Research On FMEA For Object-Oriented Software

As a traditional method of reliability and safety, FMEA (Failure Mode and Effect Analysis) has been widely applied to the reliability engineering of the hardware. With the development of digital revolution, software FMEA was proposed and used in the process of design and implementation for software product gradually, improving the reliability of the safety critical software effectively. But traditional methods of software FMEA have some defects, such as low accuracy, poor objectivity and lack of automatized analysis tools. Meanwhile, because the software FMEA method has played a very important role and achieved good results in the reliability and security analysis of the safety critical software, so we consider to extend the FMEA method to common software development process. Aimed at the object-oriented software design methods which has been widely used, we want to search a FMEA approach for object-oriented software to deal with existing problems and satisfy the demands, the thesis analyzes the characteristics of the object-oriented software, extract the specific failure models of object-oriented software, and try to give an object-oriented software FMEA analysis method based on the dependence, which can track the whole developing process of software, improve the reliability of the software, and provide a basis for designing the Computer-aided tools.First, this thesis proposed an approach of system level software FMEA which based on the UML model. In the early time of software development, viz. phase of demand analysis and summary design, we utilize the UML model to understand the system, through defining and building the UML dependence model to display the whole target system, then based on this model we proposed an approach of failure cause and effect analysis which using the algorithm to find the accessible nodes of graph.Second, this thesis proposed a method of detailed level software FMEA which based on the dependent relations of program. On the stage of detailed design stage and the realization of the code, we defined and built the Java system dependent graph, which can show the complex dependent relations of code and provide the basis of detailed level of software FMEA. And based on the slice idea we can analyze the detail level software failure causes and effects.The key and foundation of analysis above is to extract the failure models. This thesis give a collection method of failure models based on the heuristic rule. The heuristic rule contains three aspects, viz. extract the classical failure models based on the failure model library of object-oriented software, extract the failure models through the UML models and extract the failure models based on the specific requirements and specifications of the target system. Then on the basis of this, we give the integrated method for system level software FMEA and detailed level software FMEA. These two processes integrated closely.Finally, based on the theoretical analysis, we design and realize the prototype of the assisted analysis tools of software FMEA. And though a case study to verify the feasibility of object-oriented software FMEA , and the accuracy of the assisted tools.