VictorJuiz/thesis huggingface dataset:
Enhancing Knowledge Building Discourse in Early Primary Education: Effects of Formative Feedback
Keywords: Knowledge building
formative feedback
early primary
knowledge building environments
knowledge building discourse

This research focuses on a Knowledge Building pedagogical approach and investigates ways to boost students’ competencies in knowledge creation processes, specifically their ability to contribute productively to high-level explanation-seeking discourse. This study uses a design-based methodology to explore how pedagogical and technological innovations can enhance students’ ways of contributing to knowledge building discourse, and examines whether expanding students’ contribution repertoire helps them to advance community knowledge in general. Gains associated with a Knowledge Building approach for secondary and post-secondary students are widely documented. This research adds to this body of literature by showing how a Knowledge Building approach can be productively engaged at the early primary level. This work also contributes to studies exploring automated feedback and assessment tools that can help boost student capacities for building new knowledge. The research was conducted in three main phases. The first phase mapped the ways that students from Grades 1-6 (n = 102) contribute to their naturally occurring Knowledge Building discourse in order to provide baseline data for subsequent design experiments. The following two phases corresponded to two design iterations that involved work in Grade 2 science and that tested different types of formative feedback. Design Cycle 1 (n = 42) focused on testing supports to boost low-frequency contribution types. Design Cycle II (n = 43) aimed to reproduce and improve results from the first iteration. In both design cycles, pedagogical supports included whole-class metadiscourse sessions, while technological supports consisted of contribution and content-oriented feedback tools that offered students a meta-perspective on their own discourse, including Word Clouds (Cycle 1), Concept Clouds (Cycle 1-2), visualizations produced by the Metadiscourse Tool (Cycle 1-2), and verbal scaffolds (Cycle 1-2). Analyses of data revealed that these supports helped students to significantly increase their engagement with targeted contribution types, diversify their general contribution repertoire, and advance collective knowledge beyond that attained by their peers in prior years. This research provides empirical evidence that Knowledge Building inquiry can be effectively engaged at the primary level, and offers usable artifacts tested and shown to be conducive for helping young students raise the level of their Knowledge Building discourse.
Regret-based Reward Elicitation for Markov Decision Processes
Keywords: Decision Making
Robust Optimization
Preference Elicitation
Artificial Intelligence
Planning under Uncertainty
Markov Decision Processes

Markov decision processes (MDPs) have proven to be a useful model for sequential decision- theoretic reasoning under uncertainty, yet they require the specification of a reward function that can require sophisticated human judgement to assess relevant tradeoffs. This dissertation casts the problem of specifying rewards as one of preference elicitation and aims to minimize the degree of precision with which a reward function must be specified while still allowing optimal or near-optimal policies to be produced. We demonstrate how robust policies can be computed for MDPs given only partial reward information using the minimax regret criterion. Minimax regret offers an intuitive bound on loss; however, it is computationally intractable in general. This work develops techniques for exploiting MDP structure to allow for offline precomputation that enables efficient online minimax regret computation. To complement this exact approach we develop several general approximations that offer both upper and lower bounds on minimax regret. We further show how approximations can be improved online during the elicitation procedure to balance accuracy and efficiency. To effectively reduce regret, we investigate a spectrum of elicitation approaches that range from the computationally-demanding optimal selection of complex queries about full MDP policies (which are informative, but, we believe, cognitively difficult) to the heuristic selection of simple queries that focus on a small set of reward parameters. Results are demonstrated on MDPs drawn from the domains of assistive technology and autonomic computing. Finally we demonstrate our framework on a realistic website optimization domain, per- forming elicitation on websites with tens of thousands of webpages. We show that minimax regret can be efficiently computed, and develop informative and cognitively reasonable queries that quickly lower minimax regret, producing policies that offer significant improvement in the design of the underlying websites.
Effective Heuristic-based Test Generation Techniques for Concurrent Software
Keywords: Concurrent Software
Testing

