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Re: POWDER - is it used?

From: Phil Archer <phila@w3.org>
Date: Tue, 10 Jan 2017 10:21:24 +0000
To: semantic-web@w3.org
Message-ID: <0d90d04a-f6a6-e99f-33eb-8afe34d64c4a@w3.org>
I'm obviously interested in any responses to this in case my  assumption 
of a big 'no' turns out to be incorrect (I doubt it). One of the things 
that is on my perma To Do List is to write something (probably a blog 
post) that sets out the bits of POWDER that I think are worth keeping 
or, at least, the ideas that are worth still referring to.

The most usual route by which people come across it is the use of 
wdrs:describedby and its equivalent IANA registered @rel link type (and 
even that I screwed up and had to add an errata [1]).

The bit that I *do* think is worth hanging on to is the grouping 
mechanism [2]. Maybe not exactly as written but the basic method of 
defining a set of resources is semantically rigorous, NP-Complete, and 
the general problem comes up a lot. For example, in the Permissions & 
Obligations Expression WG [3], there are often discussions about how to 
avoid having to assert individual links between resources and the 
licence terms that apply to them or, conversely, enumerating al the 
resources that a particular odrl:Policy applies to. This is exactly the 
kind of thing that POWDER was designed to handle.

POWDER was written at a time when RDF/XML was still the preferred method 
of expressing semantics and the notion of expressing something simply in 
XML that would then be transformed into something with all the semantic 
bells and whistles, using an XSLT that was defined at XML Schema level, 
wasn't seen as crazy. Hindsight is a wonderful thing and all that.

I remember one occasion when DanBri, in conversation with Brain McBride, 
summed up what POWDER was: "it solves aboutEachPrefix."

Well, it offered *a solution.* I wouldn't propose that solution now 
(despite spending many years on it), but I would say the approach to 
grouping is worth taking into account whenever a better method is proposed.


[1] https://www.w3.org/2007/powder/powder-errata#describedby
[2] https://www.w3.org/TR/powder-grouping/
[3] https://www.w3.org/2016/poe/

On 10/01/2017 01:52, chaals@yandex-team.ru wrote:
> Hi,
> I'm poking around to find out if anyone is *using* POWDER - https://www.w3.org/TR/powder-formal/
> cheers
> Chaals
> --
> Charles McCathie Nevile - standards - Yandex
> chaals@yandex-team.ru - - - Find more at http://yandex.com


Phil Archer
Data Strategist, W3C

+44 (0)7887 767755
Received on Tuesday, 10 January 2017 10:21:40 UTC

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