Graduate Student Researcher
330 Sutardja Dai Hall, 652B
Berkeley, CA 94720United States
DATA-DRIVEN ROUTE FLOW ESTIMATION
Given data from the cellular network, loop counts, license plate readers, and similar types of sensors on road networks, we estimate the link flow, OD flow, and route flow of a road network. First, the origin-destination (OD) demands are estimated by aggregating phone records by area and timestamp. Then, the problem of estimating route flows given the estimated OD demands and the sensor measurements is formulated as a quadratic program with block-simplex constraints. A change of variable reduces the dimensionality of the problem in which the simplex constraints become order constraints. We apply first and second order projected descent methods in which the projection is the solution of an isotonic regression problem with box constraints. Finally, we show that our method can be used to reconstruct link flows. We show that our algorithm scales well to the full-scale network of the greater Los Angeles area. We additionally benchmark our method against several other natural approaches for the block-simplex signal recovery problem, including compressed sensing and Bayesian inference. This project is joint work with Jérôme Thai, Steve Yadlowsky, Sara-Fleur Sultan, Prof. Alexei Pozdnoukhov, and Prof. Alex Bayen.
Cathy Wu received a Master of Engineering degree in Electrical Engineering and Computer Science (EECS) (2013) and a Bachelor of Science degree in EECS (2012) from the Massachusetts Institute of Technology (MIT). She is currently pursuing her Ph.D in the Department of EECS at the University of California, Berkeley. Cathy's research interests are at the intersection of control theory, optimization, statistics, and cyber-physical systems - with problems motivated by transportation systems.
RECENT JOURNAL PAPERS
Cathy Wu, Jerome Thai, Steve Yadlowsky, Alexei Pozdnoukhov, Alexandre Bayen. Cellpath: fusion of cellular and traffic sensor data for route flow estimation via convex optimization. International Symposium on Transportation and Traffic Theory (ISTTT) and Transportation Research: Part B, 2015. To appear.
RECENT CONFERENCE PAPERS
Steve Yadlowsky, Jerome Thai, Cathy Wu, Alexei Pozdnoukhov, Alexandre Bayen. Link Density Inference from Cellular Infrastructure. Transportation Research Board (TRB) Annual Meeting and Transportation Research Record (TRR), 2015. To appear.