Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

Publications

Discipline
Institution
Keyword
Publication Year
Publication Type
File Type

Articles 691 - 720 of 2389

Full-Text Articles in Entire DC Network

Large‐Amplitude Mountain Waves In The Mesosphere Observed On 21 June 2014 During Deepwave: 2. Nonlinear Dynamics, Wave Breaking, And Instabilities, David C. Fritts, Ling Wang, Michael J. Taylor, Pierre-Dominique Pautet, Neal R. Criddle, Bernd Kaifler, Stephen D. Eckermann, Ben Liley Aug 2019

Large‐Amplitude Mountain Waves In The Mesosphere Observed On 21 June 2014 During Deepwave: 2. Nonlinear Dynamics, Wave Breaking, And Instabilities, David C. Fritts, Ling Wang, Michael J. Taylor, Pierre-Dominique Pautet, Neal R. Criddle, Bernd Kaifler, Stephen D. Eckermann, Ben Liley

Publications

Weak cross‐mountain flow over the New Zealand South Island on 21 June 2014 during the Deep Propagating Gravity Wave Experiment (DEEPWAVE) led to large‐amplitude mountain waves in the mesosphere and lower thermosphere. The mesosphere and lower thermosphere responses were observed by ground‐based instruments in the lee of the Southern Alps supporting DEEPWAVE, including an Advanced Mesosphere Temperature Mapper, a Rayleigh lidar, an All‐Sky Imager, and a Fabry‐Perot Interferometer. The character of the mountain wave responses at horizontal scales of ~30–90 km reveals strong “sawtooth” variations in the temperature field suggesting large vertical and horizontal displacements leading to mountain wave overturning. …

Go to article

On-The-Road Testing Of The Effects Of Driver’S Experience, Gender, Speed, And Road Grade On Car Emissions, Abdelhaleem I. Khader, Randy S. Martin Aug 2019

On-The-Road Testing Of The Effects Of Driver’S Experience, Gender, Speed, And Road Grade On Car Emissions, Abdelhaleem I. Khader, Randy S. Martin

Publications

On-road vehicles have become a dominant source of air pollution and energy consumption in many parts of the world. As a result, estimating the amount of pollution from these vehicles and analyzing the factors affecting their emission is necessary to understand and manage ambient air quality. Traditionally, automobile emissions have been measured with dynamometer tests using representative driving cycles. A review of the related literature shows that there is a lack of real life, on-the-road testing of automobile emissions. Moreover, a few previous studies have directly discussed the impact of driver variability on emissions from the vehicles. This research analyzes …

Go to article

Seeing And Understanding Data, Beverly Wood, Charlotte Bolch Aug 2019

Seeing And Understanding Data, Beverly Wood, Charlotte Bolch

Publications

Visual displays of data are commonly used today in media reports online or in print. For example, data visualizations are sometimes used as a marketing tool to convince people to purchase a certain product, or they are displayed in articles or magazines as a way to graphically display data to emphasize a certain point. In general, it is hard to imagine the majority of disciplines in science and mathematics not using data visualizations. However, before standard data visualization techniques were developed (and accepted by the community), mathematicians and scientists very rarely used graphical displays or pictures to represent empirical data.

Go to article

Comparison Between Fluid Simulation With Test Particles And 1 Hybrid Simulation For The Kelvin-Helmholtz Instability, Xuanye Ma, Katariina Nykyri, Brandon L. Burkholder, Rachel C. Rice, Peter A. Delamere, Bishwa Neupane Aug 2019

Comparison Between Fluid Simulation With Test Particles And 1 Hybrid Simulation For The Kelvin-Helmholtz Instability, Xuanye Ma, Katariina Nykyri, Brandon L. Burkholder, Rachel C. Rice, Peter A. Delamere, Bishwa Neupane

