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Semantic similarity measures play an important role in information retrieval and information integration. Traditional approaches to modeling semantic similarity compute the semantic distance between definitions within a single ontology. This single ontology is either a domain-independent ontology or the result of the integration of existing ontologies. We(More)
Semantic similarity plays an important role in geographic information systems as it supports the identification of objects that are conceptually close, but not identical. Similarity assessments are particularly important for retrieval of geospatial data in such settings as digital libraries, heterogeneous databases, and the World Wide Web. Although some(More)
This article compares several page ordering strategies for Web crawling under several metrics. The objective of these strategies is to download the most "important" pages "early" during the crawl. As the coverage of modern search engines is small compared to the size of the Web, and it is impossible to index all of the Web for both theoretical and practical(More)
This paper describes a new spatio-temporal access method (SEST-Index) that combines two approaches for modeling spatio-temporal information: snapshots and events. This method makes it possible to not only process <i>time slice</i> and <i>interval</i> queries, but also queries about events. The SEST Index implementation uses an R-tree structure for storing(More)
The assessment of semantic similarity among objects is a basic requirement for semantic interoperability. This paper presents an innovative approach to semantic similarity assessment by combining the advantages of two different strategies: feature-matching process and semantic distance calculation. The model involves a knowledge base of spatial concepts(More)
This paper derives and compares two strategies for minimizing topological constraints in a query expressed by a visual example: (1) elimination of topological relations that are implied uniquely by composition and (2) restriction to topological relations that relate near-neighbor objects, as determined by a Delaunay triangulation. In both cases, the query(More)
— This paper presents a comparative study of strategies for crawling the Web. In particular we show that a combination of breadth-first ordering with the largest sites first is a practical alternative since it is simple to implement, it is fast and is able to retrieve the best ranked pages at a rate that is closer to the optimal than the other alternatives.(More)
Algebras over spatial relations have become an important aspect of spatial reasoning for retrieving and handling large and complex spatial data sets. While such spatial relations play a fundamental role in specifying constraints in a spatial query language, there has been little concern as to whether existing spatial-relation algebras are cognitively(More)