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  Partner: UNT Libraries
 Language: English
 Degree Discipline: Computer Science
 Collection: UNT Theses and Dissertations
A Smooth-turn Mobility Model for Airborne Networks

A Smooth-turn Mobility Model for Airborne Networks

Date: August 2012
Creator: He, Dayin
Description: In this article, I introduce a novel airborne network mobility model, called the Smooth Turn Mobility Model, that captures the correlation of acceleration for airborne vehicles across time and spatial coordinates. E?ective routing in airborne networks (ANs) relies on suitable mobility models that capture the random movement pattern of airborne vehicles. As airborne vehicles cannot make sharp turns as easily as ground vehicles do, the widely used mobility models for Mobile Ad Hoc Networks such as Random Waypoint and Random Direction models fail. Our model is realistic in capturing the tendency of airborne vehicles toward making straight trajectory and smooth turns with large radius, and whereas is simple enough for tractable connectivity analysis and routing design.
Contributing Partner: UNT Libraries
Automatic Tagging of Communication Data

Automatic Tagging of Communication Data

Date: August 2012
Creator: Hoyt, Matthew Ray
Description: Globally distributed software teams are widespread throughout industry. But finding reliable methods that can properly assess a team's activities is a real challenge. Methods such as surveys and manual coding of activities are too time consuming and are often unreliable. Recent advances in information retrieval and linguistics, however, suggest that automated and/or semi-automated text classification algorithms could be an effective way of finding differences in the communication patterns among individuals and groups. Communication among group members is frequent and generates a significant amount of data. Thus having a web-based tool that can automatically analyze the communication patterns among global software teams could lead to a better understanding of group performance. The goal of this thesis, therefore, is to compare automatic and semi-automatic measures of communication and evaluate their effectiveness in classifying different types of group activities that occur within a global software development project. In order to achieve this goal, we developed a web-based component that can be used to help clean and classify communication activities. The component was then used to compare different automated text classification techniques on various group activities to determine their effectiveness in correctly classifying data from a global software development team project.
Contributing Partner: UNT Libraries
Multi-perspective, Multi-modal Image Registration and Fusion

Multi-perspective, Multi-modal Image Registration and Fusion

Date: August 2012
Creator: Belkhouche, Mohammed Yassine
Description: Multi-modal image fusion is an active research area with many civilian and military applications. Fusion is defined as strategic combination of information collected by various sensors from different locations or different types in order to obtain a better understanding of an observed scene or situation. Fusion of multi-modal images cannot be completed unless these two modalities are spatially aligned. In this research, I consider two important problems. Multi-modal, multi-perspective image registration and decision level fusion of multi-modal images. In particular, LiDAR and visual imagery. Multi-modal image registration is a difficult task due to the different semantic interpretation of features extracted from each modality. This problem is decoupled into three sub-problems. The first step is identification and extraction of common features. The second step is the determination of corresponding points. The third step consists of determining the registration transformation parameters. Traditional registration methods use low level features such as lines and corners. Using these features require an extensive optimization search in order to determine the corresponding points. Many methods use global positioning systems (GPS), and a calibrated camera in order to obtain an initial estimate of the camera parameters. The advantages of our work over the previous works are the following. ...
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Cuff-less Blood Pressure Measurement Using a Smart Phone

Cuff-less Blood Pressure Measurement Using a Smart Phone

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Date: May 2012
Creator: Jonnada, Srikanth
Description: Blood pressure is vital sign information that physicians often need as preliminary data for immediate intervention during emergency situations or for regular monitoring of people with cardiovascular diseases. Despite the availability of portable blood pressure meters in the market, they are not regularly carried by people, creating a need for an ultra-portable measurement platform or device that can be easily carried and used at all times. One such device is the smartphone which, according to comScore survey is used by 26.2% of the US adult population. the mass production of these phones with built-in sensors and high computation power has created numerous possibilities for application development in different domains including biomedical. Motivated by this capability and their extensive usage, this thesis focuses on developing a blood pressure measurement platform on smartphones. Specifically, I developed a blood pressure measurement system on a smart phone using the built-in camera and a customized external microphone. the system consists of first obtaining heart beats using the microphone and finger pulse with the camera, and finally calculating the blood pressure using the recorded data. I developed techniques for finding the best location for obtaining the data, making the system usable by all categories of people. ...
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Group-EDF: A new approach and an efficient non-preemptive algorithm for soft real-time systems.

Group-EDF: A new approach and an efficient non-preemptive algorithm for soft real-time systems.

Access: Use of this item is restricted to the UNT Community.
Date: August 2006
Creator: Li, Wenming
Description: Hard real-time systems in robotics, space and military missions, and control devices are specified with stringent and critical time constraints. On the other hand, soft real-time applications arising from multimedia, telecommunications, Internet web services, and games are specified with more lenient constraints. Real-time systems can also be distinguished in terms of their implementation into preemptive and non-preemptive systems. In preemptive systems, tasks are often preempted by higher priority tasks. Non-preemptive systems are gaining interest for implementing soft-real applications on multithreaded platforms. In this dissertation, I propose a new algorithm that uses a two-level scheduling strategy for scheduling non-preemptive soft real-time tasks. Our goal is to improve the success ratios of the well-known earliest deadline first (EDF) approach when the load on the system is very high and to improve the overall performance in both underloaded and overloaded conditions. Our approach, known as group-EDF (gEDF), is based on dynamic grouping of tasks with deadlines that are very close to each other, and using a shortest job first (SJF) technique to schedule tasks within the group. I believe that grouping tasks dynamically with similar deadlines and utilizing secondary criteria, such as minimizing the total execution time can lead to new and more ...
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Bayesian Probabilistic Reasoning Applied to Mathematical Epidemiology for Predictive Spatiotemporal Analysis of Infectious Diseases

