Tight-Binding Approximations in 1D and 2D Coupled-Cavity Photonic Crystal Structures

Light confinement and controlling an optical field has numerous applications in the field of telecommunications for optical signals processing. When the wavelength of the electromagnetic field is on the order of the period of a photonic microstructure, the field undergoes reflection, refraction, and coherent scattering. This produces photonic bandgaps, forbidden frequency regions or spectral stop bands where light cannot exist. Dielectric perturbations that break the perfect periodicity of these structures produce what is analogous to an impurity state in the bandgap of a semiconductor. The defect modes that exist at discrete frequencies within the photonic bandgap are spatially localized about the cavity-defects in the photonic crystal. In this thesis the properties of two tight-binding approximations (TBAs) are investigated in one-dimensional and two-dimensional coupled-cavity photonic crystal structures We require an efficient and simple approach that ensures the continuity of the electromagnetic field across dielectric interfaces in complex structures. In this thesis we develop \textrm{E} -- and \textrm{D} --TBAs to calculate the modes in finite 1D and 2D two-defect coupled-cavity photonic crystal structures. In the \textrm{E} -- and \textrm{D} --TBAs we expand the coupled-cavity \overrightarrow{E} --modes in terms of the individual \overrightarrow{E} -- and \overrightarrow{D} --modes, respectively. We investigate the dependence of the defect modes, their frequencies and quality factors on the relative placement of the defects in the photonic crystal structures. We then elucidate the differences between the two TBA formulations, and describe the conditions under which these formulations may be more robust when encountering a dielectric perturbation. Our 1D analysis showed that the 1D modes were sensitive to the structure geometry. The antisymmetric \textrm{D} mode amplitudes show that the \textrm{D} --TBA did not capture the correct (tangential \overrightarrow{E} --field) boundary conditions. However, the \textrm{D} --TBA did not yield significantly poorer results compared to the \textrm{E} --TBA. Our 2D analysis reveals that the \textrm{E} -- and \textrm{D} --TBAs produced nearly identical mode profiles for every structure. Plots of the relative difference between the \textrm{E} and \textrm{D} mode amplitudes show that the \textrm{D} --TBA did capture the correct (normal \overrightarrow{E} --field) boundary conditions. We found that the 2D TBA CC mode calculations were 125-150 times faster than an FDTD calculation for the same two-defect PCS. Notwithstanding this efficiency, the appropriateness of either TBA was found to depend on the geometry of the structure and the mode(s), i.e. whether or not the mode has a large normal or tangential component.

Restrictions on Aliens in the United Kingdom, 1914-1919 : a Study of the Origins and Political Background of the Aliens Restrictions Acts of 1914 and 1919.

At first glance the Aliens Restriction Act of 1914, which was introduced and passed on the first day of World War One, seems a hasty and ill-prepared piece of legislation. Actually, when examined in the light of Arthur Marwick's thesis that war is a forcing house for pre-existent social and governmental ideas, it becomes clear that the act was not after all the product of hastily formed notions. In point of fact it followed the precedent of detailed draft clauses produced in 1911 by a sub-committee of the Committee of Imperial Defence established to consider the treatment of aliens in the event of war. Indeed the draft clauses and the restrictions embodied in the 1914 act were strikingly similar to restrictions on aliens legislated in 1793. Hostility to aliens had been growing from 1905 to 1914 and this hostility blossomed into xeno-phobia on the outbreak of war, a crucial precondition for the specifically anti-enemy fears of the time. In 1919 the Aliens Restriction (Amendment) Bill was introduced into parliament to extend temporarily the provisions of the 1914 act thus permitting the Home Secretary to plan permanent, detailed legislation. Two minority groups of MPs with extreme views on the treatment of aliens were prominent in the debates on this bill. The extreme Liberal group which advocated leniency in the treatment of aliens had little effect on the final form of the bill, but the extreme Conservative group, which demanded severe restrictions on aliens, succeeded in persuading the government to include detailed restrictions. Despite its allegedly temporary nature, the Aliens Restriction (Amendment) Act of 1919 was renewed annually until 1971.

