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 Title
 Derivation of planar diffeomorphisms from Hamiltonians with a kick.
 Creator
 Barney, Zalmond C., Charles E. Schmidt College of Science, Department of Mathematical Sciences
 Abstract/Description

In this thesis we will discuss connections between Hamiltonian systems with a periodic kick and planar diffeomorphisms. After a brief overview of Hamiltonian theory we will focus, as an example, on derivations of the Hâenon map that can be obtained by considering kicked Hamiltonian systems. We will conclude with examples of Hâenon maps of interest.
 Date Issued
 2011
 PURL
 http://purl.flvc.org/FAU/3329833
 Subject Headings
 Mathematical physics, Differential equations, Partial, Hamiltonian systems, Algebra, Linear, Chaotic behavior in systems
 Format
 Document (PDF)
 Title
 Theoretical study of binary alloy thin film growth.
 Creator
 Bouwens, Mark R., Charles E. Schmidt College of Science, Department of Physics
 Abstract/Description

Computer simulations of the growth of binary alloy thin films in two and three dimensions were performed using an extension of the Solid on Solid model. Snapshots for a range of interactions and diffusion rates are presented and critically compared to experiment. A wide variety of distinct phases is identified and their growth conditions analyzed. These findings are summarized in a phase diagram. In addition, a fractal analysis of the domains is performed. It is found that for negative...
Show moreComputer simulations of the growth of binary alloy thin films in two and three dimensions were performed using an extension of the Solid on Solid model. Snapshots for a range of interactions and diffusion rates are presented and critically compared to experiment. A wide variety of distinct phases is identified and their growth conditions analyzed. These findings are summarized in a phase diagram. In addition, a fractal analysis of the domains is performed. It is found that for negative interactions the islands are twodimensional, while for positive interactions, regardless of diffusion rate, a fractal dimension of 1.78 is obtained.
Show less  Date Issued
 2011
 PURL
 http://purl.flvc.org/FAU/3174504
 Subject Headings
 Binary systems (Metallurgy), Mathematical models, Thermal diffusivity, Phase diagrams, Phase transformations (Statistical physics)
 Format
 Document (PDF)
 Title
 A study of divisors and algebras on a double cover of the affine plane.
 Creator
 Bulj, Djordje., Charles E. Schmidt College of Science, Department of Mathematical Sciences
 Abstract/Description

An algebraic surface defined by an equation of the form z2 = (x+a1y) ... (x + any) (x  1) is studied, from both an algebraic and geometric point of view. It is shown that the surface is rational and contains a singular point which is nonrational. The class group of Weil divisors is computed and the Brauer group of Azumaya algebras is studied. Viewing the surface as a cyclic cover of the affine plane, all of the terms in the cohomology sequence of Chase, Harrison and Roseberg are computed.
 Date Issued
 2012
 PURL
 http://purl.flvc.org/FAU/3355618
 Subject Headings
 Algebraic number theory, Geometry, Data processing, Noncommutative differential geometry, Mathematical physics, Curves, Algebraic, Commutative rings
 Format
 Document (PDF)
 Title
 Simulating the dynamic interaction of an AUV and towed magnetometer.
 Creator
 Miller, Lea Gabrielle., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

A magnetometer with a sensitivity of 0.01nT will be towed through the thermocline by a 2.87 meter long, 0.533 meter diameter autonomous underwater vehicle (AUV) to measure the magnetic fluctuations generated by oceanic internal waves. At this point, no research has been found that suggests towed magnetometer measurements have been done using an AUV. Simulations of the AUV, tow cable, and towfish are performed to provide an understanding of the effects of changing different input parameters,...
Show moreA magnetometer with a sensitivity of 0.01nT will be towed through the thermocline by a 2.87 meter long, 0.533 meter diameter autonomous underwater vehicle (AUV) to measure the magnetic fluctuations generated by oceanic internal waves. At this point, no research has been found that suggests towed magnetometer measurements have been done using an AUV. Simulations of the AUV, tow cable, and towfish are performed to provide an understanding of the effects of changing different input parameters, such as towing speed (0.52m/s), cable length (515m), vehicle trajectory (circle and vertical zig zag maneuvers), and current (0.251.25m/s). The AUVcabletowfish system and equations of motion needed for the simulations are described herein. Results show that a 5m tow cable provides better towfish maneuvering than the longer cable lengths. High towfish pitch angle is decreased by decreasing the distance between CG and CB. Surface currents speed of 0.25m/s change the AUV and towfish circle maneuver to a spiral trajectory, while 1.25m/s current speed cause a zig zag trajectory.
Show less  Date Issued
 2011
 PURL
 http://purl.flvc.org/FAU/3318670
 Subject Headings
 Automatic control, Mathematical models, Electromagnetic measurements, Fluctuations (Physics), Oceanographic submersibles, Computer simulation
 Format
 Document (PDF)
 Title
 Simulation study on option pricing under jump diffusion models.
 Creator
 Rodrigues, Justin, Long, Hongwei, Charles E. Schmidt College of Science, Department of Mathematical Sciences
 Abstract/Description

