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Full-Text Articles in Physical Sciences and Mathematics

Website Adaptive Navigation Effects On User Experiences, James C. Speirs Dec 2012

Website Adaptive Navigation Effects On User Experiences, James C. Speirs

Theses and Dissertations

The information search process within a website can often be frustrating and confusing for website visitors. Navigational structures are often complex and multitiered, hiding links with several layers of navigation that user's might be interested in. Poor navigation causes user frustration. Adaptive navigation can be used to improve the user's navigational experience by flattening the navigational structure and reducing the number of accessible links to only those that the user would be interested in. This examines the effects on a user's navigational experience, of using adaptive navigation as the main navigational structure on a website. This study measured these effects …


Necessary And Sufficient Informativity Conditions For Robust Network Reconstruction Using Dynamical Structure Functions, Vasu Nephi Chetty Dec 2012

Necessary And Sufficient Informativity Conditions For Robust Network Reconstruction Using Dynamical Structure Functions, Vasu Nephi Chetty

Theses and Dissertations

Dynamical structure functions were developed as a partial structure representation of linear time-invariant systems to be used in the reconstruction of biological networks. Dynamical structure functions contain more information about structure than a system's transfer function, while requiring less a priori information for reconstruction than the complete computational structure associated with the state space realization. Early sufficient conditions for network reconstruction with dynamical structure functions severely restricted the possible applications of the reconstruction process to networks where each input independently controls a measured state. The first contribution of this thesis is to extend the previously established sufficient conditions to incorporate …


Data Acquisition From Cemetery Headstones, Cameron Smith Christiansen Nov 2012

Data Acquisition From Cemetery Headstones, Cameron Smith Christiansen

Theses and Dissertations

Data extraction from engraved text is discussed rarely, and nothing in the open literature discusses data extraction from cemetery headstones. Headstone images present unique challenges such as engraved or embossed characters (causing inner-character shadows), low contrast with the background, and significant noise due to inconsistent stone texture and weathering. Current systems for extracting text from outdoor environments (billboards, signs, etc.) make assumptions (i.e. clean and/or consistently-textured background and text) that fail when applied to the domain of engraved text. Additionally, the ability to extract the data found on headstones is of great historical value. This thesis describes a novel and …


Algorithmically Flexible Style Composition Through Multi-Objective Fitness Functions, Skyler James Murray Nov 2012

Algorithmically Flexible Style Composition Through Multi-Objective Fitness Functions, Skyler James Murray

Theses and Dissertations

Creating a fitness function for music is largely subjective and dependent on a programmer's personal tastes or goals. Previous attempts to create musical fitness functions for use in genetic algorithms lack scope or are prejudiced to a certain genre of music. They also suffer the limitation of producing music only in the strict style determined by the programmer. We show in this paper that musical feature extractors that avoid the challenges of qualitative judgment enable creation of a multi-objective function for direct music production. Multi-objective fitness functions enable creation of music with varying identifiable styles. With this system we produced …


A Cps-Like Transformation Of Continuation Marks, Kimball Richard Germane Nov 2012

A Cps-Like Transformation Of Continuation Marks, Kimball Richard Germane

Theses and Dissertations

Continuation marks are a programming language feature which generalize stack inspection. Despite its usefulness, this feature has not been adopted by languages which rely on stack inspection, e.g., for dynamic security checks. One reason for this neglect may be that continuation marks do not yet enjoy a transformation to the plain λ-calculus which would allow higher-order languages to provide continuation marks at little cost. We present a CPS-like transformation from the call-by-value λ-calculus augmented with continuation marks to the pure call-by-value λ-calculus. We discuss how this transformation simplifies the construction of compilers which treat continuation marks correctly. We document an …


Bayesian Test Analytics For Document Collections, Daniel David Walker Nov 2012

Bayesian Test Analytics For Document Collections, Daniel David Walker

Theses and Dissertations

Modern document collections are too large to annotate and curate manually. As increasingly large amounts of data become available, historians, librarians and other scholars increasingly need to rely on automated systems to efficiently and accurately analyze the contents of their collections and to find new and interesting patterns therein. Modern techniques in Bayesian text analytics are becoming wide spread and have the potential to revolutionize the way that research is conducted. Much work has been done in the document modeling community towards this end,though most of it is focused on modern, relatively clean text data. We present research for improved …