Terrain Controls and Landscape-Scale Susceptibility Modelling of Active-Layer Detachments, Sabine Peninsula, Melville Island, Nunavut

Modelling the susceptibility of permafrost slopes to disturbance can identify areas at risk to future disturbance and result in safer infrastructure and resource development in the Arctic. In this study, we use terrain attributes derived from a digital elevation model, an inventory of permafrost slope disturbances known as active-layer detachments (ALDs) and generalised additive modelling to produce a map of permafrost slope disturbance susceptibility for an area on northern Melville Island, in the Canadian High Arctic. By examining terrain variables and their relative importance, we identified factors important for initiating slope disturbance. The model was calibrated and validated using 70 and 30 per cent of a data-set of 760 mapped ALDs, including disturbed and randomised undisturbed samples. The generalised additive model calibrated and validated very well, with areas under the receiver operating characteristic curve of 0.89 and 0.81, respectively, demonstrating its effectiveness at predicting disturbed and undisturbed samples. ALDs were most likely to occur below the marine limit on slope angles between 3 and 10° and in areas with low values of potential incoming solar radiation (north-facing slopes).

Family Background and Access to Post-Secondary Education: What Happened in the 1990's (Woking Paper 34)

This paper presents new evidence on the relationships between access to post-secondary education and family background. More specifically, we use the School Leavers Survey (SLS) and the Youth in Transition Survey (YITS)to analyze participation rates first in 1991, and then almost a decade later in 2000. Overall, post-secondary education participation rates rose over this period. However, participation is strongly related to parent’s education, and whereas participation increased for individuals with more highly educated parents (especially those who went to university), they increased rather less, or in some cases (especially for males) declined for those from lower parental education families. The already strong “effect” of parents’ education on post-secondary access became even greater in the 1990’s. Participation rates are also strongly related to family type, but whereas those from two parent families continue to have an advantage over single mother families, the gap generally shrunk in the 1990’s, especially where the mother had university level schooling. We also find a number of interesting trends by province.

A Recursive Income Model for Canadians : The Direct and Indirect Effects of Family Background (Working Paper 28)

This paper presents the results of a multi-equation income model which has been estimated for Canadian men and women which incorporates the effects of a number of important family background variables, including mother’s and father’s education, parents’ immigration status, their age at immigration, place of birth, language development, and learning background. Not only education, but also the individual’s tested literacy and numeracy levels are treated as intermediate outcomes which are affected by background and which, in turn, affect income. Many of the background variables are found to have important indirect effects on income which would be missed by more conventional approaches. We also find some interesting gender aspects with respect to the influences of parents’ educations on their children’s outcomes. Various policy implications of the findings are discussed.

Towards Mapping of Rock Walls Using a UAV-Mounted 2D Laser Scanner in GPS Denied Environments

In geotechnical engineering, the stability of rock excavations and walls is estimated by using tools that include a map of the orientations of exposed rock faces. However, measuring these orientations by using conventional methods can be time consuming, sometimes dangerous, and is limited to regions of the exposed rock that are reachable by a human. This thesis introduces a 2D, simulated, quadcopter-based rock wall mapping algorithm for GPS denied environments such as underground mines or near high walls on surface. The proposed algorithm employs techniques from the field of robotics known as simultaneous localization and mapping (SLAM) and is a step towards 3D rock wall mapping. Not only are quadcopters agile, but they can hover. This is very useful for confined spaces such as underground or near rock walls. The quadcopter requires sensors to enable self localization and mapping in dark, confined and GPS denied environments. However, these sensors are limited by the quadcopter payload and power restrictions. Because of these restrictions, a light weight 2D laser scanner is proposed. As a first step towards a 3D mapping algorithm, this thesis proposes a simplified scenario in which a simulated 1D laser range finder and 2D IMU are mounted on a quadcopter that is moving on a plane. Because the 1D laser does not provide enough information to map the 2D world from a single measurement, many measurements are combined over the trajectory of the quadcopter. Least Squares Optimization (LSO) is used to optimize the estimated trajectory and rock face for all data collected over the length of a light. Simulation results show that the mapping algorithm developed is a good first step. It shows that by combining measurements over a trajectory, the scanned rock face can be estimated using a lower-dimensional range sensor. A swathing manoeuvre is introduced as a way to promote loop closures within a short time period, thus reducing accumulated error. Some suggestions on how to improve the algorithm are also provided.

