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Compressed sensing in magnetic resonance perfusion imaging.
Mangová, Marie ; Veselý, Vítězslav (referee) ; Rajmic, Pavel (advisor)
Magnetic resonance perfusion imaging is a today's very promising method for medicine diagnosis. This thesis deals with a sparse representation of signals, low-rank matrix recovery and compressed sensing, which allows overcoming present physical limitations of magnetic resonance perfusion imaging. Several models for reconstruction of measured perfusion data is introduced and numerical methods for their software implementation, which is an important part of the thesis, is mentioned. Proposed models are verified on simulated and real perfusion data from magnetic resonance.
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Online Games Chat Reconstruction
Beran, Pavel ; Pluskal, Jan (referee) ; Veselý, Vladimír (advisor)
We live in modern times. We are surrounded by many different forms of information technologies. We watch movies, surf on the internet, play videogames and overall do lots of action that leave a trace in the cyberworld. This thesis investigates the possibility of using(playing) videogames as a decoy for getting involved in criminal activities, specifically MMORPG games, different ways of capturing and reproducing player´s chat communication. It also introduces a way to implement chat reconstruction module into Netfox.framework and other ways of communication visualisation.
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Microsoft Office Password Recovery Using GPU
Zobal, Lukáš ; Veselý, Vladimír (referee) ; Hranický, Radek (advisor)
This thesis describes the password recovery of Microsoft Office documents by expanding an existing tool Wrathion. The thesis explains the issue of digital document protection, modern encryption and hashing algorithms and rudiments of OpenCL standard. Next, the analysis of structure of MS Word, MS Excel and MS PowerPoint documents is performed, including all the versions since 1997. Using this knowledge, we create a draft and an implementation of improved DOC module for newer versions of the encryption, as well as a draft and an implementation of brand new modules for XLS and PPT formats and their newer variants DOCX, XLSX and PPTX. After that, we measure performance of the new modules and compare it with other competing password recovery tools.
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User and Device Metadata Collection from the Darkweb
Gula, Ján ; Matoušek, Petr (referee) ; Veselý, Vladimír (advisor)
This bachelor's thesis solves the problem of anonymization on the Internet, that is widely used for dealing with illegal substances. This problem drives law enforcement agencies to be interested in web pages that represent markets with forbidden content which are hidden behind anonymity networks. My goal is to focus on the biggest markets with such content and to gather as much information as possible about subjects that posture on similar types of web pages either as sellers or as buyers. I have resolved the given problem by choosing the most impactful markets according to the number of users signed in. I have become one of the users and applied algorithms for data scraping to get information from web pages into a structured form that is more suitable for a deeper analysis. The results of this thesis will help law enforcement agencies with the analysis of metadata of users that commit illegal activities as they will not have to manually search through the illegal markets, and they will have all available data summed up in a structured form in a database. Unifying data into a structured form will help speeding up the investigation and address the biggest drug sellers.
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Optimized Video Streaming on Android Platform
Spurný, František ; Ščuglík, František (referee) ; Veselý, Vladimír (advisor)
The subject of this term project is the analysis and description of possibilities in video streaming optimization, and the design of a client/server application to implement optimized video streaming in practice. The client side of the application is realized with a mobileapplication for the Android platform, which in addition to video streaming implements the functionality of a file manager over directories and files saved in the cloud.
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Modelling of L2 Loop-Preventing Protocols
Hrnčiřík, Matej ; Grégr, Matěj (referee) ; Veselý, Vladimír (advisor)
This thesis informs about currently used technologies, which provide loop protection on data link layer of computer networks. It clarifies issues of Ethernet networks. Chosen protocols are then closely described. There are presented advantages and disadvantages of chosen protocols and they are compared to other technologies. Practical section describes the initial implementation of IS-IS in OMNeT++ environment, which serves as the basic building block of TRILL protocol. An important issue is to verify correctness of implementation.
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Analysis of fracture of quasibrittle materials using numerical modelling and acoustic/electromagnetic emission
Vodák, Ondřej ; Vořechovský, Miroslav (referee) ; Veselý, Václav (advisor)
This master thesis gives overview of non-destructive tests of concrete and provides detailed information concerning the acoustic and electromagnetic emission during monitoring of concrete failure. Conducted loading tests of plain concrete specimens are described in the thesis together with the performed numerical simulations of these tests in the software ATENA. The simulation results of concrete failure are analysed in detail and compared with the experimental results recording failure processes with the help of acoustic and electromagnetic emission. The majority of simulation results in software ATENA 3D show good agreement with the recorded data.
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Restoration of degraded audiosignals using sparse representations
Mokrý, Ondřej ; Veselý, Vítězslav (referee) ; Rajmic, Pavel (advisor)
This bachelor thesis is focused on the problem of inpainting a segment of missing samples in an audiosignal. The signal is represented as sparse vector using discrete Gabor transform. The problem of inpainting missing samples while preserving the sparsity of the representation is formulated as an optimisation task, which is then solved using Douglas-Rachford algorithm. In contrast with the state-of-the-art approaches, the algorithm is extended by proposing method for compensating the energy decrease which occurs in the restored signal.
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Multicast Distribution Trees Modelling in OMNeT++
Malik, Adam ; Ryšavý, Ondřej (referee) ; Veselý, Vladimír (advisor)
Support of multicast routing and its implementation is one of the main goals in nowadays computer networks. Adapting new technology could be often challenging and connected with difficulties. For this reason its better to try it in some simulating enviroment and implement it only after successful results of tests and simulations. The aim of this diploma thesis is to familiarize the reader with the multicast routing, describe the possibilities of network testing in OMNeT++ and come up with new multicast routing framework for this discrete simulation tool.
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