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Segmentation of Electrocardiographic Signals Using Deep Learning Methods
Hejč, Jakub ; Černý, Martin (referee) ; Halámek, Josef (referee) ; Kolářová, Jana (advisor)
The thesis deals with deep learning methods for the segmentation of surface and intracardiac electrocardiographic recording with focus on atrial activity. The theoretical part introduces current segmentation aproaches of electrocardiographic signals. Issues related to the development of deep learning models in context of standard ECG databases were also discussed. We proposed a pipeling for processing multimodal electrophysiology data from interventional procedures in order to build reliable training datasets. A deep model for segmentation of intracardiac recordings based on a modified residual architecture was proposed. A series of experiments was conducted to evaluate the effect of both model and dataset properties on segmentation quality. The annotation methodology of recordings with atrial fibrillation proved to be a crucial factor. Properties of loss function and type of data augmentation were revealed as secondary important parameters. A novel P wave segmentation method for incomplete references was proposed in the thesis. The approach was inspired by the deep contrast learning. It was modified to distinguish local segments of signals at different levels of abstraction of the extracted feature maps. Results were analyzed using standard quality metrics and post-hoc visual analysis. In some cases, a statistical comparison of experiments for different settings was performed. The results of the work showed that it is possible to use intracardiac signals for embedding a vector representation of local atrial activation into deep models.
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Utilization of light emitting diode lighting
Podola, David ; Černý, Michal (referee) ; Paloušek, David (advisor)
This bachelor thesis deals with problems of illumination by LED diodes. Basic concepts of lighting technology are defined in the first part. The second part is dealing with the construction of body LED diodes and explains the principle of white light formation to LED. Introduces problems of cooling. Gives an overview of the available power sources for LEDs. Provides an overview of how to control lighting by using motion sensors and presence sensors. Will be made basic economic balance sheet, which will evaluate the advantages of using LED sources. Attachments provide the LED catalogs of manufacturers, accessories for LED and comment on other sources of information.
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Hybrid Blends of Recycled Plastics
Černý, Miroslav ; Lehocký, Marián (referee) ; Balgová,, Vendula (referee) ; Jančář, Josef (advisor)
Work describes the relationship between structure and mechanical properties in case of hybrid mixtures. They are composed from polyurethane matrices (eventually polyurethane-urea or polyurethane-inorganic filler mixtures), different rubber fractions as filler and eventually reinforcement made from PET monofilaments. Mechanical behaviour was studied by tensile testing. Studied mechanical properties include tensile modulus, ultimate strength and strain and also specific energy need neccessary for ultimate strength achievement. Prepared materials are naturally porous. Therefore their mechanical behaviour has to be described generally for porous composites. The porosity occurence means, that it is difficult to describe them by models valid for mechanical behaviour (mainly elastic modulus) of nonporous composites. Models are also based on idealized structures on microscopic level. In case of porous composites, it is very difficult to create any idealized structure. The structure is changed with modifications of composition (change of components or their rates). These conditions have lead to utilizing of different approach how to describe the relationship between structure and mentioned mechanical properties. The chosen approach comes from knewledge about structural parametres coming from porosity. Structural parameters describe the structure on macroscopic level. They include interspace volume (volume lying between filler particles), interspace filling (how the matrix fills the interspace volume) and matrix volume fraction. Proposed parameters are used in relations, where they are fitted by exponents to interlay values of chosen mechanical properties for composites containing discrete matrix and filler. Found exponents are then described by properties of matrices to obtain relations describing properties of filled porous materials. Very similar approach was chosen for description in the case of reinforced composites. Proposed relation are potentially valid for materials containing binding matrix, infinity count of fillers and one kind of reinforcement.
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Desing and Production of Plastic Adapter to Floor Nozzle
Černý, Martin ; Sliwková, Petra (referee) ; Sedlák, Josef (advisor)
This work deals with the design and manufacture of prototypes of plastic reduction to the floor nozzle. Individual shapes and dimensions of the reduction are designed and constructed in 3D parametric software Autodesk Inventor. Models of reduction are produced using an additive method of Fused Deposition Modeling utilizing a 3D printer uPrint. Work is completed techno-economic evaluation with the subsequent analysis and overall evaluation of the applied technology.
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Eluding and Evasion of IDS Systems
Černý, Marek ; Tobola, Jiří (referee) ; Žádník, Martin (advisor)
This paper analyzes network security devices called intrusion detection (ID) systems. In order to point out possible flaws, especially ID systems using signature analysis are examined. Based on this, methods to exploit possible vulnerabilities of these systems were designed. These methods were implemented into a simple program for ID systems efficiency evaluation. It can be used in a way entirely independent of particular network attack used in the test.
