standard of Ukraine higher education which regulates preparation process of masters - professionals in the information area and information analysts are considered. The new systemological knowledge-oriented technologies developed in KNURE which considerably surpass foreign analogues are put as the basis of training.
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Basic concepts for an interval arithmetic standard are discussed in the paper. Interval arithmetic deals with closed and connected sets of real numbers. Unlike floating-point arithmetic it is free of exceptions. A complete set of formulas to approximate real interval arithmetic on the computer is displayed in section 3 of the paper. The essential comparison relations and lattice operations are discussed in section 6. Evaluation of functions for interval arguments is studied in section 7. The desirability of variable length interval arithmetic is also discussed in the paper. The requirement to adapt the digital computer to the needs of interval arithmetic is as old as interval arithmetic. An obvious, simple possible solution is shown in section 8.
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2000 Mathematics Subject Classification: 16R10, 16R20, 16R50
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The persistence of Salmonella spp. in low moisture foods is a challenge for the food industry as despite control strategies already in place, notable outbreaks still occur. The aim of this study was to characterise isolates of Salmonella, known to be persistent in the food manufacturing environment, by comparing their microbiological characteristics with a panel of matched clinical and veterinary isolates. The gross morphology of the challenge panel was phenotypically characterised in terms of cellular size, shape and motility. In all the parameters measured, the factory isolates were indistinguishable from the human, clinical and veterinary strains. Further detailed metabolic profiling was undertaken using the biolog Microbial ID system. Multivariate analysis of the metabolic microarray revealed differences in metabolism of the factory isolate of S.Montevideo, based on its upregulated ability to utilise glucose and the sugar alcohol groups. The remainder of the serotype-matched isolates were metabolically indistinguishable. Temperature and humidity are known to influence bacterial survival and through environmental monitoring experimental parameters were defined. The results revealed Salmonella survival on stainless steel was affected by environmental temperatures that may be experienced in a food processing environment; with higher survival rates (D25=35.4) at temperatures at 25°C and lower humidity levels of 15% RH, however a rapid decline in cell count (D10=3.4) with lower temperatures of 10°C and higher humidity of 70% RH. Several resident factories strains survived in higher numbers on stainless steel (D25=29.69) compared to serotype matched clinical and veterinary isolates (D25=22.98). Factory isolates of Salmonella did not show an enhanced growth rate in comparison to serotype matched solates grown in Luria broth, Nutrient broth and M9 minimal media indicating that as an independent factor, growth was unlikely to be a major factor driving Salmonella persistence. Using a live / dead stain coupled with fluorescence microscopy revealed that when no longer culturable, isolates of S.Schwarzengrund entered into a viable nonculturable state. The biofilm forming capacity of the panel was characterised and revealed that all were able to form biofilms. None of the factory isolates showed an enhanced capability to form biofilms in comparison to serotype-matched isolates. In disinfection studies, planktonic cells were more susceptible to disinfectants than cells in biofilm and all the disinfectants tested were successful in reducing bacterial load. Contact time was one of the most important factors for reducing bacterial populations in a biofilm. The genomes of eight strains were sequenced. At the nucleotide and amino acid level the food factory isolates were similar to those of isolates from other environments; no major genomic rearrangements were observed, supporting the conclusions of the phenotypic and metabolic analysis. In conclusion, having investigated a variety of morphological, biochemical and genomic factors, it is unlikely that the persistence of Salmonella in the food manufacturing environment is attributable to a single phenotypic, metabolic or genomic factor. Whilst a combination of microbiological factors may be involved it is also possible that strain persistence in the factory environment is a consequence of failure to apply established hygiene management principles.
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The article attempts to answer the question whether or not the latest bankruptcy prediction techniques are more reliable than traditional mathematical–statistical ones in Hungary. Simulation experiments carried out on the database of the first Hungarian bankruptcy prediction model clearly prove that bankruptcy models built using artificial neural networks have higher classification accuracy than models created in the 1990s based on discriminant analysis and logistic regression analysis. The article presents the main results, analyses the reasons for the differences and presents constructive proposals concerning the further development of Hungarian bankruptcy prediction.
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The Leontief input-output model is widely used to determine the ecological footprint of consumption in a region or a country. It is able to capture spillover environmental effects along the supply change, thus its popularity is increasing in ecology related economic research. These studies are static and the dynamic investigations are neglected. The dynamic Leontief model makes it possible to involve the capital and inventory investment in the footprint calculation that projects future growth of GDP and environmental impacts. We show a new calculation method to determine the effect of capital accumulation on ecological footprint. Keywords: Dynamic Leontief model, Dynamic ecological footprint, Environmental management, Allocation method
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In our study we rely on a data mining procedure known as support vector machine (SVM) on the database of the first Hungarian bankruptcy model. The models constructed are then contrasted with the results of earlier bankruptcy models with the use of classification accuracy and the area under the ROC curve. In using the SVM technique, in addition to conventional kernel functions, we also examine the possibilities of applying the ANOVA kernel function and take a detailed look at data preparation tasks recommended in using the SVM method (handling of outliers). The results of the models assembled suggest that a significant improvement of classification accuracy can be achieved on the database of the first Hungarian bankruptcy model when using the SVM method as opposed to neural networks.
