TOTAL STRAW DRAFT

Version as of January 15, 2006.

Feedback welcome; preferably via the public-owl-dev@w3.org mailing list. 

The charter should be scoped so as to constrain the WG to produce a relatively small, predictable addition to OWL. The motivations for such an addition include:

• Consideration of the Webont WG's many postponed issues, and the partially met or unmet goals.
• Recent work by theoreticians and implementors shows that there are some "easy wins" that would partially meet some long standing user demands.
• Without ongoing development, users (and potential users) with currently unsatisfied requirements may consider moving away from OWL. (Must be balanced with need to avoid destabalisation.)
• Some things can be and perhaps properly are handled by other groups, but other things really seem to require work on OWL itself (such as QCRs or axiom annotations).
• Making OWL more XML friendly, on the one hand, and human reader friendly, on the other, could help adoption by new user communities.
• Other (potentially important) issues (such as synthesis with other languages/paradigms) should be excluded if they are not currently well enough understood or lack community consensus.
• The WG should be tightly focused and of short duration; the charter should facilitate this without being too restrictive.

This draft was written by Bijan Parsia and Ian Horrocks with feedback from various people, especially the attendees of OWLED 2006.

Change log:

• Address Hendler's second comment
• 15-01-2006 Tweaked the language for the illustration of species rationalization to explicitly include "usable" and modified the deliverables to mitigate the perceived bias of "tractable fragments"; also changed "tractable fragments" to "species" in the discussion of what the wg can add or remove --BJP
• 15-01-2006 Tweaked deliverables to say more clearly that the group could update or refactor the prior OWL recommendations --BJP
• Addressing Hendler's first comment, basically adopting Connolly's proposal
• 15-01-2006 Tweaked schedule to explicitly allow for up to 3 F2Fs ("up to" in the sense of 0-3; 0 is still possible) -- BJP

[NewWebOnt]Working Group Charter

Modified from WS-Policy charter

The mission of the [NewWebOnt] Working Group, part of the Semantic Web Activity, is to produce W3C Recommendations for an extension to the Web Ontology Language (OWL) by refining the “OWL 1.1” Member Submission; it will address implementation experience and interoperability feedback (from the OWL 1.1 Member Submission), maximize compatibility with existing OWL ontologies, and produce a test suite and suitable outreach material.

OWL 1.1 grew out of the first OWL: Experiences and Directions (OWLED) workshop. It represents a relatively small set of extensions of OWL that 1) have been identified by users as widely needed and 2) have been identified by tool implementors as reasonable and feasible extensions to current tools. At the second OWLED workshop, multiple implementations of editors and reasoners for OWL 1.1 were demonstrated, validating the design. Users at the workshop indicated that this relatively small addition to OWL would address a wide class of needs and help further adoption of OWL.

OWL 1.1 also tried to refine certain aspects of OWL based on user and implementor experience; e.g., by tightening of the specification of the abstract syntax of OWL so as to better support APIs, and to allow for a deterministic and round-tripable mapping from the abstract syntax to RDF graphs.

This Working Group shall be schedule-driven and OWL 1.1 shall remain compatible, to the extent possible, with existing implementations and uses. This charter features an aggressive schedule and a tightly constrained scope designed to ensure that the [NewWebOnt] will meet its schedule. This charter is intended to carry OWL consensus and interoperability forward, as outlined in Tips for Getting to Recommendation Faster.

Scope

The [NewWebOnt] Working Group is chartered to provide incremental extensions to the Web Ontology Language (OWL). The extensions are of the following sorts:

• Extensions to the logic underlying OWL, adding new constructs that extend the expressivity of OWL (e.g., qualified cardinality restrictions).
• Extensions to the datatype support provided by OWL, e.g., with XML Schema Datatypes and datatype facets.
• Additional syntactic sugar, i.e., constructors that do not extend the expressive power of OWL, but that make some common modelling paradigms easier to express (e.g., disjoint unions).
• Refinement of the OWL specification, e.g., a rationalization and tightening of the specification of the abstract syntax of OWL so as to better support APIs, and to allow for a deterministic and round-tripable mapping from the abstract syntax to RDF graphs.
• Additional concrete syntaxes for OWL ontologies. Notably, a new XML format designed for easy parsing and maximal compatibility with current XML practices.
• Rationalization of the species of OWL. For example, identifying useful and usable sub-languages that are (more) tractable and/or efficiently implementable, e.g., with standard relational and deductive database technology.
• The Working Group should determine whether continuing the "species" framework for end users is the best way to serve the OWL community, or whether the identification of interesting fragments by the Working Group is "merely" informative.

The starting point for the Working Group is the OWL 1.1 member submission: it defines expressive extensions for OWL, refined abstract and XML syntaxes, and a mapping from the abstract syntax to RDF; it also identifies several tractable fragments of OWL. In order to help the Working Group to stay on schedule, this charter requires Working Group consensus to add expressivity to OWL beyond that in the OWL 1.1 member submission. The charter does not require Working Group consensus to remove some of the additional functionality if it turns out to lead to unanticipated difficulties. This charter also does not require Working Group consensus to add additional concrete syntaxes (e.g., more "user friendly" syntaxes), or to extend the range of species that are identified; such extensions will, however, only be considered provided that they do not have any adverse impact on the schedule.

The Working Group will work to ensure a smooth transition from OWL to OWL 1.1 by providing suitable outreach documents (whether new or as updates to existing documents), and by striving to maximize backwards compatibility, especially of ontologies.

The Working Group will develop an extension to the OWL Test Suite covering the new functionality (and optionally more extensive coverage of old functionality), and differences, if any, with the existing language.

Out of Scope

• Query languages (see the DAWG for SPARQL/DL)
• Rules (see RIF)

Dependancies

The work is clearly related to the work of the DAWG and RIF Working Groups, but is not dependant on that work. Close coordination with these Working Groups will, however, clearly be mutually beneficial.

Meetings

The [NewWebOnt] intends to rely on distributed meetings; however, if the Working Group determines it is necessary, it may schedule 0 to 3 face-to-face meetings (that is, it is not required to have any F2F meetings, but it may have as many as 3).

At least up until the Last Call period ends, a two-hour Working Group distributed meeting will be held every week; thereafter, a one and half hour Working Group distributed meeting will be held every week. When necessary, e.g., in order to meet agreed-upon deadlines, distributed meetings may be held twice a week.

The [NewWebOnt] Working Group may adjust the timing and duration of meetings to address the workload and assure that the goals and schedule of this charter are achieved.

Deliverables

• Functional-style Syntax (FS)
• Semantics (S)
• Mapping to RDF (RS)
• XML Syntax (XS)
• Tractable Fragments/Rational Species (RaS)
• Outreach material (e.g., overview, guide, etc.)
• Test Suite

The above list refers to functionality not documents. For example, it is up to the Working Group to determine whether having a combined FS, S, and RS document that is a direct update to the OWL Semantics and Abstract Syntax document, or to follow the submission and keep them separate. Similarly, the publication status of each document (Recommendation or Submission) is likewise up to the group.

Schedule

This schedule is aggressive but contains built-in "slop". For example, the first working drafts of most of the documents occur "sometime" in months 2-4.