title: Development of Sensitivity Analysis and Optimization for Microwave Circuits and Antennas in the Frequency Domain

contributor:
Nikolova, Natalia
Bandler, J.W.
Electrical and Computer Engineering

subject: sensitivity analysis, optimization, microwave circuits, antennas, frequency domains, adjoint variable methods, space mapping

abstract:
 This thesis contributes to the development of adjoint variable methods (AVM) and space mapping (SM) technology for computer-aided electromagnetics (EM)-based modeling and design of microwave circuits and antennas.

 The AVM is known as an efficient approach to design sensitivity analysis for problems of high complexity. We propose a general self-adjoint approach to the sensitivity analysis of network parameters for an Method of Moments (MoM) solver. It requires neither an adjoint problem nor analytical system matrix
derivatives. For the first time, we suggest practical and fast sensitivity solutions realized entirely outside the EM solver, which simplifies the implementation. We discuss: (1) features of commercial EM solvers which allow the user to compute network parameters and their sensitivities through a single full-wave simulation; (2) the accuracy of the computed derivatives; (3) the overhead of the sensitivity computation. Our approach is demonstrated by FEKO, which employs an MoM solver.

 One motivation for sensitivity analysis is gradient-based optimization. The sensitivity evaluation providing the Jacobian is a bottleneck of optimization with full-wave simulators. We propose an approach, which employs the self-adjoint sensitivity analysis of network parameters and Broyden's update for practical EM
design optimization. The Broyden's update is carried out at the system matrix level, so that the computational overhead of the Jacobian is negligible while the accuracy is acceptable for optimization. To improve the robustness of the Broyden update in the sensitivity analysis, we propose a switching criterion between the Broyden and the finite-difference estimation of the system matrix derivatives.

 In the second part, we apply for the first time a space mapping technique to antenna design. We exploit a coarse mesh MoM solver as the coarse model and align it with the fine mesh MoM solution through space mapping. Two SM plans
are employed: I. implicit SM and output SM, and II. input SM and output SM. A novel local meshing method is proposed to avoid inconsistencies in the coarse model. The proposed techniques are implemented through the new user-friendly SMF system. In a double annular ring antenna example, the S-parameter is optimized. The finite ground size effect for the MoM is efficiently solved by SM Plan I and the design specification is satisfied after only three iterations. In a patch antenna example, we optimize the impedance through both plans. Comparisons are made. Coarseness in the coarse model and its effect on the SM performance is also discussed.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Anomalous Structural Variations in III-Nitride Nanowire Heterostructures and Their Corresponding Optical Properties

contributor:
Botton, Gianluigi A.
Materials Science and Engineering

subject: semiconductor nanowires

subject: III-nitride

subject: heterostructures

subject: alloy inhomogeneity

subject: characterization

subject: nanotechnology

abstract:
Ternary InGaN and AlGaN alloys have been sought after for the application of various optoelectronic devices spanning a large spectral range between the deep ultraviolet and infrared, including light-emitting diodes, and laser diodes. Their non-ideal alloy mixing, and differences in bond energy and in adatom diffusion are established as the cause for various types of nanoscale compositional inhomogeneity commonly observed in nitride thin films. Growth in a nanowire geometry can overcome the phase separation, surface segregation, and chemical ordering by providing enhanced strain relaxation of the large lattice mismatch at the free surfaces. In this dissertation, the spectral and spatial luminescence distributions of ternary III-N alloy nanowire heterostructures are investigated and correlated to structural and chemical properties with scanning transmission electron microscopy.
Quantitative elemental mapping of InGaN/GaN dot-in-a-wire structures using electron energy-loss spectroscopy revealed compositional non-uniformity between successive quantum dots. Local strain mapping of the heterostructure showed a dependence of the incorporation of indium on the magnitude of the out-of-plane compressive strain within the underlying GaN barrier layer. Cathodoluminescence spectroscopy on individual nanowires presented diverse emission properties, nevertheless, the In-content variability could be directly correlated to the broad range of peak emission energies.
Atomic-level chemical ordering within the InGaN was then reported, and attributed to the faceted growth surface in nanowires that promotes preferential site incorporation by In-atoms that allows for better strain relaxation. Distinct atomic-scale alloy inhomogeneities were also investigated in AlGaN nanowires, which evidenced spatial localization of carriers taking place at the resulting energy band fluctuations. A high spectral density of narrow emission lines arose from such compositional modulations, whose luminescence behaviours exhibit a dependence on the nature of the compositional fluctuations from which they originate.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Investigating traditional and emerging cardiovascular disease risk factors in paediatric populations with chronic inflammatory disease

contributor:
MacDonald, Maureen
Kinesiology

subject:
Inflammation
Cardiovascular disease
Juvenile idiopathic arthritis
Cystic fibrosis
Type I diabetes mellitus
Inflammatory bowel disease
Intima media thickness
Arterial stiffness
Endothelial function

abstract:
For most children, occult vascular damage is minimal and has a slow rate of progression likely due to the existence of healthy lifestyles and the prevalence of preventative behaviours. However, there is evidence to suggest a marked increase in the prevalence of traditional and emerging cardiovascular risk factors in children with chronic inflammatory conditions due to the common aetiology pathways of inflammation and atherosclerosis. In the current cross-sectional study, a comprehensive vascular assessment was conducted on 21 children with various chronic inflammatory conditions including juvenile idiopathic arthritis (JIA), cystic fibrosis (CF), type I diabetes mellitus (T1DM) and inflammatory bowel disease (IBD) (CIC, 12.7 ± 2.3 years) compared to 9 healthy, age and sex- matched controls (CON, 13.1 ± 1.8 years). B-mode ultrasound images were used to assess carotid artery intima media thickness (cIMT) as well as local arterial stiffness through measurement of compliance and distensibility with the use of concurrent applanation tonometry. Whole-body arterial stiffness was measured by assessing pulse wave velocity (PWV) between the carotid and dorsalis pedis arteries. A brachial flow mediated dilation (FMD) test was implemented to assess endothelial function of the brachial artery. Twelve hour-fasted blood samples were collected and analyzed for blood lipids and an acute inflammatory marker, C-reactive protein (CRP). There were no group differences in cIMT (p=0.18), distensibility (p=0.40), compliance (p=0.88), whole body PWV (p=0.74) or LDL- cholesterol (p=0.99). The CIC group demonstrated significantly lower FMD when
iii
compared to CON (p=0.01). There were no group differences in inflammatory levels, as indicated by concentration of CRP (p=0.63). Sub-analyses revealed similar cIMT, distensibility, compliance, PWV and LDL levels between children with JIA (n=11, 12.6 ± 2.9 years), CON (n=9, 13.1 ± 1.8 years) and the other inflammatory conditions (INFL, n=10, 12.4 ± 1.7 years). Both JIA and INFL reported lower FMD when compared to CON (p=0.04). INFL had lower BMI compared to JIA and CON (p=0.02). The primary findings from this study suggest that arterial structure is similar between children with a CIC and their healthy peers; however, arterial function, as indicated by FMD (%), was reduced in the CIC group. This finding is essential in that it helps to identify an area for targeted intervention and/or prevention of future CV events as endothelial dysfunction is known to be an early event in the pathophysiology of atherosclerosis.

abstract: Thesis

abstract: Master of Science (MSc)


title: Analysis and Comparison of System Performance Using Different Modulation Schemes for Long-Haul Optical Systems and Fiber-To-The-Home Passive Optical Networks

contributor:
Kumar, Shiva
Li, Xun
Electrical and Computer Engineering

subject: system performance, modulation schemes, long-haul, optical systems, fiber, passive, networks, transmission

abstract:
 Analytical expressions for the propagation impairments due to various noise sources in long-haul optical systems and fiber-to-the-home passive optical networks have been obtained. Extensive comparison has been made in this thesis for systems based on different modulation formats, and the advantage of one over the other is clearly stated.

 For long-haul fiber optical communication systems with inline amplifiers, we have studied the statistical properties of various noise sources in systems based on differential phase-shift keying (DPSK) such as the linear phase noise induced by the amplifier spontaneous emission (ASE) noise, the intra-channel four-wave mixing (IFWM) and the nonlinear phase noise induced by the interplay between ASE noise and fiber Kerr nonlinearity. The error probability of the system based on DPSK is evaluated semi-analytically. In addition, the error probability of the system based on on-off keying (OOK) is calculated taking into account the effects of ASE noise, and the intra-channel nonlinearities such as IFWM and intra-channel cross-phase modulation (IXPM). Comparison of the performance of systems based on DPSK and OOK is made thereafter.

 For fiber-to-the-home passive optical networks without inline active
photonic devices, different modulation formats have been examined for the downstream and upstream data to enable full-duplex transmission. The statistical properties of Rayleigh backscattering in single-source bi-directional optical systems have been studied including the effects of the high speed external modulation signal and the laser phase noise for systems based on DPSK and OOK. The error probabilities for systems using OOK/OOK topology and DPSK/OOK topology for downstream/upstream transmission have been evaluated and
compared.

