AUCS TR Reusable Components for Knowledge Base and Database Integration

Organisations increasingly need to integrate their database and knowledge based systems into an enterprise wide information system This need applies to both new and legacy database and knowledge based systems This paper argues that modern middleware technology notably Java and CORBA provides an e ective integration medium particularly when combined with software agent technology De ning the components of an enterprise information system as software agents provides a degree of uniformity which facilitates integration Java and CORBA middleware provide a solid platform on which to implement the agent based architecture The paper is illustrated with an example of a medical information system prototype featuring the integration of a number of SQL databases and a CLIPS knowledge based system integrated by lightweight and reusable Java CORBA components Middleware for Information Integration There is currently considerable interest in using middleware technology to integrate sources of data and knowledge Some of these sources are legacy systems pre existing databases and expert systems while others are custom built services speci cally de signed to operate as components within distributed information architectures Some of the common scenarios served by such architectures are extracting data from databases and providing it as the input to knowledge based systems which in turn derive new information extracting data from databases and knowledge from knowledge bases and com bining both to compose a new information source extracting and transforming data and knowledge into constraint programs the solution of which yields new information Some example instantiations of these scenarios in actual application domains are distributed engineering design where data on components is combined with know ledge of how designs are composed and constraints given by the customer s re quirements for example con guring a modular computer system medical informatics systems where patient data is fed into expert systems for therapy recommendation or critiquing for example recommending appropriate drugs based on the patient s needs and current drug usage University admissions systems where appropriate programmes of study can be o ered based on the student s needs and consistent with data on their academic history for example knowledge of prerequisites can be checked against the stu dent s database entry from their previous institution The technology push behind these kinds of integrated application originates in projects such as the Knowledge Sharing E ort KSE and the Stanford Mediators work of the early s In particular the KSE work has popularised the notion of viewing information sources as software agents which interoperate using an agent communication protocol such as KQML KQML supports both the transmission of information data and knowledge statements and the co ordination and control as pects of a distributed information system The Mediators work has promoted the idea of a three layer information systems architecture in which top layer user interface components access the bottom layer information sources through a middle layer of mediator components These mediators are considered to add value to the informa tion for example by fusing ltering or sorting the source data and knowledge Additional impetus has been provided by the widespread adoption of internet tech nology which has made the implementation of distributed information systems much more straightforward by providing a standard network platform the TCP IP protocol stack More recently higher level programming paradigms have emerged to support the development of platform independent interoperable software components on TCP IP internetworks Termed middleware technologies such as Java and CORBA o er an e ective means of glueing heterogeneous applications together