{"created":"2021-03-01T06:01:14.529325+00:00","id":8930,"links":{},"metadata":{"_buckets":{"deposit":"1794e653-1f80-4034-8849-cdd7b2c1d09c"},"_deposit":{"id":"8930","owners":[],"pid":{"revision_id":0,"type":"depid","value":"8930"},"status":"published"},"_oai":{"id":"oai:kitami-it.repo.nii.ac.jp:00008930","sets":["2:6"]},"author_link":["90469"],"item_7_biblio_info_6":{"attribute_name":"書誌情報","attribute_value_mlt":[{"bibliographicIssueDates":{"bibliographicIssueDate":"2020-09","bibliographicIssueDateType":"Issued"}}]},"item_7_date_granted_63":{"attribute_name":"学位授与年月日","attribute_value_mlt":[{"subitem_dategranted":"2020-09-07"}]},"item_7_degree_grantor_61":{"attribute_name":"学位授与機関","attribute_value_mlt":[{"subitem_degreegrantor":[{"subitem_degreegrantor_language":"ja","subitem_degreegrantor_name":"北見工業大学"}]}]},"item_7_degree_name_60":{"attribute_name":"学位名","attribute_value_mlt":[{"subitem_degreename":"博士（工学）","subitem_degreename_language":"ja"}]},"item_7_description_4":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":"Technologies being developed within the field of Natural Language Processing (NLP) have an important role to play in the urgent tasks of documenting, analyzing and revitalizing endangered languages. At the same time, the rapid development and the spread of language-related technologies observed in recent decades may result in creating a technological gap between smaller languages and majority languages – which in turn will threaten the survival of the former group – if linguistic minorities are not provided with equal access to said technologies. Among such languages is Ainu, a critically endangered language isolate native to northern parts of the Japanese archipelago. In this dissertation, I present the results of my research devoted to the development of Natural Language Processing technologies for the Ainu language.\n I begin with presenting the background of this research. In particular, I provide an overview of previous research in the field of Natural Language Processing for under-resourced and endangered languages. I then describe the characteristics and current situation of the Ainu language, and review some of the related research on the Ainu language, including the few existing studies in the field of Natural Language Processing. I also describe the major challenges facing Ainu language research and revitalization efforts.\nAfter that, I report the results of a survey conducted on a group of Ainu language learners, scholars, and other people interested in the Ainu language, with the aim of evaluating their experiences and needs concerning language-related technologies. Based on the findings from the questionnaire, I outline future research goals.\n A major obstacle for the application of advanced language processing technologies to minority languages, including Ainu, is the lack of high-volume digital linguistic resources, such as text and speech corpora and in particular, annotated corpora. One of the main contributions of the presented research is the compilation of a large-scale corpus of Ainu. It covers a wide range of documents in a consistent structure, allowing for the application of corpus-driven approaches to NLP, such as statistical language models and representation learning techniques.