| CARVIEW |
Device Independence Working Group Charter
This charter is written in accordance with the W3C Process, section 4.2.2 (Working Group and Interest Group Charters).
Table of Contents
- 1 Mission
- 2 Criteria for success
- 3 Scope
- 4 Schedule
- 5 Relationships with other work
- 6 Participation, meetings, and logistics
1 Mission
The Device Independence Working Group (DI WG) is a Working Group as defined by the W3C Process.
The mission of this Working Group is to study issues related to authoring, adaptation and presentation of Web content and applications that can be delivered effectively through different access mechanisms.
In particular the Working Group will:
- collect requirements for Web access via various kinds of presentation device
- review related specifications within and outside of W3C
- provide use cases and requirements to related activities within W3C
- describe techniques which allow authors to better manage device dependencies
- in some specific areas not covered by other groups, to propose recommendations that will lead to enhanced device independence.
2 Criteria for success
The long-term objective of the Device Independence WG is to avoid fragmentation of the Web space accessible with various kinds of presentation device.
The main criteria for success in this long-term objective are that:
- presentation devices can access Web content appropriate for their capabilities
- authors can create Web content that is deliverable across different presentation devices
- W3C Recommendations enable and promote access from different kinds of presentation device
3 Scope
During its first year (February 2001 - February 2002), under its previous charter, the Device Independence WG 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.
At the Delivery Context Workshop in March 2002, feedback confirmed these as focus areas, including the need to better document and provide guidelines for use of existing technologies. This is reflected in the following work items. Overall timescales are shown in the schedule.
NB: All recommendations produced under this charter will make use of existing W3C technologies where appropriate, including the use of XML Schema to define any normative XML constructs.
3.1 Delivery context
Delivery context, in the scope of device independence, relates to the definition, transport and use of device capabilities. The existing Composite Capabilities/Preferences Profile Working Group is defining a general framework for representing capabilities and preferences. In due course, it is expected that the DI WG will take over responsibility for this framework. The following work items have been additionally identified in this area.
3.1.1 Work item: Delivery context overview
Growing out of requirements investigations already being undertaken within the WG, this work item will produce a W3C Note that provides an overview and positions the different technologies that are involved in the description, transport and use of device capabilities. The work item will identify, from a systems perspective, how delivery contexts:
- are expressed in terms of specific attributes - this will also guide the core device vocabulary work item
- are requested, exchanged and, if necessary, negotiated, cached and resolved, such as using the CC/PP framework - this will also guide the protocol work item
- are made accessible to authors, such as in stylesheets and document profiles - this will also contribute to the document profile work item
The deliverable will provide a framework that will guide and motivate other delivery context work items.
Deliverable: Note
Dependencies: none
Timescale: Note - 4 months
3.1.2 Work item: Core device attributes
Following the interest shown at theDelivery Context Workshop, this work item will start a W3C Recommendation track on a set of Core device presentation attributes, with the following objectives:
- consolidate earlier inconsistent attempts to define device vocabularies (Conneg Media Feature Sets, CC/PP example vocabulary, UAProf, Media Queries)
- define, in a modular form, a core set of device attributes whose definitions could be relied upon by authors when specifying device adaptation
- propose how extended vocabularies could be based on the core
- allow multiple possible representations for attributes (XML, RDF, CSS) depending on the context of use
- itemise relationships between the core attributes and existing attributes in other vocabularies
- provide a foundation for defining device classes based on the core attributes
Some current vocabulary practices have been described in the CC/PP Implementors Guide: Harmonization with Existing Vocabularies and Content Transformation Heuristics
The aim is not to propose a new vocabulary, but to identify core attributes and their semantic meaning, how they map into existing vocabularies (UAProf, CSS Media Queries, etc) and how they may be represented in XML (with appropriate datatypes in XML Schema) or RDF.The first step in this work item will be to produce a detailed requirement document, including end-to-end use cases. This will be a public working draft.
Deliverables: Requirements, Working Drafts, LC, 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; maintenance - +6 months
3.1.3 Work item: CC/PP protocol
The DI WG expects to take over the results of the CC/PP WG when that group finishes its work.
Protocol proposals were explicitly excluded from the scope of the current CC/PP WG. However, it is essential that a protocol is formalised to ensure that compatible implementations based on CC/PP can be developed.The technical work will be hosted by the DI WG, but, because this involves protocol development, the standardization track will be proposed via IETF.
