About: http://webisa.webdatacommons.org/238418232

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	Sensors, such as optical sensors, not shown, may be installed to monitor the positions of the various elements.
http://www.w3.org/ns/prov#wasQuotedFrom	freepatentsonline.com