 In addition, the interplay of the amplifier spontaneous emission noise,
fiber nonlinearity and dispersion has been examined starting from the nonlinear Schrödinger equation on the receiver current fluctuation. The variance of the current noise has been evaluated analytically using the two dimensional perturbation theory.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: CURE RATE AND DESTRUCTIVE CURE RATE MODELS UNDER PROPORTIONAL HAZARDS LIFETIME DISTRIBUTIONS

contributor:
Balakrishnan, Narayanaswamy
Mathematics and Statistics

subject:
Cure Rate Model
Proportional Hazards
COM Poisson

abstract:
Cure rate models are widely used to model time-to-event data in the presence of long-term survivors. Cure rate models, since introduced by Boag (1949), have gained significance  over time due to remarkable advancements in the drug industry resulting in cures for a number of diseases. In this thesis, cure rate models are considered under a competing risk scenario wherein the initial number of competing causes is described by a Conway-Maxwell (COM) Poisson distribution,  under the assumption of proportional hazards (PH) lifetime for the susceptibles. This provides a natural extension of the work of Balakrishnan & Pal (2013) who had considered independently and identically distributed (i.i.d.) lifetimes in this setup. By linking covariates to the lifetime through PH assumption, we obtain a flexible cure rate model. First, the  baseline hazard is assumed to be of the Weibull form. Parameter estimation is carried out using  EM algorithm and the standard errors are estimated using Louis'  method. The performance of estimation is assessed through a simulation study. A model discrimination study is performed using Likelihood-based and Information-based criteria since the COM-Poisson model includes geometric, Poisson and Bernoulli as special cases. The details are covered in Chapter 2.
As a natural extension of this work, we next approximate the baseline hazard with a piecewise linear functions (PLA) and estimated it non-parametrically for the COM-Poisson cure rate model under PH setup. The corresponding simulation study and model discrimination results are presented in Chapter 3. Lastly, we consider a destructive cure rate model, introduced by Rodrigues et. al (2011), and study it under the PH assumption for the lifetimes of susceptibles. In this, the initial number of competing causes are modeled  by a weighted Poisson distribution. We then focus mainly on three special cases, viz., destructive exponentially weighted Poisson, destructive length-biased Poisson and destructive negative binomial cure rate models, and all corresponding results are  presented in Chapter 4.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: PRMT Biology During Acute Exercise

contributor:
Ljubicic, Vladimir
Kinesiology

subject:
Protein arginine methyltransferase
Exercise
Skeletal muscle
Fiber types
PGC-1alpha

abstract: Protein arginine methyltransferase 1 (PRMT1), -4 (also known as coactivator-associated arginine methyltransferase 1; CARM1), and -5 catalyze the methylation of arginine residues on target proteins. In turn, these marked proteins mediate a variety of biological functions. By regulating molecules that are critical to the remodelling of skeletal muscle phenotype, PRMTs may influence skeletal muscle plasticity. Our study tests the hypothesis that the intracellular signals required for muscle adaptation to exercise will be associated with the induction of PRMT expression and activity. C57BL/6 mice were assigned to one of three experimental groups: sedentary (SED), acute bout of exercise (0PE), or acute exercise followed by 3 hours of recovery (3PE). The mice in the exercise groups performed a single bout of treadmill running at 15 m/min for 90 minutes. We observed that PRMT gene expression and global enzyme activity are muscle- specific, generally being higher in slow, oxidative muscle, as compared to faster, more glycolytic tissue. Despite the activation of canonical exercise-induced signalling involving AMPK and PGC-1α, PRMT expression and activity at the whole muscle level were unchanged. However, subcellular analysis revealed the exercise-evoked myonuclear translocation of PRMT1 prior to the nuclear translocation of PGC-1α, which colocalizes the proteins within the organelle after exercise. Acute physical activity also augmented the targeted methyltransferase activities of CARM1, PRMT1, and -5 in the myonuclear compartment, suggesting that PRMT-mediated histone arginine methylation is an integral part of the early signals that drive skeletal muscle plasticity. In summary, our data supports the emergence of PRMTs as important players in the regulation of skeletal muscle plasticity.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: Skeletal muscle is a plastic tissue that can adapt to various physiological demands. Previous work suggests that protein arginine methyltransferases (PRMTs) are important in the regulation of skeletal muscle remodeling. However, their role in exercise-induced skeletal muscle plasticity is unknown. Therefore, the purpose of this study was to investigate the association between the intracellular signals required for muscle adaption and various metrics of PRMT biology. Our data demonstrate that PRMTs exhibit muscle-specific expression and function in mice. The movement of PRMT1 into myonuclei increased following exercise, while the specific methylation status of PRMT targets were also elevated. Overall, our data suggests that muscle-specific PRMT expression may be important for the determination and/or maintenance of different fiber type characteristics. Moreover, distinct PRMT cellular localization and methyltransferase activity may be key signals that contribute to skeletal muscle phenotypic plasticity.


title: THE ROLE OF AMPK IN THE EXPRESSION OF THE DAPC

title: THE ROLE OF AMPK IN THE EXPRESSION OF THE DYSTROPHIN-ASSOCIATED PROTEIN COMPLEX IN SKELETAL MUSCLE

subject: AMP-activated protein kinase, dystrophin-associated protein complex, skeletal muscle, utrophin, peroxisome proliferator-activated receptor γ coactivator-1α

abstract: The dystrophin-associated protein complex (DAPC) provides a mechanical link between the intracellular cytoskeleton and extracellular matrix, serving as a mechanosensor and signal transducer across the sarcolemma. Pharmacological stimulation of AMP-activated protein kinase (AMPK) induces the expression of DAPC components in skeletal muscle, whereas physiological reductions in AMPK are associated with DAPC dysfunction. We sought to determine whether AMPK was necessary for the maintenance of DAPC expression in skeletal muscle. Fast glycolytic extensor digitorum longus (EDL) and slow oxidative soleus (SOL) muscles from wild-type (WT) mice, as well as from littermates deficient in both isoforms of the AMPK-β subunit in skeletal muscle (MKO) were analyzed. DAPC mRNA levels, as well as protein expression and localization were similar between genotypes, with the exception of nNOS, which displayed a compensatory sarcolemmal enrichment in MKO muscles. The content of transcriptional and post-transcriptional regulators of the DAPC, such as PGC-1α and KSRP, were also not affected by the loss of AMPK. However, MyoD and myogenin expression was significantly diminished in MKO muscles, which is consistent with previous reports of myopathy in these animals. Furthermore, we observed decrements in extrasynaptic utrophin expression selectively in MKO SOL muscles, despite an adaptive accumulation of PGC-1α at the sarcolemmal compartment. Collectively the evidence indicates that AMPK is sufficient, but not essential for the maintenance of DAPC expression in skeletal muscle. However, AMPK is required for preserving extrasynaptic utrophin levels in slow, oxidative muscles, which underscores the role of AMPK in the gene expression of this disease modifying protein.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: The dystrophin-associated protein complex (DAPC) connects the interior and exterior of muscle cells. Activation of AMP-activated protein kinase (AMPK) increases the expression of the DAPC in skeletal muscle. We sought to determine whether AMPK was necessary for DAPC expression in skeletal muscle. Fast and slow muscles from normal mice, as well as from those deficient in skeletal muscle AMPK (MKO) were analyzed. We found DAPC levels and localization were similar between both groups, with the exception of nNOS, which was enriched at the muscle membrane in MKO muscles. Regulators of the DAPC were also not affected by the loss of AMPK. However, genes important for the production of muscle were significantly diminished in MKO muscles. Furthermore, we observed decrements in utrophin at the muscle membrane selectively in slow MKO muscles. Our work indicates that AMPK is not essential for the DAPC expression in skeletal muscle, however it is required for preserving utrophin levels in slow, oxidative muscles.


title: Likelihood inference for multiple step-stress models from a generalized Birnbaum-Saunders distribution under time constraint

contributor:
Balakrishnan, Narayanaswamy
Computational Engineering and Science

subject: Accelerated life testing

subject: Cumulative exposure model

subject: Multiple step-stress models

subject: Student's t Birnbaum-Saunders distribution

subject: EM algorithm

subject: Model discrimination

subject: Type-I censoring

subject: Maximum likelihood

subject: Optimal designs

subject: Bootstrapping

abstract:
Researchers conduct life testing on objects of interest in an attempt to determine their life distribution as a means of studying their reliability (or survivability). Determining the life distribution of the objects under study helps manufacturers to identify potential faults, and to improve quality. Researchers sometimes conduct accelerated life tests (ALTs) to ensure that failure among the tested units is earlier than what could result under normal operating (or environmental) conditions. Moreover, such experiments allow the experimenters to examine the effects of high levels of one or more stress factors on the lifetimes of experimental units. Examples of stress factors include, but not limited to, cycling rate, dosage, humidity, load, pressure, temperature, vibration, voltage, etc. A special class of ALT is step-stress accelerated life testing. In this type of experiments, the study sample is tested at initial stresses for a given period of time. Afterwards, the levels of the stress factors are increased in agreement with prefixed points of time called stress-change times. In practice, time and resources are limited; thus, any experiment is expected to be constrained to a deadline which is called a termination time. Hence, the observed information may be subjected to Type-I censoring.

