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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
411

Essays in Asset Pricing

Ochoa-Coloma, Juan Marcelo January 2013 (has links)
<p>The three essays in this dissertation explore the role of fluctuations in aggregate volatility and global temperature as sources of systemic risk. </p><p>The first essay proposes a production-based asset pricing model and provides empirical evidence suggesting that compensation for volatility risk is closely related to an unexplored characteristic of a firm, namely, its reliance on skilled labor. I propose a model in which aggregate growth has time-varying volatility, and linear adjustment costs in labor increase with the skill of a worker. The model predicts that expected returns increase with a firm's reliance on skilled labor, as well as compensation for fluctuations in aggregate uncertainty. Consequently, a rise in aggregate uncertainty predicts an increase in expected returns as well as in cautiousness in hiring and firing. This impact is larger for firms with a high share of skilled workers because their labor is more costly to adjust. I empirically test the implications of the model using occupational estimates to construct a measure of a firm's reliance on skilled labor, and find a positive and statistically significant cross-sectional relation between the reliance on skilled labor and expected returns. Empirical estimates also show that an increase in aggregate uncertainty leads to a rise in expected returns, and this impact is larger for firms which rely heavily on skilled labor; thereby, a firm's exposure to aggregate volatility is positively related to its reliance on skilled labor.</p><p>In the second and third essay, co-authored with Ravi Bansal, we explore the impact of global temperature on financial markets and the macroeconomy. In tho second essay we explore if temperature is an aggregate risk factor that adversely affects economic growth. First, using data on global capital markets we find that the risk-exposure of these returns to temperature shocks, i.e., their temperature beta, is a highly significant variable in accounting for cross-sectional differences in expected returns. Second, using a panel of countries we show that GDP growth is negatively related to global temperature, suggesting that temperature can be a source of aggregate risk. To interpret the empirical evidence, we present a quantitative consumption-based long-run risks model that quantitatively accounts for the observed cross-sectional differences in temperature betas, the compensation for temperature risk, and the connection between aggregate growth and temperature risks. </p><p>The last essay proposes a general equilibrium model that simultaneously models the world economy and global climate to understand the impact of climate change on the economy. We use this model to evaluate the role of temperature in determining asset prices, and to compute utility-based welfare costs as well as dollar costs of insuring against temperature fluctuations. We find that the temperature related utility-costs are about 0.78% of consumption, and the total dollar costs of completely insuring against temperature variation are 2.46% of world GDP. If we allow for temperature-triggered natural disasters to impact growth, insuring against temperature variation raise to 5.47% of world GDP.</p> / Dissertation
412

A time-dependent spectral point spread function for the OSIRIS optical spectrograph

2013 May 1900 (has links)
The primary goal of the recently formed Absorption Cross Sections of Ozone (ACSO) Commission is to establish an international standard for the ozone cross section used in the retrieval of atmospheric ozone number density profiles. The Canadian instrument OSIRIS onboard the Swedish spacecraft Odin has produced high quality ozone profiles since 2002, and as such the OSIRIS research team has been asked to contribute to the ACSO Commission by evaluating the impact of implementing different ozone cross sections into SASKTRAN, the radiative transfer model used in the retrieval of OSIRIS ozone profiles. Preliminary analysis revealed that the current state of the OSIRIS spectral point spread function, an array of values describing the dispersion of light within OSIRIS, would make such an evaluation difficult. Specifically, the current spectral point spread function is time-independent and therefore unable to account for any changes in the optics introduced by changes in the operational environment of the instrument. Such a situation introduces systematic errors when modelling the atmosphere as seen by OSIRIS, errors that impact the quality of the ozone number density profiles retrieved from OSIRIS measurements and make it difficult to accurately evaluate the impact of using different ozone cross sections within the SASKTRAN model. To eliminate these errors a method is developed to calculate, for the 310-350 nm wavelength range, a unique spectral point spread function for every scan in the OSIRIS mission history, the end result of which is a time-dependent spectral point spread function. The development of a modelling equation is then presented, which allows for any noise present in the time-dependent spectral point spread function to be reduced and relates the spectral point spread function to measured satellite parameters. Implementing this modelled time-dependent spectral point spread function into OSIRIS ozone retrieval algorithms is shown to improve all OSIRIS ozone profiles by 1-2% for tangent altitudes of 35-48 km. Analysis is also presented that reveals a previously unaccounted for temperature-dependent altitude shift in OSIRIS measurements. In conjunction with the use of the time-dependent spectral point spread function, accounting for this altitude shift is shown to result in an almost complete elimination of the temperature-induced systematic errors seen in OSIRIS ozone profiles. Such improvements lead to improved ozone number density profiles for all times of the OSIRIS mission and make it possible to evaluate the use of different ozone cross sections as requested by the ACSO Commission.
413

A Hierarchical Analysis of Trial of Labour in Ontario: Do Women, Doctors or Hospitals Choose?

