Kartik Goyal


2020

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A Probabilistic Generative Model for Typographical Analysis of Early Modern Printing
Kartik Goyal | Chris Dyer | Christopher Warren | Maxwell G’Sell | Taylor Berg-Kirkpatrick
Proceedings of the 58th Annual Meeting of the Association for Computational Linguistics

We propose a deep and interpretable probabilistic generative model to analyze glyph shapes in printed Early Modern documents. We focus on clustering extracted glyph images into underlying templates in the presence of multiple confounding sources of variance. Our approach introduces a neural editor model that first generates well-understood printing phenomena like spatial perturbations from template parameters via interpertable latent variables, and then modifies the result by generating a non-interpretable latent vector responsible for inking variations, jitter, noise from the archiving process, and other unforeseen phenomena associated with Early Modern printing. Critically, by introducing an inference network whose input is restricted to the visual residual between the observation and the interpretably-modified template, we are able to control and isolate what the vector-valued latent variable captures. We show that our approach outperforms rigid interpretable clustering baselines (c.f. Ocular) and overly-flexible deep generative models (VAE) alike on the task of completely unsupervised discovery of typefaces in mixed-fonts documents.

2019

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An Empirical Investigation of Global and Local Normalization for Recurrent Neural Sequence Models Using a Continuous Relaxation to Beam Search
Kartik Goyal | Chris Dyer | Taylor Berg-Kirkpatrick
Proceedings of the 2019 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, Volume 1 (Long and Short Papers)

Globally normalized neural sequence models are considered superior to their locally normalized equivalents because they may ameliorate the effects of label bias. However, when considering high-capacity neural parametrizations that condition on the whole input sequence, both model classes are theoretically equivalent in terms of the distributions they are capable of representing. Thus, the practical advantage of global normalization in the context of modern neural methods remains unclear. In this paper, we attempt to shed light on this problem through an empirical study. We extend an approach for search-aware training via a continuous relaxation of beam search (Goyal et al., 2017b) in order to enable training of globally normalized recurrent sequence models through simple backpropagation. We then use this technique to conduct an empirical study of the interaction between global normalization, high-capacity encoders, and search-aware optimization. We observe that in the context of inexact search, globally normalized neural models are still more effective than their locally normalized counterparts. Further, since our training approach is sensitive to warm-starting with pre-trained models, we also propose a novel initialization strategy based on self-normalization for pre-training globally normalized models. We perform analysis of our approach on two tasks: CCG supertagging and Machine Translation, and demonstrate the importance of global normalization under different conditions while using search-aware training.

2017

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Differentiable Scheduled Sampling for Credit Assignment
Kartik Goyal | Chris Dyer | Taylor Berg-Kirkpatrick
Proceedings of the 55th Annual Meeting of the Association for Computational Linguistics (Volume 2: Short Papers)

We demonstrate that a continuous relaxation of the argmax operation can be used to create a differentiable approximation to greedy decoding in sequence-to-sequence (seq2seq) models. By incorporating this approximation into the scheduled sampling training procedure–a well-known technique for correcting exposure bias–we introduce a new training objective that is continuous and differentiable everywhere and can provide informative gradients near points where previous decoding decisions change their value. By using a related approximation, we also demonstrate a similar approach to sampled-based training. We show that our approach outperforms both standard cross-entropy training and scheduled sampling procedures in two sequence prediction tasks: named entity recognition and machine translation.

2016

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Bridge-Language Capitalization Inference in Western Iranian: Sorani, Kurmanji, Zazaki, and Tajik
Patrick Littell | David R. Mortensen | Kartik Goyal | Chris Dyer | Lori Levin
Proceedings of the Tenth International Conference on Language Resources and Evaluation (LREC'16)

In Sorani Kurdish, one of the most useful orthographic features in named-entity recognition – capitalization – is absent, as the language’s Perso-Arabic script does not make a distinction between uppercase and lowercase letters. We describe a system for deriving an inferred capitalization value from closely related languages by phonological similarity, and illustrate the system using several related Western Iranian languages.

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Named Entity Recognition for Linguistic Rapid Response in Low-Resource Languages: Sorani Kurdish and Tajik
Patrick Littell | Kartik Goyal | David R. Mortensen | Alexa Little | Chris Dyer | Lori Levin
Proceedings of COLING 2016, the 26th International Conference on Computational Linguistics: Technical Papers

This paper describes our construction of named-entity recognition (NER) systems in two Western Iranian languages, Sorani Kurdish and Tajik, as a part of a pilot study of “Linguistic Rapid Response” to potential emergency humanitarian relief situations. In the absence of large annotated corpora, parallel corpora, treebanks, bilingual lexica, etc., we found the following to be effective: exploiting distributional regularities in monolingual data, projecting information across closely related languages, and utilizing human linguist judgments. We show promising results on both a four-month exercise in Sorani and a two-day exercise in Tajik, achieved with minimal annotation costs.

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PanPhon: A Resource for Mapping IPA Segments to Articulatory Feature Vectors
David R. Mortensen | Patrick Littell | Akash Bharadwaj | Kartik Goyal | Chris Dyer | Lori Levin
Proceedings of COLING 2016, the 26th International Conference on Computational Linguistics: Technical Papers

This paper contributes to a growing body of evidence that—when coupled with appropriate machine-learning techniques–linguistically motivated, information-rich representations can outperform one-hot encodings of linguistic data. In particular, we show that phonological features outperform character-based models. PanPhon is a database relating over 5,000 IPA segments to 21 subsegmental articulatory features. We show that this database boosts performance in various NER-related tasks. Phonologically aware, neural CRF models built on PanPhon features are able to perform better on monolingual Spanish and Turkish NER tasks that character-based models. They have also been shown to work well in transfer models (as between Uzbek and Turkish). PanPhon features also contribute measurably to Orthography-to-IPA conversion tasks.

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Posterior regularization for Joint Modeling of Multiple Structured Prediction Tasks with Soft Constraints
Kartik Goyal | Chris Dyer
Proceedings of the Workshop on Structured Prediction for NLP

2014

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Unsupervised Word Sense Induction using Distributional Statistics
Kartik Goyal | Eduard Hovy
Proceedings of COLING 2014, the 25th International Conference on Computational Linguistics: Technical Papers

2013

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Identifying Metaphorical Word Use with Tree Kernels
Dirk Hovy | Shashank Srivastava | Sujay Kumar Jauhar | Mrinmaya Sachan | Kartik Goyal | Huying Li | Whitney Sanders | Eduard Hovy
Proceedings of the First Workshop on Metaphor in NLP

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A Structured Distributional Semantic Model : Integrating Structure with Semantics
Kartik Goyal | Sujay Kumar Jauhar | Huiying Li | Mrinmaya Sachan | Shashank Srivastava | Eduard Hovy
Proceedings of the Workshop on Continuous Vector Space Models and their Compositionality

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A Structured Distributional Semantic Model for Event Co-reference
Kartik Goyal | Sujay Kumar Jauhar | Huiying Li | Mrinmaya Sachan | Shashank Srivastava | Eduard Hovy
Proceedings of the 51st Annual Meeting of the Association for Computational Linguistics (Volume 2: Short Papers)