Publications

A quantitative investigation of plasma transport rate via the Kelvin‐Helmholtz (KH) instability can improve our understanding of solar‐wind‐magnetosphere coupling processes. Simulation studies provide a broad range of transport rates by using different measurements based on different initial conditions and under different plasma descriptions, which makes cross literature comparison difficult. In this study, the KH instability under similar initial and boundary conditions (i.e., applicable to the Earth's magnetopause environment) is simulated by Hall magnetohydrodynamics with test particles and hybrid simulations. Both simulations give similar particle mixing rates. However, plasma is mainly transported through a few big magnetic islands caused by KH‐driven …

Go to article

Expanding Beyond Carnivores To Improve Livestock Protection And Conservation, Shari L. Rodriguez, Christie Sampson Aug 2019

Expanding Beyond Carnivores To Improve Livestock Protection And Conservation, Shari L. Rodriguez, Christie Sampson

Publications

Promoting human–wildlife coexistence is critical to the long-term conservation of many wild animal species that come into conflict with humans. Loss of livestock to carnivore species (e.g., lions, tigers, wolves) is a well-documented occurrence and the focus of mitigation strategies around the world. One area that has received little research is the impact of noncarnivores on livestock. Both African and Asian elephant species are known to cause livestock injuries and deaths. Livestock owners within elephant ranges perceive elephants as a risk to their livestock, which may reduce their tolerance towards elephants and jeopardize conservation efforts in the area. Though feral …

Go to article

Guest Editorial Special Issue On Toward Securing Internet Of Connected Vehicles (Iov) From Virtual Vehicle Hijacking, Yue Cao, Houbing Song, Omprakash Kaiwartya, Sinem Coleri Ergen, Jaime Lloret, Naveed Ahmad Aug 2019

Guest Editorial Special Issue On Toward Securing Internet Of Connected Vehicles (Iov) From Virtual Vehicle Hijacking, Yue Cao, Houbing Song, Omprakash Kaiwartya, Sinem Coleri Ergen, Jaime Lloret, Naveed Ahmad

Publications

Today’s vehicles are no longer stand-alone transportation means, due to the advancements on vehicle-tovehicle (V2V) and vehicle-to-infrastructure (V2I) communications enabled to access the Internet via recent technologies in mobile communications, including WiFi, Bluetooth, 4G, and even 5G networks. The Internet of vehicles was aimed toward sustainable developments in transportation by enhancing safety and efficiency. The sensor-enabled intelligent automation of vehicles’ mechanical operations enhances safety in on-road traveling, and cooperative traffic information sharing in vehicular networks improves traveling efficiency.

Go to article

Dynamic Identification Of Soil-Structure System Designed By Direct Displacement-Based Method For Different Site Conditions, Vahidreza Mahmoudabadi, Omid Bahar, Mohammad Kazem Jafari, Amir Safiey Aug 2019

Dynamic Identification Of Soil-Structure System Designed By Direct Displacement-Based Method For Different Site Conditions, Vahidreza Mahmoudabadi, Omid Bahar, Mohammad Kazem Jafari, Amir Safiey

Publications

This study mainly aims to assess the performance of soil-structure systems designed by direct displacement-based method coupled with strong column-weak beam design concept through various system identification techniques under strong ground motions. To this end, various system identification methods are employed to evaluate the dynamic characteristics of a structure (i.e., modal frequency, system damping, mode shapes, and plastic hinge formation pattern) under a strong seismic excitation considering soil-structure interaction for different site conditions as specified by ASCE 7-10. The scope of the study narrowed down to the code-complying low- to high-rise steel moment resisting frames with various heights (4, 8, …

Go to article

Strategies For Prioritizing Needs For Accelerated Construction After Hazard Events, Fernando Moreu, Chao Wang, Xinxing Yuan, Laleh Ghanbari, Claudia Garrido Aug 2019

Strategies For Prioritizing Needs For Accelerated Construction After Hazard Events, Fernando Moreu, Chao Wang, Xinxing Yuan, Laleh Ghanbari, Claudia Garrido

Publications

There is a need for rapid and responsive infrastructure repair and construction after natural disaster events such as hurricanes, wildfires, and tornadoes. These natural disasters often shut down basic infrastructure systems, as experienced recently in several Region 6 states as well as in other states around the country. Accelerated construction practices are often used in these situations to speed up the traditional, and often slow, project delivery process. However, after a natural disaster, several and different types of transportation infrastructure components are in need of inspection, rehabilitation or reconstruction, and transportation agencies are challenged with the task of prioritizing these …

