i* Guide
Version Number | Date | Author(s)
|
| 3.0 | August, 2007 | Samer Abdulhadi |
| 2.0 | October, 2006 | Jennifer Horkoff, Eric Yu |
| 1.0 | August, 2006 | Gemma Grau |
i* Guide
Welcome to the main page for the i* Guide. The Table of Contents (TOC) below provides access to all the Wiki Pages covering all the sections and i* guidelines. The house icon (
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- 1 Purpose
- 2 Using the Guidelines
- 3 Summary of i* Notation
- 4 Strategic Dependency (SD) Model
- 5 Srategic Rationale (SR) Model
- 6 Naming, Icons, and Colors
- 7 Scaling
- 8 Level of Complexity
- 9 Model Analysis
- 10 Methodology
- 11 Acknowledgments
- 12 References
- 1 Purpose
- 2 Using the Guidelines
- 3 Summary of i* Notation
- 4 Strategic Dependency (SD) Model
- 4.1 Actors
- 4.2 Actor Association Links
- 4.3 Strategic Dependencies
- 4.3.1 Goal Dependency
- 4.3.2 Task Dependency
- 4.3.3 Resource Dependency
- 4.3.4 Softgoal Dependency
- 4.3.5 One-Side Dependency
- 4.3.6 Guideline (Intermediate,Concept and Evaluation) Use the Dependency link to indicate a Strategic Dependency relationship between Actors.
- 4.3.7 Guideline (Beginner,Notation) Use the “D” symbol notation to denote a Dependency Link.
- 4.3.8 Guideline (Beginner,Concept) Do not use Dependency Links inside an Actor.
- 4.3.9 Guideline (Beginner,Concept) Ensure that both sides of a Dependency Link point in the same direction.
- 4.3.10 Guideline (Intermediate,Concept & Evaluation) Do not reuse Dependums in more than one Dependency Relation.
- 4.3.11 Guideline (Beginner,Concept) Do not use a Dependency Link between two actors without showing the Dependum.
- 4.3.12 Guideline (Beginner,Layout) Avoid or minimize drawing intersecting Links and overlapping Links with other Links and elements' text.
- 4.3.13 Guideline (Beginner,Layout) Make both sides of a Dependency Link look like a single, continuous curve as it passes through the Dependum.
- 4.3.14 Guideline (Beginner,Layout) Spread the connection points of Dependency Links out on an Actor.
- 4.3.15 Guideline (Beginner,Layout) Keep elements horizontal. Do not tilt or twist them.
- 4.4 Vulnerability
- 4.5 Strategic Dependency Example Model: Buyer Drive E-Commerce from Yu01
- 5 Srategic Rationale (SR) Model
- 5.1 Boundary/Actor Boundary
- 5.1.1 Guideline (Beginner,Layout) Avoid or minimize overlapping boundaries of Actors where possible.
- 5.1.2 Guideline (Beginner,Layout) Keep Dependency Links outside the boundaries of Actors.
- 5.1.3 Guideline (Beginner,Layout) Use the conventional Actors’ boundaries (circles) unless other shapes can improve the overall layout.
- 5.2 Elements/Nodes
- 5.2.1 Goals (Hard Goals)
- 5.2.1.1 Guideline (Beginner,Concept) Use a Softgoal for quality criterion and use a (hard) goal for a sharply defined objective.
- 5.2.1.2 Guideline (Beginner,Concept) Do not confuse Softgoal with optional, less important Goals.
- 5.2.1.3 Guideline (Beginner,Concept) To indicate that a Goal can be achieved by performing several sub-tasks, model the decomposition by introducing a Task.
- 5.2.1.4 Guideline (Beginner,Concept) Use multiple Means-End Links from Tasks to a Goal to indicate alternatives.
- 5.2.1.5 Guideline (Beginner,Concept) Don’t mix Goals and Tasks in the Means-Ends links.
- 5.2.1.6 Guideline (Beginner,Naming) Use precise language to name a Goal or a Task.
- 5.2.1.7 Guideline (Beginner,Concept) A Goal can only be decomposed using Means-Ends Links.
- 5.2.2 Softgoals
- 5.2.3 Tasks
- 5.2.4 Resources
- 5.2.5 Beliefs
- 5.2.6 Guideline (Beginner,Layout) Avoid overlapping elements inside or outside Actors.
- 5.2.7 Guideline (Beginner,Layout) Connect each Strategic Dependency Link in an SR model to the correct element within the actor.
- 5.2.8 Guideline (Beginner,Layout) Adopt or follow a consistent direction for the goal refinement/decomposition hierarchy as much as possible.
- 5.2.9 Guideline (Beginner,Layout) Do not draw SR model elements outside the boundaries of the corresponding actors.
- 5.2.10 Guideline (Beginner,Layout) Unconnected elements within an Actor is indicative of an incomplete model.
