Iterative Matrix Factorization Method For Social Media Data Location Prediction, 2018 Harvey Mudd College

#### Iterative Matrix Factorization Method For Social Media Data Location Prediction, Natchanon Suaysom

*HMC Senior Theses*

Since some of the location of where the users posted their tweets collected by social media company have varied accuracy, and some are missing. We want to use those tweets with highest accuracy to help fill in the data of those tweets with incomplete information. To test our algorithm, we used the sets of social media data from a city, we separated them into training sets, where we know all the information, and the testing sets, where we intentionally pretend to not know the location. One prediction method that was used in (Dukler, Han and Wang, 2016) requires appending one-hot ...

Low-Communication, Parallel Multigrid Algorithms For Elliptic Partial Differential Equations, 2017 University of Colorado, Boulder

#### Low-Communication, Parallel Multigrid Algorithms For Elliptic Partial Differential Equations, Wayne Mitchell

*Applied Mathematics Graduate Theses & Dissertations*

When solving elliptic partial differential equations (PDE's) multigrid algorithms often provide optimal solvers and preconditioners capable of providing solutions with O(N) computational cost, where N is the number of unknowns. As parallelism of modern super computers continues to grow towards exascale, however, the cost of communication has overshadowed the cost of computation as the next major bottleneck for multigrid algorithms. Typically, multigrid algorithms require O((log P)^2) communication steps in order to solve a PDE problem to the level of discretization accuracy, where P is the number of processors. This has inspired the development of new algorithms ...

Parts Of The Whole: Why I Teach This Subject This Way, 2017 Dartmouth College

#### Parts Of The Whole: Why I Teach This Subject This Way, Dorothy Wallace

*Numeracy*

The importance of mathematics to biology is illustrated by search data from Google Scholar. I argue that a pedagogical approach based on student research projects is likely to improve retention and foster critical thinking about mathematical modeling, as well as reinforce quantitative reasoning and the appreciation of calculus as a tool. The usual features of a course (e.g., the instructor, assessment, text, etc.) are shown to have very different purposes in a research-based course.

Optimal Dual Fusion Frames For Probabilistic Erasures, 2017 Universidad Nacional de San Luis and CONICET, Argentina

#### Optimal Dual Fusion Frames For Probabilistic Erasures, Patricia Mariela Morillas

*Electronic Journal of Linear Algebra*

For any fixed fusion frame, its optimal dual fusion frames for reconstruction is studied in case of erasures of subspaces. It is considered that a probability distribution of erasure of subspaces is given and that a blind reconstruction procedure is used, where the erased data are set to zero. It is proved that there are always optimal duals. Sufficient conditions for the canonical dual fusion frame being either the unique optimal dual, a non-unique optimal dual, or a non optimal dual, are obtained. The reconstruction error is analyzed, using the optimal duals in the probability model considered here and using ...

Mathematical Description And Mechanistic Reasoning: A Pathway Toward Stem Integration, 2017 Oakland University

#### Mathematical Description And Mechanistic Reasoning: A Pathway Toward Stem Integration, Paul J. Weinberg

*Journal of Pre-College Engineering Education Research (J-PEER)*

Because reasoning about mechanism is critical to disciplined inquiry in science, technology, engineering, and mathematics (STEM) domains, this study focuses on ways to support the development of this form of reasoning. This study attends to how mechanistic reasoning is constituted through mathematical description. This study draws upon Smith’s (2007) characterization of mathematical description of scientific phenomena as ‘‘bootstrapping,’’ where negotiating the relationship between target phenomena and represented relations is fundamental to learning. In addition, the development of mathematical representation presents a viable pathway towards STEM integration. In this study, participants responded to an assessment of mechanistic reasoning while cognitive ...

Data Insertion In Bitcoin's Blockchain, 2017 Augustana College, Rock Island

#### Data Insertion In Bitcoin's Blockchain, Andrew Sward, Vecna Op_0, Forrest Stonedahl

*Computer Science: Faculty Scholarship & Creative Works*

This paper provides the first comprehensive survey of methods for inserting arbitrary data into Bitcoin's blockchain. Historical methods of data insertion are described, along with lesser-known techniques that are optimized for efficiency. Insertion methods are compared on the basis of efficiency, cost, convenience of data reconstruction, permanence, and potentially negative impact on the Bitcoin ecosystem.

An Investigation Of The Accuracy Of Parallel Analysis For Determining The Number Of Factors In A Factor Analysis, 2017 Western Kentucky University

#### An Investigation Of The Accuracy Of Parallel Analysis For Determining The Number Of Factors In A Factor Analysis, Mandy Matsumoto

*Honors College Capstone Experience/Thesis Projects*

Exploratory factor analysis is an analytic technique used to determine the number of factors in a set of data (usually items on a questionnaire) for which the factor structure has not been previously analyzed. Parallel analysis (PA) is a technique used to determine the number of factors in a factor analysis. There are a number of factors that affect the results of a PA: the choice of the eigenvalue percentile, the strength of the factor loadings, the number of variables, and the sample size of the study. Although PA is the most accurate method to date to determine which factors ...

