Sergey Nikolenko


2024

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ProConSuL: Project Context for Code Summarization with LLMs
Vadim Lomshakov | Andrey Podivilov | Sergey Savin | Oleg Baryshnikov | Alena Lisevych | Sergey Nikolenko
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing: Industry Track

We propose Project Context for Code Summarization with LLMs (ProConSuL), a new framework to provide a large language model (LLM) with precise information about the code structure from program analysis methods such as a compiler or IDE language services and use task decomposition derived from the code structure. ProConSuL builds a call graph to provide the context from callees and uses a two-phase training method (SFT + preference alignment) to train the model to use the project context. We also provide a new evaluation benchmark for C/C++ functions and a set of proxy metrics. Experimental results demonstrate that ProConSuL allows to significantly improve code summaries and reduce the number of hallucinations compared to the base model (CodeLlama-7B-instruct). We make our code and dataset available at https://github.com/TypingCat13/ProConSuL.

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Toolken+: Improving LLM Tool Usage with Reranking and a Reject Option
Konstantin Yakovlev | Sergey Nikolenko | Andrey Bout
Findings of the Association for Computational Linguistics: EMNLP 2024

The recently proposed ToolkenGPT tool learning paradigm demonstrates promising performance but suffers from two major issues: first, it cannot benefit from tool documentation, and second, it often makes mistakes in whether to use a tool at all. We introduce Toolken+ that mitigates the first problem by reranking top-k tools selected by ToolkenGPT and the second problem with a special REJECT option such that the model will generate a vocabulary token if REJECT is ranked first. We demonstrate the effectiveness of Toolken+ on multistep numerical reasoning and tool selection tasks.

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Robust AI-Generated Text Detection by Restricted Embeddings
Kristian Kuznetsov | Eduard Tulchinskii | Laida Kushnareva | German Magai | Serguei Barannikov | Sergey Nikolenko | Irina Piontkovskaya
Findings of the Association for Computational Linguistics: EMNLP 2024

Growing amount and quality of AI-generated texts makes detecting such content more difficult. In most real-world scenarios, the domain (style and topic) of generated data and the generator model are not known in advance. In this work, we focus on the robustness of classifier-based detectors of AI-generated text, namely their ability to transfer to unseen generators or semantic domains. We investigate the geometry of the embedding space of Transformer-based text encoders and show that clearing out harmful linear subspaces helps to train a robust classifier, ignoring domain-specific spurious features. We investigate several subspace decomposition and feature selection strategies and achieve significant improvements over state of the art methods in cross-domain and cross-generator transfer. Our best approaches for head-wise and coordinate-based subspace removal increase the mean out-of-distribution (OOD) classification score by up to 9% and 14% in particular setups for RoBERTa and BERT embeddings respectively. We release our code and data: https://github.com/SilverSolver/RobustATD

2023

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GEC-DePenD: Non-Autoregressive Grammatical Error Correction with Decoupled Permutation and Decoding
Konstantin Yakovlev | Alexander Podolskiy | Andrey Bout | Sergey Nikolenko | Irina Piontkovskaya
Proceedings of the 61st Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)

Grammatical error correction (GEC) is an important NLP task that is currently usually solved with autoregressive sequence-to-sequence models. However, approaches of this class are inherently slow due to one-by-one token generation, so non-autoregressive alternatives are needed. In this work, we propose a novel non-autoregressive approach to GEC that decouples the architecture into a permutation network that outputs a self-attention weight matrix that can be used in beam search to find the best permutation of input tokens (with auxiliary <ins> tokens) and a decoder network based on a step-unrolled denoising autoencoder that fills in specific tokens. This allows us to find the token permutation after only one forward pass of the permutation network, avoiding autoregressive constructions. We show that the resulting network improves over previously known non-autoregressive methods for GEC and reaches the level of autoregressive methods that do not use language-specific synthetic data generation methods. Our results are supported by a comprehensive experimental validation on the ConLL-2014 and BEA datasets and an extensive ablation study that supports our architectural and algorithmic choices.

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Efficient Grammatical Error Correction Via Multi-Task Training and Optimized Training Schedule
Andrey Bout | Alexander Podolskiy | Sergey Nikolenko | Irina Piontkovskaya
Proceedings of the 2023 Conference on Empirical Methods in Natural Language Processing

Progress in neural grammatical error correction (GEC) is hindered by the lack of annotated training data. Sufficient amounts of high-quality manually annotated data are not available, so recent research has relied on generating synthetic data, pretraining on it, and then fine-tuning on real datasets; performance gains have been achieved either by ensembling or by using huge pretrained models such as XXL-T5 as the backbone. In this work, we explore an orthogonal direction: how to use available data more efficiently. First, we propose auxiliary tasks that exploit the alignment between the original and corrected sentences, such as predicting a sequence of corrections. We formulate each task as a sequence-to-sequence problem and perform multi-task training. Second, we discover that the order of datasets used for training and even individual instances within a dataset may have important effects on the final performance, so we set out to find the best training schedule. Together, these two ideas lead to significant improvements, producing results that improve state of the art with much smaller models; in particular, we outperform the best models based on T5-XXL (11B parameters) with a BART-based model (400M parameters).

