About

I am a Ph. D. student in Artifical Intelligence, in the Department of Computer Science at the University of California at Berkeley.

My advisors are Pieter Abbeel and Alexandre Bayen.

Degrees:

M.Sc. Electrical Engineering,
Stanford University, 2008
Eng. Deg., Applied Math.
Ecole Polytechnique, France, 2004

Research interests:

Artificial intelligence
- Bayesian inference on large scale systems
- Reinforcement learning
Distribution software engineering
- Optmization
- Cloud-based machine learning
Privacy and security in cyberphysical systems
- Information sharing
- Transportation in intelligent infrastructure systems

Contact

E Mail: tjhunter@eecs.berkeley.edu

Address:

Timothy Hunter
University of California, Berkeley
710 Sutardja Dai Hall
Berkeley, CA 94720-1720

Social networks: I am also on LinkedIn and Viadeo.

CV: PDF Shorter version

Research

I work on the Mobile Millennium project, and its successor, the Integrated Corridor Management (ICM) project. The Mobile Millennium project aims to develop methodologies and algorithms in traffic estimation, traffic forecast and real-time routing. It is a joint effort between UC Berkeley, the California Department of Transportation, Navteq and Nokia.

In this context I am interested in efficient statistical methods for estimating traffic. In particular, I work on correctly mapping probe data to the road network, and on distributed algorthims using cloud computing. This is a joint research project with the AMPLab at UC Berkeley.

Here are a few projects I have been working on.

Path inference

The Path Inference Filter (PIF) is a novel algorithm to map-match GPS trajectories on a road network. It works on GPS data sampled at high frequencies (1Hz) or low frequencies (up to 2 minute intervals) and can be adapted to a variety of scenarios (offline smoothing, online filtering, etc.). We use it in the Mobile Millennium project to map several millions of GPS points from various sources on a daily basis. We provide an implementation in Scala/Java that can map several thousands points per second on a road network comprising 2 millions road elements with high accuracy (the San Francisco Bay Area).

A nearly industrial-grade implementation (Scala) is available at https://github.com/calpath/open-traffic

A more academic (slower) implementation in Python is available at https://github.com/tjhunter/Path-Inference-Filter

More code, videos, examples are available here.

Large scale estimation

(Joint work with Matei Zaharia and Tathagata Das) We investigated solving traffic estimation at a very large scale using the Spark computing framework. We implemented an EM algorithm that can update traffic estimates in less than 5 seconds from a GPS stream with a rate of tens of thousands of observations per second (using a cluster of 80 machines).

See references [4] and [1].

The source code (Scala) is available at http://github.com/tjhunter/ Requires Spark 0.7, which will be released soon.

Understanding urban patterns

(Collaboration with Pu Wang and Marta González).

See [3].

Publications

Journals

Timothy Hunter, Tathagata Das, Matei Zaharia, Pieter Abbeel, Alexandre M. Bayen. Large Scale Estimation in Cyberphysical Systems using Streaming Data: a Case Study with Smartphone Traces. Under review for the IEEE Transactions on Automation Science and Engineering. Arxiv
Timothy Hunter, Pieter Abbeel, Alexandre M. Bayen. The Path Inference Filter: Model-Based Low-Latency Map Matching of Probe Vehicle Data. To appear in the IEEE Transactions on Intelligent Transportation Systems. Arxiv
Pu Wang, Timothy Hunter, Alexandre M. Bayen, Katja Schechtner, Marta C. González. Understanding Road Usage Patterns in Urban Areas. In Nature Scientific Reports. PDF DOI

Conferences

Timothy Hunter, Teodor Moldovan, Matei Zaharia, Samy Merzgui, Justin Ma, Michael J. Franklin, Pieter Abbeel, and Alexandre M. Bayen. Scaling the mobile millennium system in the cloud. In Proceedings of the 2nd ACM Symposium on Cloud Computing (SOCC), 2011. ACM, New York, NY, USA, , Article 28 , 8 pages. DOI PDF BIBTex Hide BIBTex

@inproceedings{Hunter:2011:SMM:2038916.2038944,
  author = {Hunter, Timothy and Moldovan, Teodor and Zaharia, Matei and Merzgui, Samy and Ma, Justin and Franklin, Michael J. and Abbeel, Pieter and Bayen, Alexandre M.},
  title = {Scaling the mobile millennium system in the cloud},
  booktitle = {Proceedings of the 2nd ACM Symposium on Cloud Computing},
  series = {SOCC '11},
  year = {2011},
  isbn = {978-1-4503-0976-9},
  location = {Cascais, Portugal},
  pages = {28:1--28:8},
  articleno = {28},
  numpages = {8},
  url = {http://doi.acm.org/10.1145/2038916.2038944},
  doi = {10.1145/2038916.2038944},
  acmid = {2038944},
  publisher = {ACM},
  address = {New York, NY, USA},
}

