VictorJuiz/thesis huggingface dataset:
Design of Optimal Strictly Positive Real Controllers Using Numerical Optimization for the Control of Large Flexible Space Structures

The design of optimal strictly positive real (SPR) compensators using numerical optimization is considered. The plants to be controlled are linear and nonlinear flexible manipulators. For the design of SISO and MIMO linear SPR controllers, the optimization objective function is defined by reformulating the H2-optimal control problem subject to the constraint that the controllers must be SPR. Various controller parameterizations using transfer functions/matrices and state-space equations are considered. Depending on the controller form, constraints are enforced (i) using simple inequalities guaranteeing SPRness, (ii) in the frequency domain, or (iii) by implementing the Kalman-Yakubovich- Popov lemma. The design of a gain-scheduled SPR controller using numerical optimization is also considered. Using a family of linear SPR controllers, the time dependent scheduling signals are parameterized, and the objective function of the optimizer seeks to find the form of the scheduling signals which minimizes the manipulator tip tracking error while minimizing the control effort.

Keywords: passivity-based control
SPR transfer functions/matrices
robust optimal control
numerical optimization
flexible structures
Advisor: Damaren, Christopher John
Analysis of Diffusion MRI Data in the Presence of Noise and Complex Fibre Architectures

This thesis examines the advantages to nonlinear least-squares (NLS) fitting of diffusion-weighted MRI data over the commonly used linear least-squares (LLS) approach. A modified fitting algorithm is proposed which accounts for the positive bias experienced in magnitude images at low SNR. For b-values in the clinical range (~1000 s/mm2), the increase in precision of FA and fibre orientation estimates is almost negligible, except at very high anisotropy. The optimal b-value for estimating tensor parameters was slightly higher for NLS. The primary advantage to NLS was improved performance at high b-values, for which complex fibre architectures were more easily resolved. This was demonstrated using a model-selection classifier based on higher-order diffusion models. Using a b-value of 3000 s/mm2 and magnitude-corrected NLS fitting, at least 10% of voxels in the brain exhibited diffusion profiles which could not be represented by the tensor model.

Keywords: Diffusion tensor imaging
Magnetic Resonance Imaging
Complex fibres
spherical harmonics
generalized tensors
magnitude bias
high b-values
Advisor: Stanisz, Greg
Oral Health Status and Treatment Needs of the Institutionalized Chronic Psychiatric Patients in two Ontario Psychiatric Care Centres

Oral Health Status and Treatment Needs of the Institutionalized Chronic Psychiatric Patients in two Ontario Psychiatric Care Centres Neyaz Farrahi-Avval Master of Science Graduate Department of Dentistry University of Toronto 2008 Abstract Purpose: To examine the oral health status of psychiatric in-patients at two long-term psychiatric health centres, with one operating a full-time dental care facility. Methods: Data were gathered from clinical examinations, a structured interview and hospital records from 120 participants. Periodontal (CPI) and dental (DMFT) indices, subjectively reported oral health status, and oral health behaviour were subsequently analyzed. Results: Referrals for dental problems were made for 62.9% of participants. Bivariate analyses revealed positive correlations between DMFT scores, age and length of stay. Multiple regression analyses demonstrated correlations between DMFT scores and infrequent dental visits, frequent snacking and age. Patients at the psychiatric hospital without a full-time dental care facility were more likely to have had higher DMFT scores, and infrequent dental visits. Conclusions: Psychiatric patients have poor oral health and significant oral health treatment needs. This study underlines the need for on-site dental care facilities at long-term psychiatric care centres.

