Refactoring the Whitby Intelligent Tutoring System for Clean Architecture

Abstract Whitby is the server-side of an Intelligent Tutoring System application for learning System-Theoretic Process Analysis (STPA), a methodology used to ensure safety anything that can be represented with systems model. The underlying logic driving reasoning behind Situation Calculus, which many-sorted situation, action, and object sorts. Calculus applied Ontology Authoring Contingent Scaffolding: primary activities within Whitby. Thus many fluents actions are aggregated in from these two sub-applications itself, but all available through common situation query interface does not depend upon any or actions. Each STPA project single term, queried include ontology, determine what pedagogical interventions offer. Initially was written Prolog using module system. In interest cleaner architecture implementation improved code reuse extensibility, initial refactored into Logtalk. This refactoring includes decoupling reasoner, framework, Scaffolding framework third-party libraries reused other applications. extraction achieved by inverting dependencies via Logtalk protocols categories , reusable interfaces components provide functionally cohesive sets predicate declarations definitions . this paper architectures iterations evaluated respect motivations refactor: clean enabling extensibility.