Browsing by Author "Yuan, Chenhan"

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    Collection Management of Electronic Theses and Dissertations (CME) CS5604 Fall 2019
    Kaushal, Kulendra Kumar; Kulkarni, Rutwik; Sumant, Aarohi; Wang, Chaoran; Yuan, Chenhan; Yuan, Liling (Virginia Tech, 2019-12-23)
    The class ``CS 5604: Information Storage and Retrieval'' in the fall of 2019 is divided into six teams to enhance the usability of the corpus of electronic theses and dissertations maintained by Virginia Tech University Libraries. The ETD corpus consists of 14,055 doctoral dissertations and 19,246 masters theses from Virginia Tech University Libraries’ VTechWorks system. Our study explored document collection and processing, application of Elasticsearch to the collection to facilitate searching, testing a custom front-end, Kibana, integration, implementation, text analytics, and machine learning. The result of our work would help future researchers study the natural language processed data using deep learning technologies, address the challenges of extracting information from ETDs, etc. The Collection Management of Electronic Theses and Dissertations (CME) team was responsible for processing all PDF files from the ETD corpus and extracting well-formatted text files from them. We also used advanced deep learning and other tools like GROBID to process metadata, obtain text documents, and generate chapter-wise data. In this project, the CME team completed the following steps: comparing different parsers; doing document segmentation; preprocessing the data; and specifying, extracting, and preparing metadata and auxiliary information for indexing. We finally developed a system that automates all the above-mentioned tasks. The system also validates the output metadata, thereby ensuring the correctness of the data that flows through the entire system developed by the class. This system, in turn, helps to ingest new documents into Elasticsearch.
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    N-ary Cross-sentence Relation Extraction: From Supervised to Unsupervised Learning
    Yuan, Chenhan (Virginia Tech, 2021-05-19)
    Relation extraction is the problem of extracting relations between entities described in the text. Relations identify a common "fact" described by distinct entities. Conventional relation extraction approaches focus on supervised binary intra-sentence relations, where the assumption is relations only exist between two entities within the same sentence. These approaches have two key limitations. First, binary intra-sentence relation extraction methods can not extract a relation in a fact that is described by more than two entities. Second, these methods cannot extract relations that span more than one sentence, which commonly occurs as the number of entities increases. Third, these methods assume a supervised setting and are therefore not able to extract relations in the absence of sufficient labeled data for training. This work aims to overcome these limitations by developing n-ary cross-sentence relation extraction methods for both supervised and unsupervised settings. Our work has three main goals and contributions: (1) two unsupervised binary intra-sentence relation extraction methods, (2) a supervised n-ary cross-sentence relation extraction method, and (3) an unsupervised n-ary cross-sentence relation extraction method. To achieve these goals, our work includes the following contributions: (1) an automatic labeling method for n-ary cross-sentence data, which is essential for model training, (2) a reinforcement learning-based sentence distribution estimator to minimize the impact of noise on model training, (3) a generative clustering-based technique for intra-sentence unsupervised relation extraction, (4) a variational autoencoder-based technique for unsupervised n-ary cross-sentence relation extraction, and (5) a sentence group selector that identifies groups of sentences that form relations.