1,954 research outputs found

    The Role of Prosodic Stress and Speech Perturbation on the Temporal Synchronization of Speech and Deictic Gestures

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    Gestures and speech converge during spoken language production. Although the temporal relationship of gestures and speech is thought to depend upon factors such as prosodic stress and word onset, the effects of controlled alterations in the speech signal upon the degree of synchrony between manual gestures and speech is uncertain. Thus, the precise nature of the interactive mechanism of speech-gesture production, or lack thereof, is not agreed upon or even frequently postulated. In Experiment 1, syllable position and contrastive stress were manipulated during sentence production to investigate the synchronization of speech and pointing gestures. An additional aim of Experiment 2 was to investigate the temporal relationship of speech and pointing gestures when speech is perturbed with delayed auditory feedback (DAF). Comparisons between the time of gesture apex and vowel midpoint (GA-VM) for each of the conditions were made for both Experiment 1 and Experiment 2. Additional comparisons of the interval between gesture launch midpoint to vowel midpoint (GLM-VM), total gesture time, gesture launch time, and gesture return time were made for Experiment 2. The results for the first experiment indicated that gestures were more synchronized with first position syllables and neutral syllables as measured GA-VM intervals. The first position syllable effect was also found in the second experiment. However, the results from Experiment 2 supported an effect of contrastive pitch effect. GLM-VM was shorter for first position targets and accented syllables. In addition, gesture launch times and total gesture times were longer for contrastive pitch accented syllables, especially when in the second position of words. Contrary to the predictions, significantly longer GA-VM and GLM-VM intervals were observed when individuals responded under provided delayed auditory feedback (DAF). Vowel and sentence durations increased both with (DAF) and when a contrastive accented syllable was produced. Vowels were longest for accented, second position syllables. These findings provide evidence that the timing of gesture is adjusted based upon manipulations of the speech stream. A potential mechanism of entrainment of the speech and gesture system is offered as an explanation for the observed effects

    Speech Communication

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    Contains reports on five research projects.U. S. Air Force (Electronic Systems Division) under Contract AF 19(628)-3325National Science Foundation (Grant GP-Z495)National Institutes of Health (Grant MH-04737-04)National Institutes of Health (Grant NB-0433Z-02)National Aeronautics and Space Administration (Grant NsG-496

    Limits of performance of chirped- pulse phase-sensitive OTDR

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    Distributed acoustic sensing is an emerging field of research which aims to develop methods capable of using a single optical fiber as a long, dense, and high-sensitivity sensor array. Currently, the most promising implementations measure the interference of Rayleigh backscattered light, obtained by probing the fiber with light from a source of high coherence. These methods are known as Phase-sensitive Optical Time-Domain Reflectometers (φOTDR), and are currently undergoing a period of active research and development, both academically and industrially. One of its variants, known as the Chirped-Pulse φOTDR (CP-φOTDR), was developed in 2016. This technique has proven to be remarkably sensitive to strain and temperature, with an attractively simple implementation. In this thesis, we delve into the intricacies of this technique, probing its fundamental limits and addressing current limitations. We discuss the implications of estimation on the performance statistics, the impact of different noise sources and the origin of cross-talk between independent measured positions. In doing so, we also propose methods to reach the current fundamental limitations, and overcome the upper bound of measurable perturbations. We then demonstrate new potential applications of the technique: in seismology, by exploiting the high spatial density of measurements for array signal processing; in the fast characterization of linear birefringence in standard single-mode fibers; and on the measurement of sound pressure waves, by using a special flat cable structure to embed the fiber under test. Finally, we summarize and comment on the aforementioned achievements, proposing some open lines of research that may originate from these results.Distributed acoustic sensing is an emerging field of research which aims to develop methods capable of using a single optical fiber as a long, dense, and highsensitivity sensor array. Currently, the most promising implementations measure the interference of Rayleigh backscattered light, obtained by probing the fiber with light from a source of high coherence. These methods are known as Phase-sensitive Optical Time-Domain Reflectometers (φOTDR), and are currently undergoing a period of active research and development, both academically and industrially. One of its variants, known as the Chirped- Pulse φOTDR (CP-φOTDR), was developed in 2016. This technique has proven to be remarkably sensitive to strain and temperature, with an attractively simple implementation. In this thesis, we delve into the intricacies of this technique, probing its fundamental limits and addressing current limitations. We discuss the implications of estimation on the performance statistics, the impact of different noise sources and the origin of cross-talk between independent measured positions. In doing so, we also propose methods to reach the current fundamental limitations, and overcome the upper bound of measurable perturbations. We then demonstrate new potential applications of the technique: in seismology, by exploiting the high spatial density of measurements for array signal processing; in the fast characterization of linear birefringence in standard single-mode fibers; and on the measurement of sound pressure waves, by using a special flat cable structure to embed the fiber under test. Finally, we summarize and comment on the aforementioned achievements, proposing some open lines of research that may originate from these results

