VictorJuiz/thesis huggingface dataset:
Fixing Software Vulnerabilities and Configuration Errors
Keywords: automated patch generation
configuration error
error recovery
machine learning
program analysis
software vulnearbility

With the rise of mobile devices such as smart phones and IoTs and emerging new application areas such as fitness and sport aid, smart home, and augmented reality, computer systems have become a critical part of our daily lives. Our reliance on computer systems make software security and reliability extremely important. However, software security and reliability are threatened by software vulnerabilities and configuration errors. Manually fixing software vulnerabilities and configuration errors is a tedious and time consuming task. Automating the task has gained intense interest. This dissertation addresses three challenges in automating the task: 1) mitigating software vulnerabilities rapidly and safely, 2) generating sound security patches and 3) troubleshooting complex configuration errors that involve dependent configuration settings. We make the following contributions. First, we consider mitigating software vulnerabilities. Inspired by configuration workarounds, a fast alternative of security patches, we design Security Workaround for Rapid Response (SWRR) that works similarly to configuration workaround but has substantially larger coverage than configuration workarounds. We implement a prototype Talos that automatically produces SWRRs and instruments SWRRs into applications. SWRRs generated by Talos can cover 2.1x software vulnerabilities than configuration workarounds. Second, we consider generating sound security patches. With a design specifically targeting three of the most common and severe software vulnerabilities: buffer overflow, bad offset, and integer overflow, we combine program analysis techniques to generate semantically correct security patches. Our prototype implementation called Senx successfully generates correct security patches for 76.2% of 42 real-world software vulnerabilities. Third, we compare the strengths and drawbacks of Talos and Senx qualitatively and quantitatively. On one hand, Senx has the strength in applicability. On the other hand, Talos has the strength in scalability and usability. We find that Talos and Senx have complementary applicability. Combining them, we can address 90.5% of the 42 software vulnerabilities. Finally, we consider troubleshooting and fixing configuration errors involving dependent configuration settings. We leverage unsupervised machine learning to understand the dependency among configuration settings and use automated GUI testing to enable regular users to troubleshoot and fix configuration errors with ease. We implement a prototype called Ocasta and conduct a user study on Ocasta. We find that Ocasta can correctly identify 88.6% of dependent configuration settings and significantly save user time and effort in troubleshooting and fixing configuration errors.
The Lindelof class of L-functions
Keywords: L-functions
Lindelof class
Selberg class
uniqueness theorems
universality
value distribution

Meromorphic functions, called L-functions, play a vital role in number theory. In 1989, Selberg defined a class of L-functions that serves as an axiomatic model for L-functions arising from geometry and arithmetic. Even though the Selberg class successfully captures many characteristics common to most L-functions, it fails to be closed under addition. This creates obstructions, in particular, not allowing us to interpolate between L-functions. To overcome this limitation, V. K. Murty defined a general class of L-functions based on their growth rather than functional equation and Euler product. This class, which is called the Lindelof class of L-functions, is endowed with the structure of a ring. In this thesis, we study further properties of this class, specifically, its ring structure and topological structure. We also study the zero distribution and the a-value distribution of elements in this class and prove certain uniqueness results, showing that distinct elements cannot share complex values and L-functions in this class cannot share two distinct values with any other meromorphic function. We also establish the value distribution theory for this class with respect to the universality property, which states that every holomorphic function is approximated infinitely often by vertical shifts of an L-function. In this context, we precisely formulate and give some evidence towards the Linnik-Ibragimov conjecture.
Identifying New Therapeutics in Experimental Subarachnoid Hemorrhage
Keywords: Aneurysm
Blood-brain barrier
Brain injury
Endothelial
Gene expression
Subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage (SAH) can result in substantial neurologic injury and mortality. Drug clinical trials in SAH over the last several decades have failed to improve clinical outcomes. New therapeutic targets need to be identified and new drug therapies are needed in this patient population. In this thesis, we identified therapeutic agents in SAH by two methods. First, we serendipitously identified the anticonvulsant valproic acid (VPA) as a potential drug treatment in SAH after learning about its beneficial effects in various animal models of neurologic disease. We used VPA treatment in a mouse model of SAH. VPA treatment resulted in improved neurological outcome, decreased brain injury, decreased microthrombi burden, and decreased blood-brain barrier (BBB) disruption. However, retrospective analysis of clinical trial data of SAH patients demonstrated no significant effect of VPA on clinical outcomes. Randomized clinical trials would be needed to determine safety and efficacy of VPA in patients with SAH. Secondly, we focused on one aspect of experimental SAH pathophysiology, BBB disruption, and identified that the time-point with the greatest increase in permeability was at 24 hours after experimental SAH. We subsequently developed and optimized two distinct methods of isolating brain endothelial cells from mice and performed whole-genome expression profiling of these cells. In doing so, we identified potential therapeutic targets and pathways relevant to SAH. Because ‘prostaglandin synthesis and regulation’ was one of the top pathways upregulated and cyclooxygenase-2 (COX-2) was one of the top upregulated genes, we used the selective COX-2 inhibitor, celecoxib, as drug treatment in our SAH model. Celecoxib administration resulted in improved neurological outcome and decreased BBB disruption. Randomized clinical trials with celecoxib are needed. In summary, we have identified two potential therapeutic agents, VPA and celecoxib, that could be investigated further with clinical trials in patients with SAH. Repurposing drugs could provide an important opportunity to improve the outcomes from this devastating disease.
Downlink Transmission and Caching Strategies for Backhaul-Limited Cloud Radio Access Networks
Keywords: backhaul
caching
cloud radio access network
clustering
compression
data-sharing

