Why Seek Ubiquitous Event-Filtration Control at the
Multi-user Desktop?
Rameshsharma Ramloll
Lancaster University
Lancaster, LA1 4YR, UK.
Phone: +44 1524 59-3041
Fax: +44 01524 593608
Email:ramloll@comp.lancs.ac.uk
Type of contribution: Research
ABSTRACT
Ideally, a multi-user desktop environment must cater adequately for dynamic and
possibly unanticipated awareness needs of each participant [6]. Any strategy to fulfil these
needs appropriately without overloading the participant with awareness-information presupposes the ability of the multi-user environment to be continuously informed of her
awareness requirements. This provides the awareness engine [9, 17, 18] of the multi-user
environment with the necessary guidelines to synchronise evolving awareness requirements
with the presentation of awareness-information on individual desktops. Two ways in which
this can be achieved are considered. One involves supplying the participant with a number of
tailoring primitives which can be selected to enable specific event-filtrations. The other
involves endowing the multi-user system with the ability (1) to track continuously the
participant’s behaviour at the interface, such as her direct manipulations of interface
elements, (2) to deduce her awareness needs and (3) to automatically configure or tune
appropriately the awareness engine of the multi-user system. In this short paper, we contrast
between these two approaches as follows. The first one involves explicit tailoring for
awareness-information as the tailoring operations are distinguishable and separate from
actual task operations. The second one involves ubiquitous tailoring for awarenessinformation since the tailoring operations are indistinguishable from and inherent in actual
task operations.
KEYWORDS
Multi-user desktop system, multimedia browsing, common information space, awareness
INTRODUCTION
In general, we contrast between two different types of operations normally carried out
at typical user interfaces as follows. Some operations are directly related to some task to be
completed, while others are used for tailoring purposes. The following is an example where
task operations and tailoring operations can be clearly distinguished. In a single user
application such as a word processor, an end user may perform tailoring operations either to
personalise the GUI, e.g. by changing positions of buttons through drag and drop, or to
enable deeper customisations, e.g. by creating macros. In the same example application,
instances of operations that are directly related to actual tasks are those such as typing,
moving, formatting or deleting text. Earlier, Bentley and Dourish have recognised and
explained the abstraction gulf that can potentially exist between task operations and tailoring
operations [3]. In the chosen application, the level of abstraction of the tailoring operation for
changing the position of buttons is very close to the level of abstraction of the task
operations. However, this is not the case for the deeper customisations through macros. We
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argue that in order to make tailoring operations more attractive to end users who are not
computer specialists, it is perhaps necessary to ensure that the abstraction gulf between
tailoring operations and task operations is minimised. In this paper, we propose that there is
scope for avoiding this abstraction gulf problem all together when considering a specific type
of tailoring namely that involved in the filtration of awareness-information in multi-user
desktops. We attempt to achieve this goal by automating the said tailoring process so that it
no longer has to be considered explicitly by the end-user thereby making it ubiquitous. We
now give a brief overview of popular event filtration strategies before introducing our
approach.
Current Event-Filtration Control Approaches
Collaborative systems, such as multi-user desktops, need to provide some means for
users to be aware of peer activities. Common approaches involve broadcasting events
generated as a result of a particular user’s actions at the interface to others. Rather than
flooding users with information about all activities occurring in the shared environment,
filtration techniques allow each user to be exposed to relevant awareness information. Such
techniques are often based on user configurable agents. We argue that the configuration of
this agent may complicate work-practices by substituting the information overload or scarcity
problem with an explicit agent configuration one. Having user defined interest profiles or
interest group subscriptions as proposed by some researchers [10,12], or any other kind of
overt explicit run time or pre-run time user configuration, require disruptive user
interventions. These are likely to increase proportionally with the dynamic nature of work
[19]. In addition, even if non-computer specialists can tailor event-filtration-control through
the selection of appropriately chosen and easy to learn situation metaphors [5], it is a difficult
task for the system designer to produce a complete list expressing the wide diversity of
collaborative patterns. This is partly because as Bentley and Dourish points out, the main
route towards more effective collaborative systems does not necessarily involve the creation
of ever more intricate and more detailed representations or models of group work [3].
