Computational Engineering Commons^™

Improving Feature Learning Capability And Interpretability Of Unsupervised Neural Networks, Chathurika S. Wickramasinghe Brahmana

Theses and Dissertations

The motivation for this dissertation is two-prong. Firstly, the current state of machine learning imposes the need for unsupervised Machine Learning (ML). Secondly, once such models are developed, a deeper understanding of ML models is necessary for humans to adapt and use such models.

Real-world systems generate massive amounts of unlabeled data at rapid speed, limiting the usability of state-of-the-art supervised machine learning approaches. Further, the manual labeling process is expensive, time-consuming, and requires the expertise of the data. Therefore, the existing supervised learning algorithms are unable to take advantage of the abundance of real-world unlabeled data. Thus, relying on …

Preference-Aware Task Assignment In Mobile Crowdsensing, Fatih Yucel

Theses and Dissertations

Mobile crowdsensing (MCS) is an emerging form of crowdsourcing, which facilitates the sensing data collection with the help of mobile participants (workers). A central problem in MCS is the assignment of sensing tasks to workers. Existing work in the field mostly seek a system-level optimization of task assignments (e.g., maximize the number of completed tasks, minimize the total distance traveled by workers) without considering individual preferences of task requesters and workers. However, users may be reluctant to participate in MCS campaigns that disregard their preferences. In this dissertation, we argue that user preferences should be a primary concern in the …

Computational Analysis And Prediction Of Intrinsic Disorder And Intrinsic Disorder Functions In Proteins, Akila I. Katuwawala

Theses and Dissertations

COMPUTATIONAL ANALYSIS AND PREDICTION OF INTRINSIC DISORDER AND INTRINSIC DISORDER FUNCTIONS IN PROTEINS

By Akila Imesha Katuwawala

A dissertation submitted in partial fulfillment of the requirements for the degree of Engineering, Doctor of Philosophy with a concentration in Computer Science at Virginia Commonwealth University.

Virginia Commonwealth University, 2021

Director: Lukasz Kurgan, Professor, Department of Computer Science

Proteins, as a fundamental class of biomolecules, have been studied from various perspectives over the past two centuries. The traditional notion is that proteins require fixed and stable three-dimensional structures to carry out biological functions. However, there is mounting evidence regarding a “special” class …

Systematic Model-Based Design Assurance And Property-Based Fault Injection For Safety Critical Digital Systems, Athira Varma Jayakumar

Theses and Dissertations

With advances in sensing, wireless communications, computing, control, and automation technologies, we are witnessing the rapid uptake of Cyber-Physical Systems across many applications including connected vehicles, healthcare, energy, manufacturing, smart homes etc. Many of these applications are safety-critical in nature and they depend on the correct and safe execution of software and hardware that are intrinsically subject to faults. These faults can be design faults (Software Faults, Specification faults, etc.) or physically occurring faults (hardware failures, Single-event-upsets, etc.). Both types of faults must be addressed during the design and development of these critical systems. Several safety-critical industries have widely adopted …

Adhesion At Solid/Liquid Interfaces, Neda Ojaghlou

Theses and Dissertations

The adhesion at solid/liquid interface plays a fundamental role in diverse fields and helps explain the structure and physical properties of interfaces, at the atomic scale, for example in catalysis, crystal growth, lubrication, electrochemistry, colloidal system, and in many biological reactions. Unraveling the atomic structure at the solid/liquid interface is, therefore, one of the major challenges facing the surface science today to understand the physical processes in the phenomena such as surface coating, self-cleaning, and oil recovery applications. In this thesis, a variety of theory/computational methods in statistical physics and statistical mechanics are used to improve understanding of water adhesion …

Mechanochemical Regulation Of Epithelial Tissue Remodeling: A Multiscale Computational Model Of The Epithelial-Mesenchymal Transition Program, Lewis Scott

Theses and Dissertations

Epithelial-mesenchymal transition (EMT) regulates the cellular processes of migration, growth, and proliferation - as well as the collective cellular process of tissue remodeling - in response to mechanical and chemical stimuli in the cellular microenvironment. Cells of the epithelium form cell-cell junctions with adjacent cells to function as a barrier between the body and its environment. By distributing localized stress throughout the tissue, this mechanical coupling between cells maintains tensional homeostasis in epithelial tissue structures and provides positional information for regulating cellular processes. Whereas in vitro and in vivo models fail to capture the complex interconnectedness of EMT-associated signaling networks, …

Investigating Smoke Exposure And Chronic Obstructive Pulmonary Disease (Copd) With A Calibrated Agent Based Model (Abm) Of In Vitro Fibroblast Wound Healing., James A. Ratti

Theses and Dissertations

COPD is characterized by tissue inflammation and impaired remodeling that suggests fibroblast maintenance of structural homeostasis is dysregulated. Thus, we performed in vitro wound healing experiments on normal and diseased human lung fibroblasts and developed an ABM of fibroblasts closing a scratched monolayer using NetLogo to evaluate differences due to COPD or cigarette smoke condensate exposure. This ABM consists of a rule-set governing the healing response, accounting for cell migration, proliferation, death, activation and senescence rates; along with the effects of heterogeneous activation, phenotypic changes, serum deprivation and exposure to cigarette smoke condensate or bFGF. Simulations were performed to calibrate …

Modeling Time-Dependent Performance Of Submerged Superhydrophobic Or Slippery Surfaces, Ahmed A. Hemeda

Theses and Dissertations

The goal of this study is to quantify the transient performance of microfabricated superhydrophobic surfaces when used in underwater applications. A mathematical framework is developed and used to predict the stability, longevity, and drag reduction benefits of submerged superhydrophobic surfaces with two- or three-dimensional micro-textures. In addition, a novel design is proposed to improve the drag-reduction benefits of lubricant-infused surfaces, by placing a layer of trapped air underneath the lubricant layer. The new design is referred to as lubricant–infused surfaces with trapped air, and it is designed to eliminate the long-lasting longevity problem of submerged superhydrophobic surfaces. The effectiveness of …

Growth And Characterization Of Wide Bandgap Quaternary Bemgzno Thin Films And Bemgzno/Zno Heterostructures, Mykyta Toporkov

Theses and Dissertations

This thesis reports a comprehensive study of quaternary BeMgZnO alloy and BeMgZnO/ZnO heterostructures for UV-optoelectronics electronic applications. It was shown that by tuning Be and Mg contents in the heterostructures, high carrier densities of two-dimensional electron gas (2DEG) are achievable and makes its use possible for high power RF applications. Additionally, optical bandgaps as high as 5.1 eV were achieved for single crystal wurtzite material which allows the use of the alloy for solar blind optoelectronics (E_g>4.5eV) or intersubband devices.

A systematic experimental and theoretical study of lattice parameters and bandgaps of quaternary BeMgZnO alloy was performed for …

Evaluation Of Tcp Header Fields For Data Overhead Efficiency, Justin K. Yirka

Undergraduate Research Posters

Bandwidth across the internet is constricted by monetary factors and hardware development, so researchers are left to improve the efficiency of data transmitted in order to improve internet speeds. The transmission control protocol (TCP) is the primary transport protocol on the modern internet, ensuring reliable delivery of the majority of data transmitted. I evaluated the TCP header fields for efficient use of data overhead so as to determine current waste and to suggest possible areas for revision. I examined original specifications for TCP mechanisms, comparing them to modern implementations as determined by updated standards and modern practices in the networking …