Extraction of Keyphrases from Text: Evaluation of Four Algorithms

This report presents an empirical evaluation of four algorithms for automatically extracting keywords and keyphrases from documents. The four algorithms are compared using five different collections of documents. For each document, we have a target set of keyphrases, which were generated by hand. The target keyphrases were generated for human readers; they were not tailored for any of the four keyphrase extraction algorithms. Each of the algorithms was evaluated by the degree to which the algorithm’s keyphrases matched the manually generated keyphrases. The four algorithms were (1) the AutoSummarize feature in Microsoft’s Word 97, (2) an algorithm based on Eric Brill’s part-of-speech tagger, (3) the Summarize feature in Verity’s Search 97, and (4) NRC’s Extractor algorithm. For all five document collections, NRC’s Extractor yields the best match with the manually generated keyphrases

Learning to Extract Keyphrases from Text

Many academic journals ask their authors to provide a list of about five to fifteen key words, to appear on the first page of each article. Since these key words are often phrases of two or more words, we prefer to call them keyphrases. There is a surprisingly wide variety of tasks for which keyphrases are useful, as we discuss in this paper. Recent commercial software, such as Microsoft?s Word 97 and Verity?s Search 97, includes algorithms that automatically extract keyphrases from documents. In this paper, we approach the problem of automatically extracting keyphrases from text as a supervised learning task. We treat a document as a set of phrases, which the learning algorithm must learn to classify as positive or negative examples of keyphrases. Our first set of experiments applies the C4.5 decision tree induction algorithm to this learning task. The second set of experiments applies the GenEx algorithm to the task. We developed the GenEx algorithm specifically for this task. The third set of experiments examines the performance of GenEx on the task of metadata generation, relative to the performance of Microsoft?s Word 97. The fourth and final set of experiments investigates the performance of GenEx on the task of highlighting, relative to Verity?s Search 97. The experimental results support the claim that a specialized learning algorithm (GenEx) can generate better keyphrases than a general-purpose learning algorithm (C4.5) and the non-learning algorithms that are used in commercial software (Word 97 and Search 97)

Construindo grafos de conhecimento utilizando documentos textuais para análise de literatura científica

Orientador: Julio Cesar dos ReisDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de ComputaçãoResumo: O número de publicações científicas que pesquisadores tem que ler vem aumento nos últimos anos. Consequentemente, dentre várias opções, é difícil para eles identificarem documentos relevantes relacionados aos seus estudos. Ademais, para entender como um campo científico é organizado, e para estudar o seu estado da arte, pesquisadores geralmente se baseiam em artigos de revisão de uma área. Estes artigos podem estar indisponíveis ou desatualizados dependendo do tema estudado. Usualmente, pesquisadores têm que realizar esta árdua tarefa de pesquisa fundamental manualmente. Pesquisas recentes vêm desenvolvendo mecanismos para auxiliar outros pesquisadores a entender como campos científicos são estruturados. Entretanto, estes mecanismos são focados exclusivamente em recomendar artigos relevantes para os pesquisadores ou os auxiliar em entender como um ramo da ciência é organizado ao nível de publicação. Desta forma, estes métodos limitam o entendimento sobre o ramo estudado, não permitindo que interessados estudem os conceitos e relações abstratas que compõe um ramo da ciência e as suas subáreas. Esta dissertação de mestrado propõe um framework para estruturar, analisar, e rastrear a evolução de um campo científico no nível dos seus conceitos. Ela primeiramente estrutura o campo científico como um grafo-de-conhecimento utilizando os seus conceitos como vértices. A seguir, ela automaticamente identifica as principais subáreas do campo estudado, extrai as suas frases-chave, e estuda as suas relações. Nosso framework representa o campo científico em diferentes períodos do tempo. Esta dissertação compara estas representações, e identifica como as subáreas do campo estudado evoluiram no decorrer dos anos. Avaliamos cada etapa do nosso framework representando e analisando dados científicos provenientes de diferentes áreas de conhecimento em casos de uso. Nossas descobertas indicam o sucesso em detectar resultados similares em diferentes casos de uso, indicando que nossa abordagem é aplicável à diferentes domínios da ciência. Esta pesquisa também contribui com uma aplicação com interface web para auxiliar pesquisadores a utilizarem nosso framework de forma gráfica. Ao utilizar nossa aplicação, pesquisadores podem ter uma análise geral de como um campo científico é estruturado e como ele evoluiAbstract: The amount of publications a researcher must absorb has been increasing over the last years. Consequently, among so many options, it is hard for them to identify interesting documents to read related to their studies. Researchers usually search for review articles to understand how a scientific field is organized and to study its state of the art. This option can be unavailable or outdated depending on the studied area. Usually, they have to do such laborious task of background research manually. Recent researches have developed mechanisms to assist researchers in understanding the structure of scientific fields. However, those mechanisms focus on recommending relevant articles to researchers or supporting them in understanding how a scientific field is organized considering documents that belong to it. These methods limit the field understanding, not allowing researchers to study the underlying concepts and relations that compose a scientific field and its sub-areas. This Ms.c. thesis proposes a framework to structure, analyze, and track the evolution of a scientific field at a concept level. Given a set of textual documents as research papers, it first structures a scientific field as a knowledge graph using its detected concepts as vertices. Then, it automatically identifies the field's main sub-areas, extracts their keyphrases, and studies their relations. Our framework enables to represent the scientific field in distinct time-periods. It allows to compare its representations and identify how the field's areas changed over time. We evaluate each step of our framework representing and analyzing scientific data from distinct fields of knowledge in case studies. Our findings indicate the success in detecting the sub-areas based on the generated graph from natural language documents. We observe similar outcomes in the different case studies by indicating our approach applicable to distinct domains. This research also contributes with a web-based software tool that allows researchers to use the proposed framework graphically. By using our application, researchers can have an overview analysis of how a scientific field is structured and how it evolvedMestradoCiência da ComputaçãoMestre em Ciência da Computação2013/08293-7 ; 2017/02325-5FAPESPCAPE

BibRank: Automatic Keyphrase Extraction Platform Using~Metadata

Automatic Keyphrase Extraction involves identifying essential phrases in a document. These keyphrases are crucial in various tasks such as document classification, clustering, recommendation, indexing, searching, summarization, and text simplification. This paper introduces a platform that integrates keyphrase datasets and facilitates the evaluation of keyphrase extraction algorithms. The platform includes BibRank, an automatic keyphrase extraction algorithm that leverages a rich dataset obtained by parsing bibliographic data in BibTeX format. BibRank combines innovative weighting techniques with positional, statistical, and word co-occurrence information to extract keyphrases from documents. The platform proves valuable for researchers and developers seeking to enhance their keyphrase extraction algorithms and advance the field of natural language processing.Comment: 12 pages , 4 figures, 8 table