Research on determining TFOMS of complex system

It is difficult to determine testability figures of merit (TFOMs) of complex system at the early development stage because they are affected by system function, performance, reliability, maintainability, life cycle costing, environment, and so on. We indexed a lot of literatures relevant to this research, and found only two models which can be used to determine the TFOMs. But every one has some shortcomings. The first one is based on fault coverage rate and can give a number value too perfect to unpractical; the second is based on Markov model and can only give a much rough value. So it is our object to build other models which would offset these disadvantages. We try to build three models, and the first calculates TFOMs by availability, reliability and maintainability; the second depends on experience of similar system; the last one synthesizes the other four models from indexed literatures and ours, and presents a more reasonable value by analytical hierarchy process (AHP).