National Repository of Grey Literature 29 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Image Edge Detection Using Convex Optimisation
Novosadová, Michaela ; Róka, Rastislav (referee) ; Dostál, Otto (referee) ; Rajmic, Pavel (advisor)
Detekce hran v obraze je jednou z nejdůležitějších technik v oblasti digitálního zpracování obrazu. Bývá používána, mimo jiné, jako první krok segmentace obrazu. I proto stále zůstává v oblasti zájmu vědců, kteří se snaží vyvíjet stále lepší detekční přístupy. Hlavním cílem této práce je nalezení vhodné metody detekce hran v obraze pomocí konvexní optimalizace. Navržená metoda je založená na řídkém modelování, a její hlavní část je formulována jako konvexní optimalizační problém, který je řešen pomocí proximálních algoritmů. Pro definici optimalizačního problému se předpokládá, že signál může být modelován jako přeparametrizovaný po částech polynomiální signál, který se skládá z disjunktních segmentů. Počet těchto segmentů je výrazně menší než je počet vzorků signálu, což vybízí k použití řídkosti. Návrh vhodného optimalizačního problému nejdříve probíhá na jednorozměrných signálech, jelikož implementace a porovnání jednotlivých algoritmů je pro jednorozměrné signály výrazně jednodušší a časově méně náročná, než pro dvojrozměrné. První část práce se věnuje představení základní teorie z oblasti zpracování signálu, řídkosti, konvexní optimalizace a proximálních algoritmů, a dále prezentuje průřez používanými metodami pro hranovou detekci v obraze. Druhá část práce se zaměřuje na návrh a následné vyhodnocení jednotlivých optimalizačních problémů pro segmentaci jednorozměrných syntetických signálů, které jsou poškozeny šumem. Vyhodnocení je provedeno jak z pohledu přesnosti detekce skoků tak i odšumění. Poslední část práce je věnována rozšíření nejlépe fungujícího přístupu k detekci skoků v jednorozměrném signálu pro použití na detekci hran v obraze. V této části je navržený přístup testován na standardizovaném datasetu obrázků, který obsahuje manuálně označené hrany od několika subjektů. Výsledky navržené metody jsou vyhodnoceny pomocí precision-recall křivek a jejich maximálního F skóre a následně porovnány s ostatními metodami hranové detekce.
Legal Aspects of Fighting Cybercrime
Dostál, Otto ; Vlček,, Martin (referee) ; Šárek, Milan (referee) ; Hajný, Jan (advisor)
The thesis deals with the topic of computer crime. Foremost, it demonstrates on an example of the operation of a medical image information processing system some selected aspects of this issue. It shows that it is always necessary to monitor the current state of the technical knowledge at the time, but also the need of addressing the issue within the corresponding legal limits. The thesis presents criminal law reality as a complex system. The links between different parts of the system are examined, and possible shortcomings are considered. The legal instruments and legal limits of the procedures that can be used against cybercrime are evaluated. The thesis focuses especially on the issue of obtaining evidence under the Czech Criminal Procedure Code. It presents a proposal on how to understand individual procedural legal institutes and for what purposes and how to use them. Consequently it suggests legal procedures for specific selected practical situations.
Advanced Security Methods of Medical Image
Roček, Aleš ; Šimák, Boris (referee) ; Molnár, Karol (referee) ; Dostál, Otto (advisor)
Medical institutions adapt digital based archiving of patients records images to fulfil its advantages like availability, easy sharing, high resolution etc. Digital form of records brings apart from advantages also disadvantages at security risks. It is easier attacking, stealing, using without authorization etc. This thesiss deals with this security issues, describes the needs and approaches to security, explains the reasons for deployment of watermarking. It names three main methods of medical image watermarking and compares their plus and cons: zero, reversible and watermarking in Region Of Non Interest (RONI). New method of Zero-reversible-RONI watermarking, that combine advantages of described methods, is proposed. For practical tests of properities of proposed method was used huge database of medical images. Application of the proposed method on this database delivers very promising results. Practical results discussion and comparison with other medical imaging watermarkikng methods are at the end of this thesis.
Authentication Using Lightweight Cryptography
Člupek, Vlastimil ; Uchytil, Stanislav (referee) ; Dostál, Otto (referee) ; Zeman, Václav (advisor)
The dissertation thesis deals with cryptographic protocols for secure authentication of communicating parties, which are intended primarily for low-cost devices used in Internet of Things. Low-cost devices represent computationally, memory and power constrained devices. The thesis focuses mainly on the possibilities of using mathematically undemanding cryptographic resorces for ensuring integrity of transmitted dat, authenticity of and secured transmission of data on low-cost devices. The main goals of the thesis focus on the design of new advanced cryptographic protocols for ensuring integrity of transmitted data, authenticity, confidentiality of transmitted data between low-cost devices and authenticity with non-repudiation of done events. The thesis describes proposal of three authentication protocols, one unilateral authentication protocol and two mutual authentication protocols. The thesis also describes proposals of two protocols for secured transmission of data between two devices, one protocol without a proof of receipt data and one protocol with proof of receipt data. In this thesis is also performed a security analysis and a discussion to proposed protocols.
Measurement of the optical fiber
Procházka, Jakub ; Dostál, Otto (referee) ; Filka, Miloslav (advisor)
This bachelor's thesis deals with measurement methods of optical fiber. In the thesis, methods for measurements of attenuation, chromatical dispersion, and polarization mode dispersion are discussed. The thesis also deals with methods for measurement of attenuation of passive components and their reflections loss. Also discussed are parameters of selected types of optical fibers, basic findings about optical transmission and principle of wave multiplexing. The practical portion of the thesis deals with measurement of a new optical polygon in the Academic Optical Network in Brno.
