Physical Sciences and Mathematics Commons^™

Using Delay-Differential Equations For Modeling Calcium Cycling In Cardiac Myocytes, Ryan Thompson

Theses

The cycling of calcium at the intracellular level of cardiac cells plays a key role in the excitation-contraction process. The interplay between ionic currents, buffering agents, and calcium release from the sarcoplasmic reticulum (SR) is a complex system that has been shown experimentally to exhibit complex dynamics including period-2 states (alternans) and higher-order rhythms. Many of the calcium cycling activities involve the sensing, binding, or diffusion of calcium between intracellular compartments; these are physical processes that take time and typically are modeled by “relaxation” equations where the steady-state value and time course of a particular variable are specified through an …

Stability And Entanglement In An Optomechanical System, Matthew Schumacher

Theses

Optomechanical systems are currently of great interest as they lie at the boundary between quantum and classical mechanics, promising fundamental insights as well as new technologies. The practical operation of an optomechanical system requires that it satisfy the criteria of mechanical stability. Further, for quantum applications, it is important to characterize the degree of nonclassical correlation present between the mechanical and optical subsystems. In this study, we analyze the stability and entanglement in an optomechanical system where couplings linear as well as quadratic in the mechanical displacement are present simultaneously. Such systems can be realized experimentally. Our analysis of the …

Quantum Dot Enhanced Epitaxial Lift-Off Solar Cells, Mitchell F. Bennett

Theses

Embedded nanostructures such as quantum dots (QDs) have been studied for many applications in solar cells including enhanced mini-band absorption in intermediate-band solar cells and current matching in multi junction cells. The major drawbacks of using such techniques to decrease intrinsic solar cell loss mechanisms are twofold: first, it is difficult to maintain partially populated states using QDs due to a quick thermal extraction of carriers; second, QDs have a weak absorption which necessitates a near-perfect control of QD growth mechanisms to carefully ensure a balance between dot size and density. One avenue for improving absorption into QDs is to …

Group Selection And Key Management Strategies For Ciphertext-Policy Attribute-Based Encryption, Russell F. Martin

Theses

Ciphertext-Policy Attribute-Based Encryption (CPABE) was introduced by Bethencourt, Sahai, and Waters, as an improvement of Identity Based Encryption, allowing fine grained control of access to encrypted files by restricting access to only users whose attributes match that of the monotonic access tree of the encrypted file. Through these modifications, encrypted files can be placed securely on an unsecure server, without fear of malicious users being able to access the files, while allowing each user to have a unique key, reducing the vulnerabilites associated with sharing a key between multiple users.

However, due to the fact that CPABE was designed for …

Analysis Of Polarimetric Synthetic Aperture Radar And Passive Visible Light Polarimetric Imaging Data Fusion For Remote Sensing Applications, Sanjit Maitra

Theses

The recent launch of spaceborne (TerraSAR-X, RADARSAT-2, ALOS-PALSAR, RISAT) and airborne (SIRC, AIRSAR, UAVSAR, PISAR) polarimetric radar sensors, with capability of imaging through day and night in almost all weather conditions, has made polarimetric synthetic aperture radar (PolSAR) image interpretation and analysis an active area of research. PolSAR image classification is sensitive to object orientation and scattering properties. In recent years, significant work has been done in many areas including agriculture, forestry, oceanography, geology, terrain analysis. Visible light passive polarimetric imaging has also emerged as a powerful tool in remote sensing for enhanced information extraction. The intensity image provides information …

Evaluating The Effectiveness Of Design For The Environment Tools To Help Meet Sustainability And Design Goals, Ana Maria Leal-Yepes

Theses

Environmental impacts of electronics are a growing concern because the amount and type of materials used in production of the devices, the impacts to the environment from discarded

electronics and the early retirement of products due to rapidly evolving devices, changing design trends, and perceived technological obsolescence. Design for the Environment is a sustainability strategy that aims to reduce the environmental impacts through techniques that enable sustainability solutions during the design decision-making process. In order to suit the diverse

needs of sustainable design practitioners, there has been a large number of tools for Design for the Environment (DfE) developed, confusing …

Physics-Based Surface Energy Model Optimization For Water Bodies In Cold Climates Using Visible And Calibrated Thermal Infrared Imagery, May V. Casterline

Theses

When tasked with accurately modeling a water body in a cold climate environment, the complexity of the system being simulated and the numerous parameters affecting the observable outcome pose an arduous task for any modeling effort. The task is increasingly complicated when the body of water is serving as a cooling pond for a power plant and can become partially frozen. The introduction of a heat effluent into the water creates a highly dynamic system whose physical state is not only reactionary to the surrounding environmental conditions, but the industrial facility's operating parameters as well. Both calibrated thermal and visible …

Rule-Based Conditional Trust With Openpgp., Andrew Jackson

Theses

This thesis describes a new trust model for OpenPGP encryption. This trust model uses conditional rule-based trust to establish key validity and trust. This thesis describes "Trust Rules" that may be used to sort and categorize keys automatically without user interaction. "Trust Rules" are also capable of integrating key revocation status into its calculations so it too is automated. This thesis presents that conditional trust established through "Trust Rules" can enforce stricter security while reducing the burden of use and automating the process of key validity, trust, and revocation.

A Forensic Comparison: Windows 7 And Windows 8, Peter J. Wilson

Theses

Whenever a new operating system or new version of an operating system is released, forensic investigators must re-examine the new operating system or new version. They do so to determine if there are significant differences that will impact and change the way they perform their investigations. With the release of Microsoft's latest operating system, Windows 8, and its update, Windows 8.1, understanding the similarities and differences between Windows 8 and previous operating systems such as Windows 7 is critical. This paper forensically examines Windows 7 and Windows 8 to determine those similarities and differences.

Segmentation And Model Generation For Large-Scale Cyber Attacks, Steven E. Strapp

Theses

Raw Cyber attack traffic can present more questions than answers to security analysts. Especially with large-scale observables it is difficult to identify which packets are relevant and what attack behaviors are present. Many existing works in Host or Flow Clustering attempt to group similar behaviors to expedite analysis; these works often phrase the problem directly as offline unsupervised machine learning. This work proposes online processing to simultaneously model coordinating actors and segment traffic that is relevant to a target of interest, all while it is being received. The goal is not just to aggregate similar attack behaviors, but to provide …

Understanding Effects Of Presentation On Concept Learning In Technology Supported Learning, Nivedita Singh

Theses

The world of technology has had a significant impact on learning and instructional domain. Today, a large number of devices and software are specifically designed to afford faster and effective learning and instruction. They have not only erased the physical boundaries to resources in education but have also helped create new interactions and engagements for learners and instructors. With this changed scenario, the content or instructional material also needs our attention to become usable and compatible with the changed learning styles and preferences of the learners today. Not only does the content need to seamlessly integrate with the delivery methodology …