In the context of a project to populate knowledge-bases from large-scale unstructured information, we have encountered numerous problems integrating the extracted information and the knowledge-base, due to mismatches in semantics between the two. Semantic integration in general is quite hard, however we have found that many of the integration problems stem from unclear or ambiguous semantics on the extraction side. We have begun to catalog and document these ambiguities and report here on one in particular: the use and intended meaning of multiple annotations on a span of text. Multiple annotations are a representation structure used in at least seven semantically distinct ways by existing information extraction systems. This overloading makes the representation ambiguous, and creates an obstacle for integration. We focus on these different semantic interpretations and propose a more expressive representation that allows their differences to be expressed.
By: Christopher A. Welty, J. William Murdock
Published in: RC22979 in 2003
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