Statistics and Probability Commons^™

Optical Modeling For A Laser Phased-Array Directed Energy System, Gary B. Hughes, Philip Lubin, Janelle Griswold, Brianna Cook, Durante Bozzini, Hugh O'Neill, Peter Meinhold, Jonathan Suen, J Bible, Jordan Riley, Isabella E. Johansson, Mark Pryor, Miikka Kangas

Statistics

We present results of optical simulations for a laser phased array directed energy system. The laser array consists of individual optical elements in a square or hexagonal array. In a multi-element array, the far-field beam pattern depends on both mechanical pointing stability and on phase relationships between individual elements. The simulation incorporates realistic pointing and phase errors. Pointing error components include systematic offsets to simulate manufacturing and assembly variations. Pointing also includes time-varying errors that simulate structural vibrations, informed from random vibration analysis of the mechanical design. Phase errors include systematic offsets, and time-varying errors due to both mechanical vibration …

Incidence And Trends Of Blastomycosis-Associated Hospitalizations In The United States, Amy E. Seitz, Naji Younes, Claudia A. Steiner, Rebecca Prevots

Epidemiology Faculty Publications

We used the State Inpatient Databases from the United States Agency for Healthcare Research and Quality to provide state-specific age-adjusted blastomycosis-associated hospitalization incidence throughout the entire United States. Among the 46 states studied, states within the Mississippi and Ohio River valleys had the highest age-adjusted hospitalization incidence. Specifically, Wisconsin had the highest age-adjusted hospitalization incidence (2.9 hospitalizations per 100,000 person-years). Trends were studied in the five highest hospitalization incidence states. From 2000 to 2011, blastomycosis-associated hospitalizations increased significantly in Illinois and Kentucky with an average annual increase of 4.4% and 8.4%, respectively. Trends varied significantly by state. Overall, 64% of …

Mixtures Of Self-Modelling Regressions, Rhonda D. Szczesniak, Kert Viele, Robin L. Cooper

Statistics Faculty Publications

A shape invariant model for functions f₁,...,f_n specifies that each individual function f_i can be related to a common shape function g through the relation f_i(x) = a_ig(c_ix + d_i) + b_i. We consider a flexible mixture model that allows multiple shape functions g₁,...,g_K, where each f_i is a shape invariant transformation of one of those g_K. We derive an MCMC algorithm for fitting the model using Bayesian Adaptive Regression Splines (BARS), propose …

Mathematical Modeling Of Tick-Borne Encephalitis In Humans, Amanda Kriesel, Michael Meyer, Geoffrey Peterson

Journal of Undergraduate Research at Minnesota State University, Mankato

Tick-Borne Encephalitis is a virus that affects ones nervous system and is transmitted from tick to human through tick bite. In recent years, the number of cases of tick-borne encephalitis in Europe has been increasing. This mathematical biological model of Tick-Borne Encephalitis was created in order to further our understanding of such phenomenon, as well as study the relationship between vectors and their hosts. Specifically, we will investigate the population model of ticks in certain regions and its correlation to tick-borne encephalitis infections in the region.

Choosing Between Parametric And Non-Parametric Tests, Russ Johnson

Journal of Undergraduate Research at Minnesota State University, Mankato

A common question in comparing two sets of measurements is whether to use a parametric testing procedure or a non-parametric procedure. The question is even more important in dealing with smaller samples. Here, using simulation, several parametric and nonparametric tests, such as, t-test, Normal test, Wilcoxon Rank Sum test, van-der Waerden Score test, and Exponential Score test are compared.

Modeling Student Engagement In The Classroom, Sarah Painter

Journal of Undergraduate Research at Minnesota State University, Mankato

Connections to Community is a multi-institutional study that looks at the influence of community on post-secondary, science and engineering students and their engagement in academic activity. This paper focuses specifically on student engagement within the classroom as a follow-up to a previous paper by Wendy Hoffman, Identifying Influential Variables of Student Academic Engagement (Hoffman, 2013). The goal of this work is to model student engagement in the classroom using classroom observation data that has been cleaned and then compare the results with those found in Hoffman’s paper which used pre-cleaning data. The cleaned data is used to create two data …

The Structure Of Child And Adolescent Aggression: Confirmatory Factor Analysis Of A Brief Peer Conflict Scale, Justin Russell

LSU New Orleans Theses and Dissertations

The importance of simultaneous consideration of forms and functions in youth measures of aggressive behavior is well established. Competing models have presented these highly interrelated constructs as either independent (e.g., reactive or overt) or paired factors (e.g., reactive and overt). The current study examines these models in the context of assessing the viability of a new self-report measure, the Peer Conflict Scale – 20 Item Version. Confirmatory factor analyses were conducted on PCS 20 responses from 1,048 school-age youth living in the Gulf Coast region. Both models significantly improved upon one or two-factor alternatives, and demonstrated partial invariance across gender …

