Marie-Laure Mugnier - Böcker

The knowledge representation and reasoning formalism presented here is a graph formalism – knowledge is represented by labeled graphs, in the graph theory sense, and r- soning mechanisms are based on graph operations, with graph homomorphism at the core.

This book provides a de?nition and study of a knowledge representation and r- soning formalism stemming from conceptual graphs, while focusing on the com- tational properties of this formalism. Knowledge can be symbolically represented in many ways. The knowledge representation and reasoning formalism presented here is a graph formalism – knowledge is represented by labeled graphs, in the graph theory sense, and r- soning mechanisms are based on graph operations, with graph homomorphism at the core. This formalism can thus be considered as related to semantic networks. Since their conception, semantic networks have faded out several times, but have always returned to the limelight. They faded mainly due to a lack of formal semantics and the limited reasoning tools proposed. They have, however, always rebounded - cause labeled graphs, schemas and drawings provide an intuitive and easily und- standable support to represent knowledge. This formalism has the visual qualities of any graphic model, and it is logically founded. This is a key feature because logics has been the foundation for knowledge representation and reasoning for millennia. The authors also focus substantially on computational facets of the presented formalism as they are interested in knowledge representation and reasoning formalisms upon which knowledge-based systems can be built to solve real problems. Since object structures are graphs, naturally graph homomorphism is the key underlying notion and, from a computational viewpoint, this moors calculus to combinatorics and to computer science domains in which the algorithmicqualitiesofgraphshavelongbeenstudied,asindatabasesandconstraint networks.

This book constitutes the refereed proceedings of the 8th International Conference on Web Reasoning and Rule Systems, RR 2014, held in Athens, Greece in September 2014. The 9 full papers, 9 technical communications and 5 poster presentations presented together with 3 invited talks, 3 doctoral consortial papers were carefully reviewed and selected from 33 submissions. The conference covers a wide range of the following: semantic Web, rule and ontology languages, and related logics, reasoning, querying, searching and optimization, incompleteness, inconsistency and uncertainty, non-monotonic, common sense, and closed-world reasoning for the web, dynamic information, stream reasoning and complex event processing, decision making, planning, and intelligent agents, machine learning, knowledge extraction and information retrieval, data management, data integration and reasoning on the web of data, ontology-based data access, system descriptions, applications and experiences.

The 13th International Conference on Conceptual Structures (ICCS 2005) was held in Kassel, Germany, during July 17-22, 2005. Information about the c- ference can be found athttp://www.kde.cs.uni-kassel.de/conf/iccs05. The title of this year's conference, "Common Semantics for Sharing Kno- edge",waschosentoemphasizeontheonehandtheoverallaimofanyknowledge representationformalism, to support the sharing of knowledge, and on the other hand the importance of a common semantics to avoiddistortion of the meaning. We understand that both aspects are of equal importance for a successful future of the researcharea of conceptual structures. We are thus happy that the papers presentedatICCS2005addressedbothapplicationsandtheoreticalfoundations. "Sharing knowledge" can also be understood in a separate sense. Thanks to the German Research Foundation, DFG, we were able to invite nine inter- tionally renowned researchers from adjacent research areas. We had stimulating presentationsandlively discussions,with bidirectionalknowledgesharing.Ev- tually the ground can be laid for establishing common semantics between the respective theories.This year, 66 papers were submitted, from which 22 were selected to be included in this volume. In addition, the ?rst nine papers present the invited talks.Wewishtoexpressourappreciationtoalltheauthorsofsubmittedpapers, to the members of the Editorial Board and the Program Committee, and to the external reviewers for making ICCS 2005 a valuable contribution to the knowledge processing research ?eld.