Specification of Reactive Hardware/Software Systems - Electronic ...

13.2 P.H.A. van der Putten’s Contributions 407
Objects, clusters and channels support formalisation of architecture and implementation
structure. Representations are defined consistently with formal structure
description in POOSL.
Hierarchy, hiding, functionally decomposed scenarios and multidisciplinary scenarios
enable coping with complexity.
Graphical notations are complemented by textual descriptions, such as decision
statements, scenario narratives and system dictionaries.
Method framework
An activity framework has been developed that:
guides the designer from idea to formal model by giving orientation as well as
guidelines and heuristics;
separates a specification in an essential specification and an extended specification;
offers system modelling in different views as well as in a unified model that
formalises a part of the information in the other views;
four different types of views are represented in graphical diagrams:
– object collaboration in scenarios (Message Flow Diagrams and Scenario Narratives);
– classes and relations (Object Class Diagrams);
– physical or logical system structure (Architecture Structure Diagrams);
– formal system structure (Instance Structure Diagrams);
uses textual representations, combined in a Requirements Catalogue, for the description
of design decisions, environmental requirements and entities of the problem
domain;
invites to create a well-designed system structure based on physical and logical
constraints, on possible prescribed implementations and according to the structure
of the problem domain; structure does not emerge from coincidental functional
decomposition;
offers a balanced approach for finding objects by looking both at classes and
instances;
uses scenarios for focusing on various forms of functionality as well as on various
multidisciplinary views on functionality; scenario narratives are used for the description
of dynamic behaviour, ordering and causality; they prepare the formal
description of behaviour in POOSL.