Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Keyword
- Publication
- Publication Type
Articles 1 - 7 of 7
Full-Text Articles in Physical Sciences and Mathematics
Generating Linear Orders Of Events For Geospatial Domains, Suzannah Hall
Generating Linear Orders Of Events For Geospatial Domains, Suzannah Hall
Electronic Theses and Dissertations
Events in the world do not occur in neat chronological order, but may take place, for example, during or overlapping each other, or as simultaneous events. Efficient summaries of real-world events are important in many disciplines and require events to be modeled in a linear fashion. This thesis focuses on modeling events as intervals and using relations between the events to derive linear orders from more complex partially ordered sets. A method is developed for mapping Allen's thirteen temporal relations to only two relations, before and equals, which allow a linear ordering of all events present in the set. This …
Using Linear Features For Aerial Image Sequence Mosaiking, Caixia Wang
Using Linear Features For Aerial Image Sequence Mosaiking, Caixia Wang
Electronic Theses and Dissertations
With recent advances in sensor technology and digital image processing techniques, automatic image mosaicking has received increased attention in a variety of geospatial applications, ranging from panorama generation and video surveillance to image based rendering. The geometric transformation used to link images in a mosaic is the subject of image orientation, a fundamental photogrammetric task that represents a major research area in digital image analysis. It involves the determination of the parameters that express the location and pose of a camera at the time it captured an image. In aerial applications the typical parameters comprise two translations (along the x …
Context-Specific Preference Learning Of One Dimensional Quantitative Geospatial Attributes Using A Neuro-Fuzzy Approach, Georgios Mountrakis
Context-Specific Preference Learning Of One Dimensional Quantitative Geospatial Attributes Using A Neuro-Fuzzy Approach, Georgios Mountrakis
Electronic Theses and Dissertations
Change detection is a topic of great importance for modern geospatial information systems. Digital aerial imagery provides an excellent medium to capture geospatial information. Rapidly evolving environments, and the availability of increasing amounts of diverse, multiresolutional imagery bring forward the need for frequent updates of these datasets. Analysis and query of spatial data using potentially outdated data may yield results that are sometimes invalid. Due to measurement errors (systematic, random) and incomplete knowledge of information (uncertainty) it is ambiguous if a change in a spatial dataset has really occurred. Therefore we need to develop reliable, fast, and automated procedures that …
A Data Model For Exploration Of Temporal Virtual Reality Geographic Information Systems, Jorge Alberto Prado De Campos
A Data Model For Exploration Of Temporal Virtual Reality Geographic Information Systems, Jorge Alberto Prado De Campos
Electronic Theses and Dissertations
Geographic information systems deal with the exploration, analysis, and presentation of geo-referenced data. Virtual reality is a type of human-computer interface that comes close to the way people perceive information in the real world. Thus, virtual reality environments become the natural paradigm for extending and enhancing the presentational and exploratory capability of GIs applications in both the spatial and temporal domains. The main motivation of this thesis is the lack of a framework that properly supports the exploration of geographic information in a multi-dimensional and multi-sensorial environment (i.e., temporal virtual reality geographic information systems). This thesis introduces a model for …
Structuring A Wayfinder's Dynamic And Uncertain Environment, Michael D. Hendricks
Structuring A Wayfinder's Dynamic And Uncertain Environment, Michael D. Hendricks
Electronic Theses and Dissertations
Wayfinders typically travel in dynamic environments where barriers and requirements change over time. In many cases, uncertainty exists about the future state of this changing environment. Current geographic information systems lack tools to assist wayfinders in understanding the travel possibilities and path selection options in these dynamic and uncertain settings. The goal of this research is a better understanding of the impact of dynamic and uncertain environments on wayfinding travel possibilities. An integrated spatio-temporal framework, populated with barriers and requirements, models wayfinding scenarios by generating four travel possibility partitions based on the wayfinder's maximum travel speed. Using these partitions, wayfinders …
U.S. Graduate Student Travel To The Second Agentlink European Agent Systems Summer School (Easss) 2000, Thomas A. Wagner
U.S. Graduate Student Travel To The Second Agentlink European Agent Systems Summer School (Easss) 2000, Thomas A. Wagner
University of Maine Office of Research Administration: Grant Reports
This award supports international travel for fifteen U.S. graduate students who would not otherwise be able to attend the Second AgentLink European Agent Systems Summer School being held in Saarbrucken, Germany, from August 14-18, 2000. AgentLink, Europe's ESPRIT-funded Network of Excellence for agent-based computing, organizes the school (http://www.agentlink.org). It is a world-class event that will bring together internationally recognized researchers in the area of autonomous agents and multi-agent systems to present introductory and advanced courses in the theoretical and practical aspects of agent-based computing. The objective of this award is to encourage and enable U.S. graduate students of outstanding merit …
The Effects Of Microprocessor Architecture On Speedup In Distrbuted Memory Supercomputers, Glen L. Beane
The Effects Of Microprocessor Architecture On Speedup In Distrbuted Memory Supercomputers, Glen L. Beane
Electronic Theses and Dissertations
Amdahl's Law states that speedup in moving from one processor to N identical processors can never be greater than N, and in fact usually is lower than N because of operations that must be done sequentially. Amdahl's Law gives us the following formula for speedup: Speedup < or = (S+P)/(S+(P/N)) where is the number of processors, S is the percentage of the code that is serial (i.e., cannot be parallelized), and P is the percentage of code that is parallelizable. We can substitute 1 - S for P in the above formula and we see that as S approaches zero speedup approaches N. It can also be shown that seemingly small values of S can severely limit the maximum speedup. Researchers at the University of Maine saw speedups that seemed to contradict Amdahl's Law, and identified an assumption made by the law that is not always true. When this assumption is not true, it is possible to achieve speedups that are larger than the theoretical maximum speedup of N given by Amdahl's Law. The assumption in question is that the computer performance scales linearly as the size of the problem is reduced by dividing it over a larger number of processors. This assumption is not valid for computers with tiered memory. In this thesis we investigate superlinear speedup through a series of test programs specifically designed to exhibit superlinear speedup. After demonstrating these programs show superlinear speedup, we suggest methods for detecting the potential for superlinear speedup in a variety of algorithms.