SysML 2.0b2 FTF Avatar
  1. OMG Issue

SYSML2 — Extend ISQ with missing quantity and unit types for US Customary Units

  • Key: SYSML2-82
  • Status: open  
  • Source: Model Driven Solutions ( Mr. Ed Seidewitz)
  • Summary:

    The US Customary Units as specified in NIST SP811 Annex B include a number of units for which the corresponding quantity is not defined in ISO/IEC 80000, the International System of Quantities (ISQ). These units are currently commented out in Quantities and Units Domain Library USCustomaryUnits. Examples are:

    //attribute <'Btu_IT/ft³'> 'British thermal unit (IT) per cubic foot' : EnergyDensityUnit = Btu_IT/ft^3;
    //attribute <'gal/(hp⋅h)'> 'gallon (US) per horsepower hour' : EnergySpecificVolumeUnit = gal/(hp*h);
    //attribute <'mi/gal'> 'mile per gallon (US)' : FuelEconomyUnit = mi/gal;
    //attribute <'lb/(hp⋅h)'> 'pound per horsepower hour' : FuelConsumptionUnit = lb/(hp*h);

    An additional extension package for ISQ is needed that declares the attribute definitions for the missing quantity and measurement unit types, e.g.:

    • EnergyDensityValue and EnergyDensityUnit
    • EnergySpecificVolumeValue and EnergySpecificVolumeUnit
    • FuelEconomyValue and FuelEconomyUnit
    • FuelConsumptionValue and FuelConsumptionUnit

    It should be considered whether or not to include the new library package inside ISQ, as formally these quantity and unit types are not part of ISO/IEC 800000.

  • Reported: SysML 2.0a1 — Thu, 27 Apr 2023 21:14 GMT
  • Updated: Wed, 10 Apr 2024 00:41 GMT