Keywords: Oral Health
Chronic Psychiatric Patients
Treatment Needs
Dental Caries
Hospital Dental Care
Institutionalization
Bipolar
Schizophrenia
Affective Disorder
Oral Hygiene
Dentistry
Canada
DMFT
CPI
Advisor: Locker, David
Rebelling against Discourses of Denial and Destruction: Mainstream Representations of Aboriginal Women and Violence; Resistance through the Art of Rebecca Belmore and Shelley Niro

Violence against Native women in Canada is widespread and has deeply systemic and colonial roots. This paper will attempt to show the role that dominant representations of culture, race, and gender have in allowing this violence to continue by eclipsing many different narratives and ways of expressing cultural and individual identities. Violence in the mainstream media will be explored and analyzed drawing on concepts from critical theories, Aboriginal epistemological frameworks, and anti-racist, disability, and Afro-centric feminisms to build a framework on which to analyze the meanings of the representations. After exploring violent and colonial discourse, the discussion will turn to art. Self and cultural representation and expression by Native women can act as important forms of resistance to the tools of colonial oppression. The artwork of Rebecca Belmore and Shelley Niro are powerful examples of addressing and exploring issues of identity, culture, resistance, and survival for Aboriginal women.

Keywords: Native women, Aboriginal women, violence, Shelley Niro, Rebecca Belmore, discourse, mainstream media, art, resistance, colonialism, decolonization
Advisor: Chambon, Adrienne S.
Relationship Between Sensorineural Hearing Loss and Vestibular and Balance Function in Children

Similarities between the peripheral auditory and vestibular systems suggest that children with sensorineural hearing loss (SNHL) may demonstrate vestibular and balance impairments. This hypothesis was studied in 40 children with severe to profound SNHL and unilateral cochlear implants (CI). Vestibular function was assessed with caloric, rotational, and vestibular evoked myogenic potential (VEMP) testing; balance was assessed with standardized static and dynamic tests. Horizontal semicircular canal function was abnormal in 53% (17/32) with caloric, and 39% (14/36) with rotational stimulation. Saccular function was absent bilaterally in 5/26 (19%) and unilaterally in 5/26 (19%) with VEMP. Balance abilities were significantly poorer (μ=12.9±5(SD)) than normal hearing controls (μ=17±5(SD); p=0.0006) and correlated best with horizontal canal function from rotational stimulation (p=0.004;R2=0.24). SNHL from meningitis was associated with worse balance function than other etiologies. Vestibular and balance dysfunction occurred in >1/3 of children with SNHL and CI, and is highly dependent on etiology.

Keywords: Vestibular Function
Sensorineural Hearing Loss
Cochlear Implantation
Pediatric
Advisor: Gordon, Karen A.
Acculturation Strategies and its Effect on Depressive Symptoms in the Brazilian Immigrant Community in the Greater Toronto Area

Among several difficulties associated with immigration, acculturation process has been recognized as one of the main stressors and one of the major risk factors associated in the incidence of mental disorders. The strategies adopted by individuals to deal with the acculturation process appear to be predictive of different mental health outcomes. This exploratory study investigated the relationship between acculturation strategies and the occurrence of symptoms of depression in the context of the Brazilian immigrant community living in the Greater Toronto Area. The results demonstrated that Separation and Assimilation were the predominant strategies for this sample and that acculturation strategies failed to serve as significant predictors of depression scores. However, participants with Separation as their predominant acculturation strategy exhibited higher depressive symptom endorsement. The significance of these findings in the context of previous research as well as its implications for future research and critical multicultural practice in mental health are discussed.

Keywords: Acculturation Strategies
Depressive Symptoms
Immigration
Brazilian Immigrants
Critical Multicultural Counselling
Mental Health Promotion
Advisor: Moodley, Roy
Adhesive Bonding of Concrete-steel Composite Bridges by Polyurethane Elastomer

This thesis is motivated by the use of full-depth, precast, prestressed concrete panels to facilitate deck replacement of composite bridges. The shear pockets required in using convention shear stud connections, however, can cause durability problems. The objective of this study is to investigate the possibility of eliminating the use of shear studs, and adhesively bond the concrete and steel sections. The feasibility of the developed polyurethane adhesive joint is defined based on the serviceability and ultimate limit states. The joint must have sufficient stiffness that additional deflection due to slip must not be excessive. The adhesive and bond must also have sufficient strength to allow the development of the full plastic capacity of the composite section. The use of the developed adhesive joint in typical composite bridges was found to be feasible. The behaviour under live load was found to be close to a fully composite section.

