Typescript (photocopy). / Digitized by Kansas Correctional Industries

Résumé : Afin de répondre aux besoins de communication et de divertissement, il ne fait aucun doute que la parole et l’audio doivent être encodés sous forme numérique. En qualité CD, cela nécessite un débit numérique de 1411.2 kb/s pour un signal stéréo-phonique. Une telle quantité de données devient rapidement prohibitive pour le stockage de longues durées d’audio ou pour la transmission sur certains réseaux, particulièrement en temps réel (d’où l’adhésion universelle au format MP3). De plus, ces dernières années, la quantité de productions musicales et cinématographiques disponibles en cinq canaux et plus ne cesse d’augmenter. Afin de maintenir le débit numérique à un niveau acceptable pour une application donnée, il est donc naturel pour un codeur audio à bas débit d’exploiter la redondance entre les canaux et la psychoacoustique binaurale. Le codage perceptuel et plus particulièrement le codage paramétrique permet d’atteindre des débits manifestement inférieurs en exploitant les limites de l’audition humaine (étudiées en psychoacoustique). Cette recherche se concentre donc sur le codage paramétrique à bas débit de plus d’un canal audio. // Abstract : In order to fulfill our communications and entertainment needs, there is no doubt that speech and audio must be encoded in digital format. In"CD" quality, this requires a bit-rate of 1411.2 kb/s for a stereo signal. Such a large amount of data quickly becomes prohibitive for long-term storage of audio or for transmitting on some networks, especially in real-time (leading to a universal adhesion to the MP3 format). Moreover, throughout the course of these last years, the number of musical and cinematographic productions available in five channels or more continually increased.In order to maintain an acceptable bit-rate for any given application, it is obvious that a low bit-rate audio coder must exploit the redundancies between audio channels and binaural psychoacoustics. Perceptual audio coding, and more specifically parametric audio coding, offers the possibility of achieving much lower bit-rates by taking into account the limits of human hearing (psychoacoustics). Therefore, this research concentrates on parametric audio coding of more than one audio channel.

By identifying lip movements and characterizing their associations with speech sounds, the performance of speech recognition systems can be improved, particularly when operating in noisy environments. Various method have been studied by research group around the world to incorporate lip movements into speech recognition in recent years, however exactly how best to incorporate the additional visual information is still not known. This study aims to extend the knowledge of relationships between visual and speech information specifically using lip geometry information due to its robustness to head rotation and the fewer number of features required to represent movement. A new method has been developed to extract lip geometry information, to perform classification and to integrate visual and speech modalities. This thesis makes several contributions. First, this work presents a new method to extract lip geometry features using the combination of a skin colour filter, a border following algorithm and a convex hull approach. The proposed method was found to improve lip shape extraction performance compared to existing approaches. Lip geometry features including height, width, ratio, area, perimeter and various combinations of these features were evaluated to determine which performs best when representing speech in the visual domain. Second, a novel template matching technique able to adapt dynamic differences in the way words are uttered by speakers has been developed, which determines the best fit of an unseen feature signal to those stored in a database template. Third, following on evaluation of integration strategies, a novel method has been developed based on alternative decision fusion strategy, in which the outcome from the visual and speech modality is chosen by measuring the quality of audio based on kurtosis and skewness analysis and driven by white noise confusion. Finally, the performance of the new methods introduced in this work are evaluated using the CUAVE and LUNA-V data corpora under a range of different signal to noise ratio conditions using the NOISEX-92 dataset.

La séparation de sources aveugle dans le cas sous-déterminé est un problème mal posé pour lequel on suppose que les sources sont indépendantes et parcimonieuses dans le domaine temps-fréquence. La séparation se fait alors en deux étapes : une étape d'estimation des paramètres du mélange, suivi d'une étape d'estimation des sources. Les hypothèses faites sur les sources ne sont cependant pas valides sur l'ensemble des points temps-fréquence, si bien que les approches qui traitent naïvement de l'ensemble des points de manière identiques et indépendantes, sont peu robustes pour estimer les paramètres du mélange et les sources. L'objet de cette thèse est d'exploiter la distribution locale du mélange dans les voisinages de chaque point temps-fréquence, afin de : - Détecter les régions temps-fréquence où une seule source est active et d'estimer la direction de la source dominante dans ces régions ; - Estimer la distribution des sources en chaque point temps-fréquence à l'aide de la connaissance sur les paramètres du mélange. L'approche locale que nous proposons est étayée par un algorithme de clustering appelé DEMIX, qui estime de façon robuste les paramètres du mélange dans les cas instantanés et anéchoïques. D'autre part, l'estimation locale de la distribution des sources peut être utilisée pour apprendre des MMG spectraux qui jusqu'à présent nécessitaient une étape d'apprentissage à partir d'exemples. Nous montrons que cette approche améliore l'estimation des sources de plusieurs dB en SDR.

