Search Results

open access

Location Estimation and Geo-Correlated Information Trends

Description: A tremendous amount of information is being shared every day on social media sites such as Facebook, Twitter or Google+. However, only a small portion of users provide their location information, which can be helpful in targeted advertising and many other services. Current methods in location estimation using social relationships consider social friendship as a simple binary relationship. However, social closeness between users and structure of friends have strong implications on geographic dis… more
Date: December 2017
Creator: Liu, Zhi
Partner: UNT Libraries
open access

Evaluation of Call Mobility on Network Productivity in Long Term Evolution Advanced (LTE-A) Femtocells

Description: The demand for higher data rates for indoor and cell-edge users led to evolution of small cells. LTE femtocells, one of the small cell categories, are low-power low-cost mobile base stations, which are deployed within the coverage area of the traditional macro base station. The cross-tier and co-tier interferences occur only when the macrocell and femtocell share the same frequency channels. Open access (OSG), closed access (CSG), and hybrid access are the three existing access-control methods … more
Date: December 2017
Creator: Sawant, Uttara
Partner: UNT Libraries
open access

The Influence of Social Network Graph Structure on Disease Dynamics in a Simulated Environment

Description: The fight against epidemics/pandemics is one of man versus nature. Technological advances have not only improved existing methods for monitoring and controlling disease outbreaks, but have also provided new means for investigation, such as through modeling and simulation. This dissertation explores the relationship between social structure and disease dynamics. Social structures are modeled as graphs, and outbreaks are simulated based on a well-recognized standard, the susceptible-infectious… more
Date: December 2010
Creator: Johnson, Tina V.
Partner: UNT Libraries
open access

Statistical Strategies for Efficient Signal Detection and Parameter Estimation in Wireless Sensor Networks

Description: This dissertation investigates data reduction strategies from a signal processing perspective in centralized detection and estimation applications. First, it considers a deterministic source observed by a network of sensors and develops an analytical strategy for ranking sensor transmissions based on the magnitude of their test statistics. The benefit of the proposed strategy is that the decision to transmit or not to transmit observations to the fusion center can be made at the sensor level re… more
Date: December 2013
Creator: Ayeh, Eric
Partner: UNT Libraries
open access

Real Time Assessment of a Video Game Player's State of Mind Using Off-the-Shelf Electroencephalography

Description: The focus of this research is on the development of a real time application that uses a low cost EEG headset to measure a player's state of mind while they play a video game. Using data collected using the Emotiv EPOC headset, various EEG processing techniques are tested to find ways of measuring a person's engagement and arousal levels. The ability to measure a person's engagement and arousal levels provide an opportunity to develop a model that monitor a person's flow while playing video game… more
Date: December 2016
Creator: McMahan, Timothy
Partner: UNT Libraries
open access

Infusing Automatic Question Generation with Natural Language Understanding

Description: Automatically generating questions from text for educational purposes is an active research area in natural language processing. The automatic question generation system accompanying this dissertation is MARGE, which is a recursive acronym for: MARGE automatically reads generates and evaluates. MARGE generates questions from both individual sentences and the passage as a whole, and is the first question generation system to successfully generate meaningful questions from textual units larger th… more
Date: December 2016
Creator: Mazidi, Karen
Partner: UNT Libraries
open access

Comparative Study of RSS-Based Collaborative Localization Methods in Wireless Sensor Networks

Description: In this thesis two collaborative localization techniques are studied: multidimensional scaling (MDS) and maximum likelihood estimator (MLE). A synthesis of a new location estimation method through a serial integration of these two techniques, such that an estimate is first obtained using MDS and then MLE is employed to fine-tune the MDS solution, was the subject of this research using various simulation and experimental studies. In the simulations, important issues including the effects of sens… more
Date: December 2006
Creator: Koneru, Avanthi
Partner: UNT Libraries
open access

Ontology Based Security Threat Assessment and Mitigation for Cloud Systems

Description: A malicious actor often relies on security vulnerabilities of IT systems to launch a cyber attack. Most cloud services are supported by an orchestration of large and complex systems which are prone to vulnerabilities, making threat assessment very challenging. In this research, I developed formal and practical ontology-based techniques that enable automated evaluation of a cloud system's security threats. I use an architecture for threat assessment of cloud systems that leverages a dynamically … more
Date: December 2018
Creator: Kamongi, Patrick
Partner: UNT Libraries
open access

