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Full-Text Articles in Physical Sciences and Mathematics

Law Library Blog (November 2020): Legal Beagle's Blog Archive, Roger Williams University School Of Law Nov 2020

Law Library Blog (November 2020): Legal Beagle's Blog Archive, Roger Williams University School Of Law

Law Library Newsletters/Blog

No abstract provided.


Lysenin Channels As Sensors For Ions And Molecules, Andrew Bogard, Gamid Abatchev, Zoe Hutchinson, Jason Ward, Pangaea W. Finn, Fulton Mckinney, Daniel Fologea Nov 2020

Lysenin Channels As Sensors For Ions And Molecules, Andrew Bogard, Gamid Abatchev, Zoe Hutchinson, Jason Ward, Pangaea W. Finn, Fulton Mckinney, Daniel Fologea

Physics Faculty Publications and Presentations

Lysenin is a pore-forming protein extracted from the earthworm Eisenia fetida, which inserts large conductance pores in artificial and natural lipid membranes containing sphingomyelin. Its cytolytic and hemolytic activity is rather indicative of a pore-forming toxin; however, lysenin channels present intricate regulatory features manifested as a reduction in conductance upon exposure to multivalent ions. Lysenin pores also present a large unobstructed channel, which enables the translocation of analytes, such as short DNA and peptide molecules, driven by electrochemical gradients. These important features of lysenin channels provide opportunities for using them as sensors for a large variety of applications. In …


Chemical Effects Of Cold Atmospheric Plasma On Food Nutrients, Juan Manuel Pérez Andrés Nov 2020

Chemical Effects Of Cold Atmospheric Plasma On Food Nutrients, Juan Manuel Pérez Andrés

Doctoral

A range of nonthermal techniques have demonstrated process efficacy in ensuring food product safety, extension of shelf-life and in general a retention of key quality attributes. However, various physical, chemical and biochemical effects of nonthermal techniques on both macro and micronutrients are evident, leading to both desirable and undesirable changes in food products. It is important to outline the effects of non-thermal techniques on food chemistry and the associated degradation mechanisms with the treatment of foods. Oxidation is one of the key mechanisms responsible for undesirable effects induced by non-thermal techniques. Degradation of key macromolecules largely depends on the processing …


A Database Of Ocean Primary Productivity From The 14c Method, J. F. Marra, R. T. Barber, (...), Walker O. Smith Jr., L. Zoffli Nov 2020

A Database Of Ocean Primary Productivity From The 14c Method, J. F. Marra, R. T. Barber, (...), Walker O. Smith Jr., L. Zoffli

VIMS Articles

The database on ocean primary productivity comprises over two decades (1985–2008) of data that the authors have participated in collecting, using the assimilation of inorganic 14C through photosynthesis, in incubations carried out in situ. The dataset is perhaps unique in that it uses, overwhelmingly, consistent methodology while covering a wide geographic range. Ancillary data are included. Using the database, it is hoped that investigators can test for the relationships among the environmental drivers for ocean productivity, the meaning of the 14C method in terms of phytoplankton physiology and the dynamics in the water column, and as a resource …


Stirring The Pot: Switching From Blended Fee-For-Service To Blended Capitation Models Of Physician Remuneration., Nibene H Somé, Rose Anne Devlin, Nirav Mehta, Gregory S Zaric, Sisira Sarma Nov 2020

Stirring The Pot: Switching From Blended Fee-For-Service To Blended Capitation Models Of Physician Remuneration., Nibene H Somé, Rose Anne Devlin, Nirav Mehta, Gregory S Zaric, Sisira Sarma

Epidemiology and Biostatistics Publications

In Canada's most populous province, Ontario, family physicians may choose between the blended fee-for-service (Family Health Group [FHG]) and blended capitation (Family Health Organization [FHO] payment models). Both models incentivize physicians to provide after-hours (AH) and comprehensive care, but FHO physicians receive a capitation payment per enrolled patient adjusted for age and sex, plus a reduced fee-for-service while FHG physicians are paid by fee-for-service. We develop a theoretical model of physician labor supply with multitasking to predict their behavior under FHG and FHO, and estimable equations are derived to test the predictions empirically. Using health administrative data from 2006 to …


