: In this paper the architecture of the VITAL-KR is described. Author: Enrico Motta and Arthur Stutt Collaborators (VITAL Partners): SYSECA - SYSECA TEMPS REEL (Coordinator) * NOTT - UNIVERSITY OF NOTTINGHAM * BULL - BULL CEDIAG AC - ANDERSEN CONSULTING ONERA - ONERA PTT - ROYAL PTT NEDERLAND NV * OU - THE OPEN UNIVERSITY * NOKIA - NOKIA RESEARCH CENTER * marked partners are involved in this task page 1 _____________________________________________________________________ The Open University 1991 1. INTRODUCTION As discussed in (Motta, 1991) both the current practice of industrial KBS, and the consensus among researchers (Frisch & Cohn, 1991) suggest that hybrid architectures, embedding a number of specialized representations/reasoners, are required to enable knowledge engineers to build efficient and powerful KBs. This is due to the fact that it has been recognized that no universal knowledge representation language exists, which can efficiently model all types of proble...