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Exploring the need for a standard core vocabulary to address evolving delivery context requirements, the challenges with existing vocabularies, suggested properties of a standard vocabulary, and the areas it should cover to ensure interoperability and effective context-aware presentation optimization.
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A Standard Vocabulary for Delivery Context Martin Jones Volantis Systems martin.jones@volantis.com
A Standard Core Vocabulary: Why do we need one? What characteristics should it have? What should it cover? What does this mean for the DIWG?
Observed Issues • Evolving DI requirements are not being properly met by existing device identification techniques • Disappointingly low usage of new delivery context mechanisms • Chicken & egg scenario vis-à-vis user agents and origin servers • Potential for interoperability issues between implementations, resulting from vocabulary mismatch
The Missing Link? Capabilities & Preferences CC/PP Exch. RDF/XML HTTP CC/PP Example Client (User Agent) Origin Server Standard Vocabulary
Existing Vocabularies: • Are domain-specific e.g. WAP UAProf • Are not broad enough in scope to facilitate true context-aware presentation • Provide inconsistent levels of detail • Often weakly specified (too many MAYs) • Are in danger of proliferating
Suggested properties of a standard vocabulary • Comprehensive – enough to cover the majority of needs • Modular – to allow irrelevant parts to be omitted safely from implementations • Detailed – at multiple levels to allow for simple or complex interpretations • Extensible – to allow for additions • Balanced – to provide good coverage in all relevant areas
Which areas should a standard vocabulary cover? • User Agent capabilities • Markup elements, CSS elements, content formats (more than just MIME content types), plug-ins supported/installed, size limits, security • Device capabilities • Input, output, identification, security, physical, ergonomic, add-on modules • Network capabilities • Bandwidth, latency, QoS, security, caching, adaptation • User preferences • Language, modality, accessibility, taste, speed/richness • User environment • Place, position, privacy, mood
What does this means for the work of the DIWG? • Give as much focus to specifying a standard DC vocabulary as to the underlying exchange and negotiation mechanisms • Try to reconcile and build on existing vocabularies but don’t be constrained by them