Toward Supporting Fine-Grained, Structured, Meaningful and Engaging Feedback in Educational Applications

Description: Recent advancements in machine learning have started to put their mark on educational technology. Technology is evolving fast and, as people adopt it, schools and universities must also keep up (nearly 70% of primary and secondary schools in the UK are now using tablets for various purposes). As these numbers are likely going to follow the same increasing trend, it is imperative for schools to adapt and benefit from the advantages offered by technology: real-time processing of data, availabilit… more
Date: December 2018
Creator: Bulgarov, Florin Adrian
Partner: UNT Libraries
open access

Improving Software Quality through Syntax and Semantics Verification of Requirements Models

Description: Software defects can frequently be traced to poorly-specified requirements. Many software teams manage their requirements using tools such as checklists and databases, which lack a formal semantic mapping to system behavior. Such a mapping can be especially helpful for safety-critical systems. Another limitation of many requirements analysis methods is that much of the analysis must still be done manually. We propose techniques that automate portions of the requirements analysis process, as wel… more
Date: December 2018
Creator: Gaither, Danielle
Partner: UNT Libraries

A Performance and Security Analysis of Elliptic Curve Cryptography Based Real-Time Media Encryption

Description: This dissertation emphasizes the security aspects of real-time media. The problems of existing real-time media protections are identified in this research, and viable solutions are proposed. First, the security of real-time media depends on the Secure Real-time Transport Protocol (SRTP) mechanism. We identified drawbacks of the existing SRTP Systems, which use symmetric key encryption schemes, which can be exploited by attackers. Elliptic Curve Cryptography (ECC), an asymmetric key cryptography… more
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Date: December 2019
Creator: Sen, Nilanjan
Partner: UNT Libraries
open access

Online Construction of Android Application Test Suites

Description: Mobile applications play an important role in the dissemination of computing and information resources. They are often used in domains such as mobile banking, e-commerce, and health monitoring. Cost-effective testing techniques in these domains are critical. This dissertation contributes novel techniques for automatic construction of mobile application test suites. In particular, this work provides solutions that focus on the prohibitively large number of possible event sequences that must be s… more
Date: December 2017
Creator: Adamo, David T., Jr.
Partner: UNT Libraries

Understanding and Addressing Accessibility Barriers Faced by People with Visual Impairments on Block-Based Programming Environments

Description: There is an increased use of block-based programming environments in K-12 education and computing outreach activities to introduce novices to programming and computational thinking skills. However, despite their appealing design that allows students to focus on concepts rather than syntax, block-based programming by design is inaccessible to people with visual impairments and people who cannot use the mouse. In addition to this inaccessibility, little is known about the instructional experience… more
Date: December 2022
Creator: Mountapmbeme, Aboubakar
Partner: UNT Libraries
open access

Detection and Classification of Heart Sounds Using a Heart-Mobile Interface

Description: An early detection of heart disease can save lives, caution individuals and also help to determine the type of treatment to be given to the patients. The first test of diagnosing a heart disease is through auscultation - listening to the heart sounds. The interpretation of heart sounds is subjective and requires a professional skill to identify the abnormalities in these sounds. A medical practitioner uses a stethoscope to perform an initial screening by listening for irregular sounds from the … more
Date: December 2016
Creator: Thiyagaraja, Shanti
Partner: UNT Libraries
open access

Improving Memory Performance for Both High Performance Computing and Embedded/Edge Computing Systems

Description: CPU-memory bottleneck is a widely recognized problem. It is known that majority of high performance computing (HPC) database systems are configured with large memories and dedicated to process specific workloads like weather prediction, molecular dynamic simulations etc. My research on optimal address mapping improves the memory performance by increasing the channel and bank level parallelism. In an another research direction, I proposed and evaluated adaptive page migration techniques that o… more
Date: December 2021
Creator: Adavally, Shashank
Partner: UNT Libraries

Online Testing of Context-Aware Android Applications

Description: This dissertation presents novel approaches to test context aware applications that suffer from a cost prohibitive number of context and GUI events and event combinations. The contributions of this work to test context aware applications under test include: (1) a real-world context events dataset from 82 Android users over a 30-day period, (2) applications of Markov models, Closed Sequential Pattern Mining (CloSPAN), Deep Neural Networks- Long Short Term Memory (LSTM) and Gated Recurrent Units … more
Date: December 2021
Creator: Piparia, Shraddha
Partner: UNT Libraries
open access

