=Paper=
{{Paper
|id=Vol-254/paper-11
|storemode=property
|title=Interstitial Interfaces for Mobile Media
|pdfUrl=https://ceur-ws.org/Vol-254/paper11.pdf
|volume=Vol-254
|dblpUrl=https://dblp.org/rec/conf/pervasive/WickramasuriyaVN07
}}
==Interstitial Interfaces for Mobile Media==
https://ceur-ws.org/Vol-254/paper11.pdf
Interstitial Interfaces for Mobile Media
J. Wickramasuriya, V. Vasudevan and N. Narasimhan
Pervasive Platforms & Architectures Lab
Applications Research, Motorola Labs
1295 E. Algonquin Road, Schaumburg IL 60196
{jehan, venu.vasudevan, nitya}@motorola.com
ABSTRACT waiting for friends at a restaurant). Therefore, in this paper
Mobile devices make ideal personal ambient information we explore the key design issues that need to be addressed
systems given their ubiquitous adoption by users and their when architecting mobile ambient information systems for
rich context knowledge of users’ activity. However, we interstitial consumption of content. These include:
believe that unlike traditional systems, the mobile device • Information Selection – What kinds of information will
acts more as an interstitial information appliance, allowing be viewed as “value-add” by a mobile user and will lend
users to consume relevant information at-a-glance primarily themselves to interstitial consumption?
during the interstices between other activities. In this paper,
• Rendering Abstractions – What primary visualizations of
we motivate a discussion on how such usage behavior can
ambient interfaces will enable mobile users to balance
impact the design, display and delivery characteristics of
breadth of awareness with cognitive overload?
ambient information systems for mobile devices. We focus
not just on design issues (information selection, rendering • Evaluation Metrics – How do we measure the impact of
abstractions, impact evaluation) but also on the ecosystem such systems on end users? Can we qualitatively identify
concerns (provisioning costs, business models) that often factors that enhance (or disrupt) interstitial consumption?
prove critical to developing commercially-viable solutions. • Pragmatic Concerns – What service provisioning costs
and business models should we factor in, when creating
Keywords
‘commercial’ mobile ambient information appliances?
Ambient interfaces, mobile media, information awareness,
presence, context-awareness Many of our insights on these issues, and on potential
solutions to them, have been influenced by our experiences
INTRODUCTION with SCREEN3 [2], the ‘zero-click’ ambient interface
Ambient information systems help users stay connected to currently deployed on over two million handsets worldwide.
relevant but non-critical information in a non-intrusive way.
Mobile handsets make ideal personal ambient information RELATED WORK ON MOBILE AMBIENT DISPLAYS
appliances due to both their penetration among the global Research on ambient information systems has yielded a rich
consumer population and their rich contextual knowledge. and diverse variety of design approaches. These have been
The always-on, always-connected nature of handsets could covered exhaustively in papers such as [3][13] but can be
conceivably enable “what’s happening” style interfaces [1], coarsely segmented into specialized ambient displays (e.g.,
allowing users to remain up-to-date with their community Ambient Orb, Water Lamp [4]) which are aesthetically-
information anytime, anywhere. However, this potential is pleasing representations of small (and often single) datasets,
underutilized because a number of mobile interfaces offer a and information monitors that tend to unify multiple data
‘miniaturized browsing’ experience that is at odds with sources under a single awareness interface.
users’ desire for a ‘passive awareness’ interface – one that The latter can be segmented further into distributed display
exposes them to a breadth of relevant information but with architectures (e.g., Eye-Q [5]) where a primary display is
minimal interruption. By definition, browsing requires a augmented with a secondary display that interoperates
degree of user attentiveness (in querying, navigating and seamlessly with the primary, and primary display adaptors
selecting content) that lends itself better to a lean-forward (e.g., Sideshow[6]) that repurpose an existing primary
tethered PC experience than to a lean-back mobile one. interface for ambient information delivery. Under this
What then constitutes an effective ambient interface for the categorization, we view mobile devices more as information
mobile device? In our experience, users expect mobile monitors than as specialized ambient displays. Both the
phones to act as an interstitial information appliance – one monitor-based approaches are viable for mobile phones.
that allows them to grab an ‘information bite’ quickly and However, the distributed display architecture approach pre-
opportunistically during the interstices between other supposes the development and existence of an ‘accessory’
activities (e.g., while standing in the airport security line or ecosystem – this is likely to happen only over much longer
Copyright is held by the author/owner(s).
