Portrait de Negar Rostamzadeh

Negar Rostamzadeh

Membre industriel associé
Chercheuse scientifique principale, Google Brain Ethical AI Team
Sujets de recherche
Apprentissage multimodal
Modèles génératifs
Vision par ordinateur

Biographie

Negar Rostamzadeh est chercheuse principale au sein de l'équipe Google Responsible AI et membre industrielle associée à Mila - Institut québécois d'intelligence artificielle. Ses recherches portent principalement sur la compréhension des implications sociales de l'apprentissage automatique et des systèmes d'évaluation, ainsi que sur le développement de systèmes d'intelligence artificielle équitables et justes.

Negar s'intéresse de près aux applications créatives de la vision par ordinateur et à leur impact sur la société et les artistes. Elle est la fondatrice et la présidente du programme de la série d'ateliers « Computer Vision for Fashion, Art, and Design », ainsi que « Ethical Considerations in Creative Applications », présentés sur les sites de Computer Vision depuis ECCV 2018 jusqu'à CVPR 2023.

Avant de rejoindre Google, Negar a travaillé comme chercheuse chez Element AI (Service Now), où elle s'est spécialisée dans l'apprentissage efficace à partir de données limitées en vision par ordinateur et dans les problèmes multimodaux.

Elle a obtenu son doctorat en 2017 à l'Université de Trente sous la supervision du professeur Nicu Sebe, en se concentrant sur les problèmes de compréhension vidéo. Elle a également passé deux ans à MILA (2015-2017), travaillant sur les mécanismes d'attention dans les vidéos, les modèles génératifs et le sous-titrage vidéo sous la direction du Prof. Aaron Courville. En 2016, elle a eu l'occasion de faire un stage au sein de l'équipe Machine Intelligence de Google.

Negar contribue activement à divers engagements communautaires au sein de la communauté de l'IA. Elle a été présidente du programme pour la série d'ateliers « Science meets Engineering of Deep Learning » à l'ICLR, FAccT et NeurIPS. Depuis 2020, elle est membre du conseil d'administration du Symposium d'IA de Montréal et, en 2019, elle a occupé le poste de présidente principale du programme. Negar est également Area Chair pour des conférences sur la vision telles que CVPR et ICCV, et a donné plusieurs keynotes dans divers ateliers et conférences.

Étudiants actuels

Alireza Dehghanpour Farashah
Maîtrise recherche - McGill
Superviseur⋅e principal⋅e :
Golnoosh Farnadi
Site web
Github

