VictorJuiz/thesis huggingface dataset:
Unobtrusive Storage Maintenance

Storage systems rely on maintenance tasks, such as backup and defragmentation, to provide a multitude of guarantees that range from data availability and security, to good performance. These tasks access large amounts of data and can significantly impact foreground applications. The work presented as part of this thesis outlines the challenges of storage maintenance and provides mechanisms that lower its impact, allowing it to be performed more efficiently. Maintenance operations act as insurance for storage systems. To avoid the prohibitive cost incurred in their absence, storage operators pay the price of performing them periodically. In the case of reliability, for example, we find that the error characteristics of hard disk drives in Google's data centers are diverse across models and operating environments. Due to this unpredictability, the use of periodic maintenance becomes unavoidable. Furthermore, recent research efforts on disaster prediction depend on metrics collected through periodic maintenance operations. Unfortunately, periodic storage maintenance requires data to be accessed multiple times. As a case in point, we find that customers of Symantec and Veritas schedule backups multiple times a week. This often results in excess maintenance work that fails to complete within the scheduled downtime periods. At this point, foreground workload impact becomes unavoidable in order to maintain the same reliability guarantees. To lessen this impact, maintenance I/O can be scheduled only when storage devices are otherwise idle. To achieve this, idleness must be predicted accurately. Fortunately, our extensive study of disk workloads reveals characteristics that allow idleness to be predicted accurately by simple models. Given the number of maintenance tasks available today, idle time can prove insufficient. For such scenarios we present Duet, a framework that provides notifications to tasks about relevant changes in the system cache. Using this mechanism, tasks can reduce their I/O by prioritizing processing of cached data. Data can be cached either due to other maintenance tasks requesting it previously, or due to overlapping foreground I/O activity. In other words, tasks running concurrently can implicitly collaborate, collectively reducing the I/O required for maintenance and, by extension, the idle time needed to execute it.

Keywords: File Systems
Maintenance
Operating Systems
Storage Performance
Storage Reliability
Storage Systems
Advisor: Goel, Ashvin
Demke Brown, Angela
The Triangle Arts Trust: Contemporary - Art and Transnational Production

This dissertation presents a historical overview and contemporary analysis of the Triangle Arts Network, an international network of artists and arts organizations that promotes the exchange of ideas and innovation within the contemporary arts. It was established in 1982 through a workshop held in Pine Plains, New York and quickly grew into an international network of artist led workshops around the world. More than twenty years later the network continues to grow and includes a roster of ongoing workshops as well as artist led organizations and centres. This dissertation situates Triangle as a major global phenomenon, yet one that operates outside the mainstream artscapes. My research follows the networkâ s historical links from Saskatchewan, Canada, to New York and onto South Africa. This web-like evolution demonstrates the complexity of global art networks and the fluidity of boundaries needed for contemporary art discourse. This research explores how the movement of ideas, artists and infrastructures complicate our understanding of clearly defined boundaries within contemporary art and globalization. Using Actor-Network Theory (ANT) as a metaphor for the Triangle Network, I attempt to unpack the complexities of an art system without objects, a process without product and the entangled relationships between artists, workshops and grassroots models of production.

Keywords: Canadian Art
Contemporary Art
Globalism
Modern Art
South African Art
Transnationalism
Advisor: Harney, Elizabeth
Steam Cured Self-Consolidating Concrete and the Effects of Limestone Filler

The purpose of this thesis is to determine the effect and the mechanisms associated with replacing 15% of the cement by limestone filler on the mechanical properties and durability performance of self-consolidating concrete designed and cured for precast/prestressed applications. This study investigates the role of limestone filler on the hydration kinetics, mechanical properties (12 hours to 300 days), microstructural and durability performance (rapid chloride permeability, linear shrinkage, sulfate resistance, freeze-thaw resistance and salt scaling resistance) of various self-consolidating concrete mix designs containing 5% silica fume and steam cured at a maximum holding temperature of 55°C. This research also examines the resistance to delayed ettringite formation when the concrete is steam cured at 70°C and 82°C and its secondary consequences on the freeze-thaw resistance. The effect of several experimental variables related to the concrete mix design and also the curing conditions are examined, namely: limestone filler fineness, limestone filler content, cement type, steam curing duration and steam curing temperature. In general, the results reveal that self-consolidating concrete containing 15% limestone filler, steam cured at 55°C, 70°C and 82°C, exhibited similar or superior mechanical and transport properties as well as long term durability performance compared to similar concrete without limestone filler. When the concrete is steam cured at 55°C, the chemical reactivity of limestone filler has an important role in enhancing the mechanical properties at 16 hours (compared to the concrete without limestone filler) and compensating for the dilution effect at 28 days. Although, at 300 days, the expansion of all concrete mixes are below 0.05%, the corresponding freeze-thaw durability factors vary widely and are controlled by the steam curing temperature and the chemical composition of the cement. Overall, the material properties indicate that the use of 15% limestone filler as cement replacement is a viable option for the precast/prestressed concrete applications, and in addition, would also have economic and environmental benefits.

