Device Independence Working Group Charter

This charter is written in accordance with the W3C Process, section 6 (Working Group Interest Groups and Coordination Groups).

This charter supersedes the previous Device Independence Working Group Charter.


Table of Contents


1 Mission

The Device Independence Working Group (DIWG) is a Working Group as defined by the W3C Process.

The mission of this Working Group is to study issues and propose solutions related to the creation, adaptation and presentation of Web content and applications that can be delivered effectively through different access mechanisms.

In particular the Working Group will:

2 Criteria for Success

The long-term objective of the DIWG is to enable access to a unified Web from any device in any context by anyone.

The main criteria for success in this long-term objective are that:

3 Scope

3.1 History

During its first year (February 2001 - February 2002), under its first charter, the DIWG set out an overview of its goals and motivation in the Device Independence Principles Working Draft. This identified two specific areas within the scope of our mission where further work was required: delivery context and authoring techniques.

During subsequent work (February 2002 - June 2004), covered by its second charter, the group completed a number of activities related to collection of requirements and analysis of the issues associated with device independence. It also embarked on the definition of some additional capabilities to assist with device independence. The group published a number of notes and working drafts during this period, including an updated version of its principles document.

Delivery Context Overview for Device Independence
W3C Working Draft published in December 2002
Glossary of Terms for Device Independence
Latest published version of the Glossary, published in August 2003
Authoring Challenges for Device Independence
W3C Working Group Note published in September 2003
Device Independence Principles
W3C Working Group Note published in September 2003
Authoring Techniques for Device Independence
W3C Working Group Note published in February 2004
Core Presentation Characteristics: Requirements and Use Cases
W3C Working Draft published in May 2003

During this period, DIWG also took on the role of completing the CC/PP Structure and Vocabularies Specification, which was left unfinished when the CC/PP working group closed. The specification became a recommendation early in 2004.

The analysis work carried out by the group, during its first two charter periods, confirmed the validity of the original focus areas and enabled additional detail to be added to them. The items identified for the period of work covered by this (third) charter are based on the results of that previous work.

3.2 Challenges

DIWG recognizes that the proposed set of line items for this charter period is potentially quite challenging. In particular the group will look for opportunities to move documents concurrently through the relevant W3C processes. This may be particularly appropriate where documents reflect different aspects of a particular piece of work, such as authoring.

In addition, it is possible that after initial work on some items has been undertaken, it may become apparent that the work would be better carried out in another working group or under some joint arrangement. Items for which this possibility is thought to exist have been identified explicitly in the following sections and in the schedule.

3.3 Delivery Context

Delivery context, in the scope of device independence, relates to the definition, transport and use of device capabilities. The following items have been defined in this area

3.3.1 Work item: Complete work on Delivery Context Overview Note

Growing out of requirements investigations already being undertaken within the DIWG, this work item will complete work on a W3C Note that provides an overview of delivery context. and positions the different technologies that are involved in the description, transport and use of device capabilities. The work item has already identified, from a systems perspective, how delivery contexts:

The final deliverable will provide a framework that will guide and motivate other delivery context work items. This work item is close to completion but final publication is anticipated to occur within the new charter period.

Deliverable: Note
Dependencies: none
Timescale: Note - 2 months

3.3.2 Work item: CC/PP Structure and Vocabularies Version 1.1

Revisions to RDF (see for example the RDF Concepts and Abstract Syntax), published early in 2004, provide new facilities that can be utilized by CC/PP. A revised version of the CC/PP structure and vocabularies specification is planned. This new version will also enable revisions to be made based on work carried out in the CC/PP Protocol and Core Presentation Characteristics work items.

Deliverables: Requirements, Working Drafts, LC, REC
Dependencies: Work item: Delivery context overview, availability of suitable implementations of the revised RDF
Timescale: 1st Working Draft - +3 months; Last Call - +5 months; REC - +3 months

3.3.3 Work item: CC/PP Processing and Protocol Version 1.0

Protocol and processing proposals were explicitly excluded from the scope of the CC/PP Structure and Vocabularies recommendation, completed in the DIWG's second charter period. However, it is essential that a protocol is formalized and that processing rules are defined to ensure that compatible implementations based on CC/PP can be developed.