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FIRST PRINCIPLES ANALYSIS OF MECHANICAL STABILITY OF SOLID CRYSTALS
Řehák, Petr ; Buršík, Jiří (referee) ; Šob, Mojmír (referee) ; Černý, Miroslav (advisor)
The aim of the author’s research in the period of his PhD study was the analysis of mechanical stability of cubic crystals under external loading. This work demonstrates several methods used for a study of mechanical stability of fcc crystals (C, Al, Ir, Pt, Au) during isotropic (hydrostatic) tensile loading. Ab initio methods were used for this purpose. Studied crystals were subjected to simulated isotropic tensile deformation and an analysis of elastic stability was performed. This analysis shows that first elastic instability in Al, Pt and Au crystals corresponds to vanishing of the trigonal shear modulus and diamond, Ir remains stable up to the state of maximum isotropic stress. According to the calculated band structure diamond crystal preserves his insulating character up to the onset of instability. Consequently, phonon spectra of all crystals were calculated using the linear response method and their dynamic stability was assessed. Obtained results reveal soft phonon modes in Al, Pt and Ir before an occurrence of elastic instability. Selected short-wavelength instabilities are confirmed using models of microscopic deformation and also using dispersion curves obtained by a supercell method. The observed instabilities lower critical strains related to the volumetric instability up to 40 % whereas the reduction of critical stress is by 20 % at the most.
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Development of the Control program for Total station for athletics field Events
Papež, Jakub ; Černý, Martin (referee) ; Kuruc, Michal (advisor)
In this Bachelor’s thesis is created system MERADIS, which controls a total station, measure angles and lengths and processes the measured values. The system is designed for use in measuring performance in athletic field events. In the introductory part of this work are presented athletic field events and their measurement. Next part is devoted analyzes of measurement accuracy and measurement development program. The last part briefly describes the individual components of the system MERADIS.
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Design of Data Acquisition Equipment IMC Fastening System in the Car
Černý, Martin ; Jeník, Radomír (referee) ; Ramík, Pavel (advisor)
Devices for measuring the dynamic load and vibration of certain parts of the bodywork or parts of other parts of the vehicle are made using accelerometers and measuring instruments IMC. It must be simply installed into the interior of the vehicle so that it is not necessary to remove any parts of the interior and to avoid damage to all parts of the interior. The preparation must also withstand the considerable dynamic load generated by the harder operation tests.
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QUANTUM MECHANICAL STUDY OF PHASE STABILITY IN METALLIC SYSTEMS
Káňa, Tomáš ; Vřešťál, Jan (referee) ; Paidar,, Václav (referee) ; Černý, Miroslav (referee) ; Šob, Mojmír (advisor)
This work presents a theoretical study of stability of phases in selected metallic systems. We propose a model of structural transformations in transition metal disilicides MoSi2, CrSi2, VSi2 and TiSi2 and in Pd thin films grown on cubic substrates W(001) and Nb(001). The obtained results yield the total energy proles for the structural transformations studied, the activation energies needed for each individual transformation and an estimate of the temperature at which the structure can transform. The total energies are calculated by full-potential linearized augmented plane waves (FLAPW) method incorporated in the WIEN2k code. Both generalized gradient approximation (GGA) and local density approximation (LDA) are employed for the exchange-correlation term. It turns out that temperatures corresponding to the activation energies of structural transformations in transition metal disilicides exceed their melting temperatures. Comparing the resulting total energy proles to those obtained by the semiempirical Bond Order interatomic potentials (BOP) substantially helps to adjust the fitting parameters of the BOPs. The estimated temperature of 168 K needed to transform the hcp structure of an innite Pd crystal into the dhcp structure explains the behavior of the Pd thin lm on W(001) and Nb(001) substrates. Pd lms deposited on W(001) substrate and thicker than about 100 monolayers undergo this transformation already at room temperature. Thinner lms need to be annealed at 400 K rst, due to their stronger interaction with the substrate. The difference between the computed result and a real temperature at which the hcp Pd lm transforms its structure to the dhcp can be explained by both the interaction between the lm and the substrate and by the inuence of the domain topology of the lm. Analyzing different models of transformation of the initial hcp Pd structure to the ground state fcc structure, we identied the optimum model that respects the domain topology of the Pd lm.
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Solution of modernization technology of part air-pump
Černý, Michal ; Dvořák, Jaromír (referee) ; Kalivoda, Milan (advisor)
The subject of this thesis is modernization of manufacturing process of air-pump component in a specific company. The work is focused on designing a new variant of the manufacturing process for mass production of the given component. The introduction evaluates the technology of product manufacture and describes the existing technologies of performed prototype production. The second chapter introduces a machine-tool, which will play the existing role of production, which will streamline the productivity of work, reduce the risk of human error and improve the quality of manufacturing accuracy. Further new tools are selected and a new production technology is designed. In conclusion, machine times and an overall design of production are evaluated.
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