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Probabilistic Modeling and Regression Analysis of Experimental Data for Structural Systems

Description
The Experimental Data Processing (EDP) software is a C++ GUI-based application to streamline the process of creating a model for structural systems based on experimental data. EDP is designed to process raw data, filter the data for noise and outliers, create a fitted model to describe that data, complete a…

The Experimental Data Processing (EDP) software is a C++ GUI-based application to streamline the process of creating a model for structural systems based on experimental data. EDP is designed to process raw data, filter the data for noise and outliers, create a fitted model to describe that data, complete a probabilistic analysis to describe the variation between replicates of the experimental process, and analyze reliability of a structural system based on that model. In order to help design the EDP software to perform the full analysis, the probabilistic and regression modeling aspects of this analysis have been explored. The focus has been on creating and analyzing probabilistic models for the data, adding multivariate and nonparametric fits to raw data, and developing computational techniques that allow for these methods to be properly implemented within EDP. For creating a probabilistic model of replicate data, the normal, lognormal, gamma, Weibull, and generalized exponential distributions have been explored. Goodness-of-fit tests, including the chi-squared, Anderson-Darling, and Kolmogorov-Smirnoff tests, have been used in order to analyze the effectiveness of any of these probabilistic models in describing the variation of parameters between replicates of an experimental test. An example using Young's modulus data for a Kevlar-49 Swath stress-strain test was used in order to demonstrate how this analysis is performed within EDP. In order to implement the distributions, numerical solutions for the gamma, beta, and hypergeometric functions were implemented, along with an arbitrary precision library to store numbers that exceed the maximum size of double-precision floating point digits. To create a multivariate fit, the multilinear solution was created as the simplest solution to the multivariate regression problem. This solution was then extended to solve nonlinear problems that can be linearized into multiple separable terms. These problems were solved analytically with the closed-form solution for the multilinear regression, and then by using a QR decomposition to solve numerically while avoiding numerical instabilities associated with matrix inversion. For nonparametric regression, or smoothing, the loess method was developed as a robust technique for filtering noise while maintaining the general structure of the data points. The loess solution was created by addressing concerns associated with simpler smoothing methods, including the running mean, running line, and kernel smoothing techniques, and combining the ability of each of these methods to resolve those issues. The loess smoothing method involves weighting each point in a partition of the data set, and then adding either a line or a polynomial fit within that partition. Both linear and quadratic methods were applied to a carbon fiber compression test, showing that the quadratic model was more accurate but the linear model had a shape that was more effective for analyzing the experimental data. Finally, the EDP program itself was explored to consider its current functionalities for processing data, as described by shear tests on carbon fiber data, and the future functionalities to be developed. The probabilistic and raw data processing capabilities were demonstrated within EDP, and the multivariate and loess analysis was demonstrated using R. As the functionality and relevant considerations for these methods have been developed, the immediate goal is to finish implementing and integrating these additional features into a version of EDP that performs a full streamlined structural analysis on experimental data.
ContributorsMarkov, Elan Richard (Author) / Rajan, Subramaniam (Thesis director) / Khaled, Bilal (Committee member) / Chemical Engineering Program (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / Ira A. Fulton School of Engineering (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
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Genetic Population Structure Accounts for Contemporary Ecogeographic Patterns in Tropic and Subtropic-Dwelling Humans

Description

Contemporary human populations conform to ecogeographic predictions that animals will become more compact in cooler climates and less compact in warmer ones. However, it remains unclear to what extent this pattern reflects plastic responses to current environments or genetic differences among populations. Analyzing anthropometric surveys of 232,684 children and adults…