Javalite - An Operational Semantics For Modeling Java Programs, Saint Oming'o Wesonga Nov 2012

Javalite - An Operational Semantics For Modeling Java Programs, Saint Oming'o Wesonga

Theses and Dissertations

Java is currently a widely used programming language. However, there is no formal definition of Java's semantics. Consequently, Java code does not have a universal meaning. This work discusses recent attempts to formalize Java and presents a new formalism of Java called Javalite. In contrast to common approaches to formalization, Javalite is purely syntactic in its definition. Syntactic operational semantics use the structure of the language to define its behavior. Javalite models most Java features with notable exceptions being threads, reflection, and interfaces. This work presents an executable semi-formal model of Javalite in PLT Redex. Being executable means that Javalite …


Motion Capture Of Character Interactions With A Rope, Bryce Zachary Porter Oct 2012

Motion Capture Of Character Interactions With A Rope, Bryce Zachary Porter

Theses and Dissertations

We present a solution to animating interactions between characters and thin, non-rigid bodies using a passive optical motion capture system. Prior work in human body motion capture can accurately recreate human motion but this work is not adequate because it does not allow for interactions with a non-rigid body. Prior work in face and cloth motion capture handles non-rigid planes but rope is better handled with a curved spline rather than a curved plane. The segmented motion is in the form of un-indexed motion capture data. After segmenting the motion of the thin, non-rigid body and the human character the …


Secure Browser-Based Instant Messaging, Christopher Douglas Robison Sep 2012

Secure Browser-Based Instant Messaging, Christopher Douglas Robison

Theses and Dissertations

Instant messaging is a popular form of communication over the Internet. Statistics show that instant messaging has overtaken email in popularity. Traditionally, instant messaging has consisted of a desktop client communicating with other clients via an instant messaging service provider. However, instant messaging solutions are starting to become available in the web browser–services like Google Talk, Live Messenger and Facebook. Despite the work done by researchers to secure instant messaging networks, little work has been done to secure instant messaging in the browser. We present secure browser-based instant messaging overlays as a means to enable convenient, secure communication in existing …


Automatic Content-Based Temporal Alignment Of Image Sequences With Varying Spatio-Temporal Resolution, Samuel R. Ogden Sep 2012

Automatic Content-Based Temporal Alignment Of Image Sequences With Varying Spatio-Temporal Resolution, Samuel R. Ogden

Theses and Dissertations

Many applications use multiple cameras to simultaneously capture imagery of a scene from different vantage points on a rigid, moving camera system over time. Multiple cameras often provide unique viewing angles but also additional levels of detail of a scene at different spatio-temporal resolutions. However, in order to benefit from this added information the sources must be temporally aligned. As a result of cost and physical limitations it is often impractical to synchronize these sources via an external clock device. Most methods attempt synchronization through the recovery of a constant scale factor and offset with respect to time. This limits …


Automatic Generation Of Music For Inducing Emotive And Physiological Responses, Kristine Perry Monteith Aug 2012

Automatic Generation Of Music For Inducing Emotive And Physiological Responses, Kristine Perry Monteith

Theses and Dissertations

Music and emotion are two realms traditionally considered to be unique to human intelligence. This dissertation focuses on furthering artificial intelligence research, specifically in the area of computational creativity, by investigating methods of composing music that elicits desired emotional and physiological responses. It includes the following: an algorithm for generating original musical selections that effectively elicit targeted emotional and physiological responses; a description of some of the musical features that contribute to the conveyance of a given emotion or the elicitation of a given physiological response; and an account of how this algorithm can be used effectively in two different …


A Confidence-Prioritization Approach To Data Processing In Noisy Data Sets And Resulting Estimation Models For Predicting Streamflow Diel Signals In The Pacific Northwest, Nathaniel Lee Gustafson Aug 2012

A Confidence-Prioritization Approach To Data Processing In Noisy Data Sets And Resulting Estimation Models For Predicting Streamflow Diel Signals In The Pacific Northwest, Nathaniel Lee Gustafson

