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Generating Relation Descriptions with Large Language Model for Link Prediction
http://doi.org/10.5626/JOK.2024.51.10.908
The Knowledge Graph is a network consisting of entities and the relations between them. It is used for various natural language processing tasks. One specific task related to the Knowledge Graph is Knowledge Graph Completion, which involves reasoning with known facts in the graph and automatically inferring missing links. In order to tackle this task, studies have been conducted on both link prediction and relation prediction. Recently, there has been significant interest in a dual-encoder architecture that utilizes textual information. However, the dataset for link prediction only provides descriptions for entities, not for relations. As a result, the model heavily relies on descriptions for entities. To address this issue, we utilized a large language model called GPT-3.5-turbo to generate relation descriptions. This allows the baseline model to be trained with more comprehensive relation information. Moreover, the relation descriptions generated by our proposed method are expected to improve the performance of other language model-based link prediction models. The evaluation results for link prediction demonstrate that our proposed method outperforms the baseline model on various datasets, including Korean ConceptNet, WN18RR, FB15k-237, and YAGO3-10. Specifically, we observed improvements of 0.34%p, 0.11%p, 0.12%p, and 0.41%p in terms of Mean Reciprocal Rank (MRR), respecitvely.
Multi-task Learning Based Re-ranker for External Knowledge Retrieval in Document-grounded Dialogue Systems
http://doi.org/10.5626/JOK.2023.50.7.606
Document-grounded dialogue systems retrieve external passages related to the dialogue and use them to generate an appropriate response to the user"s utterance. However, the retriever based on the dual-encoder architecture records low performance in finding relevant passages, and the re-ranker to complement the retriever is not sufficiently optimized. In this paper, to solve these problems and perform effective external passage retrieval, we propose a re-ranker based on multi-task learning. The proposed model is a cross-encoder structure that simultaneously learns contrastive learning-based ranking, Masked Language Model (MLM), and Posterior Differential Regularization (PDR) in the fine-tuning stage, enhancing language understanding ability and robustness of the model through auxiliary tasks of MLM and PDR. Evaluation results on the Multidoc2dial dataset show that the proposed model outperforms the baseline model in Recall@1, Recall@5, and Recall@10.
Solving Korean Math Word Problems Using the Graph and Tree Structure
Kwang Ho Bae, Sang Yeop Yeo, Yu Chul Jung
http://doi.org/10.5626/JOK.2022.49.11.972
In previous studies, there have been various efforts to solve math word problems in the English sentence system. In many studies, improved performance was achieved by introducing structures such as trees and graphs, beyond the Sequence-to-Sequence approaches. However, in the study of solving math problems in Korean sentence systems, there are no model cases, using structures such as trees or graphs. Thus, in this paper, we examine the possibility of solving math problems in Korean sentence systems for models using the tree structure, graph structure, and Korean pre-training language models together. Our experimental results showed that accuracy improved by approximately 20%, compared to the model of the Seq2seq structure, by introducing the graph and tree structure. Additionally, the use of the Korean pre-training language model showed an accuracy improvement of 4.66%-5.96%.
Entity Graph Based Dialogue State Tracking Model with Data Collection and Augmentation for Spoken Conversation
http://doi.org/10.5626/JOK.2022.49.10.891
As a part of a task-oriented dialogue system, dialogue state tracking is a task for understanding the dialogue and extracting user’s need in a slot-value form. Recently, Dialogue System Track Challenge (DSTC) 10 Track 2 initiated a challenge to measure the robustness of a dialogue state tracking model in a spoken conversation setting. The released evaluation dataset has three characteristics: new multiple value scenario, three-times more entities, and utterances from automatic speech recognition module. In this paper, to ensure the model’s robust performance, we introduce an extraction-based dialogue state tracking model with entity graph. We also propose to use data collection and template-based data augmentation method. Evaluation results prove that our proposed method improves the performance of the extraction-based dialogue state tracking model by 1.7% of JGA and 0.57% of slot accuracy compared to baseline model.
Structuralized External Knowledge and Multi-task Learning for Knowledge Selection
http://doi.org/10.5626/JOK.2022.49.10.884
Typically, task-oriented dialog systems use well-structured knowledge, such as databases, to generate the most appropriate responses to users" questions. However, to generate more appropriate and fluent responses, external knowledge, which is unstructured text data such as web data or FAQs, is necessary. In this paper, we propose a novel multi-task learning method with a pre-trained language model and a graph neural network. The proposed method makes the system select the external knowledge effectively by not only understanding linguistic information but also grasping the structural information latent in external knowledge which is converted into structured data, graphs, using a dependency parser. Experimental results show that our proposed method obtains higher performance than the traditional bi-encoder or cross-encoder methods that use pre-trained language models.
Knowledge Graph Completion using Hyper-class Information and Pre-trained Language Model
http://doi.org/10.5626/JOK.2021.48.11.1228
Link prediction is a task that aims to predict missing links in knowledge graphs. Recently, several link prediction models have been proposed to complete the knowledge graphs and have achieved meaningful results. However, the previous models used only the triples" internal information in the training data, which may lead to an overfitting problem. To address this problem, we propose Hyper-class Information and Pre-trained Language Model (HIP) that performs hyper-class prediction and link prediction through a multi-task learning. HIP learns not only contextual relationship of triples but also abstractive meanings of entities. As a result, it learns general information of the entities and forces the entities connected to the same hyper-class to have similar embeddings. Experimental results show significant improvement in Hits@10 and Mean Rank (MR) compared to KG-BERT and MTL-KGC.
Evaluating of Korean Machine Reading Comprehension Generalization Performance via Cross-, Blind and Open-Domain QA Dataset Assessment
http://doi.org/10.5626/JOK.2021.48.3.275
Machine reading comprehension (MRC) entails identification of the correct answer in a paragraph when a natural language question and paragraph are provided. Recently, fine-tuning based on a pre-trained language model yields the best performance. In this study, we evaluated the ability of machine-reading comprehension method to generalize question and paragraph pairs, rather than similar training sets. Towards this end, the cross-evaluation between datasets and blind evaluation was performed. The results showed a correlation between generalization performance and datasets such as answer length and overlap ratio between question and paragraph. As a result of blind evaluation, the evaluation dataset with the long answer and low lexical overlap between the questions and paragraphs resulted in less than 80% performance. Finally, the generalized performance of the MRC model under the open domain QA environment was evaluated, and the performance of the MRC using the searched paragraph was found to be degraded. According to the MRC task characteristics, the difficulty and differences in generalization performance depend on the relationship between the question and the answer, suggesting the need for analysis of different evaluation sets.
Korean Dependency Parsing using Token-Level Contextual Representation in Pre-trained Language Model
http://doi.org/10.5626/JOK.2021.48.1.27
Dependency parsing is a problem of disambiguating sentence structure by recognizing dependencies and labels between words in sentences. In contrast to previous studies that have applied additional RNNs to the pre-trained language model, this paper proposes a dependency parsing method that uses fine-tuning alone to maximize the self-attention mechanism of the pre-trained language model, and also proposes a technique for using relative distance parameters and SEP tokens. In the results of evaluating the Sejong parsing corpus of TTA standard guidelines, the KorBERT_base model showed 95.73% UAS and 93.39% LAS while the KorBERT_large model showed 96.31% UAS and 94.17% LAS. This represents an improvement of about 3% compared to the results of previous studies that did not use the pre-trained language model. Next, the results of the word-morpheme mixed transformation corpus of the previous study showed that the KorBERT_base model was 94.19% UAS and that the KorBERT_large model was 94.76% UAS.
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