Geospatial database generation from digital newspapers: use case for risk and disaster domains.

Dissertation submitted in partial fulfilment of the requirements for the Degree of Master of Science in Geospatial Technologies.The generation of geospatial databases is expensive in terms of time and money. Many geospatial users still lack spatial data. Geographic Information Extraction and Retrieval systems can alleviate this problem. This work proposes a method to populate spatial databases automatically from the Web. It applies the approach to the risk and disaster domain taking digital newspapers as a data source. News stories on digital newspapers contain rich thematic information that can be attached to places. The use case of automating spatial database generation is applied to Mexico using placenames. In Mexico, small and medium disasters occur most years. The facts about these are frequently mentioned in newspapers but rarely stored as records in national databases. Therefore, it is difficult to estimate human and material losses of those events. This work present two ways to extract information from digital news using natural languages techniques for distilling the text, and the national gazetteer codes to achieve placename-attribute disambiguation. Two outputs are presented; a general one that exposes highly relevant news, and another that attaches attributes of interest to placenames. The later achieved a 75% rate of thematic relevance under qualitative analysis

Parsing for agile modeling

Agile modeling refers to a set of methods that allow for a quick initial development of an importer and its further refinement. These requirements are not met simultaneously by the current parsing technology. Problems with parsing became a bottleneck in our research of agile modeling. In this thesis we introduce a novel approach to specify and build parsers. Our approach allows for expressive, tolerant and composable parsers without sacrificing performance. The approach is based on a context-sensitive extension of parsing expression grammars that allows a grammar engineer to specify complex language restrictions. To insure high parsing performance we automatically analyze a grammar definition and choose different parsing strategies for different parts of the grammar. We show that context-sensitive parsing expression grammars allow for highly composable, tolerant and variable-grained parsers that can be easily refined. Different parsing strategies significantly insure high-performance of parsers without sacrificing expressiveness of the underlying grammars

Parallel Natural Language Parsing: From Analysis to Speedup

Electrical Engineering, Mathematics and Computer Scienc

A Formal Approach to Computer Aided 2D Graphical Design for Blind People

The growth of computer aided drawing systems for blind people (CADB) has long been recognised and has increased in interest within the assistive technology research area. The representation of pictorial data by blind and visually impaired (BVI) people has recently gathered momentum with research and development; however, a survey of published literature on CADB reveals that only marginal research has been focused on the use of a formal approach for on screen spatial orientation, creation and reuse of graphics artefacts. To realise the full potential of CADB, such systems should possess attributes of usability, spatial navigation and shape creation features without which blind users drawing activities are less likely to be achieved. As a result of this, usable, effective and self-reliant CADB have arisen from new assistive Technology (AT) research. This thesis contributes a novel, abstract, formal approach that facilitates BVI users to navigate on the screen, create computer graphics/diagrams using 2D shapes and user-defined images. Moreover, the research addresses the specific issues involved with user language by formulating specific rules that make BVI user interaction with the drawing effective and easier. The formal approach proposed here is descriptive and it is specified at a level of abstraction above the concrete level of system technologies. The proposed approach is unique in problem modelling and syntheses of an abstract computer-based graphics/drawings using a formal set of user interaction commands. This technology has been applied to enable blind users to independently construct drawings to satisfy their specific needs without recourse to a specific technology and without the intervention of support workers. The specification aims to be the foundation for a system scope, investigation guidelines and user-initiated command-driven interaction. Such an approach will allow system designers and developers to proceed with greater conceptual clarity than it is possible with current technologies that is built on concrete system-driven prototypes. In addition to the scope of the research the proposed model has been verified by various types of blind users who have independently constructed drawings to satisfy their specific needs without the intervention of support workers. The effectiveness and usability of the proposed approach has been compared against conventional non-command driven drawing systems by different types of blind users. The results confirm that the abstract formal approach proposed here using command-driven means in the context of CADB enables greater comprehension by BVI users. The innovation can be used for both educational and training purposes. The research, thereby sustaining the claim that the abstract formal approach taken allows for the greater comprehension of the command-driven means in the context of CADB, and how the specification aid the design of such a system