Unit
This ontology represents the different units of measurement in universAAL, such as units or dimensions. Since this is a common concept that can be used by any other extending ontology, it is considered part of the Upper Ontology.
A Service ontology concept (UnitService) is in place for implementations to provide unit conversion services. It has a "controls" property on the Unit concept.
- Unit
- Ontological representation of a unit of measurement. Units from a certain UnitSystem have a name (e.g., meter), are used for measuring a certain dimension (e.g., LENGTH), and a certain symbol might be used to refer to them (e.g., m). Non-basic units can be calculated based on basic units using a formula ⇒ basic units will have no calculation formula.
- UnitSystem
- The class representing a unit system. According to Wikipedia, "The most widely used system of units is the International System of Units, or SI." A UnitSystem consists of several systemUnits, which are instances of Unit.
- Dimension
- An open enumeration of all dimensions for which there is a measurement unit in some UnitSystem.
- UnitPrefix
- e.g., kilo (factor 1000, symbol k), hecto (factor 100, symbol h), deka (factor 10, symbol da), deci (factor 0.1, symbol d), centi (factor 0.01, symbol c), milli (factor 0.001, symbol m), ...