Developing complex, safety critical systems requires precise, unambiguous specification of requirements. A formal specification language is thus well suited to this task. Formal specification languages require, but also exacerbate, the need for tools. In particular, tools should support the elaboration (how to build the formal specification?) and the validation (how to check the adequacy of the specification towards the informal needs of the various stakeholders?). This paper focuses on the language Albert II, a formal language designed for the purpose of expressing requirements for distributed real-time systems. It presents two contributions supporting its use. The first contribution aims at improving the elaboration process by providing a method for constructing an Albert II description from scenarios expressing the stakeholders' requirements. These are represented through Message Sequence Charts extended to deal with composite systems. The second contribution takes the form of a req...

. In this paper, we present two logics that allow for specifying distributed information systems, emphasizing communication among sites. The low-level logic D 0 offers features that are easy to implement but awkward to use for specification, while the high-level logic D 1 offers convenient specification features that are not easy to implement. We show that D 1 specifications may be automatically translated to D 0 in a sound and complete way. In order to prove soundness and completeness, we define our translation as a simple map of institutions. Our result may be useful for making implementation platforms like Corba easier accessible by providing high-level planning and specification methods for communication. 1 Introduction Two logics are presented that allow for specifying distributed information systems, emphasizing communication among sites. The low-level logic D 0 offers features that are easy to implement but awkward to use for specification, while the high-level logic D 1 offers...

Requirements Engineering (RE) investigates the impact of a future-oriented change vision, but the move towards this vision must consider a context heavily shaped by the past. As RE becomes a continuous process throughout the system lifecycle, it must achieve an effective combination of envisionment and traceability. In this paper, we describe a scenario-based solution to this problem which is based on an integration of five ingredients: (a) the persistent capture of context in the form of real world scenes captured in multimedia; (b) formal agent-oriented modelling with a semantics that allows distributed interactive animation; (c) message trace diagrams as a medium for exchanging animation test cases and traces; (d) a goal model to control and record the RE process; and (e) a process-integrated tool environment to ensure method-guidance and traceability with as little effort as possible. In addition to the basics of our approach, we also describe its prototypical implementation in the...

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