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The world is filled with richly diverse sounds which we are able to perceptually distinguish using a variety of properties. One of these properties is the amplitude envelope, or the intensity of a sound over time. While it is common in the real world for sounds to have time-varying amplitude envelopes, the majority of sounds used in perceptual research have time-invariant or unspecified amplitude envelopes. The aim of the present thesis is twofold. Because many of the studies using time-invariant or undefined envelopes make use of very short sounds (below 100 msec), the first experiment aimed to determine the duration required for discriminating among three different envelopes: flat (invariant), ramped (increasing in intensity over time), and damped (decreasing in intensity over time). In Experiment 1, participants took part in a 2-alternative forced choice, psychophysical staircase paradigm in which they indicated which of two envelopes they thought they were listening to. Results showed that, when telling ramped tones apart from either flat or damped tones, participants showed discrimination thresholds below 50 msec, while they had thresholds of approximately 75-80 msec when differentiating flat from damped tones. Because amplitude envelope has been shown to impact audiovisual integration and the perceptual system is sensitive to interaural envelope differences when localizing sounds, the second experiment aimed to determine whether amplitude envelope could modulate the visual bias present in spatial ventriloquism, an audiovisual illusion where the perceived location of a sound is influenced by the location of a visual stimulus. In Experiment 2, participants performed a psychophysical staircase task which measured their accuracy in localizing sounds with flat and damped envelopes, with or without a simultaneous flash on the screen in front of them. Results showed that, at durations above the envelope discrimination thresholds found in Experiment 1 (83 msec), there was no visual bias on perceived location of the sound, while the bias was present at a duration below this threshold (16 msec). Together, these results add to the mounting evidence suggesting that amplitude envelope has profound and varied effects on our perception of sounds, and is an important property to consider when designing experiments. / Thesis / Master of Science (MSc)

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Orientador: Nuno Cesar Pereira de Abreu / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Artes / Made available in DSpace on 2018-08-26T23:27:12Z (GMT). No. of bitstreams: 1 Miranda_FabiannaMariaWhonrath_D.pdf: 106462815 bytes, checksum: 451402fcb413b650b69fe0c23c38582e (MD5) Previous issue date: 2015 / Resumo: O presente trabalho é resultado das reflexões e análises advindas da experiência docente da pesquisadora com o ensino de produção de vídeo na 1a série do Ensino Médio por um período de quatro anos em uma escola da rede particular na cidade de Campinas ¿ SP. O objetivo foi o de avaliar aspectos da percepção dos alunos acerca do próprio aprendizado a partir da descrição dos procedimentos realizados em sala de aula e dos seus resultados. O curso de "Cinema e produção de vídeo", instituído na escola estudada como disciplina regular do currículo de Artes na 1a série do Ensino Médio em 2009, foi pensado para favorecer, nos estudantes, o desenvolvimento de habilidades e competências relacionadas às exigências de uma sociedade em que o audiovisual passou a ocupar um espaço de destaque nas relações interpessoais como ferramenta de comunicação. A escolha pelo método fenomenológico a partir do relato de experiências dos alunos pretende, portanto, tratar com certa precisão uma realidade imprecisa e dinâmica a qual demandará, cada vez mais, processos de aprendizagem variados e, também, em contínua evolução. A discussão acerca da importância da desconstrução de estratégicas pedagógicas antigas e, de certa maneira, desatualizadas em alguns aspectos, busca abordar de que modo o próprio contexto social pode influenciar novas práticas de ensino e estimular o aprimoramento de processos de aprendizagem da linguagem audiovisual . As etapas deste trabalho perpassam pela discussão bibliográfica de obras publicadas sobre produção de vídeo no espaço escolar; pela fundamentação do método fenomenológico; pelo relato das atividades pedagógicas; pela transcrição das entrevistas seguida da análise dos discursos dos alunos. Esta pesquisa pretende discutir as experiências com produção de vídeo do ponto de vista dos sujeitos envolvidos no processo de ensino-aprendizagem e, assim, poder ampliar perspectivas de trabalho com ensino de audiovisual na escola a partir da reflexão crítica sobre a prática pedagógica / Abstract: This work is the result of reflections and analysis arising from the teaching experience of the researcher in teaching video production to first-year high-school students for a period of four years at a private school network in the city of Campinas - SP. The objective was to evaluate aspects of the students' perception about their own learning from the description of the procedures performed in the classroom and their results. The course "Film and video production", studied as a regular discipline within the Arts curriculum in 2009, was set up in order to encourage in students the development of skills and competencies related to the demands of society in which the audiovisual has come to occupy a prominent space in interpersonal relations as a communication tool. The choice for the phenomenological method based on the student experience therefore aims to deal, with some precision, with an inaccurate and dynamic reality which requires increasingly varied and continuously evolving learning processes. The discussion about the importance of deconstructing pedagogical strategies that are old and, to an extent, out of date, seeks to investigate the extent to which social context can influence new teaching practices and encourage the improvement of learning processes of audiovisual language. The stages of this work include the literature discussion of works published on topics such video production; the grounds of the phenomenological method; the report of educational activities; and the transcription and analysis of student interviews. This research discusses the experience with video production from the point of view of those involved in the teaching-learning process and it could broaden the horizons of researchers seeking to work with audiovisual teaching in schools / Doutorado / Multimeios / Doutora em Multimeios