Keywords: Delayed Ettringite Formation
Durability
Early Age Strength
Limestone
Precast Concrete
Steam Curing
Advisor: Panesar, Daman
Peterson, Karl
Aspects typologiques de l'alternance de codes: les paires de langues russe/anglais et russe/français

Since the 1970s, grammatical constraints proposed to account for forms and sites of code-switching (CS) have been numerous. They differ in which observed behaviours they account for. Muysken (2000) reconciles many contradictions by suggesting, instead of one model for all language pairs, three CS patterns : insertion, alternation, and congruent lexicalization. Each is governed by different constraints and linked to numerous factors, linguistic and social, that characterize bilingual situations. He suggests a diagnostic tool of 27 criteria to identify the three patterns. These feature sets need to be more precisely defined to allow testing. This thesis aims to optimize these definitions to establish a quantitative profile for the identification of two patterns (insertion, alternation). It evaluates the effects of linguistic typology on differentiation of two types of CS. For these purposes, two conversational corpora, collected from six Russian/English and four Russian/French bilinguals (all dominant in Russian) were recorded, transcribed and analyzed (38,512 words). The CS patterns are analyzed in terms of language variation : insertion and alternation are each separately considered as the dependent variable. 21 diagnostic factors (derived from Muyskenâ s original 27) operate as independent linguistic variables. Each factor conditions, to different degrees, the choice between variants of the dependent variable. Thus, each CS type is quantitatively defined according these diagnostic features and redefined by the multiple regression analysis (1,793 tokens). The 11 diagnostic criteria which play a significant role in selection between insertion and alternation play different roles for the two CS patterns, allowing the establishment of a hierarchy of their relative predictive power. I argue that there is a correlation between the importance of diagnostics features and the typological distance between the languages. Insertion is more sensitive to typological effects than alternation. The typological differences between the languages is important when the dominant pattern is insertion and but not for alternation. Specifically, the relative morphological complexity of Russian and French prevents morphological integration and leads to frequent omissions of some elements. The two CS types differently react to the typological distance : Russian and English share more linearly equivalence, thereby decreasing syntactic conflict and enabling more possibilities to switch.

Keywords: alternation
code-switching
insertion
language contact
typology
Advisor: Brousseau, Anne-Marie
Nagy, Naomi
Card Carrying Christians: Credit, Debt, and Believing in Emerging Colombia

This dissertation addresses the entanglements of Christianity and financializing capitalism in Colombia, South America. At its most empirical, this dissertation details ethnographically the debt upon which the Gospel of Prosperity rests. The ethnographic research, collected over two and a half years of sustained fieldwork, assesses Colombiaâ s largest mega-church, a Protestant micro-credit program in BogotĂĄ, various commercial banks, a rural Pentecostal community, and a multi-level marketing company. Together, this evidence establishes that financializing capitalism in Colombia depends upon a Christian morality. The evidence also makes possible the dissertationâ s more theoretical claim: that credit is a matter of belief. The argument begins with some reflection on the etymological fact that both words, credit and belief, share the same Latin root, credere, but then leans on participant observation, extended interviews, and life narratives to demonstrate how credit has become a matter of belief at the level of lived experience in Colombia.

