Papers by Naoaki Okazaki
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| Challenge: | In natural language, we often omit some words that are easily understandable from the context. |
| Approach: | They propose to use a dataset to evaluate whether translation models can resolve zero pronoun problems in Japanese to English translations. |
| Outcome: | The proposed model can resolve the zero pronoun problem in Japanese to English translations. |
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| Challenge: | Several studies have addressed explainable recommendations that produce natural language sentences . however, this task cannot explain detailed evidences for each hotel . |
| Approach: | They propose to decompose the process into two subtasks: Evidence Identification and Evidence Explanation. |
| Outcome: | The proposed model can explain evidences in recommending hotels given vague requests . it can find evidence sentences with respect to various vague requests and generate recommendation sentences . |
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| Challenge: | Existing work on news-image captioning requires a joint understanding of image and text. |
| Approach: | They propose a Transformer model that integrates text and image modalities and attends to textual features from visual features in generating a caption. |
| Outcome: | The proposed model outperforms the state-of-the-art model and improves the quality of news-image captions. |
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| Challenge: | Existing studies present tokens, examples, and hints for corrections, but do not directly explain the reasons in natural language. |
| Approach: | They propose a method called controlled generation with Prompt Insertion that uses Large Language Models to explain the reasons for corrections in natural language. |
| Outcome: | The proposed method can explain the reasons for corrections in natural language by guiding the LLMs to generate explanations for all correction points. |
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| Challenge: | Existing subword regularizations use multiple segmentations during training but only use one segmentation in inference. |
| Approach: | They propose an inference strategy that uses multiple subword segmentations to solve this discrepancy in the training process and inference. |
| Outcome: | The proposed strategy reduces the cost of training and improves the performance of models trained with subword regularization in low-resource machine translation tasks. |
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| Challenge: | a pre-trained language model with low OOV can improve performance for transfer learning . a vocabulary surrogate can provide performance boosts with no additional computation cost . |
| Approach: | They propose multiple methods to mitigate OOV during downstream task fine-tuning . they demonstrate that vocabulary surrogates can provide performance boosts with no additional computation cost . |
| Outcome: | The proposed methods improve performance with the same parameter count when combined with fine-tuning. |
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| Challenge: | Existing methods to generate video descriptions fail to mention objects and actions in videos . |
| Approach: | They propose an LSTM-based sequence-to-sequence model with semantic attention mechanism for video description generation that includes external fine-grained visual information. |
| Outcome: | The proposed model can selectively focus on external fine-grained visual information and have a better quality of video descriptions. |
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| Challenge: | Existing models often refer to the same data record multiple times. |
| Approach: | They propose a data-to-text generation model with two modules, one for tracking and the other for text generation. |
| Outcome: | The proposed model outperforms existing models even without writer information in all evaluation metrics and contributes to content planning and surface realization. |
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| Challenge: | Recent studies have tried to evaluate and mitigate social biases accurately using limited prompts. |
| Approach: | They investigate the sensitivity of Large Language Models when changing prompt variations . they found that LLM rankings fluctuate across prompts for both task performance and social bias . |
| Outcome: | The results show that LLM rankings fluctuate when changing prompt variations . |
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| Challenge: | ACL'23 makes its peer review report public and an official part of the conference proceedings. |
| Approach: | They present an analysis of the factors affecting peer review and identify the most problematic issues that the authors complained about. |
| Outcome: | The authors identified the most problematic issues and provided suggestions for the future chairs. |
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| Challenge: | Social media provide platforms to express, discuss, and shape opinions about events and issues in the real world. |
| Approach: | They propose to use factorization machines to model user preferences toward topics from social media data to predict whether a given text/user is in favor (agree), against (disagreer), or neutral toward a target topic. |
| Outcome: | The proposed method can predict stances of silent users based on their stance toward other topics and the social media posts of the user. |
