A power transmitting assembly having a differential case and a differential gearset that is received in an interior chamber in the differential case. 1 dBcm is achievable at optical communications wavelengths, with even lower values being possible. The fuel element is adapted to prevent improper insertion of the wick holder into the duct. Unlike with laser rangefinders, the visual techniques are economically practical in a wide range of applications and can be used in relatively dynamic environments, such as environments in which people move. To allow unambiguous classification, the data model comprises a property definition including at least one property name, at least one property value and at least one process value for storing at least one process identifier identifying processes assigned to the property.