<unitList>

1
ltunitListgtlt/unitListgt

• LTER Information Managers Meeting
• Montreal, Canada
• 4-7 August 2005
• Mark Servilla (LNO)

2
System Internationale

• Base Units - Quantity versus Unit
• Quantity is the amount that is being measured
• Unit is a determinate quantity adopted as a
  standard of measurement

3
SI cont.

• Derived Units
• formed as products of powers of the base units
  according to the algebraic relations linking the
  quantities concerned
• Examples
• Speed metersPerSecond m/s
• Acceleration metersPerSecondSquared m/s2
• Volumetric Rate cubicMetersPerSecond m3/s

4
STMML

• Scientific, Technical, Medical Markup Language
• ltunitListgt
• ltunitTypegt
• ltunitgt
• Example
• ltunitListgt
• ltunitType id"volumetricRate" name"volumetricRate
  "gt
• lt!-- EML-2.0.1 --gt
• ltdimension name"meter" power"3"/gt
• ltdimension name"second" power"-1"/gt
• lt/unitTypegt
• ltunit id"cubicMetersPerSecond"
  abbreviation"m³/s" name"cubicMetersPerSecond"
  unitType"volumetricRate"gt
• lt!-- LNO-LTER --gt
• ltdescriptiongt
• cubic meters per second
• lt/descriptiongt
• lt/unitgt
• lt/unitListgt

5
STMML Schema
6
STMML Rules

• There exist 7 base SI units
• Derived SI units can be formed by any combination
  of products of powers of the base units
• SI units cannot have a "parent SI" unit
• SI units cannot have a "multiplier" or "constant"
  to derive another SI unit
• Non-SI units must have a relationship to an SI
  unit, and this SI unit is defined as the "parent
  SI" unit
• Non-SI units must have a scalar quantity, the
  "multiplier", that can be used to convert the
  non-SI unit quantity to the SI unit quantity
• Non-SI units may have a scalar quantity, the
  "constant", that can be added to the non-SI unit
  (in combination with the "multiplier") to convert
  the non-SI unit quantity to the SI unit quantity

7
Beyond theeml-unitDictionary

• Current limitations
• Error correction
• Extensibility
• Future directions
• dictionaries and registries
• LTER Custom Unit Registry Project
• LSID (Life Sciences IDentifier)
• urnlsidlternet.eduu4322
• Ontologies (as related to Attributes)