Touch and Speech: Multimodal Interaction for Elderly Persons - Biomedical Engineering Systems and Technologies - page 368

Fig. 6. The model for system's response and the model for user's response

used to generate corresponding machine-readable state transition automata and inte-
grated into the Generalized Dialogue Manager of MIGSEP.

4.3 The Elderly-Friendly Design Elements in MIGSEP

According to the design guidelines in the previous section, a set of elderly-centered
design elements were implemented in MIGSEP. Specifically, the most essential ele-
ments are listed below:
• Visual perception: simple and clear layout was constructed without overlapping

items; 12-14 sized sans-serif fonts were chosen for all displayed texts. Simple and
high contrast colors without fancy visual effects were used and placed aside; regularly
shaped rectangles and circles were selected, enabling comfortable perception and easy
recognition.
• Auditory perception: both text and acoustic output are provided as system res-

ponses. Styles, vocabulary, structures of the sentences have been intensively revised.
A low-pitched yet vigorous male voice is chosen for the synthesis.
•

Motor functions: regularly shaped, sufficiently sized and well separated interface
elements were designed for easy access. Clicking was decided to be the only action to
avoid otherwise frequently occurring errors caused by decline of motor function.
“Start” was provided as the only way of orientating oneself to avoid confusion.
• Attention/Concentration: fancy irrelevant images or decorations were avoided.

Unified font, colors, sizes of interface elements were used for the entire interface.
Simple animation notifying changes were constructed, giving sufficiently clear yet not
distracting feedback to the user.
•

Memory functionalities: all items are used with relevant keywords. The number of
displayed items is restricted to no more than three, considering the maximum capacity
of short term memory, the accessible size as well as the readable amount of informa-
tion of the interaction items on a table PC. Logically well-structured and sequentially
presented items were intensively revised to assist orientation during interaction. Con-
text sensitive clues are given with selected colors.
• Intellectual ability: consistent layout, colors and interaction styles are used.

Changes on the interface happen only on data level.