Go to article

Ice Spiral Patterns On The Ocean Surface, Andrei Ludu, Zhi Zong Jul 2019

Ice Spiral Patterns On The Ocean Surface, Andrei Ludu, Zhi Zong

Publications

We investigate a new two-dimensional compressible Navier-Stokes hydrodynamic model design to explain and study large scale ice swirls formation at the surface of the ocean. The linearized model generates a basis of Bessel solutions from where various types of spiral patterns can be generated and their evolution and stability in time analyzed. By restricting the nonlinear system of equations to its quadratic terms we obtain swirl solutions emphasizing logarithmic spiral geometry. The resulting solutions are analyzed and validated using three mathematical approaches: one predicting the formation of patterns as Townes solitary modes, another approach mapping the nonlinear system into a …

Go to article

Design Of Personnel Big Data Management System Based On Blockchain, Houbing Song, Jian Chen, Zhihan Lv Jul 2019

Design Of Personnel Big Data Management System Based On Blockchain, Houbing Song, Jian Chen, Zhihan Lv

Publications

With the continuous development of information technology, enterprises, universities and governments are constantly stepping up the construction of electronic personnel information management system. The information of hundreds of thousands or even millions of people’s information are collected and stored into the system. So much information provides the cornerstone for the development of big data, if such data is tampered with or leaked, it will cause irreparable serious damage. However, in recent years, electronic archives have exposed a series of problems such as information leakage, information tampering, and information loss, which has made the reform of personnel information management more and …

Go to article

Adaboost‑Based Security Level Classifcation Of Mobile Intelligent Terminals, Feng Wang, Houbing Song, Dingde Jiang, Hong Wen Jul 2019

Adaboost‑Based Security Level Classifcation Of Mobile Intelligent Terminals, Feng Wang, Houbing Song, Dingde Jiang, Hong Wen

Publications

With the rapid development of Internet of Things, massive mobile intelligent terminals are ready to access edge servers for real-time data calculation and interaction. However, the risk of private data leakage follows simultaneously. As the administrator of all intelligent terminals in a region, the edge server needs to clarify the ability of the managed intelligent terminals to defend against malicious attacks. Therefore, the security level classification for mobile intelligent terminals before accessing the network is indispensable. In this paper, we firstly propose a safety assessment method to detect the weakness of mobile intelligent terminals. Secondly, we match the evaluation results …

Go to article

Regional Distribution Of Mesospheric Small‐Scale Gravity Waves During Deepwave, Pierre-Dominique Pautet, Michael J. Taylor, S. D. Eckermann, Neal R. Criddle Jul 2019

Regional Distribution Of Mesospheric Small‐Scale Gravity Waves During Deepwave, Pierre-Dominique Pautet, Michael J. Taylor, S. D. Eckermann, Neal R. Criddle

Publications

The Deep Propagating Gravity Wave Experiment project took place in June and July 2014 in New Zealand. Its overarching goal was to study gravity waves (GWs) as they propagate from the ground up to ~100 km, with a large number of ground‐based, airborne, and satellite instruments, combined with numerical forecast models. A suite of three mesospheric airglow imagers operated onboard the NSF Gulfstream V (GV) aircraft during 25 nighttime flights, recording the GW activity at OH altitude over a large region (>7,000,000 km2). Analysis of this data set reveals the distribution of the small‐scale GW mean power …

Go to article

Preservation Of Our Astronomical Heritage: State Of The Profession White Paper For Astro2020, James Lattis, Wayne Osborn, Terry D. Oswalt, Jennifer Lynn Bartlett, Elizabeth Griffin, Thomas Hockey, Stephen Mccluskey, Alexei A. Pevtsov, Sara Schechner, Virginia Trimble Jul 2019

