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Inter-vehicle Collision Avoidance Strategies For Input-constrained Differential-drive Robots Moving In Shared Environments
No full textThis thesis presents two different collision avoidance and control strategies for coordinated and uncoordinated multi-agent robotic systems. In the considered setup, each agent is a differential-drive robot subject to input constraints on the wheels angular velocities. For the coordinated control problem, we propose a collision-free platooning solution utilizing a leader-follower approach. The leader robot follows a predefined reference trajectory, while the follower robots track the leader's pose with an inter-agent delay that is properly designed to avoid inter-vehicle collision. In particular, by resorting to feedback linearization tools, the kinematic models of both leader and followers are linearized, allowing a formal characterization of the platoon's error dynamics and input constraints. To address the platooning trajectory tracking control problem, we employ a set-theoretic model predictive control strategy which is complemented by an ad-hoc collision avoidance policy ensuring collision-free movement among agents. On the other hand, to address uncoordinated situations where the vehicles move in a shared environment, we propose a novel collision prevention mechanism which is inspired by traditional traffic light mechanisms. The developed framework leverages a set-theoretic model predictive waypoint tracking strategy with feedback linearization, enabling each robot to follow a sequence of waypoints. Moreover, a centralized traffic manager identifies potential collisions using reachability arguments and models potential collisions through a connectivity graph. The collision resolution policy aims to minimize the number of agents required to stop at any given time. Furthermore, taking advantage of a possible finite preview of future waypoints, the traffic manager can also instruct (adjust) the maximum velocity allowed for each vehicle in order to reduce the likelihood of future collisions. Finally, all the strategies presented in this thesis have been validated via hardware-in-loop experiments using three Khepera-IV differential drive robots
Exploring High-Variability Phonetic Training through Text-To-Speech Technology in ESL Pronunciation Pedagogy
Get PDFTraditional language classrooms often face constraints that limit ESL learners’ exposure to varied speech sounds, hindering their pronunciation development. High-Variability Phonetic Training (HVPT) offers a potential solution by exposing learners in diverse speech sounds and accents to improve pronunciation skills. However, the practical implementation of HVPT in everyday language classrooms is still underexplored. This study examines the integration of Text-To-Speech (TTS) technology with HVPT to enhance pronunciation skills among English as a Second Language (ESL) learners beyond traditional classroom settings.
Using a mixed-method design with pretest-posttest evaluations, this study assessed morphophonemic features (past -ed allomorphs) and holistic aspects of pronunciation (i.e., comprehensibility, accentedness). Thirty adult university-level ESL learners from Kuwait were assigned to either a Treatment group (TTS with varied voices) or a Control group (TTS with a single voice). Participants engaged in self-paced sessions over a period of four weeks.
The results revealed significant improvements in phonological awareness of past -ed allomorphy for both groups, with no notable differences observed between them. In terms of the holistic measures of pronunciation development, evaluated by a panel of eleven raters, the Treatment group achieved statistically significant improvements in both comprehensibility and accentedness when compared to the Control group. These findings indicate that while TTS technology enhances phonological awareness irrespective of HVPT implementation, TTS-based HVPT further enhances pronunciation development considering the two holistic measures adopted.
This study highlights the potential of TTS technology to provide variable aural input and improve ESL pronunciation training, offering valuable insights for developing effective and accessible language learning resources
Queer Becomings: Deleuze and Guattari’s Critique of Static Identity Categories
Get PDFIn this paper I argue that trans exclusionary action from cis lesbian, gay, and bisexual (LGB) political pundits is generated and sustained by a need for recognition by the capturing apparatus of the state, thereby conserving heterosexual familial structures and enforcing a need to identify deviant behavior. Anti-trans activists—including those who are often seen as part of the queer community—increasingly find efforts to affirm trans individuals to be a threat to static notions of gender and identity, which, as these anti-trans advocates claim, undermine attempts for integration of cis LGB individuals into the capitalist order. What I take to be at stake in the struggle for trans liberation is less a political issue than a metaphysical one, e.g., how making sexual identities visible to the state cuts off various possibilities of becoming. This paper is not meant to prescribe solutions to the problem of the lack of allyship from cis gay men and cis lesbians, but rather direct to a problem that stems from static identity categories.
