@techreport{TD:100823,
	att_abstract={{Knowing when and where people use greenspace is key to our understanding of urban ecology. The number of cellular phones active in a geographic area can serve as a proxy for human density in that area. We are using anonymous records of cellular network activity to study the spatiotemporal patterns of human density in an urban area. This paper presents the vision and some early results of this effort. First, we describe our dataset of six months of activity in the New York metropolitan area. Second, we present a novel technique for estimating network coverage areas. Third, we describe our approach to analyzing changes in activity volumes within those areas. Finally, we present preliminary results regarding changes in human density around Central Park. From winter to summer, we find that density increases in greenspace areas and decreases in residential areas.}},
	att_authors={rc177e, jr6321, su2464},
	att_categories={C_NSS.7, C_NSS.18, C_IIS.2},
	att_copyright={{Springer}},
	att_copyright_notice={{The definitive version was published in 2012 {{, 2012-06-19}}
}},
	att_donotupload={},
	att_private={false},
	att_projects={ SagaCITY},
	att_tags={},
	att_techdoc={true},
	att_techdoc_key={TD:100823},
	att_url={http://web1.research.att.com:81/techdocs_downloads/TD:100823_DS1_2012-06-20T11:46:30.524Z.pdf},
	author={Ramon Caceres and James Rowland and Christopher Small and Simon Urbanek},
	institution={{2nd Workshop on Pervasive Urban Applications (PURBA)}},
	month={June},
	title={{Exploring the Use of Urban Greenspace through Cellular Network Activity}},
	year=2012,
}