Publications

Healthsheet: Development of a Transparency Artifact for Health Datasets
Negar Rostamzadeh
Diana Mincu
Subhrajit Roy
Andrew J Smart
Lauren Wilcox
Mahima Pushkarna
Jessica Schrouff
Razvan Amironesei
Nyalleng Moorosi
Katherine Heller
Machine learning (ML) approaches have demonstrated promising results in a wide range of healthcare applications. Data plays a crucial role i… (voir plus)n developing ML-based healthcare systems that directly affect people’s lives. Many of the ethical issues surrounding the use of ML in healthcare stem from structural inequalities underlying the way we collect, use, and handle data. Developing guidelines to improve documentation practices regarding the creation, use, and maintenance of ML healthcare datasets is therefore of critical importance. In this work, we introduce Healthsheet, a contextualized adaptation of the original datasheet questionnaire [22] for health-specific applications. Through a series of semi-structured interviews, we adapt the datasheets for healthcare data documentation. As part of the Healthsheet development process and to understand the obstacles researchers face in creating datasheets, we worked with three publicly-available healthcare datasets as our case studies, each with different types of structured data: Electronic health Records (EHR), clinical trial study data, and smartphone-based performance outcome measures. Our findings from the interviewee study and case studies show 1) that datasheets should be contextualized for healthcare, 2) that despite incentives to adopt accountability practices such as datasheets, there is a lack of consistency in the broader use of these practices 3) how the ML for health community views datasheets and particularly Healthsheets as diagnostic tool to surface the limitations and strength of datasets and 4) the relative importance of different fields in the datasheet to healthcare concerns.
2022-02-26
ArXiv (preprint)
doi.org
arxiv.org
Sociotechnical Harms: Scoping a Taxonomy for Harm Reduction
Renee Shelby
Shalaleh Rismani
Kathryn Henne
AJung Moon
Negar Rostamzadeh
Paul Nicholas
N'mah Fodiatu Yilla
Jess Gallegos
Andrew J Smart
Emilio Garcia
Gurleen Virk
2022-01-01
arXiv.org (prépublication)
doi.org
Reinforced active learning for image segmentation
Arantxa Casanova
Pedro O. Pinheiro
Negar Rostamzadeh
Chris Pal
Learning-based approaches for semantic segmentation have two inherent challenges. First, acquiring pixel-wise labels is expensive and time-c… (voir plus)onsuming. Second, realistic segmentation datasets are highly unbalanced: some categories are much more abundant than others, biasing the performance to the most represented ones. In this paper, we are interested in focusing human labelling effort on a small subset of a larger pool of data, minimizing this effort while maximizing performance of a segmentation model on a hold-out set. We present a new active learning strategy for semantic segmentation based on deep reinforcement learning (RL). An agent learns a policy to select a subset of small informative image regions -- opposed to entire images -- to be labeled, from a pool of unlabeled data. The region selection decision is made based on predictions and uncertainties of the segmentation model being trained. Our method proposes a new modification of the deep Q-network (DQN) formulation for active learning, adapting it to the large-scale nature of semantic segmentation problems. We test the proof of concept in CamVid and provide results in the large-scale dataset Cityscapes. On Cityscapes, our deep RL region-based DQN approach requires roughly 30% less additional labeled data than our most competitive baseline to reach the same performance. Moreover, we find that our method asks for more labels of under-represented categories compared to the baselines, improving their performance and helping to mitigate class imbalance.
2020-01-01
ICLR (publié)
openreview.net
openreview.net
Retrieving Signals with Deep Complex Extractors
Chiheb Trabelsi
Olexa Bilaniuk
Ousmane Dia
Ying Zhang
Mirco Ravanelli
Jonathan Binas
Negar Rostamzadeh
Chris Pal
Recent advances have made it possible to create deep complex-valued neural networks. Despite this progress, many challenging learning tasks … (voir plus)have yet to leverage the power of complex representations. Building on recent advances, we propose a new deep complex-valued method for signal retrieval and extraction in the frequency domain. As a case study, we perform audio source separation in the Fourier domain. Our new method takes advantage of the convolution theorem which states that the Fourier transform of two convolved signals is the elementwise product of their Fourier transforms. Our novel method is based on a complex-valued version of Feature-Wise Linear Modulation (FiLM) and serves as the keystone of our proposed signal extraction method. We also introduce a new and explicit amplitude and phase-aware loss, which is scale and time invariant, taking into account the complex-valued components of the spectrogram. Using the Wall Street Journal Dataset, we compared our phase-aware loss to several others that operate both in the time and frequency domains and demonstrate the effectiveness of our proposed signal extraction method and proposed loss.
2019-10-21
NeurIPS.cc/2019/Workshop/Deep_Inverse (poster)
openreview.net
openreview.net
Reinforced Imitation in Heterogeneous Action Space
Konrad Żołna
Negar Rostamzadeh
Yoshua Bengio
Sungjin Ahn
Pedro O. Pinheiro
Imitation learning is an effective alternative approach to learn a policy when the reward function is sparse. In this paper, we consider a c… (voir plus)hallenging setting where an agent and an expert use different actions from each other. We assume that the agent has access to a sparse reward function and state-only expert observations. We propose a method which gradually balances between the imitation learning cost and the reinforcement learning objective. In addition, this method adapts the agent's policy based on either mimicking expert behavior or maximizing sparse reward. We show, through navigation scenarios, that (i) an agent is able to efficiently leverage sparse rewards to outperform standard state-only imitation learning, (ii) it can learn a policy even when its actions are different from the expert, and (iii) the performance of the agent is not bounded by that of the expert, due to the optimized usage of sparse rewards.
