[Crm-sig] Issue 511

Robert Sanderson azaroth42 at gmail.com
Tue Mar 2 23:52:20 EET 2021


Martin wrote in particular:
  Reduce in CRMbase Mesaurement , P40 observed dimension, to E18 Physical
Thing. Add 3 different properties “has dimension” in CRMBase to E70 Thing,
E53 Place, E4 Period (or E2 Temp Entity).

I agree with your argumentation, and believe that the changes in CRM Base
would be:

P39 measured:
  Range changes from E1 CRM Entity to E18 Physical Thing

PXX1_has_dimension
  Domain: E53 Place
  Range: E54 Dimension

PXX2_has_dimension
  Domain: E4 Period
  Range: E54 Dimension

to be cognate with P43 has dimension for E70s.

The question would remain about the measuring of Non-physical Things, such
as the number of symbols in a E90 symbolic object... but I don't have that
use case, so am happy to leave the discussion to someone that does :)

Rob

On Tue, Mar 2, 2021 at 4:31 PM Martin Doerr <martin at ics.forth.gr> wrote:

>
>
> *Posted by Robert Sanderson on 9/9/2020*
>
> I believe that there is an inconsistency in the model for measurements and
> dimensions.
>
> E54 Dimensions are associated directly with E70 Things using P43 has
> dimension.  So not every class can have dimensions, only those that are
> descendents of E70.
>
> However E16 Measurement's property P39 measured has a range of E1 CRM
> Entity, meaning that while (for example) an E53 Place cannot have a
> dimension, it can be measured to have a dimension. This seems inconsistent
> that an entity that cannot have dimensions can still be measured.
>
> I propose that the range of P39 measured be changed to E70 Thing to
> resolve this inconsistency.
>
>
>
> We have to distinguish measurement from dimension. In order to measure
> something in a narrower sense, I need an observation of something material.
> Dimensions can also be result of computation, evaluation and estimation
> (forms of Attribute Assignment).
>
> If we look at measuring in the narrower sense, we can count the characters
> of a text on paper, but not the abstract text. The logical representation
> of a text can be evaluated for its dimensions.
>
> We cannot measure a place, but features at a place. See also Issue 388.
> But clearly, we can measure duration and extent of processes, and comparing
> a clock, which provides a duration from the last sync event, with some
> other transient situation or microevent, in order to calculate absolute
> time.
>
> So, we may assign the ability to be observed to E18 physical things and E4
> Period, or more narrowly to E5 Event.  The ability to be observed appears
> to need some common ontological nature, a certain materiality interacting
> with measurable signals. Even the lightning creates a plasma hose lasting
> some milliseconds. That would need a new class “Observable Entity” as range.
>
> Otherwise, we may regard measuring physical things and measuring processes *as
> independent*. Then, we would need *another measurement class*, such as
> “static measurement” versus “dynamic measurement”.
>
> Dimensions of other things, such as places in the abstract geometric sense
> of the CRM, need not be based on a common property. The place can only have
> diameters and areas as dimentions, and may be some more exotic ones. The
> dimension in the phenomenal timespan is of course that of the respective
> period etc. So, my argument being that E53 Place, E52 Time-Span have their
> own properties with range Dimension, without being regarded as observable
> (rather results of observation).
>
> I’d propose the following:
>
> Reduce in CRMbase Mesaurement , P40 observed dimension, to E18 Physical
> Thing. Add 3 different properties “has dimension” in CRMBase to E70 Thing,
> E53 Place, E4 Period (or E2 Temp Entity).
>
> Extent CRMSci by E18, E4 IsA Observable Entity, and extend Mesaurement P40
> observed dimension,  from E18 to Observable Entity.
>
> Alternatively, introduce “Dynamic Measurement”  in CRMSci.
> Best,
>
> Martin
>


-- 
Rob Sanderson
Director for Cultural Heritage Metadata
Yale University
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