A deliberation model for design rationale

Design rationale explains the reasoning behind the choice of a specific design decision against a multitude of other alternatives. Design rationale can play an important role during the design process itself and during rework and reuse of existing designs. Most work on rationale however, exists apart from design theory. This thesis integrates the capture of design rationale with the design process.; The thesis develops a conceptual model for the capture of design rationale by identifying deliberation-negotiations and discussions among designers, as the medium of rationale capture. It adds argumentation structure and the concept of a design context to a popular deliberation schema called IBIS (Issue Based Information System). It proposes the use of the mathematical lattice to aid the organization and representation of, design decomposition, partial design solutions, alternatives and design paths. The concept of a task is introduced to capture iteration and other dynamics of the design process. The thesis contends that the representational capabilities of the proposed model and the accompanying rigor will enhance existing design models.