Timothy Hunter, Pieter Abbeel, Alexandre M. Bayen. The Path Inference Filter: Model-Based Low-Latency Map Matching of Probe Vehicle Data. In the 10th International Workshop on the Algorithmic Foundations of Robotics (WAFR), 2012. DOI PDF BIBTex Hide BIBTex

@inproceedings{hunter12wafr,
  author = {Hunter, Timothy and Abbeel, Pieter and Bayen, Alexandre M.},
  title = {The Path Inference Filter: Model-Based Low-Latency Map Matching of Probe Vehicle Data},
  booktitle = {Algorithmic Foundations of Robotics X},
  series = {Springer Tracts in Advanced Robotics},
  year = {2012},
  isbn = {978-3-642-36278-1},
  location = {Cambridge, MA, USA},
  pages = {591:1--607:17},
  articleno = {28},
  numpages = {17},
  url = {http://doi.acm.org/10.1145/2038916.2038944},
  doi = {10.1007/978-3-642-36279-8_36},
  publisher = {Springer-Verlag},
  address = {Heidelberg, Germany},
}

Workshops, technical reports

Timothy Hunter, Ryan Herring, Pieter Abbeel and Alex Bayen. Path and travel time inference from GPS probe vehicle data. At NIPS Analyzing Networks and Learning with Graphs, 2009. PDF
Timothy Hunter, Matei Zaharia, Tathagata Das, Pieter Abbeel and Alexandre Bayen. Large-Scale Online Expectation Maximization with Spark Streaming. At NIPS workshop on parallel and large-scale machine learning, 2012. PDF

Matei Zaharia, Tathagata Das, Haoyuan Li, Timothy Hunter, Scott Shenker, Ion Stoica. Discretized Streams: A Fault-Tolerant Model for Scalable Stream Processing. Technical Report No. UCB/EECS-2012-259. PDF BIBTex Hide BIBTex

@techreport{Zaharia:EECS-2012-259,
Author = {Zaharia, Matei and Das, Tathagata and Li, Haoyuan and Hunter, Timothy and Shenker, Scott and Stoica, Ion},
Title = {Discretized Streams: A Fault-Tolerant Model for Scalable Stream Processing},
Institution = {EECS Department, University of California, Berkeley},
Year = {2012},
Month = {Dec},
URL = {http://www.eecs.berkeley.edu/Pubs/TechRpts/2012/EECS-2012-259.html},
Number = {UCB/EECS-2012-259}
}

Talks

Large scale sensing and prediction, Alex Bayen and Timothy Hunter.
Keynote speech at the AMPLab retreat, October 2010.

Spark User Applications - Mobile Millennium.
Tutorial for the AMPLab Bootcamp.
Youtube

Older publications

Pieter Abbeel, Adam Coates, Timothy Hunter and Andrew Y. Ng 2009 Autonomous Autorotation of an RC Helicopter In Experimental Robotics DOI PDF BIBTex Hide BIBTex

@incollection{,
year={2009},
isbn={978-3-642-00195-6},
booktitle={Experimental Robotics},
volume={54},
series={Springer Tracts in Advanced Robotics},
editor={Khatib, Oussama and Kumar, Vijay and Pappas, GeorgeJ.},
doi={10.1007/978-3-642-00196-3_45},
title={Autonomous Autorotation of an RC Helicopter},
url={http://dx.doi.org/10.1007/978-3-642-00196-3_45},
publisher={Springer Berlin Heidelberg},
author={Abbeel, Pieter and Coates, Adam and Hunter, Timothy and Ng, AndrewY.},
pages={385-394}
}

Trivia

In the few spare times academia leaves me, I enjoy discovering and taking pictures of new places. You can see a few samples on my Picasa page.

Some say that I used to play magic tricks when I was in high school, according to this Wikipedia entry.

This web page was created using Pandoc and styled with Bootstrap, based on the excellent template from Jack Reilly. The CSS theme was autogenerated using Lavish. The source code for this page is available here.

Timothy J. Hunter

Ph. D. Student, Computer Science, UC Berkeley