Electromagnetic-Triboelectric-Hybrid Energy Tile For Biomechanical Green Energy Harvesting, Elaijah Islam, Abu Musa Abdullah, Aminur Rashid Chowdhury, Farzana Tasnim, Madelyne Martinez, Carolina Olivares, Karen Lozano, Mohammed Uddin Nov 2020

Electromagnetic-Triboelectric-Hybrid Energy Tile For Biomechanical Green Energy Harvesting, Elaijah Islam, Abu Musa Abdullah, Aminur Rashid Chowdhury, Farzana Tasnim, Madelyne Martinez, Carolina Olivares, Karen Lozano, Mohammed Uddin

Chemistry Faculty Publications and Presentations

Highlights

  • Hybrid nanogenerator based floor-tile was developed to convert the Bio-Mechanical energy of human footsteps to Electrical Energy.

  • Hybridization of Triboelectric Nanogenerator and Electro-Magnetic Generator consisting of Aluminum and Kapton.

  • MoS2 is working as an electron acceptor.

  • The maximum output is 1200V as open-circuit voltage, 5mA as short-circuit current, and 6W as power.

  • Produces 20% more power than a commercially sold energy-harvester floor tile.

Abstract

Since the invention of Piezoelectric Nanogenerator in 2006, nanogenerators has become an attractive technology to the researchers for scavenging mechanical energy from the ambient environment for real life applications. Hybridization of these nanogenerators has been …


Deepcommenter: A Deep Code Comment Generation Tool With Hybrid Lexical And Syntactical Information, Boao Li, Meng Yan, Xin Xia, Xing Hu, Ge Li, David Lo Nov 2020

Deepcommenter: A Deep Code Comment Generation Tool With Hybrid Lexical And Syntactical Information, Boao Li, Meng Yan, Xin Xia, Xing Hu, Ge Li, David Lo

Research Collection School Of Computing and Information Systems

As the scale of software projects increases, the code comments are more and more important for program comprehension. Unfortunately, many code comments are missing, mismatched or outdated due to tight development schedule or other reasons. Automatic code comment generation is of great help for developers to comprehend source code and reduce their workload. Thus, we propose a code comment generation tool (DeepCommenter) to generate descriptive comments for Java methods. DeepCommenter formulates the comment generation task as a machine translation problem and exploits a deep neural network that combines the lexical and structural information of Java methods. We implement DeepCommenter in …


Gwtc-2: Compact Binary Coalescences Observed By Ligo And Virgo During The First Half Of The Third Observing Run, R. Abbott, T. D. Abbott, Marco Cavaglia, For Full List Of Authors, Download The Pdf. Nov 2020

Gwtc-2: Compact Binary Coalescences Observed By Ligo And Virgo During The First Half Of The Third Observing Run, R. Abbott, T. D. Abbott, Marco Cavaglia, For Full List Of Authors, Download The Pdf.

Physics Faculty Research & Creative Works

We report on gravitational wave discoveries from compact binary coalescences detected by Advanced LIGO and Advanced Virgo between 1 April 2019 15:00 UTC and 1 October 2019 15:00 UTC. By imposing a false-alarm-rate threshold of two per year in each of the four search pipelines that constitute our search, we present 39 candidate gravitational wave events. At this threshold, we expect a contamination fraction of less than 10%. Of these, 26 candidate events were reported previously in near real-time through GCN Notices and Circulars; 13 are reported here for the first time. The catalog contains events whose sources are black …


The View From Ventress - 2019-20 Academic Year, University Of Mississippi, College Of Liberal Arts Nov 2020

The View From Ventress - 2019-20 Academic Year, University Of Mississippi, College Of Liberal Arts

Liberal Arts Newsletters

News from the College of Liberal Arts


Helmholtz Spacing Of Thin Rectangular Magnetic Field Coils, Karl J. Ahrendsen, Sarah Reyes, Timothy J. Gay Nov 2020

