Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 15 of 15 for “"Automatische Spracherkennung"”.
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Investigations on discriminative training criteria
In this work, a framework for efficient discriminative training and modeling is developed and implemented for both small and large vocabulary continuous speech recognition. Special attention will be directed to the comparison and formalization of varying discriminative training criteria and …
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Diskriminative Modellkombination in Spracherkennungssystemen mit großem Wortschatz
In this work, the theory of Discriminative Model Combination, DMC, is developed and implemented for large vocabulary continuous speech recognition. DMC is based on a discriminative training of the free parameters of distributions belonging to the exponential family. It is independent of the …
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Statistische Auswahl von Wortabhängigkeiten in der automatischen Spracherkennung
This PhD thesis studies the overall effect of statistical language modeling on perplexity and word error rate in automatic speech recognition. A trigram language model with a standard smoothing method is extended by complex state-of-the-art language modeling techniques, including: the comparison of …
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Normalization in the acoustic feature space for improved speech recognition
In this work, normalization techniques in the acoustic feature space are studied which improve the robustness of automatic speech recognition systems. It is shown that there is a fundamental mismatch between training and test data which causes degraded recognition performance. Adaptation and …
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Quantile based histogram equalization for noise robust speech recognition
In many practical applications automatic speech recognition systems have to work in adverse acoustic environment conditions. Automatic systems are much more sensitive to the variabilities of the acoustic signal than humans. Whenever noise causes a mismatch between the distribution of the training …
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Investigations on linear transformations for speaker adaptation and normalization
This thesis deals with linear transformations at various stages of the automatic speech recognition process. In current state-of-the-art speech recognition systems linear transformations are widely used to care for a potential mismatch of the training and testing data and thus enhance the …
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Combining natural language processing systems to improve machine translation of speech
Machine translation of spoken language is a challenging task that involves several natural language processing (NLP) software modules. Human speech in one natural language has to be first automatically transcribed by a speech recognition system. Next, the transcription of the spoken utterance can …
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Acoustic feature combination for speech recognition
In this thesis, the use of multiple acoustic features of the speech signal is considered for speech recognition. The goals of this thesis are twofold: on the one hand, new acoustic features are developed, on the other hand, feature combination methods are investigated in order to find an effective …
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Modeling spontaneous speech variability for large vocabulary continuous speech recognition
In this work a number of novel techniques for improved treatment of spontaneous speech variabilities in large vocabulary automatic speech recognition are developed and evaluated on US English conversational speech and spontaneous medical dictations. Two main aspects of spontaneous speech modeling …
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Statistical computer-assisted translation
In recent years, significant improvements have been achieved in statistical machine translation (MT), but still even the best machine translation technology is far from replacing or even competing with human translators. However, an MT system helps to increase the productivity of human translators. …
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Statistical methods in natural language understanding and spoken dialogue systems
Modern automatic spoken dialogue systems cover a wide range of applications. There are systems for hotel reservations, restaurant guides, systems for travel and timetable information, as well as systems for automatic telephone-banking services. Building the different components of a spoken dialogue …
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Discriminative training and acoustic modeling for automatic speech recognition
Discriminative training has become an important means for estimating model parameters in many statistical pattern recognition tasks. While standard learning methods based on the Maximum Likelihood criterion aim at optimizing model parameters only class individually, discriminative approaches …
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A log-linear discriminative modeling framework for speech recognition
Conventional speech recognition systems are based on Gaussian hidden Markov models (HMMs).Discriminative techniques such as log-linear modeling have been investigated in speech recognition only recently. This thesis establishes a log-linear modeling framework in the context of discriminative …