Extending PSC for Monitoring the Timed Properties in Composite Services

Due to the dynamically evolving attribute, validation of composite services must be extended from design time to run-time. Dynamical verification techniques, such as runtime monitoring, have been first class activities to be performed during the execution of composite services. For a kind of composite services, nonfunctional properties, such as timed properties, are as important as functional properties and need to be monitored at run-time. However, using traditional logic and formalism, these timed properties are not easily represented for general software engineers. In order to deal with this problem, we first extend a novel notation (Property Sequence Chart) with time constructs. Then, we give its semantics in terms of timed Buchi automata and measure its expressiveness based on recently proposed real-time specification patterns. Finally, we propose a novel framework to monitor two kinds of timed properties in composite services: the accomplished time of basic service operations and some additional timed assumptions of the composition process. Our framework provides a completely graphical front-end which can friendly help general software engineers to monitor the timed properties in composite services.