Abstract
This paper introduces the simulation system that helps and suppotrs the parties concerned when they negotiate to make a decision. The negotiation model works by modifying the utility function for a compromise in the decision making process of the utility theory. The simulation method based on the fuzzy decision making is suggested to find out the solution or the compromising point that would satisfy both sides. In principal one party's concessive degree is decided by considering the opposite party's concessive degree and also the adherence to each arrtibyte. To find out the most appropriate concessive rule for a compromise out of a large number of those rules, tuning by genetic algorithm is practiced. And the paper discusses that the fuzzy rule is tuned in pracite by genetic algorithm and then the potimum rule is derived. As a concrete example of the simulation, group car buying decision is dealt with for showing its actual process and the results. All the results suggest that this method is expected to be very efficient in searching for a compromising point to avoid an explosion of combinations of solutions available.
