Some scoping questions, that might be obvious or might help clarify the discussion…
The National Fire Protection Association is responsible for the safety diamond, that has Health (blue), Flammable (red) and Reactivity (yellow) ratings for the sample or area, each of which is measured from 0-4. This seems like a quantified numeric value with a particular unit. Is that then a Dimension, like:
_:x a Dimension ;
P2_has_type <health safety> ;
P90_has_value 3 ;
P91_has_unit <nfpa_unit> .
Color can be measured, but to be useful has three component parts. Pure red could be expressed as 256 red, 0 green, 0 blue. A type of redness, a value of 256, and a unit of hexademical color proportion (e.g. as per https://www.w3.org/TR/2018/REC-css-color-3-20180619/#rgb-color or the standard for sRGB)
This would be most usefully expressed as a partitioning of an overall color dimension. This would be a second example of dimension partitioning to go along with non decimal unit systems (feet and inches, etc.) or currencies (florins, etc).
Here my homework!
The sig discussed Martin's proposal about the relaxation of definition of E54 to either representing the approximation of a true quantity of a thing or phenomenon provided by a measurement or a derived quantity computed indirectly from observation data comparable to reality, or a quantity produced by simulation of reality-like situations.
Some comments are:
· the phrase "An instance of E54 Dimension is specific to an instance of E70 Thing" in the scope note of P43 is too specific and it is not compatible with the above approach. There are some consequences of this approach.
· We should consider the properties of a physical thing.
A conclusion was that closeness or overlap of given bounds of approximation are the means to reason on the compatibility with a common reality or item. Arrays and time series are regarded as “complex” dimensions.
The SIG assigned to MD to rewrite the scope note of E54.
Here it is, a bit lengthy I admit:
Subclass of: CRM Entity
Scope note: This class comprises quantifiable properties of things or phenomena that can be measured by some calibrated means and can be approximated by values, i.e. points or regions in a mathematical or conceptual space, such as natural or real numbers, RGB values etc.
An instance of E54 Dimension may represent either the result of a measurement of a quantity of some things or phenomena, or the result of an evaluation of observation data indirectly determining an approximation of such a quantity, or the result of a prediction or hypothetical simulation of such a quantity in a scenario of a possible or alternative evolution of reality. Quantifiable properties of conceptual objects are observed on representative carriers. Not only dimensions of persistent items can be quantifiable, but also durations, spatial and temporal distances of instances of E2 Temporal Entities.
Most quantifiable properties change over time and have a continuous value space. Therefore, multiple observations will differ from each other, but knowledge about the precision of the respective determination method and domain knowledge about the changes to be expected between observations allow for reasoning which results of multiple observations are compatible with a common reality and can be used for further approximating the real quantities. For instance the weight of a person varies in the course of the day in a kg range. Wood expands under humidity some per cents, metal much less under increasing temperature. Instances of E54 Dimensions are specific to the way a property is determined. For instance, the length of a museum objects determined by the smallest rectangular bounding box is different from the maximum length of the object.
The properties of the class E54 Dimension allow for expressing the numerical approximation of the values of an instance of E54 Dimension. If the true values belong to a non-discrete space, such as spatial distances, it is recommended to record them as approximations by intervals or regions of indeterminacy enclosing the assumed true values. For instance, a length of 5 cm may be recorded as 4.5-5.5 cm, according to the precision of the respective observation. Note, that interoperability of values described in different units depends critically on the representation as value regions. For instance, 5cm is about 1.96850394 inches. 2 inches on the other side may be interpreted as something between 1.5-2.5 inches, which would be something within 3.5-6.5 cm.
Numerical approximations in archaic instances of E58 Measurement Unit used in historical records should be preserved. Equivalents corresponding to current knowledge should be recorded as additional instances of E54 Dimension as appropriate.
§ The 250 metric ton weight of the Luxor Obelisk
§ The 5.17 m height of the statue of David by Michaelangelo
§ The 530.2 carats of the Great Star of Africa diamond
§ The AD1262-1312, 1303-1384 calibrated C14 date for the Shroud of Turin
§ The 33 m diameter of the Stonehenge Sarcen Circle
§ The 755.9 foot length of the sides of the Great Pyramid at Giza
§ Christies’ hammer price for “Vase with Fifteen Sunflowers” (E97) has currency British Pounds (E98)
Dr. Martin Doerr
Honorary Head of the
Center for Cultural Informatics
Information Systems Laboratory
Institute of Computer Science
Foundation for Research and Technology - Hellas (FORTH)
N.Plastira 100, Vassilika Vouton,