451 research outputs found

    The Introduction and Application of General Regression Model

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    V práci byl podrobně popsán obecný lineární regresní model, včetně testových statistik pro jednotlivé koeficienty, podmodely, predikce a především testy odlehlých hodnot a pozorování výrazně deformujících model. Byl popsán způsob jak do regresního modelu zahrnout kategoriální proměnné. Tento model byl aplikován na popis saturace fotografických snímků chleba, kde vstupní proměnné byly typ mouky, typ přídavku a koncentrace mouky. Po identifikaci nevhodných pozorování jsme vytvořili matematický model, který má vysoký koeficient determinace a odborníkům z potravinářského průmyslu bude v kombinaci s matematickým modelem barvy a struktury, které nejsou předmětem této práce, sloužit k předběžné identifikaci možného složení chleba.This thesis sumarizes in detail general linear regression model, including testing statistics for coefficients, submodels, predictions and mostly tests of outliers and large leverage points. It describes how to include categorial variables into regression model. This model was applied to describe saturation of photographs of bread, where input variables were, type of flour, type of addition and concntration of flour. After identification of outliers it was possible to create mathematical model with high coefficient of determination, which will be usefull for experts in food industry for preliminar identification of possible composition of bread.

    Object Database in the GlobalsDB Environment

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    Cílem této práce je prozkoumat systém GlobalsDB a s jeho pomocí navrhnou, implementovat a  otestovat knihovnu pro persistenci objektů na platformě Java. Nejprve je uveden přehled existujících  možností, po kterém následuje návrh samotného řešení. V následujících kapitolách je popsána  implementace a testování navrženého řešení. Závěr práce je věnován porovnání výkonu vůči  existujícím řešením.The goal of this thesis is to explore the GlobalsDB database and to design, implement and test an  object persistence library for this database on Java platform. The opening chapters contain a  description of the existing possibilities and subsequently, our own solution is proposed. In the  following chapters, the implementation and testing of the proposed solution is described. Last  chapters compare the performance of the designed solution against its competition.

    Filmy wideo w nauczaniu cudzoziemców słownictwa biologicznego

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    Zadanie pt. Digitalizacja i udostępnienie w Cyfrowym Repozytorium Uniwersytetu Łódzkiego kolekcji czasopism naukowych wydawanych przez Uniwersytet Łódzki nr 885/P-DUN/2014 zostało dofinansowane ze środków MNiSW w ramach działalności upowszechniającej naukę

    Optimization in Engineering Design

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    Cílem práce je ukázat možnosti optimalizačního přístupu pro vybrané základní úlohy inženýrského návrhu, tyto diskutované modely implementovat v GAMSu a provést testovací výpočty. Tyto výpočty jsou provedeny na základě znalostí lineárního a nelineárního programování.The aim of present work is to show possibilities of optimization for special basic examples of engineering design. The discussed models have been implemented in GAMS and the corresponding calculations have been performed. The knowledge of linear and non-linear programming is utilized.

    Least-squares fitting of multivariate data

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    Práce shrnuje základní teorii potřebnou pro odvození aproximace pomocí metody nejmenších čtverců a aplikuje tuto metodu na data z technické praxe. V rámci práce byly vytvořeny programy, v prostředí MATLAB, pro řešení této úlohy. MATLAB už obsahuje několik algoritmů použitelných pro tuto problematiku. Práce zahrnuje porovnání vlastností a testování těchto algoritmů.Thesis sumarizes basic theory required for inference of aproximation using the least squares method and aplicates this method on data obtained from engineering practice. Within thesis were created programs, in MATLAB enviroment, to solve this problem. MATLAB already contains several algorithms, wich are useful for solving this problem. Thesis includes comparsion of properties and test of those algorithms.