Helmholtz Spacing Of Thin Rectangular Magnetic Field Coils, Karl J. Ahrendsen, Sarah Reyes, Timothy J. Gay

Timothy J. Gay Publications

In this Note, we discuss the Helmholtz spacing for a pair of thin rectangular coils of arbitrary aspect ratio and consider how best to use such coils to compensate for Earth’s magnetic field along the coils’ Cartesian symmetry axes. Such coils are frequently used in conjunction with charged-particle beam machines. The Helmholtz spacing varies non-monotonically between that for square coils and that for four optimally spaced infinite wires. We consider other coil spacings that extend the length over which the field varies by less than some tolerance along the Cartesian symmetry axes. The calculations also provide a convenient means to …


Distinct Clinicopathologic Clusters Of Persons With Tdp-43 Proteinopathy, Yuriko Katsumata, Erin L. Abner, Shama Karanth, Merilee A. Teylan, Charles N. Mock, Matthew D. Cykowski, Edward B. Lee, Kevin L. Boehme, Shubhabrata Mukherjee, John S. K. Kauwe, Richard J. Kryscio, Frederick A. Schmitt, David W. Fardo, Peter T. Nelson Nov 2020

Distinct Clinicopathologic Clusters Of Persons With Tdp-43 Proteinopathy, Yuriko Katsumata, Erin L. Abner, Shama Karanth, Merilee A. Teylan, Charles N. Mock, Matthew D. Cykowski, Edward B. Lee, Kevin L. Boehme, Shubhabrata Mukherjee, John S. K. Kauwe, Richard J. Kryscio, Frederick A. Schmitt, David W. Fardo, Peter T. Nelson

Biostatistics Faculty Publications

To better understand clinical and neuropathological features of TDP-43 proteinopathies, data were analyzed from autopsied research volunteers who were followed in the National Alzheimer’s Coordinating Center (NACC) data set. All subjects (n = 495) had autopsy-proven TDP-43 proteinopathy as an inclusion criterion. Subjects underwent comprehensive longitudinal clinical evaluations yearly for 6.9 years before death on average. We tested whether an unsupervised clustering algorithm could detect coherent groups of TDP-43 immunopositive cases based on age at death and extensive neuropathologic data. Although many of the brains had mixed pathologies, four discernible clusters were identified. Key differentiating features were age at …


Literature Retrieval For Precision Medicine With Neural Matching And Faceted Summarization, Jiho Noh, Ramakanth Kavuluru Nov 2020

Literature Retrieval For Precision Medicine With Neural Matching And Faceted Summarization, Jiho Noh, Ramakanth Kavuluru

Institute for Biomedical Informatics Faculty Publications

Information retrieval (IR) for precision medicine (PM) often involves looking for multiple pieces of evidence that characterize a patient case. This typically includes at least the name of a condition and a genetic variation that applies to the patient. Other factors such as demographic attributes, comorbidities, and social determinants may also be pertinent. As such, the retrieval problem is often formulated as ad hoc search but with multiple facets (e.g., disease, mutation) that may need to be incorporated. In this paper, we present a document reranking approach that combines neural query-document matching and text summarization toward such retrieval scenarios. Our …


Oer Outdoor Ellipse Multicultural (Easter Island) Activity, Cynthia Huffman Ph.D. Nov 2020

Oer Outdoor Ellipse Multicultural (Easter Island) Activity, Cynthia Huffman Ph.D.

Faculty Submissions

This activity would fit in with a secondary or college algebra class studying conic sections, in particular ellipses, and gives students a multicultural hands-on application of the definition of an ellipse, while tracing out a full-scale model of the foundation of a hare paenga (boat house) from prehistoric Easter Island (Rapa Nui)..


