A vision - towards ubiquitous peripheral interaction
Internet enabled cell-phones and PDAs with wireless networking
capabilities enable continuous access to information for mobile users.
A PDA can access information from a server, thus (potentially) keeping
users current. However, users cannot be expected to hold their
cell-phones or PDAs in their hands, constantly checking them for new
information or messages. In other words, these devices support a
"pull model" of information access, in which users have to make an
explicit decision to seek information.
In contrast, wearable devices like wrist computers enable peripheral
awareness of information, a "push model". With a wrist computer, for
example, information such as messages, reminders, and news stories
could be constantly streamed to the device and displayed as a
scrolling "ticker". The information is at the periphery of users'
attention, and there is no guarantee that any particular item will be
noticed. However, from time to time a user may glance at his watch and
notice an item of interest. When this occurs, he can follow up on
that item simply by pressing a button on the wrist display. This will
initiate a program to view that item in detail on the user's PDA. The
user then can take out his PDA and interact with the information as
This workshop will explore the theme of multi-device interfaces for
ubiquitous peripheral interaction in depth. It has a number of
specific goals, including identifying requirements for ubiquitous
peripheral awareness devices and considering specific devices that can
meet these requirements, exploring software techniques and
architectures that drive the interaction, and examining designs for
interfaces that divide their functionality across several wearable
devices. We consider each of these goals in some detail.
Goal 1: devices for ubiquitous peripheral awareness: requirements
A wearable peripheral awareness device must be always on, always
accessible (that is, a user must always be able to receive information
from it), and must not demand explicit user attention (that is, it is
accessible without a user explicitly "taking it out to use", as one
must with a PDA or cell-phone). It would be very helpful if some
version of the device already enjoys widespread use (as do
wristwatches, for example). And, since in our vision, this device is
intended to work together with a PDA, it must be networked. We
believe that wireless devices are much more acceptable to users, which
means that the networking should be wireless.
There are various promising devices that meet some or all of these
requirements. One is a computationally augmented wristwatch. There
has been a lot of activity in this area recently, both in commercial
and research contexts. Companies such as Suunto make sophisticated
wrist computers tailored for sports like golf and skiing. Fossil and
onHand make wrist PDAs that runs Palm OS. Swedish researchers
prototyped a simple 'Reminder Bracelet' (CHI 2001) - LEDs were added
to a wrist band, and they were lighted to show several types of
information of varying levels of importance. Most notably, IBM and
Citizen are prototyping a general purpose wrist computer that runs
Another interesting possibility is the use of audio for peripheral
awareness. For example, Sahwney and Schmandt's Nomadic Radio used
small, neck-mounted, directional speakers to deliver audio. Headsets
that are relatively unobtrusive and still allow users to engage in
normal interaction are another possibility;. Grinter & Woodruff (CHI
2002) did a pilot user study that showed some preference for single
ear headsets; ear buds also are worthy of more exploration.
Other wearable devices also are worth investigating, e.g.,
computational jewelry or eyeglass displays.
When it comes to the networking requirements for a multi-device
interface, Bluetooth seems well-suited. It works over short
distances, but the peripheral awareness device and the PDA will be
well within the working range. While Bluetooth is appropriate for
networking the components of the multi-device interface, the PDA will
need to connect a server (more on this below). This will require a
long-distance wireless networking technology such as WIFI or GSM/GPRS.
Another important issue we will explore is how much can be done with
off-the-shelf devices. The IBM/Citizen 'Watchpad' is not yet
available; if it were, it would fulfill most or all the requirements
mentioned above. However, it currently still may be necessary to do
some simple hardware prototyping along the lines of the Reminder
In general, the workshop will address this goal by trying to reach
agreement on appropriate requirements, developing a comprehensive list
of candidate devices, and evaluating the extent to which each
candidate satisfies the requirements.
Goal 2: enabling software techniques and architectures
For any information delivery system, ensuring that information is
relevant to an individual user is a key goal. This is even more
important in our context. Networking may be relatively slow,
unreliable, and expensive. Most of the time, users' attention will not
be focused on their peripheral awareness device, so the system should
be careful not to distract users from their current tasks.
These considerations pose challenges for the information management
software that runs on the server. This software is responsible for
monitoring events in a user's computational environment (e.g., email,
voicemail, calendar), deciding what information to send to a user's
wearable system, prioritizing that information, dealing with user
responses, and learning from those responses so its decisions can
improve over time.
One challenge for the design of this software is to identify the
factors it can use to make these types of decisions. One such factor
is timeliness. New email or voicemail, upcoming appointments, and
changes to web-based information services such as stock tickers or
sports scoreboards are some examples of timely information. For
mobile use, location also is important in determining relevance. GPS
is one technology that enables devices to be location-aware.
Location-aware devices could notify people of nearby stores with items
they need to purchase, or of nearby friends whom they'd like to
A system also should provide users with information that is important.
For a simple example, it should avoid streaming spam email to its
users. Ideally, it should be able to prioritize all the types of
information (messages, reminders, news items, etc.) and use these
priorities to guide its presentation of the information. Initial
priorities may be based on the type of the information: for example,
getting notified that one of your friends is in the same mall or
library as you is likely to be more important than most news stories.
Finally, an effective system will be adaptable. No two users will
have the same notion of importance. A system should learn from user
responses what that particular user considers important. For example,
if a user frequently reads email messages from particular addresses,
messages from these addresses should gradually receive higher
Thus, the key enabling software techniques come from areas such as
information filtering and artificial intelligence, particularly
machine learning. The workshop will explore the range of techniques
that are relevant, discuss lessons to be learned from existing
research prototypes, and identify open problems where new research is
Goal 3: design of multi-device interfaces
There are several challenges here. One is the general problem of
designing for devices with i/o capabilities that are quite different
from, and relatively impoverished compared to desktop user interfaces.
Devices may have very small displays - or, in the case of audio
devices, no displays at all. And their input capabilities may be very
limited, in the case of a wrist computer, or inherently error-prone,
as with a speech interface. Designing an interface for a PDA or
cell-phone is hard; designing for a wristwatch will be even harder.
Another issue is when it is appropriate to 'promote' information
beyond the periphery, that is, when the system should attempt to
notify the user about some information at once. When this is
necessary, a wristwatch computer might be able to flash its display,
vibrate, or even sound a tone. Of course, the decision whether to
seek the user's attention must be guided by the prioritization
techniques mentioned above.
It's also important to consider how users might respond to items on
the peripheral awareness device that catch their attention. One way
would be to support brief "canned" responses. For a message, in
particular, it should be possible to send a response like "OK" or "I
got your message - will reply in detail when I'm back at my desk"
without having to take out one's PDA. One research question worth
exploring is how to define a small set of generally useful canned
responses. Another issue is how to design an interface for a device
with very limited input capabilities (like a wristwatch) that makes it
simple for users to select a response.
Of course, the most interesting and novel interface design challenge
is how to divide functionality across multiple devices. The simplest
case to envision is one where a user notices something on the
peripheral awareness device, gives a single command (e.g., a button
press) to indicate interest, then takes out a PDA to explore the
information in detail. This model assumes that one first uses the
peripheral awareness device alone, then the PDA alone. It also
requires very simple coupling between the two devices. We think this
model is well worth exploring; however, we also will attempt to
identify situations when a more complicated model for combining the
devices is necessary. For example, when a user has his PDA out and is
using it, should information and notifications still be going through
the peripheral awareness device? Or should they now go through the
PDA? This suggests that the division of functionality across the two
devices may have to be dynamic.