Preservation Of Our Astronomical Heritage: State Of The Profession White Paper For Astro2020, James Lattis, Wayne Osborn, Terry D. Oswalt, Jennifer Lynn Bartlett, Elizabeth Griffin, Thomas Hockey, Stephen Mccluskey, Alexei A. Pevtsov, Sara Schechner, Virginia Trimble

Publications

We argue that it is essential that the Astro2020 survey of the present state of American astronomy and the recommendations for the next decade address the issue of ensuring preservation of, and making more discoverable and accessible, the field’s rich legacy materials. These include both archived observations of scientific value and items of historical importance. Much of this heritage likely will be lost if action is not taken in the next decade. It is proposed that the decadal plan include recommendations on (1) compiling a list of historic sites and development of models for their preservation, (2) carrying out a …

Go to article

Do My Students Know I Don't Like Writing? Shifting Attitudes And Instruction, Anna H. Hall Jul 2019

Do My Students Know I Don't Like Writing? Shifting Attitudes And Instruction, Anna H. Hall

Publications

The authors focus on how teachers’ attitudes toward writing can affect their instructional decisions. The authors give tips for teachers to self-reflect, explore avenues for mentoring and support, and develop and share with students their individual journey as a writer.

Go to article

Meshless Modeling Of Flow Dispersion And Progressive Piping In Poroelastic Levees, Anthony Khoury, Eduardo Divo, Alain J. Kassab, Sai Kakuturu, Lakshmi Reddi Jun 2019

Meshless Modeling Of Flow Dispersion And Progressive Piping In Poroelastic Levees, Anthony Khoury, Eduardo Divo, Alain J. Kassab, Sai Kakuturu, Lakshmi Reddi

Publications

Performance data on earth dams and levees continue to indicate that piping is one of the major causes of failure. Current criteria for prevention of piping in earth dams and levees have remained largely empirical. This paper aims at developing a mechanistic understanding of the conditions necessary to prevent piping and to enhance the likelihood of self-healing of cracks in levees subjected to hydrodynamic loading from astronomical and meteorological (including hurricane storm surge-induced) forces. Systematic experimental investigations are performed to evaluate erosion in finite-length cracks as a result of transient hydrodynamic loading. Here, a novel application of the localized collocation …

Go to article

Using More Frequent And Formative Assessment When Replicating The Wright State Model For Engineering Mathematics Education, Leroy Long Iii, Claudia Morello Jun 2019

Using More Frequent And Formative Assessment When Replicating The Wright State Model For Engineering Mathematics Education, Leroy Long Iii, Claudia Morello

Publications

A mid-sized private university in the Southeast has created an experimental first-year engineering course based on the Wright State Model for Engineering Mathematics Education. The course aims to increase student retention, motivation and success in engineering through an application-oriented, hands-on introduction to engineering mathematics. When compared to the traditional Wright State Model for Engineering Mathematics Education, the new course also focused on student communication (written, oral), teamwork, self-regulated learning and professionalism. The new experimental course also uses more frequent and formative assessment techniques. Faculty used Wright State’s sample homework assignments to provide students’ with formative feedback and Wright State’s sample …

Go to article

Parameterizing Wave‐Driven Vertical Constituent Transport In The Upper Atmosphere, Alan Z. Liu, Chester S. Gardner, Yafang Guo Jun 2019

Parameterizing Wave‐Driven Vertical Constituent Transport In The Upper Atmosphere, Alan Z. Liu, Chester S. Gardner, Yafang Guo

Publications

Dissipating waves contribute to vertical mixing of the atmosphere, alter molecular and eddy diffusion, and induce chemical transport of reactive species. These processes induce strong vertical transport of atmospheric constituents in regions where wave dissipation is significant. The effective wave diffusivity is proportional to the Stokes drift velocity imparted by the spectrum of vertically propagating waves, which is related to the vertical heat and wave energy fluxes. Because the heat flux cannot be derived from wave parameterization schemes employed in most atmospheric models, wave‐driven constituent transport has not been fully incorporated. However, we show in this paper that wave diffusivity …

