Self-adaptive software systems are those able to manage changing operating conditions dynamically and autonomously. Currently, most proposals in this field rely on an explicit representation of the constituent elements and goals of the system. This approach is suitable for systems where constituent elements are well known at design time. However, in systems where new elements may dynamically enter or leave the execution environment, it is not possible to obtain a predefined description of the system's architecture nor a complete specification of its goals. Paradigmatic examples of such systems can be found in ubiquitous computing, or dynamic web service discovery and composition, where new adaptability problems arise, such as the (dis)connection of unforeseen elements to an already running system, or ensuring properties of the composition among services, which cannot be addressed at static verification time since the state space of the system is not closed anymore. In this paper, we present our approach for the composition and resolution of interface mismatch among services in ubiquitous computing environments, dynamically reconfiguring the system as new services are integrated or disconnected.