Task-driven plasticity refers to as the capability of a user interface to exhibit plasticity driven by the user’s task, i.e. the capability of a user interface to adapt itself to various contexts of use while preserving some predefined usability properties by performing adaptivity based on some task parameters such as complexity, frequency, and criticality. The predefined usability property con-sidered in task-driven plasticity consists of maximizing the observability of user commands in a system-initiated way driven by the ranking of different tasks and sub-tasks. In order to illustrate this concept, we developed UbiDraw, a vectorial hand drawing application that adapts its user interface by displaying, un-displaying, resizing, and relocating tool bars and icons according to the current user’s task, the task frequency, or the user’s preference for some task. This application is built on top of a context watcher and a set of ubiquitous widgets. The context watchers probes the context of use by monitoring how the user is carrying out her current tasks (e.g., task preference, task frequency) whose defi-nitions are given in a run-time task model. The context watcher sends this information to the ubiquitous widgets so as to support task-driven plasticity.

1. 1 HCSE 2008, 2nd Conference on Human-Centred Software
Engineering , Pisa, 25-26 September 2008
Task-Driven Plasticity: One Step
Forward with UbiDraw
Jean Vanderdonckt, Juan Manuel González Calleros
Université catholique de Louvain (UCL)
Louvain School of Management (LSM) - Information Systems Unit (ISYS)
Belgian Laboratory of Computer-Human Interaction (BCHI)
http://www.isys.ucl.ac.be/bchi

2. 2 HCSE 2008, 2nd Conference on Human-Centred Software
Engineering , Pisa, 25-26 September 2008
Outline
• Introduction
• Related Work
• UbiDraw
• Evaluation
• Conclusion

3. 3 HCSE 2008, 2nd Conference on Human-Centred Software
Engineering , Pisa, 25-26 September 2008
Outline
• Introduction
• Related Work
• UbiDraw
• Evaluation
• Conclusion

4. 4 HCSE 2008, 2nd Conference on Human-Centred Software
Engineering , Pisa, 25-26 September 2008
Motivation
•Porting User Interfaces
– Always has posed challenges
• Adaptation to screen sizes
• Introduction of alternative modalities

5. 5 HCSE 2008, 2nd Conference on Human-Centred Software
Engineering , Pisa, 25-26 September 2008
Motivation
• Ubiquitous computing
– The context in not
anymore limited or
known
– The surrounding
world becomes an
interface to virtually
any type of interactive
system

6. 6 HCSE 2008, 2nd Conference on Human-Centred Software
Engineering , Pisa, 25-26 September 2008
Traditional solutions
• Porting UIs has been solved by:
– Techniques that do not affect the initial design
• Simple Porting
• zoom in/out
• Advantages
– consistency between the different versions
• Drawbacks
– Simple porting reduce the available screen real estate
– zooming may induce many operations related to the zoom manipulation

7. 7 HCSE 2008, 2nd Conference on Human-Centred Software
Engineering , Pisa, 25-26 September 2008
Traditional solutions
• Gathering functions that are related
in principle to the same task.
• Related functions can also
presented in collapsible tool bars

8. 8 HCSE 2008, 2nd Conference on Human-Centred Software
Engineering , Pisa, 25-26 September 2008
Traditional solutions
• Plastic User Interfaces
– Concerns the capacity of a multi-context UI to preserve usability properties
across the various contexts of use (User, Platform, Environment)
– Technique that changed the UI design
• Some reconfiguration of the UI is often needed.
– reconfiguration of UI widgets (low level of abstraction)
– Task Level (high level of abstraction)
To investigate to what extent UI can be ”plastified” at a
higher level of concern than the physical one

9. 9 HCSE 2008, 2nd Conference on Human-Centred Software
Engineering , Pisa, 25-26 September 2008
Solution proposed
• UbiDraw
– Vectorial hand drawing application that adapts its user interface.
• displaying, undisplaying, resizing, and relocating tool bars and icons
• according to the current user’s task, the task frequency, or the
user’s preference for some task.
– The context watcher sends this information to the ubiquitous widgets so as
to support task-driven plasticity.
– supports task-driven plasticity based on a small toolkit of task-driven plastic
widgets, called UbiWidgets.
• Usability evaluation
– investigates the effect of using UbiWidgets on the user preference by
conducting some usability testing.

