Digital Commons Network^™

Bridging The Informal And Formal Learning Spaces With Whatsapp, Tutaleni I. Asino, Nandita Gurjar, Perien Boer

Faculty Publications

When it comes to digital-based learning, the question of engagement and presence is often focused on online learning involving traditional computing devices such as desktop computers or laptops. However, in areas where mobile devices are the most widely used computing technology, engagement and interaction between teachers and students looks different. In many parts of the world, interactions between individuals takes place through mobile texting applications to bridge formal and informal learning spaces.

One of the most popular mobile tools is WhatsApp, a free cross-platform mobile application that allows users to make calls (voice) and send messages (text). The app averages …

A Learning Curve Model Accounting For The Flattening Effect In Production Cycles, Evan R. Boone, John J. Elshaw, Clay M. Koschnick, Jonathan D. Ritschel, Adedeji B. Badiru

Faculty Publications

We investigate production cost estimates to identify and model modifications to a prescribed learning curve. Our new model examines the learning rate as a decreasing function over time as opposed to a constant rate that is frequently used. The purpose of this research is to determine whether a new learning curve model could be implemented to reduce the error in cost estimates for production processes. A new model was created that mathematically allows for a “flattening effect,” which typically occurs later in the production process. This model was then compared to Wright’s learning curve, which is a popular method used …

Use Of Factors In Development Estimates: Improving The Cost Analysis Toolkit, Matthew R. Markman, Jonathan D. Ritschel, Edward D. White

Faculty Publications

Factor Estimating is a technique commonly used by defense acquisition analysts to develop cost estimations. However, previous studies developing factors for the Engineering and Manufacturing Development (EMD) phase of the life cycle are limited. This research expands the current toolkit for cost analysts by developing cost factors in previously unexplored areas. More specifically, over 400 cost reports are utilized to create new standard cost factors that are delineated by five categories: commodity type, contract type, contractor type, development type, and Service. The factors are developed for those elements that are common in a wide array of projects such as program …

Sample Size Matters When Calculating Pillai Scores, Joseph A. Stanley, Betsy Sneller

Faculty Publications

Pillai Scores

Are they good measures?

• Often supported in meta-analyses (Nycz & Hall-Lew 2013, Kelley & Tucker 2020)
• Appear to be better than Euclidean distance, mixed-effects regression, spectral overlap, SOAM, VOACH, APP, etc.
• However, Bhattacharyya’s Affinity may be better suited for vowel data since it’s robust to skewed data. (Johnson 2015)

Implications:

Mergers are probably underreported and separation is probably overreported

• It takes a lot of data (more than many studies use) to get reliably low Pillai scores
• Mergers may be more common previously reported

Statistical significance should be reported

• Reporting p -values from MANOVA tests removes the need for …

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Worse Than Human?, Michael Risch, Derek E. Bambauer

Faculty Publications

The rise of algorithm-driven decision making enabled by Big Data has generated widespread concern among legal scholars. However, few critics have considered data on people’s existing preferences about the role of algorithms in decision systems. This Article uses empirical analysis of a novel, large dataset of consumer surveys to elucidate those preferences. The surveys explore whether people prefer to have an algorithm or a human determine an outcome affecting their welfare in a range of representative scenarios with varying stakes. The Article examines how preferences change when one type of decisionmaker produces results that are more accurate, faster, cheaper, or …

Preparing Teachers To Teach In K-12 Blended Environments: A Systematic Mapping Review Of Research Trends, Impact, And Themes, Cecil R. Short, Charles R. Graham, Theresa Holmes, Laura Oviatt, Hannah Bateman

Faculty Publications

No abstract provided.

Blockchain Technology: A Survey Of Croatian Business Leaders, Dražen Zec, William G. Heninger

Faculty Publications

Blockchain or distributed ledger technology emerged over ten years ago as the underlying technology of bitcoin. Blockchain is a special kind of database with individual records or blocks linked together in a sequential list called chain of blocks. These records are validated by multiple nodes in peer-to-peer networks and they are immutable. It is a decentralized system, with no need for intermediaries where all decisions are made using different consensus mechanisms. High expectations from blockchain technology, combined with a lack of deeper knowledge about the technology are expressed in the results from the survey conducted on a sample of Croatian …

Can User Interface Design Choices Alter Perceptions Of Time Passage?, James Gaskin

