I am a 1st year PhD Student in the Computer Science Department at Dartmouth College. I am currently working in the DartNets Lab under the supervision of Prof. Xia Zhou.

My primary research interests are mobile system and wireless networking. Much of my recent work is in visibile light communication (VLC) system. The goal is to tackle some fundamental challenges on VLC system design and implementation. I also explore VLC system applications in communication, sensing, and HCI. I am broadly interested in machine learning and mobile sensing.

I earned my M.S. at Dartmouth College in 2014 and B.E. with honor from Australian National University in 2012.


Publications

*H-index = 3, Citation = 59 according to Google Scholar.

Conference and Workshop

  • Human Sensing Using Visible Light Communication
    Tianxing Li, Chuankai An, Zhao Tian, Andrew T. Campbell, and Xia Zhou,
    Proceedings of The 21st Annual International Conference on Mobile Computing and Networking (MobiCom)
    Paris, France, Sept. 2015.
    PDF coming soon

  • Visible Light Knows Who You Are
    Chuankai An, Tianxing Li, Zhao Tian, Andrew T. Campbell, and Xia Zhou,
    Proceedings of The 2nd ACM Workshop on VLC systems (VLCS)
    Paris, France, Sept. 2015.
    PDF coming soon

  • Low-Power Pervasive Wi-Fi Connectivity Using WiScan
    Tianxing Li, Chuankai An, Ranveer Chandra, Andrew T. Campbell, and Xia Zhou,
    Proceedings of the 2015 ACM International Joint Conference on Pervasive and Ubiquitous Computing (UbiComp)
    Osaka, Japan, Sept. 2015.
    PDF coming soon

  • Real-time Screen-camera Communication Behind Any Scene
    Tianxing Li, Chuankai An, Xinran Xiao, Andrew T. Campbell, and Xia Zhou,
    Proceedings of The 13th International Conference on Mobile Systems, Applications, and Services (MobiSys)
    Florence, Italy, May 2015.
    PDF

  • HiLight: Hiding Bits In Pixel Translucency Changes
    Tianxing Li, Chuankai An, Andrew T. Campbell, and Xia Zhou,
    Proceedings of The 1st ACM Workshop on VLC systems (VLCS)
    Maui, Hawaii, Sept. 2014.
    PDF  Best Paper Award

  • StudentLife: Assessing Mental Health, Academic Performance And Behavioral Trends Of College Students Using Smartphones
    Rui Wang, Fanglin Chen, Zhenyu Chen, Tianxing Li, Gabriella Harari, Stefanie Tigno, Xia Zhou, Dror Ben-Zeev, and Andrew T. Campbell,
    Proceedings of the 2014 ACM International Joint Conference on Pervasive and Ubiquitous Computing (UbiComp)
    Seattle, Sept. 2014.
    PDF  Best Paper Nominee

  • Unobtrusive Sleep Monitoring Using Smartphones
    Zhenyu Chen, Mu Lin, Fanglin Chen, Lane, N.D., Cardone, G.,Rui Wang, Tianxing Li, Yiqiang Chen, Choudhury, T. Campbell, A.T.,
    Proceedings of The 7th International Conference on Pervasive Computing Technologies for Healthcare (Pervasive Health)
    Venice, Italy, May 2013.
    PDF

  • Dual Deblurring Leveraged By Image Matching
    Fang Wang, Tianxing Li, Yi Li,
    Proceedings of the 2013 IEEE International Conference on Image Processing (ICIP)
    Melbourne, Australia, Sept. 2013.
    PDF

  • Demos and Posters

    • Demo: Real-Time Screen-Camera Communication Behind Any Scene
      Tianxing Li, Chuankai An, Xinran Xiao, Andrew T. Campbell, and Xia Zhou,
      Proceedings of The 13th International Conference on Mobile Systems, Applications, and Services (MobiSys)
      Florence, Italy, May 2015.
      PDF  Best Demo Award

    • Poster: HiLight: Hiding Bits In Pixel Translucency Changes
      Tianxing Li, Chuankai An, Andrew T. Campbell, and Xia Zhou,
      Proceedings of The 20st Annual International Conference on Mobile Computing and Networking (MobiCom)
      Maui, Hawaii, Sept. 2014.
      PDF  Student Research Competition Bronze Medal


    • Research

      LiSense

      Human Sensing Using VLC

        LiSense is the first-of-kind system that enables both data communication and fine-grained, real-time human skeleton reconstruction using Visible Light Communication. LiSense uses shadows created by the human body from blocked light and reconstructs 3D human skeleton postures in real time. Multiple lights on the ceiling lead to diminished and complex shadow patterns on the floor. We design light beacons to separate light rays from different light sources and recover the shadow pattern cast by each individual light. Then, we design an efficient inference algorithm to reconstruct user postures using 2D shadow with a limited resolution collected by photodiodes. This work will be presented in MobiCom'15.

        LiSense reconstructs the 3D user skeleton at 60 Hz in real time with 10° mean angular error for five body joints.

      WiScan

      Low-Power Pervasive Wi-Fi Connectivity

        Pervasive Wi-Fi connectivity is attractive for users in places not covered by cellular services (e.g., when traveling abroad). However, the power drain of frequent Wi-Fi scans undermines the device's battery life, preventing users from staying always connected and fetching synced emails and instant message notifications. We study the energy overhead of scan and roaming in detail and refer to it as the scan tax problem. Our findings show that the main processor is the primary culprit of the energy overhead. We design and build WiScan to fully exploit the gain of scan offloading. This work will be presented in UbiComp'15.

        WiScan achieves 90%+ of the maximal connectivity, while saving 50-62% energy for seeking connectivity.

      HiLight

      Real-Time Screen-Camera Communication Behind Any Scene

        HiLight is a new form of real-time screen-camera communication without showing any coded images (e.g., barcodes) for off-the-shelf smart devices. HiLight encodes data into pixel translucency change atop any screen content, so that camera-equipped devices can fetch the data by turning their cameras to the screen. HiLight leverages the alpha channel, a well-known concept in computer graphics, to encode bits into the pixel translucency change. By removing the need to directly modify pixel RGB values, HiLight overcomes the key bottleneck of existing designs and enables real-time unobtrusive communication while supporting any screen content. This work was presented in MobiSys'15 and won the Best Demo Award. [PDF][CODE][PROJECT WEBSITE]

        We design and build HiLight using off-the-shelf smart devices, the first system that realizes on-demand data transmissions in real time unobtrusively atop arbitrary screen content.

      StudentLife

      Assessing Mental Health, Academic Performance and Behavioral Trends of College Students using Smartphones

        The StudentLife continuous sensing app assesses the day-today and week-by-week impact of workload on stress, sleep, activity, mood, sociability, mental well-being and academic performance of a single class of 48 students across a 10 week term at Dartmouth College using Android phones. This work was presented in UbiComp'14. [PDF][PROJECT WEBSITE]

        The StudentLife study shows a number of significant correlations between the automatic objective sensor data from smartphones and mental health and educational outcomes of the student body.