Research
In recent years, AI has excelled in training extremely specialized agents to solve specific problems, from mastering games to achieving impressive classification accuracy on benchmark datasets. I view broadening the skills of these specialist agents as an exciting frontier. To achieve this, agents must be able to re-use knowledge gained in one setting and apply it in another. To this end, my PhD thesis research focused on representation learning and meta-learning for reinforcement learning problems. In the first few years of my PhD, I worked in computer vision on image segmentation. I got my start in machine learning in undergrad where I contributed to a project applying semi-supervised learning techniques to historical photographs to discover trends in fashion and hairstyle over the past century.
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Which Mutual-Information Representation Learning Objectives are Sufficient for Control?
Kate Rakelly, Abhishek Gupta, Carlos Florensa, Sergey Levine
Neurips, 2021
Unsupervised representation learning techniques can be used to extract compact state representations from observations, making the RL problem easier and more tractable. Recently, contrastive learning methods that learn lossy representations and can be interpreted as maximizing mutual information objectives have proven effective and popular. However, are the learned representations guaranteed to be capable of learning and representing the optimal policy? In other words, might they inadvertantly discard needed information for control? We present a framework for analysis and seek to answer this question for several popular and representative objectives.
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MELD: Meta-Reinforcement Learning from Images via Latent State Models
Tony Z. Zhao*, Anusha Nagabandi*, Kate Rakelly*, Chelsea Finn, Sergey Levine
CoRL, 2020
Code,
Website,
Video
We leverage the perspective of meta-learning as task inference to show that latent state models can also perform meta-learning given an appropriately defined observation space. Building on this insight, we develop meta-RL with latent dynamics (MELD), an algorithm for meta-RL from images that performs inference in a latent state model to quickly acquire new skills given observations and rewards. We demonstrate that MELD enables the WidowX robotic arm to quickly insert an Ethernet cable into the correct port at a novel location and orientation given only a task completion reward.
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Efficient Off-Policy Meta-Reinforcement Learning via Probabilistic Context Variables
Kate Rakelly*, Aurick Zhou*, Deirdre Quillen, Chelsea Finn, Sergey Levine
ICML, 2019
Code,
Blog,
Slides
Leverage off-policy learning and a probabilistic belief over the task to make meta-RL 20-100X more sample efficient. PEARL performs online probabilistic filtering of latent task variables to infer how to solve a new task from small amounts of experience. This probabilistic interpretation enables posterior sampling for structured and efficient exploration during adaptation. Unlike prior approaches, our method integrates easily with existing off-policy RL algorithms, greatly improving meta-training sample efficiency.
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Few-Shot Segmentation Propagation with Guided Networks
Kate Rakelly*, Evan Shelhamer*, Trevor Darrell, Alyosha Efros, Sergey Levine
Preprint, 2018
Code
Few-shot learning meets segmentation: given a few labeled pixels from few images, segment new images accordingly. Our guided network extracts a latent task representation from any amount of supervision and is optimized end-to-end for fast, accurate segmentation of new inputs. We show state-of-the-art results for speed and amount of supervision on three segmentation problems that are usually treated separately: interactive, semantic, and video object segmentation. Our method is fast enough to perform real-time interactive video object segmentation.
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Clockwork Convnets for Video Semantic Segmentation
Evan Shelhamer*, Kate Rakelly*, Judy Hoffman*, Trevor Darrell
Video Semantic Segmentation Workshop at European Conference in Computer Vision (ECCV), 2016
Code
A fast video recognition framework that relies on
two key observations: 1) while pixels may change rapidly from frame to frame,
the semantic content of a scene evolves more slowly, and 2) execution can be
viewed as an aspect of architecture, yielding purpose-fit computation schedules
for networks. We define a novel family of "clockwork" convnets driven by fixed
or adaptive clock signals that schedule the processing of different layers at different
update rates according to their semantic stability.
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CS294-112 - Fall 2018 (Head Teaching Assistant)
Deep Reinforcement Learning is a special topics course covering modern deep reinforcement learning techniques.
CS70 - Summer 2014 (Teaching Assistant)
Discrete Mathematics for Computer Science covers proof techniques, modular arithmetic, polynomials, and probability.
EE40 - Summer 2013 (Teaching Assistant)
Introduction to Circuits covers analyzing, designing, and building electronic circuits using op amps and passive components. (Note this class along with EE20 have been replaced by the EE16A/B series as of Fall 2015.)
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English (fluent), Spanish (proficient)
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Other skills and interests
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I am an amateur vocalist and guitar player, and have recently dabbled in writing songs! I'm particularly interested in folk, soft rock, and Latin pop. I love listening to all kinds of live music, from symphony orchestra to singer-songwriters to dance bands.
I love to be oustide, near the ocean or in the mountains. Rock climbing and hiking are some of my favorite ways to enjoy the outdoors.
I love good food, wine, coffee, and tea!
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