452 research outputs found

    Learning Sentence-internal Temporal Relations

    Get PDF
    In this paper we propose a data intensive approach for inferring sentence-internal temporal relations. Temporal inference is relevant for practical NLP applications which either extract or synthesize temporal information (e.g., summarisation, question answering). Our method bypasses the need for manual coding by exploiting the presence of markers like after", which overtly signal a temporal relation. We first show that models trained on main and subordinate clauses connected with a temporal marker achieve good performance on a pseudo-disambiguation task simulating temporal inference (during testing the temporal marker is treated as unseen and the models must select the right marker from a set of possible candidates). Secondly, we assess whether the proposed approach holds promise for the semi-automatic creation of temporal annotations. Specifically, we use a model trained on noisy and approximate data (i.e., main and subordinate clauses) to predict intra-sentential relations present in TimeBank, a corpus annotated rich temporal information. Our experiments compare and contrast several probabilistic models differing in their feature space, linguistic assumptions and data requirements. We evaluate performance against gold standard corpora and also against human subjects

    Semi-Supervised Named Entity Recognition:\ud Learning to Recognize 100 Entity Types with Little Supervision\ud

    Get PDF
    Named Entity Recognition (NER) aims to extract and to classify rigid designators in text such as proper names, biological species, and temporal expressions. There has been growing interest in this field of research since the early 1990s. In this thesis, we document a trend moving away from handcrafted rules, and towards machine learning approaches. Still, recent machine learning approaches have a problem with annotated data availability, which is a serious shortcoming in building and maintaining large-scale NER systems. \ud \ud In this thesis, we present an NER system built with very little supervision. Human supervision is indeed limited to listing a few examples of each named entity (NE) type. First, we introduce a proof-of-concept semi-supervised system that can recognize four NE types. Then, we expand its capacities by improving key technologies, and we apply the system to an entire hierarchy comprised of 100 NE types. \ud \ud Our work makes the following contributions: the creation of a proof-of-concept semi-supervised NER system; the demonstration of an innovative noise filtering technique for generating NE lists; the validation of a strategy for learning disambiguation rules using automatically identified, unambiguous NEs; and finally, the development of an acronym detection algorithm, thus solving a rare but very difficult problem in alias resolution. \ud \ud We believe semi-supervised learning techniques are about to break new ground in the machine learning community. In this thesis, we show that limited supervision can build complete NER systems. On standard evaluation corpora, we report performances that compare to baseline supervised systems in the task of annotating NEs in texts. \u

    A Survey on Semantic Processing Techniques

    Full text link
    Semantic processing is a fundamental research domain in computational linguistics. In the era of powerful pre-trained language models and large language models, the advancement of research in this domain appears to be decelerating. However, the study of semantics is multi-dimensional in linguistics. The research depth and breadth of computational semantic processing can be largely improved with new technologies. In this survey, we analyzed five semantic processing tasks, e.g., word sense disambiguation, anaphora resolution, named entity recognition, concept extraction, and subjectivity detection. We study relevant theoretical research in these fields, advanced methods, and downstream applications. We connect the surveyed tasks with downstream applications because this may inspire future scholars to fuse these low-level semantic processing tasks with high-level natural language processing tasks. The review of theoretical research may also inspire new tasks and technologies in the semantic processing domain. Finally, we compare the different semantic processing techniques and summarize their technical trends, application trends, and future directions.Comment: Published at Information Fusion, Volume 101, 2024, 101988, ISSN 1566-2535. The equal contribution mark is missed in the published version due to the publication policies. Please contact Prof. Erik Cambria for detail

    Resolving pronominal anaphora using commonsense knowledge

    Get PDF
    Coreference resolution is the task of resolving all expressions in a text that refer to the same entity. Such expressions are often used in writing and speech as shortcuts to avoid repetition. The most frequent form of coreference is the anaphor. To resolve anaphora not only grammatical and syntactical strategies are required, but also semantic approaches should be taken into consideration. This dissertation presents a framework for automatically resolving pronominal anaphora by integrating recent findings from the field of linguistics with new semantic features. Commonsense knowledge is the routine knowledge people have of the everyday world. Because such knowledge is widely used it is frequently omitted from social communications such as texts. It is understandable that without this knowledge computers will have difficulty making sense of textual information. In this dissertation a new set of computational and linguistic features are used in a supervised learning approach to resolve the pronominal anaphora in document. Commonsense knowledge sources such as ConceptNet and WordNet are used and similarity measures are extracted to uncover the elaborative information embedded in the words that can help in the process of anaphora resolution. The anaphoric system is tested on 350 Wall Street Journal articles from the BBN corpus. When compared with other systems available such as BART (Versley et al. 2008) and Charniak and Elsner 2009, our system performed better and also resolved a much wider range of anaphora. We were able to achieve a 92% F-measure on the BBN corpus and an average of 85% F-measure when tested on other genres of documents such as children stories and short stories selected from the web

