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Methods for the measurement of bit rates in data networks
Franc, Jan ; Martinásek, Zdeněk (referee) ; Zeman, Václav (advisor)
The target of this master's thesis were the known methods for testing the quality of transfer parameters of data networks. I have studied the RFC 2544 document to analyze these tests. From that information and by studying other existing web-based applications I was able to design a concept of my own application that will allow to measure basic quality parameters of transfers made through the Internet (the parameters: downstream, upstream, latency, variance of these and a traced route). My application doesn't require any modifications on the user's system. It's built on the server-based programming language PHP and uses the relational database engine MySQL to store measurement and user data. On the client side, it's assisted by the JavaScript scripting language. Both registered users and visitors are allowed to perform the listed measurements. Registered users are able to browse the history of their own benchmark results and also to send messages to others. There is an administrative account to oversee the operations. Another part of my thesis work is an application for Windows that performs the same measurements but does not use JavaScript.
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Host distance measurement using ICMP protocol in IP networks
Fojtová, Lucie ; Komosný, Dan (referee) ; Burget, Radim (advisor)
Current internet more and more often faces the problem of the right definition of distance between the single hosts. The knowledge of this quantity influences the areas of the optimal lay-out of overlay multicast networks, the right selection of peer-to-peer network participant, or the simple decision of the end user: which one of the nearest mirrors to use for downloading datas. The nearest one doesn't have to mean the nearest in geographical point of view - the distance on Internet is usually expressed by quantities as latency or bandwidth. All these examples have got the saving of bandwidth in common and therefore economical saving. The methods of host position prediction in networks work on the basis of measuring latency parameter. The tools for measuring of this parameter will be set up in this thesis and at the same time it will be shown how geographical distance and latency correspond with each other.
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Performing a Relay Attack on Mifare Smart Cards
Činčala, Martin ; Henzl, Martin (referee) ; Malčík, Dominik (advisor)
This thesis deals with performing a relay attack on MIFARE smartcards while using off-the-shelf readers only. These readers are not designed for such attacks therefore implementation of the attack that would succeed against every smartcard was not possible. Since various attacks on smartcards have already been implemented, I have focused on the latest and still insufficiently explored card MIFARE Ultralight C. Relay attack has been implemented with simplified emulation of 4-bytes long UID and successfully tested on MIFARE Ultralight C. With the use of other readers it should be possible to perform attack also on other cards like MIFARE Plus, Desfire and SmartMX. For the purpose of cloning MIFARE Classic open-source tools are introduced.
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Geolocation in Internet using latency measurements
Harth, Petr ; Balej, Jiří (referee) ; Komosný, Dan (advisor)
This diploma thesis is concerned with practical realization of CBG (Constraint-based Geolocation) algorithm, which is one of the IP (Internet Protocol) geolocation technique. IP geolocation determines the localization of a computer workstation location on the basis of on its IP address. The factors causing delays in data transfer are discussed first, followed by discussion of the issue of measuring these delays. The detailed explanation of IP geolocation follows where its contexts as well as the active geolocation techniques (techniques based on delay measurement mentioned above) are described. After that a brief description of PlanetLab experimental network, which was used for geolocation techniques measuring, is presented followed by a section explaining the creation of reference points and targets, which are another necessary prerequisite for practical realization of the method. Then the practical realization is explained in the form of CBGfinder program and its verification on the basis of artificial input data along with an actual example of IP geolocation of a point in the Internet are provided. Last but not least the measurement results of CBG algorithm are introduced, based on the analysis of Bestline parameters of one of the PlanetLab nodes measured in the period of one month, followed by a discussion of the inaccuracy of geological position and the computation speed. The cumulative distribution function as well as the kernel density estimation are also described. Final part of the thesis consists of discussion on measured results compared to results of other geological techniques results implemented by colleagues of the author of this diploma thesis. The results are compared on the basis of average inaccuracy of geological position estimations and its median, computation time, cumulative distribution function and kernel density estimation are also taken into regard.
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Semi-automated Design of High-performance Digital Circuits with Xilinx FPGAs
Houška, David ; Dvořák, Vojtěch (referee) ; Šťáva, Martin (advisor)
Tato diplomová práce se zabývá návrhem sekvenčních digitálních obvodů s ohledem na optimalizaci zpoždění. V práci je popsána problematika dvou technik, které jsou běžně používané při optimalizaci – stručně je popsána technika tzv. synchronizace registrů (angl. retiming), větší pozornost je však věnována technice tzv. zřetězení (angl. pipelining). V rámci praktické části byla vypracována forma abstrakce sekvenčních digitálních obvodů pomocí acyklických orientovaných grafů. Obvod je tak přenesen do roviny, ve které je jednodušší jej transformovat. Zároveň je představen nástroj pro polo-automatickou optimalizaci digitálních obvodů vyvíjených v prostředí Xilinx ISE Design Suite využitím techniky zřetězení.