Wise, Michelle Rosanne 29 July 2010 (has links)
Background: Few studies have determined the contribution of maternity care provider and hospital factors to the variation in Trial of Labour (TOL) and successful TOL rates. Objective: To determine sources of variation in TOL and successful TOL rates at the provider and/or hospital level. Methods: Retrospective cohort study of 12,170 women with previous caesarean who gave birth in Ontario in 2007. Hierarchical linear model was used to determine variation in rates by provider and hospital characteristics, adjusting for maternal characteristics, and for clustering of data. Results: TOL rate was 23%; successful TOL rate 75%. Women attending family doctors and female doctors for prenatal care were more likely to have TOL. There were no provider factors associated with successful TOL. Women giving birth at teaching hospitals were more likely to have TOL and successful TOL. Conclusions: Policies aimed at prenatal care providers and hospitals could impact the low TOL rate.
414

Radar Target Modelling Based on RCS Measurements

Wessling, Andreas January 2002 (has links)
When simulating target seekers, there is a great need for computationally efficient, target models. This report considers a study of radar target modelling based on Inverse Synthetic Aperture Radar (ISAR) measurements of generic aircraft. The results underlie future modelling of full-size air targets. A method is developed for two-dimensional modelling of aspect-dependent target scattering. The approach taken is to generate point-scatterer models of two targets, where each point scatterer is defined according to its position and radar cross section (RCS), estimated from ISAR images. The scattered energy contributions from all point scatterers are summed to simulate a radar return signal. To validate the models, the modelled radar target centre is compared to the true radar target centre, which is determined from ISAR images. The method is presented to be promising for modelling air targets with large, persistent radar cross section.
415

A Hierarchical Analysis of Trial of Labour in Ontario: Do Women, Doctors or Hospitals Choose?

Wise, Michelle Rosanne 29 July 2010 (has links)
Background: Few studies have determined the contribution of maternity care provider and hospital factors to the variation in Trial of Labour (TOL) and successful TOL rates. Objective: To determine sources of variation in TOL and successful TOL rates at the provider and/or hospital level. Methods: Retrospective cohort study of 12,170 women with previous caesarean who gave birth in Ontario in 2007. Hierarchical linear model was used to determine variation in rates by provider and hospital characteristics, adjusting for maternal characteristics, and for clustering of data. Results: TOL rate was 23%; successful TOL rate 75%. Women attending family doctors and female doctors for prenatal care were more likely to have TOL. There were no provider factors associated with successful TOL. Women giving birth at teaching hospitals were more likely to have TOL and successful TOL. Conclusions: Policies aimed at prenatal care providers and hospitals could impact the low TOL rate.
416

Optimal Channel Design

Aksoy, Bulent 01 September 2003 (has links) (PDF)
The optimum values for the section variables like channel side slope,bottom width,depth and radius for triangular,rectangular, trapezoidal and circular channels are computed by minimizing the cost of the channel section.Manning &rsquo / s uniform flow formula is treated as a constraint for the optimization model.The cost function is arranged to include the cost of lining,cost of earthwork and the increment in the cost of earthwork with the depth below the ground surface.The optimum values of section variables are expressed as simple functions of unit cost terms.Unique values of optimum section variables are obtained for the case of minimum area or minimum wetted perimeter problems.
417

