qudt an owl ontology for q uantities , u nits, d imensions and data t ypes
DESCRIPTION
QUDT An OWL Ontology for Q uantities , U nits, D imensions and Data T ypes. Han Wang April 3 rd , 2013. Introduction. Developed by TopQuadrant and NASA for NASA Exploration Initiatives Ontology Models ( NExIOM ) project. - PowerPoint PPT PresentationTRANSCRIPT
QUDTAn OWL Ontology for
Quantities, Units, Dimensions and Data Types
Han WangApril 3rd, 2013
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Introduction
• Developed by TopQuadrant and NASA for NASA Exploration Initiatives Ontology Models (NExIOM) project.
• A unified model of physical quantities, units of measure, and their dimensions in various measurement systems.
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Classes – cont’d
• Quantity– An observable property of an object, event or
system that can be measured and quantified numerically.
– Differentiated by two attributes: quantityKind and quantityValue.
– If two quantities are of the same kind, their magnitudes (values) can be compared and ordered.
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Classes – cont’d
• QuantityKind– Any observable property that can be
measured and quantified numerically.– E.g. length, mass, currency, interest rate, etc.
• QuantityValue– The numerical value of a quantity with
respect to a chosen unit of measure.
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Classes – cont’d
• Unit– A particular quantity of a given kind that has
been chosen as a scale for measuring other quantities of the same kind.
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Classes – cont’d
• SystemOfQuantities– A set of one or more quantity kinds together
with a set of zero or more algebraic equations that define relationships between quantity kinds in the set.
– E.g. SI system, CGS system– Base quantity kinds (e.g. length, mass, time)– Derived quantity kinds (e.g. area, force,
power)
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Classes – cont’d
• SystemOfUnits– A set of units which are chosen as the
reference scales for some set of quantity kinds together with the definitions of each unit.
– Base units (e.g. meter, kilogram, second)– Derived units (e.g. square meter, newton,
watt)
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Classes – cont’d
• Dimension– a mapping from a tuple of rational numbers
to a product of base quantity kinds such that the tuple members correspond to the exponents of the base quantity kinds.
– E.g. A = L2, F = L1M1T-2, P = L2M1T-3
– dim Q = (B1)d1(B2)d2…(Bn)dn
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Examples
• Value of Planck’s Constant in SI and CGS Units
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Examples – cont’d
• Dimensions for Permittivity
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Applications: SPIN Functions
• Unit conversion
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Applications: SPIN Functions – cont’d
• Unit conversion
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Conclusion
• A straightforward model for representing physical quantities.
• Capable of rule-based inference.• Not so much on metadata of the
quantities.
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References
• http://qudt.org/• http://ontolog.cim3.net/file/work/UoM/
UoM-standard-ontology_20090924/QUDT-overview--JamesMasters_20090924.pdf
• http://linkedmodel.org/catalog/qudt/1.1/
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