Designing an Emergency Response Community for Opioid Overdoses in Philadelphia - Roy Aizen; Gabriela Marcu; Anjali Misra; Gregory Sieber; David G. Schwartz; Alexis Roth; Stephen Lankenau (Extended Abstracts of the 2018 CHI Conference on Human Factors in Computing Systems, CHI 2018, Montreal, QC, Canada, April 21-26, 2018, 2018)