A requirements specification method for adaptive real-time systems

Design Specifications for Adaptive Real-Time Systems

“…By contrast, the failure of data to arrive at an alternative input port need not necessarily block the progress of the task. Rather, this corresponds to one possible branch through the task's restricted activity graph; the arrival of data is only required when it serves to enable an activity that has arrived [7]. An output port represents a logical location through which outputs are to be delivered upon execution of a given activity.…”

“…The control flow model is expressed with a task graph in which each vertex represents a runtime entity, i.e., a task or an input/output data element, and each arc represents the data production/consumption relations between two communicating entities. The sequential program model is expressed with a restricted activity graph which is a subgraph of an activity graph representing the requirements specification [7]. Graphical notations are used for representing relations between data items in a data model, relations between two communicating entities and the temporal/spatial parallelism of inputs/outputs of each entity in a control flow model, and the internal computational structure of a sequential program model (i.e., a task).…”