Biomedical Engineering Reference
In-Depth Information
Intrasystemic relation
Accessibility
Pure accessibility
problems
Universal design
Usability
Universal usability
problems
Pure usability
problems
eSystems
Figure 15.2
The intrasystemic relation between users and eSystems. UX is represented as the user perspective in the intra-
systemic relation of action and feedback with the eSystem (Federici et al. 2005; Federici and Borsci 2010). The
universal design properties that make up the eSystem are obtained by the intersection of the accessibility and the
usability of the eSystem. By following Petrie and Kheir (2007), the universal usability problems represent interac-
tion problems of usability and accessibility that are found by all kinds of users in a bad intrasystemic relation
because of a bad UX (universal design problems). When the problems affect mostly disabled people's interaction,
we may use the term “pure accessibility problems,” when the problems do not pertain to disabled users' inter-
action, we may use the term “pure usability problems.” However, between these two extremes there are many
different degrees of interaction problems that affect the UX of disabled and nondisabled users.
Objective
oriented
Level accessibility and usability
conformance to the rules
System
Evaluation
Intrasystemic relation
User
Subjective
oriented
Problems and satisfaction of the
interaction (accessibility and usability)
measured by the evaluator
observing the users
Figure 15.3
The possible evaluation perspectives during the evaluation of the intrasystemic dialogue between user and
system: the objective-oriented and the subjective-oriented perspectives. The interaction evaluation has to
take into account not only the properties of a single dimension (the accessibility or the usability), but also the
relations that bind the objective part of the interaction to the subjective one (and vice versa). In this context,
accessibility and usability are considered as necessary steps for the evaluation of the intrasystemic relation
between interface and user.
