Physical Sciences and Mathematics Commons^™

Robust Calibration Of Cameras With Telephoto Lens Using Regularized Least Squares, Mingpei Liang, Xinyu Huang, Chung-Hao Chen, Gaolin Zheng, Alade Tokuta

Electrical & Computer Engineering Faculty Publications

Cameras with telephoto lens are usually used to recover details of an object that is either small or located far away from the cameras. However, the calibration of this kind of cameras is not as accurate as the one of cameras with short focal lengths that are commonly used in many vision applications. This paper has two contributions. First, we present a first-order error analysis that shows the relation between focal length and estimation uncertainties of camera parameters. To our knowledge, this error analysis with respect to focal length has not been studied in the area of camera calibration. Second, …

An Itk Implementation Of A Physics-Based Non-Rigid Registration Method For Brain Deformation In Image Guided Neurosurgery, Yixun Liu, Andriy Kot, Fotis Drakopoulos, Chengjun Yao, Andriy Fedorov, Andinet Enquobahrie, Oliver Clatz, Nikos P. Chrisochoides

Electrical & Computer Engineering Faculty Publications

As part of the ITK v4 project efforts, we have developed ITK filters for physics-based non-rigid registration (PBNRR), which satisfies the following requirements: account for tissue properties in the registration, improve accuracy compared to rigid registration, and reduce execution time using GPU and multi-core accelerators. The implementation has three main components: (1) Feature Point Selection, (2) Block Matching (mapped to both multi-core and GPU processors), and (3) a Robust Finite Element Solver. The use of multi-core and GPU accelerators in ITK v4 provides substantial performance improvements. For example, for the non-rigid registration of brain MRIs, the performance of the block …

Stability Of High Band Gap P3ht: Pcbm Organic Solar Cells Using Tiox Interfacial Layer, Kurniawan Foe, Gon Namkoong, Matthew Samson, Enas M. Younes, Ilho Nam, Tarek M. Abdel-Fattah

Electrical & Computer Engineering Faculty Publications

We fabricated a poly [3-hexylthiophene] (P3HT) and [6,6] -phenyl-C61-butyric acid methyl ester (PC₆₁BM with the TiO_x layer. We found that a solution based TiO_x coated at a spin speed of 3000 rpm improved the photon absorption of the active layer. An optimized TiO_x layer was also used as the interfacial layer to investigate the stability of P3HT: PC₆₁BM OPC. After 70 days of storage, we observed that the short-circuit current density (J_SC) dropped by 16.2%, fill factor (FF) dropped by 10.6%, and power conversion efficiency (PCE) dropped approximately by 25%, while …

Weekly Gridded Aquarius L-Band Radiometer/Scatterometer Observations And Salinity Retrievals Over The Polar Regions - Part 1: Product Description, L. Brucker, Emmanuel P. Dinnat, L. S. Koenig

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Passive and active observations at L band (frequency similar to 1.4 GHz) from the Aquarius/SAC-D mission offer new capabilities to study the polar regions. Due to the lack of polar-gridded products, however, applications over the cryosphere have been limited. We present three weekly polar-gridded products of Aquarius data to improve our understanding of L-band observations of ice sheets, sea ice, permafrost, and the polar oceans. Additionally, these products intend to facilitate access to L-band data, and can be used to assist in algorithm developments. Aquarius data at latitudes higher than 50 degrees are averaged and gridded into weekly products of …

Zn(Ii) And Cu(Ii) Adsorption And Retention Onto Iron Oxyhydroxide Nanoparticles: Effects Of Particle Aggregation And Salinity, Rebecca B. Chesne, Christopher S. Kim

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Background: Iron oxyhydroxides are commonly found in natural aqueous systems as nanoscale particles, where they can act as effective sorbents for dissolved metals due to their natural surface reactivity, small size and high surface area. These properties make nanoscale iron oxyhydroxides a relevant option for the remediation of water supplies contaminated with dissolved metals. However, natural geochemical processes, such as changes in ionic strength, pH, and temperature, can cause these particles to aggregate, thus affecting their sorption capabilities and remediation potential. Other environmental parameters such as increasing salinity may also impact metal retention, e. g. when particles are transported …

Regional Dust Storm Modeling For Health Services: The Case Of Valley Fever, William A. Sprigg, Slobodan Nickovic, John N. Galgiani, Goran Pejanovic, Slavo Petkovic, Mirjam Vujadinovic, Ana Vukovic, Milan Dacic, Scott Dibiase, Anup K. Prasad, Hesham El-Askary