Herd Immunity And The Necessity Of Vaccinations: Modeling The Effects Of Mmr Vaccinations, Caitlyn Cardetti, Katie Groskreutz, Melissa Zins

Journal of Undergraduate Research at Minnesota State University, Mankato

The MMR vaccination is a two dose vaccine given to children between the ages of 12 – 15 months and the second dose between the ages of 4 – 6 years to prevent measles, mumps, and rubella. The objective was to mathematically model the effects of the MMR vaccinations in a hypothetical school through multiple compartment and spatial models. These models were based on each disease individually with their respective vaccine effectiveness and disease infection rates. These models demonstrated the limits of herd immunity. Herd immunity occurs when a high enough percentage of the population is immune or vaccinated to …

Coexistence Of Multi-Allelic Polymorphism With Migration And Selection, Andrew Flick

Journal of Undergraduate Research at Minnesota State University, Mankato

Population ecology is concerned with the growth patterns of populations. This field has many applications, ranging from survival at the environmental level, to the spread of infectious diseases at the cellular level. Mathematical modeling and computer simulation can be powerful tools in researching this area. I will be investigating the spatial patterns in populations (or gene frequencies) due to migration and selection. My research conditions are for the maintenance of polymorphism under a variety of migration schemes in discrete-space and continuous-time mathematical models. The results will be applicable from the ecological level to the molecular level. Some species are better …

Statistical Models Of Self-Efficacy In Stem Students, Sarah Painter

Journal of Undergraduate Research at Minnesota State University, Mankato

Persistence through undergraduate education may be explained by self-efficacy. It is the belief in one’s self to persevere through challenges. Bandura stated four areas that are thought to influence self-efficacy: mastery experience, social persuasion, vicarious experience, and physiological state. In this study, we focused on general and academic self-efficacy in STEM students, in the hopes of learning more about the relationships between Bandura’s categories, demographics, and self-efficacy. Data was taken from two institutions: one, a large research focused university, and the other, a smaller teaching focused university. In the first phase, surveys on general self-efficacy were taken at both institutions …

Instrumental Variable Estimation In A Survival Context, Eric J. Tchetgen Tchetgen, Stefan Walter, Stijn Vansteelandt, Torben Martinussen, Maria Glymour

Harvard University Biostatistics Working Paper Series

No abstract provided.

Non- And Semi-Parametric Bayesian Inference With Recurrent Events And Coherent Systems Data, A. K. M. Fazlur Rahman

Theses and Dissertations

This dissertation deals with non- and semi-parametric Bayesian inference of gap-time distribution with recurrent event data and simultaneous inference of component and system reliabilities of coherent systems data. Recurrent event data arise from a wide variety of studies/fields such as clinical trials, epidemiology, public health, biomedicine (e.g. repeated heart attack, repeated tumor occurrences of a cancer patient). In Chapter 2 we develop nonparametric Bayes and empirical Bayes estimators of the survivor function \bar{F} = 1 - F, of the gap-time distribution by assigning a Dirichlet process prior on F. We develop a closed form estimator of \bar{F} as well as …

Spatiotemporal Crime Analysis, James Q. Tay, Abish Malik, Sherry Towers, David Ebert

The Summer Undergraduate Research Fellowship (SURF) Symposium

There has been a rise in the use of visual analytic techniques to create interactive predictive environments in a range of different applications. These tools help the user sift through massive amounts of data, presenting most useful results in a visual context and enabling the person to rapidly form proactive strategies. In this paper, we present one such visual analytic environment that uses historical crime data to predict future occurrences of crimes, both geographically and temporally. Due to the complexity of this analysis, it is necessary to find an appropriate statistical method for correlative analysis of spatiotemporal data, as well …

Likelihood Based Estimation Of Logistic Structural Nested Mean Models With An Instrumental Variable, Roland A. Matsouaka, Eric J. Tchetgen Tchetgen

Harvard University Biostatistics Working Paper Series

No abstract provided.

Using Remote Sensing Data To Predict The Spread Of Mosquito Borne Disease, Mary Ellen O'Donnell, Erika Podest

STAR Program Research Presentations

There is interest in how environmental variables derived from satellite data such as temperature, vegetation cover, and precipitation correlate to vector borne disease occurrence such as malaria and dengue fever. This study will be carried out using a decision tree based open source software called Random Forests to find correlations between the remote sensing variables and mosquito abundance. Software will be written in C# to take large amounts of data from the NASA satellite database and automatically format it for the Random Forest Software input. Correlations found, using Random Forests, between disease incidence and the variables can be used as …

The Path To The Sea: Leatherback Hatchling Orientation At Sandy Point National Wildlife Refuge, Christina Macmillan, Kelly Stewart