The main objective of this thesis is to simulate, evaluate and discuss several methods for pricing Europeanstyle options. The BlackScholes model has long been considered the standard method for pricing options. One of the downfalls of the BlackScholes model is that it is strictly continuous and does not incorporate discrete jumps. This thesis will consider two alternate Levy models that include discretized jumps; The Merton Jump Diffusion and Kou's Double Exponential Jump Diffusion. We...
Show moreThe main objective of this thesis is to simulate, evaluate and discuss several methods for pricing Europeanstyle options. The BlackScholes model has long been considered the standard method for pricing options. One of the downfalls of the BlackScholes model is that it is strictly continuous and does not incorporate discrete jumps. This thesis will consider two alternate Levy models that include discretized jumps; The Merton Jump Diffusion and Kou's Double Exponential Jump Diffusion. We will use each of the three models to price real world stock data through software simulations and explore the results.Keywords: Levy Processes, Brownian motion, Option pricing, Simulation, BlackScholes, Merton Jump Diffusion, Kou, Kou's Double Exponential Jump Diffusion.
Show less  Date Issued
 2013
 PURL
 http://purl.flvc.org/fau/fd/FA0004051
 Subject Headings
 Finance  Mathematical models, Levy processes, Prices  Econometric models, Statistical physics, Stochastic processes, Valuation  Econometric models
 Format
 Document (PDF)
 Title
 Simplicial matter in discrete and quantum spacetimes.
 Creator
 McDonald, Jonathan Ryan., Charles E. Schmidt College of Science, Department of Physics
 Abstract/Description

A discrete formalism for General Relativity was introduced in 1961 by Tulio Regge in the form of a piecewiselinear manifold as an approximation to (pseudo)Riemannian manifolds. This formalism, known as Regge Calculus, has primarily been used to study vacuum spacetimes as both an approximation for classical General Relativity and as a framework for quantum gravity. However, there has been no consistent effort to include arbitrary nongravitational sources into Regge Calculus or examine the...
Show moreA discrete formalism for General Relativity was introduced in 1961 by Tulio Regge in the form of a piecewiselinear manifold as an approximation to (pseudo)Riemannian manifolds. This formalism, known as Regge Calculus, has primarily been used to study vacuum spacetimes as both an approximation for classical General Relativity and as a framework for quantum gravity. However, there has been no consistent effort to include arbitrary nongravitational sources into Regge Calculus or examine the structural details of how this is done. This manuscript explores the underlying framework of Regge Calculus in an effort elucidate the structural properties of the lattice geometry most useful for incorporating particles and fields. Correspondingly, we first derive the contracted Bianchi identity as a guide towards understanding how particles and fields can be coupled to the lattice so as to automatically ensure conservation of source. In doing so, we derive a Kirchhofflike conservation principle that identifies the flow of energy and momentum as a flux through the circumcentric dual boundaries. This circuit construction arises naturally from the topological structure suggested by the contracted Bianchi identity. Using the results of the contracted Bianchi identity we explore the generic properties of the local topology in Regge Calculus for arbitrary triangulations and suggest a firstprinciples definition that is consistent with the inclusion of source. This prescription for extending vacuum Regge Calculus is sufficiently general to be applicable to other approaches to discrete quantum gravity. We discuss how these findings bear on a quantized theory of gravity in which the coupling to source provides a physical interpretation for the approximate invariance principles of the discrete theory.
Show less  Date Issued
 2009
 PURL
 http://purl.flvc.org/FAU/186691
 Subject Headings
 Special relativity (Physics), Space and time, Distribution (Probability theory), Global differential geometry, Quantum field theory, Mathematical physics
 Format
 Document (PDF)
 Title
 CFD Study of Pectoral Fins of Larval Zebrafish: Effect of Reynolds Number, Swimming Kinematics and Fin Bending on Fluid Structures and Transport.
 Creator
 Islam, Toukir, Curet, Oscar M., Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