This study discusses maximum likelihood inferential methods for the parameters of multiple step-stress models from a generalized Birnbaum-Saunders distribution under time constraint alongside other inference-related problems. A couple of general inference frameworks are studied; namely, the observed likelihood (OL) framework, and the expectation-maximization (EM) framework. The last-mentioned framework is considered since there is a possibility that Type-I censored data are obtained. In the first framework, the scoring algorithm is used to get the maximum likelihood estimators (MLEs) for the model parameters. In the second framework, EM-based algorithms are utilized to determine the required MLEs. Obtaining observed information matrices under both frameworks is also discussed. Accordingly, asymptotic and bootstrap-based interval estimators for the model parameters are derived. Model discrimination within the considered generalized Birnbaum-Saunders distribution is carried out by likelihood ratio test as well as by information-based criteria. The discussed step-stress models are illustrated by analyzing three real-life datasets. Accordingly, establishing optimal multiple step-stress test plans based on cost considerations and three optimality criteria is discussed. Since maximum likelihood estimators are obtained by numerical optimization that involves maximizing some objective functions, optimization methods used, and their software implementations in R are discussed. Because of the computational aspects are in focus in this study, the benefits of parallel computing in R, as a high-performance computational approach, are briefly addressed. Numerical examples and Monte Carlo simulations are used to illustrate and to evaluate the methods presented in this thesis.

abstract: Thesis

abstract: Doctor of Science  (PhD)


title: An Optimization-Based Parallel Particle Filter for Multitarget Tracking

contributor:
Kirubarajan, T.
Electrical and Computer Engineering

subject: optimization-based, parallel particle filter, multitarget tracking, algorithm

abstract: Particle filters are being used in a number of state estimation applications because of their capability to effectively solve nonlinear and non-Gaussian problems. However, they have high computational requirements and this becomes even more so in the case of multitarget tracking, where data association is the bottleneck. In order to perform data association and estimation jointly, typically an augmented state vector, whose dimensions depend on the number of targets, is used in particle filters. As the number of targets increases, the corresponding computational load increases exponentially. In this case, parallelization is a possibility for achieving real-time feasibility in large-scale multitarget tracking applications. In this paper, we present an optimization-based scheduling algorithm that minimizes the total computation time for the bus-connected heterogeneous primary-secondary architecture. This scheduler is capable of selecting the optimal number of processors from a large pool of secondary processors and mapping the particles among the selected ones. A new distributed resampling algorithm suitable for parallel computing is also proposed. Furthermore, a less communication intensive parallel implementation of the particle filter without sacrificing tracking accuracy using an efficient load balancing technique, in which optimal particle migration among secondary processors is ensured, is presented. Simulation results demonstrate the tracking effectiveness of the new parallel particle filter and the speedup achieved using parallelization.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: CHARACTERIZING LARGE CONDUCTANCE POTASSIUM CHANNELS IN THE INTRINSIC PRIMARY AFFERENT NEURONS OF MOUSE JEJUNUM

contributor: Medical Sciences (Division of Physiology/Pharmacology)

subject:
slow afterhyperpolarisation
potassium channels
electrophysiology
intrinsic primary afferent neurons

abstract: The large conductance calcium dependent potassium (BKCa) channels are expressed in a large variety of cell types including neurons where they modulate excitability and action potential shape. Within the enteric nervous system, stretch-sensitive BKCa channels are expressed on intrinsic primary afferent neurons (IPANs) where they decrease the neurons’ excitability during intestinal contractions. A major determinant of peristalsis is slow excitatory neurotransmission (sEPSPs) within the IPAN to IPAN sensory network, and we wondered whether such transmission might also alter BKCa channel opening. All experiments were performed on longitudinal-muscle myenteric preparations prepared from jejunal segment taken from freshly euthanized adult male Swiss Webster mice. With the myenteric plexus exposed by microdissection, BKCa channel activity was recorded in cell-attached mode via the patch clamp technique. BKCa channel activity was recorded before and after presynaptic electrical stimulation, which was designed to evoke postsynaptic sEPSPs. The morphotype was verified by intracellular injection of a marker dye (neurobiotin). In addition, a blocker and opener were used to identify the effects of BKCa currents on IPAN properties. Analysis of unitary channel recordings revealed increased BKCa open probability (NPo) at fixed trans-patch potentials following sEPSPs. All BKCa channels were independently voltage sensitive with increased NPo during patch depolarisation. Analysis of whole-cell experiments also revealed BKCa channels have a significant effect on the undershoot amplitude of action potentials, and the rate at which IPANs repolarise. This study demonstrates that sEPSPs within the enteric nervous system modulate the function of BKCa channels in IPANs adding to the mechanistic understanding of enteric synaptic transmission and providing a potential target for therapeutic modulation of enteric nervous system excitability.

abstract: Thesis

abstract: Master of Science (MSc)


title: Robust Sequential View Planning for Object Recognition Using Multiple Cameras

contributor:
Sirouspour, Shahin
Kirubarajan, Thiagalingam
Electrical and Computer Engineering

subject: robust, sequential, view planning, object recognition, multiple cameras

abstract:
 In this thesis the problem of object recognition/pose estimation using active sensing is investigated. It is assumed that multiple cameras acquire images from different view angles of an object belonging to a set of a priori known objects. The eigenspace method is used to process the sensory observations and produce an abstract measurement vector. This step is necessary to avoid the manipulation of the original sensor data, i.e. large images, that can render the sensor modelling and matching process practically infeasible.

 The eigenspace representation is known to have shortcomings in dealing with structured noise such as occlusion. To overcome this problem, models of occlusions and sensor noise have been incorporated into the probabilistic model of sensor/object to increase robustness with respect to such uncertainties. The active recognition algorithm has also been modified to consider the possibility of occlusion, as well as variation in the occlusion levels due to camera movements.

 A recursive Bayesian state estimation problem is formulated to model the observation uncertainties through a probabilistic scheme. This enables us to identify the
object and estimate its pose by fusing the information obtained from individual cameras. To this end, an extensive training step is performed, providing the system with the sensor model required for the Bayesian estimation. In order to enhance the quality of the estimates and to reduce the number of images taken, we employ active real-time viewpoint planning strategies to position cameras. For that purpose, the positions of cameras are controlled based on two different statistical performance criteria, namely the Mutual Information (MI) and Cramér-Rao Lower Bound (CRLB).

 A multi-camera active vision system has been developed in order to implement the ideas proposed in this thesis. Comparative Monte Carlo experiments conducted with the two-camera system demonstrate the effectiveness of the proposed methods in object classification/pose estimation in the presence of structured noise. Different
concepts introduced in this work, i.e., the multi-camera data fusion, the occlusion modelling, and the active camera movement, all improve the recognition process significantly. Specifically, these approaches all increase the recognition rate, decrease the number of steps taken before recognition is completed, and enhance robustness with respect to partial occlusion considerably.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Finite Element Analysis of Unreinforced Concrete Block Walls Subject to Out-of-Plane Loading

contributor:
Chidiac, Samir
Drysdale, Robert
Civil Engineering

subject: Concrete block walls, Out-of-plane loading, finite element software packages, Newton-Raphson method

abstract:
Finite element modeling of the structural response of hollow concrete block walls subject to out-of-plane loading has become more common given the availability of computers and general-purpose finite element software packages. In order to develop appropriate models of full-scale walls with and without openings, a parametric study was conducted on simple wall elements to assess different modeling techniques. Two approaches were employed in the study, homogeneous models and heterogeneous models. The linear elastic analysis was carried out to quantify the effects of the modeling techniques for hollow blocks on the structural response of the assembly, specifically for out-of-plane bending. Three structural elements with varying span/thickness ratios were considered, a horizontal spanning strip, a vertical spanning strip and a rectangular wall panel supported on four edges. The values computed using homogeneous and heterogeneous finite element models were found to differ significantly depending on the configuration and span/thickness ratio of the wall.

Further study was carried out through discrete modeling approach to generate a three-dimensional heterogeneous model to investigate nonlinear behaviour of full-scale walls under out-of-plane loading. The Composite Interface Model, established based on multi-surface plasticity, which is capable of describing both tension and shear failure mechanisms, has been incorporated into the analysis to capture adequately the inelastic behaviour of unit-mortar interface.An effective solution procedure was achieved by implementing the Newton-Raphson method, constrained with the arc-length control method and enhanced by line search algorithm. The proposed model was evaluated using experimental results for ten full-size walls reported in the literature. The comparative analysis has indicated very good agreement between the numerical and experimental results in predicting the cracking and ultimate load values as well as the corresponding crack pattern.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Communication of 3D Graphic Models

contributor:
Shirani, Shahram
Capson, David W.
Electrical and Computer Engineering

subject: communication, 3D graphic models, polygon, algorithm

abstract:
 A new area-based mesh simplification algorithm is described. The proposed algorithm
removes the center vertex of a polygon which consists of n ≥ 3 faces and represents that polygon with n - 2 faces. A global search method is adapted that iteratively determines which vertex is to be removed using the proposed area-based distortion measurement. Although the global search method requires more computations compared to a local search method, it guarantees better quality of approximation. Various re-triangulations are also considered to improve the perceptual quality of the final approximation.

 From multiple re-triangulations, one with minimum distortion is selected to represent the original mesh. Experimental results demonstrate the performance of the proposed algorithm for data reduction while maintaining the quality of the rendered objects. The performance of multiple description decoder when not all descriptions are available depends on the decoding strategy. By approximating lost description the distortion can be reduced. When decoder reconstructs input source without having all descriptions different methods exist to approximate the
lost description. We proposed two side decoding algorithms. The proposed side decoders are based on diagonal element and the probability of input source. When low bit-rate and complicated index assignment matrix are used the side decoder based on probability of input source is recommendable. To approximate the lost description we compare the performance of standard decoding method with the performance of proposed methods. A trade-off between the performance of decoder and computational complexity exists.