10. 10 HCSE 2008, 2nd Conference on Human-Centred Software
Engineering , Pisa, 25-26 September 2008
Outline
• Introduction
• Related Work
• UbiDraw
• Evaluation
• Conclusion

11. 11 HCSE 2008, 2nd Conference on Human-Centred Software
Engineering , Pisa, 25-26 September 2008
Multiplicity of contexts of use
Location Role Device Experience
Sporting Multimedia Travel programme
Working Travel booking site
Powerful interface for complex operations
Travelling Booking notification
Everywhere connectivity for simple data exchange
Family TV is multi-media family device #1
• Context of use = (User, Platform, Environment)

12. 12 HCSE 2008, 2nd Conference on Human-Centred Software
Engineering , Pisa, 25-26 September 2008
Environment T
Cameleon Reference Framework
Final user
Interface T
Concrete user
Interface T
Task and
Domain T
Abstract user
Interface T
T=Target context of use
Concrete user
Interface S
Final user
Interface S
Task and
Domain S
Abstract user
Interface S
S=Source context of use
Reification
Abstraction
Reflexion
Translation
UsiXML
unsupported
model
UsiXML
supported
model
User S Platform S Environment S Platform TUser T

13. 13 HCSE 2008, 2nd Conference on Human-Centred Software
Engineering , Pisa, 25-26 September 2008
Related Work
• software probe allows deploying interactive systems that constantly
probe the context of use for a significant change and that reflect such a
change into a UI adaptation.
[Calvary, Coutaz and Thevenin 2001]
[Jabarin and Graham 2003]

14. 14 HCSE 2008, 2nd Conference on Human-Centred Software
Engineering , Pisa, 25-26 September 2008
Related Work
• The implementation is independent of the underlying computing
platform and that offers multiple representations of concrete UIs for the
same description.
[Schneider et al. 2002]

15. 15 HCSE 2008, 2nd Conference on Human-Centred Software
Engineering , Pisa, 25-26 September 2008
Related Work
• A toolkit of context-aware widgets that embed plasticity: in this toolkit,
widgets have been abstracted with respect to the underlying physical
environment so as to form platform-independent widgets. These
widgets can also change their interaction modality.
[Crease et al. 2000]

16. 16 HCSE 2008, 2nd Conference on Human-Centred Software
Engineering , Pisa, 25-26 September 2008
Related Work
• Comets propagates interaction needs from the final UI to the task and
domain level through concrete and abstract UIs via a set of logical
mappings.
[Demeure et al. 2000]

17. 17 HCSE 2008, 2nd Conference on Human-Centred Software
Engineering , Pisa, 25-26 September 2008
Our Work
• It drives the plasticity mechanism from a task model located at the task
& domain level. A change of the context of use is firstly interpreted in
terms of a task variation that is then reflected into the Concrete UI level
and Final UI level, respectively.

18. 18 HCSE 2008, 2nd Conference on Human-Centred Software
Engineering , Pisa, 25-26 September 2008
Outline
• Introduction
• State of the Art
• UbiDraw
• Evaluation
• Conclusion

19. 19 HCSE 2008, 2nd Conference on Human-Centred Software
Engineering , Pisa, 25-26 September 2008
UbiDraw
• Develop in a multi-platform environment (Mozart)
• Using a multi-paradigm language (Qtk based on Oz programming)
• Functionalities are group by similarities in tool bars:
– File
– Draw
– Options
– Retouch
• Every toolbar can be displayed at different locations depending on
screen size and resolution of the application running on a particular
platform

20. 20 HCSE 2008, 2nd Conference on Human-Centred Software
Engineering , Pisa, 25-26 September 2008
UbiDraw
• Each group may be displayed in three different ways according with its
status
Hidden Vertical Horizontal

21. 21 HCSE 2008, 2nd Conference on Human-Centred Software
Engineering , Pisa, 25-26 September 2008
UbiDraw
• To determine the size of a non-hidden toolbar and how many icons
should be displayed
– the last icon being clicked,
– the rank representing the users’ preference/need for this icon, and
– the amount of clicks on this icon.
– The higher the priority of an icon is, the more likely it will be displayed

22. 22 HCSE 2008, 2nd Conference on Human-Centred Software
Engineering , Pisa, 25-26 September 2008
Software Architecture
• The process of plasticity is located at the UI control component: the
plasticity is regulated at the highest possible level in the meta-model.
• In this case, only control rules govern the plasticity.
CUI

