National Repository of Grey Literature 40 records found  beginprevious19 - 28nextend  jump to record: Search took 0.02 seconds. 
Analysis of how resonant cavities affect the spectrum and radiation of the human voice
Burešová, Natálie ; Šefčík,, Ondřej (referee) ; Jirásek, Ondřej (advisor)
This thesis deals with analysis and evaluation of how much covering resonance cavities affects spectrum and diverctivity, then human position, when he is upright and hunched over. The task was to research changing of intensity level in spectrum, directivity characteristics and how is directivity being changed in various angles according to the speaker position.
Analysis of the spectra of violas with respect to their different bodies
Smola, Ondřej ; Indrák, Michal (referee) ; Jirásek, Ondřej (advisor)
This work focuses on the spectral analysis of three different violas, the modern one, the renaissance one and viola da gamba. Further the work focuses on the formant areas, resonance modes of its resonance corpus and how the resonance modes influence the tembre of the instruments. The theoretical part deals with the history of viola, acoustic-mechanical features, which influence the wood resonance. The practical part focuses on creating the graphic forms of required data needed for spectral analysis, identifying the resonance modes of the instruments and directional characteristics. The sound spectrums of all instruments are compared across the whole practical part. The practical part contains spectrograms, graphs of LPC analysis, graphs of directional radiation and table with formant frequencies of both instruments.
Efficient implementation of methods for the restoration of damaged audio signals
Csiba, Hajnalka ; Rajmic, Pavel (referee) ; Mokrý, Ondřej (advisor)
This bachelor's thesis deals with the restoration of audio signals containing unknown samples at known locations using two algorithms. The first is the Janssen algorithm and the second is a method based on non-negative matrix factorization. Janssen algorithm is built on the principle of the autoregressive model. The restoration of the samples is performed in such a way that the restored signal matches the predicted model as precisely as possible. The algorithm based on non-negative matrix factorization is used to decompose the frequency spectrogram of the signal as the product of non-negative matrices.
Accelerated sensor data analysis using an embedded system with a graphics processing unit
Maczkó, Adam ; Myška, Vojtěch (referee) ; Tomašov, Adrián (advisor)
The thesis deals with two main goals, namely the acceleration of data analysis and the subsequent visualization of this data. The purpose is to speed up the supplied application so that it is suitable for protecting optical infrastructures through real-time analysis of polarization state changes and visualization of its outputs. The thesis describes topics that are important in terms of accelerating computations on the graphics processor, particularly principles of parallelism, parallel programming, processes, threads, and parallel architectures. In addition, the thesis describes the capabilities of the Jetson Nano platform. The output of the thesis is an application that is capable of performing computations on the graphics processor and has a web interface for visualizing the analyzed data. The PyTorch library was used for acceleration on the graphics processor. Visualisation was achieved through the React framework in conjunction with the react-spectrogram and ApexCharts libraries.
Acoustic detectionofstarlingsthroughartificialintelligence
Zezula, B. ; Marcoň, P.
To protect the vineyards from starlings is very costly and ineffective with the available resources. In my work, I have designed a detection module which consist of four microphones, each one is directed to the cardinal point and based on the intensity of sound, the module will provide the information about the direction where the flock is located, in the vineyard that passes to the control module and scares the flocks. The detection module processes the signal in a Raspberry Pi 4 single board computer using an artificial neural network algorithm.
Radio spectrum analysis with a focus on WiFi bands using software-defined radio
Pospisil, J. ; Fujdiak, R.
This paper deals with the issue of radio spectrum analysis focused on WiFi (Wireless Fidelity) bands. The aim of the article is to approach the issue of capturing the radio spectrum and its visualization. Ways of approaching the solution of the problem are discussed, and on the basis of this comparison, attention is further focused on the use of SDR (Software Defined Radio). This device creates digitalized samples of captured radio signals and forwards them via USB to a computer, where the samples are further processed and visualized. The result is a functional program capable of visualizing this data in the form of a waterfall spectrogram. These results can also be additionally used for advanced machine analysis.
Selected Aspects of Statistical Significance Testing in Time-Frequency Analysis
Klejmová, Eva ; Kohl,, Zdeněk (referee) ; Fidrmuc, Jarko (referee) ; Poměnková, Jitka (advisor)
Přeložená dizertační práce se zabývá analýzou a posouzením kvality odhadu frekvenční a časově-frekvenční transformace dat a formulaci doporučení pro práci s metodami. Při použití těchto metod vyvstává otázka, jak vyhodnotit, které složky spektrogramu jsou statisticky významné a které nikoli. V této práci analyzujeme vlastnosti standardních testů statistické významnosti. Diskutujeme o jejich výhodách a nevýhodách s ohledem na heteroskedastický charakter dat. Na základě našich experimentů jsou v práci navrženy dva typy testovacích metod, které snižují negativní aspekty standardních testů. Práce jen zakončena vytvořením rámce pro filtrování dat pomocí námi navržených metod.
Acoustic detection of starlings through artificial intelligence
Zezula, Benjamin ; Vlachová Hutová, Eliška (referee) ; Marcoň, Petr (advisor)
To protect the vineyards from starlings is very costly and ineffective with the available resources over a period of time. In my project, I have designed a detection module that relays information about the flock location in the vineyard to the control module and thus produces scaring. I have designed two kinds of detection modules, which are compared. The first variant consists of a single directional microphone that rotates and sequentially senses the entire area of the vineyard. The second variant consists of four microphones, each one is directed to the cardinal point and based on the intensity of sound, the module will provide the information about the direction where the flock is located. Both detection modules process the signal in a Raspberry Pi 4 single board computer using an artificial neural network algorithm powered by MobileNetV2 architecture.
The Program simulating the mutes of brass instruments
Košař, Vojtěch ; Indrák, Michal (referee) ; Jirásek, Ondřej (advisor)
This Master’s thesis deals with the creation of a program that simulates an impact of sound mutes on the timbre of a trombone and a trumpet. The simulation in the Reaktor 6 environment is based on an analysis of this impact which compares the spectra and formant regions retrieved from the MATLAB environment. The analysis takes into account also the impact on harmonic overtones. Another part of this work is focusing on the theory of a trombone and a trumpet, their brief history, the parts they are consisting of and the principle of tone formation. In the Reaktor 6 environment there has been created also a sampler functioning as a virtual instrument for the trumpet and the trombon. The last part of the work deals with creating a simulation program with its structure and evaluation.
Signal Processing For Vocal Recognition Of Sturnus Vulgaris
Lázničková, Jana
This paper describes the issue of sturnus vulgaris detection in the vineyards in order toscare these animals more effectively. The analysis and classification of bird singing is difficultbecause many problems can appear. One of the problems is background noise e.g. sounds of cars,trees, and also the singing of various bird species at once. Another problem is different types of birdsongs. For example, an alarm melody, search for food, and also communication between the birdsduring a flight. This article presents a solution to one of these problems in case when only audiorecordings are available.

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