The paper extends the recently published methods for image reconstruction and texture minification using the generalized ripmap method, named fipmap, and quad-trees. Fipmap is based on the technique of partitioned iterated function systems, used in fractal image compression. The quad-tree texture reconstruction algorithm works well for many standard cases. The special cases can be solved using ...

The working papers published in the Series constitute work in progress circulated to stimulate discussion and critical comments. Views expressed represent exclusively the authors' own opinions and do not necessarily reflect those of the editors. Die Deutsche Nationalbibliothek verzeichnet diese Publikation in der Deutschen Nationalbibliografie; detaillierte bibliografische Daten sind im Interne...

Elliptic and hyperbolic partial differential equation methods for generating both surface and volume structured grids have been implemented in the Gridgen software system. Their implementation provides the means by which very high quality quad and hex grids can be generated for computational fluid dynamics (CFD). The grids, in turn, provide the basis for highly accurate CFD simulations of visco...

An adaptive mesh projection method for the time-dependent incompressible Euler equations is presented. The domain is spatially discretised using quad/octrees and a multilevel Poisson solver is used to obtain the pressure. Complex solid boundaries are represented using a volume-of-fluid approach. Second-order convergence in space and time is demonstrated on regular, statically and dynamically re...

Conservative dynamical systems propagate as stationary points of the action functional. Using this representation, it has previously been demonstrated that one may obtain fundamental solutions for two-point boundary value problems for some classes of conservative systems via solution of an associated dynamic program. Further, such a fundamental solution may be represented as a set of solutions ...

INTRODUCTION My research career began as an undergraduate in Software Engineering, exploring formal specification of functional models. My interest in the human aspects of software engineering led me to Human-Computer Interaction (HCI) and Ubiquitous Computing as a graduate student, where I have investigated automated meeting capture and access. I implemented and evaluated prototypes that captu...

In this paper we present a Model Predictive Path Integral (MPPI) control algorithm that is derived from the path integral control framework and a generalized importance sampling scheme. In order to operate in real time we parallelize the sampling based component of the algorithm and achieve massive speed-up by using a Graphical Processor Unit (GPU). We compare MPPI against traditional model pre...

A high-conversion-rate high-resolution oversampling digital-to-analog converter (DAC) for direct digital modulation is addressed in this paper. A new type of switching scheme, called differential-quad switching, is presented. To verify the feasibility of this scheme, essential parts with some auxiliary circuitry for interfacing were fabricated in a 0.8m CMOS technology. Measured results show th...