Flow Structure and fluid transport via advection around pectoral fin of larval ZebraFish are studied numerically using Immersed Boundary Method, Lagrangian Coherent Structure, passive particle tracing, vortex core evolution and four statistically defined mixing numbers. Experimental fish kinematics for nominal swimming case are obtained from previous researchers and numerically manipulated to analyze the role of different body motion kinematics, Reynolds number and fin morphology on flow...
Show moreFlow Structure and fluid transport via advection around pectoral fin of larval ZebraFish are studied numerically using Immersed Boundary Method, Lagrangian Coherent Structure, passive particle tracing, vortex core evolution and four statistically defined mixing numbers. Experimental fish kinematics for nominal swimming case are obtained from previous researchers and numerically manipulated to analyze the role of different body motion kinematics, Reynolds number and fin morphology on flow structure and transport. Hyperbolic strain field and vortex cores are found to be effective particle transporter and their relative strength are driving force of varying flow structure and fluid transport. Translation and lateral undulation of fish; as a combination or individual entity, has coherent advantages and drawbacks significant enough to alter the nature of fluid advection. Reynolds number increase enhances overall fluid transport and mixing in varying order for different kinematics and nominal bending position of fin has average transport capability of other artificially induced fin morphology.
Show less  Date Issued
 2016
 PURL
 http://purl.flvc.org/fau/fd/FA00004606, http://purl.flvc.org/fau/fd/FA00004606
 Subject Headings
 Reynolds number., Aquatic animals (Physiology), Transport theory., Computational fluid dynamics., Dynamical systems., Continuum physics., TurbulenceMathematical models.
 Format
 Document (PDF)
 Title
 Empirical beam angle optimization for lung cancer intensity modulated radiation therapy.
 Creator
 Doozan, Brian, Pella, Silvia, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
 Abstract/Description

Empirical methods of beam angle optimization (BAO) are tested against the BAO that is currently employed in Eclipse treatment planning software. Creating an improved BAO can decrease the amount of time a dosimetrist spends on making a treatment plan, improve the treatment quality and enhance the tools an inexperienced dosimetrist can use to develop planning techniques. Using empirical data created by experienced dosimetrists from 69 patients treated for lung cancer, the most frequently used...
Show moreEmpirical methods of beam angle optimization (BAO) are tested against the BAO that is currently employed in Eclipse treatment planning software. Creating an improved BAO can decrease the amount of time a dosimetrist spends on making a treatment plan, improve the treatment quality and enhance the tools an inexperienced dosimetrist can use to develop planning techniques. Using empirical data created by experienced dosimetrists from 69 patients treated for lung cancer, the most frequently used gantry angles were applied to four different regions in each lung to gather an optimal set of fields that could be used to treat future lung cancer patients. This method, given the moniker FAU BAO, is compared in 7 plans created with the Eclipse BAO choosing 5 fields and 9 fields. The results show that the conformality index improved by 30% or 3% when using the 5 and 9 fields. The conformation number was better by 12% from the 5 fields and 9% from the 9 fields. The organs at risk (OAR) were overall more protected to produce fewer nonstochastic effects from the radiation treatment with the FAU BAO.
Show less  Date Issued
 2014
 PURL
 http://purl.flvc.org/fau/fd/FA00004280, http://purl.flvc.org/fau/fd/FA00004280
 Subject Headings
 Cancer  Radiotherapy, Image guided radiation therapy, Lung cancer  Treatment, Medical physics, Medical radiology  Data processing, Medicine  Mathematical models
 Format
 Document (PDF)
 Title
 Elliptic curves: identitybased signing and quantum arithmetic.
 Creator
 Budhathoki, Parshuram, Steinwandt, Rainer, Eisenbarth, Thomas, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Mathematical Sciences
 Abstract/Description