Numerically Solving A System Of Pdes Modeling Chronic Wounds Treated With Oxygen Therapy, 2017 Western Kentucky University

#### Numerically Solving A System Of Pdes Modeling Chronic Wounds Treated With Oxygen Therapy, Stefan Stryker

*Honors College Capstone Experience/Thesis Projects*

Chronic wounds such as diabetic foot ulcers are the leading cause of non-traumatic amputations in developed countries. For researchers to better understand the physiology of these wounds, a mathematical model describing oxygen levels at the wound site can be used to help predict healing responses. The model utilizes equations that are modified from work by Guffey (2015) that consists of four variables – oxygen, bacteria, neutrophils, and chemoattractant within a system of partial differential equations. Our research focuses on numerically solving these partial differential equations using a finite volume approach. This numerical solver will be important for future research in optimization ...

Conference Program, 2017 University of Dayton

#### Conference Program, University Of Dayton

*Summer Conference on Topology and Its Applications*

Document provides a list of the sessions, speakers, workshops, and committees of the 32nd Summer Conference on Topology and Its Applications.

Catalytic Conversion Reactions In Nanoporous Systems With Concentration-Dependent Selectivity: Statistical Mechanical Modeling, 2017 Iowa State University

#### Catalytic Conversion Reactions In Nanoporous Systems With Concentration-Dependent Selectivity: Statistical Mechanical Modeling, Andrés García, Jing Wang, Theresa L. Windus, Aaron D. Sadow, James W. Evans

*Theresa Windus*

Statistical mechanical modeling is developed to describe a catalytic conversion reaction A→Bc or Bt with concentration-dependent selectivity of the products, Bc or Bt, where reaction occurs inside catalytic particles traversed by narrow linear nanopores. The associated restricted diffusive transport, which in the extreme case is described by single-file diffusion, naturally induces strong concentration gradients. Furthermore, by comparing kinetic Monte Carlo simulation results with analytic treatments, selectivity is shown to be impacted by strong spatial correlations induced by restricted diffusivity in the presence of reaction and also by a subtle clustering of reactants, A.

A Mathematical Model For Selective Differentiation Of Neural Progenitor Cells On Micropatterned Polymer Substrates, 2017 University of Iowa

#### A Mathematical Model For Selective Differentiation Of Neural Progenitor Cells On Micropatterned Polymer Substrates, Cory L. Howk, Howard A. Levine, Michael W. Smiley, Surya K. Mallapragada, Marit Nilsen-Hamilton, Jisun Oh, Donald S. Sakaguchi

*Surya K Mallapragada*

The biological hypothesis that the astrocyte-secreted cytokine, interleukin-6 (IL6), stimulates differentiation of adult rat hippocampal progenitor cells (AHPCs) is considered from a mathematical perspective. The proposed mathematical model includes two different mechanisms for stimulation and is based on mass–action kinetics. Both biological mechanisms involve sequential binding, with one pathway solely utilizing surface receptors while the other pathway also involves soluble receptors. Choosing biologically-reasonable values for parameters, simulations of the mathematical model show good agreement with experimental results. A global sensitivity analysis is also conducted to determine both the most influential and non-influential parameters on cellular differentiation, providing additional insights ...

Design Of Orbital Maneuvers With Aeroassisted Cubesatellites, 2017 University of Arkansas, Fayetteville

#### Design Of Orbital Maneuvers With Aeroassisted Cubesatellites, Stephanie Clark

*Stephanie Clark*

Recent advances within the field of cube satellite technology has allowed for the possible development of a maneuver that utilizes a satellite's Low Earth Orbit (LEO) and increased atmospheric density to effectively use lift and drag to implement a noncoplanar orbital maneuver. Noncoplanar maneuvers typically require large quantities of propellant due to the large delta-v that is required. However, similar maneuvers using perturbing forces require little or no propellant to create the delta-v required. This research reported here studied on the effects of lift on orbital changes, those of noncoplanar types in particular, for small satellites without orbital maneuvering ...

Modeling For Ut Inspection Of Anisotropic Materials, 2017 Iowa State University

#### Modeling For Ut Inspection Of Anisotropic Materials, Robert A. Roberts, Robert Grandin, Andrew Downs

*Robert Grandin*

This presentation reports on the extension of an established CNDE ultrasound beam transmission model to accommodate transmission in generally anisotropic materials. Using principles of elastodynamic reciprocity, the model expresses the internal wave field as a surface integral over the radiating transducer, employing the full Green function (point force response function) for the combined body under inspection and the coupling medium. The model evaluates the Green function asymptotically for short wavelength, and is therefore referred to as an asymptotic Green function model (AGF). The integrand of the transducer integral is projected on to a discretely orthogonal Gaussian basis, leading to a ...

