Brambilla, M.; Deutsch, A.; Sui, L.; Vianu, Victor. 2005. The role of visual tools in a web application design and verification framework: A visual notation for LTL formulae. 5th International Conference on Web Engineering (ICWE). Pages 557-568. (Abstract) (Online version)
As the Web becomes a platform for implementing complex B2C and B2B applications, there is a need to extend Web conceptual modeling to process-centric applications. In this context, new problems about process safety and verification arise. Recent work has investigated high-level specification and verification of Web applications. This relies on a formal data-driven model of the application, which can access an underlying database as well as state information updated as the interaction progresses, and a set of user inputs. Properties verified concern the sequences of events, inputs, states, and actions resulting from the interaction. For the purpose of automatic verification, properties are expressed in linear-time or branching-time temporal logics. However, temporal logics properties are difficult to specify and understand by users, which can be a significant obstacle to the practical use of verification tools. In the present paper, we propose two alternative visual notations for specifying temporal properties. One alternative is to restrict the sequences of events using existing workflow specifications, such as BPMN, describing the execution flow of tasks within the application. However, such workflow formalisms have limited ability to express temporal properties. Another alternative is to develop a visual approach for explicitly specifying temporal operators, thus recovering their full expressiveness.