Pervasive '07 Workshop: W9 - Ambient Information Systems,
May 13, 2007; Toronto, Ontario, Canada
This position paper is not an official publication of Pervasive '07.
time horizons. By contrast, the primary adaptor solution can interstitial consumption. From the mobile perspective, the
co-exist easily with currently-supported mobile hardware. amount of information conveyed can be characterized by
Our classification of mobile phones as information monitors factors like the channel bandwidth (number of concurrent
gains further credibility in the light of recent user studies by information channels supported as ambient interfaces), the
Schmidt [9] that show how screensaver-like visualizations information density (ratio of information value to message
of ‘communication meta-information’ can help users track size) and hysteresis (rate of decay in perceived value of
the strength (or lack thereof) of their social ties. This meta- item over time).
information includes data on frequency of communications, In our experience, effective mobile experiences may be able
identity of the initiator, last in-person encounter (based on to support channel bandwidths of 3-5 channels*, with
proximity) and other contextual cues. Their work also content characterized by a high information density coupled
explores design cases which attempt to tie various technical with a low hysteresis (1-5 hours). However, future work
capabilities of the device (e.g. GPS, Wi-Fi, accelerometer) may discover ways of conveying more information in a
to what can be presented via the ambient display The focus glanceable manner. High information density (e.g., a sports
is on utilization of the mobile device as a sensor which score, or a stock quote that conveys high-value information
inherently provides rich, personalized information that can in just a few bytes) is especially important for mobile
be used both to drive content on the ambient information devices, given the relatively high cost of cellular bandwidth
display and to influence how it is presented to the user. and the limited cognitive bandwidth display real-estate
Many desktop-resident ambient information systems (e.g., available to users. Emphasis on ‘hysteresis’ is also a
“What’s Happening” [1], Apple Dashboard [7], and Yahoo! function of the high cost of data delivery to the handset. To
Konfabulator [8]) have also pointed out the desirability of a conserve valuable bandwidth and battery, mobile
passive click-free (lean-back) user experience. These zero- information appliances often resort to ‘cache-and-render’
click experiences become particularly important for mobile models that leverage periodic bulk transfers to the mobile
interfaces given device input constraints – industry reports device (in lieu of expensive incremental or continual real-
show that the proportion of engaged mobile users decreases time information updates).
in almost geometric progression with the effective “click- Notification Level
distance” of the relevant item from the main screen. Notification levels reflect the degree of interruption that is
Finally, we note commercially-available technologies such acceptable to users. It is typically dependent on the user’s
as Widsets (Java-based widgets) [10] and the SCREEN3 (0- interest in his current task – which varies from inattention to
click idle screen interface) [2] provide ideal vehicles for divided attention to more focused attention. Accordingly,
mobile interstitial consumption experiences. All of these researchers [12] have identified five notification levels for
factors collectively influenced our thinking and guided our peripheral displays namely ignore, change blind, make
exploration of basic design principles for mobile ambient aware, interrupt and demand attention ordered by their
information systems. increasing intrusion into user consciousness. However,
Pousman and Stasko observe that ambience is best-served
DESIGN PRINCIPLES by change-blind and make-aware style notifications only.
We begin by defining the dimensions of an effective mobile
interstitial display. We borrow heavily from Pousman and We agree with this philosophy. In general, high levels of
Stasko’s taxonomy of ambient information systems [3] interruption are especially heinous in mobile environments
which identifies four dimensions of design – information where device constraints and the likelihood of users being
capacity, notification level, representational fidelity and otherwise engaged, combine to make such alerts annoying –
aesthetic emphasis. In particular, we refined the definition leading to users questioning the utility of such interfaces,
of ‘ambient’ and its dimensions to better characterize the and potentially tuning out all notifications subsequently.
mobile domain and to introduce additional elements that are However, interstitial consumption may require switching
unique to the mobile ecosystem. between different notification levels based on known or
predicted level of user attention. By default, ‘idle screen’
Information Capacity behavior should be seen as user inattention – less intrusive
This denotes the nature and amount of information that can alerts suffice. However, a user action (e.g., click through)
be effectively depicted on an ambient display. The passive indicative of user engagement in the content may be
nature of these systems and the low interruption-tolerance perceived as divided or focused attention – more intrusive
of mobile users suggest that interstitial information systems alerts (e.g., to arrival of fresh content) may then be
are best used to convey non-critical, delay-tolerant content acceptable within that interstitial consumption ‘session’.
for casual consumption. Deployment experience and user
studies indicate that environmental information (e.g., local
*
weather), general news (e.g., sports, entertainment) and This is not an empirical figure, but a relative measure based on our
updates from the user’s primary social group (e.g., music evaluation of a specific implementation of a mobile ambient interface
and motion presence) are viewed as being appropriate for (SCREEN3). In particular, this takes into account screen real estate
limitations of mobile devices and cognitive user experience.
