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Slide 1: Social Modelling James Lockerbie Centre for HCI Design Open Day 21st April 2010 Centre for HCI Design
Slide 2: Social Modelling • For our purposes in the context of requirements engineering • Socio-technical systems: Software-based systems that also include physical components, humans and organizations • Modelling goals, rationales, and strategic relationships among social actors for the future system • Explore and identify system requirements, including non-functional requirements e.g. performance, reliability, usability and so on.
Slide 3: Centre for HCI Design The i* (Eye-Star) Goal Modelling Approach From research at the University of Toronto (Eric Yu PhD 1995) Two model types: • SD model USP1: Dependencies –Identify actors –Identify their goals –Identify who they depend on for those goals • SR model –Decompose actors –Translate qualities into functional elements –Demonstrate quality trade offs USP2: Desired qualities “soft goals”
Slide 4: Centre for HCI Design i* Modelling Basics Key modelling semantics – Intentional strategic actor (roles) • Intentional aspects such as objectives, rationale & commitments Actor Passenger Airline – Goal (functional) • Condition or state of the world that can be achieved or not – Task • One particular way of attaining a goal - a detailed description of how to accomplish a goal – Resource • Physical or informational objects in the world. Used by tasks or produced by tasks – Soft goals (non-functional) • Goals that cannot be so sharply defined, such as goals that describe properties or constraints of the system being modelled
Slide 5: Strategic Dependency Modelling Network of dependency relationships among actors Goal Dependency Passenger Ticket purchased Airline – Depender depends upon the dependee to be able to bring about certain state in the world Task Dependency – Depender depends upon dependee to be able to carry out task Resource Dependency – Depender depends upon dependee for the availability of entity Softgoal Dependency – Depender depends upon dependee to perform some task that meets the softgoal or to perform the task in a particular way.
Slide 6: Departure Management System
Slide 7: Knowledge management tool Learning soft goals – get domain experts and end users involved e.g. relevant learning provided, learning planned etc. Independent of “how” Possible technical solutions – get technical partners involved. Need more than just a goal hierarchy, as we need the tasks to give is the “how”
Slide 8: Centre for HCI Design Tool Support REDEPEND (REquirements DEPENDencies) – Centre prototype for developing i* SD and SR models – MS-Visio plug-ins to draw and analyse models MS Visio REDEPEND SD stencil REDEPEND drawing page REDEPEND SR stencil
Slide 9: Centre for HCI Design Model Checking with REDEPEND Model checking – i* models are large, complex and necessitate computational model checking – Check for unrecognised connections, invalid connections and model bottlenecks REDEPEND validation features REDEPEND error tracking
Slide 10: Advertising Microsite example • e.g. Got milk?
Slide 11: Advertising Microsite example • Keep users as long as possible before sending users to product site • Ideal path – – – – – – user arrives at the landing page intrigued and starts exploring. learns how to interact It’s lots of fun. user looses himself – flow through the experience, user is changing attitude towards the brand – comes across advertising messages, learns about several products. • Create a model using i*