 An error concealment algorithm is proposed based on flow of facial expression to improve communication of animated facial data over a limited bandwidth channel with error. Facial expression flow is tracked using dominant muscles which are those with maximum change between two successive frames. By comparing the dominant muscle data with the predetermined expression information table, facial expression flow is determined. The receiver uses linear interpolation and the information on facial expression flow to interpolate the erroneous facial animation data. For objective comparison, a distortion measurement tool, which compares two 3D objects based on point-to-point difference, is introduced. Experimental results are provided to show that the proposed error concealment method improves the quality of an animated face communications.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: MULTIVARIATE DATA ANALYSIS FOR FORCE-, DISPLACEMENT-, AND PERFORMANCE-BASED SEISMIC DESIGN OF REINFORCED MASONRY SHEAR WALLS

contributor:
El-Dakhakhni, Wael
Li, Zoe
Civil Engineering

abstract:
Over the past decades, seismic analysis and design have been thoroughly addressed
by the majority of international building codes and standards. Although seismic
damage of structural components typically correlate better to displacement, rather
than forces, current seismic codes adopt force-based seismic design (FBSD)
approaches. However, in the past two decades, there has been a gradual shift from
“strength” to “performance” through the introduction of performance-based
seismic deign (PBSD) of structural components that can be implemented with
relative ease through displacement-based seismic design (DBSD) approaches. For
reinforcement masonry shear wall (RMSW), several gaps still exist in
implementing FBSD, DBSD and PBSD. Some of these gaps include: quantifying
the reliability of the ductility-related parameters when a FBSD approach is adopted;
quantifying a reliable maximum lateral load displacement when a DBSD approach
is implemented; developing a backbone curve model so that different damage states
can be identified when implementing PBSD approach. As such, this dissertation
attempts to tackle these issues within the different seismic design approaches.
For FBSD, this study assesses the reliability of eight published plastic hinge models
using a large database of experimentally tested RMSW. In addition to assessing
model reliability in terms of displacement predictability, this dissertation also
specifies calibration factors to further improve the evaluated models. For DBSD,
multivariate data analysis technique through the principal component analysis
(PCA) technique and partial least square (PLS) analysis technique is utilized to
develop an experimentally calibrated RMSW displacement prediction expressions
for both the maximum lateral load limit state and the ultimate displacement limit
state. These expressions are further utilized to evaluate the parameters influencing
RMSW displacement capacities. For PBSD, complete backbone curve model for
RMSW under lateral loads is developed in this dissertation and subsequently
utilized to generate an analytical RMSW performance database. This large database
is further utilized to generate seismic fragility bands that are compared to the FEMA
P-58 fragility curves in an effort to represent a more realistic means of quantifying
RMSW performance and damage states under different seismic demand levels.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Joint Detection and Tracking of Unresolved Targets with a Monopulse Radar Using a Particle Filter

subject: joint detection, unresolved targets, monopulse radar, particle, filter, nonlinear

abstract: Detection and estimation of multiple unresolved targets with a monopulse radar is a challenging problem. For ideal single bin processing, it was shown in the literature that at most two unresolved targets can be extracted from the complex matched filter output signal. In this thesis, a new algorithm is developed to jointly detect and track more than two targets from a single detection. This method involves the use of tracking data in the detection process. For this purpose, target states are transformed into the detection parameter space, which involves high nonlinearity. In order to handle this, the sequential Monte Carlo (SMC) method, which has proven to be effective in nonlinear non-Gaussian estimation problems, is used as the basis of the closed loop system for tracking multiple unresolved targets. In addition to the standard SMC steps, the detection parameters corresponding to the predicted particles are evaluated using the nonlinear monopulse radar beam model. This in turn enables the evaluation of the likelihood of the monopulse signal given tracking data. Hypothesis testing is then used to find the correct detection event. The particles are updated and resampled according to the hypothesis that has the highest likelihood (score). A simulated amplitude comparison monopulse radar is used to generate the data and to validate the extraction and tracking of more than two unresolved targets.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Adaptive Fractionally-Spaced Equalization with Explicit Sidelobe Control Using Interior Point Optimization Techniques

contributor:
Davidson, T. N.
Electrical and Computer Engineering

subject: fractionally-spaced, equalization, explicit sidelobe control, interior point, optimization techniques, digital communication

abstract:
 This thesis addresses the design of fractionally-spaced equalizers for a digital communication system which is susceptible to Adjacent Channel Interference (ACI). ACI can render an otherwise well designed system prone to excess bit errors. Algorithms for a trained adaptive FIR linear fractionally-spaced equalizer (FSE) with explicit sidelobe control are developed in order to provide robustness to ACI. The explicit sidelobe control is achieved by imposing a quadratic inequality constraint on the frequency response of the equalizer at a discrete set of frequency points in the sidelobe region.

 Algorithms are developed for both block adaptive and symbol-by-symbol adaptive modes. These algorithms use interior point optimization techniques to find the optimal equalizer coefficients. In the block adaptive mode, the problem is reformulated as a Second Order Cone Program (SOCP). In the symbol-by-symbol adaptive mode, the philosophy of the barrier approach to interior point methods is adopted. The concept of a central path and the Method of Analytic Centers (MAC) are used to develop two practically implementable algorithms, namely IPM2 and SBM, for performing symbol-by-symbol adaptive, fractionally-spaced equalization, with multiple quadratic inequality constraints.

 The performance of the proposed algorithms is compared to that of the Wiener filter, and the standard RLS algorithm with explicit diagonal loading. In the computer simulations, the proposed algorithms perform better in the sense that they provide the desired robustness when the communication model is prone to intermittent interferers in the sidelobe region of the frequency response of the FSE. Although the proposed algorithms have a moderately higher computational cost, their insensitivity to the deleterious effects of ACI make them an attractive choice in certain applications.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Multivariate Analysis Applied to Discrete Part Manufacturing

contributor:
Veldhuis, S. C.
Mechanical Engineering

subject: Discrete Part Manufacturing, Multivariate analysis techniques, Principal component analysis, Partial least squares

abstract:
The overall focus of this thesis is the implementation of a process monitoring
system in a real manufacturing environment that utilizes multivariate analysis techniques
to assess the state of the process. The process in question was the medium-high volume
manufacturing of discrete aluminum parts using relatively simple machining processes
involving the use of two tools. This work can be broken down into three main sections.

The first section involved the modeling of temperatures and thermal expansion
measurements for real-time thermal error compensation. Thermal expansion of the Z-axis
was measured indirectly through measurement of the two quality parameters related
to this axis with a custom gage that was designed for this part. A compensation strategy
is proposed which is able to hold the variation of the parts to ±0.02mm, where the
tolerance is ±0.05mm.

The second section involved the modeling of the process data from the parts that
included vibration, current, and temperature signals from the machine. The modeling of
the process data using Principal Component Analysis (PCA), while unsuccessful in
detecting minor simulated process faults, was successful in detecting a miss-loaded part
during regular production. Simple control charts using Hotelling's T^2 statistic and
Squared Prediction Error are illustrated. The modeling of quality data from the process
data of good parts using Projection to Latent Structures by Partial Least Squares (PLS)
data did not provide very accurate fits to the data; however, all of the predictions are
within the tolerance specifications.

The final section discusses the implementation of a process monitoring system
in both manual and automatic production environments. A method for the integration
and storage of process data with Mitutoyo software MCOSMOS and MeasurLink® is
described. All of the codes to perform multivariate analysis and process monitoring were
written using Matlab.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Stabilizing Power Oscillation with the New Phase Modulation Method for Synthetic Loading of Induction Motors

contributor:
Szabados, Barna
Electrical and Computer Engineering

subject: stabilizing power oscillation, new phase, modulation method, synthetic loading, induction motors

abstract:
 Conventional method for testing the total power loss and internal temperature rise of induction motors under full load can often be a complex and costly process. The new phase modulation method for synthetic full-load testing of induction machines has been proven viable, provided the power oscillation in this method can be minimized. This thesis explores two techniques for stabilizing power fluctuation in the new method, and determines the test system's power sensitivities to parameter changes in the equivalent circuit of the induction motors under test.

 A computer simulation representing the test system used in the new phase modulation method was developed, and an experimental testing facility was built to test the technique devised for suppressing power oscillation in the test system.

 The results from simulations are analyzed and compared to those obtained from the actual experiments in order to identify the feasible power-suppressing technique, and determine the induction machine parameters responsible for causing power unbalance in the test system.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Comparative Metagenomics of Freshwater Cyanobacteria Bloom and Non-Bloom Sites in Ontario and the Investigation into the Utilization of Conserved Signature Proteins for Identification of Cyanobacteria

contributor:
Schellhorn, Herb
Biology

subject:
Cyanobacteria
Sequencing
Metagenomics
Bioinformatics
Microbiology
Microbial Ecology

abstract: Cyanobacterial algal blooms have been increasing in frequency and severity over the past few years in Ontario. Depending on the presence of toxigenic Cyanobacteria, these blooms have the potential to release toxins into the water, posing a public and environmental risk to humans and animals. Although traditional methods of studying Cyanobacteria provide important information regarding the microbial community, metagenomic sequencing allows for a more comprehensive examination of microbial diversity and functional capacities as limitations in cultivating organisms is circumvented. Therefore, to gain insight into the community composition of freshwater blooms and to compare them to non-bloom sites within Ontario, we collaborated with the Ministry of the Environment and Climate Change (MOECC) to undergo a high throughput DNA sequencing approach for a comparative metagenomic analysis. In 2015, 108 bloom and non-bloom samples were collected and sent for 16S rRNA sequencing and a subset of these were chosen for shotgun metagenomic sequencing. Our study focuses on comparing community structure and functional differences that may exist between bloom and non-bloom sites as well as analyzing differences in cyanobacterial communities across bloom sites. Our findings reveal differences in the microbial communities between these two environments. At the functional level, large-scale functionalities were conserved across the two groups but differences in specialized functions were revealed. Overall, our results show that metagenomics is a powerful tool for delineating functional and taxonomic analysis of bloom and non-bloom sites across Ontario. The second part of this work studied the utilization of the molecular marker, Conserved Signature Proteins (CSPs), as a valid method for identifying Cyanobacteria to facilitate the problem of cyanobacterial taxonomic classification. It was found that CSPs proved to be reliable in identifying Cyanobacteria within environmental samples when compared to amplicon and shotgun metagenomic sequencing approaches.

abstract: Thesis

abstract: Master of Science (MSc)


title: Profile of Canadian adults with type 2 diabetes mellitus and factors associated with diabetes-related complications

contributor:
O'Reilly, Daria
Health Research Methodology

subject:
Type 2 Diabetes
Diabetes-related complications

abstract:
Objectives: To describe the profile of Canadian adults with type 2 diabetes mellitus (T2DM), examine the prevalence of diabetes-related complications and investigate the factors associated with having common diabetes-related complications.

Methods: Self-reported data from Statistics Canada’s 2011 Survey on Living with Chronic Diseases in Canada (SLCDC) – Diabetes component were available to describe the prevalence of T2DM, related complications and co-morbidities. Associations with diabetes-related complications were evaluated using logistic regression models. Survey weights and bootstrapping resampling method were applied to account for the complex survey design.