This thesis considers a downlink cloud radio access network (C-RAN) where all the base stations (BSs) are connected to a central processor (CP) via capacity-limited backhaul links. Two fundamental and different downlink transmission strategies are studied, namely the data-sharing strategy and the compression strategy. In the data-sharing strategy, the backhaul links connecting the CP and the BSs are used to carry user messages; each user's messages are sent to a cluster of BSs, called BS clustering, which locally form the beamforming vectors to cooperatively transmit the messages to the user. In the compression strategy, the user's messages are precoded centrally at the CP, which forwards a compressed version of the analog beamformed signals to the BSs for cooperative transmission. The first part of this thesis focuses on optimizing the data-sharing strategy and the BS clustering while explicitly accounting for the per-BS backhaul capacity limits in each time slot. We show that with the proposed static BS clustering algorithms, the data-sharing strategy can achieve most of the gain brought by the dynamic BS clustering. The second part of this thesis compares the performance of data-sharing and compression strategies from two different perspectives, maximizing the energy efficiency and maximizing the spectral efficiency of the network. From numerical simulations, we observe that although both data-sharing and compression strategies outperform traditional cellular downlink transmission strategies, their comparative performance highly depends on the backhaul capacity. In the final part of this thesis, we study a promising approach to improve the performance of the data-sharing strategy for C-RAN by augmenting the backhaul with BS caching, where the BSs pre-store contents of popular files. We consider a downlink C-RAN consisting of a single cluster of BSs and wireless backhaul channel, and study the optimal cache size allocation strategy among the BSs and the optimal beamforming transmission strategy at the CP such that the users' requested messages are delivered from the CP to the BSs in the most efficient way. We show that more cache sizes should be allocated to BSs with weaker channels and that it is in general not optimal to entirely cache the most popular files first. Numerical results show considerable performance improvement of the optimized cache allocation scheme over the uniform allocation and other heuristic schemes.
Genetic Variation Predicting Lactose Intolerance (LCT -13910C>T), Dairy Intake, 25-Hydroxyvitamin D and Risk of Cardiometabolic Disease
Keywords: Cardiometabolic diseases
lactose intolerance
Nutrigenomics
Plasma proteome

Background: The LCT-13910C>T variant is associated with lactose intolerance (LI) in >70 ethnic populations. In Canada, the prevalence of the LCT -13910C>T variant is not known. Individuals with LI might avoid dairy, which is a rich source of calcium and vitamin D. Dairy has been associated with increased risk of cardiometabolic diseases, but findings have been equivocal. Objectives: To determine the prevalence of LI risk genotypes in major ethnic groups living in Canada and their association with 25(OH)D levels and biomarkers of cardiometabolic disease, and to determine food predictors of calcium and vitamin D in different LCT genotypes. Methods: A total of 1,495 participants from the Toronto Nutrigenomics and Health (TNH) study were used for the present study. Fasting blood samples were obtained for genotyping, 25(OH)D, biomarkers of cardiometabolic disease, and plasma proteomics. Dairy intake was assessed using a 196-item semi-quantitative food frequency questionnaire. Results: Approximately 32% of Caucasians, 99% of East Asians, 74% of South Asians, and 59% of those with other ethnicities had the CC genotype associated with LI. In Caucasians, compared to the TT genotype, those with the CC genotype had lower dairy intake, and plasma 25(OH)D levels. The CT and CC genotypes were associated with lower calcium intake and increased risk of suboptimal (
Intravenous Stromal Cell Therapy for Vascular Protection following Traumatic Spinal Cord Injury
Keywords: Interleukin 10 (IL-10)
Mesenchymal Stromal Cells (MSCs)
Spinal cord injury
Spleen
Stem cells