With the increasing dependency on software systems, we require them to be reliable and correct. Software testing is the predominant approach in industry for finding software errors. There has been a great advance in testing sequential programs throughout the past decades. Several techniques have been introduced with the aim of automatically generating input values such that the executions of the program with those inputs provide meaningful coverage guarantees for the program. Today, multi-threaded (concurrent) programs are becoming pervasive in the era of multiprocessor systems. The behaviour of a concurrent program depends not only on the input values but also on the way the executions of threads are interleaved. Testing concurrent programs is notoriously hard because often there are exponentially large number of interleavings of executions of threads that has to be explored. In this thesis, we propose an array of heuristicbased testing techniques for concurrent programs to prioritize a subset of interleavings and test as many of them as possible. To that end, we develop: (A) a sound and scalable technique that based on the events of an observed execution, predicts runs that might contain null-pointer dereferences. This technique explores the interleaving space (based on the observed execution) while keeping the input values fixed and can be adapted to predict other types of bugs. (B) a test generation technique that uses a set of program executions as a program under-approximation to explore both input and interleaving spaces. This technique generates tests that increase branch coverage in concurrent programs based their approximation models. (C) a new heuristic, called bounded-interference, for input/interleaving exploration. It is defined based on the notion of data-flow between threads and is parameterized by the number of interferences among threads. Testing techniques that employ this heuristic are able to provide coverage guarantees for concurrent programs (modulo interference bound). (D) a testing technique which adapts the sequential concolic testing to concurrent programs by incorporating the bounded-interference heuristic into it. The technique provides branch coverage guarantees for concurrent programs. Based on the above techniques, we have developed tools and used them to successfully find bugs in several traditional concurrency benchmarks.
Delayed Versus Immediate Corrective Feedback on Orally Produced Passive Errors in English
Keywords: timing of corrective feedback
corrective feedback
error correction
second language acquisition
learner preferences for corrective feedback
timing of instruction
form-focused instruction
second language learning
second language pedagogy
cognitive aspects of language learning
ESL
English as a second language
second language teaching
English passive voice
L2 learning
L2 teaching
types of corrective feedback
correction
reactivation and reconsolidation
cognitive comparison
skill acquisition
proceduralization
delayed corrective feedback
immediate corrective feedback
second language education
SLA

Research demonstrating the beneficial effects of corrective feedback (CF) for second language (L2) learning (e,g., Li, 2010) has almost invariably resulted from studies in which CF was provided immediately. Yet teachers are often encouraged to delay CF to avoid interrupting learners (Harmer, 2001). This study investigates how differences in the timing of CF on oral production affect L2 learning and learners’ reactions to CF. Theoretically, Immediate CF may facilitate L2 development by allowing learners to immediately compare their errors to accurate models (i.e., recasting, e.g., Doughty, 2001). The effectiveness of Immediate CF has also been linked to skill acquisition theory because some CF (i.e., prompting) is hypothesized to help learners proceduralize their L2 knowledge (Ranta & Lyster, 2007). This thesis introduces additional theoretical explanations to explain the effectiveness of both Immediate and Delayed CF. For example, reactivation and reconsolidation theory (Nader & Einarsson, 2010) holds that long-term mental representations are susceptible to change when they are recalled. Thus, both Immediate and Delayed CF may help learners alter their incorrect mental representations of language features if that CF reminds learners of those incorrect representations and provides them with accurate models. In a laboratory-based study, 90 intermediate-level adult ESL learners were randomly assigned to Immediate, Delayed, and No CF conditions. Learners took three pre-tests to measure their knowledge of the English passive construction: an aural grammaticality judgment test (AGJT), an oral production test (OPT), and a written error correction test (ECT). Next, they received some brief instruction on the passive. Learners then completed three communicative tasks in which the CF conditions were provided. These tasks were followed by immediate and delayed post-tests. Learners’ reactions to CF were elicited with a questionnaire. Mixed-design one-way ANOVAs revealed statistically significant improvement for all conditions over time on all measures, but no statistically significant differences between conditions. The questionnaires revealed that learners prefer Immediate CF, but that Immediate CF may constrain CF noticeability and learners’ independence, while Delayed CF may cause anxiety or embarrassment. In summary, altering the timing of CF did not differentially affect L2 development, but it did elicit different reactions from learners.
Defining Immune Correlates of HIV Susceptibility in the Foreskin
Keywords: HIV
T cells
Circumcision