Spotted Owls And Forest Fire: Comment, Gavin M. Jones, R. J. Gutiérrez, William M. Block, Peter C. Carlson, Emily J. Comfort, Samuel A. Cushman, Raymond J. Davis, Stephanie A. Eyes, Alan B. Franklin, Joseph L. Ganey, Shaula Hedwall, John J. Keane, Rodd Kelsey, Damon B, Lesmeister, Malcolm P. North, Susan L. Roberts, Jeremy T. Rockweit, Jamie S. Sanderlin, Sarah C. Sawyer, Ben Solvesky, Douglas J. Tempel, Ho Yi Wan, A. Leroy Westerling, Gary C. White, M. Zachariah Peery Nov 2020

Spotted Owls And Forest Fire: Comment, Gavin M. Jones, R. J. Gutiérrez, William M. Block, Peter C. Carlson, Emily J. Comfort, Samuel A. Cushman, Raymond J. Davis, Stephanie A. Eyes, Alan B. Franklin, Joseph L. Ganey, Shaula Hedwall, John J. Keane, Rodd Kelsey, Damon B, Lesmeister, Malcolm P. North, Susan L. Roberts, Jeremy T. Rockweit, Jamie S. Sanderlin, Sarah C. Sawyer, Ben Solvesky, Douglas J. Tempel, Ho Yi Wan, A. Leroy Westerling, Gary C. White, M. Zachariah Peery

United States Department of Agriculture Wildlife Services: Staff Publications

Western North American forest ecosystems are experiencing rapid changes in disturbance regimes because of climate change and land use legacies (Littell et al. 2018). In many of these forests, the accumulation of surface and ladder fuels from a century of fire suppression, coupled with a warming and drying climate, has led to increases in the number of large fires (Westerling 2016) and the proportion of areas burning at higher severity (Safford and Stevens 2017, Singleton et al. 2018). While the annual area burned by fire is still below historical levels (Taylor et al. 2016), some forest types in the west …


Seasonal Grassland Productivity Forecast For The U.S. Great Plains Using Grass-Cast, Melannie D. Hartman, William J. Parton, Justin D. Derner, Darin K. Schulte, William K. Smith, Dannele E. Peck, Ken A. Day, Stephen J. Del Grosso, Susan Lutz, Brian Fuchs, Maosi Chen, Wei Gao Nov 2020

Seasonal Grassland Productivity Forecast For The U.S. Great Plains Using Grass-Cast, Melannie D. Hartman, William J. Parton, Justin D. Derner, Darin K. Schulte, William K. Smith, Dannele E. Peck, Ken A. Day, Stephen J. Del Grosso, Susan Lutz, Brian Fuchs, Maosi Chen, Wei Gao

Drought Mitigation Center: Faculty Publications

Every spring, ranchers in the drought-prone U.S. Great Plains face the same difficult challenge —trying to estimate how much forage will be available for livestock to graze during the upcoming summer grazing season. To reduce this uncertainty in predicting forage availability, we developed an innovative new grassland productivity forecast system, named Grass-Cast, to provide science-informed estimates of growing season aboveground net primary production (ANPP). Grass-Cast uses over 30 yr of historical data including weather and the satellite-derived normalized vegetation difference index (NDVI)—combined with ecosystem modeling and seasonal precipitation forecasts—to predict if rangelands in individual counties are likely to produce below-normal, …


A Stable Version Of Harbourne's Conjecture And The Containment Problem For Space Monomial Curves, Eloísa Grifo Nov 2020

A Stable Version Of Harbourne's Conjecture And The Containment Problem For Space Monomial Curves, Eloísa Grifo

Department of Mathematics: Faculty Publications

The symbolic powers I(n) of a radical ideal I in a polynomial ring consist of the functions that vanish up to order n in the variety defined by I. These do not necessarily coincide with the ordinary algebraic powers In, but it is natural to compare the two notions. The containment problem consists of determining the values of n and m for which I(n)Im holds. When I is an ideal of height 2 in a regular ring, I(3)I2 may fail, but we …


Set Operation Aided Network For Action Units Detection, Huiyuan Yang, Taoyue Wang, Lijun Yin Nov 2020

Set Operation Aided Network For Action Units Detection, Huiyuan Yang, Taoyue Wang, Lijun Yin

