Development of a car seat: A case study using AUTOFOCUS, DOORS, and the Validas Validator

Abstract

In this paper we describe the modeling process and the resulting model of a typical car seat. The requirements of this seat are documented in [Chr00] which are the input of our process. We used the tools AUTOFOCUS [AF-02], DOORS [Tel02], and Validas Validator [Val02]. Starting with requirements analysis we develop first model fragments. Afterwards the graphical, component oriented approach of AUTOFOCUS is used to model the system. Requirements management and tracing techniques ensure that all requirements are implemented. The model-based core of the development process helps very much for the requirements tracing. The model fragments of the earlier phases can be updated so that tracing information is consistent. Compared to traditional requirements tracing techniques less manual interaction is needed. Beside this the test management is also done based upon the requirements. For relevant requirements test cases are specified. This is done using the AUTOFOCUS notation of Extended Event Traces (EETs) a variant of Message Sequence Charts (MSCs). Afterwards the generated code of the model is tested based upon those test cases. Further validation techniques like simulation, consistency, and determinism checks of the Validas Validator have led to the detection of inconsistencies in the model and in the specification.