HIV is a predominantly sexually transmitted infection that has infected over 60 million people and been responsible for 60 million deaths. To date, non-antiretroviral microbicides have failed to prevent HIV acquisition, or even increased it. This is likely because HIV preferentially infects activated immune cells (CD4+ T cells), taking advantage of the body’s attempts to defend itself. Therefore, relative immunoquiescence, as opposed to immune activation, may be protective. I hypothesized that men who are biologically more susceptible to HIV would have increased foreskin CD4 T cell activation, while the opposite would be true of men who are relatively resistant. The foreskin has recently been identified as a major site of HIV acquisition, but little previous research has been performed on this tissue. I therefore developed novel techniques to isolate viable, immunologically functional T cells from foreskin tissue. I then worked with the Rakai Health Sciences Program in Uganda to identify men undergoing elective circumcision who are HIV-Exposed but have remained SeroNegative (HESN, relatively resistant to HIV), and men with Herpes Simple Virus-2 infection (HSV-2+, relatively susceptible to HIV). I collected sub-preputial swabs and foreskin tissue from these men, and characterized numerous immune parameters in their samples. I found that HSV-2+ men had an increased relative abundance of CD4 T cells co-expressing the HIV receptor CCR5. In contrast, I found that HESN men had a decreased relative abundance of activated T cells (CD4/8 T cells producing TNFα) and Th17 cells (a pro-inflammatory T cell subset known to be particularly susceptible to HIV). Additionally, foreskin secretions from HESN men were more likely to have antibodies (IgA) able to neutralize HIV, and had more innate anti-viral peptides. I therefore propose HIV resistance may be driven by decreased T cell activation in genital tissue, in combination with increased secretion of anti-HIV immune proteins.
Small-signal Dynamic Stability Enhancement Of A DC-segmented AC Power System
Keywords: small-signal stability
HVDC
segmentation

This thesis proposes a control strategy for small-signal dynamic stability enhancement of a DC-segmented AC power system. This control strategy provides four control schemes based on HVDC supplementary control or modification of the operational condition of the HVDC control system to improve the system stability by (i) damping the oscillations within a segment using supplementary current control of a line-commutated HVDC link, based on the model predictive control (MPC) method (control scheme 1), (ii) minimizing the propagation of dynamics among the segments based on a coordinated linear quadratic Gaussian (LQG)-based supplementary control (control scheme 2), (iii) selectively distributing the oscillations among the segments based on a coordinated LQG-based supplementary control (control scheme 3) and (iv) changing the set-points of the HVDC control system in the direction determined based on the sensitivities of the Hopf stability margin to the HVDC links set-points (control scheme 4). Depending on the system characteristics, one or more of the proposed control schemes may be effective for mitigating the system oscillations. Study results show that (i) control scheme 1 leads to damped low-frequency oscillations and provides fast recovery times after faults, (ii) under control scheme 2, each segment in a DC-segmented system can experience major disturbances without causing adjacent segments to experience the disturbances with the same degree of severity, (iii) control scheme 3 enables the controlled propagation of the oscillations among segments and damps out the oscillatory dynamics in the faulted segment, and (iv) control scheme 4 improves the stability margin for Hopf bifurcations caused by various events. Since power system software tools exhibit limitations for advanced control design, this thesis also presents a methodology based on MATLAB/Simulink software to (i) systematically construct the nonlinear differential-algebraic model of an AC-DC system, and (ii) automatically extract a linearized state space model of the system for the design of the proposed control schemes. The nonlinear model also serves as a platform for the time-domain simulation of power system dynamics. The accuracy of the MATLAB/Simulink-based AC-DC power system model and time-domain simulation platform is validated by comparison against PSS/E.
Systemic and Climate Diversity in Ontario’s University Sector
Keywords: Diversity
Ontario
Climate
Systemic
University

The extent and nature of institutional differentiation is a design choice among many that must be considered by policymakers not only when developing a higher education system but also when introducing policy changes to an existing system. Modifications to the design of Ontario’s higher education system have been suggested over the years in an effort to increase its quality (instruction and research) and accessibility in a cost effective manner. The fiscal climate of restraint has recently intensified the debate for structural changes through increased institutional differentiation in Ontario’s higher education system. Institutional diversity was examined using a mixed research method in two phases. This study first used hierarchical cluster analysis which suggested that there has been very little change in diversity between 1994 and 2010 as universities were clustered in three groups for both 1994 and 2010.However, by adapting Birnbaum’s (1983) diversity matrix methodology to Ontario’s university sector, there appears to have been a decrease in systemic diversity (differences in the type of institution and size of institution) and climate diversity (differences in campus environment and culture) between 1994 and 2010 and a projected further decrease to 2018. The second phase of this study used policy analysis and drew on mutually related theoretical perspectives from organizational theory as its primary conceptual framework to interpret and corroborate the decrease in diversity between 1994 and 2010. Interviews were also conducted with university presidents to gain a greater understanding of the key factors or barriers in Ontario’s reticence in proposing design changes in its higher education system. Having been informed by the policy analysis, interviews and projections of the extent of diversity to 2018, the study proposed a diversity policy for Ontario’s university sector. Diversity can be increased in Ontario’s university sector by providing institutions with competitive incremental funding allocations within each of three clusters that would specifically address government diversity objectives through a revised strategic mandate agreement process. Additional research funding should also be provided by the federal government to a limited number of research-intensive universities to ensure that Canadian institutions remain competitive on the world stage.
Implications of Periodic Weak Thermal Stratification in the Epilimnion of Lake Opeongo
Keywords: environmental fluid dynamics
turbulence
stratification

