Subject: [core] SenML metadata label

From: Ari Keränen <[email-masked]>
Date: Wed, 20 Jul 2016 14:15:42 +0000

Hi,

Another proposed extension for SenML not yet in the draft is a "metadata" field for SenML Records. This could be free-form UTF-8 text, like string value (sv). Unlike sv, you can have this *and* a value.

Use cases include "international names" that you can't use as part of "n" label due to the URI compatible restriction, adding "tags" that describe your data, etc.

This seems like a simple thing with reasonable trade-off between value and extra complexity.

We welcome proposals for the name and label of this thing. I'd suggest "metadata" and "m".

Cheers,
Ari

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From: Cullen Jennings <[email-masked]>
Date: Wed, 20 Jul 2016 16:45:10 +0200

> On Jul 20, 2016, at 4:15 PM, Ari Keränen <[email-masked]> wrote:
> 
> Hi,
> 

Seems like a good addition.

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From: Christian Amsüss <[email-masked]>
Date: Wed, 20 Jul 2016 17:01:55 +0200

> This seems like a simple thing with reasonable trade-off between value and extra complexity.

What kind of data could go there that would *not* belong into
link-format title instead? If title does not fit, why should that
metadata not be in another link-format property?

I consider the "associating meta-data" section applicable here, which
tries to limit static meta-data about resources in SenML. Is this
dynamic data you are proposing to be added there, and what would be
their semantics?

Best regards
Christian

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From: Lennart Dührsen <[email-masked]>
Date: Wed, 20 Jul 2016 18:30:28 +0200

Hi,

> Another proposed extension for SenML not yet in the draft is a 
> "metadata" field for SenML Records. This could be free-form UTF-8 text, 
> like string value (sv). Unlike sv, you can have this *and* a value.
> 
> Use cases include "international names" that you can't use as part of 
> "n" label due to the URI compatible restriction, adding "tags" that 
> describe your data, etc.

I understand the need for additional information. For example, it would
be nice to know what exactly a sensor is measuring (e.g. the temperature
of what object). However, I think SenML should focus on sensor values,
because meta data as I imagine it should be standardized to some extent
as well, and nodes should be able to request meta data independently
from the values.

Shorter things (titles etc) should go into the link format, as Christian
suggested.

For example, a node would request a list of sensors (via resource
discovery), then request meta data for a few sensors/resources, and
based on that meta data decide which values it is interested in.

tl;dr  meta data should be handled independently from values, should go
somewhere else to keep SenML compact

Best,
Lennart

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From: Christian Groves <[email-masked]>
Date: Thu, 21 Jul 2016 06:02:05 +1000

Hello Ari,

Would this be roughly equivalent to the "name": construct from the 
proposed W3C thing descriptions?

Regards, Christian

On 21/07/2016 12:15 AM, Ari Keränen wrote:
> _______________________________________________
> core mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/core
>

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From: Ari Keränen <[email-masked]>
Date: Fri, 22 Jul 2016 20:16:36 +0000

Hi,

Closing this thread: the proposed metadata would have been roughly similar to "name" construct, but at Berlin meeting we decided that such metadata is better to be handled with web links. 

Cheers,
Ari

> On 20 Jul 2016, at 22:02, Christian Groves <[email-masked]> wrote:
> 
> Hello Ari,
> 
> Would this be roughly equivalent to the "name": construct from the proposed W3C thing descriptions?
> 
> Regards, Christian
> 
>