LISTSERV mailing list manager LISTSERV 16.0

Help for DATETIME Archives


DATETIME Archives

DATETIME Archives


DATETIME@C4VLPLISTSERV01.LOC.GOV


View:

Message:

[

First

|

Previous

|

Next

|

Last

]

By Topic:

[

First

|

Previous

|

Next

|

Last

]

By Author:

[

First

|

Previous

|

Next

|

Last

]

Font:

Proportional Font

LISTSERV Archives

LISTSERV Archives

DATETIME Home

DATETIME Home

DATETIME  November 2010

DATETIME November 2010

Subject:

Re: Types of uncertainty

From:

"Edward C. Zimmermann" <[log in to unmask]>

Reply-To:

Discussion of the Developing Date/Time Standards <[log in to unmask]>

Date:

Mon, 29 Nov 2010 09:54:10 +0100

Content-Type:

text/plain

Parts/Attachments:

Parts/Attachments

text/plain (63 lines)

On Mon, 29 Nov 2010 05:55:16 +0000, Simon Grant wrote 

> But wait a minute.. If I have millisecond precision I must have, at least,
time zone precision.. So where is the interval 1985 defined? By UTC? Or if a
book was published in 1985 in Berlin shall we have call to define the year as
a range using a span of time in Middle European time? 
>  

The standard allows for times to be specified without zone (implicit is the
zone of the speaker).

> Perhaps there isn't a perfect answer to this. But it would be unwise to give
a date as "1985" when you mean the end of 1985-12-31 at a time when other time
zones had already gone over to 1986. 
> 

We then run into a number of problems and can't talk about 12 Dec or 1 Jan,
last day or 1st of the month or even day since the time difference between two
points on the earth can be as much as 24 hours (Adelaide to Alofi in the South
Pacific).


> I think the better analogy is with estimation, as in statistics, where one
routinely sees error bars.

There is a difference between precision and error. Error is about accuracy
while precision is about readability and repeatability. One can have higher
accuracy than the precision of a device just as one can have highly precise
devices with poor accuracy. Expensive lab instruments are about high precision
and high accuracy--- typically also traceable against an accepted national
reference (such as NIST in the US).

ISO8601:2004 gives use also a number of implicit fractional unit precisions.
The expression of time 12:30.5Z is, I'd suggest, not the same as 12:30:30Z
12:30.5 is either reading to 1/10 of a minute or 1/2 a minute.
12:30:30 is implicitly reading to seconds.
In the Hebrew time system I mentioned--- whose reference is 1 degree of
celestial rotation-- we have units of 1/18 minute--- 1080 halakim per hour---
or 3 1/3 seconds.

 
> There is something inherently vague about vagueness. It would be very
peculiar to say something like 2010-11-29T05:52Z +/- P1Y4M23DT4H43M12.358S
(which could be expressed as a datetime value somewhere within a
rather-too-well-defined interval) - so one simply wouldn't, but there seems no
virtue in excluding that possibility from our vocabulary. 
> 
> Simon  
> -- 
> Simon Grant 
> +44 7710031657 
> http://www.simongrant.org/home.html

--

 Edward C. Zimmermann, NONMONOTONIC LAB 
 Basis Systeme netzwerk, Munich Ges. des buergerl. Rechts 
 Office Leo (R&D): 
  Leopoldstrasse 53-55, D-80802 Munich, 
  Federal Republic of Germany  
 http://www.nonmonotonic.net 
 Umsatz-St-ID: DE130492967

Top of Message | Previous Page | Permalink

Advanced Options


Options

Log In

Log In

Get Password

Get Password


Search Archives

Search Archives


Subscribe or Unsubscribe

Subscribe or Unsubscribe


Archives

August 2019
February 2019
December 2018
November 2018
October 2018
January 2018
August 2017
July 2017
June 2017
April 2017
March 2017
February 2017
August 2016
July 2016
May 2016
April 2016
March 2016
February 2016
January 2016
December 2015
November 2015
October 2015
August 2015
July 2015
June 2015
May 2015
April 2015
March 2015
December 2014
November 2014
March 2014
September 2013
May 2013
February 2013
October 2012
September 2012
August 2012
May 2012
March 2012
December 2011
November 2011
September 2011
August 2011
July 2011
June 2011
May 2011
April 2011
March 2011
February 2011
January 2011
December 2010
November 2010
October 2010
September 2010
August 2010
July 2010
June 2010
February 2010
January 2010
December 2009
November 2009

ATOM RSS1 RSS2



LISTSERV.LOC.GOV

CataList Email List Search Powered by the LISTSERV Email List Manager