Episodic weak stratification is a persistent and important feature of the epilimnion of Lake Opeongo. Field studies were conducted in Lake Opeongo in 2009 and 2010 to assess the effect of the epilimnetic weak thermal stratification on turbulent mixing and ecological processes. Near surface thermoclines (as defined by dT/dz > 0.2 ̊C m-1 between 1 m and 2 m) occur approximately 20 % of the time and correspond to periods of high values of gradient Richardson number (Rig). Extended periods of near surface stratification (> 1 hr), account for more than 80% of the stratified period. We compare these findings with previous observations from the Experimental Lakes Area and discuss the biological implications of near surface thermoclines. The persistent weak temperature stratification that characterizes the entire epilimnion of Lake Opeongo, acts to reduce the magnitude of turbulent mixing. During these stratified periods, the values of Rig, increase, with a corresponding decrease in the rates of dissipation of turbulent kinetic energy, (ε ), the turbulence activity parameter, I = ε/νN2, and vertical eddy diffusivity (Kz). Mixing during cold fronts occur over time scales of minutes to hours, which work to erode diurnal thermoclines. The direct implications of weak stratification on aquatic organisms are also assessed. The presence of weak stratification also allows for the existence of internal waves within the epilimnion. A key observation in this thesis is the relationship between enhanced small-scale spatial variability in zooplankton distribution and the presence of internal waves in the weakly stratified epilimnion. To quantify this physical-biological coupling, we compare variance of isotherm displacement and gradient Richardson number (Rig) with small-scale spatial distributions of zooplankton. For smaller size ranges of zooplankton (284-450 μm), we find that spatial variability is statistically greatest for the highest values of variability of isotherm displacement. As vertical velocities estimated from wave characteristics are faster than swimming speeds of small zooplankton, these organisms become passively advected by the internal waves leading to increased spatial variability.
Cultural Syndromes and the Appraisal of Common Cancer-related Stressors
Keywords: psychosocial adjustment to cancer
cultural values
stress appraisal
psychometrics

Cultural values provide a system for evaluating situations we encounter; yet, they have seldom been tested in psychosocial oncology. The present research addressed this gap by testing the hypothesis that cancer-related events are stressful because they threaten highly regarded cultural values. As part of a larger study, 417 Western-born Caucasians and 121 Asian-born Chinese immigrants with head and neck cancer (HNC) completed the Individualism-Collectivism Scale (ICS), which measures their endorsement of four cultural syndromes (i.e., vertical-individualism, horizontal-individualism, vertical-collectivism, and horizontal-collectivism). However, the ICS did not tap these constructs identically across these samples. Consequently, I extracted a new common 3-factor measurement model: (a) Camaraderie with Co-workers; (b) Commitment to Family; and (c) Competitiveness. I cross-validated the new model in the HNC samples from which it was derived and in three independent chronic-disease samples. In all cases, results indicated weak invariance. To test the hypothesis, respondents reported the causes of stress (i.e., stressor appraisals) for 24 common HNC-related events. Stressor appraisals reported by a subset of respondents (196 Western-born Caucasians and 44 Chinese immigrants) were categorized based on whether they reflected threats to the cultural values tapped by the new scales. Because only stressor appraisals reflecting threats to commitment to family were identified, I tested the association between commitment to family and the numbers of stressor appraisals reflecting threats to that value. Hierarchical Poisson regression analysis indicated a significant Culture Group x Commitment to Family interaction effect (p = .045): the number of stressor appraisals reflecting threats to commitment to family increased with increasing sense of commitment to family in Chinese immigrants, but not in Western-born Caucasians. Hence, cultural values, in part, explain cross-cultural variation in the experience of cancer stresses. Attention to cultural values can facilitate culturally sensitive patient-centered care by identifying culturally specific causes of stress for targeted psychosocial interventions.