The first contribution of this thesis has been to extend the SiFA paradigm with the concept of a parameter block. The parameter block enables knowledge about the design to be presented explicitly, and defines very precisely the knowledge that is required in the design process. It also allows multiple levels of meta-knowledge to be represented, through the idea of levels of reference.
The second main contribution is the analysis of conflicts in the SiFA framework. Since SiFAs provide the building blocks of a multi-agent design system, the conflicts between them represent the primitives of conflict situations in any design.
The conflict hierarchy first divides conflicts into two broad categories: incompatibility conflicts and criticism conflicts. These are further divided according to the kinds of entities involved in the conflict. This hierarchy enables general methods for handling the various tasks involved in the negotiation process, i.e., a method for detecting incompatibility conflicts will work for a whole group of conflicts under the incompatibility conflicts branch of the hierarchy.
The third major contribution of the thesis is the negotiation model defined for the SiFA paradigm. The negotiation process was divided into many steps, conflict indication, detection, classification, strategy selection, refinement, and execution. Most of these tasks turned out to be relatively simple problems for a SiFA to solve since the kinds of conflicts an agent could be involved in are few, and are very well specified. Once these steps were identified, the negotiation knowledge that should be present in an agent was also identified. Each agent had to have knowledge and methods to be able carry out all of these negotiation steps.
These contributions were also demonstrated by a simple wine glass design system COSINE which used these ideas to come up with a design, taking into account many different and conflicting points of view.