Schema.org can be viewed as a threat or an opportunity for the
Semantic Web. It was founded by a collaboration of Google,
Microsoft (Bing), and Yahoo! as an alternative to RDF or RDFa
for tagging web pages. See http://schema.org/docs/faq.html (01)
With that backing and with the simplicity of the schema.org
notation, the adoption rate of schema.org has been faster
than RDFa and much, much faster than RDF/XML. Some people
have considered that a threat to the Semantic Web. (02)
But a new web site provides a mapping of the full schema.org
type hierarchy to JSON and four notations for RDF: XML,
N3, Turtle, and NTriples. See http://schema.rdfs.org/ (03)
Of those notations, JSON is the most humanly readable and
the most computationally efficient. JSON is the native data
format of JavaScript, and mappings have been defined to all
the major programming languages. See http://www.json.org/ (04)
The original RDF/XML was a disaster for humans and for computers.
It is horribly inefficient for computation, and the native XML
tools that process it are too slow for critical applications.
For that reason, its adoption rate has been glacially slow. (05)
The rapid adoption rate of schema.org and the JSON notation
should be a wake-up call for the Semantic Web. R. V. Guha,
the original designer of RDF, said that he "wished" he could
have used LISP notation for RDF. The JSON notation is
essentially LISP with brackets and curly braces. (06)
The schema.rdfs.org web site is useful for showing how the
Semantic Web tools can interoperate with schema.org. But
anybody who compares JSON to the RDF notations will have
no incentive to adopt any version of RDF. (07)
For these reasons, Schema.org and the JSON notation are the
wave of the future. The W3C cannot compete with Google,
Microsoft, Yahoo!, and other companies that are joining the
consortium. (One example is the Russian search company
Yandex, which is now translating the vocabulary.) (08)
To avoid sinking into irrelevance, the Semantic Web must do
more than specify a way to migrate from XML notation to JSON.
Even declaring JSON to be an alternative is not sufficient.
A modest proposal: (09)
1. Phase out RDF/XML as the official base for RDF. There is
no need to say that it's "deprecated". A softer term would
be IBM's euphemism "functionally stabilized". (010)
2. Adopt JSON notation as the official base, but define a formal
semantics for JSON. Pat Hayes collaborated with Guha to define
the logic base (LBase) for RDF. Pat also worked on the ISO
project for Common Logic (CL) and defined the CL model theory
as an upward compatible extension to LBase. Define the JSON
semantics by a mapping to CLIF (Common Logic Interchange Format).
CLIF uses a LISP-like notation that has an almost one-to-one
mapping from JSON. (011)
3. Use the CL semantics to define other useful logic languages
as extensions to JSON. One example would be a version of OWL
that uses JSON. Another would be a rule language that uses
a Horn-clause subset of CL with a syntax based on JavaScript. (012)
4. The option of writing N-tuples in JSON can support a direct
mapping to and from the tables of a relational database.
The rule language could include a version of Datalog to state
SQL queries, constraints, and updates. The types defined by
schema.org would be a valuable enhancement to SQL. (013)
Common Logic is very expressive, and it is not necessary for the
Semantic Web tools to implement theorem provers for the full
ISO 24707 standard. However, it would be possible to extend
the JSON-based notation to support the full CL semantics. (014)
In fact, the W3C could work with ISO to include a JSON-based
dialect in the next update to the 24707 standard. A collaboration
of ISO, W3C, and the major web companies could establish the
Semantic Web as a solid foundation for mainstream applications. (015)
John (016)
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