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Koustuv Sinha

Alumni

Publications

A Lightweight Library for Energy-Based Joint-Embedding Predictive Architectures
Randall Balestriero
Megi Dervishi
David Fan
Quentin Garrido
Tushar Nagarajan
Wancong Zhang
Michael G. Rabbat
Amir Bar
We present EB-JEPA, an open-source library for learning representations and world models using Joint-Embedding Predictive Architectures (JEP… (see more)As). JEPAs learn to predict in representation space rather than pixel space, avoiding the pitfalls of generative modeling while capturing semantically meaningful features suitable for downstream tasks. Our library provides modular, self-contained implementations that illustrate how representation learning techniques developed for image-level self-supervised learning can transfer to video, where temporal dynamics add complexity, and ultimately to action-conditioned world models, where the model must additionally learn to predict the effects of control inputs. Each example is designed for single-GPU training within a few hours, making energy-based self-supervised learning accessible for research and education. We provide ablations of JEA components on CIFAR-10. Probing these representations yields 91% accuracy, indicating that the model learns useful features. Extending to video, we include a multi-step prediction example on Moving MNIST that demonstrates how the same principles scale to temporal modeling. Finally, we show how these representations can drive action-conditioned world models, achieving a 97% planning success rate on the Two Rooms navigation task. Comprehensive ablations reveal the critical importance of each regularization component for preventing representation collapse. Code is available at https://github.com/facebookresearch/eb_jepa.
V-JEPA 2: Self-Supervised Video Models Enable Understanding, Prediction and Planning
Mahmoud Assran
Adrien Bardes
David Fan
Quentin Garrido
Russell Howes
Mojtaba Komeili
Matthew J. Muckley
Ammar Rizvi
Claire Roberts
Sergio Arnaud
Abha Gejji
Ada Martin
Francois Hogan
Daniel Dugas
Piotr Bojanowski
Vasil Khalidov
Patrick Labatut
Francisco Massa … (see 13 more)
Marc Szafraniec
K. Krishnakumar
Ying Li
Xiaodong Ma
A. Chandar
Franziska Meier
Michael G. Rabbat
Fair at Meta
Mila - Québec
AI Institute
Polytechnique Montréal
A major challenge for modern AI is to learn to understand the world and learn to act largely by observation. This paper explores a self-supe… (see more)rvised approach that combines internet-scale video data with a small amount of interaction data (robot trajectories), to develop models capable of understanding, predicting, and planning in the physical world. We first pre-train an action-free joint-embedding-predictive architecture, V-JEPA 2, on a video and image dataset comprising over 1 million hours of internet video. V-JEPA 2 achieves strong performance on motion understanding (77.3 top-1 accuracy on Something-Something v2) and state-of-the-art performance on human action anticipation (39.7 recall-at-5 on Epic-Kitchens-100) surpassing previous task-specific models. Additionally, after aligning V-JEPA 2 with a large language model, we demonstrate state-of-the-art performance on multiple video question-answering tasks at the 8 billion parameter scale (e.g., 84.0 on PerceptionTest, 76.9 on TempCompass). Finally, we show how self-supervised learning can be applied to robotic planning tasks by post-training a latent action-conditioned world model, V-JEPA 2-AC, using less than 62 hours of unlabeled robot videos from the Droid dataset. We deploy V-JEPA 2-AC zero-shot on Franka arms in two different labs and enable picking and placing of objects using planning with image goals. Notably, this is achieved without collecting any data from the robots in these environments, and without any task-specific training or reward. This work demonstrates how self-supervised learning from web-scale data and a small amount of robot interaction data can yield a world model capable of planning in the physical world.