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A szervezet dolgozói között kiemelt fontosságúak a vezetők, hiszen döntéseikkel, működésükkel a szervezet életét közvetlenül, és sokszor hosszú távra befolyásolják. Annak a vállalatnak, mely megtartani, növelni szeretné piaci pozícióját, különös hangsúlyt kell fektetnie vezetőinek kiválasztására, a későbbiekben pedig fejlesztésére. A szerző cikkében azt mutatja be, hogy a közgazdászképzettséggel rendelkező vezetők iránti munkaerő-piaci kereslet (a HVG-hirdetések elemzése alapján) milyen minőségi jellemzőket mutatott 2000–2009 között. A szerző részletesen ismerteti az eredményeket, melyek értelmezéséhez a Spencer és munkatársai által kidolgozott kompetenciamodell saját továbbfejlesztett változatát használja fel. Kitekintés céljával a magyar eredmények mellett bemutatja, hogy egy más gazdasági struktúrával, kultúrával rendelkező országban hogyan alakultak a vezetőkkel szemben támasztott kompetencia-elvárások. Az eredmények – melyeket más hazai felmérések is alátámasztanak – azt tükrözik, hogy a magyar vezetőkkel szemben támasztott munkaerő-piaci kompetencia-elvárások eltérnek a szakmai várakozásoktól és élesen eltérő képet mutatnak a The Economist hirdetéselemzésének eredményétől. _________ The thesis that the most important factor which determines the competitiveness of future companies is the quality of human resources has received increasingly more emphasis in the literature on management. The managers of organizations have a key role since they can directly influence the life of the organization by their decisions and work, often for a long term. Therefore, a company which intends to maintain or improve its market position should place special emphasis on the selection, and later on the development of its managers. In the present paper the author presents the characteristic features of job market demand for managers with qualifications in economics between 2000 and 2009 (on the basis of the analysis of job advertisements published in the economic weekly paper Heti Világgazdaság). The author gives a detailed analysis of the results using the competence model developed by Spencer et al. and further developed by the author. In addition to the Hungarian results, the paper also provides an overview of how managers are selected in a country with a different economic structure and culture. The results – also supported by other surveys conducted in Hungary – demonstrate that the competence expectations of the job market for Hungarian managers fail to meet professional expectations; the picture is sharply different from what the analysis of job advertisements published in The Economist show, and the competence expectation changed very little, though quite strikingly, over the period under discussion.
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Iridescent blue leaf coloration in four Malaysian rain forest understory plants, Diplazium tomentosum Bl. (Athyriaceae), Lindsaea lucida Bl. (Lindsaeaceae), Begonia pavonina Ridl. (Begoniaceae), and Phyllagathis rotundifolia Bl. (Melastomataceae) is caused by a physical effect, constructive interference of reflected blue light. The ultrastructural basis for this in D. tomentosum and L. lucida is multiple layers of cellulose microfibrils in the uppermost cell walls of the adaxial epidermis. The helicoidal arrangement of these fibrils is analogous to that which produces a similar color in arthropods. In B. pavonina and P. rotundifolia the blue-green coloration is caused by parallel lamellae in specialized plastids adjacent to the abaxial wall of the adaxial epidermis. The selective advantage of this color production, if any, is unknown.
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Iridescent blue leaf coloration in two neotropical ferns, Danaea nodosa (L.) Sm. (Marattiaceae) and Trichomanes elegans L. C. Rich. (Hymenophyllaceae), is caused by thin film constructive interference. The ultrastructural basis for the film in D. nodosa is multiple layers of cellulose microfibrils in the adaxial cell walls of the adaxial epidermis. The apparent helicoidal arrangement of the fibrils is analogous to similar color production in arthropods. In T. elegans the blue-green coloration is caused by the remarkably uniform thickness and arrangement of grana in specialized chloroplasts adjacent to the adaxial wall of the adaxial epidermis. The selective advantage of this color production, if any, is unknown but apparently different from that previously studied in Selaginella.
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The iridescentb lue color of several Selaginellasp ecies is caused by a physical effect, thinfilm interference.P redictionsf or a model film have been confirmedb y electronm icroscopyo f S. willdenowaEnid S. uncinataF. or the latters pecies iridescencec ontributest o leaf absorption at wavelengths above 450 nm and develops in environments enriched with far-red (730 nm) light. This evidence supports the involvement of phytochrome in the developmental control of iridescence.
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Iridescent colour, caused by physical effects (thin-film interference, diffraction and Tyndall scattering), is relatively common in animals but exceedingly rare among plants1. Some benthic marine algae produce blue to violet iridescence2,3, and the upper leaf surfaces of a few vascular plants from the shady environments of humid tropical forests are iridescent blue4–6. Blue fruit colour has been assumed to be caused by anthocyanins7. A survey of such fruits (26 species in 18 genera) in Costa Rica, India, Florida and Malaysia, showed this to be the case, except for the iridescent colour in fruits of Elaeocarpus angustifolius Blume (Elaeocarpaceae). There I show that the colour is caused by a remarkable structure in the epidermis, and provide evidence for its selective advantage.