Reduction theory for systems with symmetry deals with the problem of understanding dynamics on a manifold with an action of a Lie group. In geometric mechanics, this problem can be formulated in the Lagrangian, Hamiltonian or affine connection frameworks. While the Lagrangian and Hamiltonian formulations have been well developed, the results obtained in these setups are based on variational principles and symplectic geometry. These methods cannot be used directly in the affine connection formulation unless additional structure is available. In this thesis, a manifold with an arbitrary affine connection is considered, and the geodesic spray associated with the connection is studied in the presence of a Lie group action. In particular, results are obtained that provide insight into the structure of the reduced dynamics associated with the given invariant affine connection. The geometry of the frame bundle of the given manifold is used to provide an intrinsic description of the geodesic spray. A fundamental relationship between the geodesic spray, the tangent lift and the vertical lift of the symmetric product is obtained, which provides a key to understanding reduction in this formulation. / Thesis (Ph.D, Mathematics & Statistics) -- Queen's University, 2007-07-24 01:00:05.635

Noise reduction aims to improve the quality of noisy speech by suppressing the background noise in the signal. However, there is always a tradeoff between noise reduction and signal distortion--more noise reduction is always accompanied by more signal distortion. An evaluation of the intelligibility of speech processed by several noise reduction algorithms in [23] showed that most noise reduction algorithms were not successful in improving the intelligibility of noisy speech. In this thesis, we aim to utilize acoustic-phonetic knowledge to enhance the intelligibility of noise-reduced speech. Acoustic-phonetics studies the characteristics of speech and the acoustic cues that are important for speech intelligibility. We considered the following questions: what is the noise reduction algorithm that we should use, what are the acoustic cues that should be targeted, and how to incorporate this information into the design of the noise reduction system. A Bayesian noise reduction method similar to the one proposed by Ephraim and Malah in [16] is employed. We first evaluate the goodness-of-fit of several parametric PDF models to the empirical speech data. For classified speech, we find that the Rayleigh and Gamma. with a fixed shape parameter of 5, model the speech spectral amplitude equally well. The Gamma-MAP and Gamma-MMSE estimators are derived. The subjective and objective performances of these estimators are then compared. We also propose to apply a class-based cue-enhancement, similar to those performed in [21]. The processing directly manipulates the acoustic cues known to be important for speech intelligibility. We assume that the system has the sound class information of the input speech. The scheme aims to enhance the interclass and intraclass distinction of speech sounds. The intelligibility of speech processed by the proposed system is then compared to the intelligibility of speech processed by the Rayleigh-MMSE estimator [16] The intelligibility evaluation shows that the proposed scheme enhances the detection of plosive and fricative sounds. However, it does not help in the intraclass discrimination of plosive sounds, and more tests need to be done to evaluate whether intraclass discrimination of fricatives is improved. The proposed scheme deteriorates the detection of nasal and affricate sounds. / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2009-08-24 21:32:48.966

The anodic polarization of Ni electrode in 0.5 M aqueous KOH solution at various polarization potential (Ep), time (tp) and temperature (T) values leads to the formation of β-Ni(OH)2 films. The growth of the hydroxide layers are irreversible and cannot be reduced electrochemically to metallic Ni. The hydroxide layer becomes thicker at higher values of Ep and/or tp and/or T. The thickness of β-Ni(OH)2 hydroxide were determined using ex–situ XPS and depth–profile techniques. Application of the oxide growth theories to our data indicate that the development of the β-Ni(OH)2 layer follows inverse logarithmic growth kinetics. The driving force of the process is the strong electric field that is established across the oxide layer. The strength of electric field is in the range of 0.015 – 0.197 x 109 V m–1. The oxidation mechanism of the Ni(II) surface compound to Ni(III) is electrochemically irreversible and the process is treated according to Randles–Sevcik equation. A linear relation was determined between the peak current density (jp) and the square root of the potential scan rate (v1/2) for the entire range of Ep, tp and T. The diffusion coefficient (D) values calculated for anodic and cathodic processes are 8.1 ± 0.2 x 10–12 and 4.3 ± 0.2 x 10–12 cm2 s–1, respectively. The activation energy (Ea) values for the diffusion process are 23 ± 2 kJ mol–1 (anodic) and 26 ± 2 kJ mol–1 (cathodic). The D and Ea values calculated from chronoamperometry measurements are comparable with those calculated from jp vs. v1/2 plots. The electro–reduction of PtO electrochemically pre–formed on Pt electrode in 0.5 M aqueous H2SO4 solution was also investigated. A well–controlled reduction conditions (Er, tr and T) were applied to determine the amount of the reduced PtO oxide. The reduction of the PtO requires much less time once ca. 1 monolayer (ML) of the oxide has been removed (ca. 1 ML of PtO remains). As expected, the longer tr and/or lower Er values, the greater the amount of the reduced oxide and consequently the smaller the amount of the remaining PtO oxide. / Thesis (Ph.D, Chemistry) -- Queen's University, 2011-02-08 10:58:54.114