Current protocol practices have been described in the CC/PP Implementors Guide: Privacy and Protocols. The work item will deliver a protocol proposal based on HTTP 1.1 since an existing proposal for a CC/PP exchange protocol based on HTTP Extension Framework has not been successful because of the lack of support for HTTP-ex. The Open Mobile Alliance (formerly the WAP Forum) have created HTTP extension headers for transporting the UAProf variant of CC/PP. Approaches based on such extensions will be considered. In addition, the capabilities available through such mechanisms will also be studied. It may also be necessary to consider how CC/PP profiles should conveyed as part of other protocols such as SOAP.

This work item will also define a set of protocol independent processing rules for CC/PP.

Deliverables: Requirements, Working Drafts, CR, PR, REC
Dependencies: Work item: Delivery context overview
Timescale: Requirements - +3 months; 1st Working Draft - +3 months; Last Call - +5 months; REC - +3 months

3.3.4 Work item: Complete work on Core Presentation Characteristics Version 1.0

This work item completes the work started during the previous charter period on a W3C Recommendation track on a set of Core device presentation attributes, with the following objectives:

Deliverables: Working Drafts, CR, PR, REC
Dependencies: Work item: Delivery context overview
Timescale: 1st Working Draft - +3 months; Last Call - +5 months; REC - +3 months

3.4 Device Independent Authoring

Authoring, in the scope of device independence, relates to the way in which existing markup can be used to achieve more effective content delivery across different devices, or to identifying where further markup may be required.

The following work items have been identified.

3.4.1 Work Item: Language Profile for Device Independence Version 1.0

The Language Profile for Device Independence defines an authoring environment suitable for device independent authoring. It is based on a combination of W3C markup. This includes specific modules from XHTML Version 2, XForms and CSS together with additional modules defined by DIWG. These additional modules cover content selection, layout, aggregation and decomposition, and semantic enrichment. Each is the subject of a specific work item for DIWG. Although intended for use within the language profile for device independence, these additional modules may prove useful in providing device independent capabilities for other markup languages.

As the language profile document describes the relationship between other specifications that are being developed throughout the period of this charter, it will remain in Working Draft while those other specifications are developed. Revisions will be made to the working draft to take account of new specifications as they are developed.

In June 2004, the W3C held a Workshop on Web applications and compound documents. This indicated significant interest in creating a new language profile similar to that being investigated by DIWG with the addition of specifications including SMIL and SVG. Clearly, there is considerable overlap between the items discussed in this workshop and the proposed work within DIWG. DIWG expects to work closely with any groups formed as a result of the workshop. In particular, DIWG will actively pursue the opportunity of using the results of any such working groups in defining the language profile for device independence.

Deliverables: CR, PR, REC
Dependencies: XForms, XHTML 2
Timescale: +2 months; 1st Working Draft - +4 months; Working Draft - + 12 months; Last Call - +6 months; REC - +6 months

3.4.2 Work Item: Complete work on Selection for Device Independence Version 1.0

The Selection markup module is a modular extension to any XML-based markup language that allows specification of those parts that are expressed in a processor and those that are not. A considerable amount of work has already been carried out on this item and the group anticipates publishing a working draft before commencement of the new charter period.

Although intended for use within the language profile for device independence, this module may prove useful in providing device independent capabilities for other markup languages.

Deliverables: CR, PR, REC
Dependencies: None
Timescale: 1st Working Draft - +2 months; Last Call - +4 months; REC - +6 months

3.4.3 Work Item: Layout for Device Independence Version 1.0

The Layout work item defines the mechanism by which coarse-grained specification of overall layout is achieved in support of device-independent authoring.

Although intended for use within the language profile for device independence, this module may prove useful in providing device independent capabilities for other markup languages.

It is anticipated that the results of this work item will be:

Deliverables: Requirements, Working Drafts, CR, PR, REC
Dependencies: XForms, XHTML 2, CSS 3
Timescale: Requirements - +2 months; 1st Working Draft - +4 months; Last Call - +6 months; REC - +6 months

This item is one that potentially might be developed jointly or moved to another group. In particular, if the group chooses CSS as the representation for layout, the result of this work in DIWG may be a set of requirements against a future version of CSS, or the DIWG may decide to define its own CSS properties.

3.4.4 Work item: Aggregation and Decomposition for Device Independence Version 1.0

The Aggregation and Decomposition work item defines the mechanisms by which authors specify the relationship of authored units, delivery units and perceivable units.

Although intended for use within the language profile for device independence, this module may prove useful in providing device independent capabilities for other markup languages.

