exercises  -  17. models of the system

EXERCISE 17.7

Sections 17.2.1 and 17.2.2 give two reasons for using formal methods in HCI: communication and analysis. These are focused on the sort of mathematical models found in chapter 17. However, there are other sort of 'formal' modelling in HCI: dialog notations are formal models of the syntax of the human­computer conversation, hierarchical task analysis is a formalisation of the task structure, some cognitive models are effectively formal models of the user's mind.

• Are communication and analysis reasons for using these other sorts of formalism?
• Can you think of other reasons why you would or would not use formalisms?
• Try to use these pros and cons to formulate issues in the choice of appropriate forms of formal model and analysis.