1. A recursive mapping structure for diagnostic models interpreted by at least one diagnostic reasoner, comprising: a parent diagnostic model, including: a first input module, a first output module, a first monitor module coupled to the first input and first output modules, and a first propagation module coupled between the first input and first output modules; and a child diagnostic model, including: a second input module, a second output module, a second monitor module coupled to the second input and second output modules, and a second propagation module coupled between the second input and second output modules, wherein the second monitor module is coupled to the first monitor module.