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Geolocation of Internet nodes based on communication latency
Horák, Michael ; Balej, Jiří (referee) ; Komosný, Dan (advisor)
This thesis covers the topic of determination of geographical location of a host in internet network while utilizing measurement of the end to end delay and implementation of Constraint-Based Geolocation. Gradually I go through issue of the delay in computer networks and ways how to measure it. Next chapter describes a few ways to geolocate host in internet network with emphasis on the CBG method. Another chapter is dedicated to describing a way to project spherical coordinates to the two dimensional space, which has been used in implementation of geolocation method. Chapter about implementation builds upon the facts given in previous chapters while functions of the program written in the JAVA programing language are being explained. Two similar geolocation methods were implemented. By comparing the results gained by implementation, new method of geolocation is proposed and devised. It combines properities of both previous methods. There are results of the implemented methods and their comparation to the one of the source documents used in creation of this thesis in summary section.
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Virtualization of operating systems
Král, Jan ; Malina, Lukáš (referee) ; Komosný, Dan (advisor)
The diploma thesis ’Virtualization of Operating Systems’ deals with a general description of virtualization technology and briefly discusses its use cases and advantages. The thesis also mentions examples of different types of virtualization technologies and tools, including more thorough description of the two technologies used for measurement: Docker and KVM. The second part of this thesis descibes the preparation, installation and configuration of all the tools and services that are necessary for measurement of the influence of the aforementioned virtualization technologies on network services running on the virtual machines, including analysis and discussion of the resulting data. Moreover, a custom application for fully automated measurement of the parameters of network services was created, and is also described in this thesis. The conclusion of this thesis summarizes and discusses the achieved results and acknowledges the influence of virtualization on network services, where the Docker application containers, which are with their low overhead comparable to a "bare" system without any virtualization, managed to achieve much better performance results than the traditional virtual machines on KVM.
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Simulation of data transmission latency between nodes in IP networks
Balej, Jiří ; Molnár, Karol (referee) ; Komosný, Dan (advisor)
This master thesis is focused on the delays incurred in data transmitting over IP networks. The top of the paper is devoted to points, where delay is invoked and causes of the latency. For individual sources of delay are are described the parameters that affect the usual size of latency. The next section describes the types of networks and their typical delay. In the paper are also discussed tools for measuring delay and determining the number of intermediate devices. The thesis contains results of measurements delay time in the real network. For these results are listed conclusions about the delay for one intermediate device. There is also said general ratio of crow-fly distance and calculated distance. The last part deals the simulation of delay in the NS2 program. The results of thesis are scripts that shows the relation of delay and the number of switches, routers, and the length of the path.
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Measurement of communication latency in IP networks
Bednář, Vít ; Vrba, Kamil (referee) ; Komosný, Dan (advisor)
Semestral thesis is focused on measurement of communication delay in networks. There is described creation of individual kinds of delay during the transfer in networks. Tools for measurement of delay are described and web pages are designed and made too. There is measured delay on choose 27 IP address with help of this page.
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Architectural visualization in virtual reality
Hložanka, Filip ; Rujbrová, Šárka (referee) ; Reich, Pavel (advisor)
Tato práce se zaměřuje na nynější podobu virtuální reality a její využití v průmyslovém designu a architektuře. Je rozdělená do dvou částí. V první částí je popsána historie virtuální reality včetně fází vývoje a nejpopulárnějších produktů. Dále jsou v ní porovnány současné produkty virtuální reality dostupné pro uživatele spolu s technologiemi pro sledování pohybu uživatele a jeho interakce s virtuálním prostředím. Jsou v ní také vysvětleny problémy při zavádění virtuální reality do pracovního prostředí, a nakonec je uvedeno několik příkladů využití virtuální reality v průmyslu. Druhá část se zaměřuje na jednu z těchto možností využití virtuální reality – architektonickou vizualizaci, přičemž je v ní popsána její evoluce, jsou v ní porovnány softwarové možnosti pro její tvorbu a zobrazování, a nakonec je ukázán příklad přenesení reálné místnosti do virtuální podoby. Závěr se zaměřuje na možnosti rozvoje virtuální reality, výsledky porovnání softwarů pro architektonickou vizualizaci a proces tvorby příkladu vizualizace.
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