Optimal design of a flying-wing aircraft inner wing structure configuration

Huang, Haidong 01 1900 (has links)
Flying-wing aircraft are considered to have great advantages and potentials in aerodynamic performance and weight saving. However, they also have many challenges in design. One of the biggest challenges is the structural design of the inner wing (fuselage). Unlike the conventional fuselage of a tube configuration, the flying-wing aircraft inner wing cross section is limited to a noncircular shape, which is not structurally efficient to resist the internal pressure load. In order to solve this problem, a number of configurations have been proposed by other designers such as Multi Bubble Fuselage (MBF), Vaulted Ribbed Shell (VLRS), Flat Ribbed Shell (FRS), Vaulted Shell Honeycomb Core (VLHC), Flat Sandwich Shell Honeycomb Core (FLHC), Y Braced Box Fuselage and the modified fuselage designed with Y brace replaced by vaulted shell configurations. However all these configurations still inevitably have structural weight penalty compared with optimal tube fuselage layout. This current study intends to focus on finding an optimal configuration with minimum structural weight penalty for a flying-wing concept in a preliminary design stage. A new possible inner wing configuration, in terms of aerodynamic shape and structural layout, was proposed by the author, and it might be referred as ‘Wave-Section Configuration’. The methodologies of how to obtain a structurally efficient curvature of the shape, as well as how to conduct the initial sizing were incorporated. A theoretical analysis of load transmission indicated that the Wave-Section Configuration is feasible, and this was further proved as being practical by FE analysis. Moreover, initial FE analysis and comparison of the Wave-Section Configuration with two other typical configurations, Multi Bubble Fuselage and Conventional Wing, suggested that the Wave-Section Configuration is an optimal design in terms of weight saving. However, due to limitations of the author’s research area, influences on aerodynamic performances have not yet been taken into account.
418

The discord between policy and practice: defence lawyers’ use of section 718.2 (e) and Gladue

McDonald, Rana 13 September 2008 (has links)
This study explores the differences (and similarities) between sentencing reform and the legal practices of criminal defence lawyers. This research specifically focuses on Section 718.2 (e) of the Criminal Code, which is aimed at reducing the use of imprisonment for Aboriginal offenders and the application of the section in the Supreme Court’s 1999 decision R .v. Gladue. It investigates whether or not the section and/or Gladue has affected the legal practices of criminal defence lawyers and if so, how. The practice of lawyers, in this study, is conceptualized as structured action. The agency of lawyers is thus constrained and enabled by both macro and micro processes. These include traditional legal ideology, managerial/organizational ideology, presuppositions surrounding Aboriginality as well as the broader socio-political context of neo-liberalism and neo-conservativism. How the practices of defence lawyers either reflect or contradict the section and Gladue is examined through the oral narratives of lawyers—obtained through in-depth semi-structured interviews with twelve defence lawyers. The findings of this analysis show that the vast majority of lawyers were not integrating the section or Gladue in their defence strategies. This suggests that efforts to remedy the issue of Aboriginal over-incarceration need to be aware of the complexity of criminal justice processes, the agency of lawyers and the broader social and political context. / October 2008
419

Consistent energy treatment for radiation transport methods

Douglass, Steven James 30 March 2012 (has links)
A condensed multigroup formulation is developed which maintains direct consistency with the continuous energy or fine-group structure, exhibiting the accuracy of the detailed energy spectrum within the coarse-group calculation. Two methods are then developed which seek to invert the condensation process turning the standard one-way condensation (from fine-group to coarse-group) into the first step of a two-way iterative process. The first method is based on the previously published Generalized Energy Condensation, which established a framework for obtaining the fine-group flux by preserving the flux energy spectrum in orthogonal energy expansion functions, but did not maintain a consistent coarse-group formulation. It is demonstrated that with a consistent extension of the GEC, a cross section recondensation scheme can be used to correct for the spectral core environment error. A more practical and efficient new method is also developed, termed the "Subgroup Decomposition (SGD) Method," which eliminates the need for expansion functions altogether, and allows the fine-group flux to be decomposed from a consistent coarse-group flux with minimal additional computation or memory requirements. In addition, a new whole-core BWR benchmark problem is generated based on operating reactor parameters in 2D and 3D, and a set of 1D benchmark problems is developed for a BWR, PWR, and VHTR core.
420

Performance des jets et mesure de la section efficace de production de paires t tbar dans le canal tout hadronique auprès du détecteur ATLAS.

Ghodbane, N. 22 November 2012 (has links) (PDF)
Dans ce mémoire, nous présentons nos travaux de recherche que nous avons menés au sein de la collaboration ATLAS au LHC dans la période 2005-2012. Ces travaux inclus la préparation de deux des sous-détecteurs composant le système de détecteurs internes, l'étude et l'optimisation des algorithmes de reconstruction des jets afin d'en améliorer les performances et enfin l'utilisation des données collectées à partir des collisions proton-proton pour une énergie de collision de 7 TeV dans le centre de masse pour en extraire la mesure de la section efficace de production du quark top dans le mode de désintégration tout-hadronique.

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