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Modeling of planar antenna loaded with ring resonators
Šrajbr, Michal ; Kovács, Peter (referee) ; Láčík, Jaroslav (advisor)
This bachelor’s thesis is focused on the design of the dual-band printed dipol loaded with split ring resonators. The principal of this antenna is described in the first part. The main focus is on the design and tuning of the split ring resonators on the required working frequency in the CST Microwave Studio program. These results are used for designing dual-band printed dipol loaded with split ring resonators working at resonance frequencies of 1,8 a 2,4 GHz. The simulation of this antenna was performed in the IE3D program Zeland. The designed dual-frequency printed dipole has been manufactured and measured.
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Finding invariances in sensory coding through gradient methods.
Kovács, Peter ; Antolík, Ján (advisor) ; Šikudová, Elena (referee)
The key to understanding vision is to acquire insight into the sensory coding of indi- vidual neurons. To this end, major advances were done over the past 50 years in fitting models to neural data to identify the mapping from sensory space to neural responses. Especially the advance of DNNs in neuroscience allowed for model fits with excellent predictive power. However, such advanced neural models are complex, and their poor in- terpretability has so far hindered deeper understanding of the principles of visual coding. To address this issue, a recent study proposed a method which identifies the stimulus that activates the neuron the most. However, the sensory coding of highly non-linear neurons, which are abundant already at the earliest stages of visual processing, is too complex for a single stimulus to sufficiently characterize it. A more robust way to char- acterize this coding is through identifying the input sub-space within which the neuron is activated identically - i.e. finding invariances of the neuron's sensory representation. In this thesis, a novel approach for finding such invariant stimuli is proposed. The proposed technique is based on a generator neural network, which maps Gaussian noise from latent space to a stimulus set which equally activates a given neuron. The method demonstrated the...
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Ant colony optimization
Kovács, Peter ; Pangrác, Ondřej (advisor) ; Balko, Martin (referee)
The aim of this work was to compare metaheuristic Ant Colony with other metaheuristics like Simulated Annealing, Tabu Search or Greedy algo- rithms. Metaheuristics were compared on three different NP-hard problems. Specificaly, Traveling Salesman Problem, Graph Coloring Problem and Set Covering Problem. Detailed description of implementation of metaheuristics in particular problems can be found in this work. Metaheuristics were com- pared based on cost function and execution time. However, this work tries to identify instances, in which Ant Colony was the best choice. Ant Colony is reliable metaheuristic on large Traveling Salesman or Set Covering problems.
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Diabetes mellitus, environmental and genetic risk factors
Procházková, Iveta ; Hubáček, Jaroslav (advisor) ; Kovacs, Peter (referee)
Diabetes mellitus (DM) is globally widespread group of diseases characterised by increased blood glucose. There are several types, the most common is type 1 DM and type 2 DM. Multifactorial polygenic inheritance is typical for DM with exeption of couple monogenic forms. Type 1 DM is autoimmune form usually manifesting since childhood. Its manifestation is influenced mostly by HLA system genotype, but also by non-HLA genes together with environmental factors, amongst which nutrition of the children is predominant. Type 2 DM develops usually in adulthood. The development is influenced by obesity and lack of movement, but the individual sensitivity to type 2 DM is also genetically determined. Main genetic factors are variations in genes TCF7L2 and FTO as well as in genes coding cyclin dependent kinases.
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Band-pass filter integration into the planar antenna structure
Miřácký, Jan ; Kovács, Peter (referee) ; Všetula, Petr (advisor)
The Bachelor´s thesis includes the description of the design, numerical analyses and optimalization of three band-pass planar microstrip filters which operate in microwave band. Parameters of individual band-pass filters are mutually compared and then the filters are integrated to the required planar antenna structure. The thesis also includes a numerical model and detailed analysis of a patch antenna in program CST Microwave Studio. The integrated structure with the best parameters is experimentally fabricated and measured.
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Modeling of planar antenna loaded with ring resonators
Šrajbr, Michal ; Kovács, Peter (referee) ; Láčík, Jaroslav (advisor)
This bachelor’s thesis is focused on the design of the dual-band printed dipol loaded with split ring resonators. The principal of this antenna is described in the first part. The main focus is on the design and tuning of the split ring resonators on the required working frequency in the CST Microwave Studio program. These results are used for designing dual-band printed dipol loaded with split ring resonators working at resonance frequencies of 1,8 a 2,4 GHz. The simulation of this antenna was performed in the IE3D program Zeland. The designed dual-frequency printed dipole has been manufactured and measured.
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Design and Optimization of Electromagnetic Band Gap Structures
Kovács, Peter ; Škvor,, Zbyněk (referee) ; Dědková, Jarmila (referee) ; Lukeš, Zbyněk (advisor)
Dizertační práce pojednává o návrhu a optimalizaci periodických struktur s elektromagnetickým zádržným pásmem (EBG – electromagnetic band gap) pro potlačení povrchových vln šířících se na elektricky tlustých dielektrických substrátech. Nepředvídatelné chování elektromagnetických vlastností těchto struktur v závislosti na parametrech elementární buňky činí jejích syntézi značně komplikovanou. Bez patřičného postupu je návrh EBG struktur metodou pokusu a omylu. V první části práce jsou shrnuty základní poznatky o šíření elektromagnetických vln v tzv. metamateriálech. Následně je diskutován správný způsob výpočtu disperzního diagramu ve vybraných komerčních programech. Jádrem dizertace je automatizovaný návrh a optimalizace EBG struktur využitím různých globálních optimalizačních algoritmů. Praktický význam vypracované metodiky je předveden na návrhových příkladech periodických struktur s redukovanými rozměry, dvoupásmovými EBG vlastnostmi, simultánním EBG a AMC (artificial magnetic conductor – umělý magnetický vodič) chováním a tzv. superstrátu. Poslední kapitola je věnována experimentálnímu ověření počítačových modelů.
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Low Profile Integrated Antenna for GPS and DRSC
Kolb, Lukáš ; Kovács, Peter (referee) ; Raida, Zbyněk (advisor)
In the project, planar antennas for receiving satellite GPS signals and DSRC ones were investigated and mutually combined. The combined antenna was designed for the substrate ARLON, CuClad 217 LX, was modeled and optimized in the program ANSOFT Designer. Attention was turned to the proper impedance matching, directivity properties and polarization properties. The designed antenna was built and their properties were experimentally verified.
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Patch antenna completed by multiband ground plane
Syrový, Jiří ; Kovács, Peter (referee) ; Láčík, Jaroslav (advisor)
This thesis is aimed on multiband plannar antennas. The features of free stand-alone patch antenna and frequency selective surfaces (FSS) are needed to be investigated. The stand-alone rectangular patch antenna is analyzed in Ansoft Designer. All other results are achieved using CST Microwave studio. The final product is multiband triangle patch antenna with two frequency selective reflectors formed by FSS. The results of particular analysis are compared with theory published in literature.
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