Re: Vocabulary 'tutorial'?

On 03/23/2015 10:23 AM, Erik Wilde wrote:
> hello elf.
> 
> On 2015-03-23 10:07, ☮ elf Pavlik ☮ wrote:
>> On 03/23/2015 09:56 AM, Erik Wilde wrote:
>>> i am wondering if/why semantic tooling would even be required. if we say
>>> that AS2 is JSON-based, then there's no requirement to define new
>>> vocabularies with RDF, correct? semantic tooling would be necessary for
>>> those who *want* to use it, but that would be outside of AS's scope.
>> If we design RDF Ontologies, those who want to use them as still JSON
>> can do that thanks to JSON-LD. It comes with certain limitations but we
>> can consider it a Lite mode which will not provide all the robust
>> features. If we don't keep RDF in mind while designing, it may not work
>> very well if someone wants to use more powerful features and treat it as
>> Linked Data.
> 
> that's the point i've been trying to make, and decision we've been
> dancing around for a couple of months. is AS2 JSON-based, or is it
> RDF-based. saying that it's "JSON-LD based" really doesn't solve the
> problem, it simply provides rhetoric to justify our inability to decide.
> 
>>> the approach follows the idea of https://github.com/dret/sedola, which
>>> has the same idea of providing a basic documentation harness (in the
>>> case of sedola it's used for for media types, HTTP link headers and link
>>> relation types), without forcing people to subscribe to a single
>>> modeling framework that's required to formally describe these things.
>> Could you please give an example of how those who want to treat it as
>> Link Data can simply do so? Once again, we can not just say "we don't
>> mind if you try to use it as Linked Data", but if we want to make it
>> possible we must keep it in mind when we design things.
> 
> it all comes down to how things are defined. if we *require* all
> identifiers to be dereferencable, then we (probably) require people to
> publish RDF at those URIs. if one the other hand we treat identifiers as
> identifiers, then it is outside of the scope of AS2 if people decide to
> publish RDF at those URIs. if they do, they're welcome to do so, but if
> they don't, that's fine, too.
> 
> conflating the concepts of identifiers and links can be risky. if AS2
> says that concepts such as activity types and object properties are
> identifiers, then everything works just fine. if otoh AS2 says that
> those concepts must be treated as links, that's a very different design.
Personally I often start with using HTTP URIs which return 404, still at
any time in the future I can simply 'fix' it and return some meaningful
description for those who dereference it. We could recommend using
identifiers for vocabulary terms in such order:
1) Use URIs
2) Use HTTP URIs
3) Provide useful information about term you define for those who
dereference its HTTP URI. You may consider using RDFS and OWL but even
plain text or HTML (from .md) gives a good start!

I would also consider that we recommend

2.5) Publish shared vocabularies under https://w3id.org/ namespace to
ensure longevity of URI other used it their data.

Those who know what they do can simply ignore such recommendations :)

BTW Jason Hagg (xAPI/adlnet.gov) applied to join IG and will bring to
the table very concrete requirements for extending 'verbs' / verb types.

Cheers!


> 
> practically speaking, many linked data implementations treat core
> concepts as identifiers anyway, because otherwise the web would melt
> down under the constant load of implementations pulling in all
> interlinked concepts every time they encounter them, to check if they
> may have changed.
> 
>>> as an experiment, i have created sedola documentation for many W3C and
>>> IETF specs, and despite the fact that these are using different (and
>>> often no) formalisms, this still results in a useful list of the
>>> concepts that matter:
>>> * https://github.com/dret/sedola/blob/master/MD/mediatypes.md
>>> * https://github.com/dret/sedola/blob/master/MD/headers.md
>>> * https://github.com/dret/sedola/blob/master/MD/linkrels.md
>> Looks cool! I guess meant for human consumption and not for machine
>> processing?
> 
> so far i'm just publishing MD because it's easy and it's good to look
> at. it would be trivial to transform it into other metamodels, such as
> JSON, XML, or RDF.
> 
> wrt to human consumption vs machine consumption: machines can understand
> the concepts that have been defined somewhere, so that's already pretty
> useful. and that's really all there practically is, because the vast
> majority of meaningful concepts on the internet and the web today have
> only textual descriptions, so there's nothing to consume for machines
> other than a distilled list of the concepts defined in those specs.
> 
> cheers,
> 
> dret.
>