CS Theses & Dissertations 2001

For 2001 graduation dates (in alphabetical order by last name):

Fast Solvers for time-Harmonic Maxwell's Equations in 3D
Aruliah, Dhavide Arjunan
URI : http://hdl.handle.net/2429/13522
Degree : Doctor of Philosophy - PhD
Graduation Date : 2001-11
Supervisor : Dr. Ascher

The speed of iterative solvers for discretizations of partial differential equations (PDEs) is a significant bottleneck in the performance of codes designed to solve large-scale electromagnetic inverse problems. A single data inversion requires solving Maxwell's equations dozens if not hundreds of times. An inherent difficulty in geophysical contexts is that the conductivity and permeability coefficients may exhibit discontinuities spanning several orders of magnitude. Furthermore, in the air, the conductivity effectively vanishes. In standard formulations of Maxwell's equations, the curl operator that dominates the PDE operator leads to strong mixing of field components and illconditioning of linear systems resulting from standard discretizations. The primary objective of this research is to build fast iterative solvers for the forward-modeling problem associated with electromagnetic inverse problems in the frequency domain. Toward this goal, a Helmholtz decomposition of the electric field using a Coulomb gauge condition recasts the PDE problem in terms of scalar and vector potentials. The resulting indefinite system is then stabilized by addition of a vanishing term that lies in the kernel of the dominant curl operator. Finally, an extra differentiation recasts the PDE system in a diagonally-dominant form reminiscent of a "pressure-Poisson" formulation for incompressible fluid flow. The continuous PDE problem obtained is equivalent to the original Maxwell's system but has a structure that is amenable to reliable solution techniques. Using a finite-volume scheme, the PDE is discretized on a staggered grid in three dimensions. The discretization obtained possesses conservation properties typical of finite-volume methods. Furthermore, interface conditions imposed by discontinuities in the material coefficients are sensibly accounted for in deriving the discretization. Although the simple representation of the media on a Cartesian tensor-product grid uses staircase approximations of surfaces of discontinuity of the material coefficients, some analysis and a numerical study demonstrate the suitability of such coarse approximations for diffusive problems. The discretization yields a non-Hermitian sparse linear system of algebraic equations; various preconditioners for Krylov-subspace methods are described, analyzed, implemented, and tested. Of particular interest is a multigrid preconditioner that exploits both the structure of the PDE problem and the availability of well-established solvers for elliptic PDE problems (in particular, Dendy's BOXMG solver). The end result is a robust solver for the forward-modeling equations that can be incorporated within a competitive inverse problem code.

Eigenvector Radiosity
Ashdown, Ian
URI : http://hdl.handle.net/2429/11575
Degree : Master of Science - MSc
Graduation Date : 2001-05
Supervisor : Dr. Heidrich

On creating a student model to assess effective exploratory behaviour in an open learning environment
Bunt, Andrea Katharine
URI : http://hdl.handle.net/2429/11648
Degree : Master of Science - MSc
Graduation Date : 2001-11
Supervisor : Dr. Conati

Performance Improvements for BFS
Carton, Ross Walker
URI : http://hdl.handle.net/2429/11658
Degree : Master of Science - MSc
Graduation Date : 2001-11
Supervisor : Dr. Feeley

High-level cycle-accurate specification of microprocessors
Chang, Felix Sheng-Ho
URI : http://hdl.handle.net/2429/11666
Degree : Master of Science - MSc
Graduation Date : 2001-11
Supervisor : Dr. Hu

A security architecture for mobile agent systems
Fu, Peng
URI : http://hdl.handle.net/2429/11716
Degree : Master of Science - MSc
Graduation Date : 2001-11
Supervisor : Dr. Vuong

Resource Discovery in Wide Area Networks
Godin, Bruno
Master’s essay available in print and online : https://bibrrs.library.ubc.ca/vwebv/holdingsInfo?bibId=129423
Degree : Master of Science - MSc
Graduation Date : 2001-11
Supervisor : Dr. Hutchinson

The MPI Implementation on Net VM
Gu, Yanping
URI : http://hdl.handle.net/2429/11299
Degree : Master of Science - MSc
Graduation Date : 2001-05
Supervisor : Dr. Feeley

A Context for Computers in Education
Huggett, Michael
Master’s essay available in print and online : https://bibrrs.library.ubc.ca/vwebv/holdingsInfo?bibId=121639
Degree : Master of Science - MSc
Graduation Date : 2001-05
Supervisors : Dr. Conati, Dr. Rosenberg

Free speech on the global internet:  the role of e-commerce
Khangura, Harinder Singh
URI : http://hdl.handle.net/2429/11773
Degree : Master of Science - MSc
Graduation Date : 2001-11
Supervisor : Dr. Rosenberg

Deformable model acquisition and validation
Lang, Jochen
URI : http://hdl.handle.net/2429/13753
Degree : Doctor of Philosophy - PhD
Graduation Date : 2001-11
Supervisor : Dr. Woodham

Objects deform in response to contact forces exerted on them. The deformation depends on material properties, the geometry of the object and external forces. This thesis develops a robotic system for automatically acquiring observations of a deforming object and for estimating a model of the deformation from these observations. Models of deformable objects are in wide-spread use in simulation, computer graphics and virtual reality. Deformation, impact and fitting simulation aid manufacturing. In computer graphics deformable objects are designed and animated. Medical simulators incorporating physical models of organs and tissue are a significant emerging virtual reality application. The material properties of deformable models are often assigned based on mechanical (and other) testing of material samples. Material samples do not represent commonly simulated objects well if there is a high variability in the material of the object, e.g., due to mixed material, unknown material, or material with imperfections. In contrast to material sampling, this thesis develops a method to scan the deformation behavior of a complete object. The scanning is analogous to the scanning of the visual appearance of an object. The scan captures the individual response of a complete object to contact forces. The result of the scan is not only a deformable model but also data which serves to validate the model. This validation step gives a qualitative and sometimes quantitative assessment of the suitability of a model.