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This thesis explored the opportunities to reduce energy demand and renewable energy feasibility at an off-grid science “community” called the Experimental Lakes Area (ELA) in Ontario. Being off-grid, ELA is completely dependent on diesel and propane fuel supply for all its electrical and heating needs, which makes ELA vulnerable to fluctuating fuel prices. As a result ELA emits a large amount of greenhouse gases (GHG) for its size. Energy efficiency and renewable energy technologies can reduce energy consumption and consequently energy cost, as well as GHG. Energy efficiency was very important to ELA due to the elevated fuel costs at this remote location. Minor upgrades to lighting, equipment and building envelope were able to reduce energy costs and reduce load. Efficient energy saving measures were recommended that save on operating and maintenance costs, namely, changing to LED lights, replacing old equipment like refrigerators and downsizing of ice makers. This resulted in a 4.8% load reduction and subsequently reduced the initial capital cost for biomass by $27,000, by $49,500 for wind power and by $136,500 for solar power. Many alternative energies show promise as potential energy sources to reduce the diesel and propane consumption at ELA including wind energy, solar heating and bio-mass. A biomass based CHP system using the existing diesel generators as back-up has the shortest pay back period of the technologies modeled. The biomass based CHP system has a pay back period of 4.1 years at $0.80 per liter of diesel, as diesel price approaches $ 2.00 per liter the pay back period reduces to 0.9 years, 50% the generation cost compared to present generation costs. Biomass has been successfully tried and tested in many off-grid communities particularly in a small-scale off-grid setting in North America and internationally. Also, the site specific solar and wind data show that ELA has potential to harvest renewable resources and produce heat and power at competitive rates compared to diesel and propane.

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As the HIV/AIDS epidemic in the United States nears the end of its third decade, stakeholders have begun to sift through the previous experiences in prevention in order to assess progress as well as plan the next steps in this fight. The purpose of this study is aimed at understanding the factors which may affect unprotected intercourse. It is hypothesized that for men who have sex with men (MSM) there is an association between having a discussion about their HIV status and high-risk sexual behaviors. A secondary analysis was conducted using data from the National HIV Behavioral Surveillance (NHBS) System. Binary logistic regression was conducted to determine the degree of association of the dependent variables; unprotected receptive anal intercourse (URAI) with a main partner, URAI with a non-main partner, unprotected insertive anal intercourse (UIAI) with a main partner and UIAI with a non-main partner, with the independent variables of discussion of HIV status, age, race, educational attainment, number of partners and HIV status. When assessing the association between the discussion of HIV status with both URAI and UAIA it was found that discussion of HIV status was a non-significant factor. Despite the non-significant findings in relations to the hypotheses, being Black was found to be a significant predictor of URAI and UAIA with main partners in the logistic regression models. Having a positive serostatus and having 5 or more sexual partners proved to be significant risk factors for URAI and UIAI with a non-main partner, while being Black was found to be a protective factor.

Lemieux recently proposed a new approach that studies randomized quasi-Monte Carlothrough dependency concepts. By analyzing the dependency structure of a rank-1 lattice,Lemieux proposed a copula-based criterion with which we can find a ???good generator??? for the lattice. One drawback of the criterion is that it assumes that a given function can be well approximated by a bilinear function. It is not clear if this assumption holds in general. In this thesis, we assess the validity and robustness of the copula-based criterion. We dothis by working with bilinear functions, some practical problems such as Asian option pricing, and perfectly non-bilinear functions. We use the quasi-regression technique to study how bilinear a given function is. Beside assessing the validity of the bilinear assumption, we proposed the bilinear regression based criterion which combines the quasi-regression and the copula-based criterion. We extensively test the two criteria by comparing them to other well known criteria, such as the spectral test through numerical experiments. We find that the copula criterion can reduce the error size by a factor of 2 when the functionis bilinear. We also find that the copula-based criterion shows competitive results evenwhen a given function does not satisfy the bilinear assumption. We also see that our newly introduced BR criterion is competitive compared to well-known criteria.