Deliverables: Requirements, Working Drafts, CR, PR, REC
Dependencies: XForms, XHTML 2
Timescale: Requirements - +2 months; 1st Working Draft - +4 months; Last Call - +6 months; REC - +6 months

This item is one that potentially might be developed jointly or moved to another group.

3.4.5 Work item: Semantic Enrichment for Device Independence

Discussion with various groups, including WAI PF and MMI, has indicated that there is a likely need for representations that allow authors to express additional semantics associated with particular components of a user experience. It is known that various kinds of semantic enrichment can be used to aid, for example, the accuracy with which assistive technologies interpret and repurpose Web pages to enhance accessibility.

The investigation phase will analyze existing experience in this area to try and identify appropriate mechanisms by which additional, user interface- related semantics might be added by authors. The group does not wish to prejudge the outcome of the investigation. However, for the purposes of illustration, it is possible that one outcome might include a small number of markup extensions that represent usage patterns so common that they should be supported directly. Another and possibly alternative outcome might be ways to annotate such usage patterns to indicate additional semantics. As with other work items, DIWG will focus on using existing W3C techniques wherever appropriate and will propose extensions only where necessary. Any extensions proposed will use the modularity of the underlying W3C technology.

The schedule for this item currently indicates a recommendation track deliverable in case the result of the investigation is that extensions are required.

Deliverables: Requirements, Working Drafts, CR, PR, REC
Dependencies: Not known
Timescale: Requirements - +2 months; 1st Working Draft - +4 months; Last Call - +6 months; REC - +6 months

This item is one that potentially might be developed jointly or moved to another group. In particular, if the mechanism for semantic enrichment is determined to be by addition of annotations with appropriate metadata, the results of this work might be requirements on generation of a suitable representation of that metadata using, for example, RDF.

3.4.6 Work item: Metadata for Content Adaptation Version 1.0

This work item covers the identification and specification of metadata associated with authored material that can be used during adaptation. For example, it might include information used during negotiation between a client and a server resulting in selection of a particular representation of a resource. It might also include metadata used during adaptation to provide an appropriate representation for a particular delivery context.

This work was originally based on a set of XHTML Document Profile Requirements that were proposed in 1999 as a Working Draft within the HTML Activity. This predated work on CC/PP. In April 2001, the HTML Activity Lead suggested that the DI WG should take over responsibility for pursuing this further.

DIWG's work on adaptation has indicated that the scope of this metadata may now be greater than originally envisaged. Consequently, to validate the requirements, it plans to hold a workshop on this topic early in the new charter period.

Although the final scope must await the results of the workshop, DIWG anticipates that this work item will include

As with other work items, DIWG will place a high priority on reuse of existing W3C techniques and specifications in this work.

Deliverables: Requirements, Working Drafts, LC, CR, PR, REC
Dependencies: XML Schema, RDF, RDF Schema
Timescale: Requirements - 3 months after Workshop; 1st Working Draft - +4 months; Last Call - +5 months; REC - +7 months

This item is one that potentially might be developed jointly or moved to another group after requirements have been developed.

3.5 Work item: Errata

The DIWG has published a number of documents. It plans to publish more during this third charter period. The group recognizes that there is a need to maintain its published documents. This item covers work associated with such maintenance.

4 Schedule

4.1 Duration

The topic of Device Independence is of long term concern, and it may be expected that its charter will be renewed or extended from time to time. The first charter of the group covered the period from February 2001 to February 2002. The second charter covered the period from February 2002 to the end of October 2004.

The third charter is intended to cover the two year period from the beginning of November 2004 to the end of October 2006.

4.2 Milestones

For the work items described above, the key milestones are illustrated in the following table:

Work Item 09/04 10/04 11/04 12/04 01/05 02/05 03/05 04/05 05/05 06/05 07/05 08/05 09/05 10/05 11/05 12/05 01/06 02/06 03/06 04/06 05/06 06/06 07/06 08/06
Delivery Context Overview Note
CC/PP S&V V 1.1 Rqmts 1st WD LC WD REC (*)
CC/PP Processing and Protocol V 1.0 Rqmts 1st WD LC WD REC (*)
Core Presentation Characteristics V 1.0 1st WD LC WD REC (*)
Language Profile for DI V 1.0 1st WD Working Draft LC WD REC (*)
Selection for DI V 1.0 1st WD LC WD REC (*)
Layout for DI V 1.0 Rqmts 1st WD LC WD REC (*)
Aggregation & Decomposition for DI V 1.0 Rqmts 1st WD LC WD REC (*)
Semantic Enrichment Investigation Rqmts 1st WD LC WD REC (*)
Metadata for Content Adaptation V 1.0 Investigation Wkshp Rqmts 1st WD LC WD REC (*)
Errata Maintenance

