Slides for the Formal Methods in HCI unit of my 2013 online course on HCI https://hcibook.com/hcicourse/2013/unit/09-formal * the myth of informality in interaction design * what to model: user, system and world * types of system model * kinds of notations

1. 
formal methods in HCI
Alan Dix
http://alandix.com/academic/topics/formal/
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2. the myth of informality
spiritus mundi
– formality, precision
= reductionism, positivism = BAD
focus (rightly) on
– context, situatedness, contingency
BOTH needed
– the world is rich and complex
– but computers are formal (as is language)
– key is choosing the right abstractions
– and knowing what is left out

3. what to model
users
– cognitive models
– task models
system
– behaviour
– architectural structure
world
– domain models


4. what to model
users
– cognitive models
– task models
system
– behaviour
– architectural structure
world
– domain models


5. types of system model
• dialogue – main modes
• full state definition
• abstract interaction model
specific
system
generic
issues

6. notations
• graphical
– digital watch STNs, Petri Nets, CTT, UML
• textual
– production rules (used in UIMS and cog. models)
– mathematical formulae, process algebras
• plain old sums
– back of the envelope/placemat calculations