Here's my review. Comments are appreciated...
The Design Space of Ubiquitous Mobile Input
[Ballagas et al., 2008] presents a design space of mobile input techniques with five dimensions: graphical subtask (position, orient and select), dimensionality, relative vs absolute movement, interaction style (direct vs indirect) and feedback (continuous vs discrete).
Ballagas uses the taxonomy of desktop input devices, defined in [Foley et al., 1984], centered around the graphical subtasks of Position, Orient, Select, Path, Quantify and Text Entry to structure the analysis of the mobile input devices:
- The 'Position' subtask enables the user to specify a position in application coordinates. Position may be defined in one, two or three dimensions.
- The 'Orient' subtask involves specifying the direction of an object instead of its position.
- The 'Select' subtask represents a choice the user makes from a set of alternatives.
- In the 'Path' subtask the user specifies a series of positions and orientations over time.
- In the 'Quantify' subtask the user specifies a numeric value.
- In the 'Text Entry' subtask the user specifies a text value.
He also uses the 'feedback' and 'interaction style' input characteristics used by Foley as two of the dimensions in the final design space. Feedback may be 'continuous' if the user gets continuously informed of the task progress of 'discrete' if the user get informed only after the action is complete. The interaction style may be 'direct' when actions are physically coupled with the entity being manipulated or 'indirect' if some scaling or abstraction between input actions and the result of those action is needed.
Dimensionality refers to the number of dimensions supported by the interaction device (one, two, or three dimensions) and it can refer to spatial or rotational dimensions.
The 'relative vs absolute' dimension refers to how input is specified: relative input is given as an amount of change from the previous input; absolute input is given independently of any input history.
Ballagas analyzes a series of input techniques for each of the subtasks and plots them against the five dimensions building a design space for mobile input devices. This design space is meant to help designers to better choose an input mechanism to use in a given application. Also, the review of techniques presented gives some insight to the key design factors of each technique.
[Ballagas et al., 2008] Ballagas, R., Rohs, M., Sheridan, J. G., and Borchers, J. (2008). The design space of ubiquitous mobile input. In Lumsden, J., editor, Handbook of Research on User Interface Design and Evaluation for Mobile Technology, volume 1, chapter 24. IGI Global.
[Foley et al., 1984] Foley, J. D., Wallace, V. L., and Chan, P. (1984). The human factors of computer graphics interaction techniques. IEEE Computer Graphics and Applications, 4(11):13-48.
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