[The use of inexact reasoning method for differential diagnosis of pulmonary function]

This article expounds the main idea of the evidence theory and hence presents a mathematical model. Based on the above work, we have developped a computer-aided medical differential diagnosis system with Visual Basic. The system can identify restrictive ventilatory impairment, obstructive ventilatory impairment, mixed ventilatory impairment and normal. according to the valuse of patients' related indexed. In a retrospective test of 290 cases we collected, the rate of agreement between the diagnosis made by this system and the physicians was 93.1%.