Search Results for author: Ehsan Hajiramezanali

Found 19 papers, 8 papers with code

Feedback Efficient Online Fine-Tuning of Diffusion Models

no code implementations26 Feb 2024 Masatoshi Uehara, Yulai Zhao, Kevin Black, Ehsan Hajiramezanali, Gabriele Scalia, Nathaniel Lee Diamant, Alex M Tseng, Sergey Levine, Tommaso Biancalani

It is natural to frame this as a reinforcement learning (RL) problem, in which the objective is to fine-tune a diffusion model to maximize a reward function that corresponds to some property.

reinforcement-learning Reinforcement Learning (RL)

Toward the Identifiability of Comparative Deep Generative Models

no code implementations29 Jan 2024 Romain Lopez, Jan-Christian Huetter, Ehsan Hajiramezanali, Jonathan Pritchard, Aviv Regev

Finally, we introduce a novel methodology for fitting comparative DGMs that improves the treatment of multiple data sources via multi-objective optimization and that helps adjust the hyperparameter for the regularization in an interpretable manner, using constrained optimization.

Conformalized Deep Splines for Optimal and Efficient Prediction Sets

1 code implementation1 Nov 2023 Nathaniel Diamant, Ehsan Hajiramezanali, Tommaso Biancalani, Gabriele Scalia

SPICE is compatible with two different efficient-to-compute conformal scores, one oracle-optimal for marginal coverage (SPICE-ND) and the other asymptotically optimal for conditional coverage (SPICE-HPD).

Conformal Prediction Prediction Intervals

Towards Understanding and Improving GFlowNet Training

1 code implementation11 May 2023 Max W. Shen, Emmanuel Bengio, Ehsan Hajiramezanali, Andreas Loukas, Kyunghyun Cho, Tommaso Biancalani

We investigate how to learn better flows, and propose (i) prioritized replay training of high-reward $x$, (ii) relative edge flow policy parametrization, and (iii) a novel guided trajectory balance objective, and show how it can solve a substructure credit assignment problem.

Parameter Averaging for Feature Ranking

no code implementations5 Aug 2022 Talip Ucar, Ehsan Hajiramezanali

We conduct extensive experiments on a variety of synthetic and real-world data, demonstrating that the XTab can be used to obtain the global feature importance that is not sensitive to sub-optimal model initialisation.

Decision Making Feature Importance +1

MoReL: Multi-omics Relational Learning

no code implementations ICLR 2022 Arman Hasanzadeh, Ehsan Hajiramezanali, Nick Duffield, Xiaoning Qian

Multi-omics data analysis has the potential to discover hidden molecular interactions, revealing potential regulatory and/or signal transduction pathways for cellular processes of interest when studying life and disease systems.

Graph Embedding Relational Reasoning

Bayesian Graph Contrastive Learning

no code implementations15 Dec 2021 Arman Hasanzadeh, Mohammadreza Armandpour, Ehsan Hajiramezanali, Mingyuan Zhou, Nick Duffield, Krishna Narayanan

By learning distributional representations, we provide uncertainty estimates in downstream graph analytics tasks and increase the expressive power of the predictive model.

Contrastive Learning Self-Supervised Learning +1

SubTab: Subsetting Features of Tabular Data for Self-Supervised Representation Learning

2 code implementations NeurIPS 2021 Talip Ucar, Ehsan Hajiramezanali, Lindsay Edwards

Self-supervised learning has been shown to be very effective in learning useful representations, and yet much of the success is achieved in data types such as images, audio, and text.

Collaborative Inference Contrastive Learning +2

Bayesian Relational Generative Model for Scalable Multi-modal Learning

no code implementations29 Sep 2021 Ehsan Hajiramezanali, Talip Ucar, Lindsay Edwards

First, they are not stochastic processes, leading to poor uncertainty estimations over their predictions.

Gaussian Processes

SimCD: Simultaneous Clustering and Differential expression analysis for single-cell transcriptomic data

1 code implementation4 Apr 2021 Seyednami Niyakan, Ehsan Hajiramezanali, Shahin Boluki, Siamak Zamani Dadaneh, Xiaoning Qian

We develop a new method -- SimCD -- that explicitly models cell heterogeneity and dynamic differential changes in one unified hierarchical gamma-negative binomial (hGNB) model, allowing simultaneous cell clustering and differential expression analysis for scRNA-seq data.

Clustering

BayReL: Bayesian Relational Learning for Multi-omics Data Integration

1 code implementation NeurIPS 2020 Ehsan Hajiramezanali, Arman Hasanzadeh, Nick Duffield, Krishna R Narayanan, Xiaoning Qian

High-throughput molecular profiling technologies have produced high-dimensional multi-omics data, enabling systematic understanding of living systems at the genome scale.

Data Integration Relational Reasoning +1

Bayesian Graph Neural Networks with Adaptive Connection Sampling

1 code implementation ICML 2020 Arman Hasanzadeh, Ehsan Hajiramezanali, Shahin Boluki, Mingyuan Zhou, Nick Duffield, Krishna Narayanan, Xiaoning Qian

We propose a unified framework for adaptive connection sampling in graph neural networks (GNNs) that generalizes existing stochastic regularization methods for training GNNs.

Node Classification

Semi-Implicit Stochastic Recurrent Neural Networks

no code implementations28 Oct 2019 Ehsan Hajiramezanali, Arman Hasanzadeh, Nick Duffield, Krishna Narayanan, Mingyuan Zhou, Xiaoning Qian

Stochastic recurrent neural networks with latent random variables of complex dependency structures have shown to be more successful in modeling sequential data than deterministic deep models.

Variational Inference

Variational Graph Recurrent Neural Networks

2 code implementations NeurIPS 2019 Ehsan Hajiramezanali, Arman Hasanzadeh, Nick Duffield, Krishna R. Narayanan, Mingyuan Zhou, Xiaoning Qian

Representation learning over graph structured data has been mostly studied in static graph settings while efforts for modeling dynamic graphs are still scant.

Attribute Dynamic Link Prediction +2

Semi-Implicit Graph Variational Auto-Encoders

1 code implementation NeurIPS 2019 Arman Hasanzadeh, Ehsan Hajiramezanali, Nick Duffield, Krishna R. Narayanan, Mingyuan Zhou, Xiaoning Qian

Compared to VGAE, the derived graph latent representations by SIG-VAE are more interpretable, due to more expressive generative model and more faithful inference enabled by the flexible semi-implicit construction.

Variational Inference

Bayesian multi-domain learning for cancer subtype discovery from next-generation sequencing count data

no code implementations NeurIPS 2018 Ehsan Hajiramezanali, Siamak Zamani Dadaneh, Alireza Karbalayghareh, Mingyuan Zhou, Xiaoning Qian

Second, compared to the number of involved molecules and system complexity, the number of available samples for studying complex disease, such as cancer, is often limited, especially considering disease heterogeneity.

Multi-Task Learning

Differential Expression Analysis of Dynamical Sequencing Count Data with a Gamma Markov Chain

no code implementations7 Mar 2018 Ehsan Hajiramezanali, Siamak Zamani Dadaneh, Paul de Figueiredo, Sing-Hoi Sze, Mingyuan Zhou, Xiaoning Qian

Next-generation sequencing (NGS) to profile temporal changes in living systems is gaining more attention for deriving better insights into the underlying biological mechanisms compared to traditional static sequencing experiments.

Data Augmentation

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