Go to article

Development And Evaluation Of Recurrent Neural Network-Based Models For Hourly Traffic Volume And Annual Average Daily Traffic Prediction, Zadid Khan, Sakib Mahmud Khan, Kakan Dey, Mashrur Chowdhury Jun 2019

Development And Evaluation Of Recurrent Neural Network-Based Models For Hourly Traffic Volume And Annual Average Daily Traffic Prediction, Zadid Khan, Sakib Mahmud Khan, Kakan Dey, Mashrur Chowdhury

Publications

The prediction of high-resolution hourly traffic volumes of a given roadway is essential for transportation planning. Traditionally, automatic traffic recorders (ATR) are used to collect these hourly volume data. These large datasets are time-series data characterized by long-term temporal dependencies and missing values. Regarding the temporal dependencies, all roadways are characterized by seasonal variations that can be weekly, monthly or yearly, depending on the cause of the variation. Traditional time-series forecasting models perform poorly when they encounter missing data in the dataset. To address this limitation, robust, recurrent neural network (RNN)-based, multi-step-ahead forecasting models are developed for time-series in this …

Go to article

Effects Of The Hall Conductivity In Ionospheric Heating Experiments, B. Tulegenov, A. V. Streltsov May 2019

Effects Of The Hall Conductivity In Ionospheric Heating Experiments, B. Tulegenov, A. V. Streltsov

Publications

We investigate the role of Hall conductivity in ionospheric heating experiments. Ionosphericheating by powerful X-mode waves changes the Hall and Pedersen conductances in theEandDregions,which lead to the generation of ultra-low frequency (ULF)/extremely-low frequency/very low frequencywaves, when the electric field exists in the ionosphere. The importance of the Hall currents in themagnetosphere-ionosphere interactions, carried by ULF waves and field-aligned currents, has beenconsistently overlooked in studies devoted tothe active experiments. Simulations of the three-dimensionaltwo-fluid magnetohydrodynamic (MHD) model, presented in this paper, demonstrate that the Hallconductivity changes (1) the growth rate and the amplitude of ULF waves generated by the heating and (2)the …

Go to article

Formative Assessment Techniques For Online Learning, Emily Faulconer, Beverly Wood May 2019

Formative Assessment Techniques For Online Learning, Emily Faulconer, Beverly Wood

Publications

While most faculty think of assessments as used to measure learning after the fact, formative assessment classroom techniques (FACTs) give an instructor a snapshot of where students are in their learning so as to address any gaps in their understanding. Online instructors have a variety of tools at their disposal to incorporate engaging FACTs into their courses that will improve learning outcomes.

Go to article

A 3+1 Decomposition Of The Minimal Standard-Model Extension Gravitational Sector, Nils A. Nilsson, Kellie O'Neal-Ault, Quentin G. Bailey May 2019

A 3+1 Decomposition Of The Minimal Standard-Model Extension Gravitational Sector, Nils A. Nilsson, Kellie O'Neal-Ault, Quentin G. Bailey

Publications

The 3+1 (ADM) formulation of General Relativity is used in, for example, canonical quantum gravity and numerical relativity. Here we present a 3+1 decomposition of the minimal Standard-Model Extension gravity Lagrangian. By choosing the leaves of foliation to lie along a timelike vector field we write the theory in a form which will allow for comparison and matching to other gravity models.

Go to article

Multimodal Emotion Classification, Anurag Illendula, Amit Sheth May 2019

Multimodal Emotion Classification, Anurag Illendula, Amit Sheth

Publications

Most NLP and Computer Vision tasks are limited to scarcity of labelled data. In social media emotion classification and other related tasks, hashtags have been used as indicators to label data. With the rapid increase in emoji usage of social media, emojis are used as an additional feature for major social NLP tasks. However, this is less explored in case of multimedia posts on social media where posts are composed of both image and text. At the same time, w.e have seen a surge in the interest to incorporate domain knowledge to improve machine understanding of text. In this paper, …

Go to article

Recent Developments In Spacetime-Symmetry Tests In Gravity, Q. G. Bailey May 2019

Recent Developments In Spacetime-Symmetry Tests In Gravity, Q. G. Bailey

Publications

Motivated by potentially detectable but minuscule signatures from Planckscale or other new physics, there has been a substantial increase in tests of spacetime symmetry in gravity in recent years. Some novel hypothetical effects that break local Lorentz symmetry and CPT symmetry in gravitational experiments as well as solar system and astrophysical observations have been studied in recent works. Much of this work uses the effective field theory framework, the Standard-Model Extension (SME), that includes gravitational couplings. In other cases, the parameters in specific hypothetical models of Lorentz violation in gravity have been tested.

