Deep multiple-instance learning for detecting multiple myeloma in CT scans of large bones

S nástupem moderních algoritmů strojového učení vzrostla popularita tématu automatické interpretace výstupů zobrazovacích metod v medicíně pomocí počítačů. Konvoluční neuronové sítě v současné době excelují v mnoha oblastech strojového vidění včetně rozpoznávání obrazu. V této diplomové práci zkoumáme možnosti využití konvolučních sítí jako diagnostického nástroje pro detekci abnormalit v CT snímcích stehenních kostí. Zaměřujeme se na diagnózu mnohočetného myelomu pro nějž jsou charakteristické viditelné léze v kostní dřeni, které lze pozorovat při vyšetření pomocí počítačové tomografie. Bylo otestováno několik různých přístupů včetně učení z více instancí. Náš klasifikátor podává spolehlivý výkon v experimentech s plně supervizovaným učením, vykazuje ovšem zásadní neschopnost konvergence při učení z více instancí. Předpokládáme, že náš navrhovaný neuronový model potřebuje ke konvergenci silnější chybovou odezvu a na toto téma navrhujeme budoucí možná vylepšení.The employment of computer aided diagnosis (CAD) systems for interpretation of medical images has become an increasingly popular topic with the arrival of modern machine learning algorithms. Convolutional neural networks perform exceptionally well nowadays in various pattern recognition tasks including image classification. In this thesis we examine the capabilities of a convolutional neural network binary classifier as a CAD system for detection of abnormalities in CT images of femurs. We focus on the diagnosis of multiple myeloma characterized by symptomatic bone marrow lesions commonly observable through computer tomography screening. Different approaches to the problem including multiple instance learning (MIL) were tested. The classifier showed a solid performance in our fully supervised experimental setting, it however exhibits a serious inability to learn from multiple instances. We conclude that the proposed neural model needs a stronger error signal in order to converge in the standard MIL setting and suggest potential improvements for further work in this area

Tool for Processing and Presentation of Car Sales Statistics

Tato bakalářská práce mapuje aktuální možnosti získávání informací o automobilech a prodejích automobilů s ohledem na jejich další zpracování pro vizualizaci v podobě grafů a interaktivních tabulek. Jejím hlavním výstupem je automatizovaný nástroj pro získávání dat a znovupoužitelná komponenta pro vizualizaci těchto dat. Postupně je čtenář seznámen s aktuálními zdroji těchto dat a možností jejich vizualizace pomocí rozšiřujících volně dostupných knihoven. Součástí práce je analýza zdrojů dat, specifikace zadání, analýza nástroje, návrh komponenty a její implementace. Na závěr je kapitola s úvahou o možném vylepšení komponenty. Nástroj a komponenta jsou implementovány pomocí jazyka PHP, JS a jejich rozšířeními.This bachelor thesis maps actual posibilities of achievieng informations about cars and car sales regard to their firther processing for visualization with graphs and interactive tables. It's main output is automatic tool to obtain data and reusable component for visualization. The reader is acquainted with the source of this data and posibility of their visualization using freely available libraries. Next part of thesis is data analysis, specifications, tool analysis, design and implementation. Finaly considering possible component improvements. The tool and component are implemented using PHP, JS, HTML, CSS and their extensions.460 - Katedra informatikyvelmi dobř

Comparing the effect of endurance and resistance training on resting metabolic rate in a group of men with a sedentary lifestyle

Study examined the effects of aerobic and anaerobic exercise on resting metabolic rate (RMR) and body composition and compared changes in these parameters in group of men (n=17), aged 17-36, with sedentary lifestyle. During the initial measurements, the values of RMR, body composition and exercise test were obtained. In addition, five-day nutritional intake and record of physical activity were completed. After the initial measurements, subjects were randomly assigned in two training groups. Subjects in group EX1 (n=9) performed aerobic physical activity – endurance training (jogging and/or running), whereas subjects in group EX2 (n=8) performed anaerobic physical activity – resistance training. Physical activity was performed for 12 weeks, 3 times a week. The output measurements were obtained after 12 weeks of regular physical activity. Data of RMR were collected using the air analyzer Metalyzer Cortex 3B in the Laboratory of Sports Medicine, Faculty of Sports Studies in Brno. For body composition, method of bioelectrical impedance analysis has been used. RMR increased significantly from pre- to postraining for EX1 (2045,8 ± 207,5 to 2168,8 ± 217,7 kcal.d-1) as well as for EX2 (1992 ± 164,4 to 2340 ± 321,3 kcal.d-1). Body fat for EX1 was significantly reduced (21,2 ± 6,4 to 18,7 ± 6,8 %) compared with EX2 (22,4 ± 6,2 to 20,6 ± 7,6 %). Measured data indicate more significant changes by subjects from EX1 group (endurance training). This study is a part of research for the dissertation of one of the authors and was financially supported from projects of specific research MUNI/A/0987/2011 and MUNI/A/0803/2012

