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  Partner: UNT Libraries
 Degree Discipline: Computer Science
 Collection: UNT Theses and Dissertations
Socioscope: Human Relationship and Behavior Analysis in Mobile Social Networks

Socioscope: Human Relationship and Behavior Analysis in Mobile Social Networks

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Date: August 2010
Creator: Zhang, Huiqi
Description: The widely used mobile phone, as well as its related technologies had opened opportunities for a complete change on how people interact and build relationship across geographic and time considerations. The convenience of instant communication by mobile phones that broke the barrier of space and time is evidently the key motivational point on why such technologies so important in people's life and daily activities. Mobile phones have become the most popular communication tools. Mobile phone technology is apparently changing our relationship to each other in our work and lives. The impact of new technologies on people's lives in social spaces gives us the chance to rethink the possibilities of technologies in social interaction. Accordingly, mobile phones are basically changing social relations in ways that are intricate to measure with any precision. In this dissertation I propose a socioscope model for social network, relationship and human behavior analysis based on mobile phone call detail records. Because of the diversities and complexities of human social behavior, one technique cannot detect different features of human social behaviors. Therefore I use multiple probability and statistical methods for quantifying social groups, relationships and communication patterns, for predicting social tie strengths and for detecting human behavior ...
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Design and Implementation of Large-Scale Wireless Sensor Networks for Environmental Monitoring Applications

Design and Implementation of Large-Scale Wireless Sensor Networks for Environmental Monitoring Applications

Date: May 2010
Creator: Yang, Jue
Description: Environmental monitoring represents a major application domain for wireless sensor networks (WSN). However, despite significant advances in recent years, there are still many challenging issues to be addressed to exploit the full potential of the emerging WSN technology. In this dissertation, we introduce the design and implementation of low-power wireless sensor networks for long-term, autonomous, and near-real-time environmental monitoring applications. We have developed an out-of-box solution consisting of a suite of software, protocols and algorithms to provide reliable data collection with extremely low power consumption. Two wireless sensor networks based on the proposed solution have been deployed in remote field stations to monitor soil moisture along with other environmental parameters. As parts of the ever-growing environmental monitoring cyberinfrastructure, these networks have been integrated into the Texas Environmental Observatory system for long-term operation. Environmental measurement and network performance results are presented to demonstrate the capability, reliability and energy-efficiency of the network.
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Force-Directed Graph Drawing and Aesthetics Measurement in a Non-Strict Pure Functional Programming Language

Force-Directed Graph Drawing and Aesthetics Measurement in a Non-Strict Pure Functional Programming Language

Date: December 2009
Creator: Gaconnet, Christopher James
Description: Non-strict pure functional programming often requires redesigning algorithms and data structures to work more effectively under new constraints of non-strict evaluation and immutable state. Graph drawing algorithms, while numerous and broadly studied, have no presence in the non-strict pure functional programming model. Additionally, there is currently no freely licensed standalone toolkit used to quantitatively analyze aesthetics of graph drawings. This thesis addresses two previously unexplored questions. Can a force-directed graph drawing algorithm be implemented in a non-strict functional language, such as Haskell, and still be practically usable? Can an easily extensible aesthetic measuring tool be implemented in a language such as Haskell and still be practically usable? The focus of the thesis is on implementing one of the simplest force-directed algorithms, that of Fruchterman and Reingold, and comparing its resulting aesthetics to those of a well-known C++ implementation of the same algorithm.
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Survey of Approximation Algorithms for Set Cover Problem

Survey of Approximation Algorithms for Set Cover Problem

Date: December 2009
Creator: Dutta, Himanshu Shekhar
Description: In this thesis, I survey 11 approximation algorithms for unweighted set cover problem. I have also implemented the three algorithms and created a software library that stores the code I have written. The algorithms I survey are: 1. Johnson's standard greedy; 2. f-frequency greedy; 3. Goldsmidt, Hochbaum and Yu's modified greedy; 4. Halldorsson's local optimization; 5. Dur and Furer semi local optimization; 6. Asaf Levin's improvement to Dur and Furer; 7. Simple rounding; 8. Randomized rounding; 9. LP duality; 10. Primal-dual schema; and 11. Network flow technique. Most of the algorithms surveyed are refinements of standard greedy algorithm.
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Urban surface characterization using LiDAR and aerial imagery.

Urban surface characterization using LiDAR and aerial imagery.

Date: December 2009
Creator: Sarma, Vaibhav
Description: Many calamities in history like hurricanes, tornado and flooding are proof to the large scale impact they cause to the life and economy. Computer simulation and GIS helps in modeling a real world scenario, which assists in evacuation planning, damage assessment, assistance and reconstruction. For achieving computer simulation and modeling there is a need for accurate classification of ground objects. One of the most significant aspects of this research is that it achieves improved classification for regions within which light detection and ranging (LiDAR) has low spatial resolution. This thesis describes a method for accurate classification of bare ground, water body, roads, vegetation, and structures using LiDAR data and aerial Infrared imagery. The most basic step for any terrain modeling application is filtering which is classification of ground and non-ground points. We present an integrated systematic method that makes classification of terrain and non-terrain points effective. Our filtering method uses the geometric feature of the triangle meshes created from LiDAR samples and calculate the confidence for every point. Geometric homogenous blocks and confidence are derived from TIN model and gridded LiDAR samples. The results from two representations are used in a classifier to determine if the block belongs ground or ...
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Computational Epidemiology - Analyzing Exposure Risk: A Deterministic, Agent-Based Approach

