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Re: A look at WoT specs from Linked Data and AWWW perspective

From: Dave Raggett <dsr@w3.org>
Date: Fri, 6 Apr 2018 10:03:32 +0100
Message-Id: <644CCA0E-3936-49FD-AB63-DFE87DE3328F@w3.org>
Cc: Martynas Jusevičius <martynas@atomgraph.com>, "public-wot-wg@w3.org" <public-wot-wg@w3.org>
To: "Charpenay, Victor" <victor.charpenay@siemens.com>


> On 6 Apr 2018, at 09:24, Charpenay, Victor <victor.charpenay@siemens.com> wrote:
>  
> > JSON is only one of the syntaxes -- RDF is the model, and constraints should be based on it.
>  
> Not exactly. RDF is the foundation of the TD model, sure. But the schemas embedded in a TD model the data a device exposes, not the TD. That data model can be based on SenML or the BLE GATT specification, for instance. WoT devices typically exchange once a TD and ten, hundred times sensor data. It is important to optimize the latter exchanges; RDF would introduce a significant overhead and is therefore not a good candidate. If it is necessary to merge data and meta-data (e.g. a TD or some SSN description of a system), one would have to perform RDF lifting, which is a pretty well-known procedure (see for instance, RML or SPARQL Generate).

I am not quite sure what Martynas is signifying in his comment.  I agree with the idea that constraints should be expressible in terms of the RDF model for how applications expose and interact with things as objects. However, there is developer interest in simple use of JSON to express data types. This can be mapped to constraints on the corresponding RDF model and as you suggest to RDF shape rules in SHACL, however, applications can more simply directly use the JSON expression to apply the constraints to the data.

Dave Raggett <dsr@w3.org> http://www.w3.org/People/Raggett
W3C Data Activity Lead & W3C champion for the Web of things 







Received on Friday, 6 April 2018 09:03:41 UTC

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