MOBILE COMPUTING & COMMUNICATIONS REVIEW Volume 21, Issue 4 • December 2017 GetMobile

IoT PLATFORMS FOR SPORTS ANALYTICS Page 8 A PUBLICATION OF ACM SIGMOBILE GetMobile MOBILE COMPUTING & COMMUNICATIONS REVIEW

Volume 21, Issue 4 • December 2017 CONTENTS

3 Message from the Editor-in-Chief HIGHLIGHTS 16 Card-Stunt as a Service: Empowering a Massively Packed Crowd for Instant Collective Expressiveness

22 DroneTrack: An Indoor Follow-Me 15 System Using Acoustic Signals 25 BackDoor: Sounds that a Microphone AWARDS Can Record, but That Humans 15 2017 SIGMOBILE Can’t Hear Outstanding Contributions Award: 30 Cost-Effective and Passive RF-Based Norman Abramson Drone Presence Detection and Characterization 5 25 EXPERIMENTAL METHODS 5 Understanding and Assessing the User Burden of Mobile Apps

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(ALMOST) UNPUBLISHABLE RESULTS 30 8 IoT Platforms for Sports Analytics

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2 GetMobile December 2017 | Volume 21, Issue 4 MESSAGE FROM THE EDITOR-IN-CHIEF

CONTRIBUTORS

EDITOR-IN-CHIEF IN THIS ISSUE, we introduce a new Awards Eyal de Lara, University of Toronto column. With Robert LiKamWa from Arizona MANAGING EDITOR Donna Paris State University as its inaugural editor, this DESIGNER JoAnn McHardy column showcases the top recognitions SENIOR ADVISORS (Past Editors-in-Chief) bestowed by ACM SIGMOBILE. The first Paramvir Bahl, Microsoft Research Awards column features Dr. Norman Suman Banerjee, University of Wisconsin, Madison Srikanth Krishnamurthy, University of , Abramson, who received the 2017 SIGMOBILE Riverside Outstanding Contributions Award for Jason Redi, BBN Technologies “fundamental contributions to the theory and Mani Srivastava, University of California, Los Angeles practice of random access wireless networking.” Nitin Vaidya, University of Illinois, Urbana-Champaign Eyal de Lara This issue highlights four papers from SECTION EDITORS ACM MobiSys 2017. “Card-Stunt as a Service: Empowering a Massively Ardalan Amiri Sami, University of California, Irvine Aruna Balasubramanian, Stony Brook University Packed Crowd for Instant Collective Expressiveness,” by Chungkuk Nilanjan Banerjee, University of Maryland, Yoo, Inseok Hwang, Seungwoo Kang, Myung-Chul Kim, Seonghoon Baltimore County Kim, Daeyoung Won, Yu Gu, and Junehwa Song describes a system that Geoffrey Challen, University at Buffalo makes it possible for a crowd to create a massive collective visualization Romit Roy Choudhury, University of Illinois, Urbana-Champaign using their . Their approach uses visible-light sensing to Prabal Dutta, University of Michigan localize individuals in the crowd without using any infrastructure. Carla S. Ellis, Duke University In “DroneTrack: An Indoor Follow-Me System Using Acoustic Michelle X. Gong, Signals,” Wenguang Mao and Lili Qiu describe a drone that supports Marco Gruteser, Rutgers University Haitham Hassanieh, University of Illinois, indoor follow-me functions for high-quality videotaping. In their Urbana-Champaign approach, the drone maintains a fixed distance from the subject being Julie A. Kientz, University of Washington videotaped by decoding acoustic signals emitted by Nic Lane, Bell Labs and University College, a app running on the mobile carried by the subject. Robert LiKamWa, Arizona State University In “BackDoor: Sounds That a Microphone Can Record, but That Shiwen Mao, Auburn University Iqbal Mohomed, Samsung Research America Humans Can’t Hear,” Nirupam Roy, Haitham Hassanieh and Romit Sami Rollins, University of San Francisco Roy Choudhury show that carefully designed ultrasound signals can be Lin Zhong, Rice University recorded by unmodified off-the-shelf microphones, while remaining Xia Zhou, Dartmouth College inaudible to humans. The approach makes possible a range of new ACM STAFF applications, including inaudible data communication, spy microphone Julie Goetz, Administrator – Publications Production Adrienne Griscti, Program Coordinator – SIG Publications jamming, and acoustic watermarking. Fran Spinola, Program Coordinator – SIG Activities Lastly, in “Cost-Effective and Passive RF-based Drone Presence SIGMOBILE EXECUTIVE COMMITTEE Detection and Characterization,” Phuc Nguyen, Hoang Truong, Mahesh Suman Banerjee, University of Wisconsin-Madison, Chair Ravindranathan, Anh Nguyen, Richard Han and Tam Vu describe Lili Qiu, University of Texas Austin, Vice Chair a passive sensing approach that detects the presence of a drone by Marco Gruteser, Rutgers University, Treasurer Alec Wolman, Microsoft Research, Secretary identifying the unique signatures of its body vibration and body shifting