Go to article

On The Long Lasting “C‐Type” Structures In The Sodium Lidargram: The Lifetime Of Kelvin‐Helmholtz Billows In The Mesosphere And Lower Thermosphere Region, S. Mondal, S. Sarkhel, Jay Agarwal, D. Chakrabarty, R. Sekar, Tao Yuan, Alan Z. Liu, Et Al. Apr 2019

On The Long Lasting “C‐Type” Structures In The Sodium Lidargram: The Lifetime Of Kelvin‐Helmholtz Billows In The Mesosphere And Lower Thermosphere Region, S. Mondal, S. Sarkhel, Jay Agarwal, D. Chakrabarty, R. Sekar, Tao Yuan, Alan Z. Liu, Et Al.

Publications

In order to understand the characteristics of long‐lasting “C‐type” structure in the Sodium (Na) lidargram, six cases from different observational locations have been analyzed. The Na lidargram, collected from low‐, middle‐, and high‐latitude sites, show long lifetime of the C‐type structures which is believed to be the manifestation of Kelvin‐Helmholtz (KH) billows in the Mesosphere and Lower Thermosphere (MLT) region. In order to explore the characteristics of the long‐lasting C‐type structures, the altitude profile of square of Brunt‐Väisälä frequency in the MLT region has been derived using the temperature profile collected from the Na lidar instruments and the SABER instrument …

Go to article

Artificial Aurora Produced By Haarp, B. Tulegenov, A. V. Streltsov, E. Kendall, M. Mccarrick, I. Galkin Apr 2019

Artificial Aurora Produced By Haarp, B. Tulegenov, A. V. Streltsov, E. Kendall, M. Mccarrick, I. Galkin

Publications

We present results from the ionospheric heating experiment conducted at the HighFrequency Active Auroral Research Program (HAARP) facility, Alaska, on 12 March 2013. During theexperiment, HAARP transmitted in the direction of the magnetic zenith X-mode 4.57-MHz wave. Thetransmitted power was modulated with the frequency of 0.9 mHz, and it was pointed on a 20-km spot at thealtitude of 120 km. The heating (1) generates disturbances in the magnetic field detected with the fluxgatemagnetometer on the ground and (2) produces bright luminous spots in the ionosphere, observed with theHAARP telescope. Numerical simulations of the 3-D reduced magnetohydrodynamic (MHD) model revealthat these …

Go to article

Gravity Wave Ducting Observed In The Mesosphere Over Jicamarca, Peru, Gerald A. Lehmacher, Christopher J. Heale, Jonathan B. Snively, Erhan Kudeki, Pablo M. Reyes, Kiwook Lee Apr 2019

Gravity Wave Ducting Observed In The Mesosphere Over Jicamarca, Peru, Gerald A. Lehmacher, Christopher J. Heale, Jonathan B. Snively, Erhan Kudeki, Pablo M. Reyes, Kiwook Lee

Publications

Short-period gravity waves are ubiquitous in the mesosphere, but the vertical structures of their perturbations are difficult to observe. The Jicamarca 50-MHz very high frequency radar allows observations of winds and turbulent scatter with high temporal and vertical resolution. We present a case of a quasi-monochromatic gravity wave with period 520 (±40) s that is likely ducted below a southward wind jet between 68 and 74 km. Above this layer of evanescence, a northward wind enables it to emerge into a more stable layer, where it is refracted to a short vertical wavelength of 2.2 (±0.2) km; data show evidence …