    Influence of Polyphenol Extract from Evening Primrose (Oenothera Paradoxa) Seeds on Proliferation of Caco-2 Cells and on Expression, Synthesis and Activity of Matrix Metalloproteinases and Their Inhibitors

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    Evening primrose (Oenothera paradoxa Hudziok) seeds are a rich source of not only a valuable oil containing an essential fatty acid - ᵧ-linolenic acid (GLA) - but also polyphenols which can be obtained from the biomass remaining after oil pressing. The aim of our studies was to evaluate the influence of a polyphenol extract from defatted seeds of evening primrose on human colorectal adenocarcinoma Caco-2 cell proliferation and matrix metalloproteinases (MMPs) synthesis and activity. To assess the effect of evening primrose extract on Caco-2 cell proliferation, crystal violet staining and sulforhodamine B (SRB) assays were used whereas mRNA expression and activity of MMPs were evaluated by RT-PCR and gelatin zymography. The results revealed that the examined polyphenol extract had little influence on Caco-2 proliferation, but effectively in a time- and dose-dependent manner inhibited MMP-1, MMP-7, MMP-9 and MMP-14 mRNA synthesis induced by TNF-α and TPA. Additionally, zymographic analysis revealed that after 24 h, the polyphenol extract at a concentration of 50 μmol/L GAE caused a 10-fold reduction in MMP-9 synthesis. Moreover, this extract might be a potent inhibitor of MMP activity. The results showed that polyphenol extract from evening primrose inhibited PBMC-derived MMP-2 and MMP-9 enzymatic activity in dose-dependent manner. The obtained results indicate that the polyphenol extract from evening primrose seeds could be an inhibitor of proteases involved in tumor progression and metastasis

    Magnetic microscopy of topologically protected homochiral domain walls in an ultrathin perpendicularly magnetized Co film

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    Next-generation concepts for solid-state memory devices are based on current-driven domain wall propagation, where the wall velocity governs the device performance. It has been shown that the domain wall velocity and the direction of travel is controlled by the nature of the wall and its chirality. This chirality is attributed to effects emerging from the lack of inversion symmetry at the interface between a ferromagnet and a heavy metal, leading to an interfacial Dzyaloshinskii-Moriya interaction that can control the shape and chirality of the magnetic domain wall. Here we present direct imaging of domain walls in Pt/Co/AlOx_x films using Lorentz transmission electron microscopy, demonstrating the presence of homochiral, and thus topologically protected, N\'{e}el walls. Such domain walls are good candidates for dense data storage, bringing the bit size down close to the limit of the domain wall width

    Velocity enhancement by synchronization of magnetic domain walls

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    Magnetic domain walls are objects whose dynamics is inseparably connected to their structure. In this work we investigate magnetic bilayers, which are engineered such that a coupled pair of domain walls, one in each layer, is stabilized by a cooperation of Dzyaloshinskii-Moriya interaction and flux-closing mechanism. The dipolar field mediating the interaction between the two domain walls, links not only their position but also their structure. We show that this link has a direct impact on their magnetic field induced dynamics. We demonstrate that in such a system the coupling leads to an increased domain wall velocity with respect to single domain walls. Since the domain wall dynamics is observed in a precessional regime, the dynamics involves the synchronization between the two walls, to preserve the flux closure during motion. Properties of these coupled oscillating walls can be tuned by an additional in-plane magnetic field enabling a rich variety of states, from perfect synchronization to complete detuning

    Skyrmion morphology in ultrathin magnetic films

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    Nitrogen-vacancy magnetic microscopy is employed in quenching mode as a non-invasive, high resolution tool to investigate the morphology of isolated skyrmions in ultrathin magnetic films. The skyrmion size and shape are found to be strongly affected by local pinning effects and magnetic field history. Micromagnetic simulations including static disorder, based on a physical model of grain-to-grain thickness variations, reproduce all experimental observations and reveal the key role of disorder and magnetic history in the stabilization of skyrmions in ultrathin magnetic films. This work opens the way to an in-depth understanding of skyrmion dynamics in real, disordered media.Comment: 9 pages, 8 figures, including supplementary information
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