(*): REC covers all the process roadmap from CR to REC

Type of Work Color Code
Work on the W3C Recommendation Track
Work Leading to a W3C Note
A Workshop
Ongoing Work
Work on the W3C Recommendation Track potentially outside DIWG

It is expected that parallel work items will be addressed by informal subgroups of the DI WG, with significant overlap of participation. Coordination will be maintained by regular meetings involving the whole group.

Other events are as follows:

November 2004
New charter begins
February 2005
Working Group face-to-face meeting with W3C Technical Plenary
June 2005
Working Group face-to-face meeting
October 2005
Working Group face-to-face meeting
February 2006
Working Group face-to-face meeting with W3C Technical Plenary
August 2006
Charter ends

5 Relationship with Other Work

The Device Independence WG has the dual role of monitoring and reviewing the work of other groups from a device independence perspective, as well as proposing solutions for achieving better device independence in areas not already covered by other groups.

Some of the work items above already have strong connections to other groups. In addition, we need to extend our relationships to other groups, both inside W3C and externally, to increase awareness and support for techniques that can lead to greater device independence.

5.1 W3C Groups and Activities

The Device Independence WG will have to maintain contacts with many other groups within W3C as listed below.

Web Accessibility Initiative (WAI)

Our goal, of making the Web accessible via many kinds of presentation device, could be seen as complementary to the broader user-oriented universal access goals of WAI. We will make use of their experience, especially through the Web Content Accessibility Guidelines WG, User Agent Accessibility Guidelines WG, and Authoring Tools Guidelines WG with accessibility techniques and solutions whenever possible.

In particular, we will coordinate with the Protocols and Formats WG on reviewing technical solutions.

Interaction Domain

Multimodal Interaction WG

Within the interaction domain, one working group in particular has interests that overlap with those of DIWG. The Multimodal Interaction WG is developing markup for synchronization across multiple modalities and devices, which in particular may lead to techniques for spanning visual and voice modalities.

The main areas of mutual interest are centered on Delivery Context. DIWG is working on topics such as the representation of delivery context, and on mechanisms for accessing and transporting it. DIWG is also working on a core vocabulary that expresses those characteristics that are relevant to the provision of appropriate user experiences on a wide range of devices.

The MMI WG has been working on specifications that need to access Delivery Context, particularly in the rather dynamic environment of the Interaction Manager ("Systems and Environment Framework" (S+E)). The MMI WG is currently rechartering, and plans to spin off the S+E work to another Working Group. The DIWG is one potential candidate to take over the S+E work.

Should the S+E work be moved to a working group other than the DIWG, appropriate coordination will be carried out between DIWG and the new WG to ensure that the specification of delivery context meets the needs of both working groups. Particular attention will be paid to compatibility of mechanisms for access to the information within the delivery context and to the specification of the characteristics considered to be core.

Other Working Groups

The HTML WG has, through XHTML and its modularization, provided a common markup framework that is deliverable across a wide range of platforms. It provides a solid foundation for matching the markup to the capabilities of the delivery device. DIWG will liaise with the HTML working group to ensure that appropriate use of HTML is made.

The CSS WG, through their work on Media Queries, has shown how authors can allow for the capabilities of the delivery device. In addition, current and forthcoming versions of CSS provide a sound basis for the provision of additional capabilities for authors to use to achieve device independence. DIWG will liaise with the CSS working group to ensure that appropriate use of CSS is made.

The XForms WG has also led the way in showing how forms-based interaction can be specified in terms of XML Schema separately from their presentation using any particular stylistic markup. Their work will be used as a foundation for our investigations of device independent interaction. DIWG will liaise with the XForms working group to ensure that appropriate use of XForms is made.

Within the Synchronized Multimedia activity are groups carrying out work items such as SMIL and the presentation of timed text. There are areas in which these groups share common interests with DIWG. Specification and use of the characteristics of devices is one such area. Selection of the material to be included for processing is another.

The Voice Browser WG is developing markup for voice interaction, which may be particularly appropriate for some mobile devices. This working group provides additional targets for delivery of device independent content that DIWG may need to take into account when considering delivery context and authoring.