2022

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RuCCoN: Clinical Concept Normalization in Russian
Alexandr Nesterov | Galina Zubkova | Zulfat Miftahutdinov | Vladimir Kokh | Elena Tutubalina | Artem Shelmanov | Anton Alekseev | Manvel Avetisian | Andrey Chertok | Sergey Nikolenko
Findings of the Association for Computational Linguistics: ACL 2022

We present RuCCoN, a new dataset for clinical concept normalization in Russian manually annotated by medical professionals. It contains over 16,028 entity mentions manually linked to over 2,409 unique concepts from the Russian language part of the UMLS ontology. We provide train/test splits for different settings (stratified, zero-shot, and CUI-less) and present strong baselines obtained with state-of-the-art models such as SapBERT. At present, Russian medical NLP is lacking in both datasets and trained models, and we view this work as an important step towards filling this gap. Our dataset and annotation guidelines are available at https://github.com/sberbank-ai-lab/RuCCoN.

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Medical Crossing: a Cross-lingual Evaluation of Clinical Entity Linking
Anton Alekseev | Zulfat Miftahutdinov | Elena Tutubalina | Artem Shelmanov | Vladimir Ivanov | Vladimir Kokh | Alexander Nesterov | Manvel Avetisian | Andrei Chertok | Sergey Nikolenko
Proceedings of the Thirteenth Language Resources and Evaluation Conference

Medical data annotation requires highly qualified expertise. Despite the efforts devoted to medical entity linking in different languages, available data is very sparse in terms of both data volume and languages. In this work, we establish benchmarks for cross-lingual medical entity linking using clinical reports, clinical guidelines, and medical research papers. We present a test set filtering procedure designed to analyze the “hard cases” of entity linking approaching zero-shot cross-lingual transfer learning, evaluate state-of-the-art models, and draw several interesting conclusions based on our evaluation results.

2020

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Ad Lingua: Text Classification Improves Symbolism Prediction in Image Advertisements
Andrey Savchenko | Anton Alekseev | Sejeong Kwon | Elena Tutubalina | Evgeny Myasnikov | Sergey Nikolenko
Proceedings of the 28th International Conference on Computational Linguistics

Understanding image advertisements is a challenging task, often requiring non-literal interpretation. We argue that standard image-based predictions are insufficient for symbolism prediction. Following the intuition that texts and images are complementary in advertising, we introduce a multimodal ensemble of a state of the art image-based classifier, a classifier based on an object detection architecture, and a fine-tuned language model applied to texts extracted from ads by OCR. The resulting system establishes a new state of the art in symbolism prediction.

2019

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Large-Scale Transfer Learning for Natural Language Generation
Sergey Golovanov | Rauf Kurbanov | Sergey Nikolenko | Kyryl Truskovskyi | Alexander Tselousov | Thomas Wolf
Proceedings of the 57th Annual Meeting of the Association for Computational Linguistics

Large-scale pretrained language models define state of the art in natural language processing, achieving outstanding performance on a variety of tasks. We study how these architectures can be applied and adapted for natural language generation, comparing a number of architectural and training schemes. We focus in particular on open-domain dialog as a typical high entropy generation task, presenting and comparing different architectures for adapting pretrained models with state of the art results.

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AspeRa: Aspect-Based Rating Prediction Based on User Reviews
Elena Tutubalina | Valentin Malykh | Sergey Nikolenko | Anton Alekseev | Ilya Shenbin
Proceedings of the 2019 Workshop on Widening NLP

We propose a novel Aspect-based Rating Prediction model (AspeRa) that estimates user rating based on review texts for the items. It is based on aspect extraction with neural networks and combines the advantages of deep learning and topic modeling. It is mainly designed for recommendations, but an important secondary goal of AspeRa is to discover coherent aspects of reviews that can be used to explain predictions or for user profiling. We conduct a comprehensive empirical study of AspeRa, showing that it outperforms state-of-the-art models in terms of recommendation quality and produces interpretable aspects. This paper is an abridged version of our work (Nikolenko et al., 2019)