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| Challenge: | Recent studies suggest that neural language models learn and store a large amount of facts and commonsense knowledge from training data. |
| Approach: | They propose a benchmark task that evaluates the amount of relational knowledge stored in pre-trained language models. |
| Outcome: | The proposed evaluations show that the selection of confidence functions is more robust to simple guesses than the accuracy-based evaluation. |
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| Challenge: | Document-level Relation Extraction (DocRE) is the task of extracting all semantic relationships from a document. |
| Approach: | They propose to transfer an English document to Japanese to promote DocRE in other languages. |
| Outcome: | The proposed model reduces the human edit steps by 50% compared with the previous approach. |
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| Challenge: | Existing methods to optimize tokenizations for downstream tasks are not suitable for traditional NLP. |
| Approach: | They propose a method to explore a tokenization appropriate for a downstream task . they train a model to assign a high probability to such appropriate tokenization based on the downstream task loss . |
| Outcome: | The proposed method improves sentiment analysis and textual entailment tasks . it is also integrated into state-of-the-art contextualized embeddings and reports a positive effect . |
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| Challenge: | Existing methods for automatic evaluation of grammatical error correction require multiple reference sentences or manual scores. |
| Approach: | They propose an Impact-based Metric for GEC using PARAllel data, IMPARA . IMPRA computes correction impacts computed by parallel data comprising pairs of grammatical/ungrammatically-spaced sentences. |
| Outcome: | The proposed method can perform evaluations that fit different domains and correction styles. |
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| Challenge: | Large Language Models (LLMs) are trained on large-scale web data, which makes it difficult to grasp the contribution of each text. |
| Approach: | They propose a membership-inference attack method that uses only the input text to detect leaks. |
| Outcome: | The proposed method performs on par with existing likelihood-based methods even without likelihoods. |
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| Challenge: | 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. |
| Approach: | They propose to use English attribute word lists to evaluate bias in eight languages without manually annotating data. |
| Outcome: | The proposed model significantly correlates with the existing English datasets for gender bias. |
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| Challenge: | Large Language Models (LLMs) are widely used to evaluate natural language generation tasks as automated metrics. |
| Approach: | They propose to use LLMs to evaluate sentences with higher likelihoods and lower likelihoods to mitigate the likelihood bias. |
| Outcome: | The proposed method overrates sentences with higher likelihoods while underrating sentences with lower likelihoods. |
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| Challenge: | Large-scale pretraining and task-specific fine-tuning are now the standard methodology for many tasks in computer vision and natural language processing. |
| Approach: | They propose to combine two types of vision and language BERTs to create a theoretical framework that can be unified under different theoretical frameworks. |
| Outcome: | The proposed models can be classified into single-stream or dual-stream encoders and are unified under a single theoretical framework. |
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| Challenge: | Logical table-to-text generation requires models to derive logical-level facts from table records via logical inference. |
| Approach: | They propose a pretrained logical form generator framework to improve generation fidelity . they use a dataset to test the logical inference accuracy of the framework . |
| Outcome: | The proposed framework outperforms baselines on LOGICNLG and CONTLOG on two benchmarks. |
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| Challenge: | Formality style transfer (FST) is a task that involves paraphrasing an informal sentence into a formal one without altering its meaning. |
| Approach: | They propose a semi-supervised framework to better utilize source-side unlabeled sentences based on consistency training. |
| Outcome: | The proposed framework can achieve state-of-the-art results even with less than 40% of the parallel data. |
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| Challenge: | lack of large-scale open Japanese image-text pairs poses a significant barrier to the development of vision-language models. |
| Approach: | They construct large-scale Japanese image-text pairs using machine translation and pre-trained CLIP models on a Japanese dataset. |
| Outcome: | The results show that pre-trained models achieve competitive average scores on Japanese culture tasks compared to models of similar size. |
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| Challenge: | Existing NLP systems cannot properly handle North Korean inputs, despite limited data . Several NLP researchers have been working on the Korean language . |
