Natwar Modani


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A Neural CRF-based Hierarchical Approach for Linear Text Segmentation
Inderjeet Nair | Aparna Garimella | Balaji Vasan Srinivasan | Natwar Modani | Niyati Chhaya | Srikrishna Karanam | Sumit Shekhar
Findings of the Association for Computational Linguistics: EACL 2023

We consider the problem of segmenting unformatted text and transcripts linearly based on their topical structure. While prior approaches explicitly train to predict segment boundaries, our proposed approach solves this task by inferring the hierarchical segmentation structure associated with the input text fragment. Given the lack of a large annotated dataset for this task, we propose a data curation strategy and create a corpus of over 700K Wikipedia articles with their hierarchical structures. We then propose the first supervised approach to generating hierarchical segmentation structures based on these annotations. Our method, in particular, is based on a neural conditional random field (CRF), which explicitly models the statistical dependency between a node and its constituent child nodes. We introduce a new data augmentation scheme as part of our model training strategy, which involves sampling a variety of node aggregations, permutations, and removals, all of which help capture fine-grained and coarse topical shifts in the data and improve model performance. Extensive experiments show that our model outperforms or achieves competitive performance when compared to previous state-of-the-art algorithms in the following settings: rich-resource, cross-domain transferability, few-shot supervision, and segmentation when topic label annotations are provided.

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Exploiting Language Characteristics for Legal Domain-Specific Language Model Pretraining
Inderjeet Nair | Natwar Modani
Findings of the Association for Computational Linguistics: EACL 2023

Pretraining large language models has resulted in tremendous performance improvement for many natural language processing (NLP) tasks. While for non-domain specific tasks, such models can be used directly, a common strategy to achieve better performance for specific domains involves pretraining these language models over domain specific data using objectives like Masked Language Modelling (MLM), Autoregressive Language Modelling, etc. While such pretraining addresses the change in vocabulary and style of language for the domain, it is otherwise a domain agnostic approach. In this work, we investigate the effect of incorporating pretraining objectives that explicitly tries to exploit the domain specific language characteristics in addition to such MLM based pretraining. Particularly, we examine two distinct characteristics associated with the legal domain and propose pretraining objectives modelling these characteristics. The proposed objectives target improvement of token-level feature representation, as well as aim to incorporate sentence level semantics. We demonstrate superiority in the performance of the models pretrained using our objectives against those trained using domain-agnostic objectives over several legal downstream tasks.


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Corpus-based Content Construction
Balaji Vasan Srinivasan | Pranav Maneriker | Kundan Krishna | Natwar Modani
Proceedings of the 27th International Conference on Computational Linguistics

Enterprise content writers are engaged in writing textual content for various purposes. Often, the text being written may already be present in the enterprise corpus in the form of past articles and can be re-purposed for the current needs. In the absence of suitable tools, authors manually curate/create such content (sometimes from scratch) which reduces their productivity. To address this, we propose an automatic approach to generate an initial version of the author’s intended text based on an input content snippet. Starting with a set of extracted textual fragments related to the snippet based on the query words in it, the proposed approach builds the desired text from these fragment by simultaneously optimizing the information coverage, relevance, diversity and coherence in the generated content. Evaluations on standard datasets shows improved performance against existing baselines on several metrics.