New multimedia applications have emerged on top of information infrastructures, such as on-demand services, digital libraries and museums, online shopping and document management, which require new databases. That is, next-generation database systems must enable users to efficiently and flexibly develop and execute such advanced multimedia applications. We focus on development of a database system which enables flexible and efficient acquisition, storage, access and retrieval, and distribution and presentation of large amounts of heterogeneous media data. We take an approach based on an object-oriented database, which is more suitable for the description of media structures and operations than a traditional relational database. We extend the object-oriented approach by providing temporal and spatial operators, and control of distributing computing and QOS (quality of service). In this paper, we describe a multimedia data model and its efficient implementation.

The methods of fast hypothetical reasoning systems developed for propositional logic cannot be applicable in a straightforward manner to the predicate-logic case. A fast hypothetical reasoning mechanism that is effective for predicate-logic knowledge (actually for function-free predicate Horn-clause knowledge) is presented. A reasoning method developed in the deductive database area is effectively applied to this mechanism.>