Results: 2,341 T2DM respondents (weighted Canadian population estimate n=1,365,165) had a mean age of 62.9 years and diabetes duration of 10.6 years. The prevalence of diabetes-related complications and comorbidities were high: eye (34.0%), foot or leg (24.4%), cardiovascular (22.6%), renal (15.7%), neuropathy (10.8%), hypertension (68.4%) and high cholesterol (67.2%). Factors associated with diabetes-related complications were: Eye: > 65 years of age (odds ratio [OR] 3.7, 95% CI 2.4 – 5.5, p=<0.0001); household income < $29,999 (OR 1.9, 95% CI 1.1 – 3.2, p=0.01), diabetes duration > 10 years (OR 2.3, 95% CI 1.6 – 3.5, p<0.001), cardiovascular complications (OR 1.8, 95% CI 1.1 – 2.9, p=0.01). Renal: duration of diabetes 6 – 9 years (OR 3.0, 95% CI 1.4 – 6.3, p=0.02), duration of diabetes > 10 years (OR 2.1, 95% CI 1.1 – 3.9, p=0.04) Cardiovascular: male sex (OR 1.9, 95% CI 1.3 – 2.7, p=0.0006), eye complication (OR 1.9, 95% CI 1.2 – 3.0, p=0.007), foot or leg complication (OR 2.0, 95% CI 1.3 – 3.0, p=0.002). Foot or leg: cardiovascular complication (OR 2.0, 95% CI 1.4 – 3.1, p=0.0006). Neuropathy: household income $30,000 - $59,999 (OR 2.1, 95% CI 1.2 – 3.9, p=0.03); duration of diabetes >10 years (OR 1.9, 95% CI 1.1 – 3.8, p=0.01), foot or leg complication (OR 7.0, 95% CI 4.1 – 11.8, p<0.0001), eye complication (OR 2.0, 95% CI 1.1 – 3.7, p=0.006).

Conclusions: The presence of diabetes-related complications among Canadians with T2DM is multifactorial.

abstract: Thesis

abstract: Master of Science (MSc)


title: A Bluetooth Scatternet Formation Mechanism Based on Traffic Distribution in an Infrastructure Network

contributor:
Todd, Terence D.
Electrical and Computer Engineering

subject: bluetooth, scatternet formation mechanism, traffic distribution, infrastructure network, wireless communication, hotspot flows

abstract:
 Wireless communication has been thriving in recent years. Developments in the hardware and software industries enable more and more devices to be embedded in wireless
communication modules. All kinds of interesting applications based on wireless connections
are emerging, demanding simple and efficient ways to inter-connect different devices. Bluetooth is an industry standard initially proposed by Ericsson, IBM, Microsoft and some other leading IT companies to meet this growing demand. Initially, it intended to provide universal low cost, low power, and low complexity wireless interface to various devices. Furthermore, it also proposed to provide the possibility of interconnecting a number of mobile devices to form a network. However, the details of network formation and operation have not yet been regulated. In this work, we will investigate Bluetooth enabled network formation issues (especially when the traffic patterns on the network are well known).

 In this thesis, we use a small indoor area network model with a wired infrastructure network installed in the wall. A number of mobiles are distributed in the area and require inter-connectivity with each other and/or the outside world through multiple gateways. Unbalanced traffic in the network may result in hotspots leading to poor network throughput. Therefore, a centralized network formation algorithm is needed for Bluetooth networks to solve this problem.

 This thesis proposes novel Network Formation based on a Traffic Distribution (NFTD) mechanism. This centralized mechanism co-ordinates the behavior of mobiles and is implemented on gateways (also called access points). It forms the network topology according to the traffic distribution so that the path length of hotspot flows can be limited in order to maximize the network capacity. Last but not least, infrastructure networks provide free high-speed links for mobiles to further increase network capacity. The proposed mechanism is a promising mechanism as supported by simulation results.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Multiple Description Lattice Vector Quantization

contributor:
Wu, Xiaolin
Electrical and Computer Engineering

subject: multiple description, lattice, vector, quantization, linear-time index

abstract:
 This thesis studies the multiple description vector quantization with lattice codebooks
(MDLVQ).

 The design of index assignment is crucial to the performance of MDLVQ. However, to our best knowledge, none of previous index assignment algorithms for MDLVQ is
optimal. In this thesis, we propose a simple linear-time index assignment algorithm for MDLVQ with any K ≥ 2 balanced descriptions. We prove, under the assumption of high resolution, that the algorithm is optimal for K = 2. The optimality holds for many commonly used good lattices of any dimensions, over the entire range of achievable central distortions given the side entropy rate. The optimality is in terms of minimizing the expected distortion given the side description loss rate and given the side entropy rate. We conjecture it to be optimal for K > 2 in general.

 We also made progress in the analysis of MDLVQ performance. The first exact closed form expression of the expected distortion was derived for K = 2. For K > 2, we improved the current asymptotic expression of the expected distortion.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Dynamic Spot Diffusing Channel - A Novel Configuration for Indoor Optical Wireless Communications

contributor:
Hranilovic, S.
Electrical and Computer Engineering

subject: dynamic spot, diffusing, channel, novel configuration, optical, wireless, communications

abstract: Some pages are blank, but are kept to satisfy the page count of the thesis.

abstract:
 Indoor optical wireless links can potentially achieve high bitrates because there is a wide and unregulated bandwidth in the optical spectrum. Moreover, optical wireless links can be implemented using simple and inexpensive devices. However, indoor optical wireless links have their own drawbacks such as limited power due to safety issues and incapability of passing thorough opaque objects, which limit their mobility, range and bandwidth and have prevented them from being used widely in commercial systems. Therefore, there has been
much effort to find new configurations for indoor optical wireless links which are able to overcome these limitations. In this thesis, a novel configuration for indoor optical wireless communication, termed the dynamic spot diffusing (DSD) channel, is proposed. In the DSD system, the transmitter sends optical signals to a small moving area on the ceiling termed a spot. The receiver receives reflections of optical signal from the spot when spot is in field of view of the receiver. This configuration is shown to achieve high bitrates and provide a good deal of mobility for users inside the room. In this work, a theoretical model for the DSD channel is proposed and the DSD channel capacity is discussed and computed. Furthermore, the DSD system design is explained and design issues are discussed in order to approach capacity. Finally, using computer simulations, achievable rates inside a room are computed and shown to be close to calculated channel capacity.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Two Dimensional QSC Mode Solvers for Arbitrary Dielectric Waveguide

contributor:
Li, Xun
Electrical and Computer Engineering

subject: two dimensional, QSC mode solvers, arbitrary dielectric waveguide, refractive index profile

abstract:
 Novel scalar and full-vectorial mode solvers based on quadratic spline collocation (QSC) method have been developed in MATLAB for optical dielectric waveguide with arbitrary two-dimensional cross-section and refractive index profile.

 Compared with the conventional finite difference mode solver in the literature and a commercial mode solver, the QSC mode solvers are simple and easy to implement in MATLAB without losing the accuracy of the mode solutions. The scalar mode solver is fast for solving weakly guiding waveguides. Three typical rib waveguides are calculated by the QSC scalar mode solver and compared with the numerical results of a finite difference scalar mode solver in the literature. The full-vectorial mode solver is capable of solving both weakly and strongly guiding waveguides. Typical numerical examples are calculated by the full-vectorial QSC mode solver and the solver is verified by comparing the results to a commercial mode solver.

 At the end of the thesis, methods of calculating leaky and radiation modes of general dielectric waveguides and possible methods of increasing the accuracy of the QSC mode solvers are proposed.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Glasgow Rent Strikes 1915:  The Struggle for Decent Housing

title: The Glasgow Rent Strikes, 1915:  Their Contribution and That of John Wheatly and Patrick Dollan to the Longer Struggle for Decent Working-Class Housing

contributor:
Heathorn, Stephen
History

subject: Glasgow

subject: working-class housing

subject: 1915 Rent Strike

subject: Rent Restrictions Act 1915

subject: Independent Labour Party (ILP)

subject: John Wheatley

subject: Patrick Dollan

subject: women leading the rent resistance

abstract:
From the 1850s Glasgow was a major industrial, commercial and mercantile city, with notoriously poor working-class housing.  During the 1915 Rent Strike many women physically resisted rent increases and prevented evictions from the tenements.  The strikes ended when the Government passed the Rent Restrictions Act 1915, which returned rents to pre-war levels. This was in response to a political and working-class struggle that challenged the rule of law.  Rather than focussing narrowly on the role of the women alone, or on the strike as inspiration for anti-capitalist resistance, the 2015 Centenary seemed opportune to examine why the Rent Strike was successful, its place in the longer struggle for decent housing, the role of the Independent Labour Party (ILP) and its leaders, and their collaborations with labour and women’s organisations.
            From the 1890s the ILP was central to labour’s campaign in elections and in fostering political collaboration with many groups representing labour.  John Wheatley and Patrick Dollan, former miners, were leaders in strengthening the ILP organisation and its community relations.  This collaborative structure supported the women leading the rent resistance in the tenements.  It was also the platform for Wheatley and Dollan, nationally and municipally, to continue their life-long work to improve the housing and living standards of working people.  Wheatley became Minister of Health in 1924 in Britain’s first Labour Government, and Dollan was Lord Provost in Glasgow’s first majority Labour Council in 1938.
            Glasgow’s systemic anti-Irish and anti-Catholic prejudice has, surprisingly, remained unexamined in relation to the Rent Strike.  Two historians claimed, without presenting evidence, that bigotry was overcome or briefly transcended.  The evidence reviewed here indicated that it did not go away, but that it had no impact on the Rent Strike as it simply offered no stimulus or opportunity to express the existing racist or religious prejudice.