No description available.

The majority of learners perform badly at the end of the formal schooling in South Africa. This point is verified by the poor results after almost every Grade 12 Final examination. The statistics of candidates who wrote the Senior Certificate examination at the end of 1996 reflect a 53,9% pass rate and that of 1997, 47,4% (Department of Education, 1999:12). It was also mentioned that the depicted scenario prompted a national outcry from several sectors of the South African community. This study shows that the grade 12 examination results did not reflect a significant change during the years that followed 1997. The study further pinpoints Science as a learning area that learners fail alarmingly. It also goes on to isolate electricity as an area that is difficult for both the learners and the educators to understand, thereby contributing enormously towards the very high failure rate mentioned earlier. The researcher also found that literature revealed that not much in-service education and training has been done to redress the malpractices that may be the contributory factors towards the high failure rate in question. The researcher introduced the audio-tutorial self-study programme to assess its influence on the knowledge and insight of Science educators. Conclusions are made and the recommendations are drawn based on the findings of the study. / Thesis (M.Ed.)--Potchefstroom University for Christian Higher Education, 2002

Audio description is considered a relatively new research field, and in South Africa it is not yet being used extensively to make visual channels accessible to blind audiences. Therefore research in this field is necessary. The literature review of this study shows that very little empirical research has been done where real audiences were tested. This study set out to test the impact of audio described film on the transportation, identification and comprehension of real audiences. The focus was on mise-en-shot elements specifically and the impact they have on the transportation, identification and comprehension of audiences. A thorough analysis of the two scenes and their audio descriptions showed that in the audio description the emphasis tends to be on the visual elements and not on the way these elements are presented (which forms part of mise-en-shot elements). The way the film is showed to the audience contributes to the film‟s meaning and the director often shows the film to the audience in a specific way to reach a certain effect or feeling in the film. If these mise-en-shot elements are not presented in the audio description of the film it, the blind audience cannot be expected to experience an equivalent effect to that of the sighted audience. In order to test the impact of mise-en-shot elements a methodology based on Bortolussi and Dixon‟s (2010) Psyconarratology was used. Immersion and transportation studies (Green and Brock, 2000 and Tal-Or & Cohen, 2010) were used to develop an experiment for the study. Two groups of respondents were tested by exposing one group to all the available channels of the film and another to only the audio description and soundtrack. The initial hypothesis of this study was that the audience exposed to the audio description and soundtrack of the film would experience less transportation, identification and comprehension due to the loss of mise-en-shot elements in the film. By using T-tests and qualitative comparisons of the responses it was found that the lack of mise-en-shot elements in the film had no statistically significant impact on the transportation of the audience. Furthermore it was found that the lack of mise-en-shot elements has an impact on the identification of the audience. The group that had access to all the channels were more able to identify with the characters. In terms of comprehension it was discovered that there were bigger differences between the two groups in the scenes were the director relied on the visual elements of the film. Thus there are opportunities for further research pertaining to the identification of the audience. Furthermore it is recommended that further research be done to include other film genres as well as alternative ways of doing audio description. South Africa as well as other countries can gain tremendously from the use of audio description to make visual channels accessible to blind audiences. To reach such a goal further research is needed in the field, not only to master the art of audio describing but to also create awareness for this aid. / Thesis (MA (Language Practice))--North-West University, Vaal Triangle Campus, 2013

Virtual Reality (VR) can potentially transport the user to another world. Outside of VR, musical soundtrack is usually placed outside of the scene, referred to as non-diegetic sound. In VR, this could potentially break immersion. Other ways to implement music have to be tested. A test was created consisting of three scenes with a wide selection of “listening modes”, or musical configurations. The listening modes ranged from non-diegetic stereo music via headphones to diegetic, played from speakers inside the VR spaces. 10 respondents played through the scenes in VR, experiencing every listening mode. Respondents then replied to a questionnaire gathering their thoughts on their experience. Results showed that immersion improved the more the experience corresponded to expectations from outside of VR. Non-diegetic listening modes were considered less immersive than diegetic listening modes. This study lays a basic foundation for further research on music in VR with initial guidelines for proper implementation.

