Mobile Systems Researcher

I am an assistant professor at Arizona State University across the School of Electrical, Computer and Energy Engineering (ECEE) and the School of Arts, Media and Engineering (AME).

My research focuses on software and hardware systems for sensing and actuation on mobile devices. Although our devices incorporate a diverse set of informative sensors, we face the challenge of efficiently sensing, processing, and acting on data. Built on Operating Systems, Computer Architecture, and Machine Learning research, we create low-level system designs to work toward this goal.

Send me an email with your CV if you're interested in joining the lab!

[Videos of Talks]

[Educational History & Work Background]

[My surname: LiKamWa]

[Curriculum Vitae (PDF)]

Offering EEE 598: Mobile Systems Architecture in Fall '16.
Course description here.

Research Highlights

Click titles to expand

RedEye: Analog ConvNet Image Sensor Architecture for Continuous Mobile Vision

Robert LiKamWa, Yunhui Hou, Julian Gao, Mia Polansky, Lin Zhong
ACM/IEEE International Symposium on Computer Architecture (ISCA) 2016
Seoul, Korea

The RedEye vision sensor architecture extracts ConvNet features in the analog domain to reduce analog-digital sensor readout overhead. The architecture promotes focal plane scalability by localizing design complexity and promotes energy efficiency by analog noise admission.
[Paper PDF]
[Talk Slides]
[Simulation framework repository]

Starfish: Efficient Concurrency Support for Computer Vision

Robert LiKamWa, Lin Zhong
ACM Conf. on Mobile Systems, Applications, and Services (MobiSys) 2015
Florence, Italy

Starfish retrofits vision libraries for split-process execution. This allows multiple background applications to transparently share computation results through library function caching.
[Paper PDF]
[Conference Talk]
[Conference Slides PDF]

Energy Characterization and Optimization of Image Sensing Toward Continuous Mobile Vision

Robert LiKamWa, Bodhi Priyantha, Matthai Philipose, Lin Zhong, Paramvir (Victor) Bahl
ACM Conf. on Mobile Systems, Applications, and Services (MobiSys) 2013
Taipei, Taiwan
Best Paper Award

We characterize the energy consumption of image sensors to reveal opportunities for energy proportionality to tradeoff quality for power consumption. We describe simple techniques to enable such proportionality.
[Paper PDF]
[Conference Talk + 5 Minute Rundown]
[Conference Slides PDF]
[MIT Tech Review Coverage]
[Patent Application]

Building a Mood Sensor from Smartphone Usage Patterns

Robert LiKamWa, Yunxin Liu, Nicholas D. Lane, Lin Zhong
ACM Conf. on Mobile Systems, Applications, and Services (MobiSys) 2013
Taipei, Taiwan

The MoodSense/Scope project studies the use of supervised machine learning to mine inferences from smartphone usage patterns. We analyze text, call, email, location, app usage, and website browsing patterns against mood activeness and valence.
[Paper PDF]
[Conference Slides PDF]
[Conference Talk]
[Jimmy Kimmel Late Night Comedy Sketch]
[Communications of the ACM Coverage]

Reflex: Using Low-Power Processors in Smartphones Without Knowing Them

Felix Xiaozhu Lin, Zhen Wang, Robert LiKamWa, Lin Zhong
ACM Conf. on Architectural Support for Programming Languages and Operating Systems (ASPLOS) 2012
London, England

Reflex is a suite of compiler and runtime support tools for energy-efficient smartphone sensing on heterogeneous architectures. Reflex not only manages deployment and execution of code that is considered for heterogeneous resources, but also creates a software shared memory among distributed code.
[Paper PDF]
[Xiaozhu Lin's Project Site]

Other Work

(Invited Talk) Rethinking the Imaging Pipeline for Privacy-Preserving Energy-Efficient Continuous Mobile Vision

Society for Information Display (SID) Display Week 2015, San Jose, California

[Paper Link (Wiley)]
[SID Link]

(Workshop Paper) Draining our Glass: An Energy and Heat Characterization of Google Glass

APSys: Asia-Pacific Workshop on Systems 2014, Beijing, China

We teardown and analyze the Google Glass power consumption to motivate and inspire system efficiency research directions.
[Paper PDF]
[Conference Talk]

(Workshop Paper) Styrofoam: A Tightly Packed Coding Scheme for Camera-based Visible Light Communication

Visible Light Communication Systems Workshop @ MobiCom 2014, Maui, Hawaii

[Paper PDF]
[Authorship Note]

Styrofoam was authored by three Rice University Ph.D. students without their advisors, which may seem unusual to an outside observer.

Jason Holloway, David Ramirez, and I (Robert) regularly take short coffee breaks in the afternoons to clear our minds. On one such coffee break, having read one too many inspirational stories about the early days of Xerox PARC and Bell Labs, we embarked on a project that was driven more out of pure amusement and curiosity than usual. Perhaps we wanted to prove to ourselves that we could do research without external pressure. Perhaps we wanted to author a paper together while we were in the same place. Perhaps we just wanted to go to this workshop in Hawaii. I don't really remember. But in any case, we puzzled over ideas on napkins and whiteboards, and attacked a fundamental impediment of screen-camera visible light communication links: inter-symbol interference. The result was this work, Styrofoam.

We submitted without telling our advisors; if it got rejected, we were going to keep silent. However, upon acceptance, our advisors and department were very supportive in our endeavor and funded our travel, supplemented by ACM travel grants. I presented Styrofoam at the Visible Light Communication Systems workshop, while David presented the work at the ACM Student Research Competition at the main MobiCom conference, where he earned 4th place. We had a great time chatting with researchers about Styrofoam and its positioning in the Screen-Camera Link research world.

(Ph.D. Forum Talk) Efficient Image Processing for Continuous Mobile Vision

MobiSys 2014 Ph.D. Forum, Bretton Woods, New Hampshire
Best Presentation Award

[Paper PDF]

(Workshop Paper) MoodSense: Can Your Smartphone Infer Your Mood?

PhoneSense: Workshop on Sensing Applications on Mobile Phones @ SenSys 2011, Seattle, Washington
Best Paper Award

[Paper PDF]

(Demo Paper) SUAVE: Sensor-based User Aware Viewing Enhancement

UIST: ACM Symposium on User Interface Software and Technology 2011, Santa Barbara, California

Our Sensor-based User-Aware Viewing Enhancement package accounts for ambient light and viewing angle effects that impair mobile screens in many scenarios, which typically impair the quality of the display content. SUAVE uses brightness and contrast enhancements to improve mobile displays in these contextual situations, making it easier to see, read, and use mobile content.
[Paper PDF]

Miscellany

[Talks]
[Thoughts and tips on landing a faculty position (PDF)]
[Reflections of sitting on the IPSN 2015 Shadow TPC]
[Tips for Talks]
[Collaborators]
[Awards]

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