The SR model is a graph, with several types of nodes and links that work together to provide a representational structure for expressing the rationales behind dependencies. The actors with the SD model are “opened up” to show their specific intentions. There are four types of nodes, based on the same distinctions made for dependum types in the SD model: goal, task, resource, and softgoal. There are three main classes of links internal to the i* actor: means-ends links, task decomposition links and contribution links.
SR diagrams open up Actors and show all the internal elements, including Goals, Softgoals, Tasks, and Resources that contribute to the analysis of alternatives and fulfillment of the dependencies. Goals and Softgoals can be attributed to not only human Actors, but also to non-human Actors (systems, machines, etc.) by the humans. For example, an email system (a non-human Actor) wants to be reliable, fast, and easy, because the humans who initiated these requirements or designed the system attribute these goals to the email system’s design.
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