Pairingfriendly curves and elliptic curves with a trapdoor for the discrete logarithm problem are versatile tools in the design of cryptographic protocols. We show that curves having both properties enable a deterministic identitybased signing with “short” signatures in the random oracle model. At PKC 2003, Choon and Cheon proposed an identitybased signature scheme along with a provable security reduction. We propose a modification of their scheme with several performance benefits. In...
Show morePairingfriendly curves and elliptic curves with a trapdoor for the discrete logarithm problem are versatile tools in the design of cryptographic protocols. We show that curves having both properties enable a deterministic identitybased signing with “short” signatures in the random oracle model. At PKC 2003, Choon and Cheon proposed an identitybased signature scheme along with a provable security reduction. We propose a modification of their scheme with several performance benefits. In addition to faster signing, for batch signing the signature size can be reduced, and if multiple signatures for the same identity need to be verified, the verification can be accelerated. Neither the signing nor the verification algorithm rely on the availability of a (pseudo)random generator, and we give a provable security reduction in the random oracle model to the (`)Strong DiffieHellman problem. Implementing the group arithmetic is a costcritical task when designing quantum circuits for Shor’s algorithm to solve the discrete logarithm problem. We introduce a tool for the automatic generation of addition circuits for ordinary binary elliptic curves, a prominent platform group for digital signatures. Our Python software generates circuit descriptions that, without increasing the number of qubits or Tdepth, involve less than 39% of the number of Tgates in the best previous construction. The software also optimizes the (CNOT) depth for F2linear operations by means of suitable graph colorings.
Show less  Date Issued
 2014
 PURL
 http://purl.flvc.org/fau/fd/FA00004182, http://purl.flvc.org/fau/fd/FA00004182
 Subject Headings
 Coding theory, Computer network protocols, Computer networks  Security measures, Data encryption (Computer science), Mathematical physics, Number theory  Data processing
 Format
 Document (PDF)
 Title
 Statistics preserving spatial interpolation methods for missing precipitation data.
 Creator
 El Sharif, Husayn., College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
 Abstract/Description

Deterministic and stochastic weighting methods are commonly used methods for estimating missing precipitation rain gauge data based on values recorded at neighboring gauges. However, these spatial interpolation methods seldom check for their ability to preserve site and regional statistics. Such statistics and primarily defined by spatial correlations and other sitetosite statistics in a region. Preservation of site and regional statistics represents a means of assessing the validity of...
Show moreDeterministic and stochastic weighting methods are commonly used methods for estimating missing precipitation rain gauge data based on values recorded at neighboring gauges. However, these spatial interpolation methods seldom check for their ability to preserve site and regional statistics. Such statistics and primarily defined by spatial correlations and other sitetosite statistics in a region. Preservation of site and regional statistics represents a means of assessing the validity of missing precipitation estimates at a site. This study evaluates the efficacy of traditional interpolation methods for estimation of missing data in preserving site and regional statistics. New optimal spatial interpolation methods intended to preserve these statistics are also proposed and evaluated in this study. Rain gauge sites in the state of Kentucky are used as a case study, and several error and performance measures are used to evaluate the tradeoffs in accuracy of estimation and preservation of site and regional statistics.
Show less  Date Issued
 2012
 PURL
 http://purl.flvc.org/FAU/3355568
 Subject Headings
 Numerical analysis, Meteorology, Statistical methods, Spatial analysis (Statistics), Data processing, Atmospheric physics, Statistical methods, Geographic information systems, Mathematical models
 Format
 Document (PDF)
 Title
 Streamflow extremes and climate variability in Southeastern United States.
 Creator
 Bobsein, Jenna, Teegavarapu, Ramesh, Florida Atlantic University, College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
 Abstract/Description

