I like these. With regard to terminology, there are at least three "normative" definitions of the second among ISO standards. 8601, Data Exchange Formats, sanctions everything under the Sun. Maybe everything in the Universe. ISO 31-1 states that "second" without qualification is the SI second. It does not recognize any other kind of second. Other ISO documents define minutes, etc., in terms of unqualified seconds -- by implication, SI seconds. One even defines a second as 1/60th of a minute. It is all over the map. I am working this through ISO, but it is painful. It boils down to "what difference does it make to me?" The fallacy is that standards are not developed for people who don't need them. They are developed for people who do need them, but that constituency is never well represented among the governing authorities.
I will forward the consensus list to colleagues in ISO terminology, who have been forthcoming and force a productive outcome. If it gets too heavy, we can always throw in PHK! Dave Finkleman Senior Scientist Center for Space Standards and Innovation Analytical Graphics, Inc. 7150 Campus Drive Colorado Springs, CO 80920 Phone: 719-510-8282 or 719-321-4780 Fax: 719-573-9079 Discover CSSI data downloads, technical webinars, publications, and outreach events at www.CenterForSpace.com. -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: Wednesday, February 02, 2011 10:01 AM To: [email protected] Subject: LEAPSECS Digest, Vol 51, Issue 8 Send LEAPSECS mailing list submissions to [email protected] To subscribe or unsubscribe via the World Wide Web, visit http://six.pairlist.net/mailman/listinfo/leapsecs or, via email, send a message with subject or body 'help' to [email protected] You can reach the person managing the list at [email protected] When replying, please edit your Subject line so it is more specific than "Re: Contents of LEAPSECS digest..." Today's Topics: 1. Re: Consensus building? (Rob Seaman) 2. Re: LEAPSECS Digest, Vol 51, Issue 7 (Finkleman, Dave) 3. Re: Consensus building? (Rob Seaman) 4. Re: LEAPSECS Digest, Vol 51, Issue 7 (Stephen Colebourne) 5. Re: Consensus building? (Stephen Colebourne) ---------------------------------------------------------------------- Message: 1 Date: Wed, 2 Feb 2011 07:24:44 -0700 From: Rob Seaman <[email protected]> Subject: Re: [LEAPSECS] Consensus building? To: Leap Second Discussion List <[email protected]> Message-ID: <[email protected]> Content-Type: text/plain; charset=us-ascii Stephen Colebourne wrote: > This list is good at disagreeing, but given the brainpower here, perhaps some consensus building might be good? I'll try one approach, and see what happens. This is a good "creative problem solving" exercise. We tried various other approaches back in the day: http://www.ucolick.org/~sla/navyls If folks (on all sides - we have many more than two here) can relax their guard a bit, the exercise may pay off, perhaps surprisingly so. Note that the pay off is most likely to reveal itself in issues around the periphery. This isn't all-or-nothing. As facilitator, Stephen will need the patience of Job. I'll personally refrain from comment for a few rounds. My only suggestion at this point is that declarative statements should be kept as brief as possible. Avoid subordinate clauses and conditionals, rather divide complex assertions into separate simple statements. You might consider a glossary. Rob ------------------------------ Message: 2 Date: Wed, 2 Feb 2011 10:33:55 -0500 From: "Finkleman, Dave" <[email protected]> Subject: Re: [LEAPSECS] LEAPSECS Digest, Vol 51, Issue 7 To: <[email protected]> Message-ID: <[email protected]> Content-Type: text/plain; charset="us-ascii" The consensus list of facts is an excellent idea. I wish the US could do this with health care: implement what everyone can agree with and debate the rest instead of holding everything hostage to winning a minor point. I suggest that the terms second, minute, hour, day, and month stated without qualification have "normative" status: the SI second, 60 SI seconds, 3600 SI seconds, 86,400 SI seconds, and Gregorian calendar numbers of days expressed as 86,400 seconds. Anything else requires qualification such as: mean solar seconds. Actually I can't think of other forms of hour, day, etc. that require qualification, since those are neither fundamental time intervals nor time scales. An initial thought for discussion. Dave Finkleman Senior Scientist Center for Space Standards and Innovation Analytical Graphics, Inc. 7150 Campus Drive Colorado Springs, CO 80920 Phone: 719-510-8282 or 719-321-4780 Fax: 719-573-9079 Discover CSSI data downloads, technical webinars, publications, and outreach events at www.CenterForSpace.com. ------------------------------ Message: 3 Date: Wed, 2 Feb 2011 08:57:32 -0700 From: Rob Seaman <[email protected]> Subject: Re: [LEAPSECS] Consensus building? To: Leap Second Discussion List <[email protected]> Message-ID: <[email protected]> Content-Type: text/plain; charset=us-ascii Um - as I said I will refrain from comment on the assertions. However, I also said a glossary might be a good idea. The "SI second" is a well defined concept. These others certainly have no normative force. In particular, the essence of the problem in front of us is that the Gregorian calendar does not