Since the I/O subsystem is the bottleneck in external mergesort, I/O parallelism can result in substantial performance improvements. Concurrency can be introduced by overlapping I/O requests at different disks, and the average service time can be reduced by reading several blocks on each I/O operation. However, a RAM-based cache is required to support ...

A significant challenge of autonomous robotics in transportation, exploration, and search-and-rescue missions lies in the area of motion planning. The overall objective is to enable robots to automatically plan the low-level motions needed to accomplish assigned high-level tasks. Toward this goal, this thesis proposes a novel multi-layered approach, ...

In four experiments, the utility of a spreadsheet debugging tool was assessed as spreadsheet users interacted with experimental spreadsheets. Experiments 1 and 2 showed that although subjective reactions to the tools were favorable, the performance advantage offered by them was not statistically significant. Experiment 3 assessed the applicability ...

Volume visualization of large volume data sets is traditionally based on surface fitting algorithms. With recent advances in graphics computation and memory capabilities, direct volume rendering techniques to produce interactive volume rendering for large data sets have become feasible. We implement a custom texture based volume rendering algorithm ...

This thesis describes a method to simulate parallel programs written for shared memory multiprocessors. We have extended execution-driven simulation to facilitate the simulation of shared memory. We have developed a shared memory profiler, which, at compile-time, inserts simulation support code into the assembly code of the program to be able to ...

Conflict-aware replication is a novel lazy replication technique for scaling the back-end database of a dynamic content web server using a cluster of commodity computers. This technique provides both throughput scaling and 1-copy serializability. It has generally been believed that this combination is hard to achieve through replication because of ...

The determination of first-arrival seismic traveltimes radiating outward from a point-source in an arbitrary slowness field plays an important role in methods which require knowledge of curved wavefronts in a complex domain. Adaptations of the 1st order upwind finite difference Godunov and 2nd MUSCL schemes are presented which model the two dimensional ...

Internet video streaming places new demands on source coding and network transport algorithms. The challenge is to deliver compressed video packets before their play-out deadline, despite of varying throughput, packet delay, and loss. This problem has to be solved in a way that simultaneously maximizes the video quality at the streaming client, meets ...

Optimal Control of systems governed by Partial Differential Equations is an applications-driven area of mathematics involving the formulation and solution of minimization problems. Given a physical phenomenon described by a differential equation, the Optimal Control Problem (OCP) seeks to force state variables to behave in a particular, desired way. ...

Neurocognitive Linguistic Theory (NCL, Lamb 1999) stands alone as the only well-developed linguistic theory with a serious commitment to neurological plausibility. It is also set apart from much of mainstream Cognitive Science by its strictly non-symbolic approach to understanding cognition. The theory has enjoyed a long a fruitful development, but ...