Plasmonic properties of individual gallium nanoparticles

Gallium is a plasmonic material offering ultraviolet to near-infrared tunability, facile and scalable preparation, and good stability of nanoparticles. In our contribution, we experimentally demonstrate the link between the shape and size of individual gallium nanoparticles and their optical properties. To this end, we utilize scanning transmission electron microscopy combined with electron energy loss spectroscopy. Lens-shaped gallium nanoparticles with a diameter between 10 nm and 200 nm were grown directly on a silicon nitride membrane using an in-house developed effusion cell operated at ultra-high vacuum conditions. We have experimentally proved that they support localized surface plasmon resonances and their dipole mode can be tuned through their size from ultraviolet to near-infrared spectral region. The measurements are supported by numerical simulations using realistic particle shapes and sizes. Our results open the way for future applications of gallium nanoparticles such as hyperspectral absorption of sunlight in energy harvesting or plasmon-enhanced luminescence of ultraviolet emitters

Density functional study of gallium clusters on graphene: electronic doping and diffusion

Motivated by experimental results on transport properties of graphene covered by gallium atoms, the density functional theory study of clustering of gallium atoms on graphene (up to a size of 8 atoms) is presented. The paper explains a rapid initial increase of graphene electron doping by individual Ga atoms with Ga coverage, which is continually reduced to zero, when bigger multiple-atom clusters have been formed. According to density functional theory calculations with and without the van der Waals correction, gallium atoms start to form a three-dimensional cluster from five and three atoms, respectively. The results also explain an easy diffusion of Ga atoms while forming clusters caused by a small diffusion barrier of 0.11 eV. Moreover, the calculations show this barrier can be additionally reduced by the application of an external electric field, which was simulated by the ionization of graphene. This effect offers a unique possibility to control the cluster size in experiments only by applying a gate-voltage to the graphene in a field-effect transistor geometry and thereby without growth temperature assistance.Grant Agency of the Czech RepublicGrant Agency of the Czech Republic [17-21413S]; Ministry of Education, Youth and Sports from the Large Infrastructures for Research, Experimental Development and Innovations project 'IT4 Innovations National Super-computing Center' [LM2015070

Mechanism and Suppression of Physisorbed-Water-Caused Hysteresis in Graphene FET Sensors

Hysteresis is a problem in field-effect transistors (FETs) often caused by defects and charge traps inside a gate isolating (e.g., SiO2) layer. This work shows that graphene-based FETs also exhibit hysteresis due to water physisorbed on top of graphene determined by the relative humidity level, which naturally happens in biosensors and ambient operating sensors. The hysteresis effect is explained by trapping of electrons by physisorbed water, and it is shown that this hysteresis can be suppressed using short pulses of alternating gate voltages.Grant Agency of the Czech RepublicGrant Agency of the Czech Republic [17-21413S]; H2020 Twinning Programme (Project SINNCE) [810626]; MEYS CR [LQ1601 CEITEC 2020, LM2015041

Correlative Raman imaging and scanning electron microscopy: The role of single Ga islands in surface-enhanced Raman spectroscopy of graphene

Surface-enhanced Raman spectroscopy (SERS) is a perspective nondestructive analytic technique enabling the detection of individual nanoobjects, even single molecules. In this paper, we have studied the morphology of Ga islands deposited on chemical vapor deposition graphene by ultrahigh vacuum evaporation and local optical response of this system by the correlative Raman imaging and scanning electron microscopy (RISE). Contrary to the previous papers, where only an integral Raman response from the whole ununiformed Ga nanoparticles (NPs) ensembles on graphene was investigated, the RISE technique has enabled us to detect graphene Raman peaks enhanced by single Ga islands and particularly to correlate the Raman signal with the shape and size of these single particles. In this way and by a support of numerical simulations, we have proved a plasmonic nature of the Raman signal enhancement related to localized surface plasmon resonances. It has been found that this enhancement is island-size-dependent and shows a maximum for medium-sized Ga islands. A reasonable agreement between the simulations of the plasmon enhancement of electric fields in the vicinity of Ga islands and the experimental intensities of corresponding Raman peaks proved the plasmonic origin of the observed effect known as SERS. © 2022 American Chemical Society.European Commission, EC: 71020004, 810626; Grantová Agentura České Republiky, GA ČRCzech Science FoundationGrant Agency of the Czech Republic [20-28573S]; European Commission (H2020-Twininning project)European Commission [810626.SINNCE, M-ERA NET HYSUCAP/TACR-TH71020004]; *BUT*.specific research [*FSI-S-20-648*5]; Ministry of Education, Youth and Sports of the Czech Republic (CzechNanoLab Research Infrastructure) [LM2018110

Magnetically guided soft robotic grippers

Soft robotic grippers based on magnetorheological elastomers are proposed. Rigid nonmagnetic skeleton of the gripper is encased by an elastomer with magnetic properties that exhibits soft-touch properties and reacts to external magnetic field. The basic concept of the grippers, their operation and first prototypes are presented together with the utilized magnetorheological material development and measurement of its mechanical and magnetic properties

Magnetic forces behind hyperelastic behavior of magnetorheological elastomers

A magnetic and nonlinear structural mechanic coupled problem is discussed concerning the behaviour of a magnetorheological elastomer. Material properties and hyperelastic character of the material were found by measurements. Based on the measurements and computations, a coupled mathematical model is proposed involving the Yeoh hyperelastic model

Magnetically Controlled Microfluidic Channels

A technological framework for entirely soft microfluidic channels controlled by an external magnetic is pro-posed. The crucial part of the channel is a multilayer structure compounded of a magnetorheological elastomer (MRE) and additional nonmagnetic layers that provide unique properties to the system. The proposed concept is studied by numerical simulations and experiments on laboratory prototypes