Trends in streamflow extremes at a regional scale linked to the possible influences of four major oceanicatmospheric oscillations are analyzed in this study. Oscillations considered include: El Niño Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), Atlantic Multidecadal Oscillation (AMO), and North Atlantic Oscillation (NAO). The main emphasis is low flows in the SouthAtlantic Gulf region of the United States. Several standard drought indices of low flow extremes during two...
Show moreTrends in streamflow extremes at a regional scale linked to the possible influences of four major oceanicatmospheric oscillations are analyzed in this study. Oscillations considered include: El Niño Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), Atlantic Multidecadal Oscillation (AMO), and North Atlantic Oscillation (NAO). The main emphasis is low flows in the SouthAtlantic Gulf region of the United States. Several standard drought indices of low flow extremes during two different phases (warm/positive and cool/negative) of these oscillations are evaluated. Longterm streamflow data at 43 USGS sites in the region from the HydroClimatic Data Network that are least affected by anthropogenic influences are used for analysis. Results show that for ENSO, low flow indices were more likely to occur during La Niña phase; however, longer deficits were more likely during El Niño phase. Results also show that for PDO (AMO), all (most) low flow indices occur during the cool (warm) phase.
Show less  Date Issued
 2015
 PURL
 http://purl.flvc.org/fau/fd/FA00004348, http://purl.flvc.org/fau/fd/FA00004348
 Subject Headings
 Atmospheric physics  Statistical methods, Climate change mitigation, Climatic changes  Measurement, Hydrology, Mathematical statistics, Maxima and minima, Stream measurement
 Format
 Document (PDF)
 Title
 Sparse Modeling Applied to Patient Identification for Safety in Medical Physics Applications.
 Creator
 Lewkowitz, Stephanie, Kalantzis, Georgios, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
 Abstract/Description

Every scheduled treatment at a radiation therapy clinic involves a series of safety protocol to ensure the utmost patient care. Despite safety protocol, on a rare occasion an entirely preventable medical event, an accident, may occur. Delivering a treatment plan to the wrong patient is preventable, yet still is a clinically documented error. This research describes a computational method to identify patients with a novel machine learning technique to combat misadministration.The patient...
Show moreEvery scheduled treatment at a radiation therapy clinic involves a series of safety protocol to ensure the utmost patient care. Despite safety protocol, on a rare occasion an entirely preventable medical event, an accident, may occur. Delivering a treatment plan to the wrong patient is preventable, yet still is a clinically documented error. This research describes a computational method to identify patients with a novel machine learning technique to combat misadministration.The patient identification program stores face and fingerprint data for each patient. New, unlabeled data from those patients are categorized according to the library. The categorization of data by this facefingerprint detector is accomplished with new machine learning algorithms based on Sparse Modeling that have already begun transforming the foundation of Computer Vision. Previous patient recognition software required special subroutines for faces and di↵erent tailored subroutines for fingerprints. In this research, the same exact model is used for both fingerprints and faces, without any additional subroutines and even without adjusting the two hyperparameters. Sparse modeling is a powerful tool, already shown utility in the areas of superresolution, denoising, inpainting, demosaicing, and subnyquist sampling, i.e. compressed sensing. Sparse Modeling is possible because natural images are inherrently sparse in some bases, due to their inherrant structure. This research chooses datasets of face and fingerprint images to test the patient identification model. The model stores the images of each dataset as a basis (library). One image at a time is removed from the library, and is classified by a sparse code in terms of the remaining library. The Locally Competetive Algorithm, a truly neural inspired Artificial Neural Network, solves the computationally difficult task of finding the sparse code for the test image. The components of the sparse representation vector are summed by `1 pooling, and correct patient identification is consistently achieved 100% over 1000 trials, when either the face data or fingerprint data are implemented as a classification basis. The algorithm gets 100% classification when faces and fingerprints are concatenated into multimodal datasets. This suggests that 100% patient identification will be achievable in the clinal setting.
Show less  Date Issued
 2016
 PURL
 http://purl.flvc.org/fau/fd/FA00004721, http://purl.flvc.org/fau/fd/FA00004721
 Subject Headings
 Computer vision in medicine, Diagnostic imaging  Data processing, Mathematical models, Medical errors  Prevention, Medical physics, Sampling (Statistics)
 Format
 Document (PDF)
 Title
 A Computational Study on Different Penalty Approaches for Constrained Optimization in Radiation Therapy Treatment Planning with a Simulated Annealing Algorithm.
 Creator
 Mohammadi Khoroushadi, Mohammad Sadegh, Kalantzis, Georgios, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
 Abstract/Description

