Physical Sciences and Mathematics Commons^™

Multimodal Data Fusion And Attack Detection In Recommender Systems, Mehmet Aktukmak

USF Tampa Graduate Theses and Dissertations

The commercial platforms that use recommender systems can collect relevant information to produce useful recommendations to the platform users. However, these sources usually contain missing values, imbalanced and heterogeneous data, and noisy observations. Such characteristics render the process of exploiting the information nontrivial, as one should carefully address them during the data fusion process. In addition to the degenerative characteristics, some entries can be fake, i.e., they can be the outcomes of malicious intents to manipulate the system. These entries should be eliminated before incorporation to any recommendation task. Detecting such malicious attacks quickly and accurately and then mitigating them …

Numerical Study Of Gap Distributions In Determinantal Point Process On Low Dimensional Spheres: L-Ensemble Of O(N) Model Type For N = 2 And N = 3, Xiankui Yang

USF Tampa Graduate Theses and Dissertations

Poisson point process is the most well-known point process with many applications. Unlike Poisson point process, which is the random set of non-intersecting points, determinantal point process refers to certain class of point processes where the points tend to interact with each other. The interaction often leads to more uniformly distributed points compared to those in Poisson point process.

In this article, we study the gap distribution of certain class of determinantal point process, L-ensemble of O(n) model type, and compare the distribution with the ones from the other known determinantal point process that appears in random matrices. Our numerical …

Bayesian Reliability Analysis For Optical Media Using Accelerated Degradation Test Data, Kun Bu

USF Tampa Graduate Theses and Dissertations

ISO (the International Organization for Standardization) 10995:2011 is the inter-national standard providing guidelines for assessing the reliability and service life of optical media, which is designed to be highly reliable and possesses a long lifetime. A well-known challenge of reliability analysis for highly reliable devices is that it is hard to obtain sufficient failure data under their normal use conditions. Accelerated degradation tests (ADTs) are commonly used to quickly obtain physical degradation data under elevated stress conditions, which are then extrapolated to predict reliability under the normal use condition. This standard achieves the estimation of the lifetime of recordable media, …

Identification Of Patterns And Disruptions In Ambient Sensor Data From Private Homes, Yan Wang

USF Tampa Graduate Theses and Dissertations

The world’s population is rapidly aging and the increasing demand for home and health care services from this aging population brings unprecedented challenges to the economy and society. Ambient-assisted smart homes, residences equipped with ambient sensors to monitor the resident’s daily activities in a continuous and unobtrusive way, present great potential to manage the growing care service needs of this older population segment, and enable them to age-in-place.

Despite growing research, using ambient sensor data from private homes to monitor daily activities, health and wellness still faces significant challenges. To study ambient sensor data from private homes where annotated data …

Predictive Validity Of Standards-Based And Curriculum-Embedded Assessments For Predicting Readiness At Kindergarten Entry, Elizabeth Ashton Decamilla

USF Tampa Graduate Theses and Dissertations

As with traditional K-12 educational settings, early childhood assessments have been a primary source of information determining whether early educational experiences have promoted children’s readiness to start school in kindergarten. The level of use of Kindergarten Entry Assessments (KEAs) has become more wide-spread to establish levels of school readiness at kindergarten entry.

This quantitative, correlational study of children in schools that have blended Head Start/Voluntary Prekindergarten funded programs examined the predictive relationships between the independent variables (i.e., VPK Assessments and Teaching Strategies GOLD) and the dependent variable of kindergarten readiness, as measured by the Work Sampling System™ (WSS). Additionally, the …

Exploration Of Factors Associated With Perceptions Of Community Safety Among Youth In Hillsborough County, Florida: A Convergent Parallel Mixed-Methods Approach, Yingwei Yang

USF Tampa Graduate Theses and Dissertations

Introduction: Youth perceived safety is not only linked to crime and violence in a neighborhood but is also associated with health risk behaviors and certain neighborhood characteristics. The purpose of this mixed-methods study was to measure the co-occurring effects of individual and community risk factors by conducting a secondary data analysis using structural equation modeling (SEM) and to explore reasons for youth feeling safe/unsafe in their community using photovoice methodology.

Methods: Syndemic theory/model served as the theoretical framework to guide this mixed-methods study with a convergent parallel design. The quantitative strand (first manuscript) utilized an existing dataset collected from middle …

Bayesian Reliability Analysis Of The Power Law Process And Statistical Modeling Of Computer And Network Vulnerabilities With Cybersecurity Application, Freeh N. Alenezi

USF Tampa Graduate Theses and Dissertations

As most of mankind now lives in an era of high dependence on multiple technologies and complex systems to store and manage sensitive information, researchers are constantly urged to obtain and improve measurements and methodologies that have the ability to evaluate systems reliability and security. The objectives of the present dissertation are to improve the Bayesian reliability estimation of a software package where the Power Law Process, also known as Non-Homogeneous Poisson Process, is the underlying failure model and to develop a set of statistical models evaluating computer operating systems vulnerabilities. Furthermore, we develop a reliability function of a computer …

Gradient Boosting For Survival Analysis With Applications In Oncology, Nam Phuong Nguyen

USF Tampa Graduate Theses and Dissertations

Cancer is one of the most deadly diseases that the world has been fighting against over decades. An enormous number of research has been conducted, via a wide scale of approaches, raging from genetic analysis to mathematical modeling. Survival analysis is a well-performed methodology frequently used to estimate the survival probability of a patient. Although there has been a large number of methods for survival analysis, efficient exploration of a high-dimensional feature space has been challenging due to its computational cost and complexity. This thesis adapts the component-wise gradient boosting algorithms for cancer survival analysis, and also proposes a new …