Wave energy converters (WECs) show promising potential to significantly contribute to global renewable energy goals. Numerous WEC designs have been proposed and investigated, but wave energy conversion technology has yet to reach convergence in the same way wind or solar has. Of the designs currently in existence, surface-piercing WECs are...
Bicyclist safety at urban intersections is a critical element for encouraging an increase in bicycle commuting. With bicycle injury and fatality rates rising due to collisions with vehicles at signalized intersections, increasing the safety of riders continues to be an important consideration when promoting this mode of transportation. Previous research...
Heterogeneous catalytic reactions in solvents are important for chemical processes like direct methanol fuels, biomass conversion to biofuels and electrochemical reduction of CO2 to fuels. Numerous experimental studies have shown that co-adsorbates and solvents affect the rate and selectivity of heterogeneous catalytic reaction, therefore fundamental understanding of how co-adsorbates and...
Graphics of hair have been constantly improved since Kajiya’s famous teddy bear in 1989. By combining these concepts and real-world physics laws, I created a realistic representation of hair on a sphere-shaped head. OpenGL also provides a constantly updated display to continuously render the graphic. Using springs, the hair can...
An important problem in computer graphics is to determine where contour lines and ridges appear in a surface constructed from a triangle mesh. In this presentation we will investigate a new answer to this problem – the horizon measure. The horizon measure determines the likelihood of contour lines to appear...
In this dissertation, we use Fourier-analytic and spectral theory methods to analyze the behavior of solutions of the incompressible Navier-Stokes equations in 2D and 3D (with an eye towards better understanding turbulence). In particular, we investigate the possible existence of so-called ghost solutions to the Navier-Stokes Equations. Such solutions, if...
Numerical results are presented using a higher-order pseudo-spectral method in order to solve the Zakharov-Craig-Sulem formulation of the Euler model. We study the effects of variable bathymetry on weakly-dispersive, weakly-nonlinear, shallow water waves. Improved predictions on wave amplitude and shoaling behavior are developed by analytical means in the context of...
This dissertation provides a comparison of statistical and econometric frameworks, using a previously unused freight data source, to study crash frequency by crash type and heavy-vehicle hard braking in Oregon. Hard braking can serve as a proxy for several factors, one of which is safety. Therefore, with the hard braking...
3D volume segmentation is a fundamental process in many scientific and medical applications. Producing accurate segmentations, in an efficient way, is challenging, in part due to low imaging data quality (e.g., noise and low image resolution), and ambiguity in the data that can only be resolved with higher-level knowledge of...
Variability is an important and widely studied topic across domains such as version control, software product lines, and metaprogramming. This dissertation presents an investigation into the process of systematically adding variability to data structures and programs, leading to guidelines for variational data structures and implications for programs that create, manipulate,...
”Until relatively recently, mankind was not aware that there was a separable binocular depth sense. Through the ages, people like Euclid and Leonardo understood that we see different images of the world with each eye. But it was Wheatstone who in 1838 explained to the world, with his stereoscope and...
In many traditional computer graphics applications, rendered scenes typically utilize 3D meshes to represent objects within an environment. As the demand to further improve the realism of graphics applications increases, such as for movies and games, it is becoming more important to represent the inner volumes of object meshes. In...
In this thesis I will look at a definition of computable randomness from Algorithmic Information Theory as defined by Andre Nies through the lens of Computable Analaysis asdefined by Klaus Weihrauch. I will show that despite the fact that these two paradigmsgenerate distinct classes of computable supermartingales, the class of...
This dissertation addresses the problem of semantic labeling of image pixels. In the course of our work, we considered different types of semantic labels, including object classes (e.g., car, person), 3D depth values (in the range 0 to 80 meters), and affordance classes (e.g., walkable, sittable). Semantic pixel labeling is...
