Aman Tiwari


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SemEval-2023 Task 6: LegalEval - Understanding Legal Texts
Ashutosh Modi | Prathamesh Kalamkar | Saurabh Karn | Aman Tiwari | Abhinav Joshi | Sai Kiran Tanikella | Shouvik Kumar Guha | Sachin Malhan | Vivek Raghavan
Proceedings of the 17th International Workshop on Semantic Evaluation (SemEval-2023)

In populous countries, pending legal cases have been growing exponentially. There is a need for developing NLP-based techniques for processing and automatically understanding legal documents. To promote research in the area of Legal NLP we organized the shared task LegalEval - Understanding Legal Texts at SemEval 2023. LegalEval task has three sub-tasks: Task-A (Rhetorical Roles Labeling) is about automatically structuring legal documents into semantically coherent units, Task-B (Legal Named Entity Recognition) deals with identifying relevant entities in a legal document and Task-C (Court Judgement Prediction with Explanation) explores the possibility of automatically predicting the outcome of a legal case along with providing an explanation for the prediction. In total 26 teams (approx. 100 participants spread across the world) submitted systems paper. In each of the sub-tasks, the proposed systems outperformed the baselines; however, there is a lot of scope for improvement. This paper describes the tasks, and analyzes techniques proposed by various teams.

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trlX: A Framework for Large Scale Reinforcement Learning from Human Feedback
Alexander Havrilla | Maksym Zhuravinskyi | Duy Phung | Aman Tiwari | Jonathan Tow | Stella Biderman | Quentin Anthony | Louis Castricato
Proceedings of the 2023 Conference on Empirical Methods in Natural Language Processing

Reinforcement learning from human feedback (RLHF) utilizes human feedback to better align large language models with human preferences via online optimization against a learned reward model. Current RLHF paradigms rely on Proximal Policy Optimization (PPO), which quickly becomes a challenge to implement and scale up to large architectures. To address this difficulty we present the AutoRLHF library as a feature complete open-source framework for RLHF fine-tuning of models up to and exceeding 70 billion parameters. To do so we implement support for multiple types of distributed training including distributed data parallel, model sharded, as well as tensor, sequential, and pipeline parallelism. Additionally, we implement compute and memory saving features, giving AutoRLHF the flexibility to support users with a wide range of compute resources. This includes offline RL methods like Implicit Language Q Learning (ILQL) as a compute efficient alternative to PPO. We find offline fine-tuning offers competitive performance relative to online algorithms while being easier to implement, train, and scale. To evaluate our framework we train RLHF models on two separate well-known tasks using publicly available human preference data. Models trained with AutoRLHF achieve preference win-rates over baselines at rates comparable to the original works.


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Corpus for Automatic Structuring of Legal Documents
Prathamesh Kalamkar | Aman Tiwari | Astha Agarwal | Saurabh Karn | Smita Gupta | Vivek Raghavan | Ashutosh Modi
Proceedings of the Thirteenth Language Resources and Evaluation Conference

In populous countries, pending legal cases have been growing exponentially. There is a need for developing techniques for processing and organizing legal documents. In this paper, we introduce a new corpus for structuring legal documents. In particular, we introduce a corpus of legal judgment documents in English that are segmented into topical and coherent parts. Each of these parts is annotated with a label coming from a list of pre-defined Rhetorical Roles. We develop baseline models for automatically predicting rhetorical roles in a legal document based on the annotated corpus. Further, we show the application of rhetorical roles to improve performance on the tasks of summarization and legal judgment prediction. We release the corpus and baseline model code along with the paper.

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Named Entity Recognition in Indian court judgments
Prathamesh Kalamkar | Astha Agarwal | Aman Tiwari | Smita Gupta | Saurabh Karn | Vivek Raghavan
Proceedings of the Natural Legal Language Processing Workshop 2022

Identification of named entities from legal texts is an essential building block for developing other legal Artificial Intelligence applications. Named Entities in legal texts are slightly different and more fine-grained than commonly used named entities like Person, Organization, Location etc. In this paper, we introduce a new corpus of 46545 annotated legal named entities mapped to 14 legal entity types. The Baseline model for extracting legal named entities from judgment text is also developed.