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I am a postdoctoral researcher at CSAIL-MIT in the group of prof. T. Jaakkola and prof. R. Barzilay. I am part of the AI Cures initiative, MLPDS consortium and the Darpa AMD project.

Previously I obtained my PhD from the Data Analytics Lab at ETH Zurich under the supervision of prof. Thomas Hofmann.


Research Interests

I am broadly interested in representation learning for text, graphs or images through statistical or geometric models that could be devised and understood in a mathematically principled and elegant manner. In particular, I believe in leveraging non-Euclidean geometries in Machine Learning to overcome some of the current difficulties in graph representation learning and generation. I have explored finding and learning latent hierarchical structures in data via hyperbolic geometry, as well as combining optimal transport and graph neural networks for better models that deal with graphs. I am currently applying my models to problems related to computational chemistry such as drug discovery.


Research Publications


Checkout the Slides and Blog summarizing some of my recent work.
I am always happy to give talks about any of the research topics in my publications. Please contact me.


Featured Publications






Optimal Transport Graph Neural Networks


Gary Bécigneul*, Octavian-Eugen Ganea*, Benson Chen*, Regina Barzilay, Tommi Jaakkola

Under review.

[Paper] [Slides] [Data + Code]



Hyperbolic Neural Networks


Octavian-Eugen Ganea*, Gary Bécigneul*, Thomas Hofmann.

Full paper @ NeurIPS 2018: Conference on Neural Information Processing Systems.


Spotlight (top 4% of all submitted papers).

[Paper] [Video] [Poster] [BLOG] [Data + Code]



Deep Joint Entity Disambiguation with Local Neural Attention


Octavian-Eugen Ganea, Thomas Hofmann.

Full paper @ EMNLP 2017: Conference on Empirical Methods in Natural Language Processing.

[PDF] [Slides] [Poster] [Data + Code]



Hyperbolic Entailment Cones for Learning Hierarchical Embeddings


Octavian-Eugen Ganea, Gary Bécigneul, Thomas Hofmann.

Full paper @ ICML 2018: International Conference on Machine Learning. Oral talk.

[PDF] [Slides] [Poster] [Data + Code]






All Publications






Constant Curvature Graph Convolutional Networks


Gregor Bachmann, Gary Bécigneul, Octavian-Eugen Ganea

Full paper @ ICML 2020: International Conference on Machine Learning.

[Paper] [Slides] [Blog post]



Hierarchical Image Classification using Entailment Cone Embeddings


Ankit Dhall, Anastasia Makarova, Octavian-Eugen Ganea, Dario Pavllo, Michael Greeff, Andreas Krause

Paper @ DiffCVML 2020: Intl. Workshop on Differential Geometry in Computer Vision and Machine Learning

[Paper] [Slides] [Blog post] [Code + Data]



Computationally Tractable Riemannian Manifolds for Graph Embeddings


Calin Cruceru, Gary Bécigneul, Octavian-Eugen Ganea

Under review

[Paper]



Mixed-curvature Variational Autoencoders


Ondrej Skopek, Octavian-Eugen Ganea, Gary Bécigneul.

Full paper @ ICLR 2020: International Conference on Learning Representations.

[Paper] [Blog post] [Code + Data] [Slides + Video]



Breaking the Softmax Bottleneck via Learnable Monotonic Pointwise Non-linearities


Octavian-Eugen Ganea, Sylvain Gelly, Gary Bécigneul, Aliaksei Severyn.

Full paper @ ICML 2019: International Conference on Machine Learning.

[Paper] [Slides]



Poincaré GloVe: Hyperbolic Word Embeddings


Alexandru Tifrea*, Gary Bécigneul*, Octavian-Eugen Ganea*. (equal contribution)

Full paper @ ICLR 2019: International Conference on Learning Representations.

[Paper] [Blog] [Data + Code] [Poster]



Riemannian Adaptive Optimization Methods


Gary Bécigneul, Octavian-Eugen Ganea

Full paper @ ICLR 2019: International Conference on Learning Representations.