Faculty Publications

When a task is dull, time seems to unhelpfully dilate. This can have serious impacts on job satisfaction, burnout, and turnover – all of which impact employee well-being and the bottom line. Without changing the task, could a user interface take advantage of psychology-driven, theoretically-supported design decisions to make time seem to contract? If such is the case, we might, without much cost, partially alleviate employee suffering due to task fatigue and disinterest by making simple changes to the user interface. While psychology research and user interface design have intersected abundantly in extant literature, no study has empirically tested whether …

What Can Mental Health Teach Us About Social Media Screen Time Misestimation?, Mark Keith, Parker Nokes, Alexandra Spruill

Faculty Publications

Mobile platform providers have provided the ability to measure the time consumers spend on each app. This provides the opportunity to measure a consumer’s misestimation of their screentime which is a concept relevant to several mental health attributes such as depression, anxiety, and addiction. We provide additional evidence about the effect of objective screentime on mental health, but add a unique perspective on how screentime misestimation is determined by various mental health attributes. We collected data from a student sample (n=1005) who are from the demographic who most commonly use social media apps (18-29 yr olds). We measured our model …

Who Gets ‘To Guru’? Scientist Ted Speakers And The Role Of Collective Identity In Peer Evaluation Of Audience Diversification, Brian P. Reschke, Taeya M. Howell

Faculty Publications

As producers diversify to additional audiences, they invite scrutiny of themselves and the products they provide, both by external evaluators as well as peer producers. We argue that in certain conditions, audience diversification may suggest producers represent their producer group, prompting special scrutiny by peers. In these cases, peer evaluation of diversification depends on the correspondence between the identity of the diversifying producer and the collective identity of the producer group, such that peers sanction non-prototypical producers and support exemplary producers. We develop and test hypotheses in the context of science, examining how appeals to the general public—giving a TED …

Reducing Wind Farm Power Variance From Wind Direction Using Wind Farm Layout Optimization, Bertelsen Gagakuma, Andrew P.J. Stanley, Andrew Ning

Faculty Publications

This paper investigates reducing power variance caused by different wind directions by using wind farm layout optimization. The problem was formulated as a multi-objective optimization. The ε−constraint method was used to solve the bi-objective problem in a two-step optimization framework where two sequential optimizations were performed. The first was maximizing the mean wind farm power alone and the second was minimizing the power variance with a constraint on the mean power. The results show that the variance in power estimates can be greatly reduced, by as much as 30%, without sacrificing mean plant power for the different farm sizes and …

Quantifying The Effects Of Aircraft Engine Upgrades On Operating And Support Costs, Bradford A. Myers, Edward D. White, Jonathan D. Ritschel, R. David Fass

Faculty Publications

For fixed wing aircraft within the U.S. Air Force, Operating and Support (O&S) costs encompass a large portion of total life cycle costs. O&S costs include fuel, maintenance, and engine upgrades. To the authors’ knowledge, no study to date has attempted to empirically quantify the realized effects of new aircraft engines on sustainment costs. Utilizing the Air Force Total Ownership Cost database, they focused on new engines appearing on the C-5s, C-130s, and C-135s. Although narrow in scope, results suggest newer engines have lower fuel costs. Maintenance costs for newer engines were not consistently higher or lower than the engines …

Varieties Of Adventists After 1844: Emerging From “Fanaticism Of Every Kind” Into “The Order Of Heaven”, David J. B. Trim

Faculty Publications

No abstract provided.

A Case Study Of Avocado, Berry, And Apple Trade Through Nafta, Jose A. Lopez, Hovhannes Mnatsakanyan

Faculty Publications

A Source-Differentiated Almost Ideal Demand System (SDAIDS) model was estimated for berries, apples, and avocadoes imported through NAFTA prior to the new USMCA. Elasticity estimates are useful for measuring consumers’ responsiveness to changes in fresh-fruit prices or expenditures. This study found the demands for berries, apples, and avocadoes were price inelastic; and that cases of substitute fresh-fruit imports were more frequent than complements. The study also assessed expected changes in US fresh-fruit imports through NAFTA in the wake of a tariff on Mexican fresh fruits as frequently propagated by politicians in the news. The combined direct and indirect impacts from …

Open Data From The First And Second Observing Runs Of Advanced Ligo And Advanced Virgo, Ligo Scientific Collaboration, Virgo Collaboration, Tiffany Z. Summerscales

Faculty Publications

Advanced LIGO and Advanced Virgo are monitoring the sky and collecting gravitational-wave strain data with sufficient sensitivity to detect signals routinely. In this paper we describe the data recorded by these instruments during their first and second observing runs. The main data products are gravitational-wave strain time series sampled at 16384 Hz. The datasets that include this strain measurement can be freely accessed through the Gravitational Wave Open Science Center at http://gw-openscience.org, together with data-quality information essential for the analysis of LIGO and Virgo data, documentation, tutorials, and supporting software.

