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Analysis and Improvement of Distributed Systems
Kenyeres, Martin ; Sýkora, Jiří (referee) ; Klučik,, Stanislav (referee) ; Škorpil, Vladislav (advisor)
A significant progress in the evolution of the computer systems and their interconnection over the past 70 years has allowed replacing the frequently used centralized architectures with the highly distributed ones, formed by independent entities fulfilling specific functionalities as one user-intransparent unit. This has resulted in an intense scientic interest in distributed algorithms and their frequent implementation into real systems. Especially, distributed algorithms for multi-sensor data fusion, ensuring an enhanced QoS of executed applications, find a wide usage. This doctoral thesis addresses an optimization and an analysis of the distributed systems, namely the distributed consensus-based algorithms for an aggregate function estimation (primarily, my attention is focused on a mean estimation). The first section is concerned with a theoretical background of the distributed systems, their evolution, their architectures, and a comparison with the centralized systems (i.e. their advantages/disadvantages). The second chapter deals with multi-sensor data fusion, its application, the classification of the distributed estimation techniques, their mathematical modeling, and frequently quoted algorithms for distributed averaging (e.g. protocol Push-Sum, Metropolis-Hastings weights, Best Constant weights etc.). The practical part is focused on mechanisms for an optimization of the distributed systems, the proposal of novel algorithms and complements for the distributed systems, their analysis, and comparative studies in terms of such as the convergence rate, the estimation precision, the robustness, the applicability to real systems etc.
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Classification of material used for the construction of garden ponds
Sýkora, Jiří ; Repková, Martina (referee) ; Komendová, Renata (advisor)
This thesis deals with the study of the occurrence forms of inorganic phosphorus in water garden ponds and used material impact on the amount of releasable amount of phosphorus in the form of phosphates in the water medium. The practical part of this work focuses on the analysis and subsequent classification of building materials for the production of garden ponds just by releasing ability of phosphorus in the form of phosphates in the water.
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The use of Electrical Properties of Composites with Modified Cement Matrix
Macháň, Ladislav ; Husák, Miroslav (referee) ; Sýkora, Jiří (referee) ; Šteffan, Pavel (advisor)
The dissertation thesis is focused on practical use of composite material with modified cement matrix. Especially the area of electrical behavior of composite materials in use has been examined, for strain sensing material. The experimental part solves the problematics of corrosion of carbon and metallic materials in alkaline environment of the cement matrix. The physical design of the sensor and its fabrication using functional composite cement material have been described here. The thesis has also discussed defining the influence of temperature change and humidity change on the change of electrical parameters of integrated sensors. An important part of the thesis is the area of evaluating a series of measurements of electrical parameters under dynamic loading. The thesis analyzes designed measurement method in detail, being suitable to determine electrical properties of cement composite materials including the construction of a monitoring system that enables practical application of sensors in complex structures.
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Microelectronics Time-Space Authentication Techniques
Jaroš, David ; Burda, Karel (referee) ; Sýkora, Jiří (referee) ; Kuchta, Radek (advisor)
This dissertation work focusses on using information about the location of the user during the authentication process on computer networks. With the growth of mobile computer devices over the last two decades the physical location of users is becoming one of the main issues for access management. This work researches existing solutions which are divided in to two groups related to the source of location information (SATNAV systems for example GPS and based on communication with active infrastructure such as GSM, Wi-Fi). This work shows the methodology for evaluating authentication data which use the principle of fuzzy logic. In comparison with binary logic it is possible to evaluate authentication data accurately. As a result of the authentication process the information is of a higher value, which can be taken into account when setting the levels of user privileges. An important aspect of working with location information is that the user is located in the same place and from where they are asking for access to the system. Solving this question could be linking user biometrics for example finger prints. This principle is used in two types of microelectronic authentication terminals which were developed in conjunction with this work. The first type of terminal uses a SATNAV receiver and an ISM wireless communication module as a source of location information. On the first type of authentication terminal newly developed authentication techniques were tested. The users biometrics are checked by finger print sensor with embedded processing. In the second type authentication terminal a Wi-Fi and GSM module were added for location purposes. In the conclusion of this dissertation the testing methodology of the data authorization and evaluation process of the second type of microelectronic authentication terminal is shown. This confirms the practicality of the suggested methodology and the time-space information in the authentication process.
