21. Logic programming languages that include this extension have the knowledge representation capabilities of a non-monotonic logic. 22. He was appointed full professor in 2002, and is leading the Knowledge Representation and Reasoning Group. 23. A knowledge representation language may be sufficiently expressive to describe nuances of meaning in well understood fields. 24. Kurzweil surveys the vision, and knowledge representation , as seen in language, are two key components of intelligence. 25. A key trade-off in the design of a knowledge representation formalism is that between expressivity and practicality. 26. Metaclasses thus enhance the expressivity of knowledge representations in a way that can be intuitive for users. 27. Although these representations are mathematically neat, they tend to be unsuitable for knowledge representation in expert systems. 28. For example, the Web Ontology Language ( OWL ) employs several layers of logic-based knowledge representation systems. 29. For his doctoral thesis, he focused on musical knowledge representation , machine learning of music and software sound synthesis. 30. However, FOL has two drawbacks as a knowledge representation formalism : ease of use and practicality of implementation.