The issue brought to light in this paper goes much deeper than merely debating the biology of the trans individual as current political discourse tends to follow. I am arguing that we must take a metaphysical approach to this problem—going past static notions of gender and sexuality as extant and to place in question the need for recognition politics. For Gilles Deleuze and Félix Guattari, it is possible to escape the traps of the political and biological (which in turn generate the terms by which trans people must justify themselves) by shaking up the notion of the static categories of sexual identities and aligning it with minoritarian transness. For the purposes of my thesis, I explore Deleuze and Guattari’s thoughts, in conversation with other philosophers in the wake of May 68, to bolster a key point in the liberation of queer individuals in France. The thesis leans thus heavily on Deleuze and Guattari’s notion of becoming-imperceptible, moving away from a medicalized understanding of transness–which stems from a pathologizing of transness, and in this way conditions my argument regarding the movement of trans and gay identities. Through putting Deleuze and Guattari’s work in relation to these other thinkers, I show that first, the codification of sexual desire as homosexual or non-homosexual, or desire to express a certain gender as trans or cis, has created the conditions more precisely for policing these desires; second, and going further, the more authentic desire and its ability to produce and create has been taken from our hands through the crystallization of these categories
How might photovoice be used in a digital era? Collaborating with rural youth to explore environmental pedagogy
Get PDFThis thesis examines how photovoice as a methodology can be used in a digital era to connect rural youth with their environment. To give agency to rural youth and empower the participants in our environmental crisis, I developed a photovoice workshop to foster a caring relationship with nature by anchoring my approach in environment pedagogy, place-based learning and Paulo Freire's theory of critical-action, critical-consciousness, and active learning. Using an adaptation of Caroline Wang and Mary Ann Burris' photovoice methodology, I adopted Aboulkacem et al.'s (2021) photovoice 2.0 method to address digital photography and the necessity for visual literacy. I facilitated a photovoice workshop for Grades 5 to 8 at a small community two hours north-west of Montreal, Quebec. The workshop was a 6-week extra-curricular activity held in the school library twice a week during the participant's 55-minute lunch break. The workshop's theme was the environment as we explored the forest behind the participant's school to engage in an eco-responsible relationship through photography and group discussions. The outcome was a group exhibit installed in the participant's school, where they invited the local and school community to attend their vernissage.
Keywords: photovoice, environment, photography, visual literac
Experimental and Analytical Investigation of Bond between GFRP Bars and Concrete
No full textThe utilization of fibre-reinforced polymer (FRP) bars in concrete structures has seen a consistent increase in recent years. This growth is attributed to the properties of FRP bars, including corrosion resistance, low density, fatigue resistance, and high tensile capacity. Among various FRP bars, glass FRP (GFRP) bars have attracted notable interest because of their advantageous characteristics, such as exceptional chemical resistance, cost-effectiveness, and versatile applicability. The bond strength between GFRP bars and concrete is crucial for the serviceability and ultimate performance of GFRP-reinforced concrete (RC) structures. GFRP bars exhibit anisotropy, linear elasticity, and a lower modulus of elasticity compared to steel bars, rendering the design guidelines for steel inapplicable to GFRP. Therefore, a thorough investigation into the bond is essential to ensure effective force transfer between GFRP bars and concrete.