    Joint Discourse-aware Concept Disambiguation and Clustering

    Get PDF
    This thesis addresses the tasks of concept disambiguation and clustering. Concept disambiguation is the task of linking common nouns and proper names in a text โ€“ henceforth called mentions โ€“ to their corresponding concepts in a predefined inventory. Concept clustering is the task of clustering mentions, so that all mentions in one cluster denote the same concept. In this thesis, we investigate concept disambiguation and clustering from a discourse perspective and propose a discourse-aware approach for joint concept disambiguation and clustering in the framework of Markov logic. The contributions of this thesis are fourfold: Joint Concept Disambiguation and Clustering. In previous approaches, concept disambiguation and concept clustering have been considered as two separate tasks (Schรผtze, 1998; Ji & Grishman, 2011). We analyze the relationship between concept disambiguation and concept clustering and argue that these two tasks can mutually support each other. We propose the โ€“ to our knowledge โ€“ first joint approach for concept disambiguation and clustering. Discourse-Aware Concept Disambiguation. One of the determining factors for concept disambiguation and clustering is the context definition. Most previous approaches use the same context definition for all mentions (Milne & Witten, 2008b; Kulkarni et al., 2009; Ratinov et al., 2011, inter alia). We approach the question which context is relevant to disambiguate a mention from a discourse perspective and state that different mentions require different notions of contexts. We state that the context that is relevant to disambiguate a mention depends on its embedding into discourse. However, how a mention is embedded into discourse depends on its denoted concept. Hence, the identification of the denoted concept and the relevant concept mutually depend on each other. We propose a binwise approach with three different context definitions and model the selection of the context definition and the disambiguation jointly. Modeling Interdependencies with Markov Logic. To model the interdependencies between concept disambiguation and concept clustering as well as the interdependencies between the context definition and the disambiguation, we use Markov logic (Domingos & Lowd, 2009). Markov logic combines first order logic with probabilities and allows us to concisely formalize these interdependencies. We investigate how we can balance between linguistic appropriateness and time efficiency and propose a hybrid approach that combines joint inference with aggregation techniques. Concept Disambiguation and Clustering beyond English: Multi- and Cross-linguality. Given the vast amount of texts written in different languages, the capability to extend an approach to cope with other languages than English is essential. We thus analyze how our approach copes with other languages than English and show that our approach largely scales across languages, even without retraining. Our approach is evaluated on multiple data sets originating from different sources (e.g. news, web) and across multiple languages. As an inventory, we use Wikipedia. We compare our approach to other approaches and show that it achieves state-of-the-art results. Furthermore, we show that joint concept disambiguating and clustering as well as joint context selection and disambiguation leads to significant improvements ceteris paribus

    Knowledge Expansion of a Statistical Machine Translation System using Morphological Resources

    Get PDF
    Translation capability of a Phrase-Based Statistical Machine Translation (PBSMT) system mostly depends on parallel data and phrases that are not present in the training data are not correctly translated. This paper describes a method that efficiently expands the existing knowledge of a PBSMT system without adding more parallel data but using external morphological resources. A set of new phrase associations is added to translation and reordering models; each of them corresponds to a morphological variation of the source/target/both phrases of an existing association. New associations are generated using a string similarity score based on morphosyntactic information. We tested our approach on En-Fr and Fr-En translations and results showed improvements of the performance in terms of automatic scores (BLEU and Meteor) and reduction of out-of-vocabulary (OOV) words. We believe that our knowledge expansion framework is generic and could be used to add different types of information to the model.JRC.G.2-Global security and crisis managemen

    CLiFF Notes: Research In Natural Language Processing at the University of Pennsylvania

    Get PDF
    CLIFF is the Computational Linguists\u27 Feedback Forum. We are a group of students and faculty who gather once a week to hear a presentation and discuss work currently in progress. The \u27feedback\u27 in the group\u27s name is important: we are interested in sharing ideas, in discussing ongoing research, and in bringing together work done by the students and faculty in Computer Science and other departments. However, there are only so many presentations which we can have in a year. We felt that it would be beneficial to have a report which would have, in one place, short descriptions of the work in Natural Language Processing at the University of Pennsylvania. This report then, is a collection of abstracts from both faculty and graduate students, in Computer Science, Psychology and Linguistics. We want to stress the close ties between these groups, as one of the things that we pride ourselves on here at Penn is the communication among different departments and the inter-departmental work. Rather than try to summarize the varied work currently underway at Penn, we suggest reading the abstracts to see how the students and faculty themselves describe their work. The report illustrates the diversity of interests among the researchers here, as well as explaining the areas of common interest. In addition, since it was our intent to put together a document that would be useful both inside and outside of the university, we hope that this report will explain to everyone some of what we are about