This thesis provides a comparison of advanced econometric frameworks to account for unobserved factors in crash reported data (also referred to as unobserved heterogeneity) while identifying contributing factors by roadway classification for heavy vehicle injury severity and crash rates. The presented thesis provides two manuscripts that expand the literature regarding...
In the light of the changing climate, the importance of designing effective watershed management plans that are likely to be implemented is becoming ever more important. This research introduces a new concept, consensus, for incorporation into stakeholder-guided interactive optimization of watershed management plans. User preferences were mathematically simulated based upon...
Recognizing human actions in videos is a long-standing problem in computer vision with a wide range of applications including video surveillance, content retrieval, and sports analysis. This thesis focuses on addressing efficiency and robustness of video classification in unconstrained real-world settings. The thesis work can be broadly divided into four...
Visualizing large movement datasets with flow maps is difficult because overlapping flows create significant graphical conflicts that make accurate interpretation difficult or impossible. Interactive flow mapping applications allow users to explore large movement datasets by automatically generating flow maps from subsets of the data in response to queries by the...
In this thesis, the effectiveness of the 100 percent + XX percent seismic response directional combination rule available in codes and standards is evaluated using simulated nonlinear seismic response of two existing multi-story reinforced concrete plan-irregular buildings. The 5-story and 8-story buildings were designed according to the 1975 seismic codes...
The Intel Xeon Phi is a relative newcomer to the scientific computing scene. In the recent years, GPUs have been used extensively for mathematical simulations. The Xeon Phi is Intel’s response to the use of these cards. Like the GPU, it is highly parallelizable but can be programmed like a...
Given k terminal pairs (s₁,t₁),(s₂,t₂),..., (s[subscript k],t[subscript k]) in an edge-weighted graph G, the k Shortest Vertex-Disjoint Paths problem is to find a collection P₁, P₂,..., P[subscript k] of vertex-disjoint paths with minimum total length, where P[subscript i] is an s[subscript i]-to-t[subscript i] path. As a special case of the...
Modeling tire-snow interaction is important in designing effective snow tires, which directly affects road safety during wintry weather. Unfortunately, tires have complex tread designs and the physical properties of snow have not been characterized. We employ the Material Point Method (MPM) for simulating a material that mimics the fracturing and...
In this thesis we study a numerical analysis problem motivated by the need to simulate an event such as an oil spill in a deep water environment. Numerical simulation can help to mitigate the disastrous effects of such events by aiding the management of risk assessment and recovery efforts.
However,...
Graphics hardware in mobile devices has become more powerful, allowing rendering techniques such as ray-cast volume rendering to be done at interactive rates. This increase of performance provides desktop capabilities combined with the portability of a tablet. Volumes can demand a high amount of memory in order to be loaded...
As the nonstop advancement of graphics hardware continues, new features are being added to the graphics pipeline on a regular basis. One of these advancements is called Pixel Synchronization, which allows a graphics programmer more power with certain types of data structures that may be accessed by multiple shader units...
During the 2011 Great East Japan Earthquake and Tsunami, numerous bridge structures were damage or destroyed. The damage to bridge systems was caused by long duration strong ground shaking, tsunami inundation forces, or both. Long duration strong ground shaking from subduction zone earthquakes and the multi-hazard scenario of combined earthquake...
This thesis presents an interactive software tool for tracking a moving object in a video. In particular, we focus on the problem of tracking a player in American football videos. Object tracking is one of the fundamental problems in computer vision. It is one of the most important components in...
This dissertation addresses the problem of recognizing human activities in videos. Our focus is on activities with stochastic structure, where the activities are characterized by variable space-time arrangements of actions, and conducted by a variable number of actors. These activities occur frequently in sports and surveillance videos. They may appear...
This thesis addresses a fundamental computer vision problem, that of action recognition. The goal of action recognition is to recognize a class of human actions in a given video. Action recognition has a wide range of applications, including automated surveillance, sports video analysis, internet-based searches etc. The main challenge is...
