Requirements engineering for complex collaborative systems

A method for analysing requirements for complex sociotechnical systems is described. The method builds on the I* family of models by explicitly modelling communication between agents by discourse act types. System (i*) models and use cases are developed which describe the dependencies between human and computer agents in terms of a set of discourse acts that characterise the obligations on agents to respond and act. For human-computer communication, the discourse acts indicate functional requirements to support operators. For human agents, the acts specify their obligation to act and constraints on action. The method provides analytic techniques and heuristics to assess agent workloads in terms of the tasks and communication they have to perform. Scenarios are run against the system model by walking through the chain of operator tasks and communication links to produce time estimates and failure probabilities, where the demands of scenarios impose excessive loads on human operators. The method is illustrated with a case study of a naval command and control system