abstract: Thesis

abstract: Master of Arts (MA)

abstract: Glasgow, with notoriously poor working-class housing, was a major centre in 1915 for British engineering, munitions and shipbuilding industries during the First World War.  Women who lived in Glasgow’s tenements organised rent strikes and physically resisted rent increases and evictions.  They were supported by the Independent Labour Party and the collaborations it developed before and during the war with organisations representing the interests of women and labour.  These strikes, the rent agitations in England, and the threat of industrial action in Glasgow, forced the Government to pass the Rent Restrictions Act 1915, which limited rents to pre-war levels.  Two former miners, John Wheatley and Patrick Dollan, were leaders in organising this class victory.  They recognised the Act’s limitations and then worked nationally and municipally in the longer struggle for better working-class housing.  Glasgow’s systemic anti-Irish and anti-Catholic bigotry did not disappear but played no significant role during the Rent Strike.


title: Establishing Content Validity and Transferability of a New Patient-reported Outcome Instrument for Patients with Cleft Lip and/or Palate: the CLEFT-Q

title: Content validity and transferability of the CLEFT-Q

contributor:
Klassen, Anne
Health Research Methodology

subject:
CLEFT-Q
Content validity
Transferability

abstract:
Background: Cleft lip and/or palate (CL/P) is the most common congenital craniofacial anomaly, which may negatively impact one’s appearance, health-related quality of life, and facial function. The course of treatment is intensive and multifaceted. Patients with CL/P can undergo numerous procedures, with the goal of improving their appearance or facial function. To assess the outcomes of treatment in patients, a well-developed, valid, and reliable patient-reported outcome instrument is required. The CLEFT-Q is a new patient-reported outcome instrument developed to evaluate outcomes of treatment in patients aged 8 to 29 years with cleft lip and/or palate. The purpose of this thesis was to establish content validity and transferability of the CLEFT-Q.

Methods: Study 1 of this thesis presents findings from cognitive interviews with patients and expert feedback. Patients aged between 6 and 29 years were recruited from 6 plastic surgery clinics. Healthcare providers and experts from 8 countries participated in a focus group or provided individual feedback. Input was sought on all aspects of the CLEFT-Q development, including item wording, instructions, response options, and to identify missing content. Studies 2 and 3 present findings from the translation and cultural adaptation of the CLEFT-Q to evaluate its transferability. Guidelines set forth by the International Society for Pharmacoeconomics and Outcomes Research (ISPOR) were applied.

Results: Study 1 involved 69 patients and 44 experts who reviewed the CLEFT-Q. The first draft of the CLEFT-Q consisted of 163 items measuring 12 constructs. Three rounds of interviews and expert feedback were needed to establish content validity. At the completion of the cognitive interviews and expert review, the CLEFT-Q comprised 171 items within 13 scales that measure appearance (of the face, nose, nostrils, teeth, lips, jaws, cleft lip scar), health-related quality of life (psychological, social, school, speech-related distress), and facial function (speech, eating/drinking). Studies 2 and 3 involved the translation and cultural adaptation of the CLEFT-Q from English to 6 different languages including Arabic, Catalan, Dutch, Hindi, Swedish, Turkish, and 3 Spanish language varieties (Colombian, Chilean, and Spain).

A total of 18 (12%), 18 (12%), 7 (5%), and 4 (3%) items were difficult to translate during the forward translations for the Arabic, Swedish, Dutch, and Hindi versions respectively. Among the Spanish varieties (study 3) only 10 (7%) items were difficult to translate into Chilean. Comparison of the back translation to the source language version of the CLEFT-Q identified that the meaning of 40 (26%), 17 (11%), 9 (6%), and 5 (3%) items in the Turkish, Arabic, Hindi, and Swedish translations respectively had changed and required re-translation, and none were changed for the Dutch translation in study 2. Similarly, in study 3, back translations identified 23 (15%), 21 (13%), 12 (8%), and 10 (6%) items in the Colombian, Catalan, Chilean, and Spanish (Spain) versions respectively whose meanings were changed.

Study 2 cognitive debriefing interview participants were mostly below 20 years of age (n= 36, 88%) with CL/P (n=30, 73%). Participants in study 3 were primarily male (n=14, 67%) diagnosed with CL/P (n=17, 81%). Overall, participants in the cognitive debriefing interviews described the CLEFT-Q as understandable and easy to complete.

Conclusion: This thesis presents evidence of the CLEFT-Q’s content validity and transferability. After the completion of study 1, no changes were required to the original CLEFT-Q conceptual framework; however, cognitive interviews and expert review allowed us to identify items that required re-wording, re-conceptualizing, to removal, or addition. Finally, the process of translating and culturally adapting the CLEFT-Q in studies 2 and 3 was useful for finalizing the CLEFT-Q scales, and provided evidence of its transferability to other contexts.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: Background: Treatment of cleft lip and/or palate (CL/P) is intensive and involves multiple procedures to improve ones appearance or facial function. To assess outcomes of treatment in patients with CL/P, a well-developed, valid, and reliable patient-reported outcome instrument is required. The purpose of this thesis was to establish content validity and transferability of the CLEFT-Q. Methods: Cognitive interviews with patients and expert feedback were obtained in Study 1. Input was sought on the CLEFT-Q item wording, instructions, response options, and to identify missing content. Studies 2 and 3 involved the translation and cultural adaptation of the CLEFT-Q to evaluate its transferability. Results: Three rounds of cognitive interviews with patients and expert feedback were needed to establish content validity of the CLEFT-Q in study 1. Studies 2 and 3 involved the translation and cultural adaptation of the CLEFT-Q from English to 6 different languages including Arabic, Catalan, Dutch, Hindi, Swedish, Turkish, and 3 Spanish language varieties (Colombian, Chilean, and Spain). Translation and cultural adaptation processes provided evidence of the CLEFT-Qs transferability. Conclusion: This thesis presents evidence of the CLEFT-Q’s content validity and transferability.


title: The Integration of Annular Thermoelectric Generators in a Heat Exchanger for Waste Heat Recovery Applications

contributor:
Cotton, James
Mechanical Engineering

subject:
Thermoelectric Generators
Waste Heat Recovery

abstract:
Growing concerns regarding climate change, the increase in demand for energy and the efficient utilization of energy have become of major interest in applications of heating and power generation. A large portion of the energy input to these applications is lost, due to their typical inefficiencies, in the form of waste thermal energy which, if captured and utilized, can offer an abundant source of energy for electricity generation and heating purposes. The use of thermoelectric generators (TEGs) of different designs in waste heat recovery applications has been pursued over the past few decades as the generation of electrical power using TEGs has become viable compared to other conventional systems at low temperatures. This study focuses on the implementation of an annular design for integrated TEG modules in a heat exchanger device for waste heat recovery and the investigation of the effect of different TEG design parameters on the device performance.
The integration of the annular TEG design in the heat exchanger was studied using a developed numerical model to investigate the interaction between the heat transfer and the thermoelectric effects and evaluate the performance under specific operating conditions. The heat transferred from the exhaust to the water flow through the TEGs was modelled using a thermal network for the heat flow, coupled with an electrical circuit for the power output. The model was validated using experimental results of the first generation of the TEG device with good agreement (3-6 %) between the predicted and measured performance results: power output, efficiency and the exhaust and water flow temperatures.
With the objectives of maximizing the power output and improving the power characteristics, a half annular TEG design was presented. It was able to generate the same power output with double the voltage and half the current, thus improved the power characteristics required for functional operation, compared to the full annular design. The effect of the annular TEG design dimensions on the device performance was studied for a multi-row heat exchanger using the numerical model. The results showed that a maximum power output can be obtained at optimum TEG diameter ratio and thickness.
In addition, the TEGs performance was studied under different electrical connection configurations in series and in parallel. The series connection between TEG rows showed better power output characteristics with lower current output, minimal power loss due to temperature mismatch and higher voltage output. The effect of heat exchanger design considerations such as the axial heat conduction was also investigated using the numerical model and the results were compared with an ANSYS model for verification. Good agreement was demonstrated and the results showed a decrease in the total power output of multiple TEG rows when axial conduction of heat was allowed between the TEGs hot-side surfaces in the heat exchanger.
A dimensions map was created for annular TEGs integrated in a heat exchanger combining the effects of varying the TEG diameter ratio and thickness on the power output. Further, a dimensionless design parameter (β) was introduced to locate the maximum power region on the map. Using the map as a design tool, the dimensions of the annular TEG modules in a heat exchanger were determined to maximize the power output under a typical current output constraint in order to improve the system power characteristics. Using the map, it was shown that the current output could be reduced by 46 % of its value at the maximum power available on the map and the resultant power output could be maintained at 98 % of its maximum value. This also resulted in a 48% reduction in the TEG material volume and an increased voltage output of the device. As a result, the power output was maximized, the current output was limited to reduce losses in the power management system components and material volume reduction was achieved which would increase the device power density and reduce its overall cost.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: STUDY OF FULLY-MIXED HYBRID THERMAL ENERGY STORAGE WITH PHASE CHANGE MATERIALS FOR SOLAR HEATING APPLICATIONS

contributor:
Lightstone, Marilyn
Mechanical Engineering

subject:
Thermal Energy Storage
Phase Change Materials
Solar Heating
Cascaded Storage