Multi-Modal Language Models as Text-to-Image Model Evaluators
Jiahui Chen
Candace Ross
Melissa Hall
Adriana Romero
Scaling Language-Free Visual Representation Learning
David Fan
Shengbang Tong
Jiachen Zhu
Zhuang Liu
Xinlei Chen
Michael G. Rabbat
Amir Bar
Saining Xie
MetaMorph: Multimodal Understanding and Generation via Instruction Tuning
Shengbang Tong
David Fan
Jiachen Zhu
Yunyang Xiong
Xinlei Chen
Michael G. Rabbat
Saining Xie
Zhuang Liu
In this work, we propose Visual-Predictive Instruction Tuning (VPiT) - a simple and effective extension to visual instruction tuning that en… (see more)ables a pretrained LLM to quickly morph into an unified autoregressive model capable of generating both text and visual tokens. VPiT teaches an LLM to predict discrete text tokens and continuous visual tokens from any input sequence of image and text data curated in an instruction-following format. Our empirical investigation reveals several intriguing properties of VPiT: (1) visual generation ability emerges as a natural byproduct of improved visual understanding, and can be unlocked efficiently with a small amount of generation data; (2) while we find understanding and generation to be mutually beneficial, understanding data contributes to both capabilities more effectively than generation data. Building upon these findings, we train our MetaMorph model and achieve competitive performance on both visual understanding and generation. In visual generation, MetaMorph can leverage the world knowledge and reasoning abilities gained from LLM pretraining, and overcome common failure modes exhibited by other generation models. Our results suggest that LLMs may have strong"prior"vision capabilities that can be efficiently adapted to both visual understanding and generation with a relatively simple instruction tuning process.
Controlling Multimodal LLMs via Reward-guided Decoding
The Curious Case of Absolute Position Embeddings
Transformer language models encode the notion of word order using positional information. Most commonly, this positional information is repr… (see more)esented by absolute position embeddings (APEs), that are learned from the pretraining data. However, in natural language, it is not absolute position that matters, but relative position, and the extent to which APEs can capture this type of information has not been investigated. In this work, we observe that models trained with APE over-rely on positional information to the point that they break-down when subjected to sentences with shifted position information. Specifically, when models are subjected to sentences starting from a non-zero position (excluding the effect of priming), they exhibit noticeably degraded performance on zero to full-shot tasks, across a range of model families and model sizes. Our findings raise questions about the efficacy of APEs to model the relativity of position information, and invite further introspection on the sentence and word order processing strategies employed by these models.
Masked Language Modeling and the Distributional Hypothesis: Order Word Matters Pre-training for Little
Robin Jia
Dieuwke Hupkes
Adina Williams
Douwe Kiela
A possible explanation for the impressive performance of masked language model (MLM) pre-training is that such models have learned to repres… (see more)ent the syntactic structures prevalent in classical NLP pipelines. In this paper, we propose a different explanation: MLMs succeed on downstream tasks almost entirely due to their ability to model higher-order word co-occurrence statistics. To demonstrate this, we pre-train MLMs on sentences with randomly shuffled word order, and show that these models still achieve high accuracy after fine-tuning on many downstream tasks—including tasks specifically designed to be challenging for models that ignore word order. Our models perform surprisingly well according to some parametric syntactic probes, indicating possible deficiencies in how we test representations for syntactic information. Overall, our results show that purely distributional information largely explains the success of pre-training, and underscore the importance of curating challenging evaluation datasets that require deeper linguistic knowledge.
Improving Reproducibility in Machine Learning Research (A Report from the NeurIPS 2019 Reproducibility Program)
Philippe Vincent-Lamarre
Vincent Larivière
Alina Beygelzimer
Florence d'Alché-Buc
Emily Fox
One of the challenges in machine learning research is to ensure that presented and published results are sound and reliable. Reproducibility… (see more), that is obtaining similar results as presented in a paper or talk, using the same code and data (when available), is a necessary step to verify the reliability of research findings. Reproducibility is also an important step to promote open and accessible research, thereby allowing the scientific community to quickly integrate new findings and convert ideas to practice. Reproducibility also promotes the use of robust experimental workflows, which potentially reduce unintentional errors. In 2019, the Neural Information Processing Systems (NeurIPS) conference, the premier international conference for research in machine learning, introduced a reproducibility program, designed to improve the standards across the community for how we conduct, communicate, and evaluate machine learning research. The program contained three components: a code submission policy, a community-wide reproducibility challenge, and the inclusion of the Machine Learning Reproducibility checklist as part of the paper submission process. In this paper, we describe each of these components, how it was deployed, as well as what we were able to learn from this initiative.
