The emergence of the Internet has made the global information communications much easier than before. Users can navigate the desired information over the Internet by means of search engines. Even though search engine can help users search specified topic in a primary way, users usually cannot gain the overall idea of what the entire navigated results mean. In addition, information over the Internet keeps changing. Users cannot even keep track of the changes, let alone to comprehend the meanings of such changes. Consequently, this research proposes a two-stage incremental approach to figuring out the concept structure that represents the main concepts of the search results in the first stage, and keeping track of the concept changes with time based on spreading activation theory to assist users in the second stage. Experiments are conducted to examine the feasibility of our proposed approach. The first experiment is to evaluate the results from the first stage. It shows that the performance on recall and precision is quite satisfactory based on human experts¡¦ results. The second experiment is to examine the changing results from the entire proposed approach. It shows that high degree of agreement with our results is achieved from domain experts. Both experiments justify the feasibility of our proposed approach in real applications. That is, applying our proposed approach, users can easily focus on the topic they are interested in and learn its trend with great support. Keywords: Internet, Concepts Extraction, Concept Change Detection, Spreading Activation Theory.

To manage the information flood in the Internet, we usually navigate specific information using the provided search engines. Search engines are convenient but with limited functions. For example, it is impractical and impossible to browse through the entire collected information for us to gain an overall picture about what the navigated information stands for. To do so, we need an appropriate approach to automatically extracting concepts from the navigated information to assist users to easily and quickly gain the primary understanding toward a topic that interests users. In this research, we propose an approach to extracting concepts from the navigated web information and detecting the concept changes over time. It basically includes two stages. In the first stage, information is decomposed into paragraphs and they are clustered with key terms identified through the aid of latent semantic indexing method. Concepts are represented in the form of paragraph summary and associated key terms, which allows the user to easily comprehend what they describe. The second stage is to adaptively modify the concept structure to detect concept changes. With new information added, the concepts could be merging, splitting, or even emerging with time. Three experiments are conducted in this research to verify the proposed approach. Results of the first and second experiments show both high recall and high precision that matches the predefined concept categories. The last one is an illustrated real case application on the tsunami event. It shows that we can easily grasp different concepts of the tsunami reports and realize their changes by using our approach. The feasibility of employing our approach is thus justified.

Information acquisition over the Internet has become popular recently. Users, however, have difficulty in understanding the overall concept resulting from the searched information about a specific topic of their interests in the Internet. Moreover, such pieces of information keep changing over time. Therefore, in this thesis, an approach is proposed to help users further realize the searched results of their interested topic, and detect implications of the information changes over time. The first part of this approach is to gather information of a user-specified topic and analyze the overall meaning and the relations represented by those pieces of information. In this manner, users can gain the general concept of what the search results indicate. Here the keyword extraction approach, called RCBKE, is proposed to identify keywords with their relationships. Evaluations are performed and the results show that RCBKE can discover representative keywords. The second part is to track and investigate the information change of the topic in a certain time period. As a result, users can easily recognize the change patterns of the specified topic. An example to illustrate our approach is shown accordingly. The feasibility of our proposed approach is then justified.

Submitted by JOSIANE SANTOS DE OLIVEIRA (josianeso) on 2018-04-18T16:33:53Z No. of bitstreams: 1 Adriano Cagol_.pdf: 619508 bytes, checksum: 490415002d6a9bb9ff9bb7f968e23b21 (MD5) / Made available in DSpace on 2018-04-18T16:33:53Z (GMT). No. of bitstreams: 1 Adriano Cagol_.pdf: 619508 bytes, checksum: 490415002d6a9bb9ff9bb7f968e23b21 (MD5) Previous issue date: 2017-04-27 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / As demonstrações financeiras apresentam o desempenho financeiro das empresas e são uma importante ferramenta para análise da situação patrimonial e financeira, bem como para tomada de decisões de investidores, credores, fornecedores, clientes, entre outros. Nelas constam as notas explicativas que descrevem em detalhes as práticas e políticas de comunicação dos métodos de contabilidade da empresa, além de informações adicionais. Dependendo dos objetivos, não é possível uma correta análise da situação de uma entidade através das demonstrações financeiras, sem a interpretação e análise das notas explicativas que as acompanham. Porém, apesar da importância, a análise automática das notas explicativas das demonstrações financeiras ainda é um obstáculo. Em vista desta deficiência, este trabalho propõe um modelo que aplica técnicas de mineração textual para efetivar a extração de conceitos e a sumarização das notas explicativas, relativas à seção de principais práticas contábeis adotadas pela empresa, no sentido de identificar e estruturar os principais métodos de apuração de contas contábeis e a geração de resumos. Um algoritmo de extração de conceitos e seis algoritmos de sumarização foram aplicados sobre as notas explicativas das demonstrações financeiras de empresas da Comissão de Valores Mobiliários do Brasil. O trabalho mostra que a extração de conceitos gera resultados promissores para identificação do método de apuração da conta contábil, visto que apresenta acurácia de 100% na nota explicativa do estoque e do imobilizado e acurácia de 96,97% na nota explicativa do reconhecimento da receita. Além disso, avalia os algoritmos de sumarização com a medida ROUGE, apontando os mais promissores, com destaque para o LexRank, que no geral conseguiu as melhores avaliações. / Financial statements present the financial performance of companies and are an important tool for analyzing the financial and equity situation, as well as for making decisions of investors, creditors, suppliers, customers, among others. These are listed explanatory notes that describe in detail how practices and policies of accounting methods of the company. Depending on the objectives, a correct analysis of the situation of a company on the financial statements is not possible without an interpretation and analysis of the footnotes. However, despite the importance, an automatic analysis of the footnotes to the financial statements is still an obstacle. In view of this deficiency, this work proposes a model that applies text mining techniques without the sense of identifying the main methods of calculating the accounting accounts, the reports in the footnotes, with concept extraction, as well as generating a summary that contemplates the main idea of these, through summarization. A concept extraction algorithm and six summarization algorithms are applied in financial statements of companies of Brazilian Securities and Exchange Commission. The work shows that concept extraction generates promising results for the identification of the method of calculating the accounting account, since it presents a 100% accuracy in the footnote of inventory and property, plant and equipment, and accuracy of 96.97% in the footnote on revenue recognition. In addition, it evaluates the algorithms for summarization with the ROUGE measure, pointing out the most promising ones, especially LexRank, which in general obtained the best evaluations.