A model of an intelligent system is proposed for implementing the control and professional use of a knowledge collections related to subject area of software interfaces with external users. The basis of formalization is an abstract model of an intelligent system. It is based on coordinated and balanced invariants of the knowledge representation formalism model. Invariants set includes classes of morphisms for abstract knowledge processing modelling with morphisms' domains, invariants of the multidimensional architecture of intelligent systems components, which includes intercomponent knowledge flows and processes of knowledge synthesis within components, as well as invariants of control agents for abstract knowledge flows and processes within intelligent systems. The intelligent system knowledge base is presented as subject area ontology by non-ordered series of simple knowledge. Fragments of such ontology are distributed between components of intelligent systems three-dimensional architecture. The basis of such structure based on the dimensions of abstraction, structuring and the level of knowledge addressed to and processed within intelligent system's separate components. The ontologies reflect the ideas about the structures of memory and the processes of thinking used to model the schemes of the professional activity of a specialist. The basis for the formalization of such concepts is the fundamental principles of philosophy, linguistics, cognitive psychology, mathematics, and system engineering. This allows deploying a comprehensive system of classes of information structures and processes for complex knowledge synthesizing that support achievement of various cognitive goals implemented by specialists within professional tasks implementation processes. The goals system includes extraction, analysis and application of knowledge about user interfaces. The variety of such goals is modeled by a high-level implementation pattern system. They are composed of basic types of goals and are implemented using knowledge processing cognitive operations. Knowledge structures in the format of semantic hierarchies are used as a unified representation of knowledge. Cognitive goals are realized by combinations of operations on structured knowledge, adapted to special classes of structures.