Traumatic spinal cord injury (SCI) results in devastating chronic impairment and disability. Although there have been many advances in medical management and patient quality of life, a greater understanding of injury pathophysiology will help to tailor treatment options as well as identify novel strategies. Specifically, as mesenchymal stromal cells (MSCs) offer an ethically-sourced, abundant cell type for autologous use, they may be well-suited for SCI. Therefore, this thesis aimed to evaluate the intravenous application of human umbilical cord matrix-derived stromal cells for SCI, comparing the efficacy to that of brain-derived pericytes. Considering the developmental affiliation between MSCs and pericytes, this offers insights to tissue-specific differences in cell function. Further, as the cell therapy effects were linked to the production of interleukin-10 (IL-10) and splenic localization, these components were independently assessed in the context of SCI pathophysiology. While IL-10 deficiency was found to exacerbate acute vascular damage and long-term recovery, the spleen was minimally involved. Nevertheless, the spleen was found to be important in several key stromal cell-mediated effects post-SCI. Together, this work demonstrates that intravenous stromal cell infusion may be a suitable treatment paradigm for acute traumatic SCI, with effects mediated through a rise in systemic and splenic IL-10. Most importantly, it highlights that targeting aspects of the peripheral inflammatory response can translate to changes in the spinal cord.
A Smart IGBT Gate Driver IC with Temperature Compensated Collector Current Sensing
Keywords: IGBT Current Sensing
IGBT Gate Driver IC
Insulated Gate Bipolar Transistors (IGBTs)

Precision current measurement is a critical function that must be incorporated into modern high voltage and high current power systems. Conventional IGBT current sensing methods usually employ discrete sensors such as lossy shunt resistors and involve accessing the high voltage collector load of the IGBT. This would normally present difficulties for integration. In this thesis, an IGBT collector current sensing technique which only utilizes the low voltage signal at the gate terminal is presented. This technique is based on the unique Miller plateau relationship between the gate current and collector current (IG and IC) for a particular gate resistance (RG), and allows for a cycle by cycle measurement of IC during both turn-on and turn-off transients. This technique is theoretically verified, experimentally demonstrated and integrated into an IGBT gate driver IC. The presented gate driver IC has a highly configurable gate driver, an on-chip CPU for local data processing and an integrated current sensor. This IC is prototyped using TSMC 0.18µm BCD Gen-2 process. A polynomial curve fitting is implemented by the on-chip CPU to predict IC based on the digitized IG value. Measurements using a double pulse test setup at room temperature show that an accuracy of ±1 A could be ensured with a 2nd order polynomial curve fitting, within the current range between 1 to 30 A for turn-on and 1 to 50 A for turn-off. After the temperature effect is analyzed and factored in, a 3rd order polynomial curve fitting is implemented, an estimated accuracy of ±0.5 A could be achieved within the current range of 1 to 30 A for turn-on and 1 to 50 A for turn-off from 25 to 75 oC.
FROM TEACHER TO LEARNER AND BACK AGAIN: A NARRATIVE INQUIRY INTO TEACHER VOICE IN PROFESSIONAL LEARNING
Keywords: authentic
experienced teachers
knowledge
narrative
Ontario
professional learning

FROM TEACHER TO LEARNER AND BACK AGAIN: A NARRATIVE INQUIRY INTO TEACHER VOICE IN PROFESSIONAL LEARNING Doctor of Philosophy 2018 Lena A. Glaes-Coutts Graduate Department of Curriculum, Teaching and Learning University of Toronto Abstract My research investigates how four experienced Ontario elementary teachers use their personal and professional knowledge to define what they consider to be personal, purposeful and relevant professional learning, or authentic professional learning (Mockler, 2013; Webster-Wright, 2009). Authentic learning is here understood to represent what the teachers themselves described as their lived experiences of ongoing professional learning, and what they identified as relevant and purposeful for their continued professional, as well as personal learning. I used a narrative approach, which takes a situated, holistic perspective in examining teachers’ lived experience and motivation for engaging in professional learning (Webster-Wright, 2009). The primary rationale for using narrative inquiry is to construct narratives of how experienced teachers describe authentic learning in the test-driven environment that dominates the Ontario educational climate today. It is important to cultivate a trust in what the teachers express. In honouring their voices, we may develop a deeper understanding of their perspective, as teachers’ professional learning is an important element of how teachers merge new knowledge with their professional practice for the purpose of improving student learning. I found that these experienced teachers seek out learning opportunities that honour their professional knowledge, integrity, and identity. While looking for a sense of autonomy in their learning they also expressed a desire to work with other experienced teachers in order to collaborate, communicate and construct new learning. As experienced teachers are a rich resource, capable of building up the educational profession in Ontario, it is vital for the educational system to capitalize on the professional capital, wisdom, and knowledge of experienced teachers. This method of understanding professional learning through the lens of experienced teachers proffers an alternative approach to gaining a deeper understanding that constitutes authentic professional learning for them.
Stories of Spirit and the streets: Indigenous mental health, trauma, traditional knowledge and experiences of homelessness
Keywords: homelessness
Indigenous
mental health
traditional knowledges
trauma