    Pattern Recognition of Power System Voltage Stability using Statistical and Algorithmic Methods

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    In recent years, power demands around the world and particularly in North America increased rapidly due to increase in customer’s demand, while the development in transmission system is rather slow. This stresses the present transmission system and voltage stability becomes an important issue in this regard. Pattern recognition in conjunction with voltage stability analysis could be an effective tool to solve this problem In this thesis, a methodology to detect the voltage stability ahead of time is presented. Dynamic simulation software PSS/E is used to simulate voltage stable and unstable cases, these cases are used to train and test the pattern recognition algorithms. Statistical and algorithmic pattern recognition methods are used. The proposed method is tested on IEEE 39 bus system. Finally, the pattern recognition models to predict the voltage stability of the system are developed

    Pattern Recognition of Power System Voltage Stability using Statistical and Algorithmic Methods

    Get PDF
    In recent years, power demands around the world and particularly in North America increased rapidly due to increase in customer’s demand, while the development in transmission system is rather slow. This stresses the present transmission system and voltage stability becomes an important issue in this regard. Pattern recognition in conjunction with voltage stability analysis could be an effective tool to solve this problem In this thesis, a methodology to detect the voltage stability ahead of time is presented. Dynamic simulation software PSS/E is used to simulate voltage stable and unstable cases, these cases are used to train and test the pattern recognition algorithms. Statistical and algorithmic pattern recognition methods are used. The proposed method is tested on IEEE 39 bus system. Finally, the pattern recognition models to predict the voltage stability of the system are developed

    Nondestructive Testing (NDT)

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    The aim of this book is to collect the newest contributions by eminent authors in the field of NDT-SHM, both at the material and structure scale. It therefore provides novel insight at experimental and numerical levels on the application of NDT to a wide variety of materials (concrete, steel, masonry, composites, etc.) in the field of Civil Engineering and Architecture

    Nonlinear feature based classification of speech under stress

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    LaDIVA: A neurocomputational model providing laryngeal motor control for speech acquisition and production

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    Many voice disorders are the result of intricate neural and/or biomechanical impairments that are poorly understood. The limited knowledge of their etiological and pathophysiological mechanisms hampers effective clinical management. Behavioral studies have been used concurrently with computational models to better understand typical and pathological laryngeal motor control. Thus far, however, a unified computational framework that quantitatively integrates physiologically relevant models of phonation with the neural control of speech has not been developed. Here, we introduce LaDIVA, a novel neurocomputational model with physiologically based laryngeal motor control. We combined the DIVA model (an established neural network model of speech motor control) with the extended body-cover model (a physics-based vocal fold model). The resulting integrated model, LaDIVA, was validated by comparing its model simulations with behavioral responses to perturbations of auditory vocal fundamental frequency (fo) feedback in adults with typical speech. LaDIVA demonstrated capability to simulate different modes of laryngeal motor control, ranging from short-term (i.e., reflexive) and long-term (i.e., adaptive) auditory feedback paradigms, to generating prosodic contours in speech. Simulations showed that LaDIVA’s laryngeal motor control displays properties of motor equivalence, i.e., LaDIVA could robustly generate compensatory responses to reflexive vocal fo perturbations with varying initial laryngeal muscle activation levels leading to the same output. The model can also generate prosodic contours for studying laryngeal motor control in running speech. LaDIVA can expand the understanding of the physiology of human phonation to enable, for the first time, the investigation of causal effects of neural motor control in the fine structure of the vocal signal.Fil: Weerathunge, Hasini R.. Boston University; Estados UnidosFil: Alzamendi, Gabriel Alejandro. Universidad Nacional de Entre Ríos. Instituto de Investigación y Desarrollo en Bioingeniería y Bioinformática - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigación y Desarrollo en Bioingeniería y Bioinformática; ArgentinaFil: Cler, Gabriel J.. University of Washington; Estados UnidosFil: Guenther, Frank H.. Boston University; Estados UnidosFil: Stepp, Cara E.. Boston University; Estados UnidosFil: Zañartu, Matías. Universidad Técnica Federico Santa María; Chil