Theses and Dissertations

Streams in small watersheds are often known to exhibit diel fluctuations, in which streamflow oscillates on a 24-hour cycle. Streamflow diel fluctuations, which we investigate in this study, are an informative indicator of environmental processes. However, in Environmental Data sets, as well as many others, there is a range of noise associated with individual data points. Some points are extracted under relatively clear and defined conditions, while others may include a range of known or unknown confounding factors, which may decrease those points' validity. These points may or may not remain useful for training, depending on how much uncertainty they …


A General Framework For Interactive Television News, Benjamin Bart Sellers Jul 2012

A General Framework For Interactive Television News, Benjamin Bart Sellers

Theses and Dissertations

We design a complete interactive television news system. We develop a news production system that allows for the creation of flexible, content-rich interactive news. This system embraces a general creation process to interactive news that is built on top of a newscast model that evolves from and conforms with the current production newscast model. It allows for content sharing and content reuse. We also create an interactive news viewing system that adapts well to a living room environment. It contains several interactive features designed to give the viewer control and allow them to watch the news when, where, and how …


Detection Likelihood Maps For Wilderness Search And Rescue: Assisting Search By Utilizing Searcher Gps Track Logs, Michael Thomas Roscheck Jul 2012

Detection Likelihood Maps For Wilderness Search And Rescue: Assisting Search By Utilizing Searcher Gps Track Logs, Michael Thomas Roscheck

Theses and Dissertations

Every year there are numerous cases of individuals becoming lost in remote wilderness environments. Principles of search theory have become a foundation for developing more efficient and successful search and rescue methods. Measurements can be taken that describe how easily a search object is to detect. These estimates allow the calculation of the probability of detection—the probability that an object would have been detected if in the area. This value only provides information about the search area as a whole; it does not provide details about which portions were searched more thoroughly than others. Ground searchers often carry portable …


Technique And Cue Selection For Graphical Presentation Of Generic Hyperdimensional Data, Lee Mont Howard Jun 2012

Technique And Cue Selection For Graphical Presentation Of Generic Hyperdimensional Data, Lee Mont Howard

Theses and Dissertations

The process of visualizing n-D data presents the user with four problems: finding a hyperdimensional graphics package capable of rendering n-D data, finding a suitable presentation technique supported by the package that allows insight to be gained, using the provided user interface to interact with the presentation technique to explore the information in the data, and finding a way to share the information gained with others. Many graphics packages have been written to solve the first problem. However, existing packages do not sufficiently solve the other three problems. A hyperdimensional graphics package that sufficiently solves all these problems simplifies the …


Analysis And Design Tools For Structured Feedback Systems, Anurag Rai Jun 2012

Analysis And Design Tools For Structured Feedback Systems, Anurag Rai

Theses and Dissertations

As we begin to analyze and construct extremely complex systems, a theory for understanding and designing the underlying architecture becomes very important. To move in the direction of a precise theory of architecture, this thesis will provide some concrete tools to analyze and design complex systems with a given network structure. The first main result of this thesis analyzes the vulnerability of a system and shows that a system's vulnerability depends on its network structure. We will consider destabilization attacks acting on a single link in a system's logical interconnection structure. The concept of a vulnerable link is characterized and …


Advancing The Effectiveness Of Non-Linear Dimensionality Reduction Techniques, Michael S. Gashler May 2012

Advancing The Effectiveness Of Non-Linear Dimensionality Reduction Techniques, Michael S. Gashler

Theses and Dissertations

Data that is represented with high dimensionality presents a computational complexity challenge for many existing algorithms. Limiting dimensionality by discarding attributes is sometimes a poor solution to this problem because significant high-level concepts may be encoded in the data across many or all of the attributes. Non-linear dimensionality reduction (NLDR) techniques have been successful with many problems at minimizing dimensionality while preserving intrinsic high-level concepts that are encoded with varying combinations of attributes. Unfortunately, many challenges remain with existing NLDR techniques, including excessive computational requirements, an inability to benefit from prior knowledge, and an inability to handle certain difficult conditions …


Improving The Effectiveness Of Machine-Assisted Annotation, Paul L. Felt May 2012

