A relatively new model of error control is the limited magnitude error over high radix channels. In this error model, the error magnitude does not exceed a certain limit known beforehand. In this dissertation, we study systematic error control codes for common channels under the assumption that the maximum error...
This paper provides a measurement-based performance evaluation of the Optimized Link State Routing (OLSR) protocol. Two versions of OLSR, OLSR-ETX and OLSR-ETT, are implemented and evaluated on a mesh network that we built from off-the-shelf commercial components. OLSR-ETX uses the Expected Transmission Count (ETX) metric whereas, OLSR-ETT uses the Expected...
Visual information presented in diagrams promotes information processing both in an individual and in collaborative work. Previous literature has identified the role of diagrams in
understanding information processing in a variety of disciplines. In software engineering, diagrams are a prevalent method involved in process development: diagrams are used for system...
Monte-Carlo planning algorithms such as UCT make decisions at each step by
intelligently expanding a single search tree given the available time and then
selecting the best root action. Recent work has provided evidence that it can be
advantageous to instead construct an ensemble of search trees and make a...
While there are many ways to evaluate a user interface design, the user's mental workload and situation awareness (SA) are particularly important considerations in the supervisory control of safety-critical systems. Typically, operators of these systems must monitor high-volume, time-sensitive status information. Interface design for this domain can be challenging and...
Asymmetric tensor fields are useful for understanding fluid flow and solid deformation. They present new challenges, however, for traditional tensor field visualization techniques such as hyperstreamline placement and glyph packing. This is because the physical behavior of tensors inside real domains where eigenvalues are real is fundamentally different from the...
3D object recognition is a very difficult and important problem in computer vision, arising in a wide range of applications. Typically in 3D object recognition, interest points are extracted from images and then matched. A shortcoming of this approach is that points only carry local visual information. Therefore, there
could...
In text classification, labeling features is often less time consuming than labeling entire documents. In situations where very little labeled training data is available, feature relevance feedback has the potential to dramatically increase classification performance. We review previous work on incorporating feature relevance feedback in the form of labeled features...
This dissertation explores algorithms for learning ranking functions to efficiently solve search problems, with application to automated planning. Specifically, we consider the frameworks of beam search, greedy search, and randomized search, which all aim to maintain tractability at the cost of not guaranteeing completeness nor optimality. Our learning objective for...
Trends in wireless networks are increasingly pointing towards a future with multi-hop
networks deployed in multi-channel environments. In this thesis, we present the design
for iMAC—a protocol targeted at medium access control in such environments. iMAC
uses control packets on a common control channel to faciliate a three-way handshake
between...
Keeping FOSS developers motivated is a challenging problem, and their motivation levels can affect the team's productivity and satisfaction, leading to higher or lower productivity. Using reputation systems as a motivator has become the de-facto standard for many online communities, rewarding user's activity through badges of honor or achievement levels....
The gradient of a velocity vector field is an asymmetric tensor field which can provide critical insight that is difficult to infer from traditional trajectory-based vector field visualization techniques. I describe the structures in the eigenvalue and eigenvector fields of the gradient tensor and how these structures can be used...
This study introduces a layered model for rendering human teeth. Human teeth exhibit complex light interaction due to their layered structure. While the lighting responses of teeth have been studied in the dental industry for the production of realistic looking dentures, to our knowledge this is the first study of...
Since free riders in P2P network reduce the system's performance, how to maintain and encourage the nodes' cooperation is an important aspect of P2P related research. In this thesis, a P2P system is modeled based on two games: stag hunt game and snowdrift game. To relate the model to the...
For building robust software applications, it is important for the software engineer to make efficient use of the available building blocks. Learning the basic language constructs is only the first step in this process. It is becoming increasingly important for software engineers, especially students, to get acquainted with the available...
We present the evolution of a reasoning system for inferring dimension information in
spreadsheets. The three papers included in this thesis show how the initial system can be
used to check the consistency of spreadsheet formulas and thus is able to detect errors in
spreadsheets, and the evolution to a...
Dimensionality reduction (DR) is an efficient approach to reduce the size of
data by capturing the informative intrinsic features and discarding the noise. DR
methods can be grouped through a variety of categories, e.g. supervised/ unsupervised,
linear/non-linear or parametric/non-parametric. Objective function based
methods can be grouped into convex and non...
