The Next Generation Information Technologies and Systems (NGITS) wo- shop series is a biannual event held in Israel since 1993. Like its predecessors, NGITS'99 brings together active members of the international research com- nity interested in information technology and knowledge based systems. Many of the base technologies in the traditional areas of database management systems, information retrieval, and resource optimization, are being deployed nowadays in novel systems and applications that ?ourish with the astonishing increase in computational power, storage capacity, communication, and...