Current protocol practices have been described in theCC/PP Implementors Guide: Privacy and Protocols. The work item will deliver a protocol proposal based onHTTP1.1 since an existing proposal for aCC/PP exchange protocol based on HTTP Extension Frameworkhas not been successful because of the lack of support forHTTP-ex. The WAP Forum have createdHTTPextension headers for transporting the UAProf variant ofCC/PP. It may also be necessary to consider howCC/PPprofiles should conveyed as part of other protocols.
Deliverables: Note
Dependencies: Work item: Delivery context
overview
Timescale: Note - 8 months, RFC - +12 months
3.2 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.
This work will include a survey of content adaptation techniques and their use in device independence authoring.
The following work items have been identified.
3.2.1 Work item: Authoring scenarios
In order to motivate further work in this area, this work item will produce a W3C Note that analyzes end-to-end authoring scenarios for device independent Web content and applications.
In particular, the purpose is to set out the different goals of authors, ranging from those of a small static-content website to those of a website delivering complex interactive applications. This can be seen as authoring requirements for device independent authoring techniques.
Deliverables: Note
Dependencies: none
Timescale: Note - 3 months
3.2.2 Work item: Authoring techniques
Based on the previous scenarios, this work item will propose some techniques for authors to achieve greater device independence. The purpose is twofold.
Firstly, using existing techniques, to:
- describe how authors use current markup and adaptation techniques to deliver to different devices
- show how separation between content and its presentation on different devices can be achieved
- cover approaches that include adaptation on the client, the origin server and at intermediaries
- give examples based on existing markup and adaptation techniques
- point out where current approaches do not address all the goals
Secondly, using techniques based on XForms, to:
- show how navigation can be described independently of target device (e.g. for non-visual and different sizes of visual device)
- show how interaction can be expressed in a device independent manner
- show how applications can be customized for different target delivery contexts
As a starting point for the activity, a public Workshop on Device Independent Authoring Techniques will be held to gather input from practitioners and technology providers and to capture best practices for addressing the authoring scenarios.
Deliverables: Workshop proceedings, Note
Dependencies: Work item: Authoring
scenarios
Timescale: Note - 6 months after Workshop
3.2.3 Work item: Interaction markup
An increasing use of the Web is in delivering interactive applications to users. This work item will focus on the syntax and semantics required to describe interaction logic in a device independent manner. From this starting point, following the authoring scenarios and techniques, it would then be possible to adapt the interaction for presentation on different devices.
The work item will consider how to make use of XForms, XHTML and XML Event specifications in combination to express interaction logic. The result of the work item is expected to take the form of comments, change requests and extension requests to the XForms and HTML Working Groups whenever the changes fit the charter and objective of their activities. Other extensions, if needed to express interaction logic in a device-independent manner, would be produced as Requirements leading to a future W3C Recommendation track. Consideration will be given to whether such markup could be a starting point for multimodal interaction, through liaison with the Multimodal Interaction WG.
Deliverables: feedback to other working groups, or
Requirements, Working Drafts, LC, CR, PR, REC
Dependencies: Work item: Authoring
scenarios, XForms, XHTML, XML Event, Device Independent Authoring
Techniques Workshop
Timescale: feedback to other groups - 2 months after Workshop;
(following only if necessary) Requirements - +2 months; 1st Working Draft -
+4 months; Last Call - +6 months; REC - +6 months
3.2.4 Work item: Document profile
A Document Profile is a set of document attributes, defined using an XML or RDF vocabulary, that can be used, for example, when negotiating document customization for different delivery contexts. A set of XHTML Document Profile Requirements 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.
The purpose of this work item would be to identify such document attributes, and to follow a W3C Recommendation track on their definition. In particular, the work item would:
- explore what metadata would be required to express media compatibility, interaction style and other document attributes required for content negotiation and adaptation
- survey existing technologies
- use XML Schema, RDF, and/or RDF Schema in the definition of profiles
- strive for compatiblity with CSS Media Queries and XSLT transformations
Deliverables: Requirements, Working Drafts, LC, CR, PR,
REC
Dependencies: Work item: Delivery context
overview, Work item: Authoring scenarios,
XML Schema, RDF, RDF Schema, Device Independent Authoring Techniques
Workshop
Timescale: Requirements - 3 months after Workshop; 1st Working Draft -
+4 months; Last Call - +5 months; REC - +7 months
3.3 Reviewing
In order to promote awareness of, and appropriate support for, device independence in the creation of other recommendations, there is an ongoing responsibility to monitor and respond to requests for review from other groups, both within W3C and externally. Now that we have established some principles, and in the light of developing the overviews, scenarios and techniques mentioned above, this will become an important way to relate our work to that of others.
