foundations of computational agents
Sowa  and Brachman and Levesque  give an overview of knowledge representation. Davis  is an accessible introduction to a wealth of knowledge representation issues in commonsense reasoning. Brachman and Levesque  present many classic knowledge representation papers. See Woods  for an overview of semantic networks.
For an overview of the philosophical and computational aspects of ontologies, see Smith  and Sowa . For an overview of the semantic web see Antoniou and van Harmelen , Berners-Lee et al. , and Hendler et al. . Janowicz et al.  explain the role of semantics in big data. The ontology summit (http://ontologforum.org/index.php/OntologySummit) produces an annual communique that provides a good summary of many issues in using ontologies.
DBpedia [Auer et al., 2007], and YAGO [Suchanek et al., 2007; Hoffart et al., 2013; Mahdisoltani et al., 2015], Wikidata [Vrandečić and Krötzsch, 2014], (http://www.wikidata.org/) and Knowledge Vault [Gabrilovich et al., 2014] are large knowledge bases that use triples and ontologies to represent facts about millions of entities.
The top-level ontology is based on BFO, the Basic Formal Ontology, described in Grenon and Smith , Smith , Arp et al.  and the ontology of Sowa . Other top-level ontologies include DOLCE [Gangemi et al., 2003], Cyc [Panton et al., 2006] and SUMO [Niles and Pease, 2001; Pease, 2011]. A more lightweight and widely used ontology is at http://schema.org.