Bruce F. Naylor

University of Texas at Austin | UT · center for computational biology and bioinformatics

Background: Posttraumatic stress disorder (PTSD) is a significant burden among combat Veterans returning from the wars in Iraq and Afghanistan. While empirically supported treatments have demonstrated reductions in PTSD symptomatology, there remains a need to improve treatment effectiveness. Functional magnetic resonance imaging (fMRI) neurofeedba...

Three-dimensional interactive virtual environments (VEs) are a powerful tool for brain-imaging based cognitive neuroscience that are presently under-utilized. This paper presents machine-learning based methods for identifying brain states induced by realistic VEs with improved accuracy as well as the capability for mapping their spatial topography...

Binary Space Partitioning Trees (BSP-Trees) have been proposed as an alternative way to represent polytopes based on the spatial subdivision paradigm. Algorithms that convert from Boundary Representation (BRep) to BSP-Trees have been proposed, but none is known to perform the opposite conversion. In this paper we present such an algorithm, that tak...

The extension from interactive 2D wireframe geometry to interactive solid geometry has been for sometime one of the goals of Computer Graphics. Our approach to this objective is the utilization of a computational representation of geometric sets that we believe is better suited to geometric computation than alternatives inherited from mathematics....

Partitioning trees, a multi-dimensional generalization of binary search trees, is alone among the principal methods for representing geometry in combining the representation of a set with the geometric search structure required for efficient spatial operations such as set operations and visibility. Since a partitioning tree may be interpreted as sp...

While almost all research on image representation has assumed an underlying discrete space, the most common sources of images have the structure of the continuum. Although employing discrete space representations leads to simple algorithms, among its costs are quantization errors, significant verbosity and lack of structural information. A neglecte...

The discrete space representation of most scientific datasets, generated through instruments or by sampling continuously defined fields, while being simple, is also verbose and structureless. We propose the use of a particular spatial structure, the binary space partitioning tree as a new representation to perform efficient geometric computation in...

Binary Space Partitioning Trees (BSP-Trees) have been proposed as an alternative way to represent polytopes based on the spatial subdivision paradigm. Algorithms that convert from Boundary Representation (BRep) to BSP-Trees have been proposed, but none is known to perform the opposite conversion. In this paper we present such an algorithm, that tak...

We present a system for efficient prediction of RF power distribution in site specific environments using a variation of ray tracing, which we called ray-beam tracing. The simulation results were validated against measured data for a number of large environments with good statistical correlation between the two. We represent geometric environments...

While a very effective method for designing objects is to describe their surfaces using non-linear parametric representations, these are not necessarily the best for executing all of the computations required for modeling and rendering. These computations include set operations for CSG, collision detection, ray-surface intersections, visible surfac...

Current state-of-the-art augmented reality systems simply overlay computer-generated visuals on the real-world imagery, for example via video or optical see-through displays. However, overlays are not effective when displaying data in three dimensions, ...

The cylindrical banyan network is a variation of the classical banyan network in two ways: (1) each node is a processor with a switch, and (2) every pair of nodes at the two ends is merged. We present a routing algorithm for the cylindrical banyan network, and show it is optimal in terms of the path length. We also show that for the cylindrical ban...

The binary space partitioning tree is a method of converting a discrete space representation to a particular continuous space representation. The conversion is accomplished using standard discrete space operators developed for edge detection, followed by a Hough transform to generate candidate hyperplanes that are used to construct the partitioning...

The extension from interactive 2D wireframe geometry to interactive solid geometry has been for sometime one of the goals of Computer Graphics. Our approach to this objective is the utilization of a computational representation of geometric sets that we believe is better suited to geometric computation than alternatives inherited from mathematics....

Generating piecewise linear approximations of digitized or “densely sampled” curves is an important problem in many areas. Here, we consider how to approximate an arbitrary digitized 3-D space curve, made of n+1 points, with m line segments. We present an O(n 3 log m) time, O(n 2 log m) space, dynamic programming algorithm which finds an optimal ap...

BSP trees have been shown to provide an effective representation of polyhedra through the use of spatial subdivision, and are an alternative to the topologically based b-reps. While bsp tree algorithms are known for a number of important operations, such as rendering, no previous work on bsp trees has provided the capability of performing boolean s...

Sculpt, an interactive polyhedral solid modeling system, combines the effectiveness of BSP trees for performing geometric search, set operations and determination of visibility, with the rendering performance of the AT&T Pixel Machines to provide interactive sculpt of texture mapped solids. The paradigm presented to the user is one in which a tool...

The search for better representations of geometric objects has produced as a candidate Binary Space Partitioning Trees (BSP trees). By simply subdividing space recursively hyperplanes into cells, any linear semi-algebraic set, e.g. polytopes, can be represented by a binary tree. Yet the algorithms operating on this representation are unaffected by...

BSP trees have been shown to provide an effective representation of polyhedra through the use of spatial subdivision, and are an alternative to the topologically based b-reps. While bsp tree algorithms are known for a number of important operations, such as rendering, no previous work on bsp trees has provided the capability of performing boolean s...

This paper describes a new algorithm for solving the hidden surface (or line) problem, to more rapidly generate realistic images of 3-D scenes composed of polygons, and presents the development of theoretical foundations in the area as well as additional related algorithms. As in many applications the environment to be displayed consists of polygon...

We introduce a new representation for polyhedra by showing how Binary Space Partitioning Trees (BSP trees) can be used to represent regular sets. We then show how they may be used in evaluating set operations on polyhedra. The BSP tree is a binary tree representing a recursive partitioning of d-space by (sub-)hyperplanes, for any dimension d. Their...

Earliest research on solid bsp trees. Combines ray-tracing with constructive solid geometry. Work was done at Georgia Tech in 1985.

Any set of linear maps (affine transformations) and an associated set of probabilities determines an Iterated Function System (IFS). Each IFS has a unique 'attractor' which is typically a fractal set (object). Specification of only a few maps can produce very complicated objects. Design of fractal objects is made relatively simple and intuitive by...

In computer graphics, geometric modeling of complex objects is a difficult process. An important class of complex objects arise from natural phenomena: trees, plants, clouds, mountains, etc. Researchers are investigating a variety of techniques for extending modeling capabilities to include these as well as other classes. One mathematical concept t...

The principal calculation performed by all visible surface algorithms is the determination of the visible polygon at each pixel in the image. Of the many possible speedups and efficiencies found for this problem, only one published algorithm (developed almost a decade ago by a group at General Electric) took advantage of an observation that many vi...

Thesis (Ph. D.)--University of Texas at Dallas, 1981. Includes vita. Includes bibliographical references (leaves 161-163). Typescript (photocopy).