The Internationalization (I18N) Activity can provide input on internationalization aspects, for example when considering delivery context and authoring issues.

Coordination with these and other activities in this domain will also be maintained by the chair of the DIWG participating in the Hypertext Coordination Group.

Coordination between DIWG and these other groups will be carried out through the appropriate mechanisms, such as coordination groups, shared working group membership and regular interchange of ideas.

Technology and Society Domain

The RDF Data Access WG is working on mechanisms that allow RDF-based information to be queried. As CC/PP information is represented in RDF, this work is of considerable interest to DIWG. DIWG will monitor the work of this group and may be able to provide use cases based on the needs of authors. In addition, DIWG expects to make use of the results of this group at some appropriate time in the future.

When considering exchange of information about delivery context, privacy issues, as covered by the Privacy Activity, must be taken into account.

When considering representation of delivery context information and core device vocabulary, the Semantic Web Activity can provide assistance, both via the RDF Core WG and, potentially, the Web Ontology WG.

5.2 External Groups

There are groups external to the W3C with interests that are or may be relevant to DIWG throughout the life of this third charter. The particular set of groups may change over time. DIWG will continue to monitor related work on an informal basis and may seek an appropriate level of coordination if items of mutual interest arise. The normal mechanisms of the W3C will be used in any such efforts.

Two groups in particular have shown special interest in the past in the work currently within DIWG. The first of these is the Open Mobile Alliance, with its work on UAProf. This is particularly relevant to the DIWG work on CC/PP. The second is the Java Community Process (JCP), with its work to implement programming interfaces to CC/PP.

6 Participation, Meetings, and Logistics

6.1 Participation

Instructions for joining the Device Independence Working Group will be available from the Working Group (Member-only) Home Page.

Device Independence WG participation (attending meetings, reviewing documents and preparing drafts) is expected to consume one day per week.

Requirements for meeting attendance and timely response are described in the W3C Process document.

Interested individuals and experts in the field may be invited by the Chair to join the group as W3C invited experts to balance the technical experience of the group. Participation from related standards bodies is strongly encouraged.

6.2 Communications

A public archived mailing list <www-di@w3.org> will be used to distribute working documents and for public discussion on them, and for other public communications.

A Member-only archived mailing list <w3c-di-wg@w3.org> will be used for other discussions, administrative and Member-only communications, such as reviews of Member-confidential documents.

6.3 Group Home Page

The Working Group has a home page (Member-only) that records the history of the group, provides access to the archives, meeting minutes, updated schedule of deliverables, membership list, and relevant documents and resources. The page will be maintained by the W3C Team contact in collaboration with the Chair.

6.4 Meetings

The Working Group will have distributed and face-to-face meetings.

A one hour Working Group distributed meeting (teleconference) will be held every week.

The Working Group may schedule face-to-face meetings in a manner that maximizes co-location with events that Working Group members would be attending anyway. To advance the global perspective of the Consortium, face-to-face meetings will be held on at least two separate continents during each year of the Working Group activity.

Participation in meetings (distributed or face-to-face) is limited to Working Group participants and individuals invited at the discretion of the Chair to specific meetings, as described in section 3.2 of the Process Document.

6.5 Resources

To be successful, we expect the Working Group to have approximately 10 to 15 active participants.

6.6 W3C Team Involvement

The Team contact for the Device Independence Working Group is Stephane Boyera, who is too Device Independence Activity Co-Lead. Also, the other co-lead of the Device Independence Activity, Kazuhiro Kitagawa is a member of the group. It is expected that this Working Group would consume about 0.75 FTE, including administrative logistics.

6.7 Confidentiality

W3C, and all W3C Working Groups, are accountable to the Web community as a whole for the quality of W3C technical work. In support of this public accountability, and to ease cooperation with external bodies, the Working Group makes early working drafts of its documents public, including a summary of any technical decisions on which they are based. Feedback and discussion on early drafts will be encouraged on the public mailing list (see communications). This charter is also public.

Other email discussions, such as those concerning administrative arrangements, discussions prior to releasing early drafts and reviews of documents from other groups, are accessible to W3C Members only.

6.8 Patent Policy

This Working Group operates under the W3C Patent Policy (5 Feb 2004 Version). To promote the widest adoption of Web standards, W3C seeks to issue Recommendations that can be implemented, according to this policy, on a Royalty-Free basis.