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MAC Protocol for Wireless Sensor Networks
Michálek, Tomáš ; Krajsa, Ondřej (referee) ; Červenka, Vladimír (advisor)
The work focuses on introduction to the topic of wireless sensor networks and brings readers the various aspects of problem solving in these networks. Work is closely focused on the energy performance when communicating between devices on a network and discusses the causes of excessive energy consumption. It also addresses the mechanisms for saving energy and is also engaged today protocols that its contribution to proposing solutions to problems. The author had also proposes an adapted protocol, based on lessons learned from previous theoretical sources.
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Simulation of ADSL error protection systems
Bernat, Zbyněk ; Krajsa, Ondřej (referee) ; Šilhavý, Pavel (advisor)
The main objective of this thesis was to create a model of forward error correction (FEC) system used in ADSL modem, which will be able to check its individual settings using the test methods specified in Recommendation G.996.1. The work is divided into two basic parts – theoretical and practical. The first part describes the basic functional characteristics of ADSL system, with attention being paid to aspects affecting the activity and setting of the error protection system. There are also discussed the theoretical basics of FEC coding techniques used in ADSL. The work also contains a description of the method for testing DSL system resistance against impulsive interference, which is specified in Recommendation G.996.1. The practical part of this thesis contains a description of the proposed model of the FEC system. The model was implemented in the programming environment Matlab Simulink. The proposed model includes the simulation of FEC coding process, DMT modulation and transmission channel with the impulse interference and the background noise. The proposed program is able to calculate parameters for setting FEC system from the specified data transfer rates and the requirement for interleaving. In addition, allows you to set the parameters of transmission line and sources of impulse interference and of the background noise. Under the set of input characteristics of the transmission is calculated bit allocation and the resulting parameters are given to a computational core of the model. In the application can be performed two types of test tasks. The first one is based on the Recommendation G.996.1 and makes it possible to determine probability of errored second. The second test task is for the measurement of resistance of the transmission system against impulsive interference. The results of the simulations are summarized in the conclusion of work.
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Echo suppressor according to G.168 recommendation
Lajtkep, Tomáš ; Krajsa, Ondřej (referee) ; Sysel, Petr (advisor)
This master’s thesis deals with conditions and procedures of testing network echo cancellers according to recommendation ITU-T G.168. The point of it’s interest is design of test application which will perform the objective testing their basic and extended features in MATLAB. Theoretical section is concentrated on declaration the ground of echo cancellers and conditions of their testing. Procedures of particular tests follow in next part. The last section designs the testing function which results in entire application which tests submitted canceller and in chosen file write out the report and is also able to display results like graph.
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Emulation of infrastructure unit for inteligent transport system
Giertl, Juraj ; Krajsa, Ondřej (referee) ; Balík, Miroslav (advisor)
The thesis deals with the study of communication models for cooperative intelligent transport systems and the development of the application used for testing. The ETSI ITS-G5 and IEEE 1609.x DSRC/WAVE comunication stacks were compared to standartizes layered ISO/OSI reference model. The basic principes of comunication in inteligent transport systems are described for each model. Besides that the common messages structures for defining alert messages, the intersection geometry and trafic lights signals are described in further detail. Based on these structures and other requirements, an application is created that allows easy definition of alert messages, intersection geometry and its traffic light states.
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Testing of SIP implementations in open source PBX's
Papež, Nikola ; Krajsa, Ondřej (referee) ; Šilhavý, Pavel (advisor)
This diploma thesis examines and compares several selected libraries of SIP protocol, performance, stability, security and impact of their configuration. The main functions of the signalling protocol are briefly named at the beginning. The following chapters describe the tested PBXs and several stacks for SIP protocol are theoretically compared. The practical part deals with measurements conducted on the load generator Spirent TestCenter C1 which is used for all the performed tests on exchanges. All the mentioned SIP libraries, PBXs and the operating system on which the PBXs were running are open source software.
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Protocol IPv6 and its implementation scenarios
Rýzner, Zdeněk ; Krajsa, Ondřej (referee) ; Lambertová, Petra (advisor)
This thesis deals with IPv6 – the Internet layer protocol and its situation in today’s Internet. In theoretical part are described major changes, which the new protocol brings to networking area – especially addressing, headers format and autoconfiguration. Comparison of IPv6 and IPv4 is also included. Practical part covers connecting to IPv6-Internet with selected transition methods, analyses these methods and features its implementation in dependence on network environment.
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Design and implementation of the LCD display drivers for Raspberry Pi
Cepl, Miroslav ; Lattenberg, Ivo (referee) ; Krajsa, Ondřej (advisor)
The aim of the course work is to design and implement a driver for touchscreen LCD display. The premise of the connection the display to the microcontroller using the I2C bus and use MCP23017 circuits. Raspberry Pi B + will be used for communication with circuits MCP23017 via I2C bus. Display TFT_320QVT will be connected to the outputs of extension circuits MCP23017. Part of the display complete is also a touchscreen with XPT2046 controller. Raspberry Pi runs on Raspbian system based on the Debian Linux distribution. The driver will serve to communicate and display information on the screen. The complete will be useable for applications such as selecting settings and show main information on the display.
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Model of transmission channel for xDSL systems
Jedlička, Zdeněk ; Číž, Radim (referee) ; Krajsa, Ondřej (advisor)
This bachelor thesis introduces the xDSL systems, shows the distribution of group members to symmetric and asymmetric, and shows the possibility of modeling the transmission channel for xDSL systems. It also gives ways you can get primary and secondary cable parameters and shows the potential of simulation. These parameters are used to calculate the transfer function, embedded input impedance and attenuation using the program, which is an integral part of this work.
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Design and implementation of managed PoE injector
Frkal, Pavel ; Frolka, Jakub (referee) ; Krajsa, Ondřej (advisor)
This study deals with power supply for network devices using existing structured cabling. Various power supplies are analysed including their limitations and also deals with measuring of the consumed energy. The outcome is 24-port passive PoE injector for remote power supply of network equipment. It's suitable namely for remote devices which lacks built-in PoE support as these do not need major modifications (using passive injection). Power options including current measurement may be done via administrative web interface.
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