Improving The Effectiveness Of Machine-Assisted Annotation, Paul L. Felt

Theses and Dissertations

Annotated textual corpora are an essential language resource, facilitating manual search and discovery as well as supporting supervised Natural Language Processing (NLP) techniques designed to accomplishing a variety of useful tasks. However, manual annotation of large textual corpora can be cost-prohibitive, especially for rare and under-resourced languages. For this reason, developers of annotated corpora often attempt to reduce annotation cost by offering annotators various forms of machine assistance intended to increase annotator speed and accuracy. This thesis contributes to the field of annotated corpus development by providing tools and methodologies for empirically evaluating the effectiveness of machine assistance techniques. This …


Performance Evaluation Of Optimal Rate Allocation Models For Wireless Networks, Ryan Michael Padilla Apr 2012

Performance Evaluation Of Optimal Rate Allocation Models For Wireless Networks, Ryan Michael Padilla

Theses and Dissertations

Convex programming is used in wireless networks to optimize the sending or receiving rates of links or flows in a network. This kind of optimization problem is formulated into a rate allocation problem, where each node in the network will distributively solve the convex problem and all links or flows will converge to their optimal rate. The objective function and constraints of these problems are represented in a simplified model of contention, interference, and sending or receiving rates. The Partial Interference model is an optimal rate allocation model for use in wireless mesh networks that has been shown to be …


Automated Fingertip Detection, Joseph G. Butler Apr 2012

Automated Fingertip Detection, Joseph G. Butler

Theses and Dissertations

One of the oldest biometrics that has been used to uniquely identify a person is their fingerprint. Recent developments in research on fingerprint collection have made it possible to collect fingerprint data from a stand-off digital image. Each of the techniques developed so far have relied on either a very controlled capture environment to ensure only a single fingertip is collected or manual cropping of the image down to the fingertip. The main body of the research focuses on extracting the fingerprint itself. If fingerprint collection via digital image is ever to be fielded in the real world on such …


Wifu Transport: A User-Level Protocol Framework, Randall Jay Buck Apr 2012

Wifu Transport: A User-Level Protocol Framework, Randall Jay Buck

Theses and Dissertations

It is well known that the transport layer protocol TCP has low throughput and is unfair in wireless mesh networks. Transport layer solutions for mesh networks have been primarily validated using simulations with simplified assumptions about the wireless network. The WiFu Transport framework complements simulator results by allowing developers to easily create and experiment with transport layer protocols on live networks. We provide a user-space solution that is flexible and promotes code reuse while maintaining high performance and scalability. To validate WiFu Transport we use it to build WiFu TCP, a decomposed Tahoe solution that preserves TCP semantics. Furthermore, we …


Improving Filtering Of Email Phishing Attacks By Using Three-Way Text Classifiers, Alberto Trevino Mar 2012

Improving Filtering Of Email Phishing Attacks By Using Three-Way Text Classifiers, Alberto Trevino

Theses and Dissertations

The Internet has been plagued with endless spam for over 15 years. However, in the last five years spam has morphed from an annoying advertising tool to a social engineering attack vector. Much of today's unwanted email tries to deceive users into replying with passwords, bank account information, or to visit malicious sites which steal login credentials and spread malware. These email-based attacks are known as phishing attacks. Much has been published about these attacks which try to appear real not only to users and subsequently, spam filters. Several sources indicate traditional content filters have a hard time detecting phishing …


Infinitesimal Perturbation Analysis For The Capacitated Finite-Horizon Multi-Period Multiproduct Newsvendor Problem, Brigham Bond Wilson Mar 2012

Infinitesimal Perturbation Analysis For The Capacitated Finite-Horizon Multi-Period Multiproduct Newsvendor Problem, Brigham Bond Wilson

Theses and Dissertations

An optimal ordering scheme for the capacitated, finite-horizon, multi-period, multiproduct newsvendor problem was proposed by cite {shao06} using a hedging point policy. This solution requires the calculation of a central curve that divides the different ordering regions and a vector that defines the target inventory levels. The central curve is a nonlinear curve that determines the optimal order quantities as a function of the initial inventory levels. In this paper we propose a method for calculating this curve and vector using spline functions, infinitesimal perturbation analysis (IPA), and convex optimization. Using IPA the derivatives of the cost with respect to …


