ABSTRACT
The Advanced Computer Applications group (ACA) of the International Institute for Applied Systems Analysis (IIASA) developed MEXSES, a rulebased expert system for environmental impact assessment of water resources development projects in the Lower Mekong River Basin. The information on which the impact assessment is based, is stored in the system's knowledge base. The knowledge is represented as production rules in the form "IF (condition) THEN (action)". The expert system's inference engine interprets the information in the knowledge base and generates a conclusion about the impact of the problem under consideration. However, in the field of water resources research many mathematical models exist of which MEXSES could not make use since it was initially designed as a "stand alone" expert system. In this paper we describe bow this problem bas been overcome by creating a link between MEXSES and external models so that MEXSES can use the computational power of mathematical models during the inference process.