Computer Science Faculty Research & Creative Works

As a large number of parameters exist in deep model-based methods, training such models usually requires many fully AU-annotated facial images. This is true with regard to the number of frames in two widely used datasets: BP4D [31] and DISFA [18], while those frames were captured from a small number of subjects (41, 27 respectively). This is problematic, as subjects produce highly consistent facial muscle movements, adding more frames per subject would only adds more close points in the feature space, and thus the classifier does not benefit from those extra frames. Data augmentation methods can be applied to alleviate …


Photodissociation Of Aqueous I 3 - Observed With Liquid-Phase Ultrafast Mega-Electron-Volt Electron Diffraction, K. Ledbetter, E. Biasin, J. P.F. Nunes, Martin Centurion, K. J. Gaffney, M. Kozina, M. F. Lin, X. Shen, J. Yang, X. J. Wang, T. J. A. Wolf, A. A. Cordones Nov 2020

Photodissociation Of Aqueous I 3 - Observed With Liquid-Phase Ultrafast Mega-Electron-Volt Electron Diffraction, K. Ledbetter, E. Biasin, J. P.F. Nunes, Martin Centurion, K. J. Gaffney, M. Kozina, M. F. Lin, X. Shen, J. Yang, X. J. Wang, T. J. A. Wolf, A. A. Cordones

Martin Centurion Publications

Developing femtosecond resolution methods for directly observing structural dynamics is critical to understanding complex photochemical reaction mechanisms in solution. We have used two recent developments, ultrafast mega-electron-volt electron sources and vacuum compatible sub-micron thick liquid sheet jets, to enable liquid-phase ultrafast electron diffraction (LUED). We have demonstrated the viability of LUED by investigating the photodissociation of tri-iodide initiated with a 400 nm laser pulse. This has enabled the average speed of the bond expansion to be measured during the first 750 fs of dissociation and the geminate recombination to be directly captured on the picosecond time scale.


Challenges To Select Suitable Habitats And Demonstrate ‘Additionality’ In Blue Carbon Projects: A Seagrass Case Study, Anna Lafratta, Oscar Serrano, Pere Masqué, Miguel A. Mateo, Milena Fernandes, Sam Gaylard, Paul S. Lavery Nov 2020

Challenges To Select Suitable Habitats And Demonstrate ‘Additionality’ In Blue Carbon Projects: A Seagrass Case Study, Anna Lafratta, Oscar Serrano, Pere Masqué, Miguel A. Mateo, Milena Fernandes, Sam Gaylard, Paul S. Lavery

Research outputs 2014 to 2021

© 2020 Elsevier Ltd Seagrass restoration has been suggested as a Blue Carbon (BC) strategy for climate change mitigation. For Nationally Determined Contributions (NDC) and carbon crediting schemes, BC projects need to demonstrate ‘additionality’, that is enhanced CO2 sequestration and/or avoided greenhouse gas emissions following management actions. This typically requires determining soil carbon accumulation rates (CAR), which is often done using radionuclides or surface elevation tables to estimate sedimentation rates. Here we undertook a case study, using 210Pb and 14C dating, to detect possible changes in Corg stocks and CAR following the loss and partial recovery of Posidonia seagrass meadows …


Seeing The Insurgent In Transformative Planning Practices, Efadul Huq Nov 2020

Seeing The Insurgent In Transformative Planning Practices, Efadul Huq

Environmental Science and Policy: Faculty Publications

Insurgent planning and radical planning are two of the most popular conceptual frames of reference for progressive planners and theorists of transformative planning practices. In the past decades, scholars have extended these two planning conceptions to new geographies and realities to shed light on how planning can challenge structural injustices and marginalization. However, less attention has been given to how insurgent planning renovates radical planning practices in response to the crisis of neoliberal urbanization. While appreciating that radical and insurgent planning remain braided in practice, this article contributes to the literature on transformative planning by highlighting how insurgent planning builds …


The Gauge Principle From The Schrodinger-Born Wave Mechanics, P. T. Leung Nov 2020

