Program of the
International Symposium on Versioning XML Vocabularies and Systems

Monday 9:00—9:30
This paper has no version: Versioning as a social construct

To declare that something “is” or “has” a “version” is to imply that there is some “original” or true referent for that “version” and that the “version” has some standing in the eyes of some authority. However, whether it be versions of the Bible, versions of documents, or versions of application code, there can be no satisfactory approach to understanding “version” as a purely scalar property. It is necessary to see the concept of “version” for what it is: a social construct that may serve particular needs and may, equally, fail to capture what it is intended to. Understanding this will free us to build information systems that more adequately reflect the mutability of knowledge and its complex relationship with static information.

Monday 9:30—10:00
Versioning fundamentals

Active XML vocabularies change over time, undergoing the inevitable evolution called versioning. Versioning means adding, deleting, or changing the elements, element content, number of occurrences, attributes, or attribute values described by an XML schema. Approaches to versioning fall into several classes, including compatible, backwards-compatible, forwards-compatible, and strategy-what-strategy. Specific rules enable the successful use of these strategies, such as the “must ignore unknowns” rule, the “must understand models” rule, and prescriptions for the use of version identifiers. Basic versioning concepts and vocabulary will be illustrated using a set-based model for determining compatibility.

Monday 10:00—10:30
Axioms of versioning

The problems of language versioning can be better understood with the help of some formal axioms defining the relations among the extensions and semantics of languages. Such axioms allow us to specify what makes one language extensionally, syntactically, or semantically a subset, superset, or equivalent of another. The difference between syntactic and semantic compatibility makes clear how languages can grow in a forward-compatible way. The key to compatible versioning is to assign new semantics in the new version of a language for syntax that was already accepted in the prior version, but to which the prior version assigned no semantics.

Monday 11:00—11:30
Managing multiple vocabularies across a global enterprise

Organizations share vocabularies across disparate user groups and data to maximize the value of their investment in XML, and, without question, those XML vocabularies need to change as the businesses evolve and expand. Managing change to DTDs and schemas is difficult enough with a small group of co-located users working on the same content types. What happens when you have hundreds of XML consumers spread across the globe and they have completely different requirements, systems, and content? Get a view of the challenges of implementing change management and vocabulary versioning on a very large scale.

Monday 11:30—12:00
A non-backwards-compatible update: a difficult decision

The U.S. National Library of Medicine (NLM) Journal/Book Tag Sets have been widely adopted by libraries, archives, and commercial publishers. The users are widely distributed, generally unknown to each other, and in many cases unknown to the Tag Set advisory group, owners, and secretariat. The first five revisions to the Tag Sets were backwards compatible, but the most recent is not. The decision to make a non-backwards-compatible revision was not taken lightly. It was made based on several factors, including a decision to favor the needs of future users over the convenience of current users.

Monday 1:30—2:00
Difficulties designing a publishing workflow for three versions of the Open eBook DTD

Three major platforms eBook platforms, Adobe Digital Editions Reader, Mobipocket Reader, and Microsoft Reader, all report that their input format is OEB DTD. However, based on experience generating eBook output from XML source, we have learned that there are a number of incompatibilities  between the three. We had initially hoped to target a valid intersection of the three. When that proved unsatisfactory, a second  hope was to target a non-validating redundant superset of the three. Finally, renouncing laziness and greed, a generic OEB base with three variant filters was implemented. The speaker is curious as to the assembled experts audience's consensus on both (1) the right way for the OEB versions to have been specified and (2) the right was to program around them as they are specified.

Monday 2:00—2:30
Versions in UBL

UBL offers trading partners a standardized framework of applications for interchanging business documents, and like most “standard” vocabularies has the two-fold problem of different versions of the UBL standard as defined by the UBL technical committee and different customizations defined by communities of users. In addition, there is versioning of deployed code lists defined by trading partners using UBL. Minor versions are kept in sync through prohibition of namespace changes and through elements that identify versions and extensions. An augmented processing model, based on the model in the UBL 2.0 specification, is being considered to support forward compatiblity. XPath files and instance reports can help confirm that UBL customizations are conformant and then create tools to ensure validity of data selection from accepted code lists.

Monday 2:30—3:00
Forward compatibility using XML transform-as-needed (XTAN)

It is often desirable to design vocabularies for forward compatibility, that is, to design them in such a way that domain-specific applications that use them can be adapted to changes in them at minimal (and predictable) costs. XTAN is a vocabulary for annotating XML Schemas to indicate how documents that use certain vocabulary extensions can be transformed by an XTAN preprocessor into documents that do not use those features. The transformation may have specific impacts, including losses of fitness for specific uses in specific domains. By using XTAN, systems can provide forward compatibility: a document that uses features not specified in version n of its vocabulary can be transformed automatically (with some impact) into a version n document. XTAN is being developed to meet the needs of the W3C Rule Interchange Format (RIF) Working Group, but the design is general.

Monday 3:30—5:00
Hyde Park Speaker’s Corner

Symposium attendees will be invited to submit mini-proposals (a title and one sentence descriing the topic) for five minute mini-presentations. If there are more proposals than can be accommodated, proposals from people who have already spoken will be discarded, and random selections from the remaining proposals will be made. As at the “Speaker’s Corner” in London’s Hyde Park, there will be virtually no restrictions on allowed content. However, the Versioning Symposium’s organizers will terminate presentations that are not related to versioning, that are disrespectful of others or their points of view, or that are still incomplete after five minutes have elapsed.

Attendees are welcome to bring (or create on-site) visuals to support their mini-presentations, preferably in HTML on USB flash (thumb) drives. This will make it easy for the presenter to display the visuals without the time-consuming activity of swapping computers and projection cables.

Monday 5:00—5:30
Summary and Wrap Up

There will be a lot of material presented at the Versioning Symposium: prepared presentations, questions and answers following those presentations, and mini-presentations from our Hyde Park Speaker’s Corner. This wrap-up will summarize what we have heard, discussed, and learned in the Symposium. Since it will be composed on the fly, the presenter welcomes audience corrections on the points he inevitably will forget or misrepresent.