[PDF] [External Code] [Poster]



End-to-end Neural Entity Linking


Nikolaos Kolitsas*, Octavian-Eugen Ganea*, Thomas Hofmann.

Full paper @ CoNLL 2018: Conference on Natural Language Learning.

[PDF] [Data + Code]



Probabilistic Bag-Of-Hyperlinks Model for Entity Linking


Octavian-Eugen Ganea, Marina Ganea, Aurelien Lucchi, Carsten Eickhoff, Thomas Hofmann.

Full paper @ WWW 2016: International World Wide Web Conference. Oral talk.

[PDF] [Slides] [Poster] [Data + Code] [Online system (Gerbil - D2KB)] [Comparison with existing systems (Jan 2018)]



Learning and Evaluating Sparse Interpretable Sentence Embeddings


Valentin Trifonov, Octavian-Eugen Ganea, Anna Potapenko, Thomas Hofmann.

Paper @ EMNLP'18 Workshop BlackboxNLP: Analyzing and Interpreting Neural Networks for NLP. 2018.

[PDF]



Property Prediction for 2-Molecule Mixtures


Allison Tam, Octavian-Eugen Ganea, Gary Bécigneul, Regina Barzilay

AI Powered Drug Discovery and Manufacturing Conference, Cambridge MA 2020



Neural Multi-Step Reasoning for Question Answering on Semi-Structured Tables


Till Haug, Octavian-Eugen Ganea, Paulina Grnarova .

Short paper @ ECIR 2018: European Conference on Information Retrieval.

[PDF] [Slides]



Web2Text: Deep Structured Boilerplate Removal


Thijs Vogels, Octavian-Eugen Ganea, Carsten Eickhoff .

Long paper @ ECIR 2018: European Conference on Information Retrieval.

[PDF] [Slides] [Source Code]

Awards

2010 - Excellence scholarship - Dinu Patriciu foundation (Romania) - for master studies at EPFL
2009 - 1st prize - International Mathematical Contest for University Students IMC (www.imc-math.org) - the equivalent of IMO for BSc students
2008 - Gold Medal - South Eastern Mathematical Olympiad for University Students -- SEEMOUS - Athens, Greece
2008 - 2nd prize - International Mathematical Contest for University Students IMC (www.imc-math.org)
2007 - 2nd prize - International Mathematical Contest for University Students IMC (www.imc-math.org)
2007 - Silver Medal - South Eastern Mathematical Olympiad for University Students -- SEEMOUS - Cyprus
2008, 2009 - Honorable Mention - CM programming contest, SouthEastern European Region (http://www.acm.ro/)
2005 - Silver Medal (3 rd place) - Tuymada International Olympiad in Mathematics, Yakutsk, Russia
2005 - Silver Medal - Balkan Mathematical Olympiad -- Iasi, Romania
2001 to 2006 (every year) - one of the first 7 places every year at National Mathematical Olympiad, Romania
2013 - Top 5% in Google Code Jam programming contest

Invited Talks

July 2020: Georgia Institute of Technology, host: Le Song
July 2020: Northeastern University, hosts: Tina Eliassi-Rad, Dmitri Krioukov, Rose Yu
April 2020: Machine Learning for Pharmaceutical Discovery and Synthesis Consortium, https://mlpds.mit.edu/
March 2020: IBM Global Business Services, host: Lucia Stavarache
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February 2020: University of Massachusetts Amherst, host: Andrew McCallum



January 2020: Relational.ai, host: Nikos Vasilakis

October 2019: Aggregate Intellect - https://aisc.ai.science, host: Amir Feizpour
October 2019: MIT - Massachusetts Institute of Technology, prof. Tommi Jaakkola’s group
October 2018: Google Brain, Zurich, host: Sylvain Gelly
April 2018: ETH Zurich, Machine Learning Seminar
May 2017: Google Research, Mountain View, California
March 2017: ETH Zurich, Machine Learning Seminar