Design And Catastrophe: 51 Scientists Explore Evidence In Nature, Gordon J. Atkins

Faculty Publications

Review of

L. James Gibson, Ronny Nalin, and Humberto M. Rasi, eds. Design and Catastrophe: 51 Scientists Explore Evidence in Nature (Berrien Springs, Mich.: Andrews University Press, 2021). ISBN: 9781940980305 (Print). 240 pages (Hardback), US$24.99.

A Radial Basis Function Finite Difference Scheme For The Benjamin–Ono Equation, Benjamin F. Akers, Tony Liu, Jonah A. Reeger

Faculty Publications

A radial basis function-finite differencing (RBF-FD) scheme was applied to the initial value problem of the Benjamin–Ono equation. The Benjamin–Ono equation has traveling wave solutions with algebraic decay and a nonlocal pseudo-differential operator, the Hilbert transform. When posed on ℝ, the former makes Fourier collocation a poor discretization choice; the latter is challenging for any local method. We develop an RBF-FD approximation of the Hilbert transform, and discuss the challenges of implementing this and other pseudo-differential operators on unstructured grids. Numerical examples, simulation costs, convergence rates, and generalizations of this method are all discussed.

Salt Marsh Elevation Limit Determined After Subsidence From Hydrologic Change And Hydrocarbon Extraction, R. Eugene Turner, Yu Mo

Faculty Publications

Levee construction aboveground and hydrocarbon removal from belowground in coastal wetlands can create hydrologic changes that increase plant stress through flooding. But the significance of the subsidence they cause individually or in combination is contested. This study untangled them to demonstrate elevational limits of salt marshes by studying dredged and natural waterways in two salt marshes in Louisiana, USA. The areas had a homogenous plant cover before drilling for oil and gas extraction peaked in the 1960s, and now are a mixed network of natural waterways and dredged canals used to drill wells with an average drill date of 1965.8 …

The Supercam Instrument Suite On The Nasa Mars 2020 Rover: Body Unit And Combined System Tests, Roger C. Wiens, Sylvestre Maurice, Scott H. Robinson, Anthony E. Nelson, Philippe Cais, Pernelle Bernardi, Raymond T. Newell, Sam Clegg, Shiv K. Sharma, Steven Storms, Jonathan Deming, Darrel Beckman, Ann M. Ollila, Olivier Gasnault, Ryan B. Anderson, Yves André, Stanley M. Angel, Gorka Arana, Elizabeth Auden, Pierre Beck, Et. Al.

Faculty Publications

The SuperCam instrument suite provides the Mars 2020 rover, Perseverance, with a number of versatile remote-sensing techniques that can be used at long distance as well as within the robotic-arm workspace. These include laser-induced breakdown spectroscopy (LIBS), remote time-resolved Raman and luminescence spectroscopies, and visible and infrared (VISIR; separately referred to as VIS and IR) reflectance spectroscopy. A remote micro-imager (RMI) provides high-resolution color context imaging, and a microphone can be used as a stand-alone tool for environmental studies or to determine physical properties of rocks and soils from shock waves of laser-produced plasmas. SuperCam is built in three parts: …

Spectral Absorption Coefficient Of Additive Manufacturing Materials, Nicholas J. Wallace, Matthew R. Jones, Nathan B. Crane

Faculty Publications

Active thermography techniques are of interest for quality assurance of additive manufacturing processes. However, accurate measurements of thermophysical properties of materials are required to successfully implement active thermography. In particular, the spectral absorption coefficient of materials commonly used in additive manufacturing must be known to accurately predict the spatial distribution of thermal energy generated from absorption of power emitted by a laser or pulsed flash lamp. Accurate measurements of these optical properties are also needed to develop greater understanding of additive manufacturing processes that rely on radiative heat transfer to fuse powders. This paper presents spectral absorption coefficient measurements and …

Comparing Greedy Constructive Heuristic Subtour Elimination Methods For The Traveling Salesman Problem, Petar Jackovich, Bruce A. Cox, Raymond R. Hill