Keywords: Composite Bridge
Adhesive Bonding
Polyurethane Elastomer
Raid Deck Replacement
Advisor: Gauvreau, Douglas Paul
Next Generation Lanthanide-based Contrast Agents for Applications in MRI, Multimodal Imaging, and Anti-cancer Therapies

A new class of polymer stabilized gadolinium trifluoride nanoparticles (NPs) have been developed as contrast agents for magnetic resonance imaging (MRI) and computed tomography (CT), with potential long term goals in targeted imaging and anti-cancer therapy. The NPs are comprised of a 90/10 mixture of GdF3/EuF3 and are coated with linear polyacrylic acid (PAA) chains consisting of 25 repeating units. The resulting aggregates are stable in serum and possess unprecedented mass relaxivities [i.e. ~100-200 s-1(mg/mL)-1]. Electron microscopy images reveal various NP morphologies which depend on the exact synthesis protocol. These include highly cross-linked oblong clusters with 30-70 nm cross sections, extensively cross-linked aggregates with 100-300 nm cross sections, and distinct polymer stabilized nanocrystals with 50 nm diameters. Their application as contrast agents in T1-weighted MRI studies, CT imaging at various X-ray energies, and preliminary rat brain perfusion studies was also tested. NP contrast enhancement was compared to Gd-DPTA (Magnevist®) and iopramide (Ultravist 300®) to demonstrate their high contrasting properties and potential as multimodal contrast agents.

Keywords: gadolinium
MRI
nanoparticle
imaging
contrast agent
relaxivity
Advisor: Prosser, Robert Scott
Microarchitecture and FPGA Implementation of the Multi-level Computing Architecture

We design the microarchitecture of the Multi-Level Computing Architecture (MLCA), focusing on its Control Processor (CP). The design of the microarchitecture of the CP faces us with both opportunities and challenges that stem from the coarse granularity of the tasks and the large number of inputs and outputs for each task instruction. Thus, we explore changes to standard superscalar microarchitectural techniques. We design the entire CP microarchitecture and implement it on an FPGA using SystemVerilog. We synthesize and evaluate the MLCA system based on a 4-processor shared-memory multiprocessor. The performance of realistic applications shows scalable speedups that are comparable to that of simulation. We believe that our implementation achieves low complexity in terms of FPGA resource usage and operating frequency. In addition, we argue that our design methodology allows the scalability of the CP as the entire system grows.

Keywords: Computer architecture
FPGA applications
Microarchitecture
Parallelism
Embedded systems
Multi-core systems
Advisor: Abdelrahman, Tarek S.
Placement By Marriage

As the field programmable gate array (FPGA) industry grows device capacity with Moore's law and expands its market to high performance computing, scalability of its key CAD algorithms emerges as a new priority to deliver a user experience competitive to parallel processors. Among the many walls to overcome, placement stands out due to its critical impact on both frontend synthesis and backend routing. To construct a scalable placement flow, we present three innovations in detailed placement: a legalizer that works well under low whitespace; a wirelength optimizer based on bipartite matching; and a cache-aware annealer. When applied to the hundred-thousand cell IBM benchmark suite, our detailed placer can achieve 27% better wirelength and 8X faster runtime against FastDP, the fastest academic detailed placer reported, and our full placement flow can achieve 101X faster runtime, with 5% wirelength overhead, against VPR, the de facto standard in FPGA placements.

Keywords: Design Aids
Placement
Algorithm
Scalability
Advisor: Zhu, Jianwen
Forest Certification in Brazil: Choices and Impacts.

The challenges faced by the Brazilian forest industry dealing with the natural forests and plantations have provided favourable ground for the establishment of forest certification. This study presents the first investigation of the two certification systems (FSC and Cerflor) in Brazil from the private sector perspective. Through an exploratory factor analysis (EFA), market, learning, and signaling were validated as governance mechanisms of forest certification in Brazil. The results from the importance and performance analysis (IPA) indicated that companies did not see any return in terms of a better price for certified products; however, they demonstrated high satisfaction with the performances of non-economic benefits. Descriptive statistics revealed external pressures influencing companies to pursue forest certification and overall accomplishments of certification from economic, social and ecological points of view. Finally, suggestions for future research and conclusions are made in order to provide information for the industry, certification systems, and the Brazilian government.

