Mobile agents in a distributed heterogeneous database system

The purpose of this paper is to present a new infrastructure for multimedia database searches based on CORBA and mobile agent technology. A new mobile agent system, called Vagabond, was implemented in pure Java using only standard CORBA facilities. The fundamental agent design and architecture is introduced. Measurements demonstrated the merits of Vagabond, namely the simple design, the implicit heterogeneity inherited from CORBA, and its speed. The system (renamed as M³) was implanted inside an Oracle8i database system which is able to run Java code as a stored procedure. Further measurements have justified the idea presented above, ie. sending agents directly inside the database can decrease the response time of multimedia content search and retrieval. However, the required modifications made the embedded agency accessible for clients using only Aurora, Oracle´s modified Visi-broker ORB. On the basis of the Proxy design pattern, the paper presents a proxy solution that encapsulates the specific protocol issues that restricted interoperability, and thus provides the user of the infrastructure with the benefits of a truly heterogeneous environment