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Protection of data transmission against long error bursts
Malach, Roman ; Lambertová, Petra (referee) ; Němec, Karel (advisor)
This Master´s thesis discuses the protection of data transmission against long error bursts. The data is transmited throught the channel with defined error rate. Parameters of the channel are error-free interval 2000 bits and length of burst error 250 bits. One of the aims of this work is to make a set of possible methods for the realization of a system for data correction. The basic selection is made from most known codes. These codes are divided into several categories and then the best one is chosen for higher selection. Of course interleaving is used too. Only one code from each category can pass on to the higher level of the best code selection. At the end the codes are compared and the best three are simulated using the Matlab program to check correct function. From these three options, one is chosen as optimal regarding practical realization. Two options exist, hardware or software realization. The second one would seem more useful. The real codec is created in validator language C. Nowadays, considering language C and from a computer architecture point of view the 8 bits size of element unit is convenient. That´s why the code RS(255, 191), which works with 8 bits symbols, is optimal. In the next step the codec of this code is created containing the coder and decoder of the code above. The simulation of error channel is ensured by last program. Finally the results are presented using several examples.
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Power line parameters
Kavan, Pavel ; Krajsa, Ondřej (referee) ; Mlýnek, Petr (advisor)
At the beginning is diploma thesis focused on a distribute power line parameters measurement and examination changes of this parameters depending on using of various power line cables. On the basis of measurements is made a transmission channel in Matlab & Simulink, where are executed simulations with power transmission line. The simulated power line is based on measured distribute parameters or physical proportions of cabels. By changing different parts of simulated communication channel is a symbol error rate expressed on the lenght of transmission line.
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Modulator and demodulator for microwave link
Martinec, Matěj ; Frydrych, Jiří (referee) ; Záplata, Filip (advisor)
This work is dealing with the design of intermediate part of transmitter and reciever that use digital BPSK and QPSK modulations for microwave link that works in 24 – 26 GHz bands. Besides choosing the suitable modulator and demodulator there was need to provide proper connection of this part with transceiver Nortel CTR26-01M. Input and output of this intermediate part was take out to baseband, where was need to ensure the transfer of diferential inputs of modulator and demodulator to symetric leading for reason of data communication with PC, for which was created the algorithms to provide transmitting and receiving data. Complete structure controlled by the microcontroller has been enliven and furthemore there was created the measurement of chosen parameteres.
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Simulated Fault-Injection in Network Communication
Rozsíval, Michal ; Rogalewicz, Adam (referee) ; Smrčka, Aleš (advisor)
The development of network applications takes place under ideal conditions, as opposed to deploying them in a real-world environment that contains vulnerabilities such as loss, latency, or cyber-attacks. Ensuring resilience against these vulnerabilities is thus crucial. This thesis introduces the NetLoiter, which aims to enable the simulation of the required vulnerabilities and thus allow developers to treat them correctly. The NetLoiter can be used in transparent (proxy server), hidden (captures communication directly from the system kernel), or hardware versions suitable for testing embedded systems. NetLoiter supports dynamic reconfiguration using a public interface that can be used to automate the testing process. NetLoiter has been successfully integrated and used in real projects.
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Accuracy and fluency in the speech of the advanced learner of English
Gráf, Tomáš ; Klégr, Aleš (advisor) ; Šebesta, Karel (referee) ; Betáková, Lucie (referee)
The thesis analyses the accuracy and fluency exhibited in the spoken advanced-learner English of Czech students of English philology. It draws its data from a learner corpus comprising fifty 15-minute interviews with these learners and from a parallel native-speaker corpus of forty-nine 15-minute interviews. As regards accuracy, the learner data is analysed using techniques of error analysis. Salient features of advanced learner English are identified and the subsequent quantitative analyses reveal that throughout the entire group of students (which is characterized by what revealed itself to be a wide proficiency span) two groups of error types are found to be much more frequent than any other, namely errors in the use of articles and tenses. For the fluency measurements a small selection of variables has been chosen to describe speed fluency (speech rate) and breakdown fluency (the frequency of unfilled and filled pauses), and the results are compared with those for the parallel native-speaker corpus. The analysed native speakers are found to produce speech at a generally much higher rate than the majority of the learners. There does not appear - at least in the light of the given sample - to be any direct correlation between fluency and the frequency of errors. Moreover, the learners are found...
