  In dynamic architectures, component activation and connections between
components may vary over time. With the emergence of mobile computing such
architectures became increasingly important and several techniques emerged to
support in their specification. These techniques usually allow for the
specification of concrete architecture instances. Sometimes, however, it is
desired to focus on the specification of constraints, rather than concrete
architectures. Especially specifications of architecture patterns usually focus
on a few, important constraints, leaving out the details of the concrete
architecture implementing the pattern. With this article we introduce an
approach to specify such constraints for dynamic architectures. To this end, we
introduce the notion of configuration traces as an abstract model for dynamic
architectures. Then, we introduce the notion of configuration trace assertions
as a formal language based on linear temporal logic to specify constraints for
such architectures. In addition, we also introduce the notion of configuration
diagrams to specify interfaces and certain common activation and connection
constraints in one single, graphical notation. The approach is well-suited to
specify patterns for dynamic architectures and verify them by means of formal
analyses. This is demonstrated by applying the approach to specify and verify
the Blackboard pattern for dynamic architectures.