| Approach: | They propose to manually create evaluation data for automatic alignment and machine translation, and investigate automatic alignment methods suitable for North Korean. |
| Outcome: | The proposed model trained by North Korean bilingual data significantly boosts translation accuracy compared to existing South Korean models in zero-shot settings. |
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| Challenge: | IR models with a pretrained language model outperform lexical approaches like BM25 for vocabulary mismatch. |
| Approach: | They propose an unsupervised domain adaptation method by filling vocabulary gaps by expanding queries and documents through an MLM. |
| Outcome: | The proposed method outperforms the current state-of-the-art domain adaptation method on datasets with a large vocabulary gap from a source domain. |
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| Challenge: | Existing studies use pseudo cross-lingual abstractive summarization data to train neural encoder-decoders. |
| Approach: | They propose a multi-task learning framework for cross-lingual abstractive summarization that attaches a special token to the beginning of the input sentence to indicate the target task. |
| Outcome: | The proposed model achieves better performance than the model trained with only pseudo cross-lingual abstractive summarization data. |
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| Challenge: | Existing image captioning datasets follow salient images with limited camera field of view, ignoring minor details. |
| Approach: | They propose a task where a query specifies the context to describe in 360-degree images and construct a dataset for the task that contains 3,940 360- degree images and 18,459 pairs of queries and captions annotated manually. |
| Outcome: | The proposed task is more challenging than the conventional image captioning task, which describes salient objects in images. |
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| Challenge: | Character-level language modeling has been shown to perform well on highly agglutinative or morphologically rich languages while using only a small fraction of the parameters required by (sub)word models. |
| Approach: | They propose a “three-hot” embedding and decoding scheme that exploits the decomposability of Korean characters to model at the syllable level but using only jamo-level representations. |
| Outcome: | The proposed model reduces the embedding parameters by 99.6% and does not lose translation quality compared to the baseline model. |
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| Challenge: | Mixture of Experts (MoE) models use homogeneous experts with diverse capacities, resulting in a lack of expert specialization and parameter utilization. |
| Approach: | They propose a framework where experts differ in size and possess diverse capacities . they propose HMoE to encourage frequent activation of smaller experts . |
| Outcome: | The proposed framework outperforms homogeneous homogenous MoE models on evaluation benchmarks and achieves lower loss rate with fewer activated parameters. |
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| Challenge: | Existing methods for knowledge-based Word Sense Disambiguation (WSD) use only lexical knowledge to adapt contextualized embeddings. |
| Approach: | They propose a semantic specialization where contextualized embeddings are adapted to the WSD task using only lexical knowledge. |
| Outcome: | The proposed method outperforms previous studies that adapt contextualized embeddings while controlling deviations from the original embeddables. |
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| Challenge: | Existing attempts to generalize VQA focus on unimodal aspects, overlooking enhancements in multimodal aspects. |
| Approach: | They propose to decompose the responsibility of each stage into distinct experts and a cognition-enabled component (CC) they prioritize answer predictions governed by pathways involving both CCs while disregarding answers produced by either CC. |
| Outcome: | The proposed model improves multimodal predictions by emphasizing causal reasoning factors. |
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| Challenge: | Existing approaches to analyze text contain rewrites and inconsistency between text and quads. |
| Approach: | They propose a new approach to analyze aspect terms, opinion terms, sentiment polarity in text . they augment quads and train a quads-to-text model to generate corresponding texts . |
| Outcome: | The proposed method outperforms existing methods and achieves state-of-the-art performance on two datasets. |
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| Challenge: | Recent studies have presented LLM-generated-text detectors with promising performance, but they do not cover such diverse instruction patterns when creating datasets for LLM detection. |
| Approach: | They propose to use task-oriented constraints that would naturally be included in an instruction and are not related to detection-evasion to create detectors with large variances in detection performance. |
| Outcome: | The proposed detectors have a large variance in detection performance on student essay writing with task-oriented constraints, and the standard deviation is significantly larger than that on texts generated by the constraint with such a constraint. |
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| Challenge: | Recent studies on mechanistic interpretability revealed that long-context factuality is closely related to a set of attention heads, retrieval heads. |
