Observation and Measurement

The values measured by sensors are exposed as Observation and Measurement values in SENSEI. That means the values are annotated by meta-data providing additional information on how to interpret the value. Required is the data type as well as the unit of measurement. Also a time stamp is given together with the measurement. Currently there is no standard for time stamp format. Using Unix time is considered also.

An example for a light measurement is given below:

<?xml version='1.0' encoding='UTF-8'?>

<!DOCTYPE rdf:RDF [
	<!ENTITY rdf  'http://www.w3.org/1999/02/22-rdf-syntax-ns#'>
	<!ENTITY rdfs 'http://www.w3.org/2000/01/rdf-schema#'>
	<!ENTITY sensor   'http://www.ict-sensei.org/Sensor#'>
	<!ENTITY mo 'http://www.ict-sensei.org/MeasurementAndObservation#'>
	<!ENTITY provider456 'http://www.resource-provider-456.com/resources#'>
]>

<rdf:RDF xmlns:rdf="&rdf;" xmlns:rdfs="&rdfs;" xmlns:provider456="&provider456;"
	 xmlns:mo="&mo;" xmlns:sensor="&sensor;">
<sensor:Light rdf:about="&provider456;LightSensor15" 
		mo:hasTimeStamp="Thu Jan 14 09:15:36 2009"	 
		mo:hasDecimalValue="0.23"
		mo:hasUnit="percent">
</sensor:Light>
</rdf:RDF>