Sentence:  Philadelphia's foot-<WSD>patrol</WSD> strategy was developed after a study in 2009 by criminologists from Temple University, which is in the 22nd district. A randomised trial overturned the conventional view that foot <WSD>patrols</WSD> make locals like the police more and fear crime less, but do not actually reduce crime. In targeted areas, violent crime decreased by 23%. 
Meaning of the word marked with <WSD> tags:  Any perambulation of a particular line or district to guard it; also, the people thus guarding.