1 code implementation • 19 Oct 2023 • Sulin Liu, Peter J. Ramadge, Ryan P. Adams
We introduce marginalization models (MAMs), a new family of generative models for high-dimensional discrete data.
no code implementations • 23 May 2023 • Ta-Chung Chi, Ting-Han Fan, Li-Wei Chen, Alexander I. Rudnicky, Peter J. Ramadge
The use of positional embeddings in transformer language models is widely accepted.
no code implementations • 5 May 2023 • Ta-Chung Chi, Ting-Han Fan, Alexander I. Rudnicky, Peter J. Ramadge
Unlike recurrent models, conventional wisdom has it that Transformers cannot perfectly model regular languages.
no code implementations • 20 Dec 2022 • Ta-Chung Chi, Ting-Han Fan, Alexander I. Rudnicky, Peter J. Ramadge
Length extrapolation permits training a transformer language model on short sequences that preserves perplexities when tested on substantially longer sequences.
1 code implementation • 15 Jun 2022 • Ting-Han Fan, Ta-Chung Chi, Alexander I. Rudnicky, Peter J. Ramadge
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.
2 code implementations • 20 May 2022 • Ta-Chung Chi, Ting-Han Fan, Peter J. Ramadge, Alexander I. Rudnicky
Relative positional embeddings (RPE) have received considerable attention since RPEs effectively model the relative distance among tokens and enable length extrapolation.
1 code implementation • 22 Dec 2021 • Athindran Ramesh Kumar, Sulin Liu, Jaime F. Fisac, Ryan P. Adams, Peter J. Ramadge
In practice, we have inaccurate knowledge of the system dynamics, which can lead to unsafe behaviors due to unmodeled residual dynamics.
1 code implementation • 6 Oct 2021 • Ting-Han Fan, Peter J. Ramadge
Off-policy Actor-Critic algorithms have demonstrated phenomenal experimental performance but still require better explanations.
no code implementations • 19 Jun 2021 • Athindran Ramesh Kumar, Peter J. Ramadge
Since most industrial control applications use PID controllers, PID tuning and anti-windup measures are significant problems.
1 code implementation • NeurIPS 2020 • Sulin Liu, Xingyuan Sun, Peter J. Ramadge, Ryan P. Adams
One of the appeals of the GP framework is that the marginal likelihood of the kernel hyperparameters is often available in closed form, enabling optimization and sampling procedures to fit these hyperparameters to data.
no code implementations • NeurIPS 2021 • Tsung-Yen Yang, Michael Hu, Yinlam Chow, Peter J. Ramadge, Karthik Narasimhan
We then develop an agent with a modular architecture that can interpret and adhere to such textual constraints while learning new tasks.
no code implementations • ICLR 2020 • Tsung-Yen Yang, Justinian Rosca, Karthik Narasimhan, Peter J. Ramadge
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.
no code implementations • 18 Sep 2020 • Ting-Han Fan, Peter J. Ramadge
Despite its experimental success, Model-based Reinforcement Learning still lacks a complete theoretical understanding.
no code implementations • 20 Jun 2020 • Tsung-Yen Yang, Justinian Rosca, Karthik Narasimhan, Peter J. Ramadge
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.
no code implementations • 27 Feb 2020 • Hossein Valavi, Sulin Liu, Peter J. Ramadge
We show that, in contrast to the general situation, the minimum eigenvalue of strict saddles in $\mathcal{M}_{0}$ is uniformly bounded below zero.
no code implementations • 25 Sep 2019 • Yueh-Hua Wu, Ting-Han Fan, Peter J. Ramadge, Hao Su
Based on the claim, we propose to learn the transition model by matching the distributions of multi-step rollouts sampled from the transition model and the real ones via WGAN.
no code implementations • 25 Feb 2019 • Sara Fridovich-Keil, Peter J. Ramadge
We consider the problem of smartphone video-based heart rate estimation, which typically relies on measuring the green color intensity of the user's skin.
Medical Physics Image and Video Processing
2 code implementations • 28 Nov 2018 • Qihong Lu, Po-Hsuan Chen, Jonathan W. Pillow, Peter J. Ramadge, Kenneth A. Norman, Uri Hasson
Different neural networks trained on the same dataset often learn similar input-output mappings with very different weights.
no code implementations • 29 Sep 2016 • Hejia Zhang, Po-Hsuan Chen, Janice Chen, Xia Zhu, Javier S. Turek, Theodore L. Willke, Uri Hasson, Peter J. Ramadge
In this work, we examine a searchlight based shared response model to identify shared information in small contiguous regions (searchlights) across the whole brain.
no code implementations • 21 Aug 2016 • Yun Wang, Xu Chen, Peter J. Ramadge
In this context, we propose and explore a feedback controlled sequential screening scheme.
no code implementations • 21 Aug 2016 • Yun Wang, Peter J. Ramadge
Recently dictionary screening has been proposed as an effective way to improve the computational efficiency of solving the lasso problem, which is one of the most commonly used method for learning sparse representations.
no code implementations • 17 Aug 2016 • Po-Hsuan Chen, Xia Zhu, Hejia Zhang, Javier S. Turek, Janice Chen, Theodore L. Willke, Uri Hasson, Peter J. Ramadge
We examine two ways to combine the ideas of a factor model and a searchlight based analysis to aggregate multi-subject fMRI data while preserving spatial locality.
no code implementations • 16 Aug 2016 • Michael J. Anderson, Mihai Capotă, Javier S. Turek, Xia Zhu, Theodore L. Willke, Yida Wang, Po-Hsuan Chen, Jeremy R. Manning, Peter J. Ramadge, Kenneth A. Norman
The scale of functional magnetic resonance image data is rapidly increasing as large multi-subject datasets are becoming widely available and high-resolution scanners are adopted.
no code implementations • NeurIPS 2015 • Po-Hsuan (Cameron) Chen, Janice Chen, Yaara Yeshurun, Uri Hasson, James Haxby, Peter J. Ramadge
Multi-subject fMRI data is critical for evaluating the generality and validity of findings across subjects, and its effective utilization helps improve analysis sensitivity.
no code implementations • 19 May 2014 • Zhen James Xiang, Yun Wang, Peter J. Ramadge
For a given target vector, dictionary screening quickly identifies a subset of dictionary columns that will receive zero weight in a solution of the corresponding lasso problem.
no code implementations • NeurIPS 2012 • Alexander Lorbert, Peter J. Ramadge
We offer a regularized, kernel extension of the multi-set, orthogonal Procrustes problem, or hyperalignment.
no code implementations • NeurIPS 2009 • Bryan Conroy, Ben Singer, James Haxby, Peter J. Ramadge
The inter-subject alignment of functional MRI (fMRI) data is important for improving the statistical power of fMRI group analyses.
no code implementations • NeurIPS 2009 • Yongxin Xi, Uri Hasson, Peter J. Ramadge, Zhen J. Xiang
We prove that the proposed algorithm exhibits a ``grouping effect, which encourages the selection of all spatially local, discriminative base classifiers.