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Electronic Theses and Dissertations

2007

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Articles 91 - 104 of 104

Full-Text Articles in Physical Sciences and Mathematics

Towards A Self-Calibrating Video Camera Network For Content Analysis And Forensics, Imran Junejo Jan 2007

Towards A Self-Calibrating Video Camera Network For Content Analysis And Forensics, Imran Junejo

Electronic Theses and Dissertations

Due to growing security concerns, video surveillance and monitoring has received an immense attention from both federal agencies and private firms. The main concern is that a single camera, even if allowed to rotate or translate, is not sufficient to cover a large area for video surveillance. A more general solution with wide range of applications is to allow the deployed cameras to have a non-overlapping field of view (FoV) and to, if possible, allow these cameras to move freely in 3D space. This thesis addresses the issue of how cameras in such a network can be calibrated and how …

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Efficient Inversion Of The Cone Beam Transform For A General Class Of Curves, Mikhail Kapralov Jan 2007

Efficient Inversion Of The Cone Beam Transform For A General Class Of Curves, Mikhail Kapralov

Electronic Theses and Dissertations

We extend an efficient cone beam transform inversion formula, proposed earlier for helices, to a general class of curves. The conditions that describe the class are very natural. Curves C are smooth, without self-intersections, have positive curvature and torsion, do not bend too much in a certain sense, and do not admit lines which are tangent to C at one point and intersect C at another point. A domain U is found where reconstruction is possible with a filtered backprojection type algorithm. Results of numerical experiments demonstrate very good image quality. The algorithm developed is useful for image reconstruction in …

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Studies Of A Quantum Scheduling Algorithm And On Quantum Error Correction, Feng Lu Jan 2007

Studies Of A Quantum Scheduling Algorithm And On Quantum Error Correction, Feng Lu

Electronic Theses and Dissertations

Quantum computation has been a rich field of study for decades because it promises possible spectacular advances, some of which may run counter to our classically rooted intuitions. At the same time, quantum computation is still in its infancy in both theoretical and practical areas. Efficient quantum algorithms are very limited in number and scope; no real breakthrough has yet been achieved in physical implementations. Grover's search algorithm can be applied to a wide range of problems; even problems not generally regarded as searching problems can be reformulated to take advantage of quantum parallelism and entanglement leading to algorithms which …

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Far-Infrared/Millimeter Wave Source And Component Development For Imaging And Spectroscopy, Todd Du Bosq Jan 2007

Far-Infrared/Millimeter Wave Source And Component Development For Imaging And Spectroscopy, Todd Du Bosq

Electronic Theses and Dissertations

The far-infrared and millimeter wave (FIR/mmW) (wavelength 75 micrometer to 10 mm) portion of the electromagnetic spectrum is fairly underdeveloped technologically, owing to the large amount of atmospheric attenuation in that range. At present, the FIR/mmW region is lacking in compact, high-brightness radiation sources and practical imaging systems. This dissertation focuses on development of two complementary technologies in this area - an active mmW imaging system and high-reflectivity Bragg mirrors for the FIR p-Ge laser. The imaging system uses a vector network analyzer in the frequency range of 90-140 GHz as the radiation source and receiver. Raster scanning is used …

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Pade Approximants And One Of Its Applications, Tame-Kouontcho Fowe Jan 2007

Pade Approximants And One Of Its Applications, Tame-Kouontcho Fowe

Electronic Theses and Dissertations

This thesis is concerned with a brief summary of the theory of Pade approximants and one of its applications to Finance. Proofs of most of the theorems are omitted and many developments could not be mentioned due to the vastness of the field of Pade approximations. We provide reference to research papers and books that contain exhaustive treatment of the subject. This thesis is mainly divided into two parts. In the first part we derive a general expression of the Pade approximants and some of the results that will be related to the work on the second part of the …

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Developing Strand Space Based Models And Proving The Correctness Of The Ieee 802.11i Authentication Protocol With Restricted Sec, Zeeshan Furqan Jan 2007