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Accuracy and fluency in the speech of the advanced learner of English
Gráf, Tomáš ; Klégr, Aleš (advisor) ; Šebesta, Karel (referee) ; Betáková, Lucie (referee)
The thesis analyses the accuracy and fluency exhibited in the spoken advanced-learner English of Czech students of English philology. It draws its data from a learner corpus comprising fifty 15-minute interviews with these learners and from a parallel native-speaker corpus of forty-nine 15-minute interviews. As regards accuracy, the learner data is analysed using techniques of error analysis. Salient features of advanced learner English are identified and the subsequent quantitative analyses reveal that throughout the entire group of students (which is characterized by what revealed itself to be a wide proficiency span) two groups of error types are found to be much more frequent than any other, namely errors in the use of articles and tenses. For the fluency measurements a small selection of variables has been chosen to describe speed fluency (speech rate) and breakdown fluency (the frequency of unfilled and filled pauses), and the results are compared with those for the parallel native-speaker corpus. The analysed native speakers are found to produce speech at a generally much higher rate than the majority of the learners. There does not appear - at least in the light of the given sample - to be any direct correlation between fluency and the frequency of errors. Moreover, the learners are found...
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Modulator and demodulator for microwave link
Martinec, Matěj ; Frydrych, Jiří (referee) ; Záplata, Filip (advisor)
This work is dealing with the design of intermediate part of transmitter and reciever that use digital BPSK and QPSK modulations for microwave link that works in 24 – 26 GHz bands. Besides choosing the suitable modulator and demodulator there was need to provide proper connection of this part with transceiver Nortel CTR26-01M. Input and output of this intermediate part was take out to baseband, where was need to ensure the transfer of diferential inputs of modulator and demodulator to symetric leading for reason of data communication with PC, for which was created the algorithms to provide transmitting and receiving data. Complete structure controlled by the microcontroller has been enliven and furthemore there was created the measurement of chosen parameteres.
|
|
|
Power line parameters
Kavan, Pavel ; Krajsa, Ondřej (referee) ; Mlýnek, Petr (advisor)
At the beginning is diploma thesis focused on a distribute power line parameters measurement and examination changes of this parameters depending on using of various power line cables. On the basis of measurements is made a transmission channel in Matlab & Simulink, where are executed simulations with power transmission line. The simulated power line is based on measured distribute parameters or physical proportions of cabels. By changing different parts of simulated communication channel is a symbol error rate expressed on the lenght of transmission line.
|
|
|
Protection of data transmission against long error bursts
Malach, Roman ; Lambertová, Petra (referee) ; Němec, Karel (advisor)
This Master´s thesis discuses the protection of data transmission against long error bursts. The data is transmited throught the channel with defined error rate. Parameters of the channel are error-free interval 2000 bits and length of burst error 250 bits. One of the aims of this work is to make a set of possible methods for the realization of a system for data correction. The basic selection is made from most known codes. These codes are divided into several categories and then the best one is chosen for higher selection. Of course interleaving is used too. Only one code from each category can pass on to the higher level of the best code selection. At the end the codes are compared and the best three are simulated using the Matlab program to check correct function. From these three options, one is chosen as optimal regarding practical realization. Two options exist, hardware or software realization. The second one would seem more useful. The real codec is created in validator language C. Nowadays, considering language C and from a computer architecture point of view the 8 bits size of element unit is convenient. That´s why the code RS(255, 191), which works with 8 bits symbols, is optimal. In the next step the codec of this code is created containing the coder and decoder of the code above. The simulation of error channel is ensured by last program. Finally the results are presented using several examples.
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Error rate in writing at children with dysorthographia
STAŇKOVÁ, Marie
The thesis is focused on studies of dysorthographia, one of the specific learning difficulties. The theoretical part deals with specific learning difficulties in general, characterizes the concrete term of dysorthographia in view of its types, causes and symptoms, mentions some diagnostic methods in use and some corrective techniques. This part also indicates the impact of the introduced difficulties on various schoolwork areas as well as on the everyday life. The research part follows some types of errors together with error rate in writing at children with dysorthographia and at children without this diagnosis.
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