Shantanu Acharya
Author directory2026
Dropping the Anchor: Statistical Context Summarization for Distributed Systems via Pulsar Attention
Aryan Sood | Shantanu Acharya | Gaurav Kumar Nayak
Findings of the Association for Computational Linguistics: EMNLP 2026
Aryan Sood | Shantanu Acharya | Gaurav Kumar Nayak
Findings of the Association for Computational Linguistics: EMNLP 2026
Inference with large language models (LLMs) on long sequences is computationally expensive due to the quadratic complexity of self-attention. Distributed blockwise methods such as Star Attention reduce this cost by sharding context across hosts, but rely on prepending a static, content-blind copy of the first block to every host. We propose Pulsar Attention, which replaces the static anchor with two lightweight, content-aware components: a small attention-sink prefix that stabilizes softmax, and compact cross-block summaries built via a Max-IDF heuristic that selects chunks containing globally rare tokens. This reduces the Phase 1 per-GPU FLOPs by up to 3.3× over Star Attention while retaining an identical KV cache footprint. On RULER with Llama-3.1-8B-Instruct, Pulsar Attention outperforms Star Attention at sequence lengths up to 128K tokens and remains competitive with dense attention across most tasks, with task-dependent absolute gains of up to 4.7% over the dense baseline.
2025
SWAN: An Efficient and Scalable Approach for Long-Context Language Modeling
Krishna C Puvvada | Faisal Ladhak | Santiago Akle Serano | Cheng-Ping Hsieh | Shantanu Acharya | Somshubra Majumdar | Fei Jia | Samuel Kriman | Simeng Sun | Dima Rekesh | Boris Ginsburg
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Krishna C Puvvada | Faisal Ladhak | Santiago Akle Serano | Cheng-Ping Hsieh | Shantanu Acharya | Somshubra Majumdar | Fei Jia | Samuel Kriman | Simeng Sun | Dima Rekesh | Boris Ginsburg
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
We present SWAN, a causal Transformer architecture in the decoder-only style that generalizes robustly to sequence lengths substantially longer than those seen during training. SWAN interleaves layers without positional encodings (NoPE) and sliding-window attention layers equipped with rotary positional encodings (SWA-RoPE), and applies a dynamic scaling mechanism for attention scores during inference. Experiments demonstrate that SWAN achieves strong length extrapolation without requiring additional long-context training. In addition, SWAN is more computationally efficient than the standard Transformer architecture, resulting in lower training cost and higher inference throughput. We further demonstrate that existing pre-trained decoder-only models can be adapted to the SWAN architecture with minimal continued training, enabling extended contexts. Overall, our work presents an effective approach for scaling language models to longer contexts in a robust and efficient manner.
2019
Every Child Should Have Parents: A Taxonomy Refinement Algorithm Based on Hyperbolic Term Embeddings
Rami Aly | Shantanu Acharya | Alexander Ossa | Arne Köhn | Chris Biemann | Alexander Panchenko
Proceedings of the 57th Annual Meeting of the Association for Computational Linguistics
Rami Aly | Shantanu Acharya | Alexander Ossa | Arne Köhn | Chris Biemann | Alexander Panchenko
Proceedings of the 57th Annual Meeting of the Association for Computational Linguistics
We introduce the use of Poincaré embeddings to improve existing state-of-the-art approaches to domain-specific taxonomy induction from text as a signal for both relocating wrong hyponym terms within a (pre-induced) taxonomy as well as for attaching disconnected terms in a taxonomy. This method substantially improves previous state-of-the-art results on the SemEval-2016 Task 13 on taxonomy extraction. We demonstrate the superiority of Poincaré embeddings over distributional semantic representations, supporting the hypothesis that they can better capture hierarchical lexical-semantic relationships than embeddings in the Euclidean space.