Physical Sciences and Mathematics Commons^™

Applicability And Estimation Of Error For Determination Of Hydraulic Conductivity Values Based Upon Traditional Aquifer Test Methods For 2-D Groundwater Modeling, Timothy W. Freed Sr.

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

The Theis method and its derivative Cooper-Jacob method are commonly used for determining hydraulic conductivity (K) for aquifer studies using two-dimensional (2-D) groundwater modeling. Theis and derivative equations assume isotropic, homogeneous aquifers and horizontal flow. In nature, saturated permeable layers of an aquifer are often separated by less permeable layers or lenses, which commonly have K's that are lower by several orders of magnitude. The presence of such geologic features induces vertical flow during aquifer tests violating assumptions for Theis based methods. This study assesses the appropriateness and error of using Theis based equations to determine K for use in …

Reputation As Public Policy For Internet Security, Leigh L. Linden, John S. Quarterman, Qian Tang, Andrew B. Whinston

Research Collection School Of Computing and Information Systems

Insufficient resource allocation causes an Internet information security (infosec) problem that public policy could improve. Lack of transparency lets organizations avoid addressing internal risks, leaving vulnerabilities that are exploited by botnets, threatening information security of other Internet participants. Their protection provides no economic benefit to the firm, so this negative externality causes underinvestment in infosec. Public policy could provide a partial solution by adding incentives for organizations to have well-configured infosec. Specifically, mandatory reporting of security issues plus presenting this information to the public, can impose shame and fame on organizations through publicity and peer influence by comparison with major …

Forecasting The Effect Of The Amethyst Initiative On College Drinking, Ben G. Fitzpatrick, Richard Scribner, Azmy S. Ackleh, Jawaid Rasul, Geoffrey Jacquez, Neal Simonsen, Robert Rommel

Mathematics Faculty Works

Background

A number of college presidents have endorsed the Amethyst Initiative, a call to consider lowering the minimum legal drinking age (MLDA). Our objective is to forecast the effect of the Amethyst Initiative on college drinking.

Methods

A system model of college drinking siumlates MLDA changes through (1) a decrease in heavy episodic drinking (HED) due to the lower likelihood of students drinking in unsupervised settings where they model irresponsible drinking (misperception), and (2) an increase in overall drinking among currently underage students due to increased social availability of alcohol (wetness).

Results

For the proportion of HEDs on campus, effects …

Cosm News, Georgia Southern University

College of Science and Mathematics News (2012-2019)

• Mathematical Competition in Modeling (MCM) Spring 2012

Water And Energy Balance Response Of A Riparian Wetland To The Removal Of Phragmites Australis, Phillip Mykleby

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Vegetation and climate both play integral roles in water availability, particularly for arid to semi-arid regions. Changes in these variables can lead to extreme shortages in water for regions that rely on water for crop irrigation (i.e., the Great Plains). The objective of this study is to evaluate the impacts of vegetation on water availability in the Republican River basin in central Nebraska. Decreases in streamflow have been observed in the river basin for many years and, as a result, an invasive riparian plant species (Phragmites australis) is being removed in an effort to reduce evapotranspiration and reclaim …

Childhood Body Mass Index Trajectories: Modeling, Characterizing, Pairwise Correlations And Socio-Demographic Predictors Of Trajectory Characteristics, Xiaozhong Wen, Ken Kleinman, Matthew W. Gillman, Sherly L. Rifas-Shiman, Elsie M. Taveras

Public Health Department Faculty Publication Series

BACKGROUND:

Modeling childhood body mass index (BMI) trajectories, versus estimating change in BMI between specific ages, may improve prediction of later body-size-related outcomes. Prior studies of BMI trajectories are limited by restricted age periods and insufficient use of trajectory information.

METHODS:

Among 3,289 children seen at 81,550 pediatric well-child visits from infancy to 18 years between 1980 and 2008, we fit individual BMI trajectories using mixed effect models with fractional polynomial functions. From each child's fitted trajectory, we estimated age and BMI at infancy peak and adiposity rebound, and velocity and area under curve between 1 week, infancy peak, adiposity …

Simulation Of Coastal Inundation Instigated By Storm Surge And River Discharge In The Chesapeake Bay Using Sub-Grid Modeling Coupled With Lidar Data, J. D. Loftis, H. V. Wang

Presentations

Sub-grid modeling is a novel method by which water level elevations on the sub-grid level can be obtained through the combination of water levels and velocities efficiently calculated at the coarse computational grid, the discretized bathymetric depths, and local friction parameters without resorting to solve the full set of equations. Sub-grid technology essentially allows velocity to be determined rationally and efficiently at the sub-grid level. This salient feature enables coastal flooding to be addressed in a single cross-scale model from the ocean to the upstream river channel without overly refining the grid resolution. To this end, high-resolution DEMs will be …

Dynamical Random-Set Modeling Of Concentrated Precipitation In North America, Noel Cressie, Renato Assuncao, Scott H. Holan, Michael Levine, Orietta Nicolis, Jun Zhang, Jian Zou

Faculty of Informatics - Papers (Archive)

In order to study climate at scales where policy decisions can be made, regional climate models (RCMs) have been developed with much finer resolution (~50 km) than the ~500 km resolution of atmosphere-ocean general circulation models (AOGCMs). The North American Regional Climate Change Assessment Program (NARCCAP) is an international program that provides 50-km resolution climate output for the United States, Canada, and northern Mexico. In Phase I, there are six RCMs, from which we choose one to illustrate our methodology. The RCMs are updated every 3 hours and contain a number of variables, including temperature, precipitation, wind speed, wind direction, …

Muscle Organization In Individuals With And Without Pain And Joint Dysfunction, J. C. Nickel, Y. M. Gonzalez, W. D. Mccall, R. Ohrbach, D. B. Marx, H. Liu, L. R. Iwasaki

Department of Statistics: Faculty Publications

Central nervous system organization of masticatory muscles determines the magnitude of joint and muscle forces. Validated computer-assisted models of neuromuscular organization during biting were used to determine organization in individuals with and without temporomandibular disorders (TMD). Ninety-one individuals (47 women, 44 men) were assigned to one of four diagnostic groups based on the presence (+) or absence (-) of pain (P) and bilateral temporomandibular joint disc displacement (DD). Electromyography and bite-forces were measured during right and left incisor and molar biting. Two three-dimensional models employing neuromuscular objectives of minimization of joint loads (MJL) or muscle effort (MME) simulated biting tasks. …

Investigating Forest Inventory And Analysis-Collected Tree-Ring Data From Utah As A Proxy For Historical Climate, R. Justin Derose, Shih-Yu (Simon) Wang, John D. Shaw

Wasatch Dendroclimatology Research

Increment cores collected as part of the periodic inventory in the Intermountain West were examined for their potential to represent growth and be a proxy for climate (precipitation) over a large region (Utah). Standardized and crossdated time-series created from pinyon pine (n=249) and Douglas-fir (n=274) increment cores displayed spatiotemporal patterns in growth differences both between species and by region within Utah. However, the between-species interrelationship of growth was strong over much of the state and indicated both species respond similarly to climate variations. Indeed, pinyon pine and Douglas-fir exhibited a significant and spatially coherent response to instrumental precipitation data. Previous …