The Gauge Principle From The Schrodinger-Born Wave Mechanics, P. T. Leung

Physics Faculty Publications and Presentations

We propose an elementary way of introducing the gauge principle to beginners with a background in only mechanics, electromagnetism, and quantum mechanics. This evolves from an apparent conflict in the Schrodinger-Born formulation of wave mechanics, and does not have to resort to advanced concepts like covariant derivative and minimal coupling. With such an approach, one would have appreciated how interactions can be dictated from consideration of internal symmetry of a physical system, which serves as a principle underlying the foundation of almost all modern physics. In addition, the gauge principle also serves as a resource providing consistency between the Born …


Marine Wild-Capture Fisheries After Nuclear War, Kim J. N. Scherrer, Cheryl S. Harrison, Ryan F. Heneghan, Eric Galbraith, Charles G. Bardeen, Joshua Coupe, Jonas Jägermeyr, Nicole S. Lovenduski, August Luna, Alan Robock, Jessica Stevens, Samantha Stevenson, Owen B. Toon, Lili Xia Nov 2020

Marine Wild-Capture Fisheries After Nuclear War, Kim J. N. Scherrer, Cheryl S. Harrison, Ryan F. Heneghan, Eric Galbraith, Charles G. Bardeen, Joshua Coupe, Jonas Jägermeyr, Nicole S. Lovenduski, August Luna, Alan Robock, Jessica Stevens, Samantha Stevenson, Owen B. Toon, Lili Xia

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

Nuclear war, beyond its devastating direct impacts, is expected to cause global climatic perturbations through injections of soot into the upper atmosphere. Reduced temperature and sunlight could drive unprecedented reductions in agricultural production, endangering global food security. However, the effects of nuclear war on marine wild-capture fisheries, which significantly contribute to the global animal protein and micronutrient supply, remain unexplored. We simulate the climatic effects of six war scenarios on fish biomass and catch globally, using a state-of-the-art Earth system model and global process-based fisheries model. We also simulate how either rapidly increased fish demand (driven by food shortages) or …


College Of Natural Sciences Newsletter, November 2020, College Of Natural Sciences Nov 2020

College Of Natural Sciences Newsletter, November 2020, College Of Natural Sciences

College of Natural Sciences Newsletters and Reports

Volume 1. Issue 10

Content:

Dean’s Update P.1
Awards & Recognition P.2
Student Club Spotlight P.3
Open PRAIRIE | Interest in Science P.4
Bioethics Lecture P.5
External Advisory Board P.6
Science as Art Competition P.7


Diversity Patterns Associated With Varying Dispersal Capabilities As A Function Of Spatial And Local Environmental Variables In Small Wetlands In Forested Ecosystems, Brett M. Tornwall, Amber L. Pitt, Bryan L. Brown, Joanna Hawley-Howard, Robert F. Baldwin Nov 2020

Diversity Patterns Associated With Varying Dispersal Capabilities As A Function Of Spatial And Local Environmental Variables In Small Wetlands In Forested Ecosystems, Brett M. Tornwall, Amber L. Pitt, Bryan L. Brown, Joanna Hawley-Howard, Robert F. Baldwin

Faculty Scholarship

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. The diversity of species on a landscape is a function of the relative contribution of diversity at local sites and species turnover between sites. Diversity partitioning refers to the relative contributions of alpha (local) and beta (species turnover) diversity to gamma (regional/landscape) diversity and can be influenced by the relationship between dispersal capability as well as spatial and local environmental variables. Ecological theory predicts that variation in the distribution of organisms that are strong dispersers will be less influenced by spatial properties such as topography and connectivity of a region and …


Analyzing Yankees And Red Sox Sentiment Over The Course Of A Season, Connor Koch Nov 2020

Analyzing Yankees And Red Sox Sentiment Over The Course Of A Season, Connor Koch

Honors Projects in Data Science

This paper investigates data collected on twitter which references the Yankees or Red Sox during the 2020 Major League Baseball (MLB) season. The objective is to analyze the sentiment of tweets referencing the Yankees and Red Sox over the course of the season. In addition, an investigation of the networks within the data and the topics that were prevalent will be conducted. The 2020 MLB season was started late because of the COVID-19 pandemic and was a season like no other. The expectation of a dataset revolving around baseball is that the topics discussed would be about baseball. The findings …


The Impact Of Covid-19 On Asian Businesses And The Economy, Havovi Joshi Nov 2020

The Impact Of Covid-19 On Asian Businesses And The Economy, Havovi Joshi

Asian Management Insights

The Covid-19 pandemic will likely end when a vaccine can be made available to everyone, or when we have achieved some measure of herd immunity. Unfortunately, both are as yet nowhere in sight.