Faculty Publications

Purpose — This paper aims to define the class of fragment constructive heuristics used to compute feasible solutions for the traveling salesman problem (TSP) into edge-greedy and vertex-greedy subclasses. As these subclasses of heuristics can create subtours, two known methodologies for subtour elimination on symmetric instances are reviewed and are expanded to cover asymmetric problem instances. This paper introduces a third novel subtour elimination methodology, the greedy tracker (GT), and compares it to both known methodologies. Design/methodology/approach — Computational results for all three subtour elimination methodologies are generated across 17 symmetric instances ranging in size from 29 vertices to 5,934 …

Modified C-17 Taxi Procedures: A Fuel Cost Savings Exploration, Michael Wells, Michael Krester, Benjamin Hazen, Jeffery D. Weir

Faculty Publications

Purpose — This study aims to explore the viability of using C-17 reduced-engine taxi procedures from a cost savings and capability perspective. Design/methodology/approach — This study model expected engine fuel flow based on the number of operational engines, aircraft gross weight (GW) and average aircraft groundspeed. Using this model, the research executes a cost savings simulation estimating the expected annual savings produced by the proposed taxi methodology. Operational and safety risks are also considered. Findings — The results indicate that significant fuel and costs savings are available via the employment of reduced-engine taxi procedures. On an annual basis, the mobility …

Direct Measurement Of The Cosmic-Ray Carbon And Oxygen Spectra From 10 Gev/ N To 2.2 Tev/ N With The Calorimetric Electron Telescope On The International Space Station, O. Adriani, Y. Akaike, K. Asano, Y. Asaoka, M. G. Bagliesi, E. Berti, G. Bigongiari, W. R. Binns, M. Bongi, P. Brogi, A. Bruno, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, K. Ebisawa, H. Fuke, S. Gonzi, T. G. Guzik, T. Hams, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka

Faculty Publications

In this paper, we present the measurement of the energy spectra of carbon and oxygen in cosmic rays based on observations with the Calorimetric Electron Telescope on the International Space Station from October 2015 to October 2019. Analysis, including the detailed assessment of systematic uncertainties, and results are reported. The energy spectra are measured in kinetic energy per nucleon from 10 GeV/n to 2.2 TeV/n with an all-calorimetric instrument with a total thickness corresponding to 1.3 nuclear interaction length. The observed carbon and oxygen fluxes show a spectral index change of ∼0.15 around 200 GeV/n established with a significance >3σ. …

Destabilizing Effects On A Classic Tri-Trophic Oyster Reef Cascade, Virginia R. Schweiss, Chet F. Rakocinski

Faculty Publications

How interactions among multiple predators affect the stability of trophic cascades is a topic of special ecological interest. To examine factors affecting the stability of the classic tri-trophic oyster reef cascade within a different context, configurations of three predators, including the Gulf toadfish, Gulf stone crab, and oystershell mud crab, were manipulated together with either oyster shell or limestone gravel substrate within a multiple predator effects (MPE) experiment. Additionally, a complimentary set of trait-mediated-indirect interaction (TMII) experiments examined the inhibition of oyster consumption relative to mud-crab size and top predator identity in the absence of other cues and factors. The …

Precision Measurement Of The Ratio Β(Y(3S) → Τ + Τ−) / Β( Y(3S)→ Μ+ Μ−, J. P. Lees, V. Poireau, V. Tisserand, E. Grauges, A. Palano, G. Eigen, D. N. Brown, Yu. G. Kolomensky, M. Fritsch, H. Koch, T. Schroeder, R. Cheaib, C. Hearty, T. S. Mattison, J. A. Mckenna, R. Y. So, V. E. Blinov, A. R. Buzykaev, V. P. Druzhinin, Milind Purohit, Et. Al.

Faculty Publications

We report on a precision measurement of the ratio Rϒð3SÞ τμ ¼ Bðϒð3SÞ → τþτ−Þ=Bðϒð3SÞ → μþμ−Þ using data collected with the BABAR detector at the SLAC PEP-II eþe− collider. The measurement is based on a 28 fb−1 data sample collected at a center-of-mass energy of 10.355 GeV corresponding to a sample of 122 million ϒð3SÞ mesons. The ratio is measured to be Rϒð3SÞ τμ ¼ 0.966 0.008stat 0.014syst and is in agreement with the standard model prediction of 0.9948 within 2 standard deviations. The uncertainty in Rϒð3SÞ τμ is almost an order of magnitude smaller than the only previous …

One-Dimensional Turbulence (Odt): Computationally Efficient Modeling And Simulation Of Turbulent Flows, Victoria B. Stephens, David O. Lignell

