1,720,999 research outputs found
Ergodic Hidden Markov models for speech synthesis
No full textApplications of Ergodic Hidden Markov Models in speech synthesis are presented. EHMM using autoregressive gaussian continuous densities as state observation densities are defined. The ability of such model to represent phonotactical constraints of the language is investigated through the analysis of the transition matrix structure and with some ergodic speech synthesis experiments. Applications of EHMM models in speech synthesis units segmentation and phone-like models statistical units representation are presented
Speech segmentation and classification using higher order moments
No full textA new criterion for speech segmentation based on higher order moments is presented. It is shown that simple estimates of third and fourth order cumulants can provide useful cues for speech segmentation and classification. In fact, the analysis of the cumulants behaviour seems well suited for discriminating voiced, unvoiced and transient sounds. Moreover, the estimated quantities give some indications about the information content of segments of speech. This permit the experimentation of a coding scheme for the speech signal, which has yet been experimented in image coding, founded on a perceptually - based conjectur
Some experiments on the HMM Structure Inference
No full textA method for finding a maximally representative graph structure for the acoustic events associated to linguistic units is presented. The method consists in a three-stage Dynamic Programming technique, applied to sets of acoustic label sequences collected for linguistic units, and obtained by Viterbi alignment of the incoming speech against the states of an Ergodic HMM. These sequences are first aligned in between them, and then collapsed into a reduced trellis. The trellis is then repeatedly explored by a second DP procedure which selects a list of the more probable sequences. Finally, a third algorithm is utilized for dynamically build ah HMM network
Phonetic Units and Phonotactical Structure Inference by EHMM
No full textA general model for the representation of the spoken language is proposed. It is based on Ergodic Hidden Markov Models and allows the introduction of linguistically consistent sub-phonetic units, accounting for the stationary and transitional behaviour of the spoken message. The main characteristics of the proposed model are analysed, and some applications to speech recognition and coding are presented
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Experimental analysis of fixed multipulse excitation patterns in PC synthesis
No full textThe text-to-speech systems based on the concatenation of acoustic units codified with the linear prediction method, require that the sysìnthesis filter is excited by an artificial source signal. In the case of voiced speech sounds, the periodic source is represented by pulses that are spaced by the required period. The signal reproduced using this source is characterized by a fuzzy and tense quality. A very effective method used to reproduce with a high quality the speech signal using linear prediction is the multi-pulse method. It has been experimentally shown that the use of fixed multipulse patterns chosen from the analysis of the voice of a speaker determines a relevant improvement of the synthetic signal, also if these patterns are used to reproduce other realizations of the speaker, or even of other speakers. This result is not easily explainable, because the data obtained in the perception tests performed on signal synthetized with sources of particular spectral characteristics of amplitude and phase show that the amplitude of the harmonics of the sources is critical parameter for the correct reproduction. It is moreover important that these components reproduce a natural distribution of the phase that is variable in function of frequency and time. The use of fixed multi-pulse sequences does not however satisfy these conditions. In this paper an hypothesis about the reasons that determine the improvement obtained using multipulse patterns is verified and the characteristics of the implementation of a real-time text-to-speech system using a multipulse source are briefly considered
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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