Keywords: Belief
Christianity
Colombia
Credit
Debt
Finance
Advisor: O'Neill, Kevin L
Placental Pharmacology -- Implications for Therapy in Pregnancy

Medication use during pregnancy requires a balance between treating a condition in the mother, and minimizing potential risks in the fetus. In recent years, it has been estimated that between 50 and 70% of pregnant women in North America will take at least one prescription medication during their pregnancy. The decision to begin or continue treatment during pregnancy relies heavily on evaluating the risk-benefit ratio, and an important determinant in this risk assessment is estimating fetal drug exposure. The use of medications in pregnant women can be especially challenging, as there is very limited safety data in pregnancy. Recently, novel oral anticoagulants have been developed and approved for clinical use. However, the information regarding their fetal safety and placental transfer in humans is unknown. We used the ex vivo placenta perfusion model to investigate anticoagulant (dabigatran, rivaroxaban, apixaban) transfer across the human placenta. Rivaroxaban and apixaban rapidly crossed the term human placenta, while dabigatran crossed the placenta to a lesser extent. The placenta perfusion results were adjusted to account for protein binding and pH differences between the mother and fetus. We also developed a pharmacokinetic model that adequately described the transplacental transfer of anticoagulants by using data from our experiments. While the placenta perfusion model can be technically challenging, its results strongly correlate with in vivo placental transfer data. By evaluating the success rate of the perfusion model in our laboratory, we determined that establishing the fetal circulation is an important stage of the protocol. This information can be used to create a focused training program to help increase the overall success rate of this model and productivity of the lab. Drug use in pregnancy is multifactorial, and placental transfer data is important in assessing which drugs can be used to treat the mother while protecting the unborn.

Keywords: anticoagulants
drug safety
placenta
pregnancy
Advisor: Ito, Shinya
The Equivariant K-Theory of Commuting 2-tuples in SU(2)

In this thesis, we study the space of commuting n-tuples in G = SU(2), Hom(Zn, SU(2)). We describe this space geometrically via providing an explicit G- CW complex structure, an equivariant analog of familiar CW- complexes. For the n = 2 case, this geometric description allows us to compute various cohomology theories of this space, in particular the G-equivariant K-Theory KG*( Hom(Z2, SU(2))), both as an R(SU(2))-module and as an R(SU(2))-algebra, where R( SU(2)) denotes the representation ring of SU(2). This space is of particular interest in the study of quasi-Hamiltonian spaces M, which come equipped with a moment map that takes values in the Lie group, &phis; : M → G. For the specific example M = G × G with moment map given by the commutator map, &phis;–1( e) = Hom(Z2, G). Finite dimensional quasi-Hamiltonian spaces have a bijective correspondence with certain infinite dimensional Hamiltonian spaces, and we compute relevant components of this larger picture in addition to &phis; –1(e) = Hom(Z 2, SU(2)) for this example.

Keywords: Algebraic topology
Equivariant K-theory
quasi-Hamiltonian systems
Advisor: Selick, Paul
Jeffrey, Lisa
Understanding How the Student Success Strategy Has Developed and Contributed to Student Outcomes in One Ontario District

In 2003 the Ontario Ministry of Education launched the Student Success Strategy, a game changing initiative of whole system reform. Since that time Ontario’s graduation rate has risen from 68% to 85.5% by 2015, but surprisingly few studies have examined the strategy. The purpose of this study was to better understand how the Student Success Strategy developed and contributed to student outcomes in one school district. A qualitative research approach was used for the study, which was also complemented by administrative data. Schools which would be considered were identified using a purposeful sampling technique. Qualitative data was derived from interviewing educators who were members of their schools’ Student Success Team. Interview questions were focused on four key pillars of the strategy: efforts at connecting with students, providing programs that enable achievement, improving teaching and learning, and connecting with the community. Administrative data originated from Ontario’s Education Quality and Accountability Office test scores, as well as district and Ministry reports. Six key findings from the study emerged. The first revealed that fostering positive connections with secondary students takes time, requiring a multi-tiered differentiated approach involving layers of interventions and support. The second finding demonstrated that improving the range of programs, notably the Specialist High Skills Major, led to an enrolment surge and improved academic performances. The third main finding confirmed on-going efforts at improving teaching and learning, and the critical role administrators play as instructional leaders driving improvements. The fourth finding noted mixed results in connecting with the community, with no gains in engaging parents, however gains were made in accessing community supports for students as well as through dual-credit opportunities with positive post-secondary outcomes. The fifth finding revealed strong commonalities on how the Student Success Strategy had developed over time. The sixth key finding exposed the challenges connected to the strategy, notably replacing key staff, and the desire to retain greater school autonomy. What clearly was unquestionable was the impact policy, programs, and people – both within the school and community - could have in connecting with students, meeting their varied and individual needs, including pathways for their future success.

