The purpose of this study was to investigate the relationship of the Utah State University concurrent enrollment program to the achievement (GPA), recruitment, and retention of program participants after joining Utah State University. Three administrative approaches to the management of concurrent enrollment programs were identified for the purpose of this study: Level One, Level Two, and Level Three. Level One involved high school teachers who taught and graded the concurrent enrollment program courses. In Level Two, high school teachers taught the courses, but University professors prepared exams and graded the papers. In Level Three, teaching, exam preparation, and paper grading were all executed by university faculty. To determine the effects of the three different administrative approaches on concurrent enrollment programs, four research questions were formulated: (1) For the three different administrative approaches to the management of the concurrent enrollment program practiced by Utah State University, are there different GPAs for comparable selected major courses for program participants? (2) For the three different administrative approaches, are there differences in the proportion of high school students recruited to Utah State University? (3) For the three different administrative approaches, are there different rates of retention for participating students one year after joining Utah State University? (4) For the three different administrative approaches, are there greater GP As and retention rates when compared with Utah State University's regular freshmen population? A sample from the target population of concurrent enrollment program participants from 1988 to 1991 was used. The data were collected from existing Utah State University records. The dependent variables were GPA, recruitment, and retention, while administrative approaches were the three levels of the independent variable. The means for the Level One approach were statistically and educationally significant as compared to the remaining two levels. One year after joining Utah State University, the recruited concurrent enrollment program participants tended to remain with Utah State University. Therefore, it was recommended that the program be supported with the emphasis on encouraging more high school teachers to teach concurrent enrollment courses in the future.

The purpose of this study was to test the feasibility of allowing concurrent enrollment in the College of Agriculture to selected high schools in the state of Utah. "Introduction to Agricultural Plant Science" (Plant Science 100 ) was the course being tested. A purposive sampling technique was used to identify four vocational agriculture programs to participate. There were 86 high school students in the study and 38 college students who took the course on campus at Utah State University. In this study, 47.7% of the high school students passed the course with a 70% average or above. Comparisons between high school and college student performance showed a marked difference in percentage points accumulated on exams and the final, with the college students performing more consistently.

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Objective: Opioid use disorder (OUD) remains a major public health problem within Canada and worldwide. Increasing our understanding of psychiatric comorbidity in this population is the focus of this thesis. Methods: We used observational cohort data from two prospective studies of individuals with OUD receiving opioid agonist treatment (OAT). These data allowed us to examine risk factors for psychological symptoms and psychiatric comorbidities, to examine differences between youth and adults, and to assess the sensitivity and specificity of self-reported diagnoses against those made using a validated tool. We linked cohort data to Provincial health administrative data holdings to explore mental healthcare service use and associated costs. Discoveries: This work provides new information on psychiatric comorbidity among individuals receiving treatment for OUD and carries implications that can inform future research to shape clinical care. The main conclusions drawn from this work were: 1) routine assessment of psychological symptoms, including suicidal ideation, in this population is warranted; 2) self- report of psychiatric disorders is not sufficiently sensitive to identify psychiatric comorbidity and other methods such as validated tools should be considered; 3) trauma and post-traumatic stress disorder are common in individuals with OUD and their impact may not be captured by solely measuring substance-related outcomes in treatment; 4) youth with OUD differ from adults in their health risk behaviours and psychiatric comorbidities and likely require distinct services and supports; and 5) outpatient non-substance-related mental healthcare for individuals with OUD is provided largely by primary care physicians for whom increased resources and training are needed, and emergency department visits and hospitalizations (which are costlier to the system) are not uncommon. Conclusion: Psychiatric comorbidity is prevalent in OUD and integrated mental health and addictions treatment requires clinical and research attention. Future studies are needed to test interventions and build an evidence base to inform clinical management. / Thesis / Doctor of Philosophy (PhD) / Opioid addiction has led to the deaths of tens of thousands of Canadians and many more people worldwide. Many individuals with opioid addiction also have other mental health problems that can be barriers to recovery from opioid use. Our current healthcare services are disconnected, and most people do not have access to treatments that can help with both addiction and other mental health problems at the same time. We conducted five studies looking at mental health problems within people who have opioid addiction. We focused on understanding risk factors, diagnoses, treatment, and use of mental healthcare services for individuals with opioid addiction and other mental health problems. Our findings provide new information on unmet mental health needs for people with opioid addiction. This information will help treatment programs, doctors, and policy makers better understand who needs more supports and consider how to improve services.