The aim of the Musical Training Revolution is to take advantage of the modern educational technology tools, to apply them to the auditory training in a professional music training program. In this paper, the experience of transforming the classroom course in Leveling in Reading and Ear Training is presented, from a university undergraduate Music, to a b-learning mode. b-learning mode of this course is set on a virtual classroom on the Moodle platform. Online work within this virtual classroom included communication forums, academic forums, ear training self-instructive resources and academic tasks. The working strategy of on-line courses considered several aspects: 1) Structure of the virtual classroom. 2) Communication within the virtual classroom. 3) Managing the virtual classroom. 4) Create and organize content. 5) Provide an online study methodology. 6) Design and implementation of online activities. 7) Rate of online activities. 8) Evaluation of the whole process. The results of this experience forced us to rethink the contents of the same course at the following levels due to the substantial progress made. / El objetivo de la Revolución del Entrenamiento Musical es aprovechar las modernas herramientas tecnológicas para la educación, aplicándolas al entrenamiento auditivo, dentro de un programa de formación musical profesional. En este trabajo, se presentará la experiencia de transformación del curso presencial de Nivelación en Lectura y Entrenamiento Auditivo, de un pregrado universitario de Música, a la modalidad b-learning. La modalidad b-learning de este curso se estableció sobre un Aula Virtual en una plataforma Moodle. El trabajo en línea, dentro de esta Aula Virtual, incluyó foros de comunicación, foros académicos, recursos autoinstructivos de entrenamiento auditivo y tareas académicas. La estrategia del trabajo online del curso consideró varios aspectos: 1) Estructura del Aula Virtual; 2) Comunicación dentro del Aula Virtual; 3) Administración del Aula Virtual; 4) Creación y organización de contenidos; 5) Planteamiento de una metodología de estudio en línea; 6) Diseño y puesta en marcha de las actividades en línea; 7) Calificación de las actividades realizadas en línea; 8) Evaluación de todo el proceso. Los resultados obligaron a replantear los contenidos del mismo curso en los niveles siguientes debido a los importantes avances alcanzados.

Obstructive sleep apnoea (OSA) is a common disorder involving repeated cessations of breathing due to airway collapse, causing disruption of sleep cycles. The condition is under-diagnosed and the side effects are many and varied. Currently, the ‘gold standard’ diagnostic tool for OSA is a polysomnogram (PSG) which is carried out overnight in a hospital using multiple sensors. A PSG is expensive to set-up, run and analyse, and some subjects experience different sleep patterns due to the artificial conditions of the sleep laboratory. The aim of this thesis was to find a parsimonious and easy-to-collect set of signals (from the superset of signals recorded in sleep clinics) and other related information (such as demographics), and a set of automated methods that reliably determine which subjects are suitable for standard treatments, i.e. classify subjects requiring treatment (moderate OSA, severe OSA) from those not requiring treatment (normal, snorer, mild OSA), using a smartphone. Data were collected from 1354 subjects in the home using the Grey Flash polysomnographic recording device (Stowood Scientific Instruments, Oxford, UK). Analysis of the audio signal was initially performed using standard speech processing methods, where individual events were annotated and classified. The results achieved (accuracy (Ac) = 69.6%) using this approach were lower than those required for clinical acceptance. In all subsequent work in the thesis, subjects were classified from entire recordings rather than events. Multiscale entropy (MSE) was used to identify non-linear correlations in the audio data and quantify the irregularity of the data over many time scales. The inter-snore interval (ISI) was developed, motivated by clinical intuition. MSE and ISI were then applied to both actigraphy and photoplethysomgraphy (PPG) data, and different combinations of features were analysed. The features which displayed the highest predictive accuracy were derived from the PPG signal (Ac = 89.2%). This work demonstrated that, although audio- and actigraphy-based OSA screening is possible, to achieve clinically acceptable performance PPG remains an important key factor in diagnosis.