PAD-BASED: Prototypes and delegation based approach to knowledge organization in expert system design

Scope and method of study. The object-oriented approaches to computing provide major contributions in most computer research including artificial intelligence. This rapid growth is attributed to its four significant properties: the principles of program modularity, information hiding, data abstraction, and code reusability. The concept of modularity has been widely introduced into expert system design and development. Various techniques have been developed by incorporating class/subclass, inheritance, delegation, and polymorphism concepts to knowledge base structure and knowledge representation techniques. Although these approaches are successfully used in expert system design, the issues of extensive development time, and limited knowledge sharing and re-use among expert systems are still open problems, particularly when developing expert systems in small computer environment with limited memory. The scope of the study is to develop an expert system development methodology to address the above problems.;Findings and conclusions. The object-oriented approach based on the concepts of prototype and delegation mechanism is used to develop a new model (PAD-BASED model) serving as the knowledge organization technique in expert system design. Its prototype structure provides a high structurability in knowledge base organization. The delegation mechanism allows dynamic interactions among prototypes contributing to an alternate memory management scheme in small computer system as well as a high opportunity for knowledge sharing and re-use among structured expert systems. Agricultural applications are implemented based on the PAD-BASED model. The PAD-BASED development life cycle model is used to support the management of complex interactions among the experts during the expert system development. The advantages of the PAD-BASED model are described fully as well.