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Document Type

Open Access Dissertation

Degree Name

Doctor of Philosophy (PhD)

Degree Program

Computer Science

Year Degree Awarded

Winter 2015

First Advisor

Andrew McCallum

Subject Categories

Artificial Intelligence and Robotics | Databases and Information Systems | Numerical Analysis and Scientific Computing | Other Computer Sciences

Abstract

Knowledge bases (KB) facilitate real world decision making by providing access to structured relational information that enables pattern discovery and semantic queries. Although there is a large amount of data available for populating a KB; the data must first be gathered and assembled. Traditionally, this integration is performed automatically by storing the output of an information extraction pipeline directly into a database as if this prediction were the ``truth.'' However, the resulting KB is often not reliable because (a) errors accumulate in the integration pipeline, and (b) they persist in the KB even after new information arrives that could rectify these errors. We envision a paradigm-shift in KB construction for addressing these concerns that we term an ``epistemological'' database. In epistemological databases the existence and properties of entities are not directly input into the DB; they are instead determined by inference on raw evidence input into the DB. This shift in thinking is important because it allows inference to revisit previous conclusions and retroactively correct errors as new evidence arrives. Evidence is abundant and in steady supply from web spiders, semantic web ontologies, external databases, and even groups of enthusiastic human editors. As this evidence continues to accumulate and inference continues to run in the background, the quality of the knowledge base continues to improve. In this dissertation we develop the machine learning components necessary to achieve epistemological knowledge base construction at scale with key contributions in modeling, inference and learning.

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