[x3d-public] X3D Semantic Web 2 MAR 2020: ontology review, URI, mapping metadata structures, RDFa

Don Brutzman brutzman at nps.edu
Mon Mar 2 09:30:42 PST 2020 

Attendees: Jakub Flotynski and Don Brutzman

Prior minutes and resources:

* 24 FEB 2020 X3D Semantic Web minutes: otology redirect, conference reschedule, considering Roadmap
   (typo, otology -> ontology)
   http://web3d.org/pipermail/x3d-public_web3d.org/2020-February/011797.html

* X3D Semantic Web Working Group
    https://www.web3d.org/working-groups/x3d-semantic-web

* X3D Ontology for Semantic Web
   https://www.web3d.org/x3d/content/semantics/semantics.html

   TODO which will probably soon change to
   https://www.web3d.org/x3d/content/semantics/ontology.html

Web3D membership has value!  This work really has the potential to change many many things for the better.  Please consider demonstrating your support by joining.

* Join the Web3D Consortium
    https://www.web3d.org/join

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No meeting next week, Don is presenting at

* 3rd U.S. Semantic Technologies Symposium
   March 9-11, 2020 at North Carolina State University, Raleigh, NC
   https://us2ts.org

   Session: Hybrid AI for Context Understanding
   https://us2ts.org/program-hybrid-ai

   "Validating unmanned vehicle missions using ontology-based reasoning"
   (Don Brutzman, Naval Postgraduate School; Richard Markeloff, Raytheon)

covering the following work:

   Ethical Control of Unmanned Systems
   https://savage.nps.edu/EthicalControl

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1. *Conference planning.* Of note: Web3D 2020 has been postponed due to coronavirus concerns.  The committee is working on revised submission dates, working to determine whether they might occur before or after SIGGRAPH 2020 in Washington DC.

* [x3d-public] Web3D 2020 conference dates reschedule to 14-16 November 2020
    https://web3d.org/pipermail/x3d-public_web3d.org/2020-February/011788.html

* SIGGRAPH 2020 in Washington DC, 19-23 July 2020.
    https://s2020.siggraph.org

The Web3D 2020 conference committee's next meeting is this Wednesday night (pacific USA) and a primary topic is new dates for submission deadlines.

Jakub and I plan to write a paper on X3DUOM, which is the basis for X3D Ontology. He had excellent insights regarding themes for this work, we might analyze the X3D Ontology generation process from the semantics point of view:
- what semantics can be taken from the X3D XSD, and then
- what from X3DUOM, which provides more information about X3D than pure XSD, e.g., hierarchies of classes and properties.
X3D XSD + X3DUOM enable generation of the X3D Ontology, which describes the combined semantics in a formal way compatible with the semantic web standards - suitable for reasoning and queries.

Since some coverage of X3D Ontology is already present in recent papers by X3D Semantic Web working group members, we might further focus a Web3D 2020 paper on mappings between ontologies: HAnim, Geometric Topology, general metadata mappings, shape characterization/search, etc.

Of note is that multiple papers might be written (4 pages or 8 pages) that build on this topic.  Clearly an entire session is possible.  It is interesting that the first three implementations are already complete with equivalent expressive power regarding X3D capabilities, and each is tracking along with X3Dv4 finalization.

- X3D Ontology for Semantic Web
- X3DJSAIL Java       Scene Access Interface Library
- X3DPSAIL Python     Scene Access Interface Library
- X3DESAIL ECMAScript Scene Access Interface Library (proposed)
- others?

Programmatic construction and manipulation of models is powerful.  Cross-language capabilities are likely leading us into new areas of capability. Semantic Web reasoning is already cross-disciplinary by nature, so these are potentially powerful relationships.

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2. *URI definition*

Continuing from last week:

> * Official URI namespaces:
>    PREFIX x3do: <http://www.web3d.org/specifications/X3dOntology4.0#>
>    PREFIX x3do: <http://www.web3d.org/specifications/X3dOntology4.0#>
> 
> Note that we are using http (vice https) for the prefix identifier
> since that is also the approach used for XML Schema and DTD.
> The https address all works but http seems more reliable
> as a general identifier.
The word "reliable" above is questionable. Am starting to think that http might be more commonly available than https, but https is more trustworthy.  Since the URI is a label, it follows that an https prefix is not necessarily a blocker if a software tool doesn't recognize a certificate.

I will be looking and asking next week to see if any other projects are using https within their URIs.

Ontologies allow building a Semantic Web Stack and Web of Trust so https may be preferable.

* Semantic Web Stack
   https://en.wikipedia.org/wiki/Semantic_Web_Stack

* Web of Trust
   https://en.wikipedia.org/wiki/Web_of_trust

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3. *General X3D Metadata Mapping*

Given structured metadata in an X3D model, typically:
- head/meta constructs describing the "document", and
- MetadataSet/Metadata* nodes providing typed specific metadata information,

it would be valuable to have a consistent mapping of such information into RDF/OWL triples.

We both think that it is quite possible to have a general/generic approach that works consistently in all Semantic Web syntaxes, mapping the _information_ present within X3D metadata nodes directly to RDF/OWL using Turtle/XML, JSON-LD, RDFa, etc.

Of related note is that X3D Metadata* _nodes_ themselves already works equivalently in all X3D encodings and programming languages:  ClassicVRML, X3D, JSON, JavaScript, Java, Python, someday C++/C# (see Korea implementations) and RDF/OWL using Turtle/XML (available already).

* [x3d] [cad] X3D WG discussions Feb 28 2020 (member only)
   https://www.web3d.org/mailman/private/x3d_web3d.org/2020-February/007820.html

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4. *RDFa*

"RDFa (or Resource Description Framework in Attributes) is a W3C Recommendation that adds a set of attribute-level extensions to HTML, XHTML and various XML-based document types for embedding rich metadata within Web documents."

* https://en.wikipedia.org/wiki/RDFa

We briefly discussed how RDFa and microdata might also be used as a syntax for including semantic information and metadata in HTML.  Leslie Sikos has an excellent treatment of this subject in his book.

* RDFa Primer (third edition)
   https://www.w3.org/TR/rdfa-primer

* Leslie F. Sikos,
   Mastering Structured Data on the Semantic Web:
   from HTML5 Microdata to Linked Open Data,
   Apress Springer Science+Business Media, New York, 2015.
   https://www.apress.com/gp/book/9781484210505

Looking at how others map HTML head/meta information into RDFa will assist us since X3D head/meta structures are identical.

Good topic for future work (as already envisioned in our charter).

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Having fun with X3D Semantic Web!  8)

all the best, Don
-- 
Don Brutzman  Naval Postgraduate School, Code USW/Br       brutzman at nps.edu
Watkins 270,  MOVES Institute, Monterey CA 93943-5000 USA   +1.831.656.2149
X3D graphics, virtual worlds, navy robotics http://faculty.nps.edu/brutzman

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