Polymer optical fibers - POF
Mitrič, Martin ; Dostál, Otto (referee) ; Filka, Miloslav (advisor)
Polymer Optical Fibers - POF in recent years reach into values attenuation about 10 dB • km-1. This is the value that makes these fibers applicable for data transmissions over short distances. Between the great advantages of these fibers include simple installation and easy preparation of the connectors. The aim of of this work is to introduce the issue of the POF fiber. The work begins with becoming familiar with different types of fiber POF, their basic characteristics and differences. It also deals with methods of linking these different types of fibers and connectors designed for these fibers. Another chapter focuses on the possible use of these fibers in FTTx networks and their future. Work continues overview of the types of optical access network and transmission design polygon using POF fibers for laboratory purposes. The final part presents the results of measurements of fundamental properties of the POF fiber.
Optical network FTTH
Horníček, Lukáš ; Dostál, Otto (referee) ; Filka, Miloslav (advisor)
The bachelor's thesis „Optical Network FTTH“ is a theoretical and practical analysis of problems of optical access networks with respect to current and prospective trends in the construction and operation of these networks. For the clearness of thesis done divided into 6 chapters. The first five chapters deal with the optical access networks at a theoretical level with a touch of practical knowledge in the academic analysis. The first chapter deals with general concepts networks FTTH and defines the reasons for their occurrence. The second thematic chapter specifies an individual topology implemented in optical networks FTTH, their advantages and disadvantages with respect to transfer capacity and the economic-competitive potential of the network. It is defined by a principled division of optical networks in the active and passive with the definition of network architectures, communication models and protocols. The individual architectures are evaluated for suitability in the deployment of networks FTTH. The third and fourth thematic chapters inform readers with the passive and active access network FTTH infrastructure. Passive infrastructure examines the method of construction used in the past decades and the latest technology microtubing that this networks concept prevailed. The fifth thematic chapter provides Triple Play services and reasons for using these services just for FTTH optical networks. The sixth chapter is a crucial element in this thesis. Results and knowledge acquired in previous chapters is applied to real network model. It is defined by imaginary the village "Fektákov" for which they are created by three case studies covering technical and economic documentation for the realization of a real access FTTH network. This allows compare the modern ways of realization network infrastructure, including central office and subscriber terminal equipment. The results of these three case studies, conclusions are drawn that highlight the strengths and weaknesses of these architectures and also suggest the quality and reliability of these networks and the expected future prospects of development. Conclusion of the thesis is an evaluation of all evidence obtained in this work reflects the author's view on current and expected future developments in optical access networks leading its optical fiber to homes or apartments of all households.
Analysis of Speech Signals for the Purpose of Neurological Disorders IT Diagnosis
Mekyska, Jiří ; Dostál, Otto (referee) ; Přibilová, Anna (referee) ; Smékal, Zdeněk (advisor)
This work deals with a design of hypokinetic dysarthria analysis system. Hypokinetic dysarthria is a speech motor dysfunction that is present in approx. 90 % of patients with Parkinson’s disease. The work is mainly focused on parameterization techniques that can be used to diagnose or monitor this disease as well as estimate its progress. Next, features that significantly correlate with subjective tests are found. These features can be used to estimate scores of different scales like Unified Parkinson’s Disease Rating Scale (UPDRS) or Mini–Mental State Examination (MMSE). A protocol of dysarthric speech acquisition is introduced in this work too. In combination with acoustic analysis it can be used to estimate a grade of hypokinetic dysarthria in fields of faciokinesis, phonorespiration and phonetics (correlation with 3F test). Regarding the parameterization, features based on modulation spectrum, inferior colliculus coefficients, bicepstrum, approximate and sample entropy, empirical mode decomposition and singular points are originally introduced in this work. All the designed techniques are integrated into the system concept in way that it can be implemented in a hospital and used for a research on Parkinson’s disease or its evaluation.
Challenges in Optimal Bandwidth for Medical Image Transfer
Schindler, Vladimír ; Šimák, Boris (referee) ; Šárek, Milan (referee) ; Dostál, Otto (advisor)
This dissertation thesis is focused on the optimization of bandwidth parameters for the transport of medical image data between medical devices and remote data storage. As real and fully functional structure, which will be analyzed in this work. It was selected system MeDiMed (Metropolitan Digital Imaging System in Medicine). The thesis examines the operation of the small health organizations and their modalities, which use this system for remote data archiving. Traffic analysis is then statistically processed. The thesis also deals with the analysis of increasing the security during accessing health system, and assesses its impact on transmitted data. The effect of setting the transmission parameters and the most widely used types of ciphers on the transfer speed is also compared.
Keyword Detection in Speech Data
Pfeifer, Václav ; Makáň, Florian (referee) ; Dostál, Otto (referee) ; Balík, Miroslav (advisor)
Speech processing systems have been developed for many years but the integration into devices had started with the deployment of the modern powerful computational systems. This dissertation thesis deals with development of the keyword detection system in speech data. The proposed detection system is based on the Large Margin and Kernel methods and the key part of the system is phoneme classifier. Two hierarchical frame-based classifiers have been proposed -- linear and non-linear. An efficient training algorithm for each of the proposed classifier have been introduced. Simultaneously, classifier based on the Gaussian Mixture Models with the implementation of the hierarchical structure have been proposed. An important part of the detection system is feature extraction and therefor all algorithms were evaluated on the current most common feature techniques. A part of the thesis technical solution was implementation of the keyword detection system in MATLAB and design of the hierarchical phoneme structure for Czech language. All of the proposed algorithms were evaluated for Czech and English language over the DBRS and TIMIT speech corpus.

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11 Dostál, Ondřej
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