Physical Sciences and Mathematics Commons^™

Applications Of Sampling And Estimation On Networks, Fabricio Murai Ferreira

Doctoral Dissertations

Networks or graphs are fundamental abstractions that allow us to study many important real systems, such as the Web, social networks and scientific collaboration. It is impossible to completely understand these systems and answer fundamental questions related to them without considering the way their components are connected, i.e., their topology. However, topology is not the only relevant aspect of networks. Nodes often have information associated with them, which can be regarded as node attributes or labels. An important problem is then how to characterize a network w.r.t. topology and node label distributions. Another important problem is how to design efficient …

Intrinsic Functions For Securing Cmos Computation: Variability, Modeling And Noise Sensitivity, Xiaolin Xu

Doctoral Dissertations

A basic premise behind modern secure computation is the demand for lightweight cryptographic primitives, like identifier or key generator. From a circuit perspective, the development of cryptographic modules has also been driven by the aggressive scalability of complementary metal-oxide-semiconductor (CMOS) technology. While advancing into nano-meter regime, one significant characteristic of today's CMOS design is the random nature of process variability, which limits the nominal circuit design. With the continuous scaling of CMOS technology, instead of mitigating the physical variability, leveraging such properties becomes a promising way. One of the famous products adhering to this double-edged sword philosophy is the Physically …

Stochastic Network Design: Models And Scalable Algorithms, Xiaojian Wu

Doctoral Dissertations

Many natural and social phenomena occur in networks. Examples include the spread of information, ideas, and opinions through a social network, the propagation of an infectious disease among people, and the spread of species within an interconnected habitat network. The ability to modify a phenomenon towards some desired outcomes has widely recognized benefits to our society and the economy. The outcome of a phenomenon is largely determined by the topology or properties of its underlying network. A decision maker can take management actions to modify a network and, therefore, change the outcome of the phenomenon. A management action is an …

Identifying Examinees Who Possess Distinct And Reliable Subscores When Added Value Is Lacking For The Total Sample, Joseph A. Rios

Doctoral Dissertations

Research has demonstrated that although subdomain information may provide no added value beyond the total score, in some contexts such information is of utility to particular demographic subgroups (Sinharay & Haberman, 2014). However, it is argued that the utility of reporting subscores for an individual should not be based on one’s manifest characteristics (e.g., gender or ethnicity), but rather on individual needs for diagnostic information, which is driven by multidimensionality in subdomain scores. To improve the validity of diagnostic information, this study proposed the use of Mahalanobis Distance and H^T indices to assess whether an individual’s data significantly departs …

A Comparison Of Techniques For Handling Missing Data In Longitudinal Studies, Alexander R. Bogdan

Masters Theses

Missing data are a common problem in virtually all epidemiological research, especially when conducting longitudinal studies. In these settings, clinicians may collect biological samples to analyze changes in biomarkers, which often do not conform to parametric distributions and may be censored due to limits of detection. Using complete data from the BioCycle Study (2005-2007), which followed 259 premenopausal women over two menstrual cycles, we compared four techniques for handling missing biomarker data with non-Normal distributions. We imposed increasing degrees of missing data on two non-Normally distributed biomarkers under conditions of missing completely at random, missing at random, and missing not …

Sleep Patterns, Urinary Levels Of Melatonin And Subsequent Weight Change In The Women’S Health Initiative Observational Study, Nicole M. Barron

Masters Theses

Results from prospective studies examining associations between sleep duration and weight gain have been mixed. Melatonin has been hypothesized to mediate the association between sleep duration and weight/body composition. In cross-sectional studies, aMT6s has been shown to be inversely associated with weight/body fat percentage. We examined associations between baseline sleep duration, insomnia status, aMT6s levels with weight/body fat percentage through 6 years, utilizing a subset 690 women who participated in a breast cancer case-control study nested within the WHI-OS. Multi-variable and mixed-effects regression was used to calculate beta-coefficients and 95% confidence intervals. Cross-sectional analyses showed urinary aMT6s levels were inversely …

Who Is Like Whom? Reclassification And Performance Patterns For Different Groupings Of English Learners, Molly M. Faulkner-Bond

Doctoral Dissertations

Approximately 10 percent of the US K-12 population consists of English learners (ELs), or students who are learning English in addition to academic content in areas like English language arts (ELA) and mathematics. In addition to meeting the same academic content and performance standards set for all students, it is also a goal for ELs to be reclassified – i.e., to master English so that they can shed the EL label and participate in academic settings where English is used without needing special support. Working with a longitudinal cohort of ~28,000 ELs in grades 3 through 8 from one state, …

