Automotive User Interfaces and Interactive Vehicular Applications

the user can use her preferred expression next time instead
of using the default expression or give the input manually.
[8] states that voice operation of in-vehicle information systems
(IVIS) is desirable from the point of view of safety
and acceptance. The study reported in this paper supports
that, but we recommend a multimodal interface. Although
the drivers, when asked, preferred to interact using speech,
a manual alternative is useful when a speech interface is not
wanted. For example, if the environment is noisy, the driver
does not want to disturb the passengers or the speech recognizer
does not seem to understand what the driver is saying.
When it is not possible or appropriate to use speech, a multimodal
interface gives the driver an opportunity to choose.
7. SUMMARY AND CONCLUSIONS
To sum up:
• Regarding task performance, SUI gets the lowest scores
whereas MM and GUI get roughly similar scores
• Regarding driving ability, GUI gets the lowest score,
whereas MM and SUI get roughly similar scores
• Regarding task completion time, GUI is the fastest
whereas MM and SUI get roughly similar scores
The MM condition gives the same task performance as GUI,
the same driving ability as VUI, and beats both with respect
to driving ability. Future research includes improving the
MM system to decrease task completion time, and investigating
whether (and how) this affects driving ability.
8. FUTURE RESEARCH
Since the study reported here was conducted, the multimodal
Dico application has been extended with a speech
cursor [4]. The speech cursor enables the user to use spoken
interaction in combination with haptic input to access
all functionality (including browsing long lists) without ever
having to look at the screen. It requires a haptic manu
navigation device, such as a mouse (trackball, touch pad,
TrackPoint T M ) with buttons, pointers and drivers, keyboard
with arrow keys or jog dial/shuttle wheel. A typical invehicle
menu navigation device consists of three or four buttons
(UP, DOWN, OK and possibly also BACK). Every time
a new item gets focus, the system reads out a ”voice icon”
- a spoken representation of the item. This representation
can be textual, intended to be realised using a TTS, or in
the form of audio data, to be played directly. Every time a
new element gets focus, all any ongoing voice output is interrupted
by the ”voice icon” for the element in focus. This
means that you can speed up the interaction by browsing to
a new element before the system has read out the previous
one. In future work, we plan to perform a study comparing
a multimodal system with speech cursor to voice-only, GUIonly,
and multimodal interaction without speech cursor.
Additional future research includes implementation of theories
of interruption and resumption strategies. In-vehicle
dialogue involves multitasking. The driver must be able to
switch between tasks such as, for example, adding songs to a
playlist while getting help to find the way from a navigation
system. To avoid increasing the cognitive load of the driver,
the system needs to know when it is appropriate to interrupt
the current dialogue to give time-critical information
[1]. When resuming the interrupted dialogue, the system
should resume when the driver is prepared to do so and in
a way that does not increase the cognitive load [7].
9. ACKNOWLEDGEMENTS
The study presented here was carried out within DICO, a
joint project between Volvo Technology, Volvo Car Corporation,
Gothenburg University, TeliaSonera and Veridict with
funding from the Swedish Governmental Agency for Innovation
Systems, VINNOVA (project P28536-1). The authors
wish to thank Alex Berman and Fredrik Kronlid at Talkamatic
AB for helping out with the implementation.
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