    ํ•œ๊ตญ์–ด ์‚ฌ์ „ํ•™์Šต๋ชจ๋ธ ๊ตฌ์ถ•๊ณผ ํ™•์žฅ ์—ฐ๊ตฌ: ๊ฐ์ •๋ถ„์„์„ ์ค‘์‹ฌ์œผ๋กœ

    Get PDF
    ํ•™์œ„๋…ผ๋ฌธ (๋ฐ•์‚ฌ) -- ์„œ์šธ๋Œ€ํ•™๊ต ๋Œ€ํ•™์› : ์ธ๋ฌธ๋Œ€ํ•™ ์–ธ์–ดํ•™๊ณผ, 2021. 2. ์‹ ํšจํ•„.Recently, as interest in the Bidirectional Encoder Representations from Transformers (BERT) model has increased, many studies have also been actively conducted in Natural Language Processing based on the model. Such sentence-level contextualized embedding models are generally known to capture and model lexical, syntactic, and semantic information in sentences during training. Therefore, such models, including ELMo, GPT, and BERT, function as a universal model that can impressively perform a wide range of NLP tasks. This study proposes a monolingual BERT model trained based on Korean texts. The first released BERT model that can handle the Korean language was Google Researchโ€™s multilingual BERT (M-BERT), which was constructed with training data and a vocabulary composed of 104 languages, including Korean and English, and can handle the text of any language contained in the single model. However, despite the advantages of multilingualism, this model does not fully reflect each languageโ€™s characteristics, so that its text processing performance in each language is lower than that of a monolingual model. While mitigating those shortcomings, we built monolingual models using the training data and a vocabulary organized to better capture Korean textsโ€™ linguistic knowledge. Therefore, in this study, a model named KR-BERT was built using training data composed of Korean Wikipedia text and news articles, and was released through GitHub so that it could be used for processing Korean texts. Additionally, we trained a KR-BERT-MEDIUM model based on expanded data by adding comments and legal texts to the training data of KR-BERT. Each model used a list of tokens composed mainly of Hangul characters as its vocabulary, organized using WordPiece algorithms based on the corresponding training data. These models reported competent performances in various Korean NLP tasks such as Named Entity Recognition, Question Answering, Semantic Textual Similarity, and Sentiment Analysis. In addition, we added sentiment features to the BERT model to specialize it to better function in sentiment analysis. We constructed a sentiment-combined model including sentiment