STAR Program Research Presentations

Once sea turtle hatchlings emerge from their nest, they must find their way to the ocean by using cues such as a bright horizon and the slope of the beach. While moving toward the water, hatchlings often must navigate past predators and through vegetation, sticks, footprints in the sand, and other dangers such as ghost crab holes. Sometimes hatchlings become confused (or disoriented) and turn in circles to find the right route to the water. Sea turtle hatchlings also may become disoriented as a result of human impacts such as town lights or trash. The purpose of our experiment was …

Light Pollution Research Through Citizen Science, John Kanemoto

STAR Program Research Presentations

Light pollution (LP) can disrupt and/or degrade the health of all living things, as well as, their environments. The goal of my research at the NOAO was to check the accuracy of the citizen science LP reporting systems entitled: Globe at Night (GaN), Dark Sky Meter (DSM), and Loss of the Night (LoN). On the GaN webpage, the darkness of the night sky (DotNS) is reported by selecting a magnitude chart. Each magnitude chart has a different density/number of stars around a specific constellation. The greater number of stars implies a darker night sky. Within the DSM iPhone application, a …

Tuffoam Density Variation Through Radiography, Sergio Contreras Esquivel

STAR Program Research Presentations

TufFoam is a low density, high impact tolerant polyurethane foam with good high voltage breakdown developed at the Sandia National Laboratories. Identically shaped samples have been produced with various formulations and production conditions. Eight different variables were studied. Our aim is to compare the density variation of the material when produced and processed under distinct conditions. The density of TufFoam is determined using radiographic imaging. We extract the foam density by fitting the radiographic density of each step in a plastic step wedge with 10 steps from 0.1 to 1.0 inches and applying the resulting equation to convert each pixel …

Lifestyle And Metformin Interventions Have A Durable Effect To Lower Crp And Tpa Levels In The Diabetes Prevention Program Except In Those Who Develop Diabetes., Ronald B Goldberg, Marinella G Temprosa, Kieren J Mather, Trevor J Orchard, Abbas E Kitabchi, Karol E Watson

GW Biostatistics Center

OBJECTIVE: We evaluate whether lifestyle and metformin interventions used to prevent diabetes have durable effects on markers of inflammation and coagulation and whether the effects are influenced by the development of diabetes.

RESEARCH DESIGN AND METHODS: The Diabetes Prevention Program was a controlled clinical trial of 3,234 subjects at high risk for diabetes who were randomized to lifestyle, metformin, or placebo interventions for 3.4 years. Diabetes was diagnosed semiannually by fasting glucose and annually by oral glucose tolerance testing. In addition to baseline testing, anthropometry was performed every 6 months; fasting insulin yearly; and hs-CRP, tissue plasminogen activator (tPA), and …

Inflammatory Breast Cancer Clusters: A Hypothesis, Paul H. Levine, Salman Hashmi, Ashley A. Minaei, Carmela Veneroso

Epidemiology Faculty Publications

Reproduced with permission of Baishideng Publishing Group, World Journal of Clinical Oncology.

Quantile Regression For Climate Data, Dilhani Marasinghe

All Theses

Quantile regression is a developing statistical tool which is used to explain the relationship between response and predictor variables. This thesis describes two examples of climatology using quantile regression.Our main goal is to estimate derivatives of a conditional mean and/or conditional quantile function. We introduce a method to handle autocorrelation in the framework of quantile regression and used it with the temperature data. Also we explain some properties of the tornado data which is non-normally distributed. Even though quantile regression provides a more comprehensive view, when talking about residuals with the normality and the constant variance assumption, we would prefer …

Asymptotic Behavior Of Finite-Time Ruin Probability In A By-Claim Risk Model With Constant Interest Rate, Lei Wang

Master's Theses

Enlightened by the results of Li [8] and Wang [19], we study the ruin probability of a renewal risk model with constant interest rate and by-claim parts. We assume that the claim size and the inter-arrival time satisfy a certain dependent structure with some additional assumptions on their distribution functions. Furthermore, we give relevant preparation of theory and compare several existing risk models and dependent structures. In this way, we present our result and prove it.