Keywords: Forest Certification
Brazil
FSC
Cerflor
Advisor: Kant, Shashi
Robust Subject Recognition Using the Electrocardiogram

This thesis studies the applicability of the electrocardiogram signal (ECG) as a biometric. There is strong evidence that heart's electrical activity embeds highly distinctive characteristics, suitable for applications such as the recognition of human subjects. Such systems traditionally provide two modes of functionality, identification and authentication; frameworks for subject recognition are herein proposed and analyzed in both scenarios. As in most pattern recognition problems, the probability of mis-classification error decreases as more learning information becomes available. Thus, a central consideration is the design and evaluation of algorithms which exploit the added information provided by the 12 lead standard ECG recording system. Feature and decision level fusion techniques described in thesis, offer enhanced security levels. The main novelty of the proposed approach, lies in the design of an identification system robust to cardiac arrhythmias. Criteria concerning the power distribution and information theoretic complexity of electrocardiogram windows are defined to signify abnormal ECG recordings, not suitable for recognition. Experimental results indicate high recognition rates and highlight identification based on ECG signals as very promising.

Keywords: biometric
electrocardiogram
Advisor: Hatzinakos, Dimitrios
An Analysis of the Expression, Regulation and Interaction of Genes and Gene Products using Computational and Molecular Methods

Bioinformatic methods were applied to address biological questions. Two new eFP browser web tools were constructed for the intuitive visualization of data from large-scale data sets. In addition, a predicted interactome was constructed for Arabidopsis thaliana and validated using a gene coexpression analysis. The Arabidopsis Interactions Viewer was created to enable access to and visualization of predicted and confirmed interactions in the Arabidopsis interactome. In a separate analysis short sequence matches were identified between introns and coding sequences in several model systems including Arabidopsis, human, C. elegans and 12 Drosophila species. Several hundred to thousands of matches were found near each other in terms of chromosomal location, and were termed Proximal Intron N-mer (PIN) matches. Sequence matches were conserved between 11 Drosophila species and D. melanogaster, suggesting a potential functional role. Novel plasmids were designed to test whether PIN matches are functional in vivo.

Keywords: Bioinformatics
Advisor: Provart, Nicholas
Expansion, Random Graphs and the Automatizability of Resolution

We explore the relationships between the computational problem of recognizing expander graphs, and the problem of efficiently approximating proof length in the well-known system of resolution. This program builds upon known connections between graph expansion and resolution lower bounds. A proof system P is (quasi-)automatizable if there is a search algorithm which finds a P-proof of a given formula f in time (quasi)polynomial in the length of a shortest P-proof of f. It is open whether resolution is (quasi-)automatizable. We prove several conditional non-automatizability results for resolution modulo new conjectures concerning the complexity of identifying bipartite expander graphs. Our reductions use a natural family of formulas and exploit the well-known relationships between expansion and length of resolution proofs. Our hardness assumptions are unsupported; we survey known results as progress towards establishing their plausibility. The major contribution is a conditional hardness result for the quasi-automatizability of resolution.

Keywords: propositional proof complexity
expander graphs
resolution
res(k)
automatizability
Advisor: Pitassi, Toniann
A Bilevel Optimization Algorithm to Identify Enzymatic Capacity Constraints in Metabolic Networks - Development and Application

Constraint-based models of metabolism seldom incorporate capacity constraints on intracellular fluxes due to the lack of experimental data. This can sometimes lead to inaccurate growth phenotype predictions. Meanwhile, other forms of data such as fitness profiling data from growth competition experiments have been demonstrated to contain valuable information for elucidating key aspects of the underlying metabolic network. Hence, the optimal capacity constraint identification (OCCI) algorithm is developed to reconcile constraint-based models of metabolism with fitness profiling data by identifying a set of flux capacity constraints that optimally fits a wide array of strains. OCCI is able to identify capacity constraints with considerable accuracy by matching 1,155 in silico-generated growth rates using a simplified model of Escherichia coli central carbon metabolism. Capacity constraints identified using experimental fitness profiles with OCCI generated novel hypotheses, while integrating thermodynamics-based metabolic flux analysis allowed prediction of metabolite concentrations.

