1,720,967 research outputs found
Aerodynamic measures of speech in unilateral vocal fold paralysis (UVFP) patients
No full textThis paper reports the recording and analysis of an aerodynamic database of 51 words produced by four patients with Unilateral Vocal Fold Paralysis. The vowel-fricative-vowel boundaries were manually annotated and the mean absolute oral airflow amplitude (OA), fundamental frequency (f0) and first formant intensity (IF1) were extracted from a 20 ms window in the steady state of each phone. A case study approach to analysis of phonatory behaviour for the subjects is presented.Significant differences were found between the absolute OA and IF1 for different phones. Large between subject variations in absolute measures for OA and f0 were found. Relative values calculated from the difference in these parameters between phones show consistency for subjects of the same gender. <br/
Analysis of open quotient in voiced fricative production using EGG
No full textIntroductionElectroglottography (EGG) is a common method for providing noninvasive measurements of glottal activity. The object of this study was to characterise EGG based parameters, specifically the open quotient (OQ), during fricative production, and during the phones preceding and following the fricative in a carrier phrase. With the OQ measures we aim to quantitatively establish if the relatively weak voicing during the fricative production may be differentiated from the stronger voicing of the contextual vowel. Our long term goal is to understand the mechanisms by which voicing is initiated and maintained as a guide to improving strategies for initiating and maintaining voicing in patients with laryngeal impairment such as unilateral vocal fold paralysis (UVFP) (Pinho, Jesus, & Barney, 2009).MethodsData were collected from two adult female (JG and HV) and two adult male (LJ and RS) speakers of EP. None had reported speech, language or hearing disorders, and all had normal vocal qualities. They were assessed by an experienced Speech and Language Therapist using a standardised evaluation protocol (Jesus, et al., 2009). Speakers were recorded producing 51 utterances, including 9 isolated words containing the EP voiced fricatives /v, z, Z/, in initial, medial and final word position, and the same 9 words embedded in 51 different carrier sentences, that presented a variety of consonantal (taps, laterals, stops and nasals) and vocalic (close, open front and back vowels) contexts in real EP sentences (only vowel-fricative-vowel sequences were analysed). To analyse the EGG signal we built Matlab scripts based on the open source software “MOQ interface” (Henrich, Alessandro, Doval, & Castellengo, 2004; Henrich, Gendrot, Michaud, & Tuan, 2005). We used the method “DEGG DECOM”, reported as the one that presented the best results compared to OQ measurements derived from the inverse-filtered glottal flow (Henrich, et al., 2004). These functions, developed for the singing voice (Henrich, et al., 2004), assume a quasi-periodic signal and were therefore considered to be more suitable for voicedfricative analysis. To characterise the fricatives in terms of their production mechanisms, we analysed the OQ derived from the EGG signal during the steady state of the fricative and of the adjacent vowels. The strategy used to correlate and extract information from these different modes of speech production was based on average values calculated for the OQ within phone1 (vowel), phone2 (fricative) and phone3 (vowel).ResultsWe calculated for each phone (1, 2 and 3) the average of the OQ values derived from EGGDEGG. In cases where the peaks do not stand out clearly and the OQ cannot be calculated reliably, it does not make sense to talk of an OQ at all (Henrich, et al., 2005). Therefore, zero and nonsense OQ values (e.g., fundamental frequency derived from EGG, with values equal or greater than 400Hz) were not included in subsequent analysis. For both female and male data, an increase in the OQ values during fricative production (phone2) was observed when compared to OQ values from the adjacent vowels (phone1 and phone3), as shown in Table 1.DiscussionThere was a small increase in the OQ values during the fricative, relative to that of the adjacent vowels. We can hypothesise that a more physically efficient voice is related with a decrease of the OQ value during the production of vowels (Howard, 1995). Changes observed in the EGG waveform during fricative production, thought to result from the rise in the supraglottal pressure due to a supraglottal constriction (Rothenberg & Mahshie, 1988), may be useful in a definition of weak voicing (Pinho, Jesus, & Barney, 2009). Some differences in the OQ values were also observed for different places of articulation: alveolar (/z/) fricatives showed OQ values slightly lower (59±9) than labio-dentals (/v/) and postalveolars (/Z/) (61-65±9). Further work is needed to relate these results to vocal fold mechanics.In future work we plan to extract the OQ from the inverse-filtered glottal flow (a signal we simultaneously acquired during data collection) in order to extend our study of OQ to UVFP patients where EGG cannot be reliably collected.<br/
Weak voicing in fricative production
No full textUnderstanding of the production mechanisms of voiced fricatives lags significantly behind that of other phonemic categories of speech. This paper presents a new voicing classification criterion to distinguish the voicing in fricatives from that of their contextual vowels in VCV tokens: weak vs strong voicing. The criterion is based on the oral airflow, distinguishing it from previous criteria based jointly on the acoustic and EGG signals. Aerodynamic and EGG recordings of four normal adult speakers (two females and two males), producing a speech corpus of 9 isolated words with the European Portuguese (EP) voiced fricatives /v, z, ?/ in word-initial, -medial and -final position, and the same 9 words embedded in 42 different real EP carrier sentences, were analysed. Fricatives were characterised in terms of oral airflow, fundamental frequency, first formant intensity level and glottal open quotient in absolute terms and relative to the values found in their surrounding vowels. The voicing during fricative production presented properties distinct from the voicing of the contextual vowels, leading to the development of a classification criterion based on the relative amplitude of the oscillations in the oral airflow signal. This contributes to distinguish voicing in fricatives from the modal voicing of the vowel
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
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
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