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

On 5 July 2011, a massive dust storm struck Phoenix, Arizona (USA), raising concerns for increased cases of valley fever (coccidioidomycosis, or, cocci). A quasi-operational experimental airborne dust forecast system predicted the event and provides model output for continuing analysis in collaboration with public health and air quality communities. An objective of this collaboration was to see if a signal in cases of valley fever in the region could be detected and traced to the storm - an American haboob. To better understand the atmospheric life cycle of cocci spores, the DREAM dust model (also herein, NMME-DREAM) was modified to …

Investigating The Biochemical And Catalytic Properties Of Nitrile Hydratases, Salette Martinez

Dissertations

Chemical and pharmaceutical industries make extensive use of amide compounds for the manufacture of commodity chemicals (e.g., acrylamide) and drug intermediates (e.g., nicotinamide). Production of amide compounds is typically achieved by the hydration of nitrile compounds under acidic or basic conditions, high temperatures, and copper catalysts. However, the use of such chemical methods leads to the generation of unwanted by-products and toxic wastes, in addition to low product yields and high production costs. An alternative route for amide production is the use of a natural catalyst, for example nitrile hydratases (NHase, E.C. 4.2.1.84). NHase is a metalloenzyme that efficiently converts …

Relative Equilibria Of Isosceles Triatomic Molecules In Classical Approximation, Damaris Miriam Mckinley

Theses and Dissertations (Comprehensive)

In this thesis we study relative equilibria of di-atomic and isosceles tri-atomic molecules in classical approximations with repulsive-attractive interaction. For di-atomic systems we retrieve well-known results. The main contribution consists of the study of the existence and stability of relative equilibria in a three-atom system formed by two identical atoms of mass $m$ and a third of mass $m_3$, constrained in an isosceles configuration at all times.

Given the shape of the binary potential only, we discuss the existence of equilibria and relative equilibria. We represent the results in the form of energy-momentum diagrams. We find that fixing the masses …

Synthesis And Characterization Of Coloumnar Mesophases Of Novel Substituted Dibenzanthracenes And Their Donor-Acceptor Mixtures, Katie M. Psutka

Theses and Dissertations (Comprehensive)

In this thesis, the synthesis and liquid crystalline properties of a series of novel dibenz[a,c]anthracenes are reported. Specifically, two dibenzanthracenecarboxylate derivatives were prepared and were found not to exhibit a mesophase. In contrast, a series of novel N-substituted dibenzanthracenedicarboximides was also synthesized and found to exhibit broad columnar temperature ranges. Several dibenzanthracenedicarboximides substituted with different alkyl chains on the nitrogen atom were prepared and their mesomorphic temperature ranges were characterized. In general, it was found that having a longer, more flexible alkyl chain on the nitrogen atom resulted in a broadening of the columnar temperature range via a lowering …

Surface Complexation Of Monosubstituted Organoarsenicals On Hematite: Atr-Ftir Investigations, Md Abdus Sabur

Theses and Dissertations (Comprehensive)

Little is known about the surface chemistry of organoarsenic compounds with iron-containing materials commonly found in geosorbents and arsenic removal technologies. In this thesis, these organoarsenicals include aliphatic and aromatic arsenicals that historically have been used as herbicides, pesticides and in the poultry feed industry, respectively. Attenuated total internal reflectance Fourier transform infrared spectroscopy has been used to study the surface interactions of organoarsenicals at the molecular level under various environmentally-relevant conditions. Kinetic and thermodynamic parameters extracted from these molecular level experiments provide trends that are not observed in any published bulk experiments. Apparent initial rates of adsorption and desorption …

A Computational Study Of Small Gold Clusters With H2s, Thiols, H2o, And Alcohols, Silvija C. Smith

Theses and Dissertations (Comprehensive)

Alkane thiols, RSH, are commonly used in aqueous solution to stabilize and prevent aggregation of gold clusters, Au_n. Initially a RSH-Au_n complex is formed and, subsequently, there is hydrogen atom transfer to form a RSAu_nH complex. We examine the rate of this reaction for small neutral gold clusters, with n=1-2 and short-chain thiols with R = H, CH₃, and CH₃CH₂, using transition state theory. The comparison of DFT (with the functionals, BP86 and M06-2X), and MP2 was performed. A pseudopotential was employed to account for the large relativisitic effects …

Quantifying Rooftop Solar Power For The City Of Waterloo, Ontario, Shawn W. Macdonald

Theses and Dissertations (Comprehensive)