Keywords: constraint-based modeling
metabolic engineering
flux balance analysis
redox
Advisor: Cluett, William R.
Mahadevan, Radhakrishnan
The Effects of Mechanical Loading on the Local Myofibrogenic Differentiation of Aortic Valve Interstitial Cells

Calcific aortic valve sclerosis is characterized by focal lesions in the valve leaflet. These lesions are rich in myofibroblasts that express α-SMA and cause fibrosis. Lesions tend to occur in regions of the leaflet that are subjected to large bending loads, suggesting a mechanobiological basis for myofibrogenic differentiation and valve pathogenesis. In this thesis, a bioreactor was developed to study the effect of physiological loading on myofibrogenic differentiation of valve interstitial cells. Cyclic loading of native porcine aortic valve leaflets ex vivo resulted in increased α-SMA expression, predominantly in the fibrosa and spongiosa (similar to sclerotic leaflets). Cofilin, an actin-binding protein, was also upregulated by loading, suggesting it plays a role in mechanically-induced myofibrogenesis. Similarly, loading of a tissue engineered aortic valve leaflet model resulted in increased α-SMA transcript and protein expression. These data support an integral role for mechanical stimuli in myofibrogenic differentiation and sclerosis in the aortic valve.

Keywords: Mechanobiology
Tissue Engineering
Myofibroblasts
α-Smooth Muscle Actin
Cofilin
Aortic Valve Disease
Advisor: Simmons, Craig Alexander
Longitudinal Effects of Habit-breaking Appliances on Tongue and Dento-alveolar Relations and Speech in Children with Oral Habits

A longitudinal pilot study to compare, in children with reduced overbite malocclusions associated with oral habits (finger-sucking and tongue-thrusting), the effects of the experimental Myofunctional Trainer (MFT; Myofunctional Research Co.) and the conventional Bluegrass appliance (BG) on dento-alveolar relations, tongue position, and on speech. Methods: The experimental group received the MFT appliance while the control group received the BG appliance. Dento-alveolar changes were assessed by cephalometry and study models. Longitudinal midsagittal 2-dimensional B-mode ultrasound scans of the tongue surface were performed to determine tongue position. Speech acceptability tests were also performed. Results & Conclusions: The BG appliance was successful in breaking the finger-sucking habit. The MFT appliance showed only partial success which could be attributed to lack of compliance. At the end of treatment, the open bite was reduced in both groups due to dento-alveolar changes. The BG appliance had a deleterious effect on speech acceptability while in place, while there was no such effect with the MFT appliance.

Keywords: Dentistry
Speech
Tongue Ultrasound
Oral Habits
B Mode Ultrasound
Advisor: Kulkarni, Gajanan
Bressmann, Tim
High-performance Dual-energy Imaging with a Flat-panel Detector

Mounting evidence suggests that the superposition of anatomical clutter in x-ray chest radiography poses a major impediment to the detectability of subtle lung nodules. Through decomposition of projections acquired using different x-ray energy spectra, dual-energy (DE) imaging offers to dramatically improve lung nodule conspicuity. The development of a high-performance DE chest imaging system is reported, with design and implementation guided by fundamental imaging performance metrics. Analytical and experimental studies of imaging performance guided the optimization of key acquisition technique parameters, including x-ray filtration, allocation of dose between low- and high-energy projections, and peak-kilovoltage selection. To minimize anatomical misregistration between images, a cardiac gating system was designed and implemented to direct x-ray exposures to within the quiescent period of the heart cycle. The instrumentation and optimal imaging techniques have been incorporated in a DE imaging prototype system now deployed in a clinical study to evaluate the diagnostic performance of DE imaging.

Keywords: Dual-Energy Imaging
Technique Optimization
Chest Imaging
Lung Cancer
Advisor: Siewerdsen, Jeffrey H.