<http://webisa.webdatacommons.org/prov/156183207>	<http://www.w3.org/ns/prov#wasDerivedFrom>	<http://webisa.webdatacommons.org/289101258> .
<http://webisa.webdatacommons.org/289101258>	<http://www.w3.org/ns/prov#value>	"A light source, such as one or more light emitting diodes and a pair of light detectors, such as photodiodes, create a pair of pulse trains whose frequency varies with the speed of rotation." .
<http://webisa.webdatacommons.org/289101258>	<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>	<http://www.w3.org/ns/prov#Entity> .
<http://webisa.webdatacommons.org/289101258>	<http://www.w3.org/ns/prov#wasQuotedFrom>	<google.com> .