Parallel processors are classified into two classes: shared-memory multiprocessors and distributed- memory multiprocessors. In the shared-memory system, processors communicate through a common memory unit. However, in the distributed multiprocessor system, each processor has its own memory unit and the communications among the processors are performed through an interconnection network. Thus,...
This dissertation addresses two fundamental problems in computer vision—namely,
multitarget tracking and event recognition in videos. These problems are challenging
because uncertainty may arise from a host of sources, including motion blur,
occlusions, and dynamic cluttered backgrounds. We show that these challenges can be
successfully addressed by using a multiscale,...
This dissertation addresses a number of inter-related and fundamental problems in computer vision. Specifically, we address object discovery, recognition, segmentation, and 3D pose estimation in images, as well as 3D scene reconstruction and scene interpretation. The key ideas behind our approaches include using shape as a basic object feature, and...
Visual programming languages (VPLs) have been widely used to support end-user programming. However, end users are still not able to reuse code as actively as professional programmers, even when given abundant resources such as a large VPL program repository. One reason may be that current VPL development environments lack features...
Beaversource provides both code-hosting tools and social networking in one place. Students and faculty at Oregon State University have been using Beaversource to host their projects, both for classwork and research. Several usability problems were reported in a survey conducted on Beaversource last year. Some of these issues were severe...
Free/Open Source Software (FOSS) is a powerful development paradigm for
creating software. Increasingly more FOSS projects, like Firefox and Android, are
integrated into mainstream technology. It is important that FOSS projects serve its
diverse user base well. Several surveys have found that existing FOSS communities
are very homogenous populations and...
The Internet is growing rapidly in terms of websites, users and uses. People use the Internet for reference, shopping, social networking, communications, business and much more. Though the Internet is useful, there are many risks associated with its use, like malicious websites, identity theft, hateful content and fraudulent practices. Online...
A distributed system is a network of multiple autonomous computational nodes designed primarily for performance scalability and robustness. The performance of a distributed system depends critically on how tasks and resources are distributed among the nodes. Thus, a main thrust in distributed system research is to design schemes for distributing...
Acting intelligently to efficiently solve sequential decision problems requires the ability to extract hierarchical structure from the underlying domain dynamics, exploit it for optimal or near-optimal decision-making, and transfer it to related problems instead of solving every problem in isolation. This dissertation makes three contributions toward this goal.
The first...
Within the past several years the technology of high-throughput sequencing has transformed the study of biology by offering unprecedented access to life's fundamental building block, DNA. With this transformation's potential a host of brand-new challenges have emerged, many of which lend themselves to being solved through computational methods. From de...
Experimental game theory is the use of game theoretic abstractions—games, players, and strategies—in experiments and simulations. It is often used in cases where traditional, analytical game theory fails or is difficult to apply. This thesis collects three previously published papers that provide domain-specific language (DSL) support for defining and executing...
In a software development cycle, programs go through many iterations. Identifying and
understanding program changes is a tedious but necessary task for programmers, especially when
software is developed in a collaborative environment. Existing tools used by the programmers
either lack in finding the structural differences, or report the differences as...
While there are powerful keyword search systems that index all kinds of resources including emails and web pages, people have trouble recalling semantic facts such as the name, location, edit dates and keywords that uniquely identifies resources in their personal repositories. Reusing information exasperates this problem. A rarely used approach...
Free/Open Source Software (FOSS) communities often use open bug reporting to allow users to participate by reporting bugs. This practice can lead to more duplicate reports, as inexperienced users can be less rigorous about researching existing bug reports. The purpose of this research is to determine the extent of this...
The meteoric rise and prevalent usage of wireless networking technologies for mobile
communication applications have captured the attention of media and imagination of
public in the recent decade. One such proliferation is experienced in Wireless Sensor
Networks (WSNs), where multimedia enabled elements are fused with integrated
sensors to empower tightly...
A fundamental problem in computer vision is to partition an image into meaningful segments. While image segmentation is required by many applications, the thesis focuses on segmentation of computed tomography (CT) images for analysis and quality control of composite materials. The key research contribution of this thesis is a novel...