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The rapid momentum of the technology progress in the recent years has led to a tremendous rise in the use of biometric authentication systems. The objective of this research is to investigate the problem of identifying a speaker from its voice regardless of the content (i.e. text-independent), and to design efficient methods of combining face and voice in producing a robust authentication system. A novel approach towards speaker identification is developed using wavelet analysis, and multiple neural networks including Probabilistic Neural Network (PNN), General Regressive Neural Network (GRNN)and Radial Basis Function-Neural Network (RBF NN) with the AND voting scheme. This approach is tested on GRID and VidTIMIT cor-pora and comprehensive test results have been validated with state- of-the-art approaches. The system was found to be competitive and it improved the recognition rate by 15% as compared to the classical Mel-frequency Cepstral Coe±cients (MFCC), and reduced the recognition time by 40% compared to Back Propagation Neural Network (BPNN), Gaussian Mixture Models (GMM) and Principal Component Analysis (PCA). Another novel approach using vowel formant analysis is implemented using Linear Discriminant Analysis (LDA). Vowel formant based speaker identification is best suitable for real-time implementation and requires only a few bytes of information to be stored for each speaker, making it both storage and time efficient. Tested on GRID and Vid-TIMIT, the proposed scheme was found to be 85.05% accurate when Linear Predictive Coding (LPC) is used to extract the vowel formants, which is much higher than the accuracy of BPNN and GMM. Since the proposed scheme does not require any training time other than creating a small database of vowel formants, it is faster as well. Furthermore, an increasing number of speakers makes it di±cult for BPNN and GMM to sustain their accuracy, but the proposed score-based methodology stays almost linear. Finally, a novel audio-visual fusion based identification system is implemented using GMM and MFCC for speaker identi¯cation and PCA for face recognition. The results of speaker identification and face recognition are fused at different levels, namely the feature, score and decision levels. Both the score-level and decision-level (with OR voting) fusions were shown to outperform the feature-level fusion in terms of accuracy and error resilience. The result is in line with the distinct nature of the two modalities which lose themselves when combined at the feature-level. The GRID and VidTIMIT test results validate that the proposed scheme is one of the best candidates for the fusion of face and voice due to its low computational time and high recognition accuracy.

This study focused on the differences in the knowledge gained between instructionally designed mediated lecture instruction and traditional lecture instruction. The sample used in this study consisted of 107 new hospital employees required to attend an orientation. The experimental group consisted of 43 subjects and the control group consisted of 64 subjects. Each group was given a pre-, post- and post-delayed knowledge test and an attitude test. The following hypotheses were tested: (H₀1) There will be no differences in post-test scores between groups. (H₂) There will be no differences in post-delayed test scores between groups. (H₃) There will be no differences in attitudes between groups. An analysis of covariance was computed on the data to test hypothesis one and hypothesis two and a one-way analysis of variance to test hypothesis three. The results indicated no significant differences on post-test scores and Hypothesis One was retained. Hypothesis Two was rejected as a significant difference indicated an increase in knowledge retained over time by the experimental group. Hypothesis Three was rejected with the experimental group reacting much more favorably to the mediated lecture. The conclusions reached as a result of this study were that both groups were learning, regardless of the method of instruction. Also knowledge was retained over time much better by the experimental group when the information was presented in the instructionally designed mediated format. Finally, the favorable response by the experimental group to the mediated lecture indicated a preference for this teaching format. Recommendations for additional investigations were discussed.

This thesis investigates whether certain practices improve the use of video-mediated communication; specifically video-mediated gazing (the act of looking directly into the camera) and face-to-face familiarisation prior to video-mediated meetings. This is done through comparisons of conditions where such practices are employed and control conditions. The successful adoption of these practices is assessed using a multi-level approach: investigating the communicative process, participant perceptions and task outcome. Participant perceptions are directed towards assessing the media, assessing other participants using the media, perceptions of task performance and communicative success, and perceptions of social co-presence. In cases where task outcome is assessed, an objective measurement of performance is taken. Communicative process is assessed through investigating participants use of gazing behaviour and verbal aspects of process: for example turn length, dialogue length and the numper of interruptions. Verbal aspects of process are also measured using Conversational Games analysis, where the functions of participants' utterances are assessed. The results show that participants who gaze at the camera are perceived more favourably. Accompanying speech with video-mediated gazing also results in improved recall of information. Face-to-face familiarisation alters participant perceptions of others using the media and feelings of social co-presence. It is concluded that for certain applications (specifically social tasks) and with an appropriate level of training (specifically with the use of video-mediated gazing) the use of such strategies benefits video-mediated communication.

The purpose of this study was to make an investigation of the use of audio-visual aids in the conduct of interscholastic athletics for boys in AA High Schools in Texas.