abstract:
A novel design of hybrid thermal energy storage (HTES) using Phase Change Material (PCM) was evaluated using a mathematical model. Both single and multi-tank (cascaded) storage were explored to span small to large-scale applications (200-1600 litres). The storage element was based on the concept of a fully-mixed modular tank which is charged and discharged indirectly using two immersed coil heat exchangers situated at the bottom and top of the tank. A three-node model was developed to simulate different thermal behaviors during the operation of the storage element. Experiments were conducted on full-scale 200-l single-tank sensible heat storage (SHS) and hybrid thermal energy storage (HTES) to provide validation for the mathematical model. The HTES incorporated rectangular PCM modules submerged in the water tank. Satisfactory agreement was found between the numerical results and the experimental results obtained by Mather (2000) on single and multi-tank SHS. In addition, good agreement was noticed with the experiments performed by the author on single-tank SHS and HTES at McMaster University. The developed model was found to provide high levels of accuracy in simulating different operation conditions of the proposed design of storage element as well as computational efficiency.
A parametric study was undertaken to investigate the potential benefits of the HTES over the SHS, operating under idealistic conditions. The HTES can perform at least two times better than the SHS with the same volume. The PCM volume fraction, melting temperature and properties were found to have critical impact on the storage gains of the HTES. All the parameters must be adjusted such that: (1) the thermal resistance of the storage element is minimized, and (2) most of the energy exchange with the storage element takes place in the latent heat form.
The performance of the single-tank HTES was evaluated numerically while operating in a solar thermal domestic hot water (DHW) system for a single-family residence. The PCM parameters were selected to maximize the solar fraction during the operation on a typical spring day in Toronto. The use of the HTES can reduce the tank volume by 50% compared to the matched size of the SHS tank. However, the HTES was found to underperform the SHS when the system was operated in different days with different solar irradiation intensities. The effect of different draw patterns was also investigated. The results indicated that thermal storage is needed only when the energy demand is out-of-phase with the energy supply. For the same daily hot water demand, different consumption profiles; ex. dominant morning, dominant evening, dominant night and dispersed consumptions, showed slight impact on the performance of the system.
The concept of multi-tank (cascaded) HTES storage was explored for medium/large scale solar heating applications such as for restaurants, motels, and multi-family residences. The design was based on the series connection of modular tanks through the bottom and top heat exchangers. Each individual tank had a PCM with different melting temperature. The results showed that the cascaded storage system outperformed the single-tank system with the same total volume as a result of the high levels of sequential or tank-to-tank stratification. The use of the cascaded HTES resulted in slight improvement in the solar fraction of the system.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: THE ASSOCIATION BETWEEN DELAYED ACTIVATION OF RAPID RESPONSE TEAMS AND PATIENT MORTALITY AND MORBIDITY

contributor:
Thabane, Lehana
Fox-Robichaud, Alison
Health Research Methodology

subject:
rapid response team
time factors
mortality
intensive care
rapid response systems
patient safety

abstract:
Objectives: The objective of this thesis is to explore the association between delayed rapid response team activation and patient mortality and morbidity in adult in-patients.
Methods: Study 1 presents a protocol for a systematic review of literature regarding the association of delayed activation of rapid response teams and patient outcomes. Study 2 contains the results of the conducted systematic review, performing a search of the literature to critically appraise, aggregate, and present a narrative synthesis of included studies. The final study examines the association between delayed rapid response team activation and hospital mortality, ICU transfer, and cardiopulmonary arrest risk in a retrospective observational cohort study conducted as part of the “Hospital without Code Blues” initiative at Hamilton Health Sciences.
Results: Studies included in the systematic review report an association between delayed activation and patient mortality and ICU transfer odds. Results of study three find that these delays may not be associated with patient mortality, but are significantly associated with ICU transfer events and a composite outcome of patient in-hospital mortality, ICU transfer, and cardiopulmonary arrest. Overall, patients experiencing a delayed rapid response team activation were at greater odds of experiencing a negative event during their course of stay in hospital.
Conclusions: This thesis presents findings that suggest delayed activation of rapid response teams is associated with an increase in patient mortality and ICU transfers. Increased durations of delay are associated with increased odds of experiencing the above events.

abstract: Thesis

abstract: Master of Science (MSc)


title: Design, Implementation, and Testing of a High-Power Electrified Powertrain for an American Muscle Car

contributor:
Emadi, Ali
Mechanical Engineering

subject:
Hybrid Vehicle
Vehicle Electrification
Performance Hybrid
Powertrain Electrification
Muscle Car

abstract:
This thesis outlines the design and implementation process of an electrified powertrain for use in an American muscle car. Designed as McMaster University's entrant to the EcoCAR 3 Advanced Vehicle Technology Competition (AVTC), an electrified powertrain was developed to provide a Chevrolet Camaro with the performance expected by the American muscle car market while maintaining ever increasing fuel economy regulations. A background of current trends in vehicle electrification, including the prominent market segments experiencing these trends, will be explored along with the history of the classic and modern American muscle car's technical specifications. Following an investigation into existing vehicle electrification trends, the selected hybrid architecture will be discussed.

The process of converting a conventional combustion powertrain into a series-parallel hybrid electric powertrain will be explored from the component-level through to full system design. Following a review of the design process for the powertrain, a high-level testing plan will be proposed using a number of test cells available within the facility. This plan will begin at the component-level exploring specific areas of potential complication and move up to complete system-level testing of powertrain functionality.

abstract: Thesis

abstract: Master of Applied Science (MASc)

abstract:
Until recently, hybrid electric vehicles have tended to be available in a fairly limited market segment with few offerings for performance-oriented vehicle customers. The introduction of high performance hybrid vehicles suggests that this trend is likely to change. Increasingly more stringent fuel economy and emissions standards means that performance vehicle segments such as American muscle cars must adopt new technologies to retain their performance characteristics. Hybrid powertrains are one solution to providing and improving on the iconic performance of American muscle while meeting future regulatory changes.

The addition of a number of electrified components to a gasoline powertrain can assist in achieving desired performance while reducing fuel economy. This thesis investigates the detailed design process adopted to make these modifications while maintaining the functionality expected by muscle car owners. After the design and assembly of the hybrid muscle car powertrain, a specific testing plan was laid out to ensure that the system is capable of sustaining the expected power output. This design and testing process can help introduce new hybrid vehicles to the market which are capable of meeting both the upcoming fuel economy regulations as well as the ongoing performance expectations of the muscle car market.


title: Maximum Rate of Growth of Enstrophy in the Navier-Stokes System on 2D Bounded Domains

contributor:
Protas, Bartosz
Computational Engineering and Science

subject:
Chebyshev Method
Enstrophy
Navier-Stokes
Numerical Optimization
Vorticity-Streamfunction Formulation

abstract: One of the key open problems in the field of theoretical fluid mechanics concerns the possibility of the singularity formation in solutions of the 3D Navier-Stokes system in finite time. This phenomenon is associated with the behaviour of the enstrophy, which is an L2 norm of the vorticity and must become unbounded if such a singularity occurs. Although there is no blow-up in the 2D Navier-Stokes equation, we would like to investigate how much enstrophy can a planar incompressible flow in a bounded domain produce given certain initial enstrophy. We address this issue by formulating an optimization problem in which the time derivative of the enstrophy serves as the objective functional and solve it using tools of the optimization theory and calculus of variations. We propose an efficient computational approach which is based on the iterative steepest-ascent procedure. In addition, we introduce an easy-to-implement method of computing the gradient of the objective functional. Finally, we present computational results addressing the key question of this project and provide numerical evidence that the maximum enstrophy growth exhibits the scaling dE/dt ~ C*E*E for C>0 and very small E. All computations are performed using the Chebyshev spectral method.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: For many decades, scientists have been investigating fundamental aspects of the Navier-Stokes equation, a central mathematical model arising in fluid mechanics. Although the equation is widely used by engineers to describe numerous flow phenomena, it is still an open question whether the Navier-Stokes system always admits physically meaningful solutions. To address this issue, we want to explore its mathematical aspects deeper by analyzing the behaviour of the enstrophy, which is a quantity associated with the vorticity of the flow and a convenient measure of the regularity of the solution. In this study, we consider a planar and incompressible flow bounded by solid walls. Using basic tools of mathematical analysis and optimization theory, we propose a computational method enabling us to find out how much enstrophy can such a flow produce instantaneously. We present numerical evidence that this instantaneous growth of enstrophy has a well-defined asymptotic behavior, which is consistent with physical assumptions.


title: SYNTHETIC, STRUCTURAL AND COMPUTATIONAL STUDIES OF ORGANO-CHALCOGEN SUPRAMOLECULAR BUILDING BLOCKS

title: Organo-chalcogen Supramolecular Building Blocks

contributor:
Vargas-Baca, Ignacio
Chemistry

subject:
Supramolecular Chemistry
Inorganic Chemistry
Heterocycles
Synthesis
Structural Characterization
Main Group Chemistry

