Download PDFOpen PDF in browserSecrecy-Preserving Reasoning and Query Answering in Probabilistic Description Logic Knowledge Bases14 pages•Published: October 19, 2017AbstractIn this paper we study Secrecy-Preserving Query Answering problem underthe OpenWorld Assumption (OWA) for Prob-EL>0;=1 Knowledge Bases (KBs). We have designed a tableau procedure to compute a semi model M over the given KB which eventually is equivalent to a probabilistic model to KB. Given a secrecy set S, which is a finite set of assertions, we compute a function E, called an envelope of S, which assigns a set E() of assertions to each world in the semi modal M. E provides logical protection to the secrecy set S against the reasoning of a querying agent. Once the semi model M and an envelope E are computed, we define the secrecy-preserving semi model ME. Based on the information available in ME, assertional queries with probabilistic operators can be answered eciently while preserving secrecy. To the best of our knowledge, this work is first one studying secrecy-preserving reasoning in description logic augmented with probabilistic operators. When the querying agent asks a query q, the reasoner answers “Yes” if information about q is available in ME; otherwise, the reasoner answers “Unknown”. Being able to answer “Unknown” plays a key role in protecting secrecy under OWA. Since we are not computing all the consequences of the knowledge base, answers to the queries based on just secrecy-preserving semi model ME could be erroneous. To fix this problem, we further augment our algorithms by providing recursive query decomposition algorithm to make the query answering procedure foolproof. 1 Keyphrases: knowledge bases, probabilistic description logic, query answering, secrecy preserving reasoning In: Christoph Benzmüller, Christine Lisetti and Martin Theobald (editors). GCAI 2017. 3rd Global Conference on Artificial Intelligence, vol 50, pages 188-201.
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