3.3.1 Work item: Respond to W3C review requests
When asked to review the output of other working groups, especially at Last Call (but preferably before that), the group will consider whether it has any comments related to device independence to offer, and return them within the requested time period.
Deliverables: Comments in response to review requests
Dependencies: Requests for review from other groups
Timescale: ongoing
3.3.2 Work item: Review external standards
In order to fulfill our mission, and to promote better understanding and coordination across the industry, it is important to monitor the work of external bodies, such as IETF, WAP Forum, 3GPP. See the section on External groups for more details. If their work has implications for Web related device independence, we may provide comments, where appropriate and agreed by the WG, on specific technical issues or on their coordination with W3C activities and recommendations. Partly this may be achieved by WG members also being participants in, or observers of, the external work, or by inviting representatives of these bodies to WG meetings.
Deliverables: Comments on external standards proposals
Dependencies: none
Timescale: ongoing
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 initial charter of the group was from February 2001 to February 2002, which was then extended to the end of May 2002.
This charter is intended to cover the two year period from the beginning of June 2002 to the end of May 2004. However, some work items, due to the unpredictability of the dependencies described above, may require a request to the Director for approval for an extension under this charter to reach completion and allow for maintenance.
4.2 Milestones
For the work items described above, the key milestones are illustrated in the following table:
| Work Item | 06/02 | 07/02 | 08/02 | 09/02 | 10/02 | 11/02 | 12/02 | 01/03 | 02/03 | 03/03 | 04/03 | 05/03 | 06/03 | 07/03 | 08/03 | 09/03 | 10/03 | 11/03 | 12/03 | 01/04 | 02/04 | 03/04 | 04/04 | 05/04 |
| Delivery context overview |
Note | |||||||||||||||||||||||
| Core device Attributes |
Requirements | 1st WD | LC WD | REC | maintenance | |||||||||||||||||||
| CC/PP protocol |
Note | RFC? | ||||||||||||||||||||||
| Authoring scenarios |
Note | |||||||||||||||||||||||
| Authoring techniques |
wkshp | Note | ||||||||||||||||||||||
| Interaction markup |
feedback | Req? | 1st WD? | LC WD? | REC? | |||||||||||||||||||
| Document profile |
Requirements | 1st WD | LC WD | REC | ||||||||||||||||||||
| Reviewing |
ongoing | |||||||||||||||||||||||
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:
- June 2002
- New charter begins
- 27-28 June 2002
- Working Group face-to-face meeting in Ottawa
- September 2002
- Workshop on Device Independent Authoring Techniques
Working Group face-to-face meeting - February 2003
- Working Group face-to-face meeting with W3C Technical Plenary
- June 2003
- Working Group face-to-face meeting
- October 2003
- Working Group face-to-face meeting
- February 2004
- Working Group face-to-face meeting with W3C Technical Plenary
- May 2004
- 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
Within the Interaction Domain, the CC/PP WG is producing a Recommendation for an RDF-based framework for describing device capabilities and user preferences. It is expected that, in due course, the Device Independence WG will take over responsibility for the CC/PP Recommendation from the CC/PP WG.
Previous work by the SYMM WG on SMIL developed markup, such as ‘switch’ and ‘customTest’, that can be used for content adaptation based on delivery context. SVG also supports conditional processing based on ‘switch’ markup.
Also in this domain, the Voice Browser WG is developing markup for voice interaction, which may be particularly appropriate for some mobile devices, while 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. Both groups provide additional targets for delivery of device independent content that we need to take into account when considering delivery context and authoring.
- Documents Format Domain
Within the Document Format Domain, 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.
The CSS WG, through their work on Media Queries, has shown how authors can allow for the capabilities of the delivery device.
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.
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 Device Independence WG participating in the Hypertext Coordination Group.
- Technology and Society Domain
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
The following is a partial list of groups known to be working on the integration of Web technologies into various kinds of devices. This list is not exhaustive, but does represent the major initiatives underway at the time of this proposal for charter.
Coordination will be sought with these groups when appropriate on issues of mutual interest. The coordination mechanisms will vary according to the nature of the issue and depend as well on the processes of the external group. It could be achieved through cross membership or by inviting experts from external groups to participate in our work.
The external groups have been broadly categorized by examination of their charters into areas of relevance to the Device Independence Working Group and its objectives.
5.2.1 The Internet Engineering Task Force
A large open international community of network designers, operators, vendors, and researchers concerned with the evolution of the Internet architecture and the smooth operation of the Internet. Former work by the IETF Content Negotiation (conneg) group is a key reference for some of our work. Future proposals on CC/PP protocol will require good coordination with IETF.