A Management Maturity Model (Mmm) For Project-Based Organisational Performance Assessment, 2017 Bond University

#### A Management Maturity Model (Mmm) For Project-Based Organisational Performance Assessment, Craig Langston, Amir Ghanbaripour

*Amir Ghanbaripour*

Common sense suggests that organisations are more likely to deliver successful projects if they have systems in place that reflect a mature project environment based on a culture of continuous improvement. This paper develops and discusses a Management Maturity Model (MMM) to assess the maturity of project management organisations through a customisable, systematic, strategic and practical methodology inspired from the seminal work of Darwin, Deming, Drucker and Daniel. The model presented is relevant to organisations, such as construction and engineering companies, that prefer to use the Project Management Body of Knowledge (PMBOK™ Guide) published by the Project Management Institute (PMI ...

A Mathematical Model For Selective Differentiation Of Neural Progenitor Cells On Micropatterned Polymer Substrates, 2017 University of Iowa

#### A Mathematical Model For Selective Differentiation Of Neural Progenitor Cells On Micropatterned Polymer Substrates, Cory L. Howk, Howard A. Levine, Michael W. Smiley, Surya K. Mallapragada, Marit Nilsen-Hamilton, Jisun Oh, Donald S. Sakaguchi

*Marit Nilsen-Hamilton*

The biological hypothesis that the astrocyte-secreted cytokine, interleukin-6 (IL6), stimulates differentiation of adult rat hippocampal progenitor cells (AHPCs) is considered from a mathematical perspective. The proposed mathematical model includes two different mechanisms for stimulation and is based on mass–action kinetics. Both biological mechanisms involve sequential binding, with one pathway solely utilizing surface receptors while the other pathway also involves soluble receptors. Choosing biologically-reasonable values for parameters, simulations of the mathematical model show good agreement with experimental results. A global sensitivity analysis is also conducted to determine both the most influential and non-influential parameters on cellular differentiation, providing additional insights ...

Application Of Optimization Methods To Crack Profile Inversion Using Eddy Currents, 2017 Iowa State University

#### Application Of Optimization Methods To Crack Profile Inversion Using Eddy Currents, John R. Bowler, Wei Zhang, Aleksandar Dogandžić

*John R. Bowler*

A numerical scheme for finding crack shapes from eddy current measurements has been developed based on a startdard iterative inversion approach in which a nonlinear least squares objective function quantifying the overall difference between predictions and measurements is minimized. In this paper, steepest descent and conjugate‐gradient methods for minimizing the objective function are investigated and compared. Cramér‐Rao lower bounds on the crack parameters are derived to quantify the accuracy of the estimated crack shape. Cramér‐Rao bounds are also used to indicate improvements in the design of eddy‐current nondestructive evaluation systems.

Shrinkage Function And Its Applications In Matrix Approximation, 2017 University of Florida, Gainesville

#### Shrinkage Function And Its Applications In Matrix Approximation, Toby Boas, Aritra Dutta, Xin Li, Katie Mercier, Eric Niderman

*Electronic Journal of Linear Algebra*

The shrinkage function is widely used in matrix low-rank approximation, compressive sensing, and statistical estimation. In this article, an elementary derivation of the shrinkage function is given. In addition, applications of the shrinkage function are demonstrated in solving several well-known problems, together with a new result in matrix approximation.

Full Wave Modeling Of Ultrasonic Scattering Using Nystrom Method For Nde Applications, 2017 Iowa State University

#### Full Wave Modeling Of Ultrasonic Scattering Using Nystrom Method For Nde Applications, Praveen Gurrala, Kun Chen, Jiming Song, Ron Roberts

*Jiming Song*

Approximate methods for ultrasonic scattering like the Kirchhoff approximation and the geometrical theory of diffraction (GTD) can deliver fast solutions with relatively small computational resources compared to accurate numerical methods. However, these models are prone to inaccuracies in predicting scattered fields from defects that are not very large compared to wavelength. Furthermore, they do not take into account physical phenomena like multiple scattering and surface wave generation on defects. Numerical methods like the finite element method (FEM) and the boundary element method (BEM) can overcome these limitations of approximate models. Commercial softwares such as Abaqus FEA and PZFlex use FEM ...

Introduction To Classical Field Theory, 2017 Department of Physics, Utah State University

#### Introduction To Classical Field Theory, Charles G. Torre

*Charles G. Torre*

Catalytic Conversion Reactions In Nanoporous Systems With Concentration-Dependent Selectivity: Statistical Mechanical Modeling, 2017 Iowa State University

#### Catalytic Conversion Reactions In Nanoporous Systems With Concentration-Dependent Selectivity: Statistical Mechanical Modeling, Andrés García, Jing Wang, Theresa L. Windus, Aaron D. Sadow, James W. Evans

*James W. Evans*

Statistical mechanical modeling is developed to describe a catalytic conversion reaction A→Bc or Bt with concentration-dependent selectivity of the products, Bc or Bt, where reaction occurs inside catalytic particles traversed by narrow linear nanopores. The associated restricted diffusive transport, which in the extreme case is described by single-file diffusion, naturally induces strong concentration gradients. Furthermore, by comparing kinetic Monte Carlo simulation results with analytic treatments, selectivity is shown to be impacted by strong spatial correlations induced by restricted diffusivity in the presence of reaction and also by a subtle clustering of reactants, A.