    The effect of perceptual training on the learning of english vowels by brazilian portuguese speakers

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    Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Comunicação e Expressão. Programa de Pós-Graduação em Letras/Inglês e Literatura Correspondente.Pesquisas recentes mostram que o treinamento perceptual é uma ferramenta eficaz para melhorar a habilidade de perceber certos sons não-nativos de aprendizes de uma L2, especialmente quando esse treinamento é feito com a manipulação das pistas acústico-perceptuais. O presente estudo investigou o efeito do treinamento perceptual no aprendizado das vogais do inglês /i/, /I/, /E/, /Q/, /U/ e /u/, cuja percepção deficiente pode causar problemas de compreensão. Os objetivos específicos incluem investigar (i) o efeito do treinamento com estímulo artificial, (ii) a generalização do novo conhecimento para novos contextos e novos falantes, (iii) a transferência da melhora na percepção auditiva para produção oral e (iv) os efeitos de longo prazo. O treinamento das vogais foi ministrado durante o período de três semanas para 29 aprendizes brasileiros distribuídos em dois grupos: 15 treinaram com estímulo natural (grupo NatS) e 14 com estímulo sintetizado (grupo SynS). O estímulo sintetizado consistiu em elocuções com pistas espectrais enfatizadas e sem variação de duração e foram geradas por computador, enquanto que o estímulo natural foi gravado por falantes nativos de inglês americano. Os resultados apontam para uma melhora significativa dos grupos experimentais após o treinamento, sendo que houve uma melhora maior no grupo SynS do que no grupo NatS. Considerando que o treinamento ministrado para o grupo SynS consistiu apenas de estímulos sintetizados e que os testes incluíam apenas estímulos naturais, esse resultado também sugere que houve uma transferência do conhecimento adquirido com estímulo artificial para estímulos produzidos naturalmente. A melhora na performance dos alunos também foi mantida durante um mês após o final do treinamento. Estes resultados mostram que o treinamento perceptual pode servir como uma ferramenta eficaz para professores auxiliarem seus alunos a superar dificuldades perceptuais, evitando possíveis mal entendidos. Recent research has shown perceptual training to be an effective tool for improving L2 learners# ability to perceive certain non-native sounds, especially when done with enhanced acoustic-perceptual cues. This study investigates the effect of perceptual training on the learning of the English vowels /i/, /I/, /E/, /Q/, /U/ and /u/, whose misperception can potentially cause comprehension problems. Secondary objectives include (i) the effect of training with enhanced stimuli, (ii) generalization of the acquired knowledge to new contexts and speakers, (iii) transfer of the perceptual improvement to the production domain, and (iv) long-term effects. The training on these vowels was given over a three-week period to twenty-nine Brazilian EFL learners, who were distributed within two groups: fifteen trained with natural stimuli (NatS group) and fourteen with synthesized stimuli (SynS group). The synthesized stimuli consisted of computer-generated utterances with enhanced spectral cues and no variation in duration, whereas the natural stimuli were recorded normally by native speakers of American English. Results show that the experimental groups improved significantly after training, and there was more improvement in the SynS group than in the NatS group. Considering that the training given the SynS group involved only synthesized stimuli and the tests involved only natural stimuli, this finding suggests also that the knowledge acquired with artificially enhanced stimuli is transferred to stimuli produced naturally. The improvement was also maintained one month after the training was over. These findings support the claim that perceptual training may serve as an effective tool for teachers to help learners overcome potential perceptual difficulties, and thus prevent potential miscomprehension

    Speech Communication

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    Contains reports on four research projects.National Institutes of Health (Grant 5 ROl NB04332-08)U.S. Air Force Cambridge Research Laboratories, Office of Aerospace Research, under Contract F19628-69-C-004
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