1-3 Interaction

Domain of Object - Things that the user is majorly intersted as the purpose of using certain SW
Instruments - A tool to modify DoO. It can either be direct or indirect

• Direct: usage of an instrument mimics the action of physical reality - i.e. resize image using bullets around image selection box
• Indirect: usage of an instrument is far from physical reality - i.e. dialog bod with lists of actions to be selected.

Evaluating Instruments

• Degree of indirection - lower the better
  - Spatial Dimension
  - if an instrument is far from DoO or takes up too much space, it has high spatial dimension
  - Temperal Dimension
  - if an instrument takes longer time to menipulate DoO, it has high temperal dimension
• Degree of integration
  - the ratio between the number of degrees of freedom, DOF, of the instrument and DOF captured by input device (reflects suitability)
  - i.e. mouse majorly has x, y input. so if a property of DoO that is being manipulated by a instrument has more DOF then the input device, the input device and instrument is less suitable
• Degree of compatibility
  - similarity between the physical actions on the instrument and the response of the object
  - i.e. drag and drop has high compatibility, and dialog box with selectable action list has low compatibility