Abduction for design

This paper describes a logical design process model and in particular abduction in it. We present our model of design processes that consists of abduction, deduction, circumscription, meta-level inference, and multi-world mechanism. In this model, design is a process of re ning descriptions of design objects. Abduction generates object descriptions as a hypothesis, deduction examines validity of the object descriptions proposed by abduction, circumscription maintains knowledge used in abduction and deduction by resolving inconsistency, meta-level inference provides knowledge for abduction, and multi-world mechanism represents evolution of the object descriptions. Since abduction is crucial part to realize synthesis in design, we clarify the role of abduction in design and develop an abductive inference for design. Here we de ne abduction as a process making integrated hypotheses and theories to explain the given facts. It means that (i) not only hypotheses but also theory to explain facts with hypotheses are important part of explanation, and that (ii) integration should be kept both in hypotheses and in theories. To achieve above features of abduction in a knowledge-based framework, we introduce a segment of explanatory coherence and superposition of proposition. The former shows connectivity of explanations and the latter realizes integration of hypotheses. Since abduction contributes to integration of knowledge, the framework based on abduction gives an answer to deal with variety of knowledge in CAD systems.