About: http://webisa.webdatacommons.org/146206827

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	Note that while an audible acoustic signal (beep) is used as one example herein, it is alternatively feasible to use other types of signals, such as ultrasonic, supersonic and/or subsonic frequencies, alone or in any combination.
http://www.w3.org/ns/prov#wasQuotedFrom	google.com