Representational Fidelity information visualization. Different classes of tickers can be
The taxonomy for representational fidelity [3] focuses on envisioned – continuous scrolling (steady rate), discrete
the diversity of symbols and notation used in depicting the scrolling (employing scrollpausescroll cycles) and
information on the ambient display. High bit and bandwidth serial presentation (no scrolling, just item replacement).
costs restrict the symbolic flexibility of mobile interstitials Our initial thoughts favor the use of discrete scrolling since
to basic text and minimalist symbols. However, synthetic this allows users to consume sufficient information without
media approaches (e.g., avatars) could leverage the fact that additional effort on their part – also giving them sufficient
such devices are rich in graphics capability even if network time to react to information by clicking-through for details.
bits remain expensive. Limited representational fidelity
Fairness
enhances glanceability since the user does not have to
We augment Pousman and Stasko’s taxonomy with the
master a complicated set of notations in order to interact
dimension of fairness, as a way for passive interfaces to
with the information system.
support a larger information capacity without active user
A second aspect of representational fidelity (from a mobile navigation. It’s quite common in channel-oriented mobile
perspective) focuses on nesting – i.e., allowing the user to systems (e.g. SCREEN3 below) for the number of channels
“snack” superficially on a number of content channels but to exceed the display capacity† of the device, and for the
then enabling him to drill down further to obtain additional number of items per channel to exceed what can be shown
details on items of specific interest. to the user at one time. The definition of fairness for
Aesthetic Emphasis ambient information systems parallels its usage in
Aesthetics is essentially viewed as a subjective discussion distributed systems – namely that every ‘channelized’
[3] where focus can vary from the innovativeness behind information item will have fair access to “face-time” with
physical artifacts that blend into the user environment to the the user – even if the user does not actively navigate to it
ability to use other means to communicate the information directly. The carousel model adopted by SCREEN3 is a
effectively. From the mobile device perspective, we rate good example of a fair ambient information system with a
aesthetics in terms of the success of the user interface in non-weighted, round-robin selection scheme. However, one
maximizing the user’s “ambient bandwidth” – i.e., how well can imagine a number of alternative ambient interfaces that
does the interstitial ambient interface adapt to the user’s support fairness. We note that fairness becomes particularly
current need for information such that the user is able to important in commercial systems where many third-party
tradeoff breadth of information with depth of detail at any providers of such ambient content have a vested interest in
given time. Given resource constraints, an aesthetically- having their content seen by the user at some point. This is
pleasing interface must avoid clutter and yet be relevant. different from the case where users elected to receive
specific content of interest – i.e., the user knows the content
We see different ‘modes’ of ambience (rendering exists and can navigate to it if desired, while in the earlier
abstractions) in existence today that translate to mobile case users remained unaware of its existence unless they
devices with different levels of success. ‘stumbled’ upon it by accident.
• Carousel – interface limited to a small segment of
Privacy Concerns
available real estate. Is ideal if sequential access to
The mobile phone is a deeply personal device, thus
information can be tolerated. Is good for low item
naturally privacy concerns arise when talking about a
counts (allowing users to scroll through items quickly
medium on which to display contextualized and possibly
to locate specific content) but can be adapted for higher
personalized information that may be viewable by others.
counts with intelligent design. E.g., SCREEN3 [2].
As much as ambient visualization is a central means for
• Widgets – interface is ideal for scattered usage over user awareness, the fact that in certain situations, it may be
larger display real estate. [7, 8,10] Is ideal if parallel publicly viewable raises concerns about how the
access to information sources is desirable. Is good for information needs to be presented. A lot of this concern is
moderate item counts, though user action may be with protecting the user from undesirable situations [13].
desired in order to “select” from large populations of Ambient interfaces (particularly multimodal ones), are not
available widgets for display at a given time. as familiar in terms design and hardware ergonomics
• Clouds – can be rendered within a carousel or as a compared to the PC for example. Therefore, it makes sense
widget. These abstractions adapt to real estate available to adopt an approach where any personal information is
but focus on displaying aggregate data rather than tagged as sensitive (e.g. communication meta-information
details [11]. Such “heat maps” are ideal for huge item such as call lists, contacts etc.) and filtered out when
counts where user interest is likely to be in the overall
trend rather than in individual samples. †
Here, display capacity represents the ‘viewing window’ provided to the
Based on our experiences with SCREEN3’s carousel mode, user within the available display real estate. It could equal the physical
we see value to a comparative study of such ‘ticker-style’ display size (for full-screen ambient interfaces) or could be some subset
interfaces that use wipe-based transitions for ambient of it that is specifically allocated for ambient usage.
displaying ambient information. It may also be possible to zero-click consumption experience. The server caches
achieve finer-grained access control by utilizing more client state in order to decide what updates need to be
dynamic, contextually-triggered filtering. There is certainly delivered to the mobile device. However, the content being
a lot of scope for future work in this area, which should be displayed remains still fairly static in terms of both its
considered an integral part of the design process rather than applicability to the user (i.e., it may be a channel that the
an afterthought. user subscribed to in the past, but hasn’t actively in recent
Figure 1: SCREEN3 user experience times) and its visualization on the device.
