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Naoaki Okazaki

33 accepted papers

2026

Aligning Tree-Search Policies with Fixed Token Budgets in Test-Time Scaling of LLMs

ICML 2026poster

Tree-search decoding is an effective form of test-time scaling for large language models (LLMs), but real-world deployment imposes a fixed per-query token budget that varies across settings. Existing tree-search policies are largely budget-agnostic, treating the budget as a termination condition, wh…

Cited by 0SourceScholar
2026

Beyond Perplexity: UTF-8 Validity in Byte-aware Language Models

ICML 2026poster

Byte-level tokenization enables language models to handle any Unicode input, but models can generate invalid UTF-8 sequences when encountering rare or unseen characters. We investigate the relationship between training scale and UTF-8 generation reliability with a 355M parameter model trained on 80B…

Cited by 0SourceScholar
2026

From Correspondence to Actions: Human-Like Multi-Image Spatial Reasoning in Multi-modal Large Language Models

ICML 2026poster

While multimodal large language models (MLLMs) have made substantial progress in single-image spatial reasoning, multi-image spatial reasoning, which requires integration of information from multiple viewpoints, remains challenging. Cognitive studies suggest that humans address such tasks through tw…

Cited by 0SourceScholar
2026

Rewriting Pre-Training Data Boosts LLM Performance in Math and Code

ICLR 2026poster

The performance of large language models (LLMs) in program synthesis and mathematical reasoning is fundamentally limited by the quality of their pre-training corpora. We introduce two openly licensed pre-training datasets, released under the Llama 3.3 Community License, that significantly enhance…

Cited by 0SourcecodeScholar
2026

Stopping Computation for Converged Tokens in Masked Diffusion-LM Decoding

ICLR 2026poster

Masked Diffusion Language Models generate sequences via iterative sampling that progressively unmasks tokens. However, they still recompute the attention and feed-forward blocks for every token position at every step---even when many unmasked tokens are essentially fixed, resulting in substantial wa…

Cited by 0SourceScholar
2025

Constructing Multimodal Datasets from Scratch for Rapid Development of a Japanese Visual Language Model

NAACL 2025system demonstrations

To develop high-performing Visual Language Models (VLMs), it is essential to prepare multimodal resources, such as image-text pairs, interleaved data, and instruction data. While multimodal resources for English are abundant, there is a significant lack of corresponding resources for non-English lan…

2025

HMoE: Heterogeneous Mixture of Experts for Language Modeling

EMNLP 2025

Mixture of Experts (MoE) offers remarkable performance and computational efficiency by selectively activating subsets of model parameters. Traditionally, MoE models use homogeneous experts, each with identical capacity. However, varying complexity in input data necessitates experts with diverse capa

2025

Sampling-based Pseudo-Likelihood for Membership Inference Attacks

ACL 2025finding

Large Language Models (LLMs) are trained on large-scale web data, which makes it difficult to grasp the contribution of each text. This poses the risk of leaking inappropriate data such as benchmarks, personal information, and copyrighted texts in the training data. Membership Inference Attacks (MIA…

2025

Social Bias Evaluation for Large Language Models Requires Prompt Variations

EMNLP 2025

Warning: This paper contains examples of stereotypes and biases. Large Language Models (LLMs) exhibit considerable social biases, and various studies have tried to evaluate and mitigate these biases accurately. Previous studies use downstream tasks to examine the degree of social biases for evaluati

2024

Building a Japanese Document-Level Relation Extraction Dataset Assisted by Cross-Lingual Transfer

COLING 2024main

Document-level Relation Extraction (DocRE) is the task of extracting all semantic relationships from a document. While studies have been conducted on English DocRE, limited attention has been given to DocRE in non-English languages. This work delves into effectively utilizing existing English resour…

Cited by 1SourcePDFScholar
2024

Controlled Generation with Prompt Insertion for Natural Language Explanations in Grammatical Error Correction

COLING 2024main

In Grammatical Error Correction (GEC), it is crucial to ensure the user’s comprehension of a reason for correction. Existing studies present tokens, examples, and hints for corrections, but do not directly explain the reasons in natural language. Although methods that use Large Language Models (LLMs…

2024

Evaluating Gender Bias of Pre-trained Language Models in Natural Language Inference by Considering All Labels

COLING 2024main

Discriminatory gender biases have been found in Pre-trained Language Models (PLMs) for multiple languages. In Natural Language Inference (NLI), existing bias evaluation methods have focused on the prediction results of one specific label out of three labels, such as neutral. However, such evaluation…

2024

How You Prompt Matters! Even Task-Oriented Constraints in Instructions Affect LLM-Generated Text Detection