\n The above-mentioned corpus is then utilized in the development of Natural Language Processing tools for Ainu, namely word segmentation models and part-of-speech taggers. For the first task, I propose a novel algorithm: MiNgMatch Segmenter. I argue that the problem of identifying word boundaries can be reduced to finding the shortest sequence of lexical n-grams matching the input text, thus reducing its computational cost and increasing efficiency of the process. I perform a series of experiments comparing the algorithm with systems utilizing state-of-the-art statistical language modelling techniques, as well as a neural model performing word segmentation as character sequence labelling. The experimental results demonstrate strong performance of the proposed approach, comparable with the other best-performing models. Next, I apply a state-of-the-art generator of sequential taggers – SVMTool – and a tagger based on Artificial Neural Networks, equipped with word representations inferred from the corpus, in the task of automatic part-of-speech annotation. Evaluation results reveal that they perform better than the dictionary-based system proposed in previous research (POST-AL), especially when applied to out-of-domain data.\n Furthermore, I describe a preliminary Ainu language conversational program for the Pepper robot, which serves as a proof of concept of how robots could support Ainu language education. The proposed robot can hold simple conversations, teach new words and play interactive games using the Ainu language. In a group of Ainu language experts and experienced learners whom I asked for feedback (in the form of a survey study), the majority supported the idea of developing an Ainu-speaking robot and using it in language teaching.\nAdvances in cross-lingual learning indicate that the problems facing Natural Language\n Processing for low-resource languages can be, to a certain extent, alleviated by transferring knowledge from resource-rich languages. Unsurprisingly, however, such techniques tend to yield the best results for closely related languages, whereas the Ainu language is a language isolate, with no known cognates. Nevertheless, given the similarity of phonological systems and some grammatical constructions between Ainu and Japanese, it may still be beneficial to use the existing Japanese resources as a starting point in the development of language processing technologies for Ainu. In this thesis, I describe two preliminary experiments in cross-lingual knowledge transfer from Japanese to Ainu: firstly, I propose a method for generating useful word representations by using an Ainu-Japanese parallel corpus with morpho-syntactic annotations on the Japanese side. When applied to the problem of part-of-speech tagging of Ainu text, the proposed method contributes positively to the performance of a neural tagger. Secondly, I investigate the performance of Japanese models for Speech Synthesis and Speech Recognition in generating and detecting speech in the Ainu language. I perform human evaluation of the synthesized speech in terms of intelligibility and pronunciation, as well as automatic evaluation of Speech Recognition. Experiment results suggest that cross-lingual transfer from Japanese has a potential to facilitate the development of speech technologies for Ainu, especially in the case of Speech Recognition.","subitem_description_language":"en","subitem_description_type":"Abstract"},{"subitem_description":"「自然言語処理」（NLP）研究分野は，消滅の危機に瀕している少数言語の記録保存や分析，再活性化といった喫緊の課題解決において重要な役割を担うと期待されている． ここ数十年において言語関連技術は急速に発展・普及しているが，少数言語話者に対してもそれらの技術を活用する機会が与えられなければ，多数言語と少数言語との間に技術的ギャップが生じ，後者の危機がさらに深刻化する恐れがある． これらの言語には，日本の現地語の一つであり危機言語となっているアイヌ語がある． 本論文では，アイヌ語のための自然言語処理技術開発に関する研究結果について報告する．\n　まず，本研究の背景を紹介する． 具体的には，自然言語処理の分野における言語資源の少ない言語および消滅危機にある言語を対象とした先行研究を簡潔に紹介する． 次に，アイヌ語の特徴と現状を説明し，自然言語処理分野における数少ないアイヌ語に関する研究を紹介するとともに，アイヌ語の研究および復興の取り組みが直面している主たる課題について説明する．\n　次に，アイヌ語のための言語処理技術の潜在的なユーザーの特徴や具体的なニーズを知るため，アイヌ語に関わる諸活動に携わっている人々（研究者，学習者，講師など）を対象に実施されたアンケート調査の結果を報告する． そして，アンケートの結果をもとに，今後の研究課題について論述する．\n　最先端の自然言語処理技術を有効活用するためには，統一された形式を持つ大量のテキストからなるデータベース，すなわち「電子化コーパス」が不可欠である． アイヌ語についてはオンライン辞書や資料集が多少存在するものの，規模の大きな電子化コーパスは今まで存在しなかった． 本研究の主要な貢献の一つはこの問題に対処することである．筆者は，統計的言語モデルや分散表現学習など，大規模なコーパスを必要とする自然言語処理手法の応用を可能にする，186万文字からなるアイヌ語の電子化コーパスを設計し構築したことである．