Developing Strand Space Based Models And Proving The Correctness Of The Ieee 802.11i Authentication Protocol With Restricted Sec, Zeeshan Furqan

Electronic Theses and Dissertations

The security objectives enforce the security policy, which defines what is to be protected in a network environment. The violation of these security objectives induces security threats. We introduce an explicit notion of security objectives for a security protocol. This notion should precede the formal verification process. In the absence of such a notion, the security protocol may be proven correct despite the fact that it is not equipped to defend against all potential threats. In order to establish the correctness of security objectives, we present a formal model that provides basis for the formal verification of security protocols. We …

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Graph Theoretic Modeling: Case Studies In Redundant Arrays Of Independent Disks And Network Defense, Sanjeeb Nanda Jan 2007

Graph Theoretic Modeling: Case Studies In Redundant Arrays Of Independent Disks And Network Defense, Sanjeeb Nanda

Electronic Theses and Dissertations

Graph theoretic modeling has served as an invaluable tool for solving a variety of problems since its introduction in Euler's paper on the Bridges of Königsberg in 1736 . Two amongst them of contemporary interest are the modeling of Redundant Arrays of Inexpensive Disks (RAID), and the identification of network attacks. While the former is vital to the protection and uninterrupted availability of data, the latter is crucial to the integrity of systems comprising networks. Both are of practical importance due to the continuing growth of data and its demand at increasing numbers of geographically distributed locations through the use …

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High Birefringence Liquid Crystals For Optical Communications, Amanda Jane Parish Jan 2007

High Birefringence Liquid Crystals For Optical Communications, Amanda Jane Parish

Electronic Theses and Dissertations

High birefringence (Δn > 0.4) nematic liquid crystals are particularly attractive for infrared applications because they enable a thinner cell gap to be used for achieving fast response time and improved diffraction efficiency. In this thesis, the mesomorphic and electro‐optic properties of several new fluorinated isothiocyanate (NCS) terphenyl and phenyl tolane single compounds and mixtures are reported. The single compounds demonstrated Δn~0.35‐0.52 in the visible spectral region at room temperature and exhibit relatively low viscosity. It was found that lateral fluorine substitutions and short alkyl chains eliminate smectic phase and lower the melting temperature of the single compounds. However, the consequence …

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Forensic Analysis Of C-4 And Commercial Blasting Agents For Possible Discrimination, Katie Steele Jan 2007

Forensic Analysis Of C-4 And Commercial Blasting Agents For Possible Discrimination, Katie Steele

Electronic Theses and Dissertations

The criminal use of explosives has increased in recent years. Political instability and the wide spread access to the internet, filled with "homemade recipes," are two conjectures for the increase. C-4 is a plastic bonded explosive (PBX) comprised of 91% of the high explosive RDX, 1.6% processing oils, 5.3% plasticizer, and 2.1% polyisobutylene (PIB). C-4 is most commonly used for military purposes, but also has found use in commercial industry as well. Current methods for the forensic analysis of C-4 are limited to identification of the explosive; however, recent publications have suggested the plausibility of discrimination between C-4 samples based …

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Three-Dimensional Micron-Scale Metal Photonic Crystals Via Multi-Photon Direct Laser Writing And Electroless Metal Deposition, Amir Tal Jan 2007

Three-Dimensional Micron-Scale Metal Photonic Crystals Via Multi-Photon Direct Laser Writing And Electroless Metal Deposition, Amir Tal

Electronic Theses and Dissertations

Three-dimensional (3D) metal photonic crystals (MPCs) can exhibit interesting electromagnetic properties such as ultra-wide photonic or "plasmonic" band gaps, selectively tailored thermal emission, extrinsically modified absorption, and negative refractive index. Yet, optical-wavelength 3D MPCs remain relatively unexplored due to the challenges posed by their fabrication. This work explores the use of multi-photon direct laser writing (DLW) coupled with electroless metallization as a means for preparing MPCs. Multi-photon DLW was used to prepare polymeric photonic crystal (PC) templates having a targeted micron-scale structure and form. MPCs were then created by metallizing the polymeric PCs via wet-chemical electroless deposition. The electromagnetic properties …

