Requirements reuse at Danfoss

Requirements engineering is an essential activity in creating embedded real-time systems. Companies that produce a number of partially similar products can reduce development time and cost, improve quality and simplify software maintenance by applying reuse practices. Requirements reuse is an essential enabler to achieve effective software reuse. This study describes two different approaches for requirements reuse at Danfoss. The first approach reuses those requirements that are envisioned to be common between two consecutive projects and allows changing and parameterization of parts of the requirements. The second approach organizes all requirements into a common model and explicitly manages variability and different requirement variants in this common model. The results show that both approaches can result in significant savings in reduced effort by reusing common requirements. The first approach was found to be effective when the domain maturity is low and the significant set of requirements were changed from project to project. The second approach allows high reuse potential and significant savings for stable domains, where most requirements tend to be small additions or minor changes of existing requirements.