1,720,962 research outputs found
PERCEPTION, PRODUCTION AND INTERACTION: A COMPREHENSIVE INVESTIGATION ON HUMAN SPEECH
No full textIn the present thesis, I focus on the three main approaches to speech research: perception, production, and interaction. Speech is a complex mechanism and it was originally considered as separated into two independent “streams”: the ventral stream for perception and the dorsal stream for production.
In the dorsal stream, a central speech processing hub is represented by Broca’s area, whose role is still under investigation. Its crucial importance for speech production has been demonstrated by means of electrical stimulation, which induces the complete arrest of ongoing speech.
During my work, I designed a machine learning algorithm that, exploiting high-gamma activity recorded from the speech-arrest area, successfully predicts speech onset in patients. The algorithm represents an important step towards the development of speech neuro-prostheses. Indeed, in patients with communication impairments, such as locked-in syndrome, decoding the intention to speak (and subsequently the covert speech itself) represents the only way to restore their connection with the external world.
Broca’s area is, as mentioned, a fundamental component of the dorsal stream, where it is putatively directly connected to the part of the motor cortex governing mouth articulators. In the other hand, past research excluded the involvement of motor regions in the ventral stream, and thus from speech perception.
In the last two decades, active listening theories became however prominent in the speech perception modelling. Several studies demonstrated indeed the activation of motor areas during listening.
In my thesis, I investigated the role of the motor system in speech perception by implementing an experiment where subjects listened to phrases without having access to the mouth kinematics. During listening, neural tracking of the speech by auditory cortical areas is enabled by means of brain entrainment to speech. Nevertheless, visual and kinematic speech-related information is also demonstrated to be tracked when available.
In this work, for the first time, neural tracking of unavailable mouth kinematics is investigated employing a novel information theoretic-based approach: the Partial Information Decomposition (PID). Through this sophisticated mathematical method, the movement of the speaker’s tongue was observed to be encoded by the motor regions, suggesting an ongoing kinematic simulation played by motor areas.
Additionally, information about a synergistic interaction between speech and tongue kinematics was present. This result could imply the existence of an integration mechanism between acoustic and kinematic inputs.
These evidences support active listening theories of speech perception, and highlight the possibility of a reconstructive top-down motor-driven mechanism that enhances speech comprehension.
Speech comprehension is crucial when people interact verbally. In order for speakers to maximize mutual understanding during verbal interaction, they rely on a mechanism called convergence. Convergence is a multi-modal process which, at an acoustic level, entails the shift of acoustic features towards a common point. However, a mathematical definition of this complex mechanism is still missing.
In order to address this scientific question, I designed a deep learning model based on Siamese architecture and Recurrent Neural Networks. The proposed model is tuned to learn temporal dependencies and produce a similarity index between couples of speech stream.
When tested in a sentence independence scenario, the Siamese model succeeded in computing the voices distance. In contrast, the performance in speaker independence has still to be enhanced
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Variations on the Author
Get PDF“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
Get PDFWe 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
The ART of Conversation: Measuring Phonetic Convergence and Deliberate Imitation in L2-Speech with a Siamese RNN
Get PDFPhonetic convergence describes the automatic and unconscious speech
adaptation of two interlocutors in a conversation. This paper proposes a
Siamese recurrent neural network (RNN) architecture to measure the convergence
of the holistic spectral characteristics of speech sounds in an L2-L2
interaction. We extend an alternating reading task (the ART) dataset by adding
20 native Slovak L2 English speakers. We train and test the Siamese RNN model
to measure phonetic convergence of L2 English speech from three different
native language groups: Italian (9 dyads), French (10 dyads) and Slovak (10
dyads). Our results indicate that the Siamese RNN model effectively captures
the dynamics of phonetic convergence and the speaker's imitation ability.
Moreover, this text-independent model is scalable and capable of handling
L1-induced speaker variability.Comment: Accepted at INTERSPEECH 202
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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