abstract:
Previous studies of supramolecular association through chalcogen-centred secondary bonding interactions (SBIs) demonstrated the versatility of 1,2,5-telluradiazoles and their annulated congeners, the benzo-2,1,3-telluradiazoles, as supramolecular building blocks. Key to the properties of those compounds is their propensity to undergo auto-association through the [Te-N]2 supramolecular synthon leading to dimers or supramolecular ribbon polymers. Moderate steric repulsion induces structural distortions of [Te-N]2 without dissociation and, in doing so, enables properties of practical interest such as chromotropism and second-order non-linear optical responses. However, moisture sensitivity discourages wide-spread application of these compounds. While being more tolerant of the atmosphere, the analogous selenadiazoles form weaker intermolecular interactions. Using a combined experimental and computational approach, this thesis investigates methods by which the selenium-centred supramolecular interactions can be enhanced and applied in the construction of supramolecular architectures.
The quantum mechanical description of the SBIs formed by 1,2,5-chalcogenadiazoles was updated with the application of modern dispersion corrections to relativistic density functional theory calculations (PBE-D3, ZORA). While in all cases the dispersion effect on optimized SBI distances is small (< 0.03 Å), the dispersion corrections to the calculated interaction energy range from 6 to 10 kJ mol-1 and increase with the weight of the chalcogen. The total interaction energy increases faster, however, therefore the relative weight of dispersion for the telluradiazole (10%) is significantly less than for the sulfur analogue (40%).
The same dispersion-corrected functional was applied to the identification of the secondary ions observed in the Laser Desorption Ionization mass spectrum of benzotelluradiazoles. The most stable structure of the [2M+H]+ ion was shown to feature the [Te-N]2 supramolecular synthon and would be preferred over alternatives held by hydrogen bonding alone, one TeN SBI, a combination of the two or -stacking. The [2M]+ would also feature the [Te-N]2 supramolecular synthon. Shortening of the TeN distances in these ions implies that electron withdrawing groups strengthen the SBIs.
The updated computational method was also applied to characterize the bonding in the adducts of a N-heterocyclic carbene with benzo-2,1,3-telluradiazole and 3,4-dicyano-2,1,5-telluradiazole recently prepared by the Zibarev group. The long TeC distances (2.53 and 2.34 Å) correspond to fractional bond orders (<0.6) but display a significant covalent character. Attachment of the carbene nearly erases the remaining σ-hole on tellurium, raises the LUMO energy and consequently prevents the dimerization of these adducts, in contrast to what has been observed with the pyridine and DMSO adducts of other telluradiazoles.
Benzo-2,1,3-selenenadiazole reacted with boranes (BR3, R = Ph, F, Cl, Br) yielding 1:1 (R = Ph, F, Cl, Br) and 1:2 (R = Cl) adducts. The crystal structure the BPh3 adduct features molecules organized in pairs connected by long SeC SBIs but no SeN SBIs. The BF3 and BCl3 1:1 adducts dimerize forming the [Se-N]2 supramolecular synthon. In contrast, the BBr3 adduct does not dimerize although SeBr, BrBr SBIs are formed through the lattice. The 1:2 adduct displays SeCl SBIs accompanied by distortion of the N-B-Cl bond angle due to the enhanced electrophilicity of the chalcogen. DFT calculations were performed to evaluate the energies of dimerization of the 1:1 adducts, the calculated SBI energies are greater than those for the dimer of the parent heterocycle (benzo-2,1,3-selenadiazole, 3b).
The products of the combination of benzo-2,1,3-selenenadiazole with chloride salts of divalent Mn, Fe, Co, Ni, and Cd crystallized from DMSO in two distinct structural types. While the smaller ions (FeII, CoII and NiII) form infinite chains of metal atoms N,N’-bridged by the heterocycle΄ the larger ions (MnII and CdII) stabilize infinite chains of metal atoms bridged by 2 halide ions. In the latter case, two heterocycle molecules cap each metal ion and are able to establish a link to the next chain in the lattice through the [Se‑N]2 supramolecular synthon.  Despite the large (>9.2 Å) distance between [M(-Cl)2]∞ chains, the manganese derivative is only paramagnetic, not ferromagnetic. Symmetry-broken DFT calculations for small models were unable to quantitatively reproduce the measured couplings (J) but do indicate that the heterocycle acquires significant spin density in the MnII compound enabling paramagnetic coupling through the [Se‑N]2 supramolecular synthon.
General methods for the synthesis of N-alkylated selenadiazolium cations were investigated. Methyl, iso-propyl and tert-butyl benzo-2,1,3-selenadiazolium cations were prepared by direct alkylation or cyclo-condensation of the alkyl-phenylenediamine with selenous acid. While the former reaction only proceeds with the primary and tertiary alkyl iodides, the latter is very efficient. Difficulties reported in earlier literature are attributable to the formation of adducts of benzoselenadiazole with its alkylated cations and side reactions initiated by aerobic oxidation of iodide. However, the cations themselves are resilient to oxidation and stable in acidic to neutral aqueous media. X-ray crystallography was used in the identification and characterization of the following compounds: [C6H4N2(R)Se]+X-, (R = CH(CH3)2, C(CH3)3; X = I-, I3-), [C6H4N2(CH3)Se]+I-, and [C6H4N2Se][C6H4N2(CH3)Se]2I2. Formation of SeN SBIs was only observed in the last structure because anion binding to selenium is stronger. The relative strengths of those forces and the structural preferences they enforce were assessed with DFT-D3 calculations supplemented by AIM analyses of the electron density.
The methods developed for the preparation of N-alkyl benzoselenadiazolium cations were extended to the syntheses of dications intended for use as building blocks of supramolecular polymers. The structure of several salts was established by single-crystal X-ray diffraction. [H4C6NSeN-CH2-CH2-NSeNC6H4]Cl2 crystallized forming a macrocyclic structure in which two dications are bridged by SeCl SBIs; a third halide anion sits at the centre of the macrocycle. [1,2-(H4C6NSeN)2-C6H10]Cl2 features two selenadiazolium cations bridged by a 1‑(R),2‑(R)‑substituted cyclohexane and short SeCl SBIs.  [1,4-(H4C6NSeN-CH2)2-C6H4](BF4)2, featuring a p-xylene bridge, crystallizes in two pseudopolymorphs; with dications in anti or syn conformations making SeF contacts. [H4C6NSeN-CH2-CH2-NSeNC6H4](CF3SO3)2 does dimerize though the [Se-N]2 supramolecular synthon, although SeO interactions with the anions cap the second selenium atom. In contrast, [H4C6NSeN-CH2-CH2-CH2-NSeNC6H4](CF3SO3)2 only displays SeO contacts.
An oligonucleotide analogue containing N-substituted selenadiazolium cations was designed to create foldamers with structures controlled by main-group secondary bonding. The target structures take advantage of the methods developed in this thesis for the functionalization of selenadiazoles and is meant to be compatible with automated methods for oligonucleotide synthesis. The proposed synthesis begins with the preparation of 1-(α,β)-O-methyl-2-deoxy-D-ribose, which was chlorinated and treated with phenylenediamine. High-resolution mass spectrometry confirmed the attachment of the diamine to the ribose, however, the yield was too low to continue this synthetic project.
A ground-breaking development in the application of secondary bonding in supramolecular chemistry is the discovery of the reversible auto-association of iso-tellurazole N-oxides through TeO SBIs into annular structures. These rings are persistent in solution and behave as actual macrocycles able to complex transition metal ions, form adducts with fullerenes, and host small molecules. Single-crystal X-ray diffraction was critical to the characterization of these structures and required careful disorder modelling for tetrahydrofuran molecules included in a macrocyclic hexamer and the occupational disorder of CH2Cl2 and BF4- anions due to metal depletion in the crystal of a PdII complex.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract:
Supramolecular chemistry is a prominent area of research that pursues the construction of large structures by the spontaneous assembly and organization of molecular building blocks. Its fundamental premise is that the judicious use of intermolecular forces allows the design of a structure and control of its properties. Most of the work in supramolecular chemistry has relied on hydrogen atoms bridging molecules and the bonding of metal ions to atoms rich in electrons. This thesis pursued the use of a different type of intermolecular force, termed “secondary bonding”, which is characteristic of the heaviest elements at the right of the periodic table (the “main-group” of elements).
Previous work at McMaster demonstrated that cyclic molecules containing carbon, nitrogen and tellurium were particularly efficient as supramolecular building blocks. However, they are easily degraded by atmospheric water, this fact severely limits practical applications of these compounds.
In this thesis, the tellurium atoms are replaced by selenium, a lighter element in the same family. The resulting molecules are more tolerant of atmospheric conditions but form weaker intermolecular links. Through a combination of quantum mechanical, synthetic, spectroscopic and structural studies, it is shown that certain modifications to the molecular structure increase the affinity of the selenium atoms for electrons. In this way, it is possible to strengthen the intermolecular interactions and promote the spontaneous assembly of supramolecular structures.
These investigations eminently fall in the category of fundamental research but have broad-reaching implications for practical applications in optical and electronic technologies.


title: Lights in Dark Places: Inferring the Milky Way Mass Profile using Galactic Satellites and Hierarchical Bayes

contributor:
Harris, William
Physics and Astronomy

subject:
Milky Way
Bayesian
Galaxy
Astronomy
Astrostatistics
dark matter

abstract:
Despite valiant effort by astronomers, the mass of the Milky Way (MW) Galaxy is poorly constrained, with estimates varying by a factor of two. A range of techniques have been developed and different types of data have been used to estimate the MW’s mass. One of the most promising and popular techniques is to use the velocity and position information of satellite objects orbiting the Galaxy to infer the gravitational potential, and thus the total mass. Using these satellites, or Galactic tracers, presents a number of challenges: 1) much
of the tracer velocity data are incomplete (i.e. only line-of-sight velocities have been measured), 2) our position in the Galaxy complicates how we quantify measurement uncertainties of mass estimates, and 3) the amount of available tracer data at large distances, where the dark matter halo dominates, is small. The latter challenge will improve with current and upcoming observational programs such as Gaia and the Large Synoptic Survey Telescope (LSST), but to properly prepare for these data sets we must overcome the former two. In this thesis work, we have created a hierarchical Bayesian framework to estimate the Galactic mass profile. The method includes incomplete and complete data simultaneously, and incorporates measurement uncertainties through a measurement model. The physical model relies on a distribution function for the tracers that allows the tracer and dark matter to have different spatial density profiles. When the hierarchical Bayesian model is confronted with the kinematic data from satellites, a posterior distribution is acquired and used to infer the mass and mass profile of the Galaxy. This thesis walks through the incremental steps that led to the development of the hierarchical Bayesian method, and presents MW mass estimates when the method is applied to the MW’s globular cluster population. Our best estimate of the MW’s virial mass is 0.87 (0.67, 1.09) x 10^(12) solar masses. We also present preliminary results from a blind test on hydrodynamical, cosmological computer-simulated MW-type galaxies from the McMaster Unbiased Galaxy Simulations. These results suggest our method may be able to reliably recover the virial mass of the Galaxy.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)