AI4OPT Seminar Series

Date: Thursday, March 2, 2023

Time: Noon – 1:00 pm

Location: Instructional Center 115 (Scale Up Room) - (759 Ferst Dr, Atlanta, GA 30318)

Join Virtually: https://gatech.zoom.us/j/99381428980

Speaker: R. Srikant

An Algorithm for Crowdsourcing With Hard and Easy Tasks

Abstract: Crowdsourcing is a popular method used to estimate ground-truth labels by collecting noisy labels from workers. In this work, we are motivated by crowdsourcing applications where each worker can exhibit two levels of accuracy depending on a task’s type. Applying algorithms designed for the traditional Dawid-Skene model to such a scenario results in performance which is limited by the hard tasks. Therefore, we first extend the model to allow worker accuracy to vary depending on a task’s unknown type. Then we propose a spectral method to partition tasks by type. After separating tasks by type, any Dawid-Skene algorithm (i.e., any algorithm designed for the Dawid-Skene model) can be applied independently to each type to infer the truth values. We theoretically prove that when crowdsourced data contain tasks with varying levels of difficulty, our algorithm infers the true labels with higher accuracy than any Dawid-Skene algorithm. Experiments show that our method is effective in practical applications. Joint work with Seo-Taek Kong and Saptarshi Mandal.

Bio: R. Srikant is  a Grainger Chair in Engineering and Professor in the Department of Electrical and Computer Engineering and the Coordinated Science Lab, all at the University of Illinois at Urbana-Champaign. He is also the Co-Director of the C3.AI Digital Transformation Institute, jointly headquartered at Illinois and Berkeley. His research interests include applied probability, machine learning and communication networks. He is the recipient of the 2015 INFOCOM Achievement Award, the 2019 IEEE Koji Kobayashi Computers and  Communications Award and the 2021 ACM SIGMETRICS Achievement Award. He has also received several Best Paper awards including the 2015 INFOCOM Best Paper Award,  the 2017 Applied Probability Society Best Publication Award, and the 2017 WiOpt Best Paper award. He was the Editor-in-Chief of the IEEE/ACM Transactions on Networking from 2013-2017.

Lunch will be served at the seminar. So, please stop by 15 minutes before the seminar to pick up lunch.

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Past seminars can be found at https://www.ai4opt.org/seminars/past-seminars.