The Most Complete Photometric Analysis of 548 CALIFA Galaxies

We present an extensive photometric catalog for 548 CALIFA galaxies observed as of the summer of 2015. CALIFA is currently lacking photometry matching the scale and diversity of its spectroscopy; this work is intended to meet all photometric needs for CALIFA galaxies while also identifying best photometric practices for upcoming integral field spectroscopy surveys such as SAMI and MaNGA. This catalog comprises gri surface brightness profiles derived from Sloan Digital Sky Survey (SDSS) imaging, a variety of non-parametric quantities extracted from these pro files, and parametric models fitted to the i-band pro files (1D) and original galaxy images (2D). To compliment our photometric analysis, we contrast the relative performance of our 1D and 2D modelling approaches. The ability of each measurement to characterize the global properties of galaxies is quantitatively assessed, in the context of constructing the tightest scaling relations. Where possible, we compare our photometry with existing photometrically or spectroscopically obtained measurements from the literature. Close agreement is found with Walcher et al. (2014), the current source of basic photometry and classifications of CALIFA galaxies, while comparisons with spectroscopically derived quantities reveals the effect of CALIFA's limited field of view compared to broadband imaging surveys such as the SDSS. The colour-magnitude diagram, star formation main sequence, and Tully-Fisher relation of CALIFA galaxies are studied, to give a small example of the investigations possible with this rich catalog. We conclude with a discussion of points of concern for ongoing integral field spectroscopy surveys and directions for future expansion and exploitation of this work.

Modeling the impact of large-scale solid mass transfers on the gravity field

The focus of this thesis is to explore and quantify the response of large-scale solid mass transfer events on satellite-based gravity observations. The gravity signature of large-scale solid mass transfers has not been deeply explored yet; mainly due to the lack of significant events during dedicated satellite gravity missions‘ lifespans. In light of the next generation of gravity missions, the feasibility of employing satellite gravity observations to detect submarine and surface mass transfers is of importance for geoscience (improves the understanding of geodynamic processes) and for geodesy (improves the understanding of the dynamic gravity field). The aim of this thesis is twofold and focuses on assessing the feasibility of using satellite gravity observations for detecting large-scale solid mass transfers and on modeling the impact on the gravity field caused by these events. A methodology that employs 3D forward modeling simulations and 2D wavelet multiresolution analysis is suggested to estimate the impact of solid mass transfers on satellite gravity observations. The gravity signature of various submarine and subaerial events that occurred in the past was estimated. Case studies were conducted to assess the sensitivity and resolvability required in order to observe gravity differences caused by solid mass transfers. Simulation studies were also employed in order to assess the expected contribution of the Next Generation of Gravity Missions for this application.

A Simple Model of Access and Capacity for Post-Secondary Schooling in Canada (Working Paper 40)

This paper develops a simple model of the post-secondary education system in Canada that provides a useful basis for thinking about issues of capacity and access. It uses a supply-demand framework, where demand comes on the part of individuals wanting places in the system, and supply is determined not only by various directives and agreements between educational ministries and institutions (and other factors), but also the money available to universities and colleges through tuition fees. The supply and demand curves are then put together with a stylised tuition-setting rule to describe the “market” of post-secondary schooling. This market determines the number of students in the system, and their characteristics, especially as they relate to “ability” and family background, the latter being especially relevant to access issues. The manner in which various changes in the system – including tuition fees, student financial aid, government support for institutions, and the returns to schooling – are then discussed in terms of how they affect the number of students and their characteristics, or capacity and access.

Paternalism and Competent Patient Choice in the Standards of Care for the Health of Transsexual, Transgender, and Gender-Nonconforming People

In 2016 physicians in Ontario will be granted the authority to refer patients with gender dysphoria for sex reassignment surgery. In order to be granted this authority physicians must be trained in the World Professional Association for Transgender Health’s Standards of Care, which outlines healthcare procedures for the treatment of gender dysphoria and provides background information concerning transgender health. The Standards of Care require that patients undergo a process of 12 months of continuous living in a gender role that is congruent with their gender identity prior to being given access to sex reassignment surgery. While this requirement can sometimes be helpful it can also cause more harm than benefit. This paper argues that the requirement is strongly paternalistic in its current form and should no longer be mandatory in most cases.