Indigenous people in Canada have endured many traumas as a result of the consequences of colonization observed through poor social determinants of health. Homelessness, particularly, has been noted as at a state of crisis for Indigenous people. This study seeks to understand the intersections of homelessness, traditional knowledge and mental health by interviewing sixteen Indigenous homeless people in a large Canadian city. Results revealed some psychological factors, cultural identity and external factors as being integral in the overall experiences of homelessness. The results of this study help identify a need for integrative mental health services that focus on the Indigenous culture as a strength in the promotion of healing and recovery. Specific implications are inclusive of policy and psychological approaches that are based on the needs of Indigenous homeless peoples themselves that can build and improve the current models of mental health care that embrace the Indigenous approaches to mental health and trauma. These results also provide some rich data regarding the actual lived experiences of marginalized people that have been silenced by recognizing the importance of cultural connection and the utilization of Indigenous approaches in the field of mental health and trauma service.
Royal Harem Lives: Power, Intimacy, and Liminal Family Formation In the Late-19th Century Qajar Court
Keywords: gender
harem
Iran
Qajar
women

Royal Harem Lives explores the social, spatial and cultural dimensions of the women’s quarter of Nasir al-Din Shah’s court, variously referred to as his harem or andarun, during his reign (1848-1896). While this period is generally understood to coincide with the emergence of modernity in Iran, the maintenance of a large-scale royal harem is generally associated with a traditional and outdated Islamic convention. As such, the expansion of the Gulistan harem in the second half of the 19th century, concurrently with greater contact between the Qajar empire and Western modernity, presents us with an interesting paradox. This dissertation will focus on the demographic, physical, topographic, and representational dimensions of Nasser al-Din Shah’s harem, and the various social and familial relations within it, to argue that this institution was in fact one of the central loci of negotiations with modernity in late 19th century Iran. Throughout the following chapters, I examine the complex structure of this institution and the everyday life of its residents—at various points estimated to be between 700 and 2000 wives and female relatives, as well as different classes of employees¬—from physicians and translators, to servants, maids, slaves, and eunuchs. For its time, the cultural and ethnic heterogeneity within the Gulistan harem was quite unique, as it housed residents from various interregional networks, and hosted elite local and international visitors. Located within the ever-expanding Gulistan Palace, and in the heart of the Qajar capital, the Gulistan harem was physically and socially structured around a set of extremely rigid hierarchies, which were often undermined by various affective bonds, developed through relations of proximity and cunning negotiations. I explore a number of these complex relationships and the ways in which they informed familial association, court life, and the distribution of political power within the late Qajar Empire.
Branching Program Lower Bounds
Keywords: Branching Programs
Computational Complexity
Function Composition
LogSpace vs PolyTime
Space Complexity
Time Space Trade-offs

A longstanding open problem in complexity theory is whether the class Polytime (P) is the same as LogSpace (L) or nondeterministic LogSpace (NL). In this thesis, we explore this problem by studying time/space tradeoffs for problems in P . As in, for some natural problem in P , does the addition of a space restriction prevent a polynomial time solution ? To begin, we prove exponential lower bounds on the size of a restricted model of branching programs called semantic read-once 3-ary nondeterministic branching programs solving a polytime computable function, in particular the polynomial evaluation problem. In the second part, we prove lower bounds against branching programs solving Function Composition. In particular, we show that the amount of space required for computing the composed function grows as is seen in the straight forward algorithm (where space grows additively). If shown true for general branching programs, this would separate L and P. We show this is indeed true in the restricted setting of nondeterministic read once branching programs, for the syntactic model as well as the stronger semantic model. We prove that such branching programs for solving the tree evaluation problem over an alphabet of size 'k' requires size roughly k^{Omega(h)}, i.e space Omega(h log k) where 'h' is the number of compositions. Then we focus entirely on general branching programs sticking to the theme of lower bounds against function composition. We give a better lower bound than is possible by using Nechiporuk's method for k-way branching programs solving a specific composition problem. Using essentially the same method we give a matching lower bound to that achievable by using Nechiporuk's method for binary branching programs. Any marginal improvement here would be consequential towards beating Nechiporuk's method for binary branching programs, a longstanding open problem. We then proceed to give some surprising upper bounds based on communication complexity protocols that are different from naive upper bounds. Our aim here is to improve our understanding of a possible approach to prove the suspected lower bound just mentioned, but the connections to communication complexity therein might themselves be of independent interest.