Intensity modulated radiation therapy (IMRT) is a cancer treatment method in which the intensities of the radiation beams are modulated; therefore these beams have nonuniform radiation intensities. The overall result is the delivery of the prescribed dose in the target volume. The dose distribution is conformal to the shape of the target and minimizes the dose to the nearby critical organs. An inverse planning algorithm is used to obtain those nonuniform beam intensities. In inverse...
Show moreIntensity modulated radiation therapy (IMRT) is a cancer treatment method in which the intensities of the radiation beams are modulated; therefore these beams have nonuniform radiation intensities. The overall result is the delivery of the prescribed dose in the target volume. The dose distribution is conformal to the shape of the target and minimizes the dose to the nearby critical organs. An inverse planning algorithm is used to obtain those nonuniform beam intensities. In inverse treatment planning, the treatment plan is achieved by using an optimization process. The optimized plan results to a highquality dose distribution in the planning target volume (PTV), which receives the prescribed dose while the dose that is received by the organs at risk (OARs) is reduced. Accordingly, an objective function has to be defined for the PTV, while some constraints have to be considered to handle the dose limitations for the OARs.
Show less  Date Issued
 2016
 PURL
 http://purl.flvc.org/fau/fd/FA00004765
 Subject Headings
 Imageguided radiation therapy., RadiationDosage., Mathematical optimization., Evolutionary programming (Computer science), Medical physics., Medical radiologyData processing.
 Format
 Document (PDF)
 Title
 How interpersonal coordination changes the self: Theory, experiment, and adaptive HKB model of social memory.
 Creator
 Nordham, Craig A, Kelso, J. A. Scott, Tognoli, Emmanuelle, Florida Atlantic University, Charles E. Schmidt College of Science, Center for Complex Systems and Brain Sciences
 Abstract/Description

How one behaves after interacting with a friend may not be the same as before the interaction began What factors a ect the formation of social interactions between people and, once formed, how do social interactions leave lasting changes on individual behavior? In this dissertation, a thorough review and conceptual synthesis is provided Major features of coordination dynamics are demonstrated with examples from both the intrapersonal and interpersonal coordination literature that are...
Show moreHow one behaves after interacting with a friend may not be the same as before the interaction began What factors a ect the formation of social interactions between people and, once formed, how do social interactions leave lasting changes on individual behavior? In this dissertation, a thorough review and conceptual synthesis is provided Major features of coordination dynamics are demonstrated with examples from both the intrapersonal and interpersonal coordination literature that are interpreted via a conceptual scheme, the causal loops of coordination dynamics An empirical, behavioral study of interpersonal coordination was conducted to determine which spontaneous patterns of coordination formed and whether a remnant of the interaction ensued ("social memory") To assess social memory in dyads, the behavior preceding and following episodes of interaction was compared In the experiment, pairs of people sat facing one another and made continuous flexionextension finger movements while a window acted as a shutter to control whether partners saw each other's movements Thus, vision ("social contact") allowed spontaneous information exchange between partners through observation Each trial consisted of three successive intervals lasting twenty seconds: without social contact ("me and you"), with social contact ("us"), and again without ("me and you") During social contact, a variety of patterns was observed ranging from phase coupling to transient or absent collective behavior Individuals also entered and exited social coordination differently In support of social memory, compared to before social contact, after contact ended participants tended to remain near each other's movement frequency Furthermore, the greater the stability of coupling, the more similar the partners' postinteractional frequencies were Proposing that the persistence of behavior in the absence of information exchange was the result of prior frequency adaptation, a mathematical model of human movement was implemented with HakenKelsoBunz oscillators that reproduced the experimental findings, even individual dyadic patterns Parametric manipulations revealed multiple routes to persistence of behavior via the interplay of adaptation and other HKB model parameters The experimental results, the model, and their interpretation form the basis of a proposal for future research and possible therapeutic applications
Show less  Date Issued
 2016
 PURL
 http://purl.flvc.org/fau/fd/FA00004793
 Subject Headings
 Ergodic theory, Dynamics, Conversation analysisSocial aspects, Social interaction, Social acceptance, Identity (Philosophical concept), Motivation (Psychology), Applied mathematics, Statistical physics
 Format
 Document (PDF)
 Title
 The Advantages of Collimator Optimization for Intensity Modulated Radiation Therapy.
 Creator
 Doozan, Brian, Leventouri, Theodora, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
 Abstract/Description

