Purpose and objective: A good life includes opportunities to practice self-determination, to participate in and contribute to society, to have meaningful relationships, and opportunities for self-development as well as physical, emotional, and financial health and security (Verdugo et al., 2012). People labelled with an intellectual disability (PLWID) have had limited opportunities to experience these good things in life and to share their own perspectives about a good life. The purpose of this study was to learn from PLWID who face significant barriers to communication about what they most value as part of a good life. My research was situated within the sociohistorical context of the province of Ontario. My main research questions were: (1) What is a good life from the perspectives of PLWID who use various forms of augmentative and alternative forms of communication (AAC)? (2) What can we learn from past advocacy efforts? (3) What are the possibilities and limitations of participatory audio/visual methods for enabling PLWID to articulate their vision of a good life? Methods: To explore these research questions, I conducted three separate but related studies. The first study consists of six narratives of intellectual disability advocacy that has taken place in Ontario. A focus group session advised me regarding the choice of narratives to be included in the study. To conduct the second study, I adopted various research methods, including participatory audio/visual methods, inclusive research methods and narrative approaches. I facilitated a series of five workshops for five participants labelled as having an intellectual or developmental disability and facing significant barriers to communication and six supporters living in the Ottawa Region. Combining audio/visual and inclusive methods and drawing from augmentative and alternative communication (AAC), supported decision-making (SDM) and Supported Conversation for Adults with Aphasia (SCA™), participants received assistance to think about a good life. A total of 34 video vignettes communicate participants’ perspectives. Finally, to conduct the third study, I used audio/visual methods to document the participatory process of exploring a good life with participants and their supporters. Results: The results reveal that the desire for assistance to practice autonomy and the desire to contribute to shaping supports and services has been at the heart of intellectual disability advocacy efforts. Further, PLWID value participation and relationships as part of a good life. Participation in arts and sports is especially important as are relationships with family and friends. Results demonstrate that using participatory audio/visual methods combined with strategies drawn from SDM, AAC and SCA™ provide practical assistance to PLWID when thinking about and communicating their visions and ideas of the good. Conclusion and implications: The findings of this research indicate the need to continue exploring methodological approaches that facilitate the participation of PLWID and others who face barriers to communication and cognition in research and beyond. The three studies support a radically individual and relational conceptualization of autonomy and decision-making. As such, they suggest the need to rethink accepted ideas about self-determination, including reasoning and decision-making. Finally, the results support the need for individualized assistance that accommodates each person’s cognitive and communication abilities to enable meaningful participation. They also suggest the need for fundamental systemic changes that begin with practicing equality and forms of radically inclusive democracy in all our relations.

L'environnement urbain est le siège de fortes nuisances sonores notamment générées par les moyens de transport. Afin de lutter contre ces nuisances, la réglementation européenne impose la réalisation de cartographies de bruit. Dans ce contexte, des travaux fondamentaux sont menés autour de la propagation d'ondes acoustiques basses fréquences en milieu urbain. Différents travaux de recherche récents portent sur la mise en œuvre de méthodes ondulatoires pour la propagation d'ondes acoustiques dans de tels milieux. Le coût numérique de ces méthodes limite cependant leur utilisation dans un contexte d'ingénierie. L'objectif de ces travaux de thèse porte sur l'approximation unidirectionnelle de la propagation des ondes, appliquée à l'acoustique urbaine. Cette approximation permet d'apporter des simplifications à l'équation d'onde afin de limiter le temps de calcul lors de sa résolution. La particularité de ce travail de thèse réside dans la prise en compte des variations, continues ou discontinues, de la largeur des rues. Deux formalismes sont utilisés : l'équation parabolique et une approche multimodale. L'approche multimodale sert de support à une étude théorique sur les mécanismes de couplages de modes dans des guides d'ondes irréguliers bidimensionnels. Pour cela, le champ de pression est décomposé en fonction du sens de propagation des ondes à la manière d'une série de Bremmer. La contribution particulière de l'approximation unidirectionnelle est étudiée en fonction des paramètres géométriques du guide d'ondes, ce qui permet de mieux cerner les limites de validité de cette approximation. L'utilisation de l'équation parabolique a pour but une application à l'acoustique urbaine. Une transformation de coordonnées est associée à l'équation parabolique grand angle afin de prendre en compte l'effet de la variation de la section du guide d'ondes. Une méthode de résolution est alors spécifiquement développée et permet une évaluation précise du champ de pression. D'autre part, une méthode de résolution de l'équation parabolique grand angle tridimensionnelle est adaptée à la modélisation de la propagation acoustique en milieu urbain. Cette méthode permet de tenir compte des variations brusques ou continues de la largeur de la rue. Une comparaison avec des mesures sur maquette de rue à échelle réduite permet de mettre en avant les possibilités de la méthode. / The urban environment is the seat of loud noise generated by means of transportation. To fight against these nuisances, European legislation requires the achievement of noise maps. In this context, fundamental work is carried around the propagation of acoustic low-frequency waves in urban areas. Several recent research focuses on the implementation of wave methods for acoustic wave propagation in such environments. The computational cost of these methods, however, limits their use in the context of engineering. The objective of this thesis focuses on the one-way approximation of wave propagation, applied to urban acoustics. This approximation allows to make simplifications on the wave equation in order to limit the computation time. The particularity of this thesis lies in the consideration of variations, continuous or discontinuous, of the width of streets. Two formalisms are used: parabolic equation and a multimodal approach. The multimodal approach provides support for a theoretical study on the mode-coupling mechanisms in two-dimensional irregular waveguides. For this, the pressure field is decomposed according to the direction of wave propagation in the manner of a Bremmer series. The specific contribution of the one-way approximation is studied as a function of the geometric parameters of the waveguide, which helps identify the limits of validity of this approximation. Use of the parabolic equation is intended for application to urban acoustic. A coordinate transformation is associated with the wide-angle parabolic-equation in order to take into account the variation effect of the waveguide section. A resolution method is developed specifically and allows an accurate assessment of the pressure field. On the other hand, a solving method of the three-dimensional parabolic-equation is suitable for the modeling of acoustic propagation in urban areas. This method takes into account sudden or continuous variations of the street width. A comparison with measurements on scaled model of street allows to highlight the possibilities of the method.