Oer Indoor Ellipse Multicultural (Easter Island) Activity, Cynthia Huffman Ph.D. Nov 2020

Oer Indoor Ellipse Multicultural (Easter Island) Activity, Cynthia Huffman Ph.D.

Faculty Submissions

This activity would fit in with a secondary or college algebra class studying conic sections, in particular ellipses, and gives students a multicultural hands-on application of the definition of an ellipse, while tracing out a scale model of the foundation of a hare paenga (boat house) from prehistoric Easter Island (Rapa Nui)..


Divide And Slide: Layer-Wise Refinement For Output Range Analysis Of Deep Neural Networks, Chao Huang, Jiameng Fan, Xin Chen, Wenchao Li, Qi Zhu Nov 2020

Divide And Slide: Layer-Wise Refinement For Output Range Analysis Of Deep Neural Networks, Chao Huang, Jiameng Fan, Xin Chen, Wenchao Li, Qi Zhu

Computer Science Faculty Publications

In this article, we present a layer-wise refinement method for neural network output range analysis. While approaches such as nonlinear programming (NLP) can directly model the high nonlinearity brought by neural networks in output range analysis, they are known to be difficult to solve in general. We propose to use a convex polygonal relaxation (overapproximation) of the activation functions to cope with the nonlinearity. This allows us to encode the relaxed problem into a mixed-integer linear program (MILP), and control the tightness of the relaxation by adjusting the number of segments in the polygon. Starting with a segment number of …


The Genetic Algorithm: Using Biology To Compute Liquid Crystal Director Configurations, Shouzhuo Yang , '23, Peter J. Collings Nov 2020

The Genetic Algorithm: Using Biology To Compute Liquid Crystal Director Configurations, Shouzhuo Yang , '23, Peter J. Collings

Physics & Astronomy Faculty Works

The genetic algorithm is an optimization routine for finding the solution to a problem that requires a function to be minimized. It accomplishes this by creating a population of solutions and then producing “offspring” solutions from this population by combining two “parental” solutions in much the way that the DNA of biological parents is combined in the DNA of offspring. Strengths of the algorithm include that it is simple to implement, no trial solution is required, and the results are fairly accurate. Weaknesses include its slow computational speed and its tendency to find a local minimum that does not represent …


Temperature-Dependent Phonon Lifetimes And Thermal Conductivity Of Silicon By Inelastic Neutron Scattering And Ab Initio Calculations, D. S. Kim, O. Hellman, N. Shulumba, C. N. Saunders, J. Y. Y. Lin, Hillary L. Smith, J. E. Herriman, J. L. Niedziela, D. L. Abernathy, C. W. Li, B. Fultz Nov 2020

Temperature-Dependent Phonon Lifetimes And Thermal Conductivity Of Silicon By Inelastic Neutron Scattering And Ab Initio Calculations, D. S. Kim, O. Hellman, N. Shulumba, C. N. Saunders, J. Y. Y. Lin, Hillary L. Smith, J. E. Herriman, J. L. Niedziela, D. L. Abernathy, C. W. Li, B. Fultz

Physics & Astronomy Faculty Works

Inelastic neutron scattering on a single crystal of silicon was performed at temperatures from 100 to 1500 K. These experimental data were reduced to obtain phonon spectral intensity at all wave vectors →Q and frequencies ω in the first Brillouin zone. Thermal broadenings of the phonon peaks were obtained by fitting and by calculating with an iterative ab initio method that uses thermal atom displacements on an ensemble of superlattices. Agreement between the calculated and experimental broadenings was good, with possible discrepancies at the highest temperatures. Distributions of phonon widths versus phonon energy had similar shapes for computation and experiment. …