The Role of Visual Tools in a Web Application Design and Verification Framework: A Visual Notation for LTL Formulae

Abstract

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.

Model-Driven Design of Audiovisual Indexing Processes for Search-Based Applications

“…Data Analysis), and possibly a SubType (2), which further refines the Type information (e.g., Music Genre Analysis). An activity is parametric, and has a (possibly empty) set of input parameters (3) and a (possibly empty) set of output parameters (4).…”

“…Suppose that the process of Figure 3 contains the following guard predicate for activity AnalyzeFace: P(X):= (X.duration<=1200) to state that the face recognition component should be called only for short videos. Then, the expression for the output of the AnalyzeFaces activity would become: 2 The dot notation is used to select parameters by name when the output of an activity is composite.…”

Process Modeling in Web Applications

“…Verifying that the process enacted by a given hypertext coincides with a desired process specification is a very difficult problem [Deutsch et al 2004;Brambilla et al 2005], tackled more effectively when the process control features are made explicit in the hypertext model. In summary, explicit control is suitable for complex multi-actor processes, where the presence of an explicit representation of the data and hypertext features stemming from the process model makes it easier to reason about cases, and to maintain and extend the application.…”

Specifying and Validating Data-Aware Temporal Web Service Properties

“…In particular, it can be used to express safety, fairness, and liveness properties, and sequentiality properties in UML Sequence Diagrams. The three operators of the Let's Dance choreography language ("precedes", "inhibits" and "weak-precedes") [9] can be mapped into CTL-FO + , as well as all the existence and relation formulae of the DecSerFlow language [41], and the portion of BPMN and BEMN which has been formalised into temporal logic [42]. It can also express properties that are beyond any of these languages, such as all data-aware constraints.…”