113 research outputs found
Minimizing the condition number of a positive definite matrix by completion
No full textElsner L, He C, Mehrmann V. Minimizing the condition number of a positive definite matrix by completion. Numerische Mathematik. 1994;69(1):17-23.We consider the problem of minimizing the spectral condition number of a positive definite matrix by completion: [GRAPHICS] where A is an n x n Hermitian positive definite matrix, B a p x n matrix and X is a free p x p Hermitian matrix. We reduce this problem to an optimization problem for a convex function in one variable. Using the minimal solution of this problem we characterize the complete set of matrices that give the minimum condition number
Proposal measures for the reactivation of industrial degraded areas in the case of the Zasavje statistical region
No full textV magistrskem delu smo se dotaknili problematike industrijskih degradiranih območij v Sloveniji. Sprva smo pregledali različne definicije degradiranega območja, tako tuje kot tudi slovenske. Pregledali in proučili smo slovenske in evropske iniciative na temo degradiranih območij in raziskali različna merila za določitev le teh. Sledil je pregled različnih ukrepov in strategij. Pregledali smo tudi številne primere dobrih praks prenove degradiranih industrijskih območij in poizkušali ugotoviti, na kakšen način so se lotili prenove. V magistrski nalogi smo v aplikativnem delu obravnavali Zasavsko statistično regijo, ki velja za najbolj degradirano regijo v Sloveniji. Regijo smo podrobno proučili in s pomočjo spletne aplikacije za vodenje evidence FDO poiskali industrijska degradirana območja v Zasavski regiji. Območja smo si ogledali na terenu in jih podrobno analizirali, izvedli smo tudi polstrukturiran intervju z nekaterimi lastniki zemljišč. Raziskava je pokazala, da je večina območij v lasti pravnih oseb, nekaj območij pa je v javni lasti. V zaključku naloge smo nato predlagali še ukrepe za reaktivacijo degradiranih industrijskih območij.In this master’s thesis the author discussed the problems of industrial degraded areas in Slovenia. The first task was to review various definitions of the degraded area, both foreign and Slovenian. The next step was to review and study Slovenian and European initiatives in degraded areas and investigate various criteria for determining degraded areas, which was followed by an overview of various measures and strategies. Several examples of good practice in the field of renovation of degraded industrial sites were examined, whereby the author tried to determine the renewal approach that was applied. In the empirical part of this thesis, issues in Zasavje statistical region, which is considered to be the most degraded region in Slovenia, were addressed. The region was examined in detail and industrial degraded areas in Zasavje region were determined by means of an online record-keeping application FDO (Functional degraded areas). The author has visited the examined areas, analysed them in detail, and conducted some semi-structured interviews with some landowners. The research has shown that the majority of the areas is owned by legal entities and that some areas are publicly owned. In the conclusion, the author suggested the measures that should be taken to reactivate degraded industrial sites
Relation of skewness factor and convection velocity in turbulent boundary layer
No full textThe paper is devoted to prove the relation between skewness factor and convection velocity in turbulent boundary layer. It appears that skewness factor can be used as an indicator of convection velocity of coherent structures, which is not always equal to the average flow velocity. The analysis has been performed based upon velocity profiles measured with hot-wire technique in turbulent boundary layer with pressure gradient corresponding to turbomachinery conditions. The results show that the cross product term of skewness factor decomposed by spectral filtering, which is also alternative measure of amplitude modulation, describes the convection velocity in zero pressure gradient turbulent boundary layer
Über Eigenwerteinschließungen mit Hilfe von Gerschgorin-Kreisen
No full textElsner L. Über Eigenwerteinschließungen mit Hilfe von Gerschgorin-Kreisen. Zeitschrift für angewandte Mathematik und Mechanik. 1970;50(6):381-384.Let the union of some Gerschgorin-disks of a matrix A be separated from the other disks by a circle of radius r and center Gamma. Medley and Varga have characterized the minimal r, which can be achieved by diagonal transformations of A and fixed Gamma. It is shown that this result can easily be proved with methods used in an earlier paper of the author. In addition, the maximal radius is characterized, easily computable bounds are given and it is shown, that A and the transposed matrix AT have the same optimal radii.Die Vereinigung gewisser Gerschgorin-Kreise einer Matrix A sei durch einen Kreis vom Radius r und Mittelpunkt Gamma von den übrigen Gerschgorin-Kreisen getrennt. Medley und Varga haben das minimale r, das bei festem Gamma durch Diagonaltransformationen von A erreicht werden kann, charakterisiert. Es wird gezeigt, daß dieses Ergebnis mit den in einer früheren Arbeit des Autors benutzten Methoden leicht bewiesen werden kann. Außerdem wird der maximale Radius charakterisiert, praktisch verwendbare Abschätzungen angegeben und gezeigt, daß A und die transponierte Matrix AT die gleichen optimalen Radien haben
