Engineering Commons^™

Gridfields: Model-Driven Data Transformation In The Physical Sciences, Bill Howe

Dissertations and Theses

Scientists' ability to generate and store simulation results is outpacing their ability to analyze them via ad hoc programs. We observe that these programs exhibit an algebraic structure that can be used to facilitate reasoning and improve performance. In this dissertation, we present a formal data model that exposes this algebraic structure, then implement the model, evaluate it, and use it to express, optimize, and reason about data transformations in a variety of scientific domains.

Simulation results are defined over a logical grid structure that allows a continuous domain to be represented discretely in the computer. Existing approaches for manipulating …

Efficient Support For Application-Specific Video Adaptation, Jie Huang

Dissertations and Theses

As video applications become more diverse, video must be adapted in different ways to meet the requirements of different applications when there are insufficient resources. In this dissertation, we address two sorts of requirements that cannot be addressed by existing video adaptation technologies: (i) accommodating large variations in resolution and (ii) collecting video effectively in a multi-hop sensor network. In addition, we also address requirements for implementing video adaptation in a sensor network.

Accommodating large variation in resolution is required by the existence of display devices with widely disparate screen sizes. Existing resolution adaptation technologies usually aim at adapting video …

Addressing Cheating And Workload Characterization In Online Games, Christopher Chambers

Dissertations and Theses

The Internet has enabled the popular pastime of playing video games to grow rapidly by connecting game players in disparate locations. However, with popularity have come the two challenges of hosting a large number of users and detecting cheating among users. For reasons of control, security, and ease of development, the most popular system for hosting on-line games is the client server architecture. This is also the most expensive and least scalable architecture for the game publisher, which drives hosting costs upwards with the success of the game. In addition to the expense of hosting, as a particular game grows …