Physical Sciences and Mathematics Commons™

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All Articles in Physical Sciences and Mathematics

74,932 full-text articles. Page 1 of 1218.

2016 Lehman College and Graduate Center of CUNY

Matrix Multiplication, Trilinear Decompositions, Apa Algorithms, And Summation, Victor Pan

Faculty Works

Matrix multiplication (hereafter we use the acronym MM) is among the most

fundamental operations of modern computations. The efficiency of its

performance depends on various factors, in particular vectorization, data

movement and arithmetic complexity of the computations, but here we focus

just on the study of the arithmetic cost and the impact of this study on

other areas of modern computing. In the early 1970s it was expected that

the straightforward cubic time algorithm for MM will soon be accelerated

to enable MM in nearly quadratic arithmetic time, with some far fetched

implications. While pursuing this goal the mainstream research ...

An Optimal Threshold Strategy In The Two-Envelope Problem With Partial Information, 2015 Universidad de la Republica Oriental del Uruguay

An Optimal Threshold Strategy In The Two-Envelope Problem With Partial Information, Martin Egozcue, Luis Fuentes García

Martin Egozcue

No abstract provided.

Castelnuovo–Mumford Regularity And Arithmetic Cohen–Macaulayness Of Complete Bipartite Subspace Arrangements, 2015 Boise State University

Castelnuovo–Mumford Regularity And Arithmetic Cohen–Macaulayness Of Complete Bipartite Subspace Arrangements, Zach Teitler, Douglas A. Torrence

Mathematics Faculty Publications and Presentations

We give the Castelnuovo–Mumford regularity of arrangements of (n−2)-planes in Pn whose incidence graph is a sufficiently large complete bipartite graph, and determine when such arrangements are arithmetically Cohen–Macaulay.

2015 University of Southern Mississippi

Gal: A Stepwise Model For Automated Cloud Shadow Detection In Hico Oceanic Imagery Utilizing Guided Filter, Pixel Assignment, And Geometric Linking, Jennerpher Renee Meyers

Dissertations

Detection of cloud shadow pixels is an important step in image processing in several remote sensing ocean-color application domains, such as obtaining chlorophyll content. While shadow detection algorithms do exist, the vast majority are for over land which leaves few options for detection over water.

The detection of cloud shadow over water in HICO imagery is a unique problem. As its name implies, HICO (Hyperspectral Imager for the Coastal Ocean) imagery is produced for coastal and oceanic regions. Since land based algorithms remove water before processing, these approaches would not be applicable. The only currently published HICO shadow pixel detection ...

2015 Northeastern University

Video Event Recognition And Prediction Based On Temporal Structure Analysis, Kang Li

Computer Engineering Dissertations

The increasing ubiquitousness of multimedia information in today's world has positioned video as a favored information vehicle, and given rise to an astonishing generation of social media and surveillance footage. Consumer-grade video is becoming abundant on the Internet, and it is now easier than ever to download multimedia material of any kind and quality. This raises a series of technological demands for automatic video understanding, which has motivated the research community to guide its steps towards a better attainment of such capabilities. As a result, current trends on cognitive vision promise to recognize complex events and self-adapt to different ...

2015 University of Texas at Dallas

A Right To Cyber Counter Strikes - The Risks Of Legalizing Hack Back, Jan Kallberg

Jan Kallberg

The idea to legalize hacking back has gained traction the last years and received several influential corporate and political proponents in the United States and Europe. The growing frustration with repeated cyberattacks and lack of credible law enforcement pushes for alternative ways to prevent future cyberattacks. As of today, counter cyberattacks are illegal in a majority of the nations because it constitutes another cybercrime independent from the initial attack. If cyber counter attacks were legalized it raises a set of questions. The first line of questions are linked to the underlying assumptions that the proposal to legalize counter cyberattacks are ...

2015 Lehman College and Graduate Center of CUNY

Random Multipliers Numerically Stabilize Gaussian And Block Gaussian Elimination: Proofs And An Extension To Low-Rank Approximation, Victor Pan, Xiaodong Yan

Faculty Works

We study two applications of standard Gaussian random multipliers. At first we prove that with a probability close to 1 such a multiplier is expected to numerically stabilize Gaussian elimination with no pivoting as well as block Gaussian elimination. Then, by extending our analysis, we prove that such a multiplier is also expected to support low-rank approximation of a matrix without customary oversampling. Our test results are in good accordance with this formal study. The results remain similar when we replace Gaussian multipliers with random circulant or Toeplitz multipliers, which involve fewer random parameters and enable faster multiplication. We formally ...