Realistic (ideally photorealistic) real-time rendering has remained an elusive goal in computer graphics. While photorealistic rendering has certainly been achieved at the expense of tremendous computational resources and corresponding rendering times; real-time rendering typically must accept a great number of compromises to achieve adequate performance, such as aliasing artifacts, the...
The study of the diversity of multivariate objects shares common characteristics across disciplines, including ecology and organizational management. Nevertheless, experts in these two disciplines have adopted somewhat separate diversity concepts and analysis techniques, limiting the ability of potentially sharing and cross comparing these concerns. Moreover, while complex diversity data may...
To better understand the extreme local amplification of tsunami, the experimental investigation on counter-propagating solitary wave collisions over a horizontal bottom was conducted using the optical measurement techniques: Particle Image Velocimetry (PIV), and Laser Induced Fluoresce (LIF). Head-on collisions and oblique collisions of equal-amplitude as well as unequal-amplitude waves were...
Worst-case analysis is often meaningless in practice. Some problems never reach the anticipated worst-case complexity. Other solutions get bogged down with impractical constants during implementation, despite having favorable asymptotic running times. In this thesis, we investigate these contrasts in the context of finding maximum flows in planar digraphs. We suggest...
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...
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...
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...
Proper use of vegetation in streambank bioengineering practices requires a comprehensive understanding of the influence of vegetation density on streambank hydraulics. A series of studies were conducted to investigate the relationship between independent variables vegetation density, bank angle, and discharge and dependent variables channel velocity, resistance, turbulence, and shear stress....
Virtual environments and simulations are being used increasingly to both visualize and understand data as well as to create scenarios for training and analysis purposes. In this paper, we are interested in the use of simulation and visualization of interactive virtual agents to create realistic motions for training scenarios. We...
This thesis addresses numerical simulation of flow maldistribution in microchannels. Microchannels are often associated with two phase-flows which can generate many problems such as plugging the channel or perturbing the flow. In this study we have used CFD and fully resolved technique to simulate what would happen in the case...
At the start of the 21st century much of the focus of aircraft design has been turned to unmanned aerial vehicles (UAVs) which generally operate at much lower speeds in higher risk areas than manned aircraft. One subset of UAVs are Micro Air Vehicles (MAVs) which usually are no larger...
Flow separation is an important phenomenon in fluid dynamics because of the effect it has on lift and drag on immersed bodies. Areas of swirl within a separated flow region may have a distinct effect on the surface forces, modifying the lift and drag characteristics. A correlation between the passage...
Cellular sets in the Hilbert cube are the intersection of nested sequences of normal
cubes. One way of getting cellular maps on the Hilbert cube is by decomposing the Hilbert
cube into cellular sets and using a quotient map. By using a cellular decomposition of the
Hilbert cube, an example...
A basic tradeoff to consider when designing a distributed data-mining framework is the need for a compromise between the cost of communication and computation resources and the accuracy of the mining results. This is essentially a decision of whether it is more efficient to communicate all of the data to...
The Line Integral Convolution (LIC) is a mainstay of flow visualization. It is, however, computationally intensive, which limits its interactivity. Also, when used to view three-dimensional (3D) vector fields, the resulting images are dense and cluttered, making it difficult to perceive the flow on the interior parts of the field....
Traditional application of Voronoi diagrams for space partitioning creates Voronoi regions, with areas determined by the generators’ relative locations and weights. Especially in the area of information space (re)construction, however, there is a need for inverse solutions; i.e., finding weights that result in regions with predefined areas. In this thesis,...
We present an approach for generating a character’s response in anticipation of an impending impact. Protective anticipatory movement is built upon several simple actions that have been identified as response mechanisms in monkeys and in humans. These actions are parameterized by a model of the interaction based on the approaching...
The high cost of manually producing background characters creates a demand for a
way to automatically generate plausible behaviors. These background extras need to
behave in a manner that is believable such that they do not distract the focus of the
audience from the primary action occurring in the scene....