It is possible to purchase, for as little as $10,000, a cluster of computers with the capability to rival the supercomputers of only a few years ago. Now, users that have little to no experience developing distributed applications or managing a cluster are in a position to do so. To...
Streaming media and interactive television viewing experiences are becoming more commonplace with the introduction of services such as Netflix Streaming, the Apple TV, and Google TV aided by the increase adoption of broadband internet. As these services make their way into the living room, and developers struggle to accommodate more...
Application Programming Interfaces (APIs) enable software developers to utilize and create functionality that would otherwise take a lot of time and effort to build from scratch. Consequently, an essential part of software engineering training is for students to learn how to use APIs effectively. The existing jTutors system enables an...
In this work, I examine the problem of understanding American football in video. In particular, I present several mid-level computer vision algorithms that each accomplish a different sub-task within a larger system for annotating, interpreting, and analyzing collections of American football video. The analysis of football video is useful in...
There is a growing interest in bringing online and streaming content to the television. Gaming platforms such as the PS3, Xbox 360 and Wii are at the center of this digital convergence; platforms for accessing new media services. This presents a number of interface challenges, as controllers designed for gaming...
Spreadsheets are a widely used end-user programming tool. Field audits have found that 80-90% of spreadsheets created by end users contain textual and formula errors in spreadsheets. Such errors may have severe negative consequences for users in terms of productivity, credibility, or profits. To solve the problem of spreadsheet errors,...
Networks of distributed, remote sensors are providing ecological scientists with a view of our environment that is unprecedented in detail. However, these networks are subject to harsh conditions, which lead to malfunctions in individual sensors and failures in network communications. This behavior manifests as corrupt or missing measurements in the...
Researchers/engineers in the field of software testing have valued coverage as a testing metric for decades now. There have been various empirical results that have shown that as coverage increases the ability of the test program to detect a fault also increases. As a result numerous coverage techniques have been...
This project explores a security framework, called the Persona Concept, aimed at giving the user greater control over their private data in cyberspace, in particular, their electronic credentials. The background for the Persona Concept, along with the requirements identified can be found in three (3) technical publications produced by Kal...
This project addresses the problems of manually placing facial landmarks on a portrait and finding a fast way to warp the annotated image of a face. While there are many approaches to automatically find facial landmarks, most of them provide insufficient results in uncontrolled environments. Thus I introduce a method...
Programmers often have to choose components online for reuse based on software quality. To help with this choice, most component repositories (SourceForge, CodeProject, etc.) provide information such as user ratings and reviews of components. However, the reusability of components is not immediately obvious from
this material. To make things worse,...
Bayesian Optimization (BO) methods are often used to optimize an unknown function f(•) that is costly to evaluate. They typically work in an iterative manner. In each iteration, given a set of observation points, BO algorithms select k ≥ 1 points to be evaluated. The results of those points are...
The study of physical activity is important in improving people’s health as it can help people understand the relationship between physical activity and health. Accelerometers, due to its small size, low cost, convenience and its ability to provide objective information about the frequency, intensity, and duration of physical activity, has...
How can an agent generalize its knowledge to new circumstances? To learn
effectively an agent acting in a sequential decision problem must make intelligent action selection choices based on its available knowledge. This dissertation focuses on Bayesian methods of representing learned knowledge and develops novel algorithms that exploit the represented...
The topic of species distribution modelling has been on of increasing interest in
recent years. As climate change is becoming of even more interest to researchers,
more tools are needed to better analyze and predict various climate change scenarios.
One particular area of interest is that of species distribution modeling....
This project presents a new, and more versatile, method for performing Relief Mapping (also known as Parallax Occlusion Mapping), utilizing rates of change in texture coordinates across a polygon surface to calculate the texture sampling offsets used in the ray-tracing portion of the Relief Mapping algorithm. This new technique relies...
This thesis presents an efficient computational voxelization approach that utilizes the graphics pipeline. Our approach is hybrid in that it performs a precise gap-free computational voxelization, employs fixed-function components of the GPU, and utilizes the stages of the graphics pipeline to improve parallelism. This approach makes use of the latest...