Approaches based on such beliefs are not only likely to impose a steep learning curve on
prospective users of the collaborative system but may also make the real time
synchronisation of awareness-information presentations and awareness-information
requirements difficult.
Our Approach: Desktop landscapes as descriptive languages for task needs
and awareness needs
Our event filtration strategy is based on the view that a desktop landscape, just like a
real world desktop landscape, is a description of the task needs, workpractices and states of
progress of users [2, 11, 13]. We claim that, given the right choice of metaphors, event
filtration mechanisms and coupling strategies between individual desktop interfaces, the
desktop landscape can in addition, be turned into a language that can be used to express
individual awareness needs accurately and easily. Once the user has expressed his particular
need for awareness about peer activities on given objects by naturally constructing such a
desktop landscape, the system has to interpret the latter and respond by providing the user
with the appropriate awareness information at suitable emphasis levels. Under this model, the
resulting tight coupling between views and awareness needs may play an important role in
achieving real-time synchronisation of awareness-engine configurations and user needs for
awareness information. This factor is essential if unanticipated and dynamic complex
collaborative patterns are to be supported by the multi-user desktop. In addition, the fact that
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the level of abstraction of tailoring operations is at par with that of task operations may make
such a multi-user interface attractive to end users who are not computer specialists.
ACHIEVING UBIQUITOUS FILTRATION OF AWARENESS INFORMATION
We now describe broadly our solution space for achieving ubiquitous filtration of
awareness information at the multi-user desktop. Our approach is being implemented in a
multi-user desktop system, Moksha, which has been described in further details
elsewhere[15].
1. Firstly, we design a new Common Information Space (CIS) [1] visualisation model with
inherent support for dynamic concurrent logical views. This is needed to allow users to
construct their own logical views of the CIS and to naturally structure their workspace
according to the logic of their work practice, just like they would have in a single user
environment.
2. Secondly, we introduce a new desktop metaphor that will provide a smooth evolutionary
path from the current popular one. This will play an important role in making the
concepts needed to interact with our CIS object visualisation model accessible to the
general user. This metaphor will not only allow the end user to construct desktop
landscapes according to task needs but also according to awareness needs.
3. Thirdly, we develop services that will manage the propagation and filtration of events
between logical views and determine how these events trigger meaningful informative
behaviours in CIS object representations within each logical view. These services are of
crucial importance to our system as they are responsible for making each desktop aware
of each other.
4. Fourthly, we investigate new techniques for representing and browsing activities of
others at the multi-user desktop. Interface elements representing files, applications or
devices are not only handles to objects in our multi-user environment but also places for
the representations of activities performed on them. Our aim is to exploit as many media
as possible so as to maximise the bandwidth for information transfer from the virtual
environment to the end-user. Currently, our experiments involve only the visual and
auditory media.
WORKS IN PROGRESS
The following describes the ongoing implementation of our multi-user desktop
system, Moksha. One main component of our design is its multi-user file visualisation
system which has been described elsewhere [16]. Our aim when developing this visualisation
system is to make available to the end user concurrent logical views to the CIS while
minimising explicit user intervention involving the manual creation and organisation of
aliases. In our case, a logical view typically consists of representations of shareable/nonshareable files, devices and applications grouped in classification constructs e.g. folders and
rooms. We have striven to avoid right from the beginning any direct interdependence
between the actual location of information on physical storage and its final representation to
the end user. Ensuring a clear separation between logical views and the physical view of data
constituting the information space allows each view to have its own structure instead of being
based on a common one as is the case in traditional multi-user file system visualisations. It is
important to note that our approach does not prevent a common structure to be simulated in
cases where such an environment is desirable.