\n　続いて，構築したコーパスを単語分割モデルおよび品詞タガーといったアイヌ語のための自然言語処理技術の開発に応用した． 前者においては，MiNgMatch Segmenterという，入力文と一致する最短の単語n-gram列を探索する高速の単語分割アルゴリズムを提案，実装した． そして，提案手法の有効性を検証するために，最先端の統計的言語モデルを利用した単語分割器および文字単位で処理を行う「文字タグ付け法」に基づくニューラルネットワークベースの単語分割器を用いて比較実験を実施した結果，提案手法が十分に有効であることが確認できた． 次に，Support Vector Machines手法を応用した最先端の品詞解析ツール（SVMTool）と，コーパスから学習した分散表現を用いたニューラルネットワークベースの品詞タガーをアイヌ語の品詞解析に応用した． 上記タガーの有効性を検証するために，先行研究で提案された辞書ベースの品詞タガーであるPOST-ALと比較する検証実験を行った結果，提案手法の性能が大幅に上回っていることが確認された．\nさらに，アイヌ語教育の場面においてAIやロボットの活用可能性を論証するすることを目的として，アイヌ語の自動会話プログラムをロボットに搭載して活用するための予備実験を実施した． ロボットは，アイヌ語で簡単な会話をすることの他に，新しい単語を教えたり，アイヌ語を用いたインタラクティブゲームを実行することもできる． アイヌ語を話すロボットを開発し言語教育に応用するアイデアに関して，アイヌ語の専門家や学習者を対象にアンケート調査を実施した結果，回答者のほとんどが賛成であることが分かった．\n　最後に，日本語からアイヌ語への知識転移の効果について報告する． 近年における「マルチリンガル学習」の進化が示しているように，言語資源の少ない言語の自然言語処理が直面する問題は，資源が豊富な言語から知識を転移することによってある程度軽減できる． ただし，当然のことながら，そのような手法は近縁言語に対して最良の結果をもたらす傾向がある一方，アイヌ語のようないわゆる「孤立言語」には効果が小さいと考えられる． しかし，アイヌ語と日本語との音韻体系やいくつかの文法構造の類似性を考慮すると，日本語データを用いたマルチリンガル学習がアイヌ語の言語処理技術を開発する上で有効であると期待できる． 筆者は，日本語からアイヌ語への知識転移の効果を検証するために2つの実験を実施した． まず，アイヌ語-日本語対訳コーパスと日本語形態素解析器を使用し，有効な単語分散表現（単語ベクトル）を計算する方法を構築した． 構築した手法は，アイヌ語テキストの品詞解析の問題においてニューラルの品詞タガーの精度の向上に貢献することが確認された． 次に，日本語音声合成および音声認識モデルのアイヌ語に応用した際のパフォーマンスを検証した． 合成されたアイヌ語音声の理解度および発音について，人間による評価と音声認識の自動評価を行った． その結果，日本語からの言語知識の転移がアイヌ語音声技術の開発を促進する可能性があることが示唆された．\n　以上より，本論文で報告した，絶滅危機言語であるアイヌ語を対象とした一連の自然言語処理技術の開発研究の成果が，アイヌ語の保存復興に十分貢献するものと結論できる．","subitem_description_language":"ja","subitem_description_type":"Abstract"}]},"item_7_dissertation_number_64":{"attribute_name":"学位授与番号","attribute_value_mlt":[{"subitem_dissertationnumber":"10106甲第184号"}]},"item_7_identifier_registration":{"attribute_name":"ID登録","attribute_value_mlt":[{"subitem_identifier_reg_text":"10.19000/00008893","subitem_identifier_reg_type":"JaLC"}]},"item_7_select_15":{"attribute_name":"著者版フラグ","attribute_value_mlt":[{"subitem_select_item":"ETD"}]},"item_7_text_66":{"attribute_name":"研究科・専攻名","attribute_value_mlt":[{"subitem_text_language":"ja","subitem_text_value":"生産基盤工学専攻"}]},"item_access_right":{"attribute_name":"アクセス権","attribute_value_mlt":[{"subitem_access_right":"open access","subitem_access_right_uri":"http://purl.org/coar/access_right/c_abf2"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"KAROL PIOTR, NOWAKOWSKI","creatorNameLang":"en"},{"creatorName":"カロル　ピオトル, ノヴァコフスキ","creatorNameLang":"ja-Kana"}],"nameIdentifiers":[{"nameIdentifier":"90469","nameIdentifierScheme":"WEKO"}]}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2020-10-06"}],"displaytype":"detail","filename":"Ko184_KAROL_PIOTR_NOWAKOWSKI.pdf","filesize":[{"value":"2.4 MB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"甲184_KAROL PIOTR NOWAKOWSKI","objectType":"fulltext","url":"https://kitami-it.repo.nii.ac.jp/record/8930/files/Ko184_KAROL_PIOTR_NOWAKOWSKI.pdf"},"version_id":"c156e525-b239-4db9-85e5-990e20118d74"}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"eng"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"doctoral thesis","resourceuri":"http://purl.org/coar/resource_type/c_db06"}]},"item_title":"Development of a Digital Corpus and Core Language Technologies for the Ainu Language","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"Development of a Digital Corpus and Core Language Technologies for the Ainu Language","subitem_title_language":"en"},{"subitem_title":"アイヌ語の電子コーパス及び基盤言語技術の開発における研究","subitem_title_language":"ja"}]},"item_type_id":"7","owner":"1","path":["6"],"pubdate":{"attribute_name":"PubDate","attribute_value":"2020-10-06"},"publish_date":"2020-10-06","publish_status":"0","recid":"8930","relation_version_is_last":true,"title":["Development of a Digital Corpus and Core Language Technologies for the Ainu Language"],"weko_creator_id":"1","weko_shared_id":-1},"updated":"2022-12-13T02:24:00.805002+00:00"}