Selected papers from EKAW 2018

This special issue gathers the extended version of three of the four best papers accepted at EKAW 2018, the 21st International Conference on Knowledge Engineering and Knowledge Management, held in Nancy, France, in November 2018. The special theme of EKAW 2018 was Knowledge and AI . We were in-deed calling for papers describing algorithms, tools, methodologies, and applications that exploit the in-terplay between knowledge and Artificial Intelligence techniques, with a special emphasis on knowledge dis-covery. Accordingly, EKAW 2018 put a special emphasis on the importance of Knowledge Engineering and Knowledge Management with the help of AI as well as for AI. In this way, EKAW 2018 welcomed papers dealing with theoretical, methodological, ex-perimental, and application-oriented aspects of knowledge engineering and knowledge management. In par-ticular, we were expecting papers about methods, tools and methodologies relevant to the following topics: knowledge and AI, knowledge discovery, knowledge management, knowledge engineering and acquisition, social and cognitive aspects of knowledge representa-tion, and applications in specific domains. In addition to this specific focus, EKAW as usual covered all aspects of eliciting, acquiring, modeling, and managing knowledge, the construction of knowledge-intensive systems and services for the Semantic Web, knowledge management, e-business, natural language processing, intelligent information integration, personal digital as-sistance systems, and a variety of other related top-ics. The EKAW 2018 Program Committee, chaired by Catherine Université Côte d’Azur, France, Ghidini Fondazione Italy, received 104 submissions, out of which 36 were accepted for publication in the conference proceedings (34% overall acceptance rate). Four papers were