| Approach: | They propose a method that generates training signals by contrasting normal model outputs with those from an ablated variant. |
| Outcome: | The proposed method achieves significant improvements on LLMs with a sparse retrieval score distribution. |
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| Challenge: | Existing interpretable detectors are not aligned with the human decision-making process and fail to offer evidence that users easily understand. |
| Approach: | They propose an interpretable detection approach that checks whether a text is human-written or LLM-generated by checking whether it shares more similar spans with human-generated texts. |
| Outcome: | ExaGPT outperforms interpretable detectors by +37.0 points at a false positive rate of 1%. |
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| Challenge: | Existing automatic headline generation methods cannot include a given phrase in the generated headline. |
| Approach: | They propose a Transformer-based method that guarantees to include a given phrase in a generated headline. |
| Outcome: | The proposed method achieves ROUGE scores comparable to previous methods with Japanese news corpus. |
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| Challenge: | Currently, most neural machine translation models rely on pairs of parallel sentences, assuming syntactic information is automatically learned by an attention mechanism. |
| Approach: | They propose a parameter-free, dependency-aware self-attention mechanism that integrates syntactic knowledge into a Transformer model and propose 'a parameter free approach' they also propose - a novel mechanism that improves translation quality for long sentences and in low-resource scenarios. |
| Outcome: | The proposed approach improves translation quality on English-German and English-Turkish translation tasks and in low-resource scenarios. |
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| Challenge: | Existing studies on abstractive summarization report ROUGE scores, but are concerned about the truthfulness of generated summaries. |
| Approach: | They propose to remove untruthful instances from supervision data to improve headline generation . they build a binary classifier that predicts an entailment relation between an article and its headline . |
| Outcome: | The proposed model improves on two popular datasets. |
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| Challenge: | Existing measures for social bias evaluation are inadequate for MLMs to accurately evaluate the social biases in their systems. |
| Approach: | They propose task-agnostic intrinsic and task-specific extrinsic social bias evaluation measures for MLMs that use different methods to re-learn social biases during fine-tuning on downstream tasks. |
| Outcome: | The findings highlight the limitations of existing MLM bias evaluation measures and raise concerns on the deployment of MLMs in downstream applications using those measures. |
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| Challenge: | Neural encoder-decoder models have been successful in natural language generation tasks, but they must be limited to a specified length for abstractive summarization. |
| Approach: | They propose a sinusoidal positional extension to preserve the length constraint so that a neural encoder-decoder model can generate a text of any length even if the target length is unseen in training data. |
| Outcome: | The proposed method can generate a text of any length even if the target length is unseen in training data and improves ROUGE scores. |
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| Challenge: | Word replacement considering length and compositional word replacement are effective word-level perturbations. |
| Approach: | They propose two simple modifications for word-level perturbation: Word Replacement considering Length and Compositional Word Replacement. |
| Outcome: | The proposed methods improve word-level perturbation and classification performance. |
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| Challenge: | Nevertheless, Rényi efficiency is not perfect and the metric is difficult to evaluate because training multiple tokenizers can be prohibitively expensive and takes days or weeks. |
| Approach: | They propose to use Rényi efficiency as an intrinsic mechanism to evaluate a tokenizer for NLP tasks without the expensive step of training multiple models with different tokenizers. |
| Outcome: | The proposed metric is better correlated to downstream model performance than a percentile frequency metric. |
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| Challenge: | Recent studies indicated that neural methods are governed by the scaling law for the amount of training data. |
| Approach: | They propose a low-cost strategy to augment training data for abstractive summarization tasks by extracting summarized text and paraphrasing it. |
| Outcome: | The proposed strategy outperforms back-translation and self-training and is more cost-efficient when training data is small. |
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| Challenge: | Existing methods to develop meta-embeddings from source embeddings contain unfair gender-related biases, and how these influence the meta-bedding has not been studied yet. |
| Approach: | They propose to use multiple debiasing methods on a single source embedding to create a gender-based meta-embedding. |
| Outcome: | The proposed method amplifies gender biases compared to input source embeddings. |
