. If the validation succeeds, the code is guaranteed to respect the safety policy without relying on run-time checks. The main practical difficulty of PCC is in generating the safety proofs. In order to gain some preliminary experience with this, we have written several network packet filters in hand-tuned DEC Alpha

transformation capabilities that extends run-time entities with higher-level abstract views, in order to enable inspection in terms of the original and most relevant abstractions. Our solution is lightweight in terms of performance overhead and agile in the sense that it can selectively (and on-demand) generate

, we focus on systems in which composition is affected by run-time behaviour of the system. This is the case in pervasive systems where a client interacts with a specific service by using new communication channels dynamically created. These are of special interest to allow private interaction between

-class entities in the development of applications, though they have not, to date, been sufficiently taken advantage of in runtime adaptation specification. In many existing approaches, designers are required to consider the execution model when specifying any runtime adaptation, forcing them to understand

profiling mechanisms that can exist either as a pre-processor that gathers circuit information prior to the circuit validation process, or as run-time entities that allow MVP to learn from its progressive experience.

implementing code. Current development approaches focus on components as the central development entity, leaving component integration as a separate and error-prone task in later stages of the system development process. This approach is particularly problematic in the area of Qualityof-Service properties

level. Our connectors are run-time entities which control the interaction of components and can express a rich repertoire of interaction relationships. We show how connectors can be reused and how they enhance the reuse of components. 1 Introduction In modeling software architectures Allen and Garlan

developers to deploy systems that can refer to entities not identified at the time when the Grumps system and application-level code were implemented. Examples detailing how the topology of a Grumps system may be changed at run-time and how new object implementations may be distributed during system

understanding of the underlying mechanisms of HLA implementations, called RTI's (Run Time Infrastructure) 1 (HLA 1999). The first critical step of this initiative was to develop our own RTI from the HLA specifications. In order to achieve a step by step validation of the RTI, and to evaluate the cost

succeeds, the code is guaranteed to respect the safety policy without relying on run-time checks. The main practical di culty of PCC is in generating the safety proofs. In order to gain some preliminary experience with this, we have written several network packet lters in hand-tuned DEC Alpha assembly