EFFICACY MEASURES FOR INTERSTITIAL SYSTEMS
User interactions convert “ambience” into “intent”. This
tipping point is of value from a business perspective, as it
bridges content and commerce. Where passive viewing a
news item represents casual interest in something, actively
interacting with it might indicate sufficient interest in the
topic or item to merchandise related goods and services.
Identifying user interests can also provide personalization
of ambient information. This improves not only system
efficiency (ability to prioritize fetching and caching of
content that is likely to be of more interest to this user) but
THE SCREEN3 CONCEPT
Our exploration of mobile ambient interfaces was motivated also the hit-rate (user click-through) for interstitial
primarily by our experiences with using the SCREEN3 consumption of related content.
technology [2] developed at Motorola for mobile handsets. The latter is particularly important on mobile devices.
SCREEN3 targets the idle screen of mobile devices as the Display constraints limit the information capacity, allowing
ideal delivery point for news, weather, sports, entertainment only a few items to become visible in any limited time
and other updates. The SCREEN3 client (on the handset) window. Further, interstitial consumption patterns imply
supports multiple channels of information (e.g., one for that the face-time afforded to ambient information systems
sports, another for community updates), and multiple items is usually limited to short ‘windows of opportunity’ in
per channel. A SCREEN3 media gateway (server) manages between other user tasks. Thus, items must now compete
different content feeds, allowing the client to obtain the for the user’s attention within a given opportunity. Item
freshest information for each feed (channel) of interest selection becomes key to either holding the users’ interest
(pull-based, with the capability of WAP push). (thus providing opportunities for other items to be shown)
The SCREEN3 model’s emphasis has been on providing or losing it (thus ensuring that he or she remains unaware of
users with a zero-click, lean-back experience for lazy the existence of items that are relevant and interesting).
content consumption – with the ability to transition to a So how can we measure the impact of ambient information
more lean-forward, interactive experience as desired. systems? We propose various measures that reflect different
degrees of user engagement and for different rendering
These different degrees of user engagement are supported
abstractions (e.g., carousel-based, widget-based)
by a “bite–snack–meal” approach to information delivery as
shown in the figure. The “bite” contains headline-quality • Attention Measures. Identifies the minimal level of
information for content items, enabling users to consume it engagement with ambient information. E.g., time spent by
at a glance (passive awareness). For items of interest, users user in scrolling through channels, or time for which an
can easily transition to a lean-forward (more interactive) item was in focus with user present at device. While the
experience by clicking through to receive a “snack” – notion of an attention measure could apply equally well
typically a cached extended summary for the headline to PCs and TVs, the fact that the phone is a personal
article. For more information, users can then click through device on which content consumption is a deliberate
the snack to request a complete “meal” – typically a link to decision, is likely to provide “clean”, high quality
a network repository containing the complete article with attention data. As shared devices, both the PC and TV
richer media attachments that the user can browse online or suffer from the “who’s watching” drawback (according to
download for consumption. an industry statistic, over 50% of the time, the TV is on
with nobody watching). Simple context enablers can
SCREEN3 currently adopts a carousel model for displaying
disambiguate mobile-in-the-pocket and mobile-to-one’s-
information bites – the carousel can be navigated manually
ear situations, and allow more accurate measurements of
(to enable scrolling through the channels, or through items
content viewing on the handset.
within a channel) but is typically animated, automatically
scrolling through channels and items in sequence for a true • Action Measures. Identifies a higher level of user
engagement related to a specific item or channel,
particularly since the user is potentially aware of possible
delays in fulfillment such as for network downloads. E.g., 2. Motorola introduces SCREEN3: “Zero Click” access to
user click-through (bitesnackmeal) or hidereveal News, Sports, Entertainment and more. November 2005.
transitions for specific widgets [7] [8] [9]. http://www.motorola.com/mediacenter/news/detail.jsp?
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QUESTION FOR DISCUSSION 10. Nokia launches WidSets to boost Web 2.0 services on
This discussion was motivated by a single but multi-faceted mobile handsets. Oct.2006.
question: What differentiates the design of a mobile http://www.forbes.com/technology/feeds/afx/2006/10/03
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Ratttenbury, T. 2004. A toolkit for managing user
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ACKNOWLEDGMENTS
13. Gross, T. Ambient Interfaces: Design Challenges and
We thank the various members of Motorola Labs and the
Recommendations. In Proceedings of the 10th
SCREEN3 team who helped us gain a better understanding
International Conference on Human-Computer
of the operation and utility of this interface on the handset.
Interaction - HCII 2003 (June 22-27, Crete, Greece).
Lawrence Erlbaum, Hillsdale, NJ, 2003. pp. 68-72.
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