Modeling timing requirements in Problem Frames using CCSL

As the embedded systems are becoming more and more complex, requirements engineering approaches are needed for modeling requirements, especially the timing requirements. Among various requirements engineering approaches, the Problem Frames(PF) approach is particularly useful in requirements modeling for the embedded systems due to the characteristic that the PF pays special attention to the environment entities that will interact with the to-be software. However, no concern is given on timing requirements of the PF at present. This paper studies how to add timing constraints on problem domains in the PF. Our approach is to integrate the problem representation frame in the PF with the timing representation mechanism of MARTE(Modeling and Analysis of Real Time and Embedded systems). A unified problem frame modeling process integrated with timing constraints is provided, and problem frame requirements with timing constraints expressed by MARTE/CCSL(Clock Constraint Specification Language) and clock construction operators are obtained.