In this thesis, the bond strength and bond-slip behaviour of high-modulus GFRP bars were investigated using pullout and beam splice tests. In Phase 1 of the experimental study, 48 pullout specimens were constructed and tested to investigate the local bond-slip behaviour between single and bundled ribbed GFRP bar in concrete. The study considered the effects of bar embedded length, specimen dimensions, GFRP surface profiles, the presence of steel transverse reinforcement, and bundling of the bars on the pullout strength. The experimental data were used to calibrate existing analytical bond-slip models for ribbed GFRP bars. The calibrated values could be utilized in numerical modelling for concrete elements internally reinforced with ribbed GFRP bar. In second Phase, lap splice tests have been conducted on 20 full-scale beams with a focus on investigating the effects of GFRP bar’s surface profile and GFRP transverse reinforcement on the bond strength. The study evaluated the influence of different surface profiles, including ribbed, sand-coated, and grooved, as well as GFRP stirrup spacing, bar splice length, and bar diameter, on splice strength. A comprehensive dataset was collected from both the literature and the present study to evaluate the reliability of existing bond models. A new model was proposed to enhance bond prediction accuracy. Additionally, the bond contributions of steel and GFRP transverse reinforcement were assessed and compared.
Furthermore, the lower modulus of elasticity in GFRP compared to steel bars leads to increased crack width and deflections in GFRP-RC structures. Consequently, the design of GFRP-RC structures is usually governed by the serviceability limit state. Effective control of crack width during the service stage of GFRP-RC structures is of paramount importance. To address this, the present research also investigated the capability of machine learning (ML) models to predict crack width in GFRP-RC structures, with the aim of enhancing prediction accuracy compared to existing code and literature models. Various ML models, including extreme gradient boosting (XGBoost), random forest (RF), K-nearest neighbours (KNN), light gradient boosting machine (LightGBM), gradient boosting (GB), adaptive boosting (AdaBoost), Ridge, and Lasso, were utilized to improve the prediction accuracy of crack width in GFRP-RC beams
The Role of Music Therapy in Developing Healthy Coping Skills for Adolescents Experiencing Eating Disorders: A Philosophical Inquiry
Get PDFAs music therapy services continue to become more accessible, music therapists are working with a wider range of clientele with specific needs. Adolescents experiencing eating disorders (AEED) are among those with whom music therapists work to provide support throughout the treatment process. The purpose of this philosophical inquiry was to synthesize existing knowledge and evidence to substantiate the argument that music therapy (as realized within three categories of experience) is an ideal way to support the development of healthy coping skills for adolescents experiencing eating disorders. The methodology involved clarifying the research terms, exposing and evaluating underlying assumptions, relating ideas as systematic theory, and using argument as a primary mode of inquiry. The findings discussed how adolescents engage with music, current approaches in music therapy for the targeted clientele, and considerations for music therapists working with AEED. The findings confirm that music therapy can be a valuable resource for AEED, providing a space to reflect on coping patterns through composition, improvisation, and receptive music therapy experiences
From Cans to Kins: Eating as Becoming-With and Relational Cannibalism in Larissa Lai’s The Tiger Flu
Get PDF“What’s the worst thing you’ve ever done for food?” Cordova girl Myra asks protagonist Kora in Larissa Lai’s novel The Tiger Flu. Myra’s question does not simply demand an answer at the individual level within a fictional narrative, but needs to be extended to actual food systems. What is it that we do in order to consume beings as food? The novel’s fictional food systems reflect the nonfictional ones where the forms of life humans eat and call food are often understood as product rather than beings with whom we are in relation. Such treatment is based on the assumption that the human body is a system with fixed boundaries separating it from other species, and that reason makes humans an exceptional species. Against these beliefs, I argue that those made into food can be understood as kin rather than product. I read this relational ontological mode throughout Lai’s novel where food circulation, ingestion, and zoonosis indicate a range of ways bodies infiltrate one another despite rigid policing. I examine practices of food preservation and social control in The Tiger Flu as forms of containment that separate human subjects from commodified, racialized, and dehumanized others. Containment is challenged by characters’ becoming-with those they eat and those with whom they share meals. When the first category bleeds into the second, consumption becomes cannibalism. I show that the novel not only denounces capitalist relations for which cannibalistic eating is a model but also proposes the alternative paradigm of relational cannibalism where eating is an act of trans-corporeal integration maintaining kinship beyond death
In-plane Cyclic Response of Flexural-Dominated Partially Grouted Reinforced Masonry Shear Walls with Boundary Elements
Get PDFReinforced masonry shear walls (RMSWs) are commonly used in seismic regions, but predicting their behaviour is challenging due to the composite nature of materials like masonry blocks, mortar, steel rebars, and grout. This complexity is heightened in partially grouted (PG) walls, where stiffness discontinuities occur at interfaces between grouted and ungrouted cells. The scarcity of experimental data on the materials’ properties has further complicated the development of accurate analytical models.
