RE: FW: Time Ontology: Smallest possible increment-of-time

Thanks, Bart.

I tried thinking last night but couldn’t come up with a plausible but simple example.

Ah, caffeine kicking in this morning:


1.       ‘Ball in’ or ‘Ball out’ detectors for tennis and other sports;

2.       Lighting detection equipment – timing of electromagnetic signature of a lightning stroke to microsecond precision then comparing with two or more other signatures from other distant receivers to deduce the direction and location of actual stroke.
But I am not sure how we would turn these into OWL/Turtle examples.

Maybe for this latter:
Identify start and end instants of signature pattern waveform.
Compare with start and end instants of similar signatures, but check that they are not too far away (i.e. time difference of starts or ends are not more than 18000km/300 000km/s => more than 180 degrees away on a great circle line. Light takes 0.04 seconds to travels the earth’s diameter

Millisecond precision would locate stroke only to nearest 300km - not good enough.
Microsecond precision would locate stroke to about nearest 300m – good enough.
Nanosecond precision  would locate stroke to about 30cm – too hard to do, and not very meaningful.

Would that do?

Chris

From: Bart van Leeuwen [mailto:bart_van_leeuwen@netage.nl]
Sent: Thursday, April 13, 2017 8:19 AM
To: Little, Chris
Cc: christoph@hbz-nrw.de; public-sdw-comments@w3.org; Simon.Cox@csiro.au
Subject: Re: FW: Time Ontology: Smallest possible increment-of-time

Chris,

As mentioned in my earlier post fractions of seconds is something that is very likely to happen if you use e.g. sensor data, which happens to be another subject for our WG.
Also using standard database functions to extract the xsd:datetime from timestamp fields will always generate fractions for seconds.
If we want to publish (spatial ) data on the web, maintaining the precision is vital, 2 readers now had the initial conclusion that this is not possible with the Time Ontology only after reading the spec in full detail they concluded that the xsd:decimal allows fractions and thus support fractions for seconds.

Therefore I think adding an example with a more precise time serves a purpose which is beyond theoretical, where centidays certainly is.

I'll try to find some time to create a example

Met Vriendelijke Groet / With Kind Regards
Bart van Leeuwen

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From:        "Little, Chris" <chris.little@metoffice.gov.uk<mailto:chris.little@metoffice.gov.uk>>
To:        "bart_van_leeuwen@netage.nl<mailto:bart_van_leeuwen@netage.nl>" <bart_van_leeuwen@netage.nl<mailto:bart_van_leeuwen@netage.nl>>
Cc:        "public-sdw-comments@w3.org<mailto:public-sdw-comments@w3.org>" <public-sdw-comments@w3.org<mailto:public-sdw-comments@w3.org>>, "christoph@hbz-nrw.de<mailto:christoph@hbz-nrw.de>" <christoph@hbz-nrw.de<mailto:christoph@hbz-nrw.de>>, "Simon.Cox@csiro.au<mailto:Simon.Cox@csiro.au>" <Simon.Cox@csiro.au<mailto:Simon.Cox@csiro.au>>
Date:        13-04-2017 01:02
Subject:        FW: Time Ontology: Smallest possible increment-of-time
________________________________



Bart,

As we can have fractions of a second, why do we need to raise an issue about adding the complications of fragments from another scheme? Or adding milliseconds, but not centidays, megayears, etc.

Would you be happy to close the issue?

Or write a brief example?

Chris

From: Bart van Leeuwen [mailto:bart_van_leeuwen@netage.nl]
Sent: Monday, April 10, 2017 3:12 PM
To: Christoph, Pascal
Cc: public-sdw-comments@w3.org<mailto:public-sdw-comments@w3.org>
Subject: Re: Time Ontology: Smallest possible increment-of-time

Hi,

I had exactly the same observation as Pascal, including the same revelation that xsd:decimal actually allows fractions.
This was also my comment on a earlier request for review [1]

I've created ISSUE-157 to add a example with fragments to the specification

[1] https://lists.w3.org/Archives/Public/public-sdw-wg/2016Dec/0196.html


Met Vriendelijke Groet / With Kind Regards
Bart van Leeuwen


twitter: @semanticfire
tel. +31(0)6-53182997
Netage B.V.
http://netage.nl<http://netage.nl/>
Esdoornstraat 3
3461ER Linschoten
The Netherlands
[cid:image002.jpg@01D2B439.078A10B0]
-----Original Message-----
From: Christoph, Pascal [mailto:christoph@hbz-nrw.de]
Sent: Friday, April 07, 2017 11:35 AM
To: public-sdw-comments@w3.org<mailto:public-sdw-comments@w3.org>
Subject: Re: Time Ontology: Smallest possible increment-of-time

Ah - uh.
I see now that 'xsd:decimal' already allows exactly for the fractions of a second! Duh!

pascal


From:        "Christoph, Pascal" <christoph@hbz-nrw.de<mailto:christoph@hbz-nrw.de>>
To:        public-sdw-comments@w3.org<mailto:public-sdw-comments@w3.org>
Date:        07-04-2017 12:24
Subject:        Time Ontology: Smallest possible increment-of-time
________________________________

Hello *,

what's the smallest duration of time one can specifiy with the proposed time
ontology? I wonder if it's really a full "second"? (Couldn't find anything
smaller but may have missed it).

Analog to spatial ontology, where you can define very (indefinitely?) small
spatial dimensions, this should be also possible within the time ontology.

If you would allow 'https://www.w3.org/TR/xmlschema11-2/#nt-seFrag' (instead of
xsd:decimal) as datatype for time:second you wouldn't even need tons of new
properties to be able to be arbitrarily precise.

If it's too nice for one to always assume decimal numbers when hitting
time:second I would propose one new time:TemporalUnit property (say:
time:secondFrag) which would suffice to define every time(t), where "t < 1s".

pascal

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