# RE: ISSUE-17: Advice for representing a duration

From: Julian, Anthony J. <ajulian@mayo.edu>
Date: Tue, 21 Feb 2006 09:37:23 -0600
Message-Id: <EABAC4AB68F26147A4A99B000FC01897E6AB79@excsrv95.mayo.edu>

At HL7 we have the IVL data type:
<!-- type IVL -->
<x
nullFlavor = (NI | OTH | NINF | PINF | UNK | ASKU | NAV | NASK | TRC | MSK | NA | NP)
operator = (I | E | A | H | P) : I
>
Content: ( low, high, center, width )
</x>

Definition:      A set of consecutive values of an ordered base data type.

Note that the interval boundaries must be of comparable types. It makes no sense to specify the interval between 2 meters and 4 seconds.

Table 45: Components of Interval  Name Type Description
low IVXB             The low limit of the interval.
high IVXB            The high limit of the interval.
center T               The arithmetic mean of the interval (low plus high divided by 2). The purpose of distinguishing the center as a semantic property is for conversions of intervals from and to point values.
width T.diff The difference between high and low boundary. The purpose of distinguishing a width property is to handle all cases of incomplete information symmetrically. In any interval representation only two of the three properties high, low, and width need to be stated and the third can be derived.

In any interval representation only two of the four properties high, low, width and center need to be stated and the other two can be derived. Incomplete intervals exist, where only one property is valued, particularly, when no boundary or center is known, the width may still be known. For example, one knows that an activity takes about 30 minutes, but one may not yet know when that activity is started.

Anthony Julian
Mayo Clinic- Information Services
e-mail ajulian@mayo.edu
Phone 507-266-0958
Page 127-10700

-----Original Message-----
From: public-xsd-databinding-request@w3.org [mailto:public-xsd-databinding-request@w3.org] On Behalf Of Paul.V.Biron@kp.org
Sent: Thursday, February 02, 2006 3:34 PM
To: public-xsd-databinding@w3.org
Cc: public-xsd-databinding@w3.org; public-xsd-databinding-request@w3.org
Subject: Re: ISSUE-17: Advice for representing a duration

> What advice should we give for representing durations?

XML Schema 1.1 will define two totally ordered restrictions on
xs:duration: xs:yearMonthDuration and xs:dayTimeDuration [1] (following the recommendation of the Query WG) which will allay some of the fears people have in doing comparisons on xs:duration.  But, that's a 1.1 thing and xs:duration won't be deprecated, so advice is still needed for durations in general.

pvb

[1] http://www.w3.org/TR/2006/WD-xmlschema11-2-20060116/#yearMonthDuration
Received on Tuesday, 21 February 2006 15:37:48 UTC

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