2019-04-06
ArXiv (prépublication)
arxiv.org
arxiv.org
Towards Standardization of Data Licenses: The Montreal Data License
Misha Benjamin
P. Gagnon
Negar Rostamzadeh
Chris Pal
Yoshua Bengio
Alex Shee
This paper provides a taxonomy for the licensing of data in the fields of artificial intelligence and machine learning. The paper's goal is … (voir plus)to build towards a common framework for data licensing akin to the licensing of open source software. Increased transparency and resolving conceptual ambiguities in existing licensing language are two noted benefits of the approach proposed in the paper. In parallel, such benefits may help foster fairer and more efficient markets for data through bringing about clearer tools and concepts that better define how data can be used in the fields of AI and ML. The paper's approach is summarized in a new family of data license language - \textit{the Montreal Data License (MDL)}. Alongside this new license, the authors and their collaborators have developed a web-based tool to generate license language espousing the taxonomies articulated in this paper.
2019-03-21
ArXiv (prépublication)
arxiv.org
arxiv.org
Neural Multisensory Scene Inference
Jae Hyun Lim
Pedro O. Pinheiro
Negar Rostamzadeh
Chris Pal
Sungjin Ahn
For embodied agents to infer representations of the underlying 3D physical world they inhabit, they should efficiently combine multisensory … (voir plus)cues from numerous trials, e.g., by looking at and touching objects. Despite its importance, multisensory 3D scene representation learning has received less attention compared to the unimodal setting. In this paper, we propose the Generative Multisensory Network (GMN) for learning latent representations of 3D scenes which are partially observable through multiple sensory modalities. We also introduce a novel method, called the Amortized Product-of-Experts, to improve the computational efficiency and the robustness to unseen combinations of modalities at test time. Experimental results demonstrate that the proposed model can efficiently infer robust modality-invariant 3D-scene representations from arbitrary combinations of modalities and perform accurate cross-modal generation. To perform this exploration we have also developed a novel multi-sensory simulation environment for embodied agents.
arxiv.org
Fashion-Gen: The Generative Fashion Dataset and Challenge
Negar Rostamzadeh
Seyedarian Hosseini
Thomas Boquet
Wojciech Stokowiec
Ying Zhang
Christian Jauvin
Chris Pal
We introduce a new dataset of 293,008 high definition (1360 x 1360 pixels) fashion images paired with item descriptions provided by professi… (voir plus)onal stylists. Each item is photographed from a variety of angles. We provide baseline results on 1) high-resolution image generation, and 2) image generation conditioned on the given text descriptions. We invite the community to improve upon these baselines. In this paper, we also outline the details of a challenge that we are launching based upon this dataset.
2018-06-21
ArXiv (prépublication)
arxiv.org
arxiv.org
Hierarchical Adversarially Learned Inference
Ishmael Belghazi
Sai Rajeswar
Olivier Mastropietro
Negar Rostamzadeh
Jovana Mitrovic
Aaron Courville
We propose a novel hierarchical generative model with a simple Markovian structure and a corresponding inference model. Both the generative … (voir plus)and inference model are trained using the adversarial learning paradigm. We demonstrate that the hierarchical structure supports the learning of progressively more abstract representations as well as providing semantically meaningful reconstructions with different levels of fidelity. Furthermore, we show that minimizing the Jensen-Shanon divergence between the generative and inference network is enough to minimize the reconstruction error. The resulting semantically meaningful hierarchical latent structure discovery is exemplified on the CelebA dataset. There, we show that the features learned by our model in an unsupervised way outperform the best handcrafted features. Furthermore, the extracted features remain competitive when compared to several recent deep supervised approaches on an attribute prediction task on CelebA. Finally, we leverage the model's inference network to achieve state-of-the-art performance on a semi-supervised variant of the MNIST digit classification task.
2018-02-04
ArXiv (prépublication)
openreview.net
openreview.net
Deep Complex Networks
Chiheb Trabelsi
Olexa Bilaniuk
Ying Zhang
Dmitriy Serdyuk
Sandeep Subramanian
Joao Felipe Santos
Soroush Mehri
Negar Rostamzadeh
Yoshua Bengio
Chris Pal
At present, the vast majority of building blocks, techniques, and architectures for deep learning are based on real-valued operations and re… (voir plus)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)
openreview.net
openreview.net
Deep Complex Networks
Chiheb Trabelsi
Olexa Bilaniuk
Dmitriy Serdyuk
Sandeep Subramanian
Joao Felipe Santos
Soroush Mehri
Negar Rostamzadeh
Yoshua Bengio
Chris Pal
2017-05-27
ArXiv (prépublication)
arxiv.org
arxiv.org
Deep Complex Networks
Chiheb Trabelsi
Olexa Bilaniuk
Dmitriy Serdyuk
Sandeep Subramanian
Joao Felipe Santos
Soroush Mehri
Negar Rostamzadeh
Yoshua Bengio
Chris Pal
At present, the vast majority of building blocks, techniques, and architectures for deep learning are based on real-valued operations and re… (voir plus)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 and convolutional LSTMs. 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 the TIMIT dataset. We achieve state-of-the-art performance on these audio-related tasks.
2017-05-27
ArXiv (prépublication)
arxiv.org
arxiv.org