Dual task performance and the interaction of tasks has been the subject of much research. When tasks are performed together they affect each other to varying degrees depending upon such factors as the similarity of the tasks, their difficulty, and whether one task is given preference over another. In this study, task preference was investigated under divided attention conditions in order to determine what effect preference had on task performance. Twenty young adults took part in this study and were randomly assigned into two groups. Each group was experimentally motivated to favor one of the two tasks – either speaking a "tongue-twister" or tracking a moving target on a screen with a computer mouse. Each participant performed the tasks in both an isolated and combined conditions. The measurements of task performance (tracking scores, utterance duration, lower lip and jaw displacement, lower lip and jaw velocity, upper lip-lower lip correlation, spatiotemporal index, and sound pressure level) were then analyzed to determine how task preference affected the participant's performance. It was expected that the preferred task's performance would not suffer when performed in the dual task situation. Although some trends were noted in the predicted direction, no statistically significant results were found as a function of task preference. There were, however, some gender effects. Men were found to have significantly higher intensity than women during the speaking tasks in both the dual and isolated task conditions, and they were also found to perform better than women on the motor tracking task in both the dual and isolated task conditions.

As progress pushes the boundaries of both the performance of new hardware components and the computational capacity of modern computers, the requirements on the performance of robotic systems are becoming more and more demanding. The objective of this thesis is to demonstrate that concurrent design (Co-Design) is the approach to follow to design hardware and control for such high-performance robots. In particular, this work proposes a co-design framework and an algorithm to tackle two main issues: i) how to use Co-Design to benchmark different robotic systems, and ii) how to effectively warm-start the trajectory optimization (TO) problem underlying the co-design problem aiming at global optimality. The first contribution of this thesis is a co-design framework for the energy efficiency analysis of a redundant actuation architecture combining Quasi-Direct Drive (QDD) motors and Series Elastic Actuators (SEAs). The energy consumption of the redundant actuation system is compared to that of Geared Motors (GMs) and SEAs alone. This comparison is made considering two robotic systems performing different tasks. The results show that, using the redundant actuation, one can save up to 99% of energy with respect to SEA for sinusoidal movements. This efficiency is achieved by exploiting the coupled dynamics of the two actuators, resulting in a latching-like control strategy. The analysis also shows that these large energy savings are not straightforwardly extendable to non-sinusoidal movements, but smaller savings (e.g., 7%) are nonetheless possible. The results highlight that the combination of complex hardware morphologies and advanced numerical Co-Design can lead to peak hardware performance that would be unattainable by human intuition alone. Moreover, it is also shown how to leverage Stochastic Programming (SP) to extend a similar co-design framework to design robots that are robust to disturbances by combining TO, morphology and feedback control optimization. The second contribution is a first step towards addressing the non-convexity of complex co-design optimization problems. To this aim, an algorithm for the optimal control of dynamical systems is designed that combines TO and Reinforcement Learning (RL) in a single framework. This algorithm tackles the two main limitations of TO and RL when applied to continuous-space non-linear systems to minimize a non-convex cost function: TO can get stuck in poor local minima when the search is not initialized close to a “good” minimum, whereas the RL training process may be excessively long and strongly dependent on the exploration strategy. Thus, the proposed algorithm learns a “good” control policy via TO-guided RL policy search. Using this policy to compute an initial guess for TO, makes the trajectory optimization process less prone to converge to poor local optima. The method is validated on several reaching problems featuring non-convex obstacle avoidance with different dynamical systems. The results show the great capabilities of the algorithm in escaping local minima, while being more computationally efficient than the state-of-the-art RL algorithms Deep Deterministic Policy Gradient and Proximal Policy Optimization. The current algorithm deals only with the control side of a co-design problem, but future work will extend it to include also hardware optimization. All things considered, this work advanced the state of the art on Co-Design, providing a framework and an algorithm to design both hardware and control for high-performance robots and aiming to the global optimality.

