Petros Karypis
Author directory2026
How Calibration Content Shapes Attention-Based Reranking
Petros Karypis | Hossein Rajaby Faghihi | Peter Chen | Rui Zhu | Noveen Sachdeva | Yan Zhu | Julian McAuley
Findings of the Association for Computational Linguistics: EMNLP 2026
Petros Karypis | Hossein Rajaby Faghihi | Peter Chen | Rui Zhu | Noveen Sachdeva | Yan Zhu | Julian McAuley
Findings of the Association for Computational Linguistics: EMNLP 2026
Attention-based rerankers score documents by aggregating query-to-document attention and subtracting a null-query calibration pass to remove positional and structural bias. Although widely used, this calibration assumes that the null pass is independent of document relevance. We show that modern prompt content, e.g. constraints, instructions, personas, and demonstrations can violate this assumption when it enters the scoring readout, making the null pass relevance-aware rather than null. Through a three-pass decomposition, we find that calibration helps when the null-pass footprint is relevance-agnostic bias, but hurts when it is relevance-tracking signal: short shared constraints survive calibration, whereas long per-query instructions inject signal that subtraction destroys. We propose interpolated null calibration, a training-free modification that controls how much instruction content enters the null baseline. It recovers attention-based reranking on instruction-heavy tasks where standard calibration fails, while preserving calibration’s benefits when the null pass remains relevance-agnostic. On instruction heavy tasks, the recovered rankings surpass generative rerankers such as RankGPT. We also show that in-context demonstrations improve attention-based reranking with little calibration interference, since demonstrations act only through the query pass and leave the null pass unchanged.
2024
Extending Input Contexts of Language Models through Training on Segmented Sequences
Petros Karypis | Julian McAuley | George Karypis
Findings of the Association for Computational Linguistics: NAACL 2024
Petros Karypis | Julian McAuley | George Karypis
Findings of the Association for Computational Linguistics: NAACL 2024
Effectively training language models on longinputs poses many technical challenges. As acost consideration, languages models are pre-trained on a fixed sequence length before beingadapted to longer sequences. We explore var-ious methods for adapting models to longerinputs by training on segmented sequences andan interpolation-based method for extendingabsolute positional embeddings. We developa training procedure to extend the input con-text size of pretrained models with no architec-tural changes and no additional memory coststhan training on the original input lengths. Bysub-sampling segments from long inputs whilemaintaining their original position the model isable to learn new positional interactions. Ourmethod benefits both models trained with abso-lute positional embeddings, by extending theirinput contexts, as well as popular relative posi-tional embedding methods showing a reducedperplexity on sequences longer than they weretrained on. We demonstrate our method canextend input contexts by a factor of 4× whileimproving perplexity.
Fine-Tuning Language Models on Multiple Datasets for Citation Intention Classification
Zeren Shui | Petros Karypis | Daniel S. Karls | Mingjian Wen | Saurav Manchanda | Ellad B. Tadmor | George Karypis
Findings of the Association for Computational Linguistics: EMNLP 2024
Zeren Shui | Petros Karypis | Daniel S. Karls | Mingjian Wen | Saurav Manchanda | Ellad B. Tadmor | George Karypis
Findings of the Association for Computational Linguistics: EMNLP 2024
Citation intention Classification (CIC) tools classify citations by their intention (e.g., background, motivation) and assist readers in evaluating the contribution of scientific literature. Prior research has shown that pretrained language models (PLMs) such as SciBERT can achieve state-of-the-art performance on CIC benchmarks. PLMs are trained via self-supervision tasks on a large corpus of general text and can quickly adapt to CIC tasks via moderate fine-tuning on the corresponding dataset. Despite their advantages, PLMs can easily overfit small datasets during fine-tuning. In this paper, we propose a multi-task learning (MTL) framework that jointly fine-tunes PLMs on a dataset of primary interest together with multiple auxiliary CIC datasets to take advantage of additional supervision signals. We develop a data-driven task relation learning (TRL) method that controls the contribution of auxiliary datasets to avoid negative transfer and expensive hyper-parameter tuning. We conduct experiments on three CIC datasets and show that fine-tuning with additional datasets can improve the PLMs’ generalization performance on the primary dataset. PLMs fine-tuned with our proposed framework outperform the current state-of-the-art models by 7% to 11% on small datasets while aligning with the best-performing model on a large dataset.