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Peter J. Ramadge

7 accepted papers

2022

Training Discrete Deep Generative Models via Gapped Straight-Through Estimator

ICML 2022spotlight

While deep generative models have succeeded in image processing, natural language processing, and reinforcement learning, training that involves discrete random variables remains challenging due to the high variance of its gradient estimation process. Monte Carlo is a common solution used in most va…

2021

Accelerating Safe Reinforcement Learning with Constraint-mismatched Baseline Policies

ICML 2021spotlight

We consider the problem of reinforcement learning when provided with (1) a baseline control policy and (2) a set of constraints that the learner must satisfy. The baseline policy can arise from demonstration data or a teacher agent and may provide useful cues for learning, but it might also be sub-o…

Cited by 26SourcePDFScholar
2020

Projection-Based Constrained Policy Optimization

ICLR 2020poster

We consider the problem of learning control policies that optimize a reward function while satisfying constraints due to considerations of safety, fairness, or other costs. We propose a new algorithm - Projection-Based Constrained Policy Optimization (PCPO), an iterative method for optimizing polici…

Cited by 307SourceScholar
2020

Task-Agnostic Amortized Inference of Gaussian Process Hyperparameters

NeurIPS 2020poster

Gaussian processes (GPs) are flexible priors for modeling functions. However, their success depends on the kernel accurately reflecting the properties of the data. One of the appeals of the GP framework is that the marginal likelihood of the kernel hyperparameters is often available in closed form,…

2017

A semi-supervised method for multi-subject FMRI functional alignment

ICASSP 2017accepted

Practical limitations on the duration of individual fMRI scans have led neuroscientist to consider the aggregation of data from multiple subjects. Differences in anatomical structures and functional topographies of brains require aligning data across subjects. Existing functional alignment methods s…

Cited by 0SourceScholar
2015

A Reduced-Dimension fMRI Shared Response Model

NeurIPS 2015oral

Multi-subject fMRI data is critical for evaluating the generality and validity of findings across subjects, and its effective utilization helps improve analysis sensitivity. We develop a shared response model for aggregating multi-subject fMRI data that accounts for different functional topographies…

Cited by 218SourcePDFScholar