Dust Devils And Dustless Vortices On A Desert Playa Observed With Surface Pressure And Solar Flux Logging, 2015 Johns Hopkins University Applied Physics Laboratory

Dust Devils And Dustless Vortices On A Desert Playa Observed With Surface Pressure And Solar Flux Logging, Ralph D. Lorenz, Brian K. Jackson

Physics Faculty Publications and Presentations

Dust devils are convective vortices rendered visible by lofted dust, and may be a significant means of injecting dust into the atmosphere, on both Earth and Mars. The fraction of vortices that are dust-laden is not well-understood, however. Here we report a May/June 2013 survey on a Nevada desert playa using small stations that record pressure and solar flux with high time resolution (2 Hz): these data allow detection of vortices and an estimate of the dust opacity of the subset of vortices that geometrically occult the sun. The encounter rate of vortex pressure drops of 0.3 hPa ...

Validated Automatic Brain Extraction Of Head Ct Images, 2015 Johns Hopkins University

Validated Automatic Brain Extraction Of Head Ct Images, John Muschelli Iii, Natalie L. Ullman, Daniel F. Hanley, Paul Vespa, Ciprian M. Crainiceanu

John Muschelli III

Background

X-ray Computed Tomography (CT) imaging of the brain is commonly used in diagnostic settings. Al- though CT scans are primarily used in clinical practice, they are increasingly used in research. A fundamental processing step in brain imaging research is brain extraction – the process of separating the brain tissue from all other tissues. Methods for brain extraction have either been validated but not fully automated, or have been fully automated and informally proposed, but never formally validated.

Aim

To systematically analyze and validate the performance of FSL’s brain extraction tool (BET) on head CT images of patients with intracranial ...

Slides: Practicing Sustainability In Natural Resource Industries, 2015 University of Colorado Law School

Slides: Practicing Sustainability In Natural Resource Industries, Gary D. Libecap

Natural Resource Industries and the Sustainability Challenge (Martz Winter Symposium, February 27-28)

Presenter: Gary D. Libecap, Bren School of Environmental Science and Management and Economics Department, University of California, Santa Barbara, National Bureau of Economic Research (NBER)

10 slides

Tectono-Metamorphic History Of The Eastern Taureau Shear Zone, Mauricie Area, Québec: Implications For The Exhumation Of The Mid-Crust In The Grenville Province, 2015 Université du Québec à Montréal

Tectono-Metamorphic History Of The Eastern Taureau Shear Zone, Mauricie Area, Québec: Implications For The Exhumation Of The Mid-Crust In The Grenville Province, Renaud Soucy La Roche, Félix Gervais, Alain Tremblay, James L. Crowley, Gilles Ruffet

Geosciences Faculty Publications and Presentations

This study investigates the tectono-metamorphic history and exhumation mechanisms of the mid-crustal Mékinac-Taureau domain of the Mauricie area, central Grenville Province. Macro- and micro-structural analyses reveal the top-down-to-the-ESE sense of shear on the eastern Taureau shear zone, a major extensional structure that exhumed the mid-crustal Mékinac-Taureau domain and juxtaposed it against the lower grade rocks of the Shawinigan domain. Peak metamorphism in the Mékinac-Taureau domain, inferred to be the result of northwestward thrusting and regional crustal thickening, took place under PT conditions of 1000–1100 MPa and 820–880 °C prior to 1082 ± 20 Ma. Retrograde conditions varying from ...

Mapping Legume Roots Can Determine Best Performing Crops, 2015 Wilfrid Laurier University

Mapping Legume Roots Can Determine Best Performing Crops, Frédérique C. Guinel

Clear Language Summaries

Legume plants have a mutually beneficial relationship with bacteria. These beneficial bacteria live in nodules found on plant roots. Until recently there was no way to systematically measure the roots the nodules are found on and to place accurately the nodules on these roots. The research team created software and a method to measure multiple root parameters which were not available previously. This allows different plant varieties to be compared with precise measurements of the root structure in order to figure out which plants will grow better.

2015 Indiana University Maurer School of Law

Advantages Of A Polycentric Approach To Climate Change Policy, Daniel H. Cole

Faculty Publications

Lack of progress in global climate negotiations has led scholars to reconsider polycentric approaches to climate policy. Several examples of subglobal mechanisms to reduce greenhouse-gas emissions have been touted, but it remains unclear why they might achieve better climate outcomes than global negotiations alone. Decades of work conducted by researchers associated with the Vincent and Elinor Ostrom Workshop in Political Theory and Policy Analysis at Indiana University have emphasized two chief advantages of polycentric approaches over monocentric ones: they provide more opportunities for experimentation and learning to improve policies over time, and they increase communications and interactions — formal and informal ...

2015 Arizona State University

Negative Binomial Regerssion, 2nd Ed, 2nd Print, Errata And Comments, Joseph Hilbe

Joseph M Hilbe

Errata and Comments for 2nd printing of NBR2, 2nd edition. Previous errata from first printing all corrected. Some added and new text as well.

