Toward a Formal Knowledge System Theory and Its Cognitive Informatics Foundations

Knowledge science and engineering are an emerging field that studies the nature of human knowledge, and its manipulations such as acquisition, representation, creation, composition, memorization, retrieval, and depository. This paper presents the nature of human knowledge and its mathematical models, internal representations, and formal manipulations. The taxonomy of knowledge and the hierarchical abstraction model of knowledge are investigated. Based on a set of mathematical models of knowledge and the Object-Attribute-Relation (OAR) model for internal knowledge representation, rigorous knowledge manipulations are formally described by concept algebra. A coherent framework of formalized knowledge systems is modeled based on the analyses of roles of formal and empirical knowledge. Then, the theory of knowledge acquisition and the cognitive model of knowledge spaces are systematically developed.