Object-oriented design of decision support systems in natural resource management

Abstract Two design models, one object-oriented (OO) and the other procedure-oriented (PO), were developed for a forest pest management decision support system (DSS) to simulate the pattern of functional computer code reusability during system evolution. Each design model was constructed using the Nexpert Object expert system development shell. The OO design used the real-world model of the application domain as the mechanism to connect DSS subsystems, whereby subsystem functions became class methods. Simulations were conducted to compare the change in proportion of reusable code among PO and OO approaches as applications were added to the DSS for ten sequences of system development. Analysis showed that the OO design had a small but significant increase in code reusability. There were indications that if class methods became selectable through polymorphism combined with dynamic inheritance, the superiority of the object-oriented design would become greater. Opportunities to take advantage of this feature may not be available until the DSS reaches a large size.