Feasibility Of Tcp For Wireless Mesh Networks, Richard Lloyd Lee Mar 2012

Feasibility Of Tcp For Wireless Mesh Networks, Richard Lloyd Lee

Theses and Dissertations

When used in a wireless mesh network, TCP has shortcomings in the areas of throughput and fairness among traffic flows. Several methods have been proposed to deal with TCP's weakness in a wireless mesh, but most have been evaluated with simulations rather than experimentally. We evaluate several major enhancements to TCP – pacing, conservative windows, and delayed ACKs – to determine whether they improve performance or fairness in a mesh network operating in the BYU Computer Science building. We also draw conclusions about the effectiveness of wireless network simulators based on the accuracy of reported simulation results.


Using Agent-Based Models To Understand Multi-Operator Supervisory Control, Yisong Guo Mar 2012

Using Agent-Based Models To Understand Multi-Operator Supervisory Control, Yisong Guo

Theses and Dissertations

As technology advances, many practical applications require human-controlled robots. For such applications, it is useful to determine the optimal number of robots an operator should control to maximize human efficiency given different situations. One way to achieve this is through computer simulations of team performance. In order to factor in various parameters that may affect team performance, an agent-based model will be used. Agent-based modeling is a computational method that enables a researcher to create, analyze, and experiment with models composed of agents that interact within an environment [12]. We construct an agent-based model of humans interacting with robots, and …


Analysis And Characterization Of Author Contribution Patterns In Open Source Software Development, Quinn Carlson Taylor Mar 2012

Analysis And Characterization Of Author Contribution Patterns In Open Source Software Development, Quinn Carlson Taylor

Theses and Dissertations

Software development is a process fraught with unpredictability, in part because software is created by people. Human interactions add complexity to development processes, and collaborative development can become a liability if not properly understood and managed. Recent years have seen an increase in the use of data mining techniques on publicly-available repository data with the goal of improving software development processes, and by extension, software quality. In this thesis, we introduce the concept of author entropy as a metric for quantifying interaction and collaboration (both within individual files and across projects), present results from two empirical observational studies of open-source …


Commit Patterns And Threats To Validity In Analysis Of Open Source Software Repositories, Alexander Curtis Maclean Feb 2012

Commit Patterns And Threats To Validity In Analysis Of Open Source Software Repositories, Alexander Curtis Maclean

Theses and Dissertations

In the course of studying the effects of programming in multiple languages, we unearthed troubling trends in SourceForge artifacts. Our initial studies suggest that programming in multiple languages concurrently negatively affects developer productivity. While addressing our initial question of interest, we discovered a pattern of monolithic commits in the SourceForge community. Consequently, we also report on the effects that this pattern of commits can have when using SourceForge as a data-source for temporal analysis of open source projects or for studies of individual developers.


Computer Aided Geometric Design, Thomas W. Sederberg Jan 2012

Computer Aided Geometric Design, Thomas W. Sederberg

Faculty Publications

This semester is the twenty-fourth time I have taught a course at Brigham Young University titled, "Computer Aided Geometric Design." When I first taught such a course in 1983, the field was young enough that no textbook covered everything that I wanted to teach, and so these notes evolved. The field now has matured to the point that several semesters worth of valuable material could be compiled. These notes, admittedly biased towards my own interests, reflect my personal preferences as to which of that material is most beneficial to students in an introductory course. I welcome anyone who has an …


A Synthetic Document Image Dataset For Developing And Evaluating Historical Document Processing Methods, Daniel Walker, William Lund, Eric Ringger Jan 2012

A Synthetic Document Image Dataset For Developing And Evaluating Historical Document Processing Methods, Daniel Walker, William Lund, Eric Ringger

Faculty Publications

Document images accompanied by OCR output text and ground truth transcriptions are useful for developing and evaluating document recognition and processing methods, especially for historical document images. Additionally, research into improving the performance of such methods often requires further annotation of training and test data (e.g., topical document labels). However, transcribing and labeling historical documents is expensive. As a result, existing real-world document image datasets with such accompanying resources are rare and often relatively small. We introduce synthetic document image datasets of varying levels of noise that have been created from standard (English) text corpora using an existing document degradation …