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

3.3 Concepts 35
3. creation of a system description that is precise enough to guarantee that the implementation
satisfies the required behaviour;
4. guidelines and heuristics to achieve aims 1,2 and 3.
Concepts for analysis of the problem domain often have the flavour of taxonomy and
philosophy. Analysis is about expressing the nature of things and phenomena, and
about classifying them. Conventional methods focus on finding classes of entities and
the relations that exist between them. A first modelling phase results in a static view
consisting of entities and their attributes. The analysis of dynamic behaviour is postponed
until later modelling phases. For reactive systems this approach is insufficient.
Concepts need to be incorporated to analyse the dynamic behaviour of entities in an early
phase of the modelling process. Figure 3.1 shows attributes, operations and interconnect
structure as three entangled pieces of information of an entity. These three pieces
have static properties as well as dynamic properties. Conventional analysis yields an
inventory of the static properties of an entity (class).
Dynamic properties Static properties
Attributes
Operations
Figure 3.1: Entity Properties
Interconnect
structure
Concurrently the dynamic properties, such as the temporal behaviour, must be analysed.
Temporal behaviour determines how operations transform attributes, how operations
require communication via the interconnection structure and how the structure of links
changes dynamically.
Besides concepts that capture the essentials of the problem domain, additional concepts
are required for architecture design and implementation modelling. These concepts
are quite different and require different accompanying notations than those for analysis.
Examples of concepts that support implementation modelling include architecture,
distribution, boundaries, channels and topology.