Supervised theses

I proposed and (co-)supervised a number of MSc and BSc theses projects (6 months) for the following students at ETH Zurich, some resulting in research publications (see above):
Bachmann Gregor: Constant Curvature Graph Neural Networks, (paper @ICML'20)
MSc thesis (jointly with Gary Becigneul), ETH, March - September 2019
Andreas Bloch: Mixed-curvature Recommender Systems,
MSc thesis (jointly with Gary Becigneul), ETH, March - September 2019
Ondrej Skopek: Mixed-curvature Variational Autoencoders, (paper @ICLR'20)
MSc thesis (jointly with Gary Becigneul), ETH, March - September 2019
Ankit Dhall: Hierarchical Image Captioning using Entailment Cone Representations, (paper @DiffCVML'20)
MSc thesis (jointly with Andreas Krause and Anastasia Makarova), ETH, March - September 2019
Calin Cruceru: Matrix Graph Embeddings, (paper submission)
MSc thesis (jointly with Gary Becigneul), ETH, April - October 2019
Philipp Wirth: Language Models with External Advisers,
MSc thesis (jointly with Gary Becigneul), ETH, March - September 2019
Jovan Andonov: Neural Ordinary Differential Equations for Language Modeling,
MSc thesis (jointly with Gary Becigneul and Paulina Grnarova), ETH, March - September 2019
Alexandru Tifrea: Hyperbolic Word Embeddings, (paper @ ICLR'19)
MSc thesis (jointly with Gary Becigneul), ETH, April - October 2018
Kolitsas Nikolaos: End-to-end Neural Entity Linking, (paper @ CONLL'18)
MSc thesis, ETH, October 2017 - April 2018
Junlin Yao: Detecting Medication and Adverse Drug Events from Electronic Health Records,
MSc thesis (jointly with Carsten Eickhoff), ETH, September 2017 - March 2018
Igor Petrovski: Hyperbolic Sentence Embeddings,
MSc thesis (jointly with Gary Becigneul), ETH, October 2017 - April 2018
Valentin Trivonov: Sparse and Interpretable Embeddings, (paper @ EMNLP'18 Workshop)
MSc thesis (jointly supervised with Anna Potapenko), ETH, December 2017 - May 2018
Andreas Hess: Reinforcement Learning for Question Answering with Semi-structured Tables,
MSc thesis, ETH, December 2016 - May 2017
Yifan Su: Deep Structured Prediction for Joint Entity Linking and Coreference Resolution,
MSc thesis (jointly supervised with Aurelien Lucchi), ETH, July - December 2016
Till Haug: Convolutional and Recursive Neural Networks for Question Answering on Semi-structured Tables , (paper @ ECIR'18)
BSc thesis (jointly supervised with Paulina Grnarova), ETH, August 2016 - January 2017
Severin Bahman: Memory Networks for Entity Linking,
Research project (jointly supervised with Aurelien Lucchi), ETH, March - July 2016
Andreas Georgiadis: Learning Sentence and Entity Representations for Question Answering,
Research project (jointly supervised with Aurelien Lucchi), ETH, March - July 2016
Thijs Vogels: Structured Prediction for Web Page Content Extraction, (paper @ ECIR'18)
Research project (jointly supervised with Carsten Eickhoff), ETH, Sep 2015 - May 2016
Monteiro Freire Ribeiro Joao Pedro: Unsupervised Knowledge Base Fact Prediction using Matrix Word Embeddings,
BSc thesis (jointly supervised with Paulina Grnarova), ETH, Nov 2015 - May 2016

Community Service

Co-founder of OpenConsulting.AI, a free AI consulting platform for societal non-profit projects.
Conference Reviewer: NeurIPS 2020, ICML 2020, NeurIPS 2019, AAAI 2020, ACL 2018, EMNLP 2019, EMNLP 2018.

Besides Research

Completed the longest via ferrata in Switzerland (Leukerbad) - difficulty level K5-6
video
Climbed 10 four-thousand meter summits.
Videos: Zinalrothorn (4221m),    Mönch (4107m),    Mont Blanc traverse (via 3 monts),    Dufourspitze (4634m)
Finished 6 mountain and 1 road marathons.
Member of Forbes "30 under 30", Romania’s 2013 edition