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Stability And Preservation Properties Of Multisymplectic Integrators, Tomasz Wlodarczyk Jan 2007

Stability And Preservation Properties Of Multisymplectic Integrators, Tomasz Wlodarczyk

Electronic Theses and Dissertations

This dissertation presents results of the study on symplectic and multisymplectic numerical methods for solving linear and nonlinear Hamiltonian wave equations. The emphasis is put on the second order space and time discretizations of the linear wave, the Klein-Gordon and the sine-Gordon equations. For those equations we develop two multisymplectic (MS) integrators and compare their performance to other popular symplectic and non-symplectic numerical methods. Tools used in the linear analysis are related to the Fourier transform and consist of the dispersion relationship and the power spectrum of the numerical solution. Nonlinear analysis, in turn, is closely connected to the temporal …

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Methods For The Translocation Of The Yellow Lampmussel (Lampsilis Cariosa) And The Tidewater Mucket (Leptodea Ochracea) In The Fort Halifax Dam Impoundment Of The Sebasticok River, Maine, Jennifer Elaine Kurth Jan 2007

Methods For The Translocation Of The Yellow Lampmussel (Lampsilis Cariosa) And The Tidewater Mucket (Leptodea Ochracea) In The Fort Halifax Dam Impoundment Of The Sebasticok River, Maine, Jennifer Elaine Kurth

Electronic Theses and Dissertations

Translocation from areas where habitat alterations are proposed can be an important mussel conservation tool. Pending removal of the Fort Halifax dam on the Sebasticook River in Maine potentially would result in extensive mortality of two statelisted threatened species of mussels, yellow lampmussels (Lampsilis cariosa) and tidewater muckets (Leptodea ochracea), which occur in the impoundment above the dam. My study assessed populations of these two species in the impoundment, and determined the effects of within- and between-waterbody translocations on survival. I conducted a qualitative survey of the Fort Halifax dam impoundment in 2004 to determine locations …

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Effect Of Coyotes And Release Site Selection On Survival And Movement Of Translocated Swift Foxes In The Badlands Ecosystem Of South Dakota, Greg M. Schroeder Jan 2007

Effect Of Coyotes And Release Site Selection On Survival And Movement Of Translocated Swift Foxes In The Badlands Ecosystem Of South Dakota, Greg M. Schroeder

Electronic Theses and Dissertations

Success of different release strategies for swift fox (Vulpes velox) translocation was evaluated in the Badlands Ecosystem in southwestern South Dakota. Release site selection (outside coyote [Canis latrans] core-use areas compared to random release sites) and release method (i.e., hard, semi-hard, and soft) were examined to determine effects on swift fox survival and movements at 50 days post-release. I hypothesized that swift foxes released outside of coyote core-use areas would survive at a higher rate than foxes released at random sites. From 2003-2006, 16 adult coyotes were fitted with Global Positioning System (GPS) radio collars and monitored during the pup …

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Investigating Student Understanding Of Sound As A Longitudinal Wave, Earl C. Coombs Jan 2007

Investigating Student Understanding Of Sound As A Longitudinal Wave, Earl C. Coombs

Electronic Theses and Dissertations

The field of physics education research (PER) has highlighted the discrepancy between what is taught during traditional instruction in physics, and what students understand afterward. PER has also provided alternatives to traditional instruction that are research-based and have been shown to be more effective in bringing students’ level of understanding of physics more in line with that of the scientific community. One topic that has received attention is the propagation of sound. We confirmed that students in the introductory algebra-based and calculus-based physics courses at the University of Maine have difficulties with sound propagation similar to those documented by others. …

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