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| Challenge: | Existing neural-based GEC models mainly aim at improving accuracy, but their interpretability has not been explored. |
| Approach: | They propose an example-based method that generates corrections using retrieved examples. |
| Outcome: | The proposed method improves interpretability and supports language learners. |
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| Challenge: | Existing systems that make predictions and ask questions are unable to have a mutual exchange of opinions. |
| Approach: | They propose to use a dataset and computational framework to allow systems to have beneficial discussions with humans, improving the accuracy by 25 points on a natural language inference task. |
| Outcome: | The proposed system improves accuracy by 25 points on a natural language inference task. |
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| Challenge: | Existing methods to evaluate gender bias in PLMs focus on one label out of three labels, such as neutral. |
| Approach: | They propose a bias evaluation method for PLMs that considers all the three labels of NLI task and then defines a measure based on the corresponding label output. |
| Outcome: | The proposed method can distinguish biased, incorrect inferences from non-biased incorrect infertility better than baseline, resulting in a more accurate bias evaluation. |
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| Challenge: | Large Language Models (LLMs) have demonstrated remarkable performance in various tasks and gained significant attention. |
| Approach: | They propose to predict edit spans for local sequence transduction tasks by predicting edit span with a position of the source text and corrected tokens. |
| Outcome: | The proposed method reduces the length of the target sequence and the computational cost for inference by as small as 21%. |
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| Challenge: | Existing methods to evaluate gender biases in pre-trained language models have been limited by the cost and difficulties of recruiting human annotators. |
| Approach: | They propose a method to compare intrinsic gender bias evaluation measures without relying on human annotated examples. |
| Outcome: | The proposed method compares gender-based gender bias evaluation measures without human annotators without human input. |
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| Challenge: | a vocabulary size problem is unsolved in multilingual pre-training tasks. |
| Approach: | They propose two algorithms that increase the elasticity of budget for building the vocabulary in Byte-Pair Encoding inspired tokenizers, and reduce the cost of supporting Korean in a multilingual model. |
| Outcome: | The proposed method reduces the cost of supporting Korean in a multilingual model. |
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| Challenge: | Korean uses spaces at larger-than-word boundaries, unlike other East-Asian languages. |
| Approach: | They propose to use Korean morphological analyzers to provide a sequence of morpheme-level tokens, losing information in the tokenization process. |
| Outcome: | The proposed scheme improves existing tagging scheme and makes it friendlier to generative tasks. |
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| Challenge: | Subword regularization reduces the dependency on exact tokenizations, augments training corpus, and exposes model to unique contexts during training. |
| Approach: | They propose an algorithm to uniformly sample subword tokenizations to replace stochastic variants that are biased towards a small set of tokenization per word. |
| Outcome: | The proposed algorithm reduces the dependency on exact tokenizations and augments the training corpus. |
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| Challenge: | Document-level relation extraction (DocRE) is a task of identifying relations between entities in a document. evidence retrieval (ER) in DocRE faces two major issues: high memory consumption and limited availability of annotations. |
| Approach: | They propose a memory-efficient approach that uses evidence as the supervisory signal . they propose er self-training to learn ER from automatically-generated evidence . |
| Outcome: | The proposed method exhibits state-of-the-art performance on the DocRED benchmark . it uses evidence as the supervisory signal and self-trains on massive data without annotations . |
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| Challenge: | Existing studies have reported that an appropriate tokenization depends on each downstream task. |
| Approach: | They propose a method to find an appropriate tokenization to a downstream task by optimizing a tokenizer and a model. |
| Outcome: | The proposed method improves on text classification and machine translation tasks. |
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| Challenge: | Current state-of-the-art MT systems are based on neural networks, but it is unclear whether all translation directions are equally easy (or hard) to model for NMT. |
| Approach: | They propose an asymmetric information-theoretic metric of machine translation difficulty that exploits the probabilistic nature of most neural machine translation models. |
| Outcome: | The proposed metric allows us to better evaluate the difficulty of translating text into the target language while controlling for the difficulty independent of the translation task. |