Climate change, pollution, and energy security are driving a worldwide transition away from traditional fossil fuel generated electricity. As the world moves away from fossil fuels and towards renewable energy, electricity generated from photovoltaic solar panels is one of the most promising and capable technologies available today. Arguably the most suitable location to generate this electricity is at the source of consumption. Placing solar panels on unused rooftop space can subsidize the electricity demand that that building requires. This research quantifies the amount of electricity that can be generated within the City of Waterloo, Ontario. Using Natural Resources Canada data, …

Is Big Data Enough? A Reflection On The Changing Role Of Mathematics In Applications, Domenico Napoletani, Marco Panza, Daniele C. Struppa

Mathematics, Physics, and Computer Science Faculty Articles and Research

The advent of computers, and especially high-performance computers, has had a dramatic impact on the way in which mathematics is done and even more on how mathematics is applied, as demonstrated by the growth of computational mathematics as well as what goes under the name of “experimental mathematics”, to which a journal is now devoted. More importantly, computers are now used to perform highly complex computations in order to apply mathematical models to a variety of empirical problems that could never be attacked otherwise.

Foundations And Applications Of Weak Quantum Measurements, Yakir Aharonov, Eliahu Cohen, Avshalom C. Elitzur

Mathematics, Physics, and Computer Science Faculty Articles and Research

Weak quantum measurement (WM) is unique in measuring noncommuting operators and other peculiar, otherwise-undetectable phenomena predicted by the two-state-vector-formalism (TSVF). The aim of this article is threefold: (i) introducing the foundations of WM and TSVF, (ii) studying temporal peculiarities predicted by TSVF and manifested by WM, and (iii) presenting applications of WM to single particles.

Topological Duality And Lattice Expansions, I: A Topological Construction Of Canonical Extensions, M. Andrew Moshier, Peter Jipsen

Mathematics, Physics, and Computer Science Faculty Articles and Research

The two main objectives of this paper are (a) to prove purely topological duality theorems for semilattices and bounded lattices, and (b) to show that the topological duality from (a) provides a construction of canonical extensions of bounded lattices. In previously known dualities for semilattices and bounded lattices, the dual spaces are compact 0-dimensional spaces with additional algebraic structure. For example, semilattices are dual to 0-dimensional compact semilattices. Here we establish dual categories in which the spaces are characterized purely in topological terms, with no additional algebraic structure. Thus the results can be seen as generalizing Stone's duality for distributive …

On Free Stochastic Processes And Their Derivatives, Daniel Alpay, Palle Jorgensen, Guy Salomon

Mathematics, Physics, and Computer Science Faculty Articles and Research

We study a family of free stochastic processes whose covariance kernels K may be derived as a transform of a tempered measure σ. These processes arise, for example, in consideration non-commutative analysis involving free probability. Hence our use of semi-circle distributions, as opposed to Gaussians. In this setting we find an orthonormal bases in the corresponding noncommutative L2 of sample-space. We define a stochastic integral for our family of free processes.

Pt-Symmetric Acoustics, Xuefeng Zhu, Hamidreza Ramezani, Chengzhi Shi, Jie Zhu, Xiang Zhang

Physics and Astronomy Faculty Publications and Presentations

We introduce here the concept of acoustic parity-time (PT) symmetry and demonstrate the extraordinary scattering characteristics of the acoustic PT medium. On the basis of exact calculations, we show how an acoustic PT -symmetric medium can become unidirectionally transparent at given frequencies. Combining such a PT -symmetric medium with transformation acoustics, we design two-dimensional symmetric acoustic cloaks that are unidirectionally invisible in a prescribed direction. Our results open new possibilities for designing functional acoustic devices with directional responses.

Constraints On Cosmic Strings From The Ligo-Virgo Gravitational-Wave Detectors, Daniel Bessis, Teviet Creighton, H. Daveloza, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, Robert Stone, Lappoon R. Tang, Cristina V. Torres

Physics and Astronomy Faculty Publications and Presentations

Cosmic strings can give rise to a large variety of interesting astrophysical phenomena. Among them, powerful bursts of gravitational waves (GWs) produced by cusps are a promising observational signature. In this Letter we present a search for GWs from cosmic string cusps in data collected by the LIGO and Virgo gravitational wave detectors between 2005 and 2010, with over 625 days of live time. We find no evidence of GW signals from cosmic strings. From this result, we derive new constraints on cosmic string parameters, which complement and improve existing limits from previous searches for a stochastic background of GWs …

Auroral Ionospheric F Region Density Cavity Formation And Evolution: Mica Campaign Results, M. Zettergren, Kristina A. Lynch, D. Hampton, M. Nicolls, B. Wright, M. Conde, J. Moen, M. Lessard, R. Miceli, S. Powell

