Survey of Noise Estimation Algorithms for Speech Enhancement Using Spectral Subtraction

Speech enhancement means speech improvement. Actually the speech enhancement is performed by using various techniques and different algorithms. Over the past several years there has been attention focused on the problem of enhancement of speech degraded by additive background noise. For many applications background suppression is required. The spectral - subtractive algorithm is one of the first algorithm proposed for additive background noise and it has gone through many modifications with time. For spectral subtraction method noise estimation is important for that there are various noise estimation algorithms. All these noise estimation algorithms are important for removing background noise

Identification of persons via voice imprint

Tato práce se zabývá textově závislým rozpoznáváním řečníků v systémech, kde existuje pouze omezené množství trénovacích vzorků. Pro účel rozpoznávání je navržen otisk hlasu založený na různých příznacích (např. MFCC, PLP, ACW atd.). Na začátku práce je zmíněn způsob vytváření řečového signálu. Některé charakteristiky řeči, důležité pro rozpoznávání řečníků, jsou rovněž zmíněny. Další část práce se zabývá analýzou řečového signálu. Je zde zmíněno předzpracování a také metody extrakce příznaků. Následující část popisuje proces rozpoznávání řečníků a zmiňuje způsoby ohodnocení používaných metod: identifikace a verifikace řečníků. Poslední teoreticky založená část práce se zabývá klasifikátory vhodnými pro textově závislé rozpoznávání. Jsou zmíněny klasifikátory založené na zlomkových vzdálenostech, dynamickém borcení časové osy, vyrovnávání rozptylu a vektorové kvantizaci. Tato práce pokračuje návrhem a realizací systému, který hodnotí všechny zmíněné klasifikátory pro otisk hlasu založený na různých příznacích.This work deals with the text-dependent speaker recognition in systems, where just a few training samples exist. For the purpose of this recognition, the voice imprint based on different features (e.g. MFCC, PLP, ACW etc.) is proposed. At the beginning, there is described the way, how the speech signal is produced. Some speech characteristics important for speaker recognition are also mentioned. The next part of work deals with the speech signal analysis. There is mentioned the preprocessing and also the feature extraction methods. The following part describes the process of speaker recognition and mentions the evaluation of the used methods: speaker identification and verification. Last theoretically based part of work deals with the classifiers which are suitable for the text-dependent recognition. The classifiers based on fractional distances, dynamic time warping, dispersion matching and vector quantization are mentioned. This work continues by design and realization of system, which evaluates all described classifiers for voice imprint based on different features.

Collective instability and physics of the anomalous Doppler resonance in fusion plasmas

The anomalous Doppler instability (ADI) is a key relaxation mechanism for suprathermal electrons in magnetic confinement fusion (MCF) plasmas. The ADI involves a shift from parallel to perpendicular electron motion, accompanied by the excitation of waves at frequency and wavenumber satisfying the anomalous Doppler resonance condition. In this thesis we split effort between studying the physics of the anomalous Doppler resonance and developing a new code to address linear calculations in magnetized plasmas characterized by arbitrary gyrotropic velocity distribution functions. This fully relativistic code is more general than the analytical linear theory which has been performed previously. This code is benchmarked against many problems in plasma physics. We perform 2D3V particle-in-cell (PIC) simulations of the ADI for an energetic electron tail oriented in the magnetic field direction. For the first time we verify, via fully kinetic simulation, that the long standing conjecture, that it is possible for the ADI to self consistently drive a positive slope in the parallel electron velocity distribution, is correct. We show that the presence of this positive slope excites waves in a separate region of frequency and wavevector space to the ADI. We show that the simulated linear and quasilinear stages of instability demonstrate strong agreement with the linear solver which we have constructed. We also show that the addition of a second simulated spatial dimension is necessary to capture nonlinear three-wave coupling which can be driven by the ADI. The location of this three-wave triad, which has not previously been explored, is consistent with what would be predicted by the wave matching condition and a cold plasma model

Air Force Institute of Technology Research Report 1997

This report summarizes the research activities of the Air Force Institute of Technology\u27s Graduate School of Engineering and the Graduate School of Logistics and Acquisition Management. It describes research interests and faculty expertise; list student theses/dissertations; identifies research sponsors and contributions; and outlines the procedure for contacting either school

Abstracts on Radio Direction Finding (1899 - 1995)

The files on this record represent the various databases that originally composed the CD-ROM issue of "Abstracts on Radio Direction Finding" database, which is now part of the Dudley Knox Library's Abstracts and Selected Full Text Documents on Radio Direction Finding (1899 - 1995) Collection. (See Calhoun record https://calhoun.nps.edu/handle/10945/57364 for further information on this collection and the bibliography). Due to issues of technological obsolescence preventing current and future audiences from accessing the bibliography, DKL exported and converted into the three files on this record the various databases contained in the CD-ROM. The contents of these files are: 1) RDFA_CompleteBibliography_xls.zip [RDFA_CompleteBibliography.xls: Metadata for the complete bibliography, in Excel 97-2003 Workbook format; RDFA_Glossary.xls: Glossary of terms, in Excel 97-2003 Workbookformat; RDFA_Biographies.xls: Biographies of leading figures, in Excel 97-2003 Workbook format]; 2) RDFA_CompleteBibliography_csv.zip [RDFA_CompleteBibliography.TXT: Metadata for the complete bibliography, in CSV format; RDFA_Glossary.TXT: Glossary of terms, in CSV format; RDFA_Biographies.TXT: Biographies of leading figures, in CSV format]; 3) RDFA_CompleteBibliography.pdf: A human readable display of the bibliographic data, as a means of double-checking any possible deviations due to conversion

Internet and Biometric Web Based Business Management Decision Support

Internet and Biometric Web Based Business Management Decision Support MICROBE MOOC material prepared under IO1/A5 Development of the MICROBE personalized MOOCs content and teaching materials Prepared by: A. Kaklauskas, A. Banaitis, I. Ubarte Vilnius Gediminas Technical University, Lithuania Project No: 2020-1-LT01-KA203-07810