TY - JOUR T1 - Type-Elimination-Based Reasoning for the Description Logic SHIQbs using Decision Diagrams and Disjunctive Datalog JF - Logical Methods in Computer Science Y1 - 2012 A1 - Sebastian Rudolph A1 - Markus Krötzsch A1 - Pascal Hitzler KW - datalog KW - decision diagrams KW - description logics KW - type elimination AB - We propose a novel, type-elimination-based method for standard reasoning in the description logic SHIQbs extended by DL-safe rules. To this end, we first establish a knowledge compilation method converting the terminological part of an ALCIb knowledge base into an ordered binary decision diagram (OBDD) that represents a canonical model. This OBDD can in turn be transformed into disjunctive Datalog and merged with the assertional part of the knowledge base in order to perform combined reasoning. In order to leverage our technique for full SHIQbs, we provide a stepwise reduction from SHIQbs to ALCIb that preserves satisfiability and entailment of positive and negative ground facts. The proposed technique is shown to be worst-case optimal w.r.t. combined and data complexity. VL - 8 UR - http://dx.doi.org/10.2168/LMCS-8(1:12)2012 ER - TY - CONF T1 - A Better Uncle for OWL: Nominal Schemas for Integrating Rules and Ontologies T2 - Proceedings of the 20th International Conference on World Wide Web, WWW 2011, Hyderabad, India, March 28 - April 1, 2011 Y1 - 2011 A1 - Markus Krötzsch A1 - Frederick Maier A1 - Adila Krisnadhi A1 - Pascal Hitzler ED - Sadagopan Srinivasan ED - Krithi Ramamritham ED - Arun Kumar ED - M. P. Ravindra ED - Elisa Bertino ED - Ravi Kumar KW - datalog KW - Description Logic KW - Semantic Web Rule Language KW - SROIQ KW - tractability KW - Web Ontology Language AB - We propose a description-logic style extension of OWL 2 with nominal schemas which can be used like "variable nominal classes" within axioms. This feature allows ontology languages to express arbitrary DL-safe rules (as expressible in SWRL or RIF) in their native syntax. We show that adding nominal schemas to OWL 2 does not increase the worst-case reasoning complexity, and we identify a novel tractable language SROELV3(\cap, x) that is versatile enough to capture the lightweight languages OWL EL and OWL RL. JF - Proceedings of the 20th International Conference on World Wide Web, WWW 2011, Hyderabad, India, March 28 - April 1, 2011 PB - ACM SN - 978-1-4503-0632-4 UR - http://doi.acm.org/10.1145/1963405.1963496 ER -