EMNLP 2024finding

To combat the misuse of Large Language Models (LLMs), many recent studies have presented LLM-generated-text detectors with promising performance. When users instruct LLMs to generate texts, the instruction can include different constraints depending on the user’s need. However, most recent studies d…

2024

Likelihood-based Mitigation of Evaluation Bias in Large Language Models

ACL 2024findings

Large Language Models (LLMs) are widely used to evaluate natural language generation tasks as automated metrics.However, the likelihood, a measure of LLM’s plausibility for a sentence, can vary due to superficial differences in sentences, such as word order and sentence structure.It is therefore pos…

2024

OUTFOX: LLM-Generated Essay Detection Through In-Context Learning with Adversarially Generated Examples

AAAI 2024technical

Large Language Models (LLMs) have achieved human-level fluency in text generation, making it difficult to distinguish between human-written and LLM-generated texts. This poses a growing risk of misuse of LLMs and demands the development of detectors to identify LLM-generated texts. However, existing…

2024

Two Counterexamples to Tokenization and the Noiseless Channel

COLING 2024main

In Tokenization and the Noiseless Channel (Zouhar et al., 2023), Rényi efficiency is suggested as an intrinsic mechanism for evaluating a tokenizer: for NLP tasks, the tokenizer which leads to the highest Rényi efficiency of the unigram distribution should be chosen. The Rényi efficiency is thus tre…

2023

Causal Reasoning through Two Cognition Layers for Improving Generalization in Visual Question Answering

EMNLP 2023long main

Generalization in Visual Question Answering (VQA) requires models to answer questions about images with contexts beyond the training distribution. Existing attempts primarily refine unimodal aspects, overlooking enhancements in multimodal aspects. Besides, diverse interpretations of the input lead t…

Cited by 0SourceScholar
2023

Program Chairs’ Report on Peer Review at ACL 2023

ACL 2023long

We present a summary of the efforts to improve conference peer review that were implemented at ACL’23. This includes work with the goal of improving review quality, clearer workflow and decision support for the area chairs, as well as our efforts to improve paper-reviewer matching for various kinds…

2023

Query-based Image Captioning from Multi-context 360° Images

EMNLP 2023long findings

A 360-degree image captures the entire scene without the limitations of a camera's field of view, which makes it difficult to describe all the contexts in a single caption. We propose a novel task called Query-based Image Captioning (QuIC) for 360-degree images, where a query (words or short phrases…

Cited by 1SourceScholar
2022

Debiasing Isn’t Enough! – on the Effectiveness of Debiasing MLMs and Their Social Biases in Downstream Tasks

COLING 2022main

We study the relationship between task-agnostic intrinsic and task-specific extrinsic social bias evaluation measures for MLMs, and find that there exists only a weak correlation between these two types of evaluation measures. Moreover, we find that MLMs debiased using different methods still re-lea…

2022

Gender Bias in Masked Language Models for Multiple Languages

NAACL 2022long

Masked Language Models (MLMs) pre-trained by predicting masked tokens on large corpora have been used successfully in natural language processing tasks for a variety of languages. Unfortunately, it was reported that MLMs also learn discriminative biases regarding attributes such as gender and race.…

2022

Interpretability for Language Learners Using Example-Based Grammatical Error Correction

ACL 2022long

Grammatical Error Correction (GEC) should not focus only on high accuracy of corrections but also on interpretability for language learning. However, existing neural-based GEC models mainly aim at improving accuracy, and their interpretability has not been explored.A promising approach for improving…

2022

PLOG: Table-to-Logic Pretraining for Logical Table-to-Text Generation

EMNLP 2022main

Logical table-to-text generation is a task that involves generating logically faithful sentences from tables, which requires models to derive logical-level facts from table records via logical inference. It raises a new challenge on the logical-level content planning of table-to-text models. However…

2022

Single Model Ensemble for Subword Regularized Models in Low-Resource Machine Translation

ACL 2022findings

Subword regularizations use multiple subword segmentations during training to improve the robustness of neural machine translation models. In previous subword regularizations, we use multiple segmentations in the training process but use only one segmentation in the inference. In this study, we prop…

2022

Word-level Perturbation Considering Word Length and Compositional Subwords

ACL 2022findings

We present two simple modifications for word-level perturbation: Word Replacement considering Length (WR-L) and Compositional Word Replacement (CWR).In conventional word replacement, a word in an input is replaced with a word sampled from the entire vocabulary, regardless of the length and context o…

2021

Transformer-based Lexically Constrained Headline Generation

EMNLP 2021main

This paper explores a variant of automatic headline generation methods, where a generated headline is required to include a given phrase such as a company or a product name. Previous methods using Transformer-based models generate a headline including a given phrase by providing the encoder with add…