Computational Epidemiology - Analyzing Exposure Risk: A Deterministic, Agent-Based Approach

Date: August 2009
Creator: O'Neill II, Martin Joseph
Description: Many infectious diseases are spread through interactions between susceptible and infectious individuals. Keeping track of where each exposure to the disease took place, when it took place, and which individuals were involved in the exposure can give public health officials important information that they may use to formulate their interventions. Further, knowing which individuals in the population are at the highest risk of becoming infected with the disease may prove to be a useful tool for public health officials trying to curtail the spread of the disease. Epidemiological models are needed to allow epidemiologists to study the population dynamics of transmission of infectious agents and the potential impact of infectious disease control programs. While many agent-based computational epidemiological models exist in the literature, they focus on the spread of disease rather than exposure risk. These models are designed to simulate very large populations, representing individuals as agents, and using random experiments and probabilities in an attempt to more realistically guide the course of the modeled disease outbreak. The work presented in this thesis focuses on tracking exposure risk to chickenpox in an elementary school setting. This setting is chosen due to the high level of detailed information realistically available to ...
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End of Insertion Detection in Colonoscopy Videos

End of Insertion Detection in Colonoscopy Videos

Date: August 2009
Creator: Malik, Avnish Rajbal
Description: Colorectal cancer is the second leading cause of cancer-related deaths behind lung cancer in the United States. Colonoscopy is the preferred screening method for detection of diseases like Colorectal Cancer. In the year 2006, American Society for Gastrointestinal Endoscopy (ASGE) and American College of Gastroenterology (ACG) issued guidelines for quality colonoscopy. The guidelines suggest that on average the withdrawal phase during a screening colonoscopy should last a minimum of 6 minutes. My aim is to classify the colonoscopy video into insertion and withdrawal phase. The problem is that currently existing shot detection techniques cannot be applied because colonoscopy is a single camera shot from start to end. An algorithm to detect phase boundary has already been developed by the MIGLAB team. Existing method has acceptable levels of accuracy but the main issue is dependency on MPEG (Moving Pictures Expert Group) 1/2. I implemented exhaustive search for motion estimation to reduce the execution time and improve the accuracy. I took advantages of the C/C++ programming languages with multithreading which helped us get even better performances in terms of execution time. I propose a method for improving the current method of colonoscopy video analysis and also an extension for the same to ...
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Cross Language Information Retrieval for Languages with Scarce Resources

Cross Language Information Retrieval for Languages with Scarce Resources

Date: May 2009
Creator: Loza, Christian
Description: Our generation has experienced one of the most dramatic changes in how society communicates. Today, we have online information on almost any imaginable topic. However, most of this information is available in only a few dozen languages. In this thesis, I explore the use of parallel texts to enable cross-language information retrieval (CLIR) for languages with scarce resources. To build the parallel text I use the Bible. I evaluate different variables and their impact on the resulting CLIR system, specifically: (1) the CLIR results when using different amounts of parallel text; (2) the role of paraphrasing on the quality of the CLIR output; (3) the impact on accuracy when translating the query versus translating the collection of documents; and finally (4) how the results are affected by the use of different dialects. The results show that all these variables have a direct impact on the quality of the CLIR system.
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Development, Implementation, and Analysis of a Contact Model for an Infectious Disease

Development, Implementation, and Analysis of a Contact Model for an Infectious Disease

Date: May 2009
Creator: Thompson, Brett Morinaga
Description: With a growing concern of an infectious diseases spreading in a population, epidemiology is becoming more important for the future of public health. In the past epidemiologist used existing data of an outbreak to help them determine how an infectious disease might spread in the future. Now with computational models, they able to analysis data produced by these models to help with prevention and intervention plans. This paper looks at the design, implementation, and analysis of a computational model based on the interactions of the population between individuals. The design of the working contact model looks closely at the SEIR model used as the foundation and the two timelines of a disease. The implementation of the contact model is reviewed while looking closely at data structures. The analysis of the experiments provide evidence this contact model can be used to help epidemiologist study the spread of an infectious disease based on the contact rate of individuals.
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Direct Online/Offline Digital Signature Schemes.

Direct Online/Offline Digital Signature Schemes.

Date: December 2008
Creator: Yu, Ping
Description: Online/offline signature schemes are useful in many situations, and two such scenarios are considered in this dissertation: bursty server authentication and embedded device authentication. In this dissertation, new techniques for online/offline signing are introduced, those are applied in a variety of ways for creating online/offline signature schemes, and five different online/offline signature schemes that are proved secure under a variety of models and assumptions are proposed. Two of the proposed five schemes have the best offline or best online performance of any currently known technique, and are particularly well-suited for the scenarios that are considered in this dissertation. To determine if the proposed schemes provide the expected practical improvements, a series of experiments were conducted comparing the proposed schemes with each other and with other state-of-the-art schemes in this area, both on a desktop class computer, and under AVR Studio, a simulation platform for an 8-bit processor that is popular for embedded systems. Under AVR Studio, the proposed SGE scheme using a typical key size for the embedded device authentication scenario, can complete the offline phase in about 24 seconds and then produce a signature (the online phase) in 15 milliseconds, which is the best offline performance of any known ...
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