Model-based User Interfaces Incubator Group Charter

The mission of the Model-based User Interfaces Incubator Group, part of the Incubator Activity, is to evaluate research on model-based user interface design as a framework for authoring Web applications and with a view to proposing work on related standards.

Join the Model-based User Interfaces Incubator Group.

End date 30 April 2010
Confidentiality Proceedings are public
Initial Chairs Dave Raggett
Initiating Members
Usual Meeting Schedule Teleconferences: Fortnightly,
Face-to-face: two or three times


Research work on model-based design of user interfaces has sought to address the challenge of reducing the costs for developing and maintaining user interfaces through a layered architecture that separates out different concerns:

  1. Application task models, data and meta-data
  2. Abstract Interface (device and modality independent, e.g. select 1 from N)
  3. Concrete Interface (device and/or modality dependent, e.g. use of radio buttons)
  4. Implementation on specific devices (e.g. HTML, SVG or Java)

Each layer embodies a model of behavior (e.g. dialog models and rule-based event handlers) at a progressively finer level of detail. The relationships between the layers can be given in terms of transformations, for example, between objects and events in adjoining layers. XML is well suited as a basis for representing each layer, with the possible exception of the final user interface, which may be generated automatically, guided via author supplied policies.

High level development suites can be provided to shield authors from the underlying XML representations. For example, a data model could be manipulated as a diagram, while the user interface could be defined via drag and drop operations together with editing values in property sheets. The development suite is responsible for maintaining the mappings between layers and verifying their consistency. Authors can choose to provide alternative mappings as needed to address different delivery contexts.

In Scope

The Model-based User Interfaces Incubator Group will evaluate research on model-based design, including end to end models that extend beyond a single Web page, and assess its potential as a framework for developing Web applications. This will involve consideration of use cases and requirements, the role of existing standards such as SCXML, DIAL/XHTML2 and XForms, and making proposals for new work on standards where appropriate.

Out of Scope

Themes define the detailed presentation and behavior for physical realisations of the Concrete UI. The mechanisms for "theming" a Concrete UI are out of scope for this XG, although it should be possible to identify which theme is to be applied. Note that the use of graphics (including SVG) as part of the Concrete UI remains in scope.

The concrete representation and modelling of Voice and multimodal interfaces is out of scope, but could be the subject for a follow on XG.

Success Criteria

The XG will be judged successful if its work is picked up in part or in whole by W3C Working Groups, such as the Ubiquitous Web Applications Working Group, whose charter is due for renewal in 2009. In addition, it is hoped that the XG will be successful in highlighting the role of XML for authoring as distinct from markup intended for direct interpretation by client platforms.


The prime deliverable for the Model-based UI XG will be an XG Report on the potential of model-based user interfaces as a framework for authoring web applications, including a taxonomy of use cases and recommendations for further work. The following would either be part of the XG Report or provided separately:


W3C Groups

Forms Working Group
The XG will liaise with the Forms Working Group on leveraging XForms for model-based design, including application data models and the Abstract UI.
UWA Working Group
The XG will liaise with the UWA Working Group on adapting the user interface to the delivery context, and for a treatment of events in distributed applications.
Voice Browser Working Group
The XG will liaise with the Voice Browser Working Group on the potential of State Chart XML (SCXML) for state dependent models of application behavior.
WAI-PF Working Group
The XG will liaise with the WAI-PF Working Group on the relationship between the WAI-ARIA taxonomy of roles and the Concrete UI layer.
XHTML2 Working Group
The XG will liaise with the XHTML2 Working Group on potential synergies between XHTML2 and markup for the Abstract UI layer.
XSL Working Group
The XG will liaise with the XSL Working Group on the use of XML for Concrete UI and potential synergies with XSL-FO.

External Groups

There are no direct dependencies on external groups, but the XG will study existing work relating to task and data models for user interfaces. Relevant work includes business processes models, user interfaces for embedded devices in distributed environments (for monitoring, supervision and control), and work on service composition (mashups). For the concrete UI, the XG will seek to enable a wide range of delivery channels, and this will necessitate a study of existing solutions.


It is envisioned that the XG will teleconference fortnightly at a time that provides an adequate compromise over the various time zones of the interested participants. Extensive discussion will also be carried out on the XG mailing list. Additionally, it may be useful to have two or three face-to-face meetings at a venue for which a significant number of XG participants are likely to attend.

Expected participation follows the W3C Process Document discussion of Good Standing.


This group primarily conducts its work on the public mailing list public-xg-model-based-ui@w3.org (archive). The group's Member-only list is member-xg-model-based-ui@w3.org (archive).

Information about the group (deliverables, participants, face-to-face meetings, teleconferences, etc.) is available from the Model-based User Interfaces Incubator Group home page.

Decision Policy

As explained in the Process Document (section 3.3), this group will seek to make decisions when there is consensus. When the Chair puts a question and observes dissent, after due consideration of different opinions, the Chair should record a decision (possibly after a formal vote) and any objections, and move on. This charter is written in accordance with Section 3.4, Votes of the W3C Process Document and includes no voting procedures beyond what the Process Document requires.

Patent Policy

This Incubator Group provides an opportunity to share perspectives on the topic addressed by this charter. W3C reminds Incubator Group participants of their obligation to comply with patent disclosure obligations as set out in Section 6 of the W3C Patent Policy. While the Incubator Group does not produce Recommendation-track documents, when Incubator Group participants review Recommendation-track specifications from Working Groups, the patent disclosure obligations do apply.

Incubator Groups have as a goal to produce work that can be implemented on a Royalty Free basis, as defined in the W3C Patent Policy

The W3C Team is responsible for notifying all Participants in this Incubator Group in the event that a new Working Group is proposed to develop a Recommendation that takes the XG Report as an input.

For more information about disclosure obligations for this group, please see the W3C Patent Policy Implementation.

About this Charter

This charter for the Model-based User Interfaces Incubator Group has been created according to the Incubator Group Procedures documentation. In the event of a conflict between this document or the provisions of any charter and the W3C Process, the W3C Process shall take precedence.

Chater update history:

Further Reading

Dave Raggett, JustSystems

$Date: 2010/04/06 13:09:46 $