23. 23 HCSE 2008, 2nd Conference on Human-Centred Software
Engineering , Pisa, 25-26 September 2008
Run-Time Plasticity in UbiDraw
• Steps for run time plasticity as it is implemented in UbiDraw
• Adaptation with UbiDraw always results from user initiative

24. 24 HCSE 2008, 2nd Conference on Human-Centred Software
Engineering , Pisa, 25-26 September 2008
UbiWidget

25. 25 HCSE 2008, 2nd Conference on Human-Centred Software
Engineering , Pisa, 25-26 September 2008
ContextWatcher
• Assign a position and size to each UbiWidget when the context is
changed
• The UbiWidget draw itself
• Strategy :
• Consider UbiWidgets ranking,
– Priority mechanism
– Highest ranking are displayed first
• Display the maximum number of widgets top left of the screen, with
their minimal size

26. 26 HCSE 2008, 2nd Conference on Human-Centred Software
Engineering , Pisa, 25-26 September 2008
Links ContextWatcher and models

27. 27 HCSE 2008, 2nd Conference on Human-Centred Software
Engineering , Pisa, 25-26 September 2008
ModifyConfig
• Goal : reconfigure the adaptation of the UbiMenuBar
• Result: adaptivity & adaptability

28. 28 HCSE 2008, 2nd Conference on Human-Centred Software
Engineering , Pisa, 25-26 September 2008
ContextWatcher Size allocation
• Example :

29. 29 HCSE 2008, 2nd Conference on Human-Centred Software
Engineering , Pisa, 25-26 September 2008
Outline
• Introduction
• State of the Art
• UbiDraw
• Evaluation
• Conclusion

30. 30 HCSE 2008, 2nd Conference on Human-Centred Software
Engineering , Pisa, 25-26 September 2008
Method
• Questionnaire-Based evaluation
• 9 users : not enough but better than nothing!
– Level of expertise using a PocketPC
– Familiarity with computer supported drawing
• Task Analysis – Four different task
1. Load an existing drawing - PocketPC
2. Draw a line - PocketPC
3. Draw a rectangle with mid-sized lines - PocketPC
4. Draw a house, resizing the canvas - Desktop
• The first three tasks had to be realized as quick as possible.
• Users were explicitly invited to test the plasticity of the application, that
is to say to resize the main window to fit their task
• Users were asked to indicate which adaptation mechanism they
favored
– ranking click number, click number Ranking

31. 31 HCSE 2008, 2nd Conference on Human-Centred Software
Engineering , Pisa, 25-26 September 2008
Method
• The user was then invited to rank the available tasks according to his
preferences
• They were then invited to test the application with and without his
customized ranking.
Questionnaire
– The results were collected in a questionnaire with items represented
according to 7-point Likert scale.
Strongly Disagree 1 2 3 4 5 6 7 Strongly Agree (N/A)
– Some space was left at the end of the questionnaires for positive and
negative aspects, and for further comments.

32. 32 HCSE 2008, 2nd Conference on Human-Centred Software
Engineering , Pisa, 25-26 September 2008
Results and Discussion
• User Testing
• Preferences
• Results

33. 33 HCSE 2008, 2nd Conference on Human-Centred Software
Engineering , Pisa, 25-26 September 2008
Outline
• Introduction
• State of the Art
• UbiDraw
• Evaluation
• Conclusion

34. 34 HCSE 2008, 2nd Conference on Human-Centred Software
Engineering , Pisa, 25-26 September 2008
Conclusion
• Original properties
– A unique form of plasticity
– A task-driven mechanism
– An instantiation of the general software architecture for plasticity
– A distribution of responsibilities
– A reasonable usability
– Consistency
– Continuity
• Further investigation is required to fully assess the usability properties
of interest that are predefined in the plasticity notion.
• UbiDraw is restricted to a simple context change: window resizing and
change of platform
• We did not investigate further how other changes of contextual
properties may significantly or not affect the UI plasticity.

35. 35 HCSE 2008, 2nd Conference on Human-Centred Software
Engineering , Pisa, 25-26 September 2008
Thank you very much for your attention
For more information and downloading,
http://www.isys.ucl.ac.be/bchi
http://www.usixml.org
User Interface eXtensible Markup Language
http://www.similar.cc
European network on Multimodal UIs
Special thanks to all members of the team!