Covert channels are means of communication that allow agents in a system to transfer information in a manner that violates the system’s security policy. Covert channels have been well studied in the constrained and old sense of the term where two agents are communicating through a channel while an intruder interferes to hide the transmission of a message. In an increasingly connected world where modern computer systems consist of broad and heterogeneous communication networks with many interacting agents, distributed covert channels are becoming increasingly available. For these distributed forms of covert channels, there are shortcomings in the science, mathematics, fundamental theory, and tools for risk assessment, and for proposing mechanisms and design solutions for averting these threats. Since current formal methods for specifying concurrent systems do not provide the tools needed to efficiently tackle the problem of distributed covert channels in systems of communicating agents, this thesis proposes Communicating Concurrent Kleene Algebra (C²KA) which is an extension to the algebraic model of concurrent Kleene algebra (CKA) first presented by Hoare et al. C²KA is used to capture and study the behaviour of agents, and description logic is used to capture and study the knowledge of agents. Using this representation of agents in systems of communicating agents, this thesis presents a formulation and verification approach for the necessary conditions for the existence of distributed covert channels in systems of communicating agents. In this way, this thesis establishes a mathematical framework for the modelling, analysis, and mitigation of distributed covert channels in systems of communicating agents. This framework enhances the understanding of covert channels and provides a basis for thinking and reasoning about covert channels in new ways. This can lead to a formal foundation upon which guidelines and mechanisms for designing and implementing systems of communicating agents that are resilient to covert channels can be devised. / Thesis / Doctor of Philosophy (PhD)

With the increased application of large eddy simulations and hybrid Reynolds-averaged Navier-Stokes techniques, the generation of realistic turbulence at inflow boundaries is crucial for the accuracy of numerical results. In this dissertation research, two novel turbulence inflow generation methods are derived and validated. The first method, the Triple Hill's Vortex Synthetic Eddy Method, is a new type of synthetic eddy method, where the fundamental eddy is constructed through a superposition of three orthogonal Hill's vortices. The amplitudes of the three vortices that form the fundamental eddy are calculated from known Reynolds stress profiles through a transformation from the physical reference frame to the principal-axis reference frame. In this way, divergenceree anisotropic turbulent velocity fields are obtained that can reproduce a given Reynolds stress tensor. The model was tested on isotropic turbulence decay, turbulent channel flow, and a spatially developing turbulent mixing layer. The Triple Hill's Vortex Synthetic Eddy Method exhibited a quicker recovery of the desired turbulent flow conditions when compared with other current synthetic turbulence methods. The second method is the Control Forced Concurrent Precursor Method which combines an existing concurrent precursor method and a mean flow forcing method with a new extension of the controlled forcing method. Turbulent inflow boundary conditions are imposed through a region of body forces added as source terms to the momentum equations of the main simulation which transfer flow variables from the precursor simulation. Controlled forcing planes imposed in the precursor simulation, allow for specific Reynolds stress tensors and mean velocities to be imposed. A unique feature of the approach is that the proposed fluctuating flow controlled forcing method can be applied to multiple fluctuating velocity components and couple their calculation to amplify the existing fluctuations present in the precursor flow field so that prescribed anisotropic Reynolds stress tensors can be reproduced. The new method was tested on high and low Reynolds number turbulent boundary layer flows, where the proposed fluctuating flow controlled forcing method greatly accelerated the development of the turbulent boundary layers when compared with cases without controlled forcing and with only the original controlled forcing.

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