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Steel footbridge for pedestrians and cyclists
Sýkora, Jiří ; Pešek, Ondřej (referee) ; Štrba, Michal (advisor)
The aim of the work is to design a steel footbridge for pedestrians and cyclists in Brno. This is a valley bridge where there is no road for vehicles. All motor vehicles are not allowed to entering the footbridge. The theoretical span of the bridge is 50 m, the height of the structure is 7 m. The bridge deck is elevated by 0,5 m in the arch. Two variants have been proposed. The more suitable one was selected by comparison according to several criteria, for which a detailed structural analysis and drawings were prepared.
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Converged Networks and Traffic Tomography by Using Evolutionary Algorithms
Oujezský, Václav ; Sýkora, Jiří (referee) ; Polívka, Michal (referee) ; Škorpil, Vladislav (advisor)
Nowadays, the traffic tomography represents an integral component in converged networks and systems for detecting their behavioral characteristics. The dissertation deals with research of its implementation with the use of evolutionary algorithms. The research was mainly focused on innovation and solving behavioral detection data flows in networks and network anomalies using tomography and evolutionary algorithms. Within the dissertation has been proposed a new algorithm, emerging from the basics of the statistical method survival analysis, combined with a genetics’ algorithm. The proposed algorithm was tested in a model of a self-created network probe using the Python programming language and Cisco laboratory network devices. Performed tests have shown the basic functionality of the proposed solution.
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Quality of Service in Converged Systems with Elements Controlled by Neural Network
Polívka, Michal ; Sýkora, Jiří (referee) ; Křepelka, Václav (referee) ; Škorpil, Vladislav (advisor)
The Quality of Service (QoS) is in converged systems an important parameter. The dissertation thesis deals with research of QoS implementation into a newly developed network element. There was designed and implemented new protocol, based on the IP. The dissertation thesis deals with proposal of a new network element – the switch controlled by a neural network. During the research have been measured switches cross a performance classes. On the base of the measurement was designed the new four-port switch with switch fabric build on crossbar switch with an external control. The switch was designed with maximum QoS support. The switch fabric is controlled by the feedforward backpropagation neural network. The designed switch was modeled in the MATLAB and Simulink. The simulations prove that developed solution is functional.
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Roof Structure of Collection Yard
Sýkora, Jiří ; Štrba, Michal (referee) ; Pilgr, Milan (advisor)
The roof structure has plan dimensions of 9.15 m in width and 38.4 m in length, the height of the structure is approximately 5.9 m. The planar load-carrying system in the transverse direction consists of a fixed column and a beam with a slope of 8°, which is supported by the column both directly in the middle of the length and by means of hinges in quarters of the length. These transverse support systems are spaced at 6 m intervals. The roof cladding made of profiled steel sheeting metal is supported on plain purlins placed perpendicularly on the load-carrying system. The spatial rigidity of the structure is ensured in the transverse direction by the fixed of the columns and in the longitudinal direction by the truss bracing. The supporting structure consists of hot rolled steel profiles.
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Multiplatform communication in access networks
Novotný, Bohumil ; Sýkora, Jiří (referee) ; Křepelka, Václav (referee) ; Škorpil, Vladislav (advisor)
Doctoral thesis deals with failure detection methods in wireless access network using distributed stochastic algorithms. A new method of detecting a fault based on the push-sum algorithm has been designed and simulated. Within the scope of the work objectives, the statistical credibility of the average push-sum protocol convergence rate representative and the effect of message loss during the calculation on the robustness of the system using this protocol were compared. Based on the acquired knowledge, the ability of the protocol to mathematically derive deviations from the real average of the values in the specified topology was demonstrated and thereby the existence of an abnormality in the network has been proved or refuted.
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