A Simple and Effective Model for Multi-Hop Question Generation
Jimmy Lei Ba
Jamie Ryan Kiros
Geoffrey E Hin-602
Peter W. Battaglia
Jessica Blake
Chandler Hamrick
Vic-613 tor Bapst
Alvaro Sanchez
Vinicius Zambaldi
M. Malinowski
Andrea Tacchetti
David Raposo
Tom B. Brown
Benjamin Mann
Nick Ryder
Melanie Subbiah
Jared Kaplan
Prafulla Dhariwal
Arvind Neelakantan
Pranav Shyam … (see 72 more)
Girish Sastry
William L. Hamilton
Clutrr
Nitish Srivastava
Geoffrey Hinton
Alex Krizhevsky
Ilya Sutskever
Ruslan Salakhutdinov. 2014
Gabriel Stanovsky
Julian Michael
Luke Zettlemoyer
Dan Su
Yan Xu
Wenliang Dai
Ziwei Ji
Tiezheng Yu
Minghao Tu
Kevin Huang
Guangtao Wang
Jing Huang
Ashish Vaswani
Noam M. Shazeer
Niki Parmar
Jakob Uszkoreit
Llion Jones
Aidan N. Gomez
Łukasz Kaiser
Illia Polosukhin. 2017
Attention
Petar Veliˇckovi´c
Guillem Cucurull
Arantxa Casanova
Adriana Romero
Pietro Lio’
Johannes Welbl
Pontus Stenetorp
Yonghui Wu
Mike Schuster
Quoc Zhifeng Chen
Mohammad Le
Wolfgang Norouzi
Macherey
M. Krikun
Yuan Cao
Qin Gao
William W. Cohen
Jianxing Yu
Xiaojun Quan
Qinliang Su
Jian Yin
Yuyu Zhang
Hanjun Dai
Zornitsa Kozareva
Cheng Zhao
Chenyan Xiong
Corby Rosset
Xia
Paul Song
Bennett Saurabh
Tiwary
Yao Zhao
Xiaochuan Ni
Yuanyuan Ding
Qingyu Zhou
Nan Yang
Furu Wei
Chuanqi Tan
Previous research on automated question gen-001 eration has almost exclusively focused on gen-002 erating factoid questions whose answers ca… (see more)n 003 be extracted from a single document. How-004 ever, there is an increasing interest in develop-005 ing systems that are capable of more complex 006 multi-hop question generation (QG), where an-007 swering the question requires reasoning over 008 multiple documents. In this work, we pro-009 pose a simple and effective approach based on 010 the transformer model for multi-hop QG. Our 011 approach consists of specialized input repre-012 sentations, a supporting sentence classification 013 objective, and training data weighting. Prior 014 work on multi-hop QG considers the simpli-015 fied setting of shorter documents and also ad-016 vocates the use of entity-based graph struc-017 tures as essential ingredients in model design. 018 On the contrary, we showcase that our model 019 can scale to the challenging setting of longer 020 documents as input, does not rely on graph 021 structures, and substantially outperforms the 022 state-of-the-art approaches as measured by au-023 tomated metrics and human evaluation. 024
Measuring Systematic Generalization in Neural Proof Generation with Transformers
Nicolas Gontier
Christopher Pal
We are interested in understanding how well Transformer language models (TLMs) can perform reasoning tasks when trained on knowledge encoded… (see more) in the form of natural language. We investigate their systematic generalization abilities on a logical reasoning task in natural language, which involves reasoning over relationships between entities grounded in first-order logical proofs. Specifically, we perform soft theorem-proving by leveraging TLMs to generate natural language proofs. We test the generated proofs for logical consistency, along with the accuracy of the final inference. We observe length-generalization issues when evaluated on longer-than-trained sequences. However, we observe TLMs improve their generalization performance after being exposed to longer, exhaustive proofs. In addition, we discover that TLMs are able to generalize better using backward-chaining proofs compared to their forward-chaining counterparts, while they find it easier to generate forward chaining proofs. We observe that models that are not trained to generate proofs are better at generalizing to problems based on longer proofs. This suggests that Transformers have efficient internal reasoning strategies that are harder to interpret. These results highlight the systematic generalization behavior of TLMs in the context of logical reasoning, and we believe this work motivates deeper inspection of their underlying reasoning strategies.
A Hierarchical Neural Attention-based Text Classifier
Jackie Chi Kit Cheung
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.