Dartmouth Scholarship

Auroral ionospheric F region density depletions observed by PFISR (Poker Flat Incoherent Scatter Radar) during the MICA (Magnetosphere-Ionosphere Coupling in the Alfvén Resonator) sounding rocket campaign are critically examined alongside complementary numerical simulations. Particular processes of interest include cavity formation due to intense frictional heating and Pedersen drifts, evolution in the presence of structured precipitation, and refilling due to impact ionization and downflows. Our analysis uses an ionospheric fluid model which solves conservation of mass, momentum, and energy equations for all major ionospheric species. These fluid equations are coupled to an electrostatic current continuity equation to self-consistently describe auroral electric …

Quantum Non-Locality Vs. Quasi-Local Measurement In The Conditions Of The Aharonov-Bohm Effect, Armen Gulian

Mathematics, Physics, and Computer Science Faculty Articles and Research

Theoretical explanation of the Meissner effect involves proportionality between current density and vector potential, which has many deep consequences. As noticed by de Gennes, superconductors in a magnetic field "find an equilibrium state where the sum of kinetic and magnetic energies is minimum" and this state "corresponds to the expulsion of the magnetic field". This statement still leaves an open question: from which source is the superconducting current acquiring its kinetic energy? A naïve answer, perhaps, is from the energy of the magnetic field. However, one can consider situations (Aharonov-Bohm effect), where the classical magnetic field is locally absent in …

Finite Element Spectral Approximation With Numerical Integration For The Biharmonic Eigenvalue Problem, Max Tran

Publications and Research

We investigate the convergence properties of a mixed finite element method approximation to the Biharmonic eigenvalue problem under the presence of numerical integration. We give a brief overview of the results obtained when exact integration is used in a finite element method, then develop related theories and obtained the convergence rates when numerical quadrature is taken into account. The standard approach to obtaining error estimate of variational eigenvalue problems is based on the error estimate of the solution operators of the source problems. The important issues are the rate of convergence of the solution operators and the conditions required for …

Terminal Summation: Extending The Concept Of Convergence, Max Tran, Ayalur Krishnan

Publications and Research

This paper presents an atypical method for summing divergent series, and provides a sum for the divergent series log(n). We use an idea of T.E. Phipps, called Terminal Summation, which uses asymptotic analysis to assign a value to divergent series. The method associates a series to an appropriate difference equations having boundary conditions at infinity, and solves the difference equations which then provide a value for the original series. We point out connections between Phipps' method, the Euler-MacLaurin sum formula, the Ramanujan sum and other traditional methods for summing divergent series.

Improving Pre-Hospital Care At Mass Gathering Events: Applying Military Intelligence Methodology To The St John Ambulance Wa Event Health Operations, Alan James Davies

Theses : Honours

With the growth of the mass gathering event domain and its ever constant place within the contemporary Australian lifestyle, the number of patrons who attend these events that require medical assistance rises (Zeitz et al., 2007, p. 23; Zeitz, Zeitz, & Arbon, 2005, p. 164; Zeitz, Zeitz, & Kadow-Griffin, 2012). This increased demand and inherited risk to the event organiser, the patrons attending and the pre-hospital care or first aid provider creates a need for the investigation into enhancements to the medical care operations at these events. The provision of pre-hospital care at mass gathering events in Western Australia is …

Search Queries In An Information Retrieval System For Arabic-Language Texts, Zainab Majeed Albujasim

Theses and Dissertations--Computer Science

Information retrieval aims to extract from a large collection of data a subset of information that is relevant to user’s needs. In this study, we are interested in information retrieval in Arabic-Language text documents. We focus on the Arabic language, its morphological features that potentially impact the implementation and performance of an information retrieval system and its unique characters that are absent in the Latin alphabet and require specialized approaches. Specifically, we report on the design, implementation and evaluation of the search functionality using the Vector Space Model with several weighting schemes. Our implementation uses the ISRI stemming algorithms as …

Influence Of Soil On Groundwater Geochemistry In A Carbonate Aquifer, Southern Italy, Tiziano Boschetti, Antonio Falasca, Antonio Bucci, Vincenzo De Felice, Gino Naclerio, Fulvio Celico

International Journal of Speleology

The role of soil compositions in influencing groundwater geochemistry in carbonate aquifers is still little known. Nothing is known regarding the influence of pyroclastic soils (andisol) within the carbonate Apennines in central-southern Italy, despite their wide distribution. In this study we analyze some physical and chemical properties of pyroclastic soil at the Acqua dei Faggi experimental site (southern Italy), to assess its influence on groundwater geochemistry. Chemical analyses were carried out on saturated paste extracts and a physical analogue model was developed through two column experiments. Physico-chemical properties of rainwater and spring water, and some microbiological features of the soil …