Contemporary human populations conform to ecogeographic predictions that animals will become more compact in cooler climates and less compact in warmer ones. However, it remains unclear to what extent this pattern reflects plastic responses to current environments or genetic differences among populations. Analyzing anthropometric surveys of 232,684 children and adults from across 80 ethnolinguistic groups in sub-Saharan Africa, Asia and the Americas, we confirm that body surface-to-volume correlates with contemporary temperature at magnitudes found in more latitudinally diverse samples (Adj. R2 = 0.14-0.28). However, far more variation in body surface-to-volume is attributable to genetic population structure (Adj. R2 = 0.50-0.74). Moreover, genetic population structure accounts for nearly all of the observed relationship between contemporary temperature and body surface-to-volume among children and adults. Indeed, after controlling for population structure, contemporary temperature accounts for no more than 4% of the variance in body form in these groups. This effect of genetic affinity on body form is also independent of other ecological variables, such as dominant mode of subsistence and household wealth per capita. These findings suggest that the observed fit of human body surface-to-volume with current climate in this sample reflects relatively large effects of existing genetic population structure of contemporary humans compared to plastic response to current environments.
ContributorsHruschka, Daniel (Author) / Hadley, Craig (Author) / Brewis, Alexandra (Author) / Stojanowski, Christopher (Author) / College of Liberal Arts and Sciences (Contributor)
Created2015-03-27
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Longitudinal Social Networks Impacts on Weight and Weight-Related Behaviors Assessed Using Mobile-Based Ecological Momentary Assessments: Study Protocols for the SPARC Study

Description

Background: The transition from the home to college is a phase in which emerging adults shift toward more unhealthy eating and physical activity patterns, higher body mass indices, thus increasing risk of overweight/obesity. Currently, little is understood about how changing friendship networks shape weight gain behaviors. This paper describes the recruitment,…

Background: The transition from the home to college is a phase in which emerging adults shift toward more unhealthy eating and physical activity patterns, higher body mass indices, thus increasing risk of overweight/obesity. Currently, little is understood about how changing friendship networks shape weight gain behaviors. This paper describes the recruitment, data collection, and data analytic protocols for the SPARC (Social impact of Physical Activity and nutRition in College) study, a longitudinal examination of the mechanisms by which friends and friendship networks influence nutrition and physical activity behaviors and weight gain in the transition to college life.

Methods: The SPARC study aims to follow 1450 university freshmen from a large university over an academic year, collecting data on multiple aspects of friends and friendship networks. Integrating multiple types of data related to student lives, ecological momentary assessments (EMAs) are administered via a cell phone application, devilSPARC. EMAs collected in four 1-week periods (a total of 4 EMA waves) are integrated with linked data from web-based surveys and anthropometric measurements conducted at four times points (for a total of eight data collection periods including EMAs, separated by ~1 month). University databases will provide student card data, allowing integration of both time-dated data on food purchasing, use of physical activity venues, and geographical information system (GIS) locations of these activities relative to other students in their social networks.

Discussion: Findings are intended to guide the development of more effective interventions to enhance behaviors among college students that protect against weight gain during college.
ContributorsBruening, Meg (Author) / Ohri-Vachaspati, Punam (Author) / Brewis, Alexandra (Author) / Laska, Melissa (Author) / Todd, Michael (Author) / Hruschka, Daniel (Author) / Schaefer, David (Author) / Whisner, Corrie (Author) / Dunton, Genevieve (Author) / College of Health Solutions (Contributor)
Created2016-08-30
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How Privilege and Opportunity Are Associated with Psychological Well-being

Description
Ethnic groups experience different societal and economic circumstances that contribute to their well-being. Life satisfaction and happiness are commonly used as a measure of well-being; but they are not often used to evaluate well-being in lower income countries. This study focuses on the self-reported life satisfaction and happiness of members…

