i* is an approach developed by Eric Yu and John Mylopoulos for modelling the organizational context of a software system.  Recent work with i* has been done by Neil Maiden and others. 

Figure 1.  i* diagram key

i* diagrams

The nodes and edges in i* diagrams appear in Figure 1. 

Strategic dependency (SD)

A strategic dependency diagram relates actors with needs (“dependers”) to actors with the capability of meeting those needs (“dependees”).  The relations are expressed with dependency edges.  The needs are expressed in terms of goals.  Yu and Mylopoulos use “dependum” to refer to what is needed. 

Strategic rationale (SR)

A strategic rationale diagram describes how actors may achieve goals through tasks.  Subtasks are linked to their supertasks by task-decomposition edges.  Alternative ways of accomplishing a task are linked to the tasks by means-end edges. Subgoals are linked to the goal they help achieve by contribute-to edges. 

References

Maiden+Manning+2005-grsm

N. A. M. Maiden, S. Manning, S. Jones, and J. Greenwood. Generating requirements from systems models using patterns: a case study. , 10(4):276–288, 2005.

Abstract

Academic research has produced many model-based specification and analysis techniques, however, most organisations continue to document requirements as textual statements. To help bridge this gap between academic research and requirements practice, this paper reports an extension to the RESCUE process in which patterns for generating requirements statements from i* system models were manually applied to i* models developed for a complex air traffic control system. The paper reports the results of this application and describes them with examples, the benefits of the approach to the project, and ongoing research to implement these patterns in the REDEPEND modelling tool to make requirements engineers more productive. We review similar work on requirements modelling and expression, and compare our work to it to demonstrate the proposed advance in the state of the art. Finally the paper discusses future uses of requirements generation from model patterns in RESCUE.

doi:10.1007/s00766-005-0010-9

Yu+Mylopoulos1994-erar

Eric S. K. Yu and John Mylopoulos. From e-r to “a-r” — modelling strategic actor relationships for business process reengineering. In 13th International Conference on the Entity-Relationship Approach (ER ’94), pages 548–565, 1994.

Abstract

As information systems are increasingly being called upon to play vital roles in organizations, conceptual modelling techniques need to be extended to relate information structures and processes to business and organizational objectives. We propose a framework which focuses on the modelling of strategic actor relationships (“A-R”) for a richer conceptual model of business processes in their organizational settings. Organizations are viewed as being made up of social actors who are intentional — have motivations, wants, and beliefs — and strategic — they evaluate their relationships to each other in terms of opportunities and vulnerabilities. The framework supports formal modelling of the network of dependency relationships among actors, and the systematic exploration and assessment of alternative process designs in reengineering. The semantics of the modelling concepts are axiomatically characterized. By embedding the framework in the Telos language, the framework can also potentially serve as an early-requirements phase tool in a comprehensive information system development environment.

url

Yu+Mylopoulos1997-embr

Eric S. K. Yu and John Mylopoulos. Enterprise modelling for business redesign: the i* framework. SIGGROUP Bulletin, 18(1):59–63, 1997.

Abstract

Information technologies and systems are instrumental to the rapid changes in organizations and business enterprises today. In turn, these changes are creating needs for new concepts and methods for information systems engineering. As the cycle of interaction between technological change and business environment change tightens, there is increasing need to relate information systems decisions more directly to business goals and objectives.

Traditional modelling techniques such as those based on structured analysis and entity-relationship modelling focus on the modelling of activities, entities, and flows. These models describe what an enterprise is like, or how it operates, but they cannot express why it is the way it is. The motivations, intents and rationales behind the activities and flows are missing. To complement these existing models, we need new ones that model the strategic relationships among organizational stakeholders, so that their motivations and intents (the “whys”) can be reasoned about. These models can be used to assist in the search for innovative solutions to business problems, and to identify what enabling roles information systems can play in new business configurations.

doi:10.1145/271159.271180 url

The i* wiki.