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We are currently investigating the use of animated and annotated icons with
associated localised sounds describing the activities of others on objects they represent at the
multi-user desktop. This approach may be more successful in providing in-context awareness
information rather than having a list of activities-of-others that is continuously updated and
presented to the end user [12]. We aim at achieving ubiquity in tailoring for awareness by
attempting to implement physical laws, as it were, in the desktop interface so that directly
manipulating the interface elements representing the CIS objects allows the end user to
modulate the emphasis of awareness-information presented to them. For example, hiding an
icon in a folder will cause all its associated localised sounds to be muffled. Thus, the
emphasis of information related to it is reduced. Inevitably, the use of localised sounds
associated with each icon gives rise to dense sonic landscapes. We are currently
experimenting with techniques to author and browse such landscapes [14, 15]. The design of
animated, annotated icons with representative localised sounds provides rich grounds for
research [4,7,8]. Our underlying philosophy here is that since physical laws are already
intuitive to end users, directly manipulating an interface consisting of objects behaving
according to physical laws, may be attractive especially to the non-computer specialist who
needs to understand easily the tailoring process for awareness-information. Elsewhere we
describe an example scenario that shows how an end user can use simple desktop operations
such as drag, drop and move to tailor ubiquitously the awareness engine of Moksha [16], our
multi-user desktop.
Figure 1 shows a snapshot of the current Moksha prototype. Each representative icon
on the desktop is ’live’ in the sense that it is always listening to events happening to its
counterparts in peer desktops and sending to others information about events that itself is
being subjected to. Such events are presented both visually and sonically at the surface of the
icon and modulated according to its placement and containment on the desktop. For example,
a rotating red square on the lower left corner of a room icon indicates that the room has been
opened somewhere else by a peer user, a pulsating circle on the lower left corner of a
document indicates that the document is in use. Localised sounds are also used to describe
the activities of others on shared artefacts. This is especially important when the
representative icons are hidden either behind windows or within containers such as rooms
and folders. The localised sounds are rendered relatively to the position of the sound sensor
to allow the user to identify their placement. The sound sensor can be positioned by using a
mouse or an eye-tracker. In the latter case, the user is deemed free to browse the sonic
landscape and to manipulate directly the interface concurrently. Evaluation of this technique
to browse auditory landscapes is ongoing. The room constructs in Moksha are used to
manage the emergence of relevant representative icons in peer desktops. For example, the
creation of an icon representing a CIS object such as a document in a given room causes
representations of the said document to emerge in corresponding rooms on peer desktops.
Folders in Moksha are only used for local groupings and are essentially a purely single user
artefact.
The design of animated and annotated icons is being tackled carefully to avoid
overloading the small area of icons with information. We attempt to deal with privacy issues
by introducing a new construct called Faraday cages. Creating CIS objects in such containers
will prevent information about activities performed on them to be broadcast to their peers.
We cannot deploy and thus fully test the Moksha system as its underlying access control and
persistent data store mechanisms have not been implemented yet.
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Room
Type.wav!!
Documents
Type.wav!
Type.wav!!!
Draw.wav!!!
Folder
Sound Sensor
Author photo
Figure 1 A typical desktop landscape offered by Moksha (the animating icons are star-annotated)
CONCLUSION
In this position paper, we argue that explicit tailoring strategies for the filtration of
awareness information in multi-user desktop systems are problematic. The two main reasons
are as follows. (1) Explicit tailoring strategies imposes a separate tailoring language that has
to be learnt and understood by the end user before it can be used for customisation purposes.
(2) The time and effort needed to express awareness needs successfully using such a tailoring
language may make it difficult to synchronise in real-time evolving awareness-information
requirements and awareness-information presentations. We propose a novel approach for the
tailoring of awareness-information-filtration which is ubiquitous to the user. Once users
become acquainted with our desktop metaphor and the behaviour of its representational
elements, they will create desktop landscapes not only to satisfy the exigencies of tasks but
also according to their awareness needs. A main goal of our design is to ensure that the
awareness engine configuration, which at all times remains hidden from the user, becomes
automatically synchronised in real-time with her awareness needs. This approach will be
evaluated in actual collaborative settings in order to determine its strengths and weaknesses.
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