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...
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...
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...
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...
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...
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...
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....
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...
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...
Generating solutions to Sokoban levels is an NP-hard problem that is difficult for even modern day computers to solve due to its complexity. This project explores the creation of a Sokoban solver by eliminating as many potential moves as possible to greatly limit the overall search space. This reduction is...
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...
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...
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...
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,...