Hendrik Lemelson Thomas King Wolfgang Effelsberg Pre-processing of fingerprints to improve the positioning accuracy of 802.11-based positioning systems. 73-78 2008 MELT http://doi.acm.org/10.1145/1410012.1410029 conf/mobicom/2008melt db/conf/mobicom/melt2008.html#LemelsonKE08