Publications

2019-09-30

Neural Networks (published)

Evaluation of a web-based tool for labelling potential hospital outbreaks: a mixed methods study

B. Leclère

David L Buckeridge

D. Lepelletier

2019-09-30

Journal of Hospital Infection (published)

Learning Fixed Points in Generative Adversarial Networks: From Image-to-Image Translation to Disease Detection and Localization

Md Mahfuzur Rahman Siddiquee

Zongwei Zhou

Nima Tajbakhsh

Ruibin Feng

Michael B. Gotway

Jianming Liang

Generative adversarial networks (GANs) have ushered in a revolution in image-to-image translation. The development and proliferation of GANs… (see more) raises an interesting question: can we train a GAN to remove an object, if present, from an image while otherwise preserving the image? Specifically, can a GAN "virtually heal" anyone by turning his medical image, with an unknown health status (diseased or healthy), into a healthy one, so that diseased regions could be revealed by subtracting those two images? Such a task requires a GAN to identify a minimal subset of target pixels for domain translation, an ability that we call fixed-point translation, which no GAN is equipped with yet. Therefore, we propose a new GAN, called Fixed-Point GAN, trained by (1) supervising same-domain translation through a conditional identity loss, and (2) regularizing cross-domain translation through revised adversarial, domain classification, and cycle consistency loss. Based on fixed-point translation, we further derive a novel framework for disease detection and localization using only image-level annotation. Qualitative and quantitative evaluations demonstrate that the proposed method outperforms the state of the art in multi-domain image-to-image translation and that it surpasses predominant weakly-supervised localization methods in both disease detection and localization. Implementation is available at https://github.com/jlianglab/Fixed-Point-GAN.

2019-09-30

2019 IEEE/CVF International Conference on Computer Vision (ICCV) (published)

{COMPANYNAME}11K: An Unsupervised Representation Learning Dataset for Arrhythmia Subtype Discovery

Guillaume Androz

Pierre Fecteau

2019-09-24

(published)

Equivariant Entity-Relationship Networks

Devon Graham

Siamak Ravanbakhsh

The relational model is a ubiquitous representation of big-data, in part due to its extensive use in databases. In this paper, we propose th… (see more)e Equivariant Entity-Relationship Network (EERN), which is a Multilayer Perceptron equivariant to the symmetry transformations of the Entity-Relationship model. To this end, we identify the most expressive family of linear maps that are exactly equivariant to entity relationship symmetries, and further show that they subsume recently introduced equivariant maps for sets, exchangeable tensors, and graphs. The proposed feed-forward layer has linear complexity in the data and can be used for both inductive and transductive reasoning about relational databases, including database embedding, and the prediction of missing records. This provides a principled theoretical foundation for the application of deep learning to one of the most abundant forms of data. Empirically, EERN outperforms different variants of coupled matrix tensor factorization in both synthetic and real-data experiments.

2019-09-24

(published)

HighRes-net: Multi-Frame Super-Resolution by Recursive Fusion

Michel Deudon

Alfredo Kalaitzis

Md Rifat Arefin

Israel Goytom

Zhichao Lin

Kris Sankaran

Vincent Michalski

S Ebrahimi Kahou

Julien Cornebise

2019-09-24

(published)

Learning Neural Causal Models from Unknown Interventions

Nan Rosemary Ke

Christopher Pal

Promising results have driven a recent surge of interest in continuous optimization methods for Bayesian network structure learning from obs… (see more)ervational data. However, there are theoretical limitations on the identifiability of underlying structures obtained from observational data alone. Interventional data provides much richer information about the underlying data-generating process. However, the extension and application of methods designed for observational data to include interventions is not straightforward and remains an open problem. In this paper we provide a general framework based on continuous optimization and neural networks to create models for the combination of observational and interventional data. The proposed method is even applicable in the challenging and realistic case that the identity of the intervened upon variable is unknown. We examine the proposed method in the setting of graph recovery both de novo and from a partially-known edge set. We establish strong benchmark results on several structure learning tasks, including structure recovery of both synthetic graphs as well as standard graphs from the Bayesian Network Repository.

2019-09-24

arXiv (preprint)

Selfish Emergent Communication

Michael Noukhovitch

Travis LaCroix

Aaron Courville

2019-09-24

(published)

SPECTRA: Sparse Entity-centric Transitions

Rim Assouel

Learning an agent that interacts with objects is ubiquituous in many RL tasks. In most of them the agent’s actions have sparse effects : o… (see more)nly a small subset of objects in the visual scene will be affected by the action taken. We introduce SPECTRA, a model for learning slot-structured transitions from raw visual observations that embodies this sparsity assumption. Our model is composed of a perception module that decomposes the visual scene into a set of latent objects representations (i.e. slot-structured) and a transition module that predicts the next latent set slot-wise and in a sparse way. We show that learning a perception module jointly with a sparse slot-structured transition model not only biases the model towards more entity-centric perceptual groupings but also enables intrinsic exploration strategy that aims at maximizing the number of objects changed in the agents trajectory.

2019-09-24

(published)

On summarized validation curves and generalization

Mohammad Hashir

Joseph Paul Cohen

2019-09-24

(published)

Avoidance Learning Using Observational Reinforcement Learning

David Venuto

Léonard Boussioux

Junhao Wang

Rola Dali

Jhelum Chakravorty

Doina Precup

Imitation learning seeks to learn an expert policy from sampled demonstrations. However, in the real world, it is often difficult to find a … (see more)perfect expert and avoiding dangerous behaviors becomes relevant for safety reasons. We present the idea of \textit{learning to avoid}, an objective opposite to imitation learning in some sense, where an agent learns to avoid a demonstrator policy given an environment. We define avoidance learning as the process of optimizing the agent's reward while avoiding dangerous behaviors given by a demonstrator. In this work we develop a framework of avoidance learning by defining a suitable objective function for these problems which involves the \emph{distance} of state occupancy distributions of the expert and demonstrator policies. We use density estimates for state occupancy measures and use the aforementioned distance as the reward bonus for avoiding the demonstrator. We validate our theory with experiments using a wide range of partially observable environments. Experimental results show that we are able to improve sample efficiency during training compared to state of the art policy optimization and safety methods.

2019-09-23

arXiv (Cornell University) (preprint)

Learning Sparse Mixture of Experts for Visual Question Answering

Vardaan Pahuja

Jie Fu

Christopher Pal

2019-09-18

ArXiv (preprint)