Use Case 5: Find devices associated with certain real-world properties.

The user wants to know what instruments can measure a given environmental property, for example conductivity (for example, to obtain an instrument to perform the measurement, or to analyze those instruments for some other purpose). 

In this case the important concept is not what variables are ultimately produced, but what measurements are directly sensed. That is the primary distinction from Use Case 4.

Note the relationship (but not equivalence) to Use Case 8, which focuses on the sensors rather than the device as a unit.

There is another use case, Use Case 12, which is almost the inverse of this use case. It involves using the variable terms to produce higher-level documentation of an instrument.

A scientist wants to buy equipment to study a particular phenomenon, and wants to find ALL the instruments that are capable of studying that phenomenon (not just those discoverable through manual or on-line searches through catalogs, or through Google entry of a keyword).

The user workflow is:
1.  User enters phenomena of interest into search tool.
2.  Search tool derives parameters of interest to study that phenomenon. 
3.  (Search tool may present parameters list for user confirmation/edit.)
4.  Search tool returns a list of instruments associated with those parameters, including links to manufacturer's on-line catalogue.

The developer workflow is:
1.  Parameters in ontology are mapped into a vocabulary of observed phenomena.
2.  Parameters in ontology are mapped into a list of instrument types.
3.  Add inferencing to tool to get from observed phenomena to parameters,
    and parameters to instruments.
4.  Execute geospatialtemporal and other filters as appropriate to 
    obtain only instruments of interest.
5.  Return instrument list.