Ethnic groups experience different societal and economic circumstances that contribute to their well-being. Life satisfaction and happiness are commonly used as a measure of well-being; but they are not often used to evaluate well-being in lower income countries. This study focuses on the self-reported life satisfaction and happiness of members of ethnic groups from low- and middle-income countries and its correlation with ethnic privilege, gender opportunity, and income. Using two self-reported measures of well-being—life satisfaction and happiness—among 110,391 women in 27 countries (ages 15-49) surveyed in Multiple Indicator Cluster Surveys, this study examines how country-level indicators of gender opportunity, ethnic-level indicators of privilege and household-level measures of wealth are associated with well-being. Our findings indicate a significant relationship between ethnic privilege, gender opportunity and income on life satisfaction. The results from this study provide valuable data and implications for lower income countries to identify and reduce modifiable risk factors that affect a population’s well-being.
ContributorsChavez Lopez, Giselle (Co-author, Co-author) / Hruschka, Daniel (Thesis director) / Gonzales, Angela (Committee member) / School of Molecular Sciences (Contributor) / School of Human Evolution & Social Change (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
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The Importance of Friendship and Community in a Phoenix Homeless Population

Description
The lonely, empty face panhandling on the street corner has a story to tell. At first glance, most people write the homeless off as less than worthy. However, there is a deeper connection and understanding of relationships and a sense of community unseen by the majority of passer-byers. Amidst the…

The lonely, empty face panhandling on the street corner has a story to tell. At first glance, most people write the homeless off as less than worthy. However, there is a deeper connection and understanding of relationships and a sense of community unseen by the majority of passer-byers. Amidst the humdrum beat of every day life, there is toil to find basic necessities such as food, water, sanitation, and a place to rest. At the same time, there is laughter and friendship as they help one another through the hostilities of their circumstances. Combining the creative elements of photojournalism and qualitative interviewing, the basic daily needs and struggles of the homeless will be delved into to answer how friendship is pertinent to survival on the streets.
ContributorsFisher, Meghan (Author) / Hruschka, Daniel (Thesis director) / Hita, Liza (Committee member) / Newland, Judy (Committee member) / Barrett, The Honors College (Contributor) / College of Liberal Arts and Sciences (Contributor)
Created2012-12

The Association of Community Membership and Socioeconomic Status in India with Contraceptive Use

Description
Examining the effect of various factors such as class, gender, and status on health inequalities in India is crucial for improving access to health services. However, most research on castes in India is done using broad, government-defined categories, including “Scheduled Castes,” “Scheduled Tribes,” “Forward Classes,” and “Other Backwards Classes.” These…

Examining the effect of various factors such as class, gender, and status on health inequalities in India is crucial for improving access to health services. However, most research on castes in India is done using broad, government-defined categories, including “Scheduled Castes,” “Scheduled Tribes,” “Forward Classes,” and “Other Backwards Classes.” These general categories erase the experiences that more specific caste groups have in their health and their livelihood. Using the 2015-2016 Demographic and Health Survey of India, this study analyzes data on 699,686 women aged 15-49 to investigate the association of socioeconomic status, assessed by wealth, education, and community status on two types of contraceptive use–sterilization and other modern methods. Those with secondary education or higher were much less likely to be sterilized and more likely to use non-sterilization forms of modern contraception. Interestingly, those with greater household wealth were more likely to be sterilized but had no different chance of using non-sterilization forms of modern contraception. After controlling for other socioeconomic factors, members of Scheduled Castes and Backward Classes are more likely to be sterilized. However, there was additional heterogeneity between groups, with Muslim groups and Northeastern tribes much less likely to be sterilized, and Southern tribes more likely to be sterilized. Moreover, Muslim groups as well as Northern and Northeastern tribes were more likely to use non-sterilizations forms of contraception, whereas Southern tribes were less likely to use non-sterilization forms of contraception. These findings illustrate that in addition to differences by major caste categories, there is still religious and regional variation in the likelihood of using different forms of contraception. Future research should examine how unique community factors erased within the already present government caste system can affect health. In addition, more research should be done on the various effects of discrimination faced by these communities and how this discrimination affects their health education, access, and autonomy.
ContributorsChandra, Natasha (Author) / Hruschka, Daniel (Thesis director) / Drake, Alexandria (Committee member) / Barrett, The Honors College (Contributor) / School of Human Evolution & Social Change (Contributor) / School of International Letters and Cultures (Contributor) / Dean, W.P. Carey School of Business (Contributor)
Created2024-05