Warning: This repository is intrinsic unstable.
We are facing two not compatible aims. On one side, in order to actually use EMMO, datatypes and units are essential. On the other side, since there has been put so much effort into EMMO, we cannot allow to introduce new concepts that are not well thought through and tested.
The aim of this repository is to allow testing out new ideas about datatypes and units in domain and application ontologies. The hope is that this the content soon will be merged into EMMO.
emmo-units is based on the upstream v1.0.0 development branch of EMMO.
| file | description |
|---|---|
| emmo-units.owl | Toplevel unit ontology that imports the rest |
| emmo/ | Git submodule with upstream EMMO |
| base/emmo-annotations.owl | Additional annotations introduced in emmo-units |
| domain/emmo-datatypes.owl | Basic data types |
| domain/emmo-units.owl | Unit basic (to be included in EMMO core) |
| domain/emmo-si-units.owl | Realisation of SI units |
| domain/emmo-physical-constants.owl | Realisation physical constants |
| domain/emmo-physical-dimensions.owl | Realisation physical constants |
Adds two object annotations; iupacDoi and qudtSameAs under rdfs:seeAlso. They are used to provide a doi to a human readable definitions in IUPAC and the corresponding concept in QUDT (with information about e.g. unit conversions), respectively. Maybe iupacDoi should be placed under rdfs:isDefinedBy instead. They can probably also be named better. They are currently only used in emmo-si-units.owl and emmo-physical-constants.owl, but could be used more widely in EMMO.
This is an early draft for formalising data types and dimensionality. A very interesting extension is to add data representations (in a separate owl file) so that we have a common way to express how a quantity is represented in an applications, like whether it is a single number, a field, probability distribution, etc...
Defines the basic categorisation for physical quantities and units, but does not define any unit or quantity itself.
Adds a set of common SI units and corresponding physical quantities. It is essentially based on the first table on https://en.wikipedia.org/wiki/SI_derived_unit. Common derived units without an own name, like square metre, Newton second, etc are still missing. Likewise a limited set of common Physical constants are not yet included.
It adds also a DimensionalQuantity branch with two subbranches,
VectorQuantity (rank 1) and MultiDimensionalQuantity (rank 2 or larger).
Adds physical constants. The qudtSameAs annotation is used to refer to the CODATA 2018 value (effectuated May 20, 2019).
Defines and apply cardinality restrictions for specifying the physical dimensionality of derived physical quantities in terms of base and dimensionalless quantities.
Note that domains/emmo-physical-dimensions.owl is not loaded by default since the cardinality restrictions makes the reasoner extremely(!) slow.
Since the cardinality restrictions defined in domains/emmo-physical-dimensions.owl makes the reasoner extremely slow, domains/emmo-physical-dimensions.owl is not loaded by default. To work with a reasoned ontology include these restrictions, do as follows:
- Load emmo-units.owl in the root directory
- Run the FaCT++ reasoner
- Load domains/emmo-physical-dimensions.owl into the existing ontology
- Run the FaCT++ reasoner again
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Should physical quantities be moved to its own owl file?
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Are dimensional quantities constructed the right way, using cardinality for vector quantities (rank 1) and a linked list of QuantityDimension classes for multi-dimensional quantities?
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Referring concepts in EMMO to corresponding concepts in other widely accepted resources seems to be a good idea. We have here introduced dedicated annotation properties for referring to IUPAC DOIs and QUDT URIs. Sub-questions:
- Are the names iupacDoi and qudtSameAs well chosen?
- Is it a problem that the URLs to the CODATA definitions of physical constants in QUDT are dead links? For example is Avogagro constant referred to as https://physics.nist.gov/cuu/CODATA-Value_AvogadroConstant (dead) in http://data.qudt.org/qudt/owl/1.0.0/nist-constants.owl.
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Should the categorisation of physical quantities (incl. compound quantities, dimensional quantities and physical constants) be kept in emmo-units.owl? Alternatively could e.g. PhysicalConstant be moved to domain/emmo-physical-constant.owl.