- 5.2.1 Goals (Hard Goals)
- 5.3 Means-Ends Links
- 5.4 Decomposition Links
- 5.4.1 Guideline (Beginner,Concept) Be consistent with the direction of the Task Decomposition Link between a Task and sub Task or Resource.
- 5.4.2 Guideline (Beginner,Concept) Be consistent with the direction of the Task Decomposition Link between a Task and a Softgoal.
- 5.4.3 Guideline (Beginner,Concept) Do not extend Decomposition Links beyond the boundaries of actors.
- 5.4.4 Guideline (Beginner,Concept) Don’t use the Task Decomposition Link or Means-End Link to refine Softgoals.
- 5.5 Contribution Links
- 5.5.1 Make
- 5.5.2 Some+
- 5.5.3 Help
- 5.5.4 Unknown
- 5.5.5 Break
- 5.5.6 Some-
- 5.5.7 Hurt
- 5.5.8 Or
- 5.5.9 And
- 5.5.10 Guideline (Beginner,Concept) Use Contribution Links from any element only to a Softgoal element.
- 5.5.11 Guideline (Beginner,Concept) Avoid introducing ad hoc or improvised link types. If you must, define their syntax and semantics as extensions to i*.
- 5.5.12 Guideline (Beginner,Concept) Use the OR Contribution Links to indicate alternatives for satisficing a Softgoal.
- 5.5.13 Guideline (Beginner,Concept) Don’t use Correlation or Contribution Links between actors.
- 5.5.14 Guideline (Beginner,Concept) Don’t use Correlation or Contribution Links from a Task to a Task.
- 5.6 Leaf Elements
- 5.7 Strategic Rationale Example Model: Buyer Drive E-Commerce from Yu01
- 5.8 Operationalizations and Refinement of Goals and Softgoals
- 5.8.1 Guideline (Beginner,Concept) Use Contribution Links to refine a broad softgoal or non-functional requirement (NFR) into smaller components.
- 5.8.2 Guideline (Beginner,Naming) To facilitate systematic refinement, use Type and Topic naming convention for Softgoals.
- 5.8.3 Guideline (Beginner,Naming) Where Type and Topic structure is used, be consistent in each refinement step to refine either by Type or by Topic.
- 5.1 Boundary/Actor Boundary
- 6 Naming, Icons, and Colors
- 6.1 Guideline (Beginner,Naming) Avoid including non standard elements or notations in the model.
- 6.2 Guideline (Beginner,Naming) Be consistent when using colors in the models.
- 6.3 Guideline (Beginner,Naming) Use a suitable font size for the element name.
- 6.4 Guideline (Beginner,Naming) Select concise but informative phrases to name the elements.
- 6.5 Guideline (Beginner,Layout) Don’t extend the text of the name of the element beyond the element’s boarder.
- 6.6 Guideline (Beginner,Naming) Do not use Verbs in the names of Actors, Agents and Positions.
- 6.7 Guideline (Beginner,Naming) Use clear names without ambiguous and unknown abbreviations or acronyms.
- 7 Scaling
- 8 Level of Complexity
- 9 Model Analysis
- 9.1 Useful Analysis Concepts
- 9.1.1 Ability
- 9.1.2 Workability
- 9.1.3 Viability
- 9.1.4 Believability
- 9.1.5 Concept Use
- 9.2 Model Evaluation
- 9.2.1 Guideline (Intermediate, Evaluation) Employ a systematic evaluation procedure
- 9.2.2 Evaluation Step 1: Decide on an Analysis Question
- 9.2.3 Evaluation Step 2: Set Initial Labels Based on Question
- 9.2.4 Evaluation Step 3: Propagate Label Values
- 9.2.5 Evaluation 4: Interpret the Results
- 9.2.6 Iteration: Repeat Steps 1 to 4 for each Analysis Question - Modify the Model if Needed
- 9.1 Useful Analysis Concepts
- 10 Methodology
- 10.1 Early and Late Requirements
- 10.1.1 Guideline (Beginner,Methodology) Model the As-Is state of the knowledge domain and system without the presence of the new system To-Be introduced.
- 10.1.2 Guideline (Beginner,Methodology) Model the To-Be state of the knowledge domain under analysis including the new To-Be system.
- 10.1.3 Guideline (Beginner,Methodology) Start the modeling with the SD model to capture the stakeholders and their associated dependencies and interactions.
- 10.1.4 Guideline (Beginner,Methodology) Employ SR models to expand on the SD models and add the intentionality and rational dimension to the analysis.
- 10.2 Progressive Elaboration
- 10.3 Guideline (Beginner,Methodology and Layout) Use the leaf-level tasks as the system requirements, not the high level Goals and Softgoals.
- 10.1 Early and Late Requirements
- 11 Acknowledgments
- 12 References
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