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Possibilities of Error Controls in Frequency hopping Stations
Pust, Radim ; Kovář, Pavel (referee) ; Wieser,, Vladimír (referee) ; Burda, Karel (advisor)
The doctoral thesis deals with design of coding for frequency hopping stations in band with intensive jamming. In digital modulations erroneous determination of the modulation state occurs due to jam at the receiver side. The result is erroneously transferred symbols of the message. Errors created during the transmission can be eliminated by using error control systems. It is also possible to prevent these errors by using algorithms (techniques) of frequency hopping which select the appropriate channel. Appropriate communication channel is a channel with a lower probability of erroneous symbol in the message. The main contribution of this thesis is to design a new frequency hopping technique with collision avoidance (FH/CA). The station with FH/CA technique measures signal levels in the considered several channels before every jump. Based on the measurements the most appropriate channel with the lowest value of measured signal level is selected. Therefore, it is more probable that a jump to an unoccupied channel with a transmission will occur. Using a mathematical model, the performance of the newly proposed FH/CA technique is compared with the currently used techniques FH and AFH. Comparison criteria are the probability of a collision between an FH/CA communication system and a static (device transmitting continuously at a fixed frequency) or dynamic jammer (i.e. other FH or AFH systems). By comparing the values of the probability of jammed transmission, indisputable theoretical advantages of the new FH/CA technique were found, compared to the currently used FH and AFH techniques. The FH/CA technique always has better or equal results compared with the FH technique in the case of interference by static and dynamic jammers. The FH/CA technique in a band with static and dynamic jammers usually has better results than the AFH technique. A significant contribution of the FH/CA technique can be seen in the case of dynamic jammers. On the other hand, in the case of static jammers the FH/CA technique is in certain situations worse than the AFH technique. The accuracy of the mathematical models were successfully verified on a simulation model that was created as a part of this thesis in the MATLAB environment. Based on the obtained data from the model there was designed coding for frequency hopping stations with the new technique of frequency hopping FH/CA which is designed for small-volume data transfer in a band with intensive jamming.
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Genetic factors of familial hyperlipidemia and prevention of cardiovascular diseases
Todorovová, Veronika ; Češka, Richard (advisor) ; Blaha, Vladimír (referee) ; Karásek, David (referee)
Familial hyperlipidemias are still a current cause of premature development of atherosclerotic cardiovascular disease (ASCVD). Heredity plays an important role in the development of these diseases. Genetic testing helps to specify a definite variant of a given disease and thus the degree of genetic family burden. Together with the clinical examination, it defines the exact diagnosis of the patient and reduces the risk of developing ASCVD in individual specialized care. In the theses, we focused on biochemical and genetic differences and their risk factors for the development of ASCVD in long-term monitored patients with familial hypercholesterolemia (FH), in receptor-mediated FH and familial defect of apolipoprotein B- 100 (FDB). Efficacy, safety, and tolerability of therapy were evaluated in a subgroup of FH patients with PCSK9i therapy. Furthermore, the polygenic genetic risk score (GRS) in patients with the APOE2E2 genotype and its influence on the early detection of the development of familial dysbetalipoproteinemia (FD) were analyzed. Receptor-mediated FH patients carry a mutation in LDLR while FDB patients have a prevalent mutation in APOB. LDL-C and TC levels are high in both groups, although levels are slightly higher in receptor-mediated FH patients. APOE genotype and risk factors such as...
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Morphological, immunohistochemical, and molecular analysis of leiomyocellular tumors of the female reproductive system
Gregová, Mária ; Dundr, Pavel (advisor) ; Mandys, Václav (referee) ; Škarda, Jozef (referee)
Introduction Leiomyoma with bizarre nuclei (LBN) and cellular leiomyoma (CL) are rare variants of uterine smooth muscle tumors. In diagnostic practice, LBN can be mistaken for leiomyosarcoma (LMS), while CL may mimic low grade endometrial stromal sarcoma (LG ESS). Careful evaluation of morphological features is necessary when making the diagnosis; in some borderline cases, immunohistochemical and molecular examinations may help. Literature data on molecular genetic alterations in LBN and CL is limited, but some of these tumors appear to share certain aberrations with classical leiomyomas (UL) and LMS. Aims The aim of the work is to expand the knowledge about smooth muscle tumors of the uterus, especially LBN and CL, and perform a complex morphological, immunohistochemical (IHC), and molecular evaluation of their features. The individual goals include: 1) confirmation of the hypothesized benign behaviour of LBN, 2) morphological analysis of LBN, 3) more detailed clarification of LBN tumorigenesis with a focus on the FH gene, 4) clarification of CL tumorigenesis, 5) the use of IHC FH antibody as a screening method to identify FH gene mutations, 6) the use of morphological evaluation and results of IHC examination to facilitate differential diagnostic balance between benign and malignant smooth muscle...
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Possibilities of Error Controls in Frequency hopping Stations
Pust, Radim ; Kovář, Pavel (referee) ; Wieser,, Vladimír (referee) ; Burda, Karel (advisor)
The doctoral thesis deals with design of coding for frequency hopping stations in band with intensive jamming. In digital modulations erroneous determination of the modulation state occurs due to jam at the receiver side. The result is erroneously transferred symbols of the message. Errors created during the transmission can be eliminated by using error control systems. It is also possible to prevent these errors by using algorithms (techniques) of frequency hopping which select the appropriate channel. Appropriate communication channel is a channel with a lower probability of erroneous symbol in the message. The main contribution of this thesis is to design a new frequency hopping technique with collision avoidance (FH/CA). The station with FH/CA technique measures signal levels in the considered several channels before every jump. Based on the measurements the most appropriate channel with the lowest value of measured signal level is selected. Therefore, it is more probable that a jump to an unoccupied channel with a transmission will occur. Using a mathematical model, the performance of the newly proposed FH/CA technique is compared with the currently used techniques FH and AFH. Comparison criteria are the probability of a collision between an FH/CA communication system and a static (device transmitting continuously at a fixed frequency) or dynamic jammer (i.e. other FH or AFH systems). By comparing the values of the probability of jammed transmission, indisputable theoretical advantages of the new FH/CA technique were found, compared to the currently used FH and AFH techniques. The FH/CA technique always has better or equal results compared with the FH technique in the case of interference by static and dynamic jammers. The FH/CA technique in a band with static and dynamic jammers usually has better results than the AFH technique. A significant contribution of the FH/CA technique can be seen in the case of dynamic jammers. On the other hand, in the case of static jammers the FH/CA technique is in certain situations worse than the AFH technique. The accuracy of the mathematical models were successfully verified on a simulation model that was created as a part of this thesis in the MATLAB environment. Based on the obtained data from the model there was designed coding for frequency hopping stations with the new technique of frequency hopping FH/CA which is designed for small-volume data transfer in a band with intensive jamming.
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