Keywords: Disengagement
Engagement
Partnerships
Programs
Student Success
Teaching and Learning
Advisor: Ryan, James
Mechanism of Claudin Regulation in Kidney Tubular Epithelial Cells

Abstract The overall objective of my studies was to gain insight into the role and regulation of claudin family tight junction (TJ) proteins in kidney tubular cells. Members of the claudin family generate specific paracellular pathways and thus control epithelial permeability. Each claudin has different properties. However, their regulation is incompletely understood. The inflammatory cytokine Tumor Necrosis Factor-α (TNF- α) is a key pathogenic factor in kidney disease and is also known to alter TJ permeability. Therefore, my first objective was to explore how TNF-α alters claudin expression and to correlate the findings with permeability changes. TNF-α altered the expression of several claudins in cultured tubular cells. We described a novel biphasic effect of TNF-α on claudin-2, a leaky channel TJ protein. TNF-α elevated claudin-2 expression after short-term (1–6 h) and reduced it after long-term treatment through distinct mechanisms. The early increase was due to reduced degradation of claudin-2 mediated by theEGF receptor, ERK, RhoA and Rho kinase. In contrast, prolonged TNF-α treatment reduced claudin-2 synthesis. Moreover, JNK was involved in both effects. Second, ERK and JNK also mediated an increase in claudin-1, 4 and 7 induced by prolonged TNF-α treatment. To explore the role of altered claudin expression we measured TNF-α-induced transepithelial resistance (TER) changes. TNF-α caused an initial decrease and a late increase in TER. Inhibition of ERK and JNK as well as silencing of claudin-2 reduced the second phase (TER increase). In summary these studies suggest a strong causal connection between TNF-α-induced changes in claudin expression and permeability. My second objective was to study how claudin-2 expression is controlled in unstimulated epithelial cells. I found that Cldn-2 expression increased with cell confluency, and was also controlled by the small GTPases RhoA and Rac, key regulators of junction assembly and cytoskeleton. Rho silencing increased Cldn-2 expression, while Rac was required for maintaining Cldn-2 levels. Further, claudin-2 expression also required NFκB and PI3 kinase. These studies point to exciting novel modes of claudin-2 expression regulation. Since claudin-2 also affects proliferation and migration, these findings could have relevance to acute and chronic kidney disease as well as cancer.

Advisor: Szaszi, Katalin
A Computational Model of the Acquisition of Mental State Verbs

Children first use verbs to refer to inner mental states, such as thoughts and beliefs, only towards their 4th birthday. Presenting this ability serves as important evidence of the stage of cognitive development of a child since it entails an ability to conceptualize mental states. This developmental milestone is necessary for children to engage in social interaction since appropriate interaction relies on directing the interaction and anticipate actions surrounding them given the mental states of others. Thus far, psycholinguistic models have been widely focused on the development of cognitive and linguistic skills required to enable the expression of mental states by children. However, while computational models have proved to be a useful tool in studying the developmental trajectory of similar language acquisition phenomena, no computational model to our knowledge has been used to analyze the linguistic development required for the expression of mental states. In this thesis, I present a computational model used to analyze the way linguistic development plays a role in learning to express mental state verbs. The computational model in this thesis offers an integrated framework that simultaneously models several of the cognitive and linguistic factors in the acquisition of mental state verbs. The cognitive factor simulates the difficulty in attending to mental states, while the linguistic properties represent the typical semantic and syntactic properties of use of mental state verbs, e.g., reference to mental states using a sentential complement syntactic structure. The experimental work in this thesis replicates psycholinguistic observations from the child acquisition of mental state verbs. The results of these experiments shed light on the facilitating role of certain linguistic properties of mental state verbs in learning to verbally refer to mental meanings. Importantly, I achieve these results within the context of naturalistic language input that mimics the complexity and diversity of use of mental state verbs and verbs from additional semantic classes in child-directed speech. Finally, I present a novel extension to an existing computational model of verb argument structure learning that enables the simultaneous and incremental learning of verb classes. The novel model offers a probabilistic framework to analyze monotonically growing verb classes in comparison to previously offered batch models that limit the capabilities of the computational simulation. Moreover, this model gives support to the importance of an additional linguistic property of mental state verb, i.e., the role of their use with syntactic structures other than the well-studied co-occurrence with sentential complement syntax in child-directed speech. Finally, I show the contribution of this novel computational component in comparison with previous computational models in a wider context of argument structure learning.

Keywords: Bayesian models
Cognitive modeling
Computational Linguistics
Mental state verbs
verb acquisition
Advisor: Stevenson, Suzanne