Cover photo, istockphoto.com istockphoto.com photo, Cover Roy Want, Google, Past Chair in the transmitted wireless signals.

December 2017 | Volume 21, Issue 4 GetMobile 3 EDITORIAL CORRESPONDENCE Address to: Prof. Eyal de Lara, 40 St. George Street, Suite 4283, Department of Computer Science, University of Toronto, Toronto, Ontario M5S2E4, The rest of the issue consists of two Finally, the (Almost) Unpublishable Canada, Email: [email protected]. For specific department email addresses, see the more columns: Results column features an article by “Call for Contributions” on page 59. In the Experimental Methods Mahanth Gowda, Ashutosh Dhekne, column, Julie A. Kientz and Hyewon Sheng Shen, Romit Roy Choudhury, NOTICE TO CONTRIBUTING Suh argue that mobile app designers Sharon Xue Yang, Lei Yang, Suresh AUTHORS TO SIG NEWSLETTERS should look beyond traditional metrics Golwalkar, and Alexander Essanian By submitting your article for distribution in this Special Interest Group publication, you hereby for evaluating user experience, such as that reports on their experience grant to ACM the following non-exclusive, usability, look and feel, usefulness, and developing IoT platforms for sports perpetual, worldwide rights: to publish in print overall delight that users experience, analytics in general, and the sport of on condition of acceptance by the editor, to digitize and post your article in the electronic and focus instead on the overall cricket in particular. Their system, version of this publication, to include the burden that the application places on iBall, embeds sensors inside cricket article in the ACM Digital Library, and to the user. For example, a game may be balls to track a ball’s 3D trajectory allow users to copy and distribute the article for noncommercial, educational or research irresistibly engaging, but also make and spin. iBall performs the fusion of purposes. However, as a contributing author, users feel guilty about how much time wireless and inertial sensory data and you retain copyright to your article and ACM they spend with it, or a fitness tracker integrates it into physics-based motion will make every effort to refer requests designed to help people be more active models of a ball in flight. for commercial use directly to you. only serves to make them feel badly I hope you enjoy this issue, and I ACM GETMOBILE about themselves for not exercising welcome your thoughts about GetMobile ACM SIGMOBILE publishes ACM GetMobile after sustaining an injury. in general, and this issue in particular. n four times annually for its members. The Newsletter has a controlled distribution with the compliments of ACM SIGMOBILE. GetMobile assumes no responsibility for the return of submitted manuscripts, photographs, artwork, Editorial Board Changes or other material. Nothing in this publication It is my pleasure to welcome Robert LiKamWa as the inaugural editor of the Awards shall constitute an endorsement by ACM, or column. Robert is an assistant professor at Arizona State University in the School of SIGMOBILE or GetMobile (collectively, the “Publisher”) of any information contained in Arts, Media and Engineering (AME) and the School of Electrical, Computer and Energy this publication, and the Publisher declaims Engineering (ECEE). He heads Meteor Studio (towards Mobile any liability with respect thereto or the use or Experiential Technologies through Embedded Optimization reliance on any such information. The infor- Research), which designs novel software and hardware systems mation contained in the publication is in no to raise the performance, efficiency, and expressiveness of way to be construed as a recommendation by the Publisher of any kind or nature whatsoever, smartphones, tablets, VR/AR devices, and other mobile nor as a recommendation of any industry systems. He completed his BS, MS, and PhD degrees at Rice standard, nor as an endorsement of any product University in the Department of Electrical and Computer or service, nor as an opinion or certification Engineering. He has also interned at Microsoft Research in regarding the accuracy of any such information. Redmond, Washington and in Beijing, China, and Samsung SIGMOBILE URL: Mobile Processor Innovation Lab in Richardson, Texas. http://www.acm.org/sigmobile Robert LiKamWa ISSN 2375-0529

4 GetMobile December 2017 | Volume 21, Issue 4