Torsion Free Biconformal Spaces: Reducing The Torsion Field Equations, 2015 Utah State University

Torsion Free Biconformal Spaces: Reducing The Torsion Field Equations, James Thomas Wheeler

James Thomas Wheeler

Our goal is to solve the full set of torsion and co-torsion field equations of Euclidean biconformal space, with only the assumption of vanishing torsion. Here we begin by resolving the involution constraints, symmetry conditions and torsion field equation into a single equation for further study.

2015 Washington University in St Louis

Grafalgo - A Library Of Graph Algorithms And Supporting Data Structures, Jonathan Turner

All Computer Science and Engineering Research

This report provides an overview of Grafalgo, an open-source library of graph algorithms and the data structures used to implement them. The programs in this library were originally written to support a graduate class in advanced data structures and algorithms at Washington University. Because the code's primary purpose was pedagogical, it was written to be as straightforward as possible, while still being highly efficient. Grafalgo is implemented in C++ and incorporates some features of C++11.

The library is available on an open-source basis and may be downloaded from https://code.google.com/p/grafalgo/. Source code documentation is ...

2015 Utah State University

Statistical Variation Of Diverse Light Emission Measurements From Bisphenol/Amine Epoxy Under Energetic Electron Bombardment, Justin Christensen

Physics Capstone Project

Dielectric materials subjected to energetic electron fluxes can emit light in several forms. We have observed three distinct types of emissions: (i) short-duration (<1 ms), high-intensity electrostatic discharge (ESD) or “arc” events; (ii) intermediate-duration, high-intensity events which begin with a bright arc followed by an exponential decay of intensity (~10 to 100 s decay constant), termed “flares”; and (iii) long-duration, low-intensity emission, or cathodoluminescence, that continues as long as the electron flux is on. These events were studied for bulk samples of bisphenol/amine epoxy, using an electron gun with varying current densities (0.3 to 5 nA/cm2) and energies (12 to 40 keV) in a high vacuum chamber. Light emitted from the samples was measured with a high-sensitivity visible to near-infrared video camera. Results of the spatial and temporal extent for each type of event are presented as well as a discussion of how absolute spectral radiance and rates for each type of event are dependent on incident electron current density, energy, and power density and on material type, temperature, and thickness. Applications of this research to spacecraft charging and light emissions are discussed.

Minimum Rank Of Graphs With Loops, 2015 Iowa State University

Minimum Rank Of Graphs With Loops, Chassidy Bozeman, Annavictoria Ellsworth, Leslie Hogben, Jephian Chin-Hung Lin, Gabi Maurer, Kathleen Nowak, Aaron Rodriguez, James Strickland

Electronic Journal of Linear Algebra

A loop graph $\mf G$ is a finite undirected graph that allows loops but does not allow multiple edges. The set $\sym(\lG)$ of real symmetric matrices associated with a loop graph $\lG$ of order $n$ is the set of symmetric matrices $A=[a_{ij}]\in\Rnn$ such that $a_{ij}\ne 0$ if and only if $ij\in E(\lG)$. The minimum (maximum) rank of a loop graph is the minimum (maximum) of the ranks of the matrices in $\sym(\lG)$. We characterize loop graphs having minimum rank at most two (by forbidden induced subgraphs and graph complements) and ...

Modeling Count Data; Errata And Comments, 2015 Arizona State University

Modeling Count Data; Errata And Comments, Joseph M. Hilbe

Joseph M Hilbe

Modeling Count Data: Errata and Comments PDF. Will be updated on a continuing basis.

A Comparative Study Of The Oxidation Characteristics Of Two Gasoline Fuels And An N-Heptane/Iso-Octane Surrogate Mixture, 2015 KAUST

A Comparative Study Of The Oxidation Characteristics Of Two Gasoline Fuels And An N-Heptane/Iso-Octane Surrogate Mixture, Tamour Javed, Ehson F. Nasir, Et-Touhami Es-Sebbar, Aamir Farooq

Dr. Et-touhami Es-sebbar

Ignition delay times and CO, H2O, OH and CO2 time-histories were measured behind reflected shock waves for two FACE (Fuels for Advanced Combustion Engines) gasolines and one PRF (Primary Reference Fuel) blend. The FACE gasolines chosen for this work are primarily paraffinic and have the same octane rating (∼RON = 84) as the PRF blend, but contain varying amounts of iso- and n-paraffins. Species time-histories and ignition delay times were measured using laser absorption methods over a temperature range of 1350–1550 K and pressures near 2 atm. Measured species time-histories and ignition delay times of the PRF blend and the ...