Bayesian Probabilistic Reasoning Applied to Mathematical Epidemiology for Predictive Spatiotemporal Analysis of Infectious Diseases

Date: May 2006
Creator: Abbas, Kaja Moinudeen
Description: Abstract Probabilistic reasoning under uncertainty suits well to analysis of disease dynamics. The stochastic nature of disease progression is modeled by applying the principles of Bayesian learning. Bayesian learning predicts the disease progression, including prevalence and incidence, for a geographic region and demographic composition. Public health resources, prioritized by the order of risk levels of the population, will efficiently minimize the disease spread and curtail the epidemic at the earliest. A Bayesian network representing the outbreak of influenza and pneumonia in a geographic region is ported to a newer region with different demographic composition. Upon analysis for the newer region, the corresponding prevalence of influenza and pneumonia among the different demographic subgroups is inferred for the newer region. Bayesian reasoning coupled with disease timeline is used to reverse engineer an influenza outbreak for a given geographic and demographic setting. The temporal flow of the epidemic among the different sections of the population is analyzed to identify the corresponding risk levels. In comparison to spread vaccination, prioritizing the limited vaccination resources to the higher risk groups results in relatively lower influenza prevalence. HIV incidence in Texas from 1989-2002 is analyzed using demographic based epidemic curves. Dynamic Bayesian networks are integrated with ...
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The Multipath Fault-Tolerant Protocol for Routing in Packet-Switched Communication Network

The Multipath Fault-Tolerant Protocol for Routing in Packet-Switched Communication Network

Date: May 2003
Creator: Krishnan, Anupama
Description: In order to provide improved service quality to applications, networks need to address the need for reliability of data delivery. Reliability can be improved by incorporating fault tolerance into network routing, wherein a set of multiple routes are used for routing between a given source and destination. This thesis proposes a new fault-tolerant protocol, called the Multipath Fault Tolerant Protocol for Routing (MFTPR), to improve the reliability of network routing services. The protocol is based on a multipath discovery algorithm, the Quasi-Shortest Multipath (QSMP), and is designed to work in conjunction with the routing protocol employed by the network. MFTPR improves upon the QSMP algorithm by finding more routes than QSMP, and also provides for maintenance of these routes in the event of failure of network components. In order to evaluate the resilience of a pair of paths to failure, this thesis proposes metrics that evaluate the non-disjointness of a pair of paths and measure the probability of simultaneous failure of these paths. The performance of MFTPR to find alternate routes based on these metrics is analyzed through simulation.
Contributing Partner: UNT Libraries
DICOM Image Scrubbing Software Library/Utility

DICOM Image Scrubbing Software Library/Utility

Date: May 2003
Creator: Ponnam, Bhavani Srikanth
Description: This software is aimed at providing user-friendly, easy-to-use environment for the user to scrub (de-identify/modify) the DICOM header information. Some tools either anonymize or default the values without the user interaction. The user doesn't have the flexibility to edit the header information. One cannot scrub set of images simultaneously (batch scrubbing). This motivated to develop a tool/utility that can scrub a set of images in a single step more efficiently. This document also addresses security issues of the patient confidentiality to achieve protection of patient identifying information and some technical requirements
Contributing Partner: UNT Libraries
Study and Sample Implementation of the Secure Shell Protocol (SSH)

Study and Sample Implementation of the Secure Shell Protocol (SSH)

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Date: May 2003
Creator: Subramanyam, Udayakiran
Description: Security is one of the main concerns of users who need to connect to a remote computer for various purposes, such as checking e-mails or viewing files. However in today's computer networks, privacy, transmission to intended client is not guaranteed. If data is transmitted over the Internet or a local network as plain text it may be captured and viewed by anyone with little technical knowledge. This may include sensitive data such as passwords. Big businesses use firewalls, virtual private networks and encrypt their transmissions to counter this at high costs. Secure shell protocol (SSH) provides an answer to this. SSH is a software protocol for secure communication over an insecure network. SSH not only offers authentication of hosts but also encrypts the sessions between the client and the server and is transparent to the end user. This Problem in Lieu of Thesis makes a study of SSH and creates a sample secure client and server which follows SSH and examines its performance.
Contributing Partner: UNT Libraries
Security problems in 802.11 wireless networks standard due to the inefficiency of wired equivalent privacy protocol.

Security problems in 802.11 wireless networks standard due to the inefficiency of wired equivalent privacy protocol.

Date: May 2003
Creator: Samanthapudi, Varma
Description: Due to the rapid growth of wireless networking, the fallible security issues of the 802.11 standard have come under close scrutiny. Nowadays most of the organizations are eager to setup wireless local area networks to reduce the hassles of limited mobility provided by conventional wired network. There are serious security issues that need to be sorted out before everyone is willing to transmit valuable corporate information on a wireless network. This report documents the inherent flaws in wired equivalent privacy protocol used by the 802.11 standard and the ensuing security breaches that can occur to a wireless network due to these flaws. The solutions suggested in this report might not actually make the 802.11 standard secure, but will surely help in the lead up to a secure wireless network standard.
Contributing Partner: UNT Libraries
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