Study Of Filled Dolines By Using 3d Stereo Image Processing And Electrical Resistivity Imaging, Mateja Breg Valjavec

International Journal of Speleology

This article deals with doline degradation due to uncontrolled waste dumping in the past in the Logatec Polje in Slovenia. It introduces a concept for determining 3D geometric characteristics (shape, depth, radius, area, and volume) of formerly concave landforms (i.e., recently filled dolines) by using a combination of two methods: (1) photogrammetric stereo processing of archival aerial photographs and (2) electrical resistivity imaging (ERI). To represent, visualize, and study the characteristics of the former surface morphology (i.e., the dolines before they were filled), a digital terrain model (DTM) for 1972 (DTM1972) was made using digital photogrammetry processing of five sequential …

New Experiments In Gravitational Physics, Munawar Karim, Ashfaque H. Bokhari

Physics Faculty/Staff Publications

We propose experiments to examine and extend interpretations of the Einstein field equations. Experiments encompass the fields of astrophysics, quantum properties of the gravity field, gravitational effects on quantum electrodynamic phenomena and coupling of spinors to gravity. As an outcome of this work we were able to derive the temperature of the solar corona.

Embedded Star Formation In S4g Galaxy Dust Lanes., Debra M. Elmegreen, Bruce G. Elmegreen, Santiago Erroz-Ferrer, Johan H. Knapen, Yaron Teich, Mark Popinchalk, E. Athanassoula, Albert Bosma, Sebastien Comeron, Yuri N. Efremov, Dimitri A. Gadotti, Armando Gil De Paz, Joannah L. Hinz, Luis C. Ho, Benne W. Holwerda, Taehyun Kim, Jarkko Laine, Eija Laurikainen, Karin Menendez-Delmestre, Trisha Mizusawa, Juan Carlos Munoz-Mateos, Michael W. Regan, Heikki Salo, Mark Seibert, Kartik Sheth

Faculty and Staff Scholarship

Star-forming regions that are visible at 3.6 μm and Hα but not in the u, g, r, i, z bands of the Sloan Digital Sky Survey are measured in five nearby spiral galaxies to find extinctions averaging ∼3.8 mag and stellar masses averaging ∼5 × 104 M. These regions are apparently young star complexes embedded in dark filamentary shock fronts connected with spiral arms. The associated cloud masses are ∼107 M. The conditions required to make such complexes are explored, including gravitational instabilities in spiral-shocked gas and compression of incident clouds. We find that instabilities are too slow for a …

Ghosts I : A New Faint Very Isolated Dwarf Galaxy At D = 12 ± 2 Mpc., Antonela Monachesi, Eric F. Bell, David J. Radburn-Smith, Roelof S. De Jong, Jeremy Bailin, Julianne J. Dalcanton, Benne W. Holwerda, H. Alyson Ford, David Streich, Marija Vlajic, Daniel B. Zucker

Faculty and Staff Scholarship

We report the discovery of a new faint dwarf galaxy, GHOSTS I, using HST/ACS data from one of our GHOSTS (Galaxy Halos, Outer disks, Substructure, Thick disk, and Star clusters) fields. Its detected individual stars populate an approximately 1 mag range of its luminosity function (LF). Using synthetic color–magnitude diagrams (CMDs) to compare with the galaxy’s CMD, we find that the colors and magnitudes of GHOSTS I’s individual stars are most consistent with being young helium-burning and asymptotic giant branch stars at a distance of ∼12±2 Mpc. Morphologically, GHOSTS I appears to be actively forming stars, so we tentatively classify …

Constraining The Age Of The Ngc 4565 Hi Disk Warp : Determining The Origin Of Gas Warps., David J. Radburn-Smith, Roelof S. De Jong, David Streich, Eric F. Bell, Julianne J. Dalcanton, Andrew E. Dolphin, Adrienne M. Stilp, Antonela Monachesi, Benne W. Holwerda, Jeremy Bailin

Faculty and Staff Scholarship

We have mapped the distribution of young and old stars in the gaseous H i warp of NGC 4565. We find a clear correlation of young stars (< 600 Myr) with the warp but no coincident old stars (> 1 Gyr), which places an upper limit on the age of the structure. The formation rate of the young stars, which increased ∼ 300 Myr ago relative to the surrounding regions, is (6.3+2.5 −1.5) × 10−5 M yr−1 kpc−2. This implies a ∼ 60 ± 20 Gyr depletion time of the H i warp, similar to the timescales calculated for the outer H i disks of nearby spiral galaxies. While some stars …