Publications

This document contains the description of dataset collected during the first round of Conversational Intelligence Challenge (ConvAI) which t… (see more)ook place in July 2017. During this evaluation round we collected over 2,500 dialogues from 10 chatbots and 500 volunteers. Here we provide the analysis of dataset statistics and outline some possible improvements for future data collection experiments.

Deep Complex Networks

Chiheb Trabelsi

Olexa Bilaniuk

Ying Zhang

Dmitriy Serdyuk

Sandeep Subramanian

Joao Felipe Santos

Soroush Mehri

Negar Rostamzadeh

Chris Pal

At present, the vast majority of building blocks, techniques, and architectures for deep learning are based on real-valued operations and re… (see more)presentations. However, recent work on recurrent neural networks and older fundamental theoretical analysis suggests that complex numbers could have a richer representational capacity and could also facilitate noise-robust memory retrieval mechanisms. Despite their attractive properties and potential for opening up entirely new neural architectures, complex-valued deep neural networks have been marginalized due to the absence of the building blocks required to design such models. In this work, we provide the key atomic components for complex-valued deep neural networks and apply them to convolutional feed-forward networks. More precisely, we rely on complex convolutions and present algorithms for complex batch-normalization, complex weight initialization strategies for complex-valued neural nets and we use them in experiments with end-to-end training schemes. We demonstrate that such complex-valued models are competitive with their real-valued counterparts. We test deep complex models on several computer vision tasks, on music transcription using the MusicNet dataset and on Speech spectrum prediction using TIMIT. We achieve state-of-the-art performance on these audio-related tasks.

2018-01-01

ICLR.cc/2018/Conference (poster)

Dendritic cortical microcircuits approximate the backpropagation algorithm

João Sacramento

Rui Ponte Costa

Walter Senn

Deep learning has seen remarkable developments over the last years, many of them inspired by neuroscience. However, the main learning mechan… (see more)ism behind these advances - error backpropagation - appears to be at odds with neurobiology. Here, we introduce a multilayer neuronal network model with simplified dendritic compartments in which error-driven synaptic plasticity adapts the network towards a global desired output. In contrast to previous work our model does not require separate phases and synaptic learning is driven by local dendritic prediction errors continuously in time. Such errors originate at apical dendrites and occur due to a mismatch between predictive input from lateral interneurons and activity from actual top-down feedback. Through the use of simple dendritic compartments and different cell-types our model can represent both error and normal activity within a pyramidal neuron. We demonstrate the learning capabilities of the model in regression and classification tasks, and show analytically that it approximates the error backpropagation algorithm. Moreover, our framework is consistent with recent observations of learning between brain areas and the architecture of cortical microcircuits. Overall, we introduce a novel view of learning on dendritic cortical circuits and on how the brain may solve the long-standing synaptic credit assignment problem.

FigureQA: An Annotated Figure Dataset for Visual Reasoning

Samira Ebrahimi Kahou

Adam Atkinson

Vincent Michalski

Ákos Kádár

Adam Trischler

We introduce FigureQA, a visual reasoning corpus of over one million question-answer pairs grounded in over 100,000 images. The images are s… (see more)ynthetic, scientific-style figures from five classes: line plots, dot-line plots, vertical and horizontal bar graphs, and pie charts. We formulate our reasoning task by generating questions from 15 templates; questions concern various relationships between plot elements and examine characteristics like the maximum, the minimum, area-under-the-curve, smoothness, and intersection. To resolve, such questions often require reference to multiple plot elements and synthesis of information distributed spatially throughout a figure. To facilitate the training of machine learning systems, the corpus also includes side data that can be used to formulate auxiliary objectives. In particular, we provide the numerical data used to generate each figure as well as bounding-box annotations for all plot elements. We study the proposed visual reasoning task by training several models, including the recently proposed Relation Network as a strong baseline. Preliminary results indicate that the task poses a significant machine learning challenge. We envision FigureQA as a first step towards developing models that can intuitively recognize patterns from visual representations of data.

2018-01-01

ICLR.cc/2018/Conference (Invite to Workshop Track)

Frank-Wolfe Splitting via Augmented Lagrangian Method

Gauthier Gidel

Fabian Pedregosa

Simon Lacoste-Julien

Minimizing a function over an intersection of convex sets is an important task in optimization that is often much more challenging than mini… (see more)mizing it over each individual constraint set. While traditional methods such as Frank-Wolfe (FW) or proximal gradient descent assume access to a linear or quadratic oracle on the intersection, splitting techniques take advantage of the structure of each sets, and only require access to the oracle on the individual constraints. In this work, we develop and analyze the Frank-Wolfe Augmented Lagrangian (FW-AL) algorithm, a method for minimizing a smooth function over convex compact sets related by a "linear consistency" constraint that only requires access to a linear minimization oracle over the individual constraints. It is based on the Augmented Lagrangian Method (ALM), also known as Method of Multipliers, but unlike most existing splitting methods, it only requires access to linear (instead of quadratic) minimization oracles. We use recent advances in the analysis of Frank-Wolfe and the alternating direction method of multipliers algorithms to prove a sublinear convergence rate for FW-AL over general convex compact sets and a linear convergence rate for polytopes.