The goal of this study was to improve dosimetry for pelvic, lung, head and neck, and other cancers sites with aspherical planning target volumes (PTV) using a new algorithm for collimator optimization for intensity modulated radiation therapy (IMRT) that minimizes the xjaw gap (CAX) and the area of the jaws (CAA) for each treatment field. A retroactive study on the effects of collimator optimization of 20 patients was performed by comparing metric results for new collimator optimization...
Show moreThe goal of this study was to improve dosimetry for pelvic, lung, head and neck, and other cancers sites with aspherical planning target volumes (PTV) using a new algorithm for collimator optimization for intensity modulated radiation therapy (IMRT) that minimizes the xjaw gap (CAX) and the area of the jaws (CAA) for each treatment field. A retroactive study on the effects of collimator optimization of 20 patients was performed by comparing metric results for new collimator optimization techniques in Eclipse version 11.0. Keeping all other parameters equal, multiple plans are created using four collimator techniques: CA0, all fields have collimators set to 0°, CAE, using the Eclipse collimator optimization, CAA, minimizing the area of the jaws around the PTV, and CAX, minimizing the xjaw gap. The minimum area and the minimum xjaw angles are found by evaluating each field beam’s eye view of the PTV with ImageJ and finding the desired parameters with a custom script. The evaluation of the plans included the monitor units (MU), the maximum dose of the plan, the maximum dose to organs at risk (OAR), the conformity index (CI) and the number of fields that are calculated to split. Compared to the CA0 plans, the monitor units decreased on average by 6% for the CAX method with a pvalue of 0.01 from an ANOVA test. The average maximum dose remained within 1.1% difference between all four methods with the lowest given by CAX. The maximum dose to the most at risk organ was best spared by the CAA method, which decreased by 0.62% compared to the CA0. Minimizing the xjaws significantly reduced the number of split fields from 61 to 37. In every metric tested the CAX optimization produced comparable or superior results compared to the other three techniques. For aspherical PTVs, CAX on average reduced the number of split fields, lowered the maximum dose, minimized the dose to the surrounding OAR, and decreased the monitor units. This is achieved while maintaining the same control of the PTV.
Show less  Date Issued
 2017
 PURL
 http://purl.flvc.org/fau/fd/FA00004804, http://purl.flvc.org/fau/fd/FA00004804
 Subject Headings
 RadiationDosage., Optical engineering., Medical physics., Imageguided radiation therapy., CancerRadiotherapy., Medical radiologyData processing., MedicineMathematical models.
 Format
 Document (PDF)
 Title
 Subjecting the CHIMERA supernova code to two hydrodynamic test problems, (i) Riemann problem and (ii) Point blast explosion.
 Creator
 Ahsan, Abu Salah M., Charles E. Schmidt College of Science, Department of Physics
 Abstract/Description

A Shock wave as represented by the Riemann problem and a Pointblast explosion are two key phenomena involved in a supernova explosion. Any hydrocode used to simulate supernovae should be subjected to tests consisting of the Riemann problem and the Pointblast explosion. L. I. Sedov's solution of Pointblast explosion and Gary A. Sod's solution of a Riemann problem have been rederived here from one dimensional fluid dynamics equations . Both these problems have been solved by using the idea...
Show moreA Shock wave as represented by the Riemann problem and a Pointblast explosion are two key phenomena involved in a supernova explosion. Any hydrocode used to simulate supernovae should be subjected to tests consisting of the Riemann problem and the Pointblast explosion. L. I. Sedov's solution of Pointblast explosion and Gary A. Sod's solution of a Riemann problem have been rederived here from one dimensional fluid dynamics equations . Both these problems have been solved by using the idea of Selfsimilarity and Dimensional analysis. The main focus of my research was to subject the CHIMERA supernova code to these two hydrodynamic tests. Results of CHIMERA code for both the blast wave and Riemann problem have then been tested by comparing with the results of the analytic solution.
Show less  Date Issued
 2008
 PURL
 http://purl.flvc.org/FAU/172665
 Subject Headings
 Mathematical physics, Continuum mechanics, Number theory, Supernovae, Data processing, Shock waves, Fluid dynamics
 Format
 Document (PDF)