Periodontitis And Gestational Diabetes Mellitus: A Systematic Review And Meta-Analysis Of Observational Studies, Samuel A. Abariga, Brian W. Whitcomb

Biostatistics and Epidemiology Faculty Publications Series

Background: Gestational diabetes mellitus (GDM) is glucose intolerance with first onset during pregnancy and is associated with serious maternal and fetal complications. The etiology of GDM is not well understood, but systemic inflammation effects on insulin signaling and glucose metabolism is suspected. Periodontal disease is a chronic inflammatory condition that induces local and host immune responses and has been evaluated for a potential role in development of GDM. Results from studies evaluating the association between periodontitis and GDM are mixed. We performed a systematic review and meta-analysis to summarize available data regarding the association between periodontitis and GDM.

Methods: Twelve …

A Gender Perspective On Gambling Clusters In Sweden Using Longitudinal Data, Ulla Romild, Jessika Svensson, Rachel Volberg

Biostatistics and Epidemiology Faculty Publications Series

AIMS - This study describes five groups of gamblers and changes in their gambling involvement and gambling problems over four years with a particular focus on whether gambling problems among men and women develop differently within the five groups. DESIGN - The study sample is a subset of participants from the Swedish Longitudinal Gambling Study (Swelogs). Six different clusters of past-year gambling, based on frequency of participation in the nine most common forms of gambling in Sweden (lotteries, horses, number games, sports games, bingo, poker, slot machines, casino games or TV contests) were identified in Two-Way Cluster Analysis after the …

Maternal Arsenic Exposure And Gestational Diabetes And Glucose Intolerance In The New Hampshire Birth Cohort Study, Shohreh F. Farzan, Anala Gossai, Yu Chen, Lisa Chasan-Taber, Emily Baker, Margaret Karagas

Biostatistics and Epidemiology Faculty Publications Series

Background

Gestational diabetes mellitus (GDM) is a major pregnancy complication with detrimental effects for both mothers and their children. Accumulating evidence has suggested a potential role for arsenic (As) exposure in the development of GDM, but current studies have not assessed As exposure from water, urine or toenail samples.

Methods

We investigated the association between As exposure and risk of glucose intolerance and GDM among 1151 women enrolled in the New Hampshire Birth Cohort Study. Arsenic was measured in home well water and via biomarkers (i.e., maternal urine collected ~24–28 weeks gestation and toenail clippings collected 2 weeks postpartum).

Results …

Evaluating The Performance Of Infectious Disease Forecasts: A Comparison Of Climate-Driven And Seasonal Dengue Forecasts For Mexico, Michael A. Johansson, Nicholas G. Reich, Aditi Hota, John S. Brownstein, Mauricio Santillana

Biostatistics and Epidemiology Faculty Publications Series

Dengue viruses, which infect millions of people per year worldwide, cause large epidemics that strain healthcare systems. Despite diverse efforts to develop forecasting tools including autoregressive time series, climate-driven statistical, and mechanistic biological models, little work has been done to understand the contribution of different components to improved prediction. We developed a framework to assess and compare dengue forecasts produced from different types of models and evaluated the performance of seasonal autoregressive models with and without climate variables for forecasting dengue incidence in Mexico. Climate data did not significantly improve the predictive power of seasonal autoregressive models. Short-term and seasonal …

A Simple Test Of Class-Level Genetics Association Can Reveal Novel Cardiometabolic Trait Loci, Jing Qian, Sara Nunez, Eric Reed, Muredach P. Reilly, Andrea S. Foulkes

Biostatistics and Epidemiology Faculty Publications Series

Background

Characterizing the genetic determinants of complex diseases can be further augmented by incorporating knowledge of underlying structure or classifications of the genome, such as newly developed mappings of protein-coding genes, epigenetic marks, enhancer elements and non-coding RNAs.

Methods

We apply a simple class-level testing framework, termed Genetic Class Association Testing (GenCAT), to identify protein-coding gene association with 14 cardiometabolic (CMD) related traits across 6 publicly available genome wide association (GWA) meta-analysis data resources. GenCAT uses SNP-level meta-analysis test statistics across all SNPs within a class of elements, as well as the size of the class and its unique correlation …