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Full-Text Articles in Physical Sciences and Mathematics

Providing Context To The Clues: Recovery And Reliability Of Location Data From Android Devices, Connie Bell Jan 2015

Providing Context To The Clues: Recovery And Reliability Of Location Data From Android Devices, Connie Bell

Electronic Theses and Dissertations

Mobile device data continues to increase in significance in both civil and criminal investigations. Location data is often of particular interest. To date, research has established that the devices are location aware, incorporate a variety of resources to obtain location information, and cache the information in various ways. However, a review of the existing research suggests varying degrees of reliability of any such recovered location data. In an effort to clarify the issue, this project offers case studies of multiple Android mobile devices utilized in controlled conditions with known settings and applications in documented locations. The study uses data recovered …


Transverse Mode Selection And Brightness Enhancement In Laser Resonators By Means Of Volume Bragg Gratings, Brian Anderson Jan 2015

Transverse Mode Selection And Brightness Enhancement In Laser Resonators By Means Of Volume Bragg Gratings, Brian Anderson

Electronic Theses and Dissertations

The design of high power lasers requires large mode areas to overcome various intensity driven nonlinear effects. Increasing the aperture size within the laser can overcome these effects, but typically result in multi-transverse mode output and reduced beam quality, limiting the brightness of the system. As one possible solution, the angular selectivity of a diffractive optical element is proposed as a spatial filter, allowing for the design of compact high brightness sources not possible with conventional methods of transverse mode selection. This thesis explores the angular selectivity of volume Bragg gratings (VBGs) and their use as spatial transverse mode filters …


Resource Management In Large-Scale Systems, Ashkan Paya Jan 2015

Resource Management In Large-Scale Systems, Ashkan Paya

Electronic Theses and Dissertations

The focus of this thesis is resource management in large-scale systems. Our primary concerns are energy management and practical principles for self-organization and self-management. The main contributions of our work are: 1. Models. We proposed several models for different aspects of resource management, e.g., energy-aware load balancing and application scaling for the cloud ecosystem, hierarchical architecture model for self-organizing and self-manageable systems and a new cloud delivery model based on auction-driven self-organization approach. 2. Algorithms. We also proposed several different algorithms for the models described above. Algorithms such as coalition formation, combinatorial auctions and clustering algorithm for scale-free organizations of …


The Design, Implementation, And Refinement Of Wait-Free Algorithms And Containers, Steven Feldman Jan 2015

The Design, Implementation, And Refinement Of Wait-Free Algorithms And Containers, Steven Feldman

Electronic Theses and Dissertations

My research has been on the development of concurrent algorithms for shared memory systems that provide guarantees of progress. Research into such algorithms is important to developers implementing applications on mission critical and time sensitive systems. These guarantees of progress provide safety properties and freedom from many hazards, such as dead-lock, live-lock, and thread starvation. In addition to the safety concerns, the fine-grained synchronization used in implementing these algorithms promises to provide scalable performance in massively parallel systems. My research has resulted in the development of wait-free versions of the stack, hash map, ring buffer, vector, and a multi-word compare-and-swap …


Low Absorption Liquid Crystal Materials For Midwave Infrared, Amy Creekmore Jan 2015

Low Absorption Liquid Crystal Materials For Midwave Infrared, Amy Creekmore

Electronic Theses and Dissertations

Liquid crystal is an amazing class of soft matters with applications spanning from visible, infrared, millimeter wave, to terahertz. In addition to direct-view displays and projection displays, liquid crystal is also widely used in adaptive optics, tunable-focus lens, and laser beam steering. Although the visible region has well developed materials and mixtures for the vast variety of applications, the midwave infrared (MWIR) region of the electromagnetic spectrum invites much development as only a few materials have been developed with these applications in mind. Unlike visible region, the major challenge for mid-wave infrared liquid crystal is inherently large absorption loss. To …


Opportunistic Spectrum Utilization By Cognitive Radio Networks: Challenges And Solutions, Muhammad Faisal Amjad Jan 2015

Opportunistic Spectrum Utilization By Cognitive Radio Networks: Challenges And Solutions, Muhammad Faisal Amjad

Electronic Theses and Dissertations

Cognitive Radio Network (CRN) is an emerging paradigm that makes use of Dynamic Spectrum Access (DSA) to communicate opportunistically, in the un-licensed Industrial, Scientific and Medical bands or frequency bands otherwise licensed to incumbent users such as TV broadcast. Interest in the development of CRNs is because of severe under-utilization of spectrum bands by the incumbent Primary Users (PUs) that have the license to use them coupled with an ever-increasing demand for unlicensed spectrum for a variety of new mobile and wireless applications. The essence of Cognitive Radio (CR) operation is the cooperative and opportunistic utilization of licensed spectrum bands …


White Light Continuum For Broadband Nonlinear Spectroscopy, Trenton Ensley Jan 2015

White Light Continuum For Broadband Nonlinear Spectroscopy, Trenton Ensley

Electronic Theses and Dissertations

Supercontinuum (SC) generation, oftentimes referred to as white-light continuum (WLC), has been a subject of interest for more than 40 years. From the first observation of WLC in condensed media in the early 1970s to the first observation of WLC in gases in the mid-1980s, much work has been devoted to developing a framework for understanding the complex nature of this phenomenon as well as discovering its utility in various applications. The main effort of this dissertation is to develop a WLC for the purpose of broadband nonlinear spectroscopy and use it in spectroscopic measurements. The ability to generate a …


Testing Data Vault-Based Data Warehouse, Connard N. Williams Jan 2015

Testing Data Vault-Based Data Warehouse, Connard N. Williams

Electronic Theses and Dissertations

Data warehouse (DW) projects are undertakings that require integration of disparate sources of data, a well-defined mapping of the source data to the reconciled data, and effective Extract, Transform, and Load (ETL) processes. Owing to the complexity of data warehouse projects, great emphasis must be placed on an agile-based approach with properly developed and executed test plans throughout the various stages of designing, developing, and implementing the data warehouse to mitigate against budget overruns, missed deadlines, low customer satisfaction, and outright project failures. Yet, there are often attempts to test the data warehouse exactly like traditional back-end databases and legacy …