Publication: IEICE TRANSACTIONS on Information and Systems Publication Date: 2001/10/01 Vol. E84-DNo. 10pp. 1302-1312 Type of Manuscript: Special Section PAPER (IEICE/IEEE Joint Special Issue on Autonomous Decentralized Systems and Systems' Assurance) Category: Electronic Commerce Keyword: decentralized database, query language, query processing, electronic commerce (EC), XML,