A group formation support system based on substitute goods in group buying

In electronic marketplaces, group buying is seen as an effective form of electronic commerce and a promising field for applying agent technologies. We study decision support systems for buyers in group buying. In group buying, when buyers cooperate with each other, a seller can discount the price of a good. In many existing group buying sites, some sellers deal in the same sort goods or their imitations. Buyers form coalitions for each item on sale. Buyers cannot always purchase goods at a lower price, because the buyers' subgroups are distributed. Buyers need to search hard to find goods they can purchase. In this paper, we propose a group buying marketplace on the Internet. In our marketplace, buyers can purchase goods at a lower price by forming coalitions. Our system can provide a service in which buyers are integrated based on their multiattribute preferences (utilities). Our system supports buyers' decision making by using the Analytic Hierarchy Process. We propose three methods for group integration. First, buyers trade in simple group buying. Second, all buyers are integrated. Third, some buyers are integrated. The advantages of our market are that buyers' multiattribute utilities are effectively expressed in group integration and buyers can purchase goods at a lower price. Buyers' payments are decided based on their degree of compromise. A successful seller can sell goods in their stock.