Flooded Edge Gateways
No full textIncreasing numbers of internet-compatible devices, in particular in the context of IoT, usually cause increasing amounts of data. The processing and analysis of a continuously growing amount of data in real-time by means of cloud platforms cannot be guaranteed anymore. Approaches of Edge Computing decentralize parts of the data analysis logics towards the data sources in order to control the data transfer rate to the cloud through pre-processing with predefined quality-of-service parameters. In this paper, we present a solution for preventing overloaded gateways by optimizing the transfer of IoT data through a combination of Complex Event Processing and Machine Learning. The presented solution is completely based on open-source technologies and can therefore also be used in smaller companies.Steigende Zahlen Internet-fähiger Geräte, besonders im Kontext des Internet der Dinge (IoT), verursachen zunehmend große Mengen an Daten. Die Verarbeitung und Analyse einer stetig steigenden Datenmenge mit Hilfe von Cloud-Plattformen kann in Echtzeit nicht mehr garantiert werden. Ansätze des Edge Computing dezentralisieren Teile der Datenanalyselogik in Richtung der Datenquellen, um den Datendurchsatz zur Cloud durch eine Vorverarbeitung im Rahmen vordefinierter Quality-Of-Service-Parameter zu kontrollieren. In dieser Arbeit stellen wir eine Lösung zur Prävention überladener Gateways vor, indem wir die Übertragung von IoT-Daten durch eine Kombination von Complex Event Processing und maschinelles Lernen optimieren. Die vorgestellte Lösung basiert vollständig auf Open-Source-Technologien und kann somit auch in kleineren Unternehmen angewendet werden
Advanced hot rolling strategies for IF and TRIP steels
No full textSteel producers are forced to reduce the production cost on the one hand and increase the performances of the products on the other hand, to maintain or even increase their market share. A likely method to save on production costs is to cut down the rather long production chain for conventional cold rolled strip, and to substitute certain cold rolled steel grades by hot rolled steel. Certainly this can rarely be achieved for exposed parts, requiring a perfect surface finish, whereas for unexposed parts, e.g. structural components, with lower surface requirements, the use of hot strips might be a cost saving alternative. The aim of this thesis is to contribute to the understanding of the microstructure and texture development of deep-drawing steels during ferritic rolling, subsequent cold rolling and annealing on the one hand and to appraise the possible improvement of the mechanical and deep-drawing properties on the other hand. On the basis of these results guidelines for the industrial production of ferritic rolled hot strip are proposed. Furthermore, a new hot rolling strategy for the production of hot rolled low alloy TRIP steel is proposed and the development of the microstructure and the mechanical properties to be obtained are investigated in a set plain strain compression test using a hot deformation simulator.Aerospace Engineerin
Abstinence of Former Pervitin Users
No full textBakalářská práce je zaměřena na problematiku drogové závislosti. Autorka přibližuje historii, druhy, příčiny a průběh vzniku závislosti. Poukazuje na potřebu prevence vzniku drogové závislosti. Také se zabývá možnostmi léčby a vymezuje roli sociálního pracovníka. V praktické části se autorka zaměřuje na abstinenci od pervitinu a riziko recidivy. Výzkum je realizován kvalitativní metodou prostřednictvím polostrukturovaných rozhovorů s bývalými pacienty psychiatrické nemocnice s diagnózou závislosti na pervitinuThe bachelor work is focused on the issue of drug dependence. The author describes the history, classification, causes and origins of dependence. She points to the need for prevention of drug dependence. The work also deals with the possibilities of healing and defines the role of social worker. In the practical part, the author focuses on pervitin abstinence and the risk of relapse. The research is carried out by qualitative method of semi-structured interviews with former patients of Psychiatric Hospital with pervitin dependence diagnosis.Ústav zdravotnických vě
Convex combinations of matrices — Full rank characterization
No full textAbstractLet A1,…, Ak be complex n-by-m matrices. Using the notion of a block P-matrix, introduced recently by Elsner and the second author, a characterization of the full rank property of all convex combinations of A1,…, Ak is derived
Symmetric schemes for computing the minimum eigenvalue of a symmetric Toeplitz matrix
No full textde Dedicated to Ludwig Elsner on the occasion of his th birthday In and W Mackens and the present author presented two generaliza tions of a method of Cybenko and Van Loan for computing the smallest eigenvalue of a symmetric positive de nite Toeplitz matrix Taking advan tage of the symmetry or skew symmetry of the corresponding eigenvector both methods are improved considerabl
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