General Approaches For Combining Multiple Rare Variant Associate Tests Provide Improved Power Across A Wider Range Of Genetic Architecture, Nathan L. Tintle, Brian Greco, Allison Hainline, Keli Liu, Jaron Arbet, Alejandra Benitez, Kelsey Grinde

Faculty Work Comprehensive List

In the wake of the widespread availability of genome sequencing data made possible by way of nextgeneration technologies, a flood of gene‐based rare variant tests have been proposed. Most methods claim superior power against particular genetic architectures. However, an important practical issue remains for the applied researcher—namely, which test should be used for a particular association study which may consider multiple genes and/or multiple phenotypes. Recently, tests have been proposed which combine individual tests to minimize power loss while improving the robustness to a wide range of genetic architectures. In our analysis, we propose an expansion of these approaches, by …

Visualizing And Forecasting Box-Office Revenues: A Case Study Of The James Bond Movie Series, Vahan Petrosyan

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

This Master's report deals with the visualization and forecasting of the box-office revenues and some related variables from the James Bond movie Series. Visualization techniques such as time series plots, scatterplot matrices, dotplots, boxplots, histograms, normal quantile plots, parallel coordinates plots, heatmaps, mosaic plots, association plots, and choropleth maps are used to provide some deeper insights into the given dataset. Additionally, the results from an article published in 1997 are reproduced and extended. This article modeled the box-office revenues of the James Bond movie series. Numerous statistical models were examined to obtain the models that are closest to the original …

Penalized Regressions For Variable Selection Model, Single Index Model And An Analysis Of Mass Spectrometry Data., Yubing Wan

Electronic Theses and Dissertations

The focus of this dissertation is to develop statistical methods, under the framework of penalized regressions, to handle three different problems. The first research topic is to address missing data problem for variable selection models including elastic net (ENet) method and sparse partial least squares (SPLS). I proposed a multiple imputation (MI) based weighted ENet (MI-WENet) method based on the stacked MI data and a weighting scheme for each observation. Numerical simulations were implemented to examine the performance of the MIWENet method, and compare it with competing alternatives. I then applied the MI-WENet method to examine the predictors for the …

Genetic Predictors Of Metabolic Side Effects Of Diuretic Therapy, Jorge L. Del Aguila

Dissertations and Theses (Open Access)

Thiazide diuretics are a recommended first-line monotherapy for hypertension (i.e.SBP>140 mmHg or DBP>90 mmHg). Even so, diuretics are associated with adverse metabolic side effects, such as hyperlipidemia, hyperglycemia and hypokalemia which increase the risk of developing type II diabetes. This thesis used three analytical strategies to identify and quantify genetic factors that contribute to the development of adverse metabolic effects due to thiazide diuretic treatment. I performed a genome-wide association study (GWAS) and meta-analysis of the change in fasting plasma glucose and triglycerides in response to HCTZ from two different clinical trials: the Pharmacogenomic Evaluation of Antihypertensive Responses …

Convergence Of A Reinforcement Learning Algorithm In Continuous Domains, Stephen Carden

All Dissertations

In the field of Reinforcement Learning, Markov Decision Processes with a finite number of states and actions have been well studied, and there exist algorithms capable of producing a sequence of policies which converge to an optimal policy with probability one. Convergence guarantees for problems with continuous states also exist. Until recently, no online algorithm for continuous states and continuous actions has been proven to produce optimal policies. This Dissertation contains the results of research into reinforcement learning algorithms for problems in which both the state and action spaces are continuous. The problems to be solved are introduced formally as …

Analyses Of 2002-2013 China’S Stock Market Using The Shared Frailty Model, Chao Tang

Electronic Theses and Dissertations

This thesis adopts a survival model to analyze China’s stock market. The data used are the capitalization-weighted stock market index (CSI 300) and the 300 stocks for creating the index. We define the recurrent events using the daily return of the selected stocks and the index. A shared frailty model which incorporates the random effects is then used for analyses since the survival times of individual stocks are correlated. Maximization of penalized likelihood is presented to estimate the parameters in the model. The covariates are selected using the Akaike information criterion (AIC) and the variance inflation factor (VIF) to avoid …

A Study Of Joinpoint Models For Longitudinal Data, Libo Zhou

UNLV Theses, Dissertations, Professional Papers, and Capstones

In many medical studies, data are collected simultaneously on multiple biomarkers from each individual. Levels of these biomarkers are measured periodically over certain time duration, giving rise to longitudinal trajectories. The subjects under study may also be subject to dropout due to several competing causes, the likelihood of which may be affected by the levels of these biomarkers. In this dissertation, we investigate flexible Bayesian modeling of such data, taking into account any available covariate information as well as possible censoring of the drop-out times. We propose joint models for multiple biomarkers with multiple causes of dropout. Our proposed models …

Comparison Of Hazard, Odds And Risk Ratio In The Two-Sample Survival Problem, Benedict P. Dormitorio

Dissertations

Cox proportional hazards is the standard method for analyzing treatment efficacy when time-to-event data is available. In the absence of time-to-event, investigators may use logistic regression which only requires relative frequencies of events, or Poisson regression which requires only interval-summarized frequency tables of time-to-event. When event frequencies are used instead of time-to-events, does it always result in a loss in power?

We investigate the relative performance of the three methods. In particular, we compare the power of tests based on the respective effect-size estimates (1)hazard ratio (HR), (2)odds ratio (OR), and (3)risk ratio (RR). We use a variety of survival …