Aspect-oriented concepts are currently introduced in all phases of the software development life cycle. However, the complexity of interactions among different aspects and between aspects and base entities may reduce the value of aspect-oriented separation of cross-cutting concerns. Some interactions may be intended or may be emerging behavior while others are the source of unexpected inconsistencies. Thus, it is desirable to detect inconsistencies as early as possible, preferably at the modeling level. We propose an approach for analyzing interactions and potential inconsistencies at the level of requirements modeling. We use a variant of UML to model requirements in a use-case driven approach. Activities, which are used to refine use cases, are the join points to compose cross-cutting concerns. The activities and their composition are formalized by using the theory of graph transformation systems, which provides analysis support for the detection of potential conflicts and dependenc...