count something called "SI days". Since the exercise is to build as much consensus as possible, we might most productively avoid strong assertions about points in dispute. Regarding vocabulary, I'd suggest that fully qualified terms will raise the fewest hackles. For instance, "SI second" has a very clear meaning, but "second" is ambiguous (and will remain so no matter what action is taken). Rob -- On Feb 2, 2011, at 8:33 AM, Finkleman, Dave wrote: > I suggest that the terms second, minute, hour, day, and month stated > without qualification have "normative" status: the SI second, 60 SI > seconds, 3600 SI seconds, 86,400 SI seconds, and Gregorian calendar > numbers of days expressed as 86,400 seconds. > > Anything else requires qualification such as: mean solar seconds. > Actually I can't think of other forms of hour, day, etc. that require > qualification, since those are neither fundamental time intervals nor > time scales. ------------------------------ Message: 4 Date: Wed, 2 Feb 2011 16:03:51 +0000 From: Stephen Colebourne <[email protected]> Subject: Re: [LEAPSECS] LEAPSECS Digest, Vol 51, Issue 7 To: Leap Second Discussion List <[email protected]> Message-ID: <[email protected]> Content-Type: text/plain; charset=ISO-8859-1 On 2 February 2011 15:33, Finkleman, Dave <[email protected]> wrote: > I suggest that the terms second, minute, hour, day, and month stated > without qualification have "normative" status: ?the SI second, 60 SI > seconds, 3600 SI seconds, 86,400 SI seconds, and Gregorian calendar > numbers of days expressed as 86,400 seconds. Funilly enough, I'll start by disagreeing with those definitions. The meaning of the things named "second" and "day" being key, the best that consensus will agree to is precise definitions, rather than any "land grab" of key terms. The terms SI-based-minute, SI-based-hour and SI-based-day will, I suspect be acceptable to all. At the end of the process, the defniition of the simple terms can then be considered. Statements: - an SI-based-minute is formed from exactly 60 SI-seconds - an SI-based-hour is formed from exactly 60 SI-based-minutes and thus exactly 3600 SI-seconds - an SI-based-day is formed from exactly 24 SI-based-hours and thus exactly 86400 SI-seconds > Anything else requires qualification such as: mean solar seconds. > Actually I can't think of other forms of hour, day, etc. that require > qualification, since those are neither fundamental time intervals nor > time scales. Defining things that are *not* fundamental time intervals nor time scales is key to the problem. I'll resend in the main thread an updated list so far. Stephen ------------------------------ Message: 5 Date: Wed, 2 Feb 2011 16:47:22 +0000 From: Stephen Colebourne <[email protected]> Subject: Re: [LEAPSECS] Consensus building? To: Leap Second Discussion List <[email protected]> Message-ID: <[email protected]> Content-Type: text/plain; charset=ISO-8859-1 Statements so far - disgree or add please (in particular something on UT1/UT/etc as I will only get it wrong...): General: - the terms seconds, minutes, hours and days are overloaded, thus pedantic and explicit terms are used here SI - the SI-second is a standardised unit of measurement - the SI-second is currently defined as a fixed number of transitions of a caesium atom - the current definition of the SI-second was ratified in 1967 - an SI-based-minute is formed from exactly 60 SI-seconds - an SI-based-hour is formed from exactly 60 SI-based-minutes and thus exactly 3600 SI-seconds - an SI-based-day is formed from exactly 24 SI-based-hours and thus exactly 86400 SI-seconds Solar - a solar-day is a measured period of time - the length of a solar day in in SI-seconds varies over time - the length of a solar day in in SI-seconds is on average increasing with time - a solar day is not a fixed number of SI-seconds - a solar-hour is the period of 1/24th of a single measured solar-day - a solar-minute is the period of 1/60th of a solar-hour and thus 1/1440th of a single measured solar-day - a solar-second is the period of 1/60th of a solar-minute and thus 1/86400th of a single measured solar-day Humanity - a humanity-day is a non-scientific, commonly used term understood by 6bn humans - a humanity-day is interpreted in line with the rising and setting of the Sun TAI-2011 - the TAI-2011 time-scale is known as TAI in the year 2011 - the TAI-2011 time-scale is defined as a uniformly increasing count of SI-seconds from a fixed epoch UT-2011 ??? UT1-2011 ??? UTC-2011 - the UTC-2011 time-scale is known as UTC in the year 2011 - the UTC-2011 time-scale is a continuous count of SI-seconds - the UTC-2011 time-scale defines UTC-2011-days - a UTC-2011-day is either 86400 SI-seconds or 86401 SI-seconds long - the additional SI-second in a UTC-2011-day is a leap-second - the presence or absence of a leap-second is determined up to 6 months in advance Lets see, how we go on these... Stephen ------------------------------ _______________________________________________ LEAPSECS mailing list [email protected] http://six.pairlist.net/mailman/listinfo/leapsecs End of LEAPSECS Digest, Vol 51, Issue 8 *************************************** _______________________________________________ LEAPSECS mailing list [email protected] http://six.pairlist.net/mailman/listinfo/leapsecs