features, where the features consist of polarity and intensity values assigned to each token in the training data corresponding to that of Korean Sentiment Analysis Corpus (KOSAC). The sentiment features assigned to each token compose polarity and intensity embeddings and are infused to the basic BERT input embeddings. The sentiment-combined model is constructed by training the BERT model with these embeddings. We trained a model named KR-BERT-KOSAC that contains sentiment features while maintaining the same training data, vocabulary, and model configurations as KR-BERT and distributed it through GitHub. Then we analyzed the effects of using sentiment features in comparison to KR-BERT by observing their performance in language modeling during the training process and sentiment analysis tasks. Additionally, we determined how much each of the polarity and intensity features contributes to improving the model performance by separately organizing a model that utilizes each of the features, respectively. We obtained some increase in language modeling and sentiment analysis performances by using both the sentiment features, compared to other models with different feature composition. Here, we included the problems of binary positivity classification of movie reviews and hate speech detection on offensive comments as the sentiment analysis tasks. On the other hand, training these embedding models requires a lot of training time and hardware resources. Therefore, this study proposes a simple model fusing method that requires relatively little time. We trained a smaller-scaled sentiment-combined model consisting of a smaller number of encoder layers and attention heads and smaller hidden sizes for a few steps, combining it with an existing pre-trained BERT model. Since those pre-trained models are expected to function universally to handle various NLP problems based on good language modeling, this combination will allow two models with different advantages to interact and have better text processing capabilities. In this study, experiments on sentiment analysis problems have confirmed that combining the two models is efficient in training time and usage of hardware resources, while it can produce more accurate predictions than single models that do not include sentiment features.