Interaction-based Simulation
Lee, Gene
URI : http://hdl.handle.net/2429/13574
Degree : Doctor of Philosophy - PhD
Graduation Date : 2001-11
Supervisor : Dr. Murphy

This thesis presents a technique for producing visual simulations — programs that visualize the execution or behavior of time-varying scenes — from software interactions, first-class structures that moderate the flow of information among software components: The building of programs with software interactions gives rise to Interaction-Based Programming (IBP), a programming methodology that separates the concerns of computation from coordination. Software components compute independently, while software interactions coordinate communications. The integration of IBP with the methods of computer simulation produce Interaction-Based Simulation (IBS), an approach to visual simulation that binds the execution of software interactions to the advancement of time. As tiihe advances, software interactions control the flow of information among components arid the dissemination of temporal information. The utility of IBS is presented in two ways: one, through a logical description of the effect of software interactions on software development and systems created using the approach; and two, through empirical evidence demonstrating the ability of IBS to produce a wide variety of programs that encourage the reuse of software.

Supporting user mobility with Web-based mobile computing
Li, Naizhi (Steven)
URI : http://hdl.handle.net/2429/11712
Degree : Master of Science - MSc
Graduation Date : 2001-05
Supervisor : Dr. Vuong

Keeping TCP connections intact across server failures
Li, Rui
URI : http://hdl.handle.net/2429/11373
Degree : Master of Science - MSc
Graduation Date : 2001-05
Supervisor : Dr. Hutchinson

An automatic layout generator for integrated circuit design
Lin, Lan
URI : http://hdl.handle.net/2429/11828
Degree : Master of Science - MSc
Graduation Date : 2001-11
Supervisor : Dr. Greenstreet

Intersecting red and blue line segments in optimal time and precision
Mantler, Andrea Louise
URI : http://hdl.handle.net/2429/11868
Degree : Master of Science - MSc
Graduation Date : 2001-11
Supervisors : Dr. Snoeyink, Dr. Kirkpatrick

Approximate value-directed belief state monitoring for partially obserable Markov decision processes
Poupart, Pascal
URI : http://hdl.handle.net/2429/11462
Degree : Master of Science - MSc
Graduation Date : 2001-05
Supervisor : Dr. Boutilier

Migration of WAFL to GSD
Reddy, Sreelatha Sunkara
URI : http://hdl.handle.net/2429/11429
Degree : Master of Science - MSc
Graduation Date : 2001-05
Supervisor : Dr. Hutchinson

Symmetric Collaborative filtering using the noisy sensor model
Sharma, Rita
URI : http://hdl.handle.net/2429/11450
Degree : Master of Science - MSc
Graduation Date : 2001-05
Supervisor : Dr. Poole

Kinetic Data Structures for Collision Detection
Speckmann, Bettina
PhD thesis available in print and online : https://bibrrs.library.ubc.ca/vwebv/holdingsInfo?bibId=129831
Degree : Master of Science - MSc
Graduation Date : 2001-11
Supervisors : Dr. Snoeyink, Dr. Kirkpatrick

Digital Watermarking by DCT coefficient manipulation
Sun, Xiaodi
URI : http://hdl.handle.net/2429/11880
Degree : Master of Science - MSc
Graduation Date : 2001-11
Supervisor : Dr. Vuong

Multiple light source optical flow for translations and rotations in the image plane
Takagi, Shingo Jason
URI : http://hdl.handle.net/2429/11457
Degree : Master of Science - MSc
Graduation Date : 2001-05
Supervisor : Dr. Woodham

Flows: a novel infrastructure for communication in distributed systems
Warfield, Andrew Kent
URI : http://hdl.handle.net/2429/11726
Degree : Master of Science - MSc
Graduation Date : 2001-05
Supervisor : Dr. Hutchinson

Temporal properties of self-timed rings
Winstanley, Anthony James
URI : http://hdl.handle.net/2429/11912
Degree : Master of Science - MSc
Graduation Date : 2001-11
Supervisor : Dr. Greenstreet

Iceberg-cube computation with PC cluster
Yin, Yu  (Ivy)
URI : http://hdl.handle.net/2429/11930
Degree : Master of Science - MSc
Graduation Date : 2001-11
Supervisor : Dr. Wagner

KELP:  An architecture for understanding global system behavior in massively scalable distributed systems
Yung, Arthur
URI : http://hdl.handle.net/2429/11613
Degree : Master of Science - MSc
Graduation Date : 2001-05
Supervisor : Dr. Feeley