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The comparison of voiced and unvoiced consonant pairs
Šablatúra, Šimon ; Smékal, Zdeněk (referee) ; Jirásek, Ondřej (advisor)
This bachelor’s thesis deals with the comparison of voiced and unvoiced consonants. The aim of the work is the analysis of the pronunciation of single consonants in different languages. Five pairs of voiced and unvoiced consonants were selected for this work and were recorded by five narrators. Subsequently, these recordings were analyzed in the Matlab, Praat and Excel programs, where spectra, formant regions and directional characteristics of single consonants were compared. These analyzes were related to the physiological formation of consonants in the given language. The selected languages for this work are Spanish, Slovak, Czech and Russian.
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Analysis of tonal inharmonic spectra
Sztefek, Jiří ; Mojdl, Edgar (referee) ; Jirásek, Ondřej (advisor)
The bachelor thesis focuses on the spectral analysis of samples of tonal inharmonic instruments and their spectra, with a detailed focus on the present overtones, their properties, waveforms, relationships and numerical ratios between each other, interval types and categorization into critical bandwidths. Eight samples of acoustic and five samples of artificial instruments were analysed as part of the work. The analysis of the samples was performed using Fourier transform in MATLAB with a focus on FFT spectra and spectrogram. The results of the work are intended for musicians or scientists concerned with inharmonic components in sound and their properties.
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Ablation chamber for a combination of LIBS and LA-ICP-MS techniques
Sovadina, Petr ; Kuchynka, Michaela (referee) ; Novotný, Jan (advisor)
Laser-induced breakdown spectroscopy (LIBS) and laser ablation inductively coupled plasma mass spectroscopy (LA-ICP-MS) are spectroscopic techniques that use a pulsed laser to ablate the material in their analysis. Although LA-ICP-MS can reach a much lower detection limit than LIBS, it is not able to detect elements of organic compounds, halogens, and noble gases. By combining these two spectroscopic techniques, it is possible to overcome these shortcomings, to analyze all elements with LIBS, and also to analyze with a lower detection limit with LA-ICP-MS. To perform this combination of spectroscopic techniques, it was necessary to design an ablation chamber that would simultaneously support both LIBS and LA-ICP-MS measurements. The design of the ablation chamber consists of the mechanical design, the simulation of the gas flow inside the chamber, and finally its fabrication and assembly.
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MIDI transducer design and cymbal colour upgrade with artificial components
Pospíšil, Martin ; Buzzi, Mário (referee) ; Jirásek, Ondřej (advisor)
This bachelor thesis deals with MIDI transducer design and cymbal color innovation with artificial components. The goal of the thesis was to design and fabricate a converter that converts audio signals from cymbals to the MIDI standard while capturing the widest dynamic range. Furthermore, a spectral analysis of several types of cymbals was performed and a program was created that adds artificial components such as filtered noise and additive inharmonic clusters to their acoustic color. The result of this work is a working prototype MIDI transducer and a program implemented in NI Reaktor software that allows the creation of acoustic presets with the upgraded cymbal color. The work met the stated objectives and provided a basis for further development in this area.
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Spectral analysis of historical pianos
Pokorný, Marek ; Indrák, Michal (referee) ; Jirásek, Ondřej (advisor)
This bachelor thesis focuses on the spectral analysis of historical pianos in aim to identify and compare their acoustic and spectral characteristics. Three examples of pianos were analysed, including a significant piano owned by the composer Leoš Janáček. The analysis was performed on measured piano samples using Fourier transformation in MATLAB, with an emphasis on spectral parameters such as spectral centroid, flatness, skewness, sharpness and roughness, and on the visual representation of a spectrum over time -- the spectrogram. The results of the spectral analysis were used to interpret and evaluate differences in timbre of the pianos and their probable causes. The theoretical part of the thesis provides a brief overview of the history and design of the piano, explains the spectral descriptors used, and examines the properties of musical tones and the influence of psychoacoustics on the perception of pitch and timbre.
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Analysis and forecasting of timeseries in financing
Maňásek, Erik ; Hübnerová, Zuzana (referee) ; Hrabec, Pavel (advisor)
The topic of this bachelor thesis is the technical analysis of stock market financial time series. The thesis discusses the method of decomposition into individual components, methods of analysis and prediction of these components. It also provides a comparison of the methods used, their evaluation and an outline of some of their characteristics, both good and bad.
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Utilization of vibrational spectroscopy in structural analysis of microbially produced alginates
Kianička, Michal ; Enev, Vojtěch (referee) ; Sedláček, Petr (advisor)
This bachelor thesis focuses on the characterization of alginates using the main vibrational methods FTIR-ATR and Raman spectroscopy, supplemented by the carbazole method and thermogravimetry (TGA). The main objective was to utilize these analytical tools to study commercially available alginates and determine their monomeric composition. For this purpose, a calibration set was created using the ratios of poly(mannuronic acid) and poly(guluronic acid) standards, which was then used to analyze commercial alginates. The thesis focused on two forms of alginates - acidic and alkaline salts, aiming for a better understanding of their composition and subsequent application. The thesis revealed that the vibrational methods used were effective in analyzing the calibration sets, providing calibration curves for determining the composition of alginates. However, in the actual analysis of commercial alginates, these methods were found to be insufficiently accurate and reliable. Possible explanations include the presence of additional components in commercial samples or the influence of molecular weight. The results of the thesis indicate the need for further research tasks aimed at improving the accuracy and effectiveness of vibrational methods in the analysis of commercial alginates.
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Involvement of vibrational spectroscopy in the in-situ analysis of PHA in bacterial biomass.
Kevélyová, Barbora ; Samek, Ota (referee) ; Sedláček, Petr (advisor)
The aim of this thesis was the study of polyhydroxyalkanoates in bacterial biomass using the ATR-FTIR method. Furthermore, the PCA method was chosen to evaluate the measured data and observe correlations or differences among the spectra of various biomass samples. The bacterial producents were Aneurinibacillus thermoaerophilus H1, AH30 and AFn2, Cupriavidus malaysiensis DSM 25816, DSM 19416 and DSM 19379 and three strains of Schlegelella thermodepolymerans M 15344, DSM 15264 and LMG 21645. Various heteropolymers with different monomer content and total PHA content were investigated. The monomers in the samples were 3-hydroxybutyrate, 4-hydroxybutyrate, 3-hydroxyvalerate, 4-hydroxyvalerate, 5-hydroxyvalerate and 4-hydroxyhexanoate. As the reference method for accurate quantitative and qualitative determination of polyhydroxyalkanoates in the samples, gas chromatography was performed. The spectra obtained by the FTIR method were compared and significant peaks related to the qualitative properties of PHA, namely monomer composition and crystallinity, were searched for. The PCA statistical method was successfully applied to the collected data from FTIR, with the help of which the qualitative differences between the samples were monitored. The most significant differences were observed in the presence of monomers 4-hydroxybutyrate and 4-hydroxyhexanoate, and they were related to the crystallinity of the samples. The analysis did not show potential for semi-quantitative determination of PHA in biomass. Differences between microorganisms were not observed. The procedure for evaluating FTIR spectra using PCA could in the future be used in the study of biomass containing various monomeric units, especially hydroxyvalerates in case of their higher content within the sample.
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Spectral Analysis of EEG Signal
Miklenda, Petr ; Orság, Filip (referee) ; Kupková, Karolína (advisor)
This bachelor thesis is focused at the EEG signal analysis using the Fast Fourier Transform. The theoretical part consist of EEG signal description, its creation and selected method for signal analysis. The practical part presents program for recording data from EEG headset and displaying the Fourier spectrum.
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