์ตœ๊ทผ ํŠธ๋žœ์Šคํฌ๋จธ ์–‘๋ฐฉํ–ฅ ์ธ์ฝ”๋” ํ‘œํ˜„ (Bidirectional Encoder Representations from Transformers, BERT) ๋ชจ๋ธ์— ๋Œ€ํ•œ ๊ด€์‹ฌ์ด ๋†’์•„์ง€๋ฉด์„œ ์ž์—ฐ์–ด์ฒ˜๋ฆฌ ๋ถ„์•ผ์—์„œ ์ด์— ๊ธฐ๋ฐ˜ํ•œ ์—ฐ๊ตฌ ์—ญ์‹œ ํ™œ๋ฐœํžˆ ์ด๋ฃจ์–ด์ง€๊ณ  ์žˆ๋‹ค. ์ด๋Ÿฌํ•œ ๋ฌธ์žฅ ๋‹จ์œ„์˜ ์ž„๋ฒ ๋”ฉ์„ ์œ„ํ•œ ๋ชจ๋ธ๋“ค์€ ๋ณดํ†ต ํ•™์Šต ๊ณผ์ •์—์„œ ๋ฌธ์žฅ ๋‚ด ์–ดํœ˜, ํ†ต์‚ฌ, ์˜๋ฏธ ์ •๋ณด๋ฅผ ํฌ์ฐฉํ•˜์—ฌ ๋ชจ๋ธ๋งํ•œ๋‹ค๊ณ  ์•Œ๋ ค์ ธ ์žˆ๋‹ค. ๋”ฐ๋ผ์„œ ELMo, GPT, BERT ๋“ฑ์€ ๊ทธ ์ž์ฒด๊ฐ€ ๋‹ค์–‘ํ•œ ์ž์—ฐ์–ด์ฒ˜๋ฆฌ ๋ฌธ์ œ๋ฅผ ํ•ด๊ฒฐํ•  ์ˆ˜ ์žˆ๋Š” ๋ณดํŽธ์ ์ธ ๋ชจ๋ธ๋กœ์„œ ๊ธฐ๋Šฅํ•œ๋‹ค. ๋ณธ ์—ฐ๊ตฌ๋Š” ํ•œ๊ตญ์–ด ์ž๋ฃŒ๋กœ ํ•™์Šตํ•œ ๋‹จ์ผ ์–ธ์–ด BERT ๋ชจ๋ธ์„ ์ œ์•ˆํ•œ๋‹ค. ๊ฐ€์žฅ ๋จผ์ € ๊ณต๊ฐœ๋œ ํ•œ๊ตญ์–ด๋ฅผ ๋‹ค๋ฃฐ ์ˆ˜ ์žˆ๋Š” BERT ๋ชจ๋ธ์€ Google Research์˜ multilingual BERT (M-BERT)์˜€๋‹ค. ์ด๋Š” ํ•œ๊ตญ์–ด์™€ ์˜์–ด๋ฅผ ํฌํ•จํ•˜์—ฌ 104๊ฐœ ์–ธ์–ด๋กœ ๊ตฌ์„ฑ๋œ ํ•™์Šต ๋ฐ์ดํ„ฐ์™€ ์–ดํœ˜ ๋ชฉ๋ก์„ ๊ฐ€์ง€๊ณ  ํ•™์Šตํ•œ ๋ชจ๋ธ์ด๋ฉฐ, ๋ชจ๋ธ ํ•˜๋‚˜๋กœ ํฌํ•จ๋œ ๋ชจ๋“  ์–ธ์–ด์˜ ํ…์ŠคํŠธ๋ฅผ ์ฒ˜๋ฆฌํ•  ์ˆ˜ ์žˆ๋‹ค. ๊ทธ๋Ÿฌ๋‚˜ ์ด๋Š” ๊ทธ ๋‹ค์ค‘์–ธ์–ด์„ฑ์ด ๊ฐ–๋Š” ์žฅ์ ์—๋„ ๋ถˆ๊ตฌํ•˜๊ณ , ๊ฐ ์–ธ์–ด์˜ ํŠน์„ฑ์„ ์ถฉ๋ถ„ํžˆ ๋ฐ˜์˜ํ•˜์ง€ ๋ชปํ•˜์—ฌ ๋‹จ์ผ ์–ธ์–ด ๋ชจ๋ธ๋ณด๋‹ค ๊ฐ ์–ธ์–ด์˜ ํ…์ŠคํŠธ ์ฒ˜๋ฆฌ ์„ฑ๋Šฅ์ด ๋‚ฎ๋‹ค๋Š” ๋‹จ์ ์„ ๋ณด์ธ๋‹ค. ๋ณธ ์—ฐ๊ตฌ๋Š” ๊ทธ๋Ÿฌํ•œ ๋‹จ์ ๋“ค์„ ์™„ํ™”ํ•˜๋ฉด์„œ ํ…์ŠคํŠธ์— ํฌํ•จ๋˜์–ด ์žˆ๋Š” ์–ธ์–ด ์ •๋ณด๋ฅผ ๋ณด๋‹ค ์ž˜ ํฌ์ฐฉํ•  ์ˆ˜ ์žˆ๋„๋ก ๊ตฌ์„ฑ๋œ ๋ฐ์ดํ„ฐ์™€ ์–ดํœ˜ ๋ชฉ๋ก์„ ์ด์šฉํ•˜์—ฌ ๋ชจ๋ธ์„ ๊ตฌ์ถ•ํ•˜๊ณ ์ž ํ•˜์˜€๋‹ค. ๋”ฐ๋ผ์„œ ๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” ํ•œ๊ตญ์–ด Wikipedia ํ…์ŠคํŠธ์™€ ๋‰ด์Šค ๊ธฐ์‚ฌ๋กœ ๊ตฌ์„ฑ๋œ ๋ฐ์ดํ„ฐ๋ฅผ ์ด์šฉํ•˜์—ฌ KR-BERT ๋ชจ๋ธ์„ ๊ตฌํ˜„ํ•˜๊ณ , ์ด๋ฅผ GitHub์„ ํ†ตํ•ด ๊ณต๊ฐœํ•˜์—ฌ ํ•œ๊ตญ์–ด ์ •๋ณด์ฒ˜๋ฆฌ๋ฅผ ์œ„ํ•ด ์‚ฌ์šฉ๋  ์ˆ˜ ์žˆ๋„๋ก ํ•˜์˜€๋‹ค. ๋˜ํ•œ ํ•ด๋‹น ํ•™์Šต ๋ฐ์ดํ„ฐ์— ๋Œ“๊ธ€ ๋ฐ์ดํ„ฐ์™€ ๋ฒ•์กฐ๋ฌธ๊ณผ ํŒ๊ฒฐ๋ฌธ์„ ๋ง๋ถ™์—ฌ ํ™•์žฅํ•œ ํ…์ŠคํŠธ์— ๊ธฐ๋ฐ˜ํ•ด์„œ ๋‹ค์‹œ KR-BERT-MEDIUM ๋ชจ๋ธ์„ ํ•™์Šตํ•˜์˜€๋‹ค. ์ด ๋ชจ๋ธ์€ ํ•ด๋‹น ํ•™์Šต ๋ฐ์ดํ„ฐ๋กœ๋ถ€ํ„ฐ WordPiece ์•Œ๊ณ ๋ฆฌ์ฆ˜์„ ์ด์šฉํ•ด ๊ตฌ์„ฑํ•œ ํ•œ๊ธ€ ์ค‘์‹ฌ์˜ ํ† ํฐ ๋ชฉ๋ก์„ ์‚ฌ์ „์œผ๋กœ ์ด์šฉํ•˜์˜€๋‹ค. ์ด๋“ค ๋ชจ๋ธ์€ ๊ฐœ์ฒด๋ช… ์ธ์‹, ์งˆ์˜์‘๋‹ต, ๋ฌธ์žฅ ์œ ์‚ฌ๋„ ํŒ๋‹จ, ๊ฐ์ • ๋ถ„์„ ๋“ฑ์˜ ๋‹ค์–‘ํ•œ ํ•œ๊ตญ์–ด ์ž์—ฐ์–ด์ฒ˜๋ฆฌ ๋ฌธ์ œ์— ์ ์šฉ๋˜์–ด ์šฐ์ˆ˜ํ•œ ์„ฑ๋Šฅ์„ ๋ณด๊ณ ํ–ˆ๋‹ค. ๋˜ํ•œ ๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” BERT ๋ชจ๋ธ์— ๊ฐ์ • ์ž์งˆ์„ ์ถ”๊ฐ€ํ•˜์—ฌ ๊ทธ๊ฒƒ์ด ๊ฐ์ • ๋ถ„์„์— ํŠนํ™”๋œ ๋ชจ๋ธ๋กœ์„œ ํ™•์žฅ๋œ ๊ธฐ๋Šฅ์„ ํ•˜๋„๋ก ํ•˜์˜€๋‹ค. ๊ฐ์ • ์ž์งˆ์„ ํฌํ•จํ•˜์—ฌ ๋ณ„๋„์˜ ์ž„๋ฒ ๋”ฉ ๋ชจ๋ธ์„ ํ•™์Šต์‹œ์ผฐ๋Š”๋ฐ, ์ด๋•Œ ๊ฐ์ • ์ž์งˆ์€ ๋ฌธ์žฅ ๋‚ด์˜ ๊ฐ ํ† ํฐ์— ํ•œ๊ตญ์–ด ๊ฐ์ • ๋ถ„์„ ์ฝ”ํผ์Šค (KOSAC)์— ๋Œ€์‘ํ•˜๋Š” ๊ฐ์ • ๊ทน์„ฑ(polarity)๊ณผ ๊ฐ•๋„(intensity) ๊ฐ’์„ ๋ถ€์—ฌํ•œ ๊ฒƒ์ด๋‹ค. ๊ฐ ํ† ํฐ์— ๋ถ€์—ฌ๋œ ์ž์งˆ์€ ๊ทธ ์ž์ฒด๋กœ ๊ทน์„ฑ ์ž„๋ฒ ๋”ฉ๊ณผ ๊ฐ•๋„ ์ž„๋ฒ ๋”ฉ์„ ๊ตฌ์„ฑํ•˜๊ณ , BERT๊ฐ€ ๊ธฐ๋ณธ์œผ๋กœ ํ•˜๋Š” ํ† ํฐ ์ž„๋ฒ ๋”ฉ์— ๋”ํ•ด์ง„๋‹ค. ์ด๋ ‡๊ฒŒ ๋งŒ๋“ค์–ด์ง„ ์ž„๋ฒ ๋”ฉ์„ ํ•™์Šตํ•œ ๊ฒƒ์ด ๊ฐ์ • ์ž์งˆ ๋ชจ๋ธ(sentiment-combined model)์ด ๋œ๋‹ค. KR-BERT์™€ ๊ฐ™์€ ํ•™์Šต ๋ฐ์ดํ„ฐ์™€ ๋ชจ๋ธ ๊ตฌ์„ฑ์„ ์œ ์ง€ํ•˜๋ฉด์„œ ๊ฐ์ • ์ž์งˆ์„ ๊ฒฐํ•ฉํ•œ ๋ชจ๋ธ์ธ KR-BERT-KOSAC๋ฅผ ๊ตฌํ˜„ํ•˜๊ณ , ์ด๋ฅผ GitHub์„ ํ†ตํ•ด ๋ฐฐํฌํ•˜์˜€๋‹ค. ๋˜ํ•œ ๊ทธ๋กœ๋ถ€ํ„ฐ ํ•™์Šต ๊ณผ์ • ๋‚ด ์–ธ์–ด ๋ชจ๋ธ๋ง๊ณผ ๊ฐ์ • ๋ถ„์„ ๊ณผ์ œ์—์„œ์˜ ์„ฑ๋Šฅ์„ ์–ป์€ ๋’ค KR-BERT์™€ ๋น„๊ตํ•˜์—ฌ ๊ฐ์ • ์ž์งˆ ์ถ”๊ฐ€์˜ ํšจ๊ณผ๋ฅผ ์‚ดํŽด๋ณด์•˜๋‹ค. ๋˜ํ•œ ๊ฐ์ • ์ž์งˆ ์ค‘ ๊ทน์„ฑ๊ณผ ๊ฐ•๋„ ๊ฐ’์„ ๊ฐ๊ฐ ์ ์šฉํ•œ ๋ชจ๋ธ์„ ๋ณ„๋„ ๊ตฌ์„ฑํ•˜์—ฌ ๊ฐ ์ž์งˆ์ด ๋ชจ๋ธ ์„ฑ๋Šฅ ํ–ฅ์ƒ์— ์–ผ๋งˆ๋‚˜ ๊ธฐ์—ฌํ•˜๋Š”์ง€๋„ ํ™•์ธํ•˜์˜€๋‹ค. ์ด๋ฅผ ํ†ตํ•ด ๋‘ ๊ฐ€์ง€ ๊ฐ์ • ์ž์งˆ์„ ๋ชจ๋‘ ์ถ”๊ฐ€ํ•œ ๊ฒฝ์šฐ์—, ๊ทธ๋ ‡์ง€ ์•Š์€ ๋‹ค๋ฅธ ๋ชจ๋ธ๋“ค์— ๋น„ํ•˜์—ฌ ์–ธ์–ด ๋ชจ๋ธ๋ง์ด๋‚˜ ๊ฐ์ • ๋ถ„์„ ๋ฌธ์ œ์—์„œ ์„ฑ๋Šฅ์ด ์–ด๋Š ์ •๋„ ํ–ฅ์ƒ๋˜๋Š” ๊ฒƒ์„ ๊ด€์ฐฐํ•  ์ˆ˜ ์žˆ์—ˆ๋‹ค. ์ด๋•Œ ๊ฐ์ • ๋ถ„์„ ๋ฌธ์ œ๋กœ๋Š” ์˜ํ™”ํ‰์˜ ๊ธ๋ถ€์ • ์—ฌ๋ถ€ ๋ถ„๋ฅ˜์™€ ๋Œ“๊ธ€์˜ ์•…ํ”Œ ์—ฌ๋ถ€ ๋ถ„๋ฅ˜๋ฅผ ํฌํ•จํ•˜์˜€๋‹ค. ๊ทธ๋Ÿฐ๋ฐ ์œ„์™€ ๊ฐ™์€ ์ž„๋ฒ ๋”ฉ ๋ชจ๋ธ์„ ์‚ฌ์ „ํ•™์Šตํ•˜๋Š” ๊ฒƒ์€ ๋งŽ์€ ์‹œ๊ฐ„๊ณผ ํ•˜๋“œ์›จ์–ด ๋“ฑ์˜ ์ž์›์„ ์š”๊ตฌํ•œ๋‹ค. ๋”ฐ๋ผ์„œ ๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” ๋น„๊ต์  ์ ์€ ์‹œ๊ฐ„๊ณผ ์ž์›์„ ์‚ฌ์šฉํ•˜๋Š” ๊ฐ„๋‹จํ•œ ๋ชจ๋ธ ๊ฒฐํ•ฉ ๋ฐฉ๋ฒ•์„ ์ œ์‹œํ•œ๋‹ค. ์ ์€ ์ˆ˜์˜ ์ธ์ฝ”๋” ๋ ˆ์ด์–ด, ์–ดํ…์…˜ ํ—ค๋“œ, ์ ์€ ์ž„๋ฒ ๋”ฉ ์ฐจ์› ์ˆ˜๋กœ ๊ตฌ์„ฑํ•œ ๊ฐ์ • ์ž์งˆ ๋ชจ๋ธ์„ ์ ์€ ์Šคํ… ์ˆ˜๊นŒ์ง€๋งŒ ํ•™์Šตํ•˜๊ณ , ์ด๋ฅผ ๊ธฐ์กด์— ํฐ ๊ทœ๋ชจ๋กœ ์‚ฌ์ „ํ•™์Šต๋˜์–ด ์žˆ๋Š” ์ž„๋ฒ ๋”ฉ ๋ชจ๋ธ๊ณผ ๊ฒฐํ•ฉํ•œ๋‹ค. ๊ธฐ์กด์˜ ์‚ฌ์ „ํ•™์Šต๋ชจ๋ธ์—๋Š” ์ถฉ๋ถ„ํ•œ ์–ธ์–ด ๋ชจ๋ธ๋ง์„ ํ†ตํ•ด ๋‹ค์–‘ํ•œ ์–ธ์–ด ์ฒ˜๋ฆฌ ๋ฌธ์ œ๋ฅผ ์ฒ˜๋ฆฌํ•  ์ˆ˜ ์žˆ๋Š” ๋ณดํŽธ์ ์ธ ๊ธฐ๋Šฅ์ด ๊ธฐ๋Œ€๋˜๋ฏ€๋กœ, ์ด๋Ÿฌํ•œ ๊ฒฐํ•ฉ์€ ์„œ๋กœ ๋‹ค๋ฅธ ์žฅ์ ์„ ๊ฐ–๋Š” ๋‘ ๋ชจ๋ธ์ด ์ƒํ˜ธ์ž‘์šฉํ•˜์—ฌ ๋” ์šฐ์ˆ˜ํ•œ ์ž์—ฐ์–ด์ฒ˜๋ฆฌ ๋Šฅ๋ ฅ์„ ๊ฐ–๋„๋ก ํ•  ๊ฒƒ์ด๋‹ค. ๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” ๊ฐ์ • ๋ถ„์„ ๋ฌธ์ œ๋“ค์— ๋Œ€ํ•œ ์‹คํ—˜์„ ํ†ตํ•ด ๋‘ ๊ฐ€์ง€ ๋ชจ๋ธ์˜ ๊ฒฐํ•ฉ์ด ํ•™์Šต ์‹œ๊ฐ„์— ์žˆ์–ด ํšจ์œจ์ ์ด๋ฉด์„œ๋„, ๊ฐ์ • ์ž์งˆ์„ ๋”ํ•˜์ง€ ์•Š์€ ๋ชจ๋ธ๋ณด๋‹ค ๋” ์ •ํ™•ํ•œ ์˜ˆ์ธก์„ ํ•  ์ˆ˜ ์žˆ๋‹ค๋Š” ๊ฒƒ์„ ํ™•์ธํ•˜์˜€๋‹ค.1 Introduction 1 1.1 Objectives 3 1.2 Contribution 9 1.3 Dissertation Structure 10 2 Related Work 13 