@phdthesis{MariHilario2004, author = {Mar{\´i} Hilario, Joan}, title = {Discriminative connectionist approaches for automatic speech recognition in cars}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-000000649}, school = {BTU Cottbus - Senftenberg}, year = {2004}, abstract = {The first part of this thesis is devoted to the evaluation of approaches which exploit the inherent redundancy of the speech signal to improve the noise robustness. On the basis of this evaluation on the AURORA 2000 database, we further study in detail two of the evaluated approaches. The first of these approaches is the hybrid RBF/HMM approach, which is an attempt to combine the superior classification performance of radial basis functions (RBFs) with the ability of HMMs to model time variation. The second approach is using neural networks to non-linearly reduce the dimensionality of large feature vectors including context frames. We propose the use of different MLP topologies for that purpose. Experiments on the AURORA 2000 database reveal that the performance of the first approach is similar to the performance of systems based on SCHMMs. The second approach cannot outperform the performance of linear discriminant analysis (LDA) on a database recorded in real car environments, but it is on average significantly better than LDA on the AURORA 2000 database.}, subject = {Kraftfahrzeuginnenraum; Automatische Spracherkennung; Sprachqualit{\"a}t; Sprachsignal; St{\"o}rsignal; Redundanzanalyse; Neuronales Netz; Speech recognition; Noise robustness; Evaluation; AURORA; Connectionist}, language = {en} } @phdthesis{Wersenyi2002, author = {Wers{\´e}nyi, Gy{\"o}rgy}, title = {HRTFs in human localization: measurement, spectral evaluation and practical use in virtual audio environment}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-000000234}, school = {BTU Cottbus - Senftenberg}, year = {2002}, abstract = {Many recent works have focused on hearing modeling. In human localization play the outer ears and the shape of the human body a significant role. Little modifications of the acoustical environment near to the listeners' head have significant effects on the transfer functions (HRTFs). This work analyses the transmission of the directional information and contributes to the suggestions of the physiological hypotheses based on the role of the HRTFs. Microphones are placed at the eardrums of a dummy-head, and accurate measurements will be performed. First, a good quality binaural playback system is tested using equalized headphones and HRTF filtering in order to find well-known errors and the localization blur. The second part introduces an accurate dummy-head measurement system with increased precision, signal-to-noise ratio and reproducibility. Finally, the HRTFs in the frequency domain and the effect of the acoustical environment near to the head will be evaluated (effects of the "everyday objects" near to the head). In the discussion section we try to specify the quality levels of existing binaural systems and the role of the HRTFs in virtual and non-virtual environments during the decoding of the acoustical information.}, subject = {Tonstudiotechnik; Binaurales H{\"o}ren; Richtungsh{\"o}ren; Raumakustik; Signal-Rausch-Abstand; {\"U}bertragungsfunktion; HRTF; Acoustic; Dummy-head; Headphone; Localisation}, language = {en} } @phdthesis{Heuer2006, author = {Heuer, Henning}, title = {Auf Tantal-Silizium basierende Diffusionsbarrieren zur Verkapselung funktionaler Bauelemente}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus-10}, school = {BTU Cottbus - Senftenberg}, year = {2006}, abstract = {Flexible D{\"u}nnschichtsolarzellen erfordern eine ebenfalls flexible Verkapselung, um das Absorbermaterial (z.B. Kupfer - Indium - 2 Selenide (CIS) vor der Eindiffusion von Feuchtigkeit und anderen Umwelteinfl{\"u}ssen zu sch{\"u}tzen. Diffusionsbarrieren auf Tantal-Silizium Basis sind z. Z. bevorzugtes Material um die Kupferdiffusion in modernen Halbleiterbauelementen zu verhindern. In dieser Arbeit werden Tantal-Silizium-Stickstoff und Tantal-Silizium-Sauerstoff Schichten f{\"u}r die Verkapselung von zuk{\"u}nftigen flexiblen D{\"u}nnschichtsolarzellen untersucht und optimiert. CIS-Solarmodule wurden mit d{\"u}nnen, auf Tantal basierten Barrieren beschichtet. Die Barrierewirkung der Verkapselung wurde untersucht, indem die Ver{\"a}nderungen des Wirkungsgrades d{\"u}nnschichtverkapselter Module w{\"a}hrend eines 1000-st{\"u}ndigen beschleunigten Alterungstest bestimmt wurden. Eine wesentliche Verbesserung der Barrierewirkung gegen die Eindiffusion von Feuchtigkeit wurde mit einer reaktiv gesputterten Doppelschicht aus 250 nm Ta-Si-O und 15 nm Ta- Si-N erreicht. Dieses Doppelschichtsystem erreicht bei einer Dicke von 265 nm eine vergleichbare Schutzwirkung wie eine ca. 5 µm dicke Schicht aus SiO2.}, subject = {Tantal; Solarzelle; Verkapselung; Diffusionsbarrieren; Flexible Solarzellen; Tantal-Silizium; D{\"u}nne Schichten; Tantal; Solar cell; Encapsulation}, language = {de} }