Dependency analysis in constraint negotiation

Problems in engineering design are constraint-oriented and often involve multiple perspectives. Designers must consider not only functional requirements of a product but also its life-cycle perspectives. Each perspective has its own set of constraints which may contain conflicting or unsatisfied requirements. A human designer cannot be aware of all constraints and design alternatives all the time. The objective of this paper is to develop a methodology to assist designers in negotiation of constraints. A network model is proposed to represent relationships among design variables. An algorithm is developed to derive dependencies between design variables and goals. Based on the dependencies obtained, design modifications are generated for resolving conflicts. In the second part of the paper, a fuzzy-logic-based approach is used to model imprecise dependencies between variables in the case when no sufficient quantitative information is available. The approach proposed can be used to increase the amount of information provided to the designers for making decisions.