Maharshi Gor

Selected Publications

1. NeurIPS 2022

   Toward Efficient Robust Training against Union of L_p Threat Models

   Gaurang Sriramanan, Maharshi Gor, and Soheil Feizi

   In Advances in Neural Information Processing Systems 2022

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   The overwhelming vulnerability of deep neural networks to carefully crafted perturbations known as adversarial attacks has led to the development of various training techniques to produce robust models. While the primary focus of existing approaches has been directed toward addressing the worst-case performance achieved under a single-threat model, it is imperative that safety-critical systems are robust with respect to multiple threat models simultaneously. Existing approaches that address worst-case performance under the union of such threat models (e.g., \ell_∞, \ell_2, \ell_1) either utilize adversarial training methods that require multi-step attacks which are computationally expensive in practice, or rely upon fine-tuning of pre-trained models that are robust with respect to a single-threat model. In this work, we show that by carefully choosing the objective function used for robust training, it is possible to achieve similar, or even improved worst-case performance over a union of threat models while utilizing only single-step attacks during the training, thereby achieving a significant reduction in computational resources necessary for training. Furthermore, prior work showed that adversarial training against the \ell_1 threat model is relatively difficult, to the extent that even multi-step adversarially trained models were shown to be prone to gradient-masking and catastrophic over-fitting. However, our proposed method—when applied on the \ell_1 threat model specifically—enables us to obtain the first \ell_1 robust model trained solely with single-step adversarial attacks. Finally, to demonstrate the merits of our approach, we utilize a modern set of attack evaluations to better estimate the worst-case performance under the considered union of threat models.

   @inproceedings{sriramanan:gor:feizi-neurips2022,
     abbr = {NeurIPS},
     bibtex_show = {true},
     title = {Toward Efficient Robust Training against Union of L<sub>p</sub> Threat Models},
     author = {Sriramanan, Gaurang and Gor, Maharshi and Feizi, Soheil},
     booktitle = {Advances in Neural Information Processing Systems},
     year = {2022},
     location = {New Orleans, LA},
     html = {https://openreview.net/forum?id=6qdUJblMHqy},
     selected = {true}
   }

2. EMNLP 2021

   MATE: Multi-view Attention for Table Transformer Efficiency

   Julian Martin Eisenschlos, Maharshi Gor, Thomas Müller, and William Weston Cohen

   In Empirical Methods in Natural Language Processing 2021

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   This work presents a sparse-attention Transformer architecture for modeling documents that contain large tables. Tables are ubiquitous on the web, and are rich in information. However, more than 20% of relational tables on the web have 20 or more rows (Cafarella et al., 2008), and these large tables present a challenge for current Transformer models, which are typically limited to 512 tokens. Here we propose MATE, a novel Transformer architecture designed to model the structure of web tables. MATE uses sparse attention in a way that allows heads to efficiently attend to either rows or columns in a table. This architecture scales linearly with respect to speed and memory, and can handle documents containing more than 8000 tokens with current accelerators. MATE also has a more appropriate inductive bias for tabular data, and sets a new state-of-the-art for three table reasoning datasets. For HybridQA (Chen et al., 2020b), a dataset that involves large documents containing tables, we improve the best prior result by 19 points.

   @inproceedings{eisenschlos2021mate,
     abbr = {EMNLP},
     bibtex_show = {true},
     title = {MATE: Multi-view Attention for Table Transformer Efficiency},
     author = {Eisenschlos, Julian Martin and Gor, Maharshi and M{\"u}ller, Thomas and Cohen, William Weston},
     booktitle = {Empirical Methods in Natural Language Processing},
     publisher = {Association for Computational Linguistics,},
     year = {2021},
     location = {Punta Cana},
     html = {https://arxiv.org/pdf/2109.04312.pdf},
     selected = {true}
   }

3. EMNLP 2021

   Toward Deconfounding the Influence of Entity Demographics for Question Answering Accuracy

   Maharshi Gor, Kellie Webster, and Jordan Boyd-Graber

   In Empirical Methods in Natural Language Processing 2021

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   The goal of question answering (QA) is to answer any question. However, major QA datasets have skewed distributions over gender, profession, and nationality. Despite that skew, model accuracy analysis reveals little evidence that accuracy is lower for people based on gender or nationality; instead, there is more variation on professions (question topic). But QA’s lack of representation could itself hide evidence of bias, necessitating QA datasets that better represent global diversity.

   @inproceedings{Gor:Webster:Boyd-Graber-2021,
     abbr = {EMNLP},
     bibtex_show = {true},
     title = {Toward Deconfounding the Influence of Entity Demographics for Question Answering Accuracy},
     author = {Gor, Maharshi and Webster, Kellie and Boyd-Graber, Jordan},
     booktitle = {Empirical Methods in Natural Language Processing},
     publisher = {Association for Computational Linguistics,},
     month = nov,
     year = {2021},
     location = {Punta Cana},
     html = {https://arxiv.org/pdf/2104.07571.pdf},
     selected = {true}
   }