2018-01-01

AISTATS (published)

proceedings.mlr.press

Fraternal Dropout

Konrad Żołna

Devansh Arpit

Dendi Suhubdy

2018-01-01

ICLR.cc/2018/Conference (poster)

Fraternal Dropout

Konrad Żołna

Devansh Arpit

Dendi Suhubdy

Recurrent neural networks (RNNs) are important class of architectures among neural networks useful for language modeling and sequential pred… (see more)iction. However, optimizing RNNs is known to be harder compared to feed-forward neural networks. A number of techniques have been proposed in literature to address this problem. In this paper we propose a simple technique called fraternal dropout that takes advantage of dropout to achieve this goal. Specifically, we propose to train two identical copies of an RNN (that share parameters) with different dropout masks while minimizing the difference between their (pre-softmax) predictions. In this way our regularization encourages the representations of RNNs to be invariant to dropout mask, thus being robust. We show that our regularization term is upper bounded by the expectation-linear dropout objective which has been shown to address the gap due to the difference between the train and inference phases of dropout. We evaluate our model and achieve state-of-the-art results in sequence modeling tasks on two benchmark datasets - Penn Treebank and Wikitext-2. We also show that our approach leads to performance improvement by a significant margin in image captioning (Microsoft COCO) and semi-supervised (CIFAR-10) tasks.

2018-01-01

ICLR (Poster) (published)

Graph Attention Networks

Petar Veličković

Guillem Cucurull

Arantxa Casanova

Adriana Romero Soriano

Pietro Lio

2018-01-01

ICLR.cc/2018/Conference (poster)

A Hierarchical Neural Attention-based Text Classifier

Koustuv Sinha

Yue Dong

Jackie Cheung

Derek Ruths

Deep neural networks have been displaying superior performance over traditional supervised classifiers in text classification. They learn to… (see more) extract useful features automatically when sufficient amount of data is presented. However, along with the growth in the number of documents comes the increase in the number of categories, which often results in poor performance of the multiclass classifiers. In this work, we use external knowledge in the form of topic category taxonomies to aide the classification by introducing a deep hierarchical neural attention-based classifier. Our model performs better than or comparable to state-of-the-art hierarchical models at significantly lower computational cost while maintaining high interpretability.

2018-01-01

Conference on Empirical Methods in Natural Language Processing (published)

doi.org

HoME: a Household Multimodal Environment

Simon Brodeur

Ethan Perez

Ankesh Anand

Florian Golemo

Luca Celotti

Florian Strub

Jean Rouat

Hugo Larochelle

Aaron Courville

We introduce HoME: a Household Multimodal Environment for artificial agents to learn from vision, audio, semantics, physics, and interaction… (see more) with objects and other agents, all within a realistic context. HoME integrates over 45,000 diverse 3D house layouts based on the SUNCG dataset, a scale which may facilitate learning, generalization, and transfer. HoME is an open-source, OpenAI Gym-compatible platform extensible to tasks in reinforcement learning, language grounding, sound-based navigation, robotics, multi-agent learning, and more. We hope HoME better enables artificial agents to learn as humans do: in an interactive, multimodal, and richly contextualized setting.

2018-01-01

ICLR (Workshop) (published)

How can we do better ? Pitfalls in biomedical challenge design and how to address them

Annika Reinke

Matthias Eisenmann

Sinan Onogur

Marko Stankovic

Patrick Scholz

Tal Arbel

Hrvoje Bogunovic

Andrew P. Bradley

Aaron

Carass

Carolin Feldmann

Alejandro F. Frangi

Peter M. Full

Bram Ginneken Van

Ginneken

Allan Hanbury

Katrin Honauer

Michal Kozubek

Adam Bennett

Landman … (see 22 more)

Keno März

Oskar Maier

Klaus Maier-Hein

Bjoern Menze

Henning Müller

Peter F. Neher

Wiro Niessen

NASIR RAJPOOT

Catherine Gregory

Sharp

Korsuk Sirinukunwattana

Stefanie Speidel

Christian Stock

Danail

Stoyanov

Abdel Aziz Taha

F. V. D. Sommen

Ching-Wei Wang

Marc-André Weber

Guoyan Zheng

Pierre Jannin

Lena Maier-Hein

Since the first MICCAI grand challenge was organized in 2007 [1], the impact of biomedical image analysis challenges on both the research fi… (see more)eld as well as on individual careers has been steadily growing. For example, the acceptance of a journal article today often depends on the performance of a new algorithm being assessed against the state-ofthe-art work on publicly available challenge datasets. Furthermore, the results are also important for the individuals scientific careers as well as the potential that algorithms can be translated into clinical practice. Yet, while the publication of papers in scientific journals and prestigious conferences, such as MICCAI, undergoes strict quality control, the design and organization of challenges do not. To investigate the effect of common practice, we have formed an international initiative dedicated to analyzing and improving a variety of aspects related to biomedical challenge design, execution and reporting [2]. In the first part of our abstract presentation at LABELS workshop, we are going to present some of the major pitfalls related to biomedical image analysis challenges today. Specifically, we will look at the following research questions: RQ1: How robust are challenge rankings? What is the effect of – the specific test cases used? – the specific metric variant(s) applied? – the rank aggregation method chosen (e.g. aggregation of metric values with the mean vs median)? ? Shared first/senior authors.

Image-to-image translation for cross-domain disentanglement

Abel Gonzalez-Garcia

Joost van de Weijer

Deep image translation methods have recently shown excellent results, outputting high-quality images covering multiple modes of the data dis… (see more)tribution. There has also been increased interest in disentangling the internal representations learned by deep methods to further improve their performance and achieve a finer control. In this paper, we bridge these two objectives and introduce the concept of cross-domain disentanglement. We aim to separate the internal representation into three parts. The shared part contains information for both domains. The exclusive parts, on the other hand, contain only factors of variation that are particular to each domain. We achieve this through bidirectional image translation based on Generative Adversarial Networks and cross-domain autoencoders, a novel network component. Our model offers multiple advantages. We can output diverse samples covering multiple modes of the distributions of both domains, perform domain-specific image transfer and interpolation, and cross-domain retrieval without the need of labeled data, only paired images. We compare our model to the state-of-the-art in multi-modal image translation and achieve better results for translation on challenging datasets as well as for cross-domain retrieval on realistic datasets.