Other related work items have been identified between IETF and W3C, and specifically between DI WG and IETF WGs such as OPES and SIP. Coordination with and review of other W3C Working Groups as described in Section 5.1 will provide a basis for exploring additional synergies between IETF and DI WG, as will the regular coordination call between IETF and W3C representatives.
5.2.2 Wireless technologies
- WAP Forum (Wireless Application Protocol Forum)
- A wireless industry consortia for the development of specifications for mobile devices and data services. It has defined UAProf (based on CC/PP) for representing mobile device profiles. The WAP 2.0 Specifications will be examined for relevance and utility to device independence. Of particular interest is a new WAP Drafting Committee chartered to define a comprehensive set of service requirements for Content Download.
- Wireless Village
- The Wireless Village Initiative for Mobile Instant Messaging and Presence is a wireless industry consortium with established links to de jure standards organizations and related consortia with the mission of utilizing established protocols for exchanging content and user information between mobile devices, mobile services and Internet-based instant messaging services.
- 3GPP (The 3rd Generation Partnership Project)
- 3GPP brings together a number of telecommunications standards bodies under the direction of the Mobile Competence Centre to produce a 3rd generation mobile system based on GSM broadband standards (widely deployed in Europe). 3GPP has established liaisons with ITU, IETF, ISO MPEG, OMG, SyncML, WAP, W3C, GSMA (the major GSM operators), and the leading television industry consortia.
- 3GPP2 (The 3rd Generation Partnership Project 2)
- 3GPP2 was formed under the auspices of ITU and ETSI to produce a 3rd generation mobile system based on CDMA technology (widely deployed in North America and Asia). 3GPP and 3GPP2 have stated their intention to collaborate at the application layer to ensure users transparent access to 3G mobile services independent of location or underlying technology.
5.2.3 Broadcast media
Worldwide radio and TV broadcasters plan tight integration of traditional audiovisual content with web content, data and multimedia services with the arrival of 3G networks. Organizations such as ARIB, ATSC, ATVEF, EBU, OpenCable, and WorldDAB are addressing the integration of networks and broadcast systems, interoperable transport protocols, content negotiation, metadata, and digital rights management. In particular, two broadcast groups with established links to standards work-in-progress are producing detailed specifications in the areas of content negotiation and delivery context are:
- TV-Anytime Forum
- DVB (The Digital Video Broadcasting Project)
5.2.4 Interaction framework
Many IT consortia have focused on interoperability across heterogeneous platforms, which takes on additional complexity in the mobile world. Two groups doing detailed work of potential benefit to device independence in the areas of content origination and negotiation, session management, data synchronization, standardized objects and metadata are:
In addition, two related technical committees within OASIS are working on standards for interaction with web applications, including the delivery of presentations via intermediary portals:
5.2.5 Printer related groups
- Printers are part of the targeted devices for the Device Indepence Working Group. The following group is responsible for the definition of print markup (XHTML-Print) and printer capability descriptions, among other printer-related standards:
PWG(The Printer Working Group)
5.2.6 Other organizations
When appropriate, we will liase with other standards bodies on common areas of interest.
For example, within ISO/IEC JTC 1/SC 29 subcommittee, the MPEG-21 framework for multimedia delivery and consumption may be a relevant area to achieve mutual understanding.
6 Participation, meetings, and logistics
6.1 Participation
To join the Device Independence Working Group, please follow the instructions of section 4.2.3 of the Process Document, sending email to the Working Group Chair and the W3C Team contact. The nomination must include explicit agreement to this charter, including its goals, an IPR disclosure and the level of effort required of the representative.
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. Invited experts are encouraged to adopt the same requirements for meeting attendance and timely response as are required of W3C Members. Invited experts are subject to the same requirement for information disclosure as are required of W3C Members and they have to agree to the W3C invited experts and collaborators agreement.
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 participants in good standing and individuals invited at the discretion of the Chair to specific meetings.
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. Also, the lead of the Device Independence Activity, Kazuhiro Kitagawa is a member of the group.
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 Intellectual property
W3C promotes an open working environment. Whenever possible, technical decisions should be made unencumbered by intellectual property right (IPR) claims.
This is a Royalty Free Working Group, as described in W3C's Current Patent Practice, dated 24 January 2002.
Working Group participants disclose patent claims by sending email to <patent-issues@w3.org>; please see Current Patent Practice for more information about disclosures.