This research aims to enhance the lateral performance of PG masonry shear walls and develop a reliable analytical model. The study is divided into two main Phases: analytical and experimental. In the analytical phase (Phase I), a nonlinear finite element model was developed and validated against experimental data from the literature. Due to the lack of material properties in existing studies, assumptions were made to fill these gaps. The model generated a comprehensive matrix of 196 numerical models, covering a wide range of parameters such as aspect ratio, spacing between grouted cells, axial load, reinforcement ratios, and grouted and ungrouted compressive strengths. In the experimental phase (Phase II), 84 masonry prisms were tested to evaluate the compressive, shear, and tensile properties of grouted, ungrouted, and boundary element masonry assemblages. Consequently, using these components, two half-scale PG shear wall specimens with C-shaped boundary elements were constructed and tested under high axial loads and in-plane cyclic loading. These tests represented the lower storey of RMSWs in of a six- and twelve-storey buildings and examined the impact of full versus partial grouting and aspect ratios.
The analytical investigation resulted in three penta-linear load-displacement backbone models for flexural-dominated, shear-dominated, and combined failure modes, along with secant stiffness expressions for each wall type. These models were validated against additional data, showing good accuracy for PG walls. The study also identified the inadequacy of the stiffness reduction factor in CSA S304-14 for PG walls, leading to the derivation of new coefficients. The experimental results provided detailed stress-strain data for various mechanical properties, and wall tests showed ductile performance with high energy dissipation, exceeding North American design standards before strength degradation began
Shaping Grief: A Lesbian Poetics of Dismembering
Get PDFA lesbian poetics of dismembering, as I argue, is a creative process that disorients from general notions of body and memory. Through examining such a poetics, found across a selection of lesbian works of grief, I critique the modes by which the state coerces, co-opts, and mobilizes a certain crafting of the body and memory in efforts to amass and concentrate power, as well as how desire and grief are taken up both in service of, and counter to, such statecraft operations. I aim to both emphasize and take part in a lesbian poetics that destroys the very terms of empire–fleeing its own uptake and offering nothing to fill this gap; no balm for this uncertainty
The Effects of Quiet Quitting in a Stochastic Dynamic Model
Get PDFA fundamental tradeoff in economics is allocating time between work and leisure. The COVID-19 pandemic disrupted conventional work patterns, prompting individuals to reconsider how they had previously allocated their time. A modest but growing body of literature has identified a structural shift in the labour market, termed “quiet quitting.” The term quiet quitting refers to disengaging from one’s job and completing only the minimum required work, driven by a desire for greater work-life balance. Since 2020, this phenomenon has emerged as a key topic in research, with studies focusing on its impact and the urgent need for employers to address it. This structural shift has been particularly evident along the intensive margin, as individuals engaged with quiet quitting do not exit the labour force. Despite the growing body of literature, there is a lack of research quantifying quiet quitting and measuring its impact on the economy, particularly using dynamic stochastic models. This paper explores the impact of quiet quitting on the economy using the Hansen (1985) real business cycle model with indivisible labour. I identify two key parameters of the model that influence both aggregate and individual-level hours and conduct a series of experiments by introducing exogenous shifts into these parameters. The model effectively captures key features of quiet quitting and its impact on key economic variables, including output, consumption, capital and investment. The results show that when quantifying quiet quitting by the drop in hours between 2019 and 2022, output, consumption, investment and the capital stock decrease by 3.0-4.3 percent. The findings also demonstrate that with quiet quitting, output, investment, hours and the capital stock become less volatile