http://hdl.handle.net/1957/10238 2013-05-22T20:29:59Z http://hdl.handle.net/1957/35859 Finding and using chokepoints in Stratagus Brewster, Benjamin This paper describes a method for finding areas of interest on a two-dimensional grid map used in the real-time strategy engine Stratagus. The method involves discovering chokepoints where through all simulation agents must pass. Using a set of tunable parameters, a full set of chokepoints are located. The redundant and useless chokepoints are then filtered out of the set. The resulting chokepoints can then be used to create a graph of the high-level map structure. The method used to cull less-useful chokepoints is presented. Secondarily, two algorithms were developed that help decide at which chokepoints a limited number of defensive structures may be placed for the greatest benefit. The results of a series of tests are given that show that these algorithms are valuable: tower placements based on both the optimal and greedy implementations, built on the maximum flow of the resultant graph, perform markedly better than random placement. Further, the framework (also by the author) used in this project is dissected. Graduation date: 2008 2007-01-01T00:00:00Z http://hdl.handle.net/1957/35665 Using web services for image processing in a desktop widgets engine Le, Hien Desktop widget engines have emerged as an alternative for completing simple tasks without the need for a full-blown application or constant user interaction. Widgets can simply display data in a compact and visually appealing manner (such as stock tickers, weather forecasts, and news notifications), or go so far as to provide alternative interfaces to sites that expose their services via an API. This project aims to develop an image processing application where the key features are provided neither locally nor by a single host. The Yahoo! Widgets Engine is used to design a simple image processing interface where processing operations are mapped to widgets that can be connected together to create more complex operations. Actual data processing occurs remotely via calls to a REST-style Java web service to allow for a non-local and decentralized system. Graduation date: 2008 2007-06-14T00:00:00Z http://hdl.handle.net/1957/34563 Derivative-Based Relief Mapping Tichenor, Michael This project presents a new, and more versatile, method for performing Relief Mapping (also known as Parallax Occlusion Mapping), utilizing rates of change in texture coordinates across a polygon surface to calculate the texture sampling offsets used in the ray-tracing portion of the Relief Mapping algorithm. This new technique relies solely upon the texture-coordinates, vertex-coordinates, and a depth-map texture, allowing Relief Mapping to be utilized on complex meshes without the need for additional per-polygon information such as texture-aligned tangents or normal maps. Graduation date: 2013 2012-10-29T00:00:00Z http://hdl.handle.net/1957/34552 Applications of Conditional Topic Models to Species Distribution Prediction Wilkins, Paul Christopher The topic of species distribution modelling has been on of increasing interest in recent years. As climate change is becoming of even more interest to researchers, more tools are needed to better analyze and predict various climate change scenarios. One particular area of interest is that of species distribution modeling. Species distribution modelling addresses the problem of determining either the fundamental or the realized niche of a species, either at the current time or projecting into the past or future. Species distribution models (SDMs) are seen as a potentially powerful tool both for applied policy decisions like reservation design and theorectical understanding, discovering what factors are most important in determining the fundamental niche of a species, as well as the extent to which various factors determine how much of that niche is realized. Currently, almost all SDMs focus on a single species at a time. For any given species, a model is developed and trained for that particular species. An advantage of this approach is that is keep computational costs down relative to a broader model. There is, however, potential in the idea that by modeling multiple species at once, mutual information between species can be leveraged to provide more accurate modeling while offering insights into the nature of the relationships between specific species. This paper examines the attempt to use one such model for doing species distribution modeling on several species at once. 2010-07-20T00:00:00Z