The development of clear speech strategies in 9-14 year olds

This study investigated the development of global clear speech strategies of child talkers. Two groups of 20 talkers aged 9-10 (children) and 13-14 (teens) were recorded in pairs while they carried out spot the difference picture tasks, either hearing each other normally (NB condition) or with one talker hearing the other via a three-channel noise vocoder (VOC condition). Acoustic-phonetic analyses focused on the talker having to overcome the communication barrier. Data were compared to those for 20 of the adults in Hazan and Baker (2011) [J.Acoust.Soc, Am, 130, 2139-2152]. The three age groups did not differ in task transaction time for NB, but children took significantly longer to complete the task in VOC than teens or adults who took equally long. Children spoke at a slower speech rate overall than teens, while teens and adults did not differ; all groups significantly reduced their speech rate in VOC relative to NB. Adults hyperarticulated vowels in VOC but children and teens showed only minor adaptations. These results suggest that although 9-10 year olds use some strategies to clarify their speech in difficult conditions, other strategies continue to develop into late adolescence

Is prosodic production driven by lexical development ? Longitudinal evidence from babble and words

This study investigated the relation between lexical development and the production of prosodic prominence in disyllabic babble and words. Monthly recordings from nine typically developing Belgian-Dutch-speaking infants were analysed from the onset of babbling until a cumulative vocabulary of 200 words was reached. The differentiation between the two syllables of isolated disyllabic utterances was computed for f0, intensity and duration measurements. Results showed that the ambient trochaic pattern emerged in babble, but became enhanced in words. Words showed more prosodic differentiation in terms of f0 and intensity and a more even duration ratio. Age or vocabulary size did not predict the expansion of f0 or intensity in words, whereas vocabulary size was related to the production of more even-timed syllables. The findings are discussed in terms of lexicalist accounts of phonetic development and a potential phonetic highlighting function of first words

Understanding Link Dynamics in Wireless Sensor Networks with Dynamically Steerable Directional Antennas

Abstract. By radiating the power in the direction of choice, electronicallyswitched directional (ESD) antennas can reduce network contention and avoid packet loss. There exists some ESD antennas for wireless sensor networks, but so far researchers have mainly evaluated their directionality. There are no studies regarding the link dynamics of ESD antennas, in particular not for indoor deployments and other scenarios where nodes are not necessarily in line of sight. Our long-term experiments confirm that previous findings that have demonstrated the dependence of angleof-arrival on channel frequency also hold for directional transmissions with ESD antennas. This is important for the design of protocols for wireless sensor networks with ESD antennas: the best antenna direction, i.e., the direction that leads to the highest packet reception rate and signal strength at the receiver, is not stable but varies over time and with the selected IEEE 802.15.4 channel. As this requires protocols to incorporate some form of adaptation, we present an intentionally simple and yet efficient mechanism for selecting the best antenna direction at run-time with an energy overhead below 2 % compared to standard omni-directional transmissions.

A Comprehensive Optimization of Ultrasound\u2010Assisted Extraction for Lycopene Recovery from Tomato Waste and Encapsulation by Spray Drying

This study aimed to extract bioactive compounds from tomato waste through ultrasoundassisted extraction (UAE), using ethanol as solvent. Process optimization was carried out by a central composite design of 33 runs for response surface modelling, simultaneously analyzing the effect of temperature (T), time (t), volume (V), liquid\u2010to\u2010solid ratio (L/S), amplitude (A), the pulser duration (on), and their interaction. The best conditions found by the desirability method (T = 65 \ub0C, t = 20 min, L/S = 72 mL/g, A = 65%, on = 33 s, V = 90 mL) were experimentally verified, leading to the production of an extract with interesting properties (total carotenoids of 1408 \ub114 \u3bcglycopene equivalents/g, lycopene yield of 1536 \ub1 53 \u3bcg/g, 36.1 \ub1 0.9 \u3bcgtrolox equivalents/g as antiradical power). Due to the instability of lycopene, the extract encapsulation by spray drying was undertaken using inulin and maltodextrins as coating agents. The evaluation of wall material composition provided high product recovery (73%), a high content of encapsulated compared to superficial lycopene (15.3 \ub1 2.9 and 0.30 \ub1 0.02 \u3bcg/g), and a product with good water solubility. The novelty of this work concerned the simultaneous study of the effect and interdependences of the UAE parameters, and the use of inulin to enhance the properties of microparticles

A field study on human factor and safety performances in a downstream oil industry

afety culture and awareness by workers are pivotal tools for the implementation of systematic procedures aiming to risk mitigation in the process industry. The evaluation of human factors on safety performance can reveal unsafe attitudes and failures in training, supervision and management, whose correction greatly contribute to the enhancement of safety program. In this work, the role of human factors in an oil industry was studied by the collection of field data through a structured questionnaire filled by shift, daily and outsourced workers. A deep investigation on the variables involved in the process was carried out, firstly quantifying three conceptual key dimensions (individual, human resource management, equipment and technology) and then analyzing data by means of Response Surface Methodology (RSM), to identify the statistical significant factors and the overall level of safety awareness, behaviour and risk perception of the respondents

Accent attribution in speakers with Foreign Accent Syndrome

Purpose: The main aim of this experiment was to establish the extent to which the impression of foreignness in speakers with Foreign Accent Syndrome (FAS) is in any way comparable to the impression of foreignness in speakers with a real foreign accent. Method: Three groups of listeners attributed accents to conversational speech samples of 5 FAS speakers which were embedded amongst those of 5 speakers with a real foreign accent and 5 native speaker controls. The listener groups differed in their familiarity with foreign accented speech and speech pathology. Results: The findings indicate that listeners’ perceptual reactions to the three groups of speakers are essentially different at all levels of analysis. The native speaker controls are unequivocally considered as native speakers of Dutch while the speakers with a real foreign accent are very reliably assessed as non-native speakers. The speakers with Foreign Accent Syndrome, however, are in some sense perceived as foreign and in some sense as native by listeners, but not as foreign as speakers with a real foreign accent nor as native as real native speakers. This result may be accounted for in terms of the trigger support model of foreign accent perception. Conclusions: The findings of the experiment is consistent with the idea that the very nature of the foreign accent in different in both groups of speakers, although it cannot be fully excluded that the perceived foreignness in the two groups is one of degree

The impact of variation in phoneme category structure on consonant intelligibility

Newman et al. [J. Acoustic. Soc. Am, 109, 1181-1196 (2001)] suggested that phoneme identification accuracy and speed for a given talker was affected by the degree of variability in their production of phoneme categories. This study investigates how intra-talker variability in the production of two phoneme contrasts varies with age and gender, and how this variability affects perception. Multiple iterations of tokens differing in initial consonants (/s/-/ʃ/, /p/-/b/) were collected via picture elicitation from 40 adults and 31 children aged 11 to 14; measures of within-category dispersion, between-category distance, overlap and discriminability were obtained. While females produced more discriminable categories than males, children produced farther yet more dispersed - and thus similarly discriminable - categories than adults. Variability was contrast-specific rather than a general talker characteristic. Tokens with initial /s/-/ʃ/ from pairs of adult and child talkers varying in between-category distance or overlap were presented for identification. The presence of overlap had a greater effect on identification accuracy and speed than between-category distance, with strongest effects for adult speakers, but reaction time correlated most highly with within category dispersion. These data suggest that talkers who are less consistent in their speech production may be perceived less clearly than more internally-consistent talkers