Faculty Publications

One-dimensional turbulence (ODT) is an accurate and computationally efficient model for simulating turbulent flows. ODT has been applied to a wide range of flow problems including reaction, multiphase, differential diffusion, heat release, buoyancy, and wall flows. Applications include use as a standalone model and as a closure for large-eddy simulation (LES). Its strength lies in the ability to capture a full range of turbulent length and time scales. The ODT model is strongly coupled with its implementation, complicating its formulations. We present a modern, open-source, object-oriented C++ implementation of ODT. The code described here and made available online can be …

Search For Gravitational Waves From Scorpius X-1 In The Second Advanced Ligo Observing Run With An Improved Hidden Markov Model, Tiffany Summerscales, Ligo Scientific Collaboration And The Virgo Collaboration

Faculty Publications

We present results from a semicoherent search for continuous gravitational waves from the low-mass x-ray binary Scorpius X-1, using a hidden Markov model (HMM) to track spin wandering. This search improves on previous HMM-based searches of LIGO data by using an improved frequency domain matched filter, the J-statistic, and by analyzing data from Advanced LIGO’s second observing run. In the frequency range searched, from 60 to 650 Hz, we find no evidence of gravitational radiation. At 194.6 Hz, the most sensitive search frequency, we report an upper limit on gravitational wave strain (at 95% confidence) of h95%0=3.47×10−25 when marginalizing over …

First Results On Protodune-Sp Liquid Argon Time Projection Chamber Performance From A Beam Test At The Cern Neutrino Platform, B. Abi, A. Abed Abud, R. Acciarri, M. A. Acero, G. Adamowski, D. Adams, P. Adrien, M. Adinolfi, Z. Ahmad, J. Ahmed, T. Alion, S. Alonso Monsalve, C. Alt, J. Anderson, C. Andreopoulos, M. P. Andrews, F. Andrianala, S. Andringa, A. Ankowski, M. Antonova, Roberto Petti, Et. Al.

Faculty Publications

The ProtoDUNE-SP detector is a single-phase liquid argon time projection chamber with an active volume of 7.2 × 6.1 × 7.0 m³ . It is installed at the CERN Neutrino Platform in a specially-constructed beam that delivers charged pions, kaons, protons, muons and electrons with momenta in the range 0.3 GeV/�� to 7 GeV/��. Beam line instrumentation provides accurate momentum measurements and particle identification. The ProtoDUNE-SP detector is a prototype for the first far detector module of the Deep Underground Neutrino Experiment, and it incorporates full-size components as designed for that module. This paper describes the beam line, the …

Strengthening Spatial Reasoning: Elucidating The Attentional And Neural Mechanisms Associated With Mental Rotation Skill Development, Katherine C. Moen, Melissa R. Beck, Stephanie M. Saltzmann, Tovah M. Cowan, Lauryn M. Burleigh, Leslie G. Butler, Jagannathan Ramanujam, Alex S. Cohen, Steven G. Greening

Faculty Publications

© 2020, The Author(s). Spatial reasoning is a critical skill in many everyday tasks and in science, technology, engineering, and mathematics disciplines. The current study examined how training on mental rotation (a spatial reasoning task) impacts the completeness of an encoded representation and the ability to rotate the representation. We used a multisession, multimethod design with an active control group to determine how mental rotation ability impacts performance for a trained stimulus category and an untrained stimulus category. Participants in the experimental group (n = 18) showed greater improvement than the active control group (n = 18) on the mental …

Qcm Sensor Arrays, Electroanalytical Techniques And Nir Spectroscopy Coupled To Multivariate Analysis For Quality Assessment Of Food Products, Raw Materials, Ingredients And Foodborne Pathogen Detection: Challenges And Breakthroughs†, David K. Bwambok, Noureen Siraj, Samantha Macchi, Nathaniel E. Larm, Gary A. Baker, Rocío L. Pérez, Caitlan E. Ayala, Charuksha Walgama, David Pollard, Jason D. Rodriguez, Souvik Banerjee, Brianda Elzey, Isiah M. Warner, Sayo O. Fakayode

Faculty Publications

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. Quality checks, assessments, and the assurance of food products, raw materials, and food ingredients is critically important to ensure the safeguard of foods of high quality for safety and public health. Nevertheless, quality checks, assessments, and the assurance of food products along distribution and supply chains is impacted by various challenges. For instance, the development of portable, sensitive, low-cost, and robust instrumentation that is capable of real-time, accurate, and sensitive analysis, quality checks, assessments, and the assurance of food products in the field and/or in the production line in a food …