Machine-Learning-Enabled Cooperative Perception on Connected Autonomous Vehicles

Description: The main research objective of this dissertation is to understand the sensing and communication challenges to achieving cooperative perception among autonomous vehicles, and then, using the insights gained, guide the design of the suitable format of data to be exchanged, reliable and efficient data fusion algorithms on vehicles. By understanding what and how data are exchanged among autonomous vehicles, from a machine learning perspective, it is possible to realize precise cooperative perceptio… more
Date: December 2021
Creator: Guo, Jingda
Partner: UNT Libraries
open access

SIMON: A Domain-Agnostic Framework for Secure Design and Validation of Cyber Physical Systems

Description: Cyber physical systems (CPS) are an integration of computational and physical processes, where the cyber components monitor and control physical processes. Cyber-attacks largely target the cyber components with the intention of disrupting the functionality of the components in the physical domain. This dissertation explores the role of semantic inference in understanding such attacks and building resilient CPS systems. To that end, we present SIMON, an ontological design and verification framew… more
Date: December 2021
Creator: Yanambaka Venkata, Rohith
Partner: UNT Libraries
open access

Inferring Social and Internal Context Using a Mobile Phone

Description: This dissertation is composed of research studies that contribute to three research areas including social context-aware computing, internal context-aware computing, and human behavioral data mining. In social context-aware computing, four studies are conducted. First, mobile phone user calling behavioral patterns are characterized in forms of randomness level where relationships among them are then identified. Next, a study is conducted to investigate the relationship between the calling behav… more
Date: December 2009
Creator: Phithakkitnukoon, Santi
Partner: UNT Libraries
open access

E‐Shape Analysis

Description: The motivation of this work is to understand E-shape analysis and how it can be applied to various classification tasks. It has a powerful feature to not only look at what information is contained, but rather how that information looks. This new technique gives E-shape analysis the ability to be language independent and to some extent size independent. In this thesis, I present a new mechanism to characterize an email without using content or context called E-shape analysis for email. I expl… more
Date: December 2009
Creator: Sroufe, Paul
Partner: UNT Libraries
open access

The Value of Everything: Ranking and Association with Encyclopedic Knowledge

Description: This dissertation describes WikiRank, an unsupervised method of assigning relative values to elements of a broad coverage encyclopedic information source in order to identify those entries that may be relevant to a given piece of text. The valuation given to an entry is based not on textual similarity but instead on the links that associate entries, and an estimation of the expected frequency of visitation that would be given to each entry based on those associations in context. This estimati… more
Date: December 2009
Creator: Coursey, Kino High
Partner: UNT Libraries
open access

Indoor Localization Using Magnetic Fields

Description: Indoor localization consists of locating oneself inside new buildings. GPS does not work indoors due to multipath reflection and signal blockage. WiFi based systems assume ubiquitous availability and infrastructure based systems require expensive installations, hence making indoor localization an open problem. This dissertation consists of solving the problem of indoor localization by thoroughly exploiting the indoor ambient magnetic fields comprising mainly of disturbances termed as anomalies … more
Date: December 2011
Creator: Pathapati Subbu, Kalyan Sasidhar
Partner: UNT Libraries
open access

Modeling Synergistic Relationships Between Words and Images

Description: Texts and images provide alternative, yet orthogonal views of the same underlying cognitive concept. By uncovering synergistic, semantic relationships that exist between words and images, I am working to develop novel techniques that can help improve tasks in natural language processing, as well as effective models for text-to-image synthesis, image retrieval, and automatic image annotation. Specifically, in my dissertation, I will explore the interoperability of features between language and v… more
Date: December 2012
Creator: Leong, Chee Wee
Partner: UNT Libraries
open access

Source and Channel Coding Strategies for Wireless Sensor Networks

Description: In this dissertation, I focus on source coding techniques as well as channel coding techniques. I addressed the challenges in WSN by developing (1) a new source coding strategy for erasure channels that has better distortion performance compared to MDC; (2) a new cooperative channel coding strategy for multiple access channels that has better channel outage performances compared to MIMO; (3) a new source-channel cooperation strategy to accomplish source-to-fusion center communication that reduc… more
Date: December 2012
Creator: Li, Li
Partner: UNT Libraries
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