Go to article

Numerical Modeling Of The Propagation Of Infrasonic Acoustic Waves Through The Turbulent Field Generated By The Breaking Of Mountain Gravity Waves, Michael P. Hickey, Jonathan Snively, C Bailly, J. L. Garrison Apr 2019

Numerical Modeling Of The Propagation Of Infrasonic Acoustic Waves Through The Turbulent Field Generated By The Breaking Of Mountain Gravity Waves, Michael P. Hickey, Jonathan Snively, C Bailly, J. L. Garrison

Publications

The nonlinear propagation of low-frequency acoustic waves through the turbulent fluctuations induced by breaking mountain gravity waves is investigated via 2-D numerical simulations of the Navier-Stokes equations, to understand the effects of atmospheric dynamics on ground-based infrasound measurements. Emphasis is placed on acoustic signals of frequency around 0.1 Hz, traveling through tens-of-kilometers-scale gravity waves and subkilometer-scale turbulence. The sensitivity of the infrasonic phases to small-scale fluctuations is found to depend on the altitudes through which they are refracted toward the Earth. For the considered cases, the dynamics in the stratosphere impact the refracting acoustic waves to a greater extent than …

Go to article

Testing The Gravitational Weak Equivalence Principle In The Standard-Model Extension With Binary Pulsars, Lijing Shao, Quentin G. Bailey Apr 2019

Testing The Gravitational Weak Equivalence Principle In The Standard-Model Extension With Binary Pulsars, Lijing Shao, Quentin G. Bailey

Publications

The standard model extension provides a framework to systematically investigate possible violation of the Lorentz symmetry. Concerning gravity, the linearized version was extensively examined. We here cast the first set of experimental bounds on the nonlinear terms in the field equation from the anisotropic cubic curvature couplings. These terms introduce body-dependent accelerations for self-gravitating objects, thus violating the gravitational weak equivalence principle (GWEP). Novel phenomena, which are absent in the linearized gravity, remain experimentally unexplored. We constrain them with precise binary-orbit measurements from pulsar timing, wherein the high density and large compactness of neutron stars are crucial for the test. …

Go to article

Alpha Insurance: A Predictive Analytics Case To Analyze Automobile Insurance Fraud Using Sas Enterprise Miner (Tm), Richard Mccarthy, Wendy Ceccucci, Mary Mccarthy, Leila Halawi Apr 2019

Alpha Insurance: A Predictive Analytics Case To Analyze Automobile Insurance Fraud Using Sas Enterprise Miner (Tm), Richard Mccarthy, Wendy Ceccucci, Mary Mccarthy, Leila Halawi

Publications

Automobile Insurance fraud costs the insurance industry billions of dollars annually. This case study addresses claim fraud based on data extracted from Alpha Insurance’s automobile claim database. Students are provided the business problem and data sets. Initially, the students are required to develop their hypotheses and analyze the data. This includes identification of any missing or inaccurate data values and outliers as well as evaluation of the 22 variables. Next students will develop and optimize their predictive models using five techniques: regression, decision tree, neural network, gradient boosting, and ensemble. Then students will determine which model is the best fit …

Go to article

Gaia, White Dwarfs, And The Age Of The Galaxy, Ted Von Hippel, E.J. Jeffery, David Van Dyk, D.C. Stenning, E. Robinson, W.H. Jefferys Apr 2019

Gaia, White Dwarfs, And The Age Of The Galaxy, Ted Von Hippel, E.J. Jeffery, David Van Dyk, D.C. Stenning, E. Robinson, W.H. Jefferys

Publications

The Milky Way is composed of four major stellar populations: the thin disk, thick disk, bulge, and halo. At present, we do not know the age of any of these populations to better than one or two billion years. This lack of knowledge keeps us from answering fundamental questions about the Galaxy: When did the thin disk, thick disk, and halo form? Did they form over an extended period, and if so, how long? Was star formation continuous across these populations or instead occur in distinct episodes? The Gaia satellite is providing precise trigonometric parallaxes for a plethora of white …

Go to article

First Prev Next Last