2.1 Language Modeling and the Attention Mechanism 13 2.2 BERT-based Models 16 2.2.1 BERT and Variation Models 16 2.2.2 Korean-Specific BERT Models 19 2.2.3 Task-Specific BERT Models 22 2.3 Sentiment Analysis 24 2.4 Chapter Summary 30 3 BERT Architecture and Evaluations 33 3.1 Bidirectional Encoder Representations from Transformers (BERT) 33 3.1.1 Transformers and the Multi-Head Self-Attention Mechanism 34 3.1.2 Tokenization and Embeddings of BERT 39 3.1.3 Training and Fine-Tuning BERT 42 3.2 Evaluation of BERT 47 3.2.1 NLP Tasks 47 3.2.2 Metrics 50 3.3 Chapter Summary 52 4 Pre-Training of Korean BERT-based Model 55 4.1 The Need for a Korean Monolingual Model 55 4.2 Pre-Training Korean-specific BERT Model 58 4.3 Chapter Summary 70 5 Performances of Korean-Specific BERT Models 71 5.1 Task Datasets 71 5.1.1 Named Entity Recognition 71 5.1.2 Question Answering 73 5.1.3 Natural Language Inference 74 5.1.4 Semantic Textual Similarity 78 5.1.5 Sentiment Analysis 80 5.2 Experiments 81 5.2.1 Experiment Details 81 5.2.2 Task Results 83 5.3 Chapter Summary 89 6 An Extended Study to Sentiment Analysis 91 6.1 Sentiment Features 91 6.1.1 Sources of Sentiment Features 91 6.1.2 Assigning Prior Sentiment Values 94 6.2 Composition of Sentiment Embeddings 103 6.3 Training the Sentiment-Combined Model 109 6.4 Effect of Sentiment Features 113 6.5 Chapter Summary 121 7 Combining Two BERT Models 123 7.1 External Fusing Method 123 7.2 Experiments and Results 130 7.3 Chapter Summary 135 8 Conclusion 137 8.1 Summary of Contribution and Results 138 8.1.1 Construction of Korean Pre-trained BERT Models 138 8.1.2 Construction of a Sentiment-Combined Model 138 8.1.3 External Fusing of Two Pre-Trained Models to Gain Performance and Cost Advantages 139 8.2 Future Directions and Open Problems 140 8.2.1 More Training of KR-BERT-MEDIUM for Convergence of Performance 140 8.2.2 Observation of Changes Depending on the Domain of Training Data 141 8.2.3 Overlap of Sentiment Features with Linguistic Knowledge that BERT Learns 142 8.2.4 The Specific Process of Sentiment Features Helping the Language Modeling of BERT is Unknown 143 Bibliography 145 Appendices 157 A. Python Sources 157 A.1 Construction of Polarity and Intensity Embeddings 157 A.2 External Fusing of Different Pre-Trained Models 158 B. Examples of Experiment Outputs 162 C. Model Releases through GitHub 165Docto

    The Impact of Unfamiliar Proper Names on ESL Learners' Listening Comprehension

    No full text
    Vocabulary knowledge is a prerequisite to successful comprehension for native speakers and second language learners alike. Proper names, a peculiar and diverse group of lexical items, have long been the focus of discussion in general linguistics but have received practically no attention in second language vocabulary acquisition research. This study is the first attempt to assess whether proper names impact on second language learners' listening ability. First, I examine the question of how proper names can be adequately defined and discuss their semantic, structural, pragmatic and functional properties. I analyze proper names in light of the prototype theory and argue that personal, deity and pet names constitute the core of the proper name category. Names of places and enterprises occupy an intermediate position while names of events and artefacts are considered the least prototypical, i.e. peripheral members of the category. After identifying essential properties of prototypical proper names, I argue that in a spoken (as opposed to a written) text proper names cannot be considered automatically known items and place high demands on the listeners' cognitive resources. English as a second language (ESL) learners have to bring in a large amount of linguistic and encyclopaedic knowledge in order to cope with proper names in the flow of speech. I propose a 3-level model of such knowledge: recognition -> categorization -> referent properties. I then subject this model to empirical testing. The first experiment shows that among intermediate to advanced ESL learners the proper names recognition rate is around 60 percent. It is harder for ESL listeners to recognize proper names when the percentage of difficult common vocabulary in the text is high. The participants' proficiency level and the structure of a specific text were also found to affect the ability to recognize unfamiliar names. Well over a third of proper names are missed, which suggests that in real life listening, ESL learners mistake unknown common expressions for proper names and vice versa. In the second experiment, the participants' comprehension of a news story is tested under two conditions: Names Known (all proper names are familiar prior to listening) and Names Unknown (all proper names are unfamiliar). Results indicate that the presence of unfamiliar proper names hinders the intermediate to advanced proficiency learners' comprehension of a short news text as measured by immediate free recall and the ability to evaluate proper names related statements. The effect is local; it concerns comprehension of details, particularly those details that are associated with processing the proper names themselves. The Names Unknown group produced fewer details and more incorrect inferences in their recalls, scored significantly lower on the measure of proper names related comprehension, and selfreported a lower amount of comprehension. In contrast, the Names Known group produced more details and fewer incorrect inferences in their recalls, scored much higher on the measure of proper names related comprehension, and self-reported a greater degree of comprehension. The experiment also shows that participants in the Names Unknown treatment were not always able to ascertain from context what the referent of an unfamiliar proper name is, and in cases when they did, they could not extract as much information about the referent as the participants in the Names Known treatment had available. It is evidently unrealistic to expect ESL learners to determine what unfamiliar proper names refer to from context. On average, after 2-3 attempts at listening participants in the Names Unknown group were able to extract just over 40 percent of the information about the referents of unfamiliar proper names. Also participants' difficulty ratings of experimental tasks confirmed that the presence of unfamiliar proper names definitely makes the text seem harder to understand. The last experiment replicated the findings of the previous one on a larger sample. The Names Known group performed significantly better on open-ended questions and true-false-don't know statements. A substantial effect of unfamiliar proper names on the overall comprehension scores was found. Around 17 percent of the variance in the scores was accounted for by familiarity/lack of familiarity with proper names. The findings also provide some evidence in support of the claim that a name form that hints at the cognitive category its referent belongs to is less likely to adversely affect comprehension than a form that does not. Unfamiliar proper names contribute to raising the vocabulary threshold in second language listening, which should be taken into account by teachers, test-developers and other TESOL (teaching English to speakers of other languages) professionals

    Larger-first partial parsing

    Get PDF
    Larger-first partial parsing is a primarily top-down approach to partial parsing that is opposite to current easy-first, or primarily bottom-up, strategies. A rich partial tree structure is captured by an algorithm that assigns a hierarchy of structural tags to each of the input tokens in a sentence. Part-of-speech tags are first assigned to the words in a sentence by a part-of-speech tagger. A cascade of Deterministic Finite State Automata then uses this part-of-speech information to identify syntactic relations primarily in a descending order of their size. The cascade is divided into four specialized sections: (1) a Comma Network, which identifies syntactic relations associated with commas; (2) a Conjunction Network, which partially disambiguates phrasal conjunctions and llly disambiguates clausal conjunctions; (3) a Clause Network, which identifies non-comma-delimited clauses; and (4) a Phrase Network, which identifies the remaining base phrases in the sentence. Each automaton is capable of adding one or more levels of structural tags to the tokens in a sentence. The larger-first approach is compared against a well-known easy-first approach. The results indicate that this larger-first approach is capable of (1) producing a more detailed partial parse than an easy first approach; (2) providing better containment of attachment ambiguity; (3) handling overlapping syntactic relations; and (4) achieving a higher accuracy than the easy-first approach. The automata of each network were developed by an empirical analysis of several sources and are presented here in detail
    • โ€ฆ
    corecore