Thesis (Ph.D.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / The size, diversity and continued growth of the World Wide Web combine to make its understanding difficult even at the most basic levels. The focus of our work is in developing novel methods for measuring and analyzing the Web which lead to a deeper understanding of its performance. We describe a methodology and a distributed infrastructure for taking measurements in both the network and end-hosts. The first unique characteristic of the infrastructure is our ability to generate requests at our Web server which closely imitate actual users. This ability is based on detailed analysis of Web client behavior and the creation of the Scalable URL Request Generator (SURGE) tool. SURGE provides us with the flexibility to test different aspects of Web performance. We demonstrate this flexibility in an evaluation of the 1.0 and 1.1 versions of the Hyper Text Transfer Protocol. The second unique aspect of our approach is that we analyze the details of Web transactions by applying critical path analysis (CPA). CPA enables us to precisely decompose latency in Web transactions into propagation delay, network variation, server delay, client delay and packet loss delays. We present analysis of pe1formance data collected in our infrastructure. Our results show that our methods can expose surprising behavior in Web servers, and can yield considerable insight into the causes of delay variability in Web transactions. / 2031-01-01

Made available in DSpace on 2016-04-26T18:16:27Z (GMT). No. of bitstreams: 1 Dina Blanco Cadahia Conceicao.pdf: 1436662 bytes, checksum: 52ffd24be8c0e2945266af70bef3104c (MD5) Previous issue date: 2007-09-25 / The present study is a research concerning fiction text readers, either in printed or digital versions, especially on the World Wide Web. Theoretically, it includes works of recent book historians, such as Alberto Manguel, Roger Chartier and Peter Burke, so that an analysis of this media, its characteristics, readers, and the process of reading could be approached. In order to have a clearer understanding relating to changes that have been brought by the new media today, the change from the text to the hypertext and the advent of the 'cyber literature', I also explore the studies of authors such as Pierre Lévy, Lucia Santaella, and Janet Murray, among others. The corpus considered is composed of some classical literary compositions in digital format such as 'Os Lusíadas' by Luiz Vaz de Camões, and 'Iracema' by José de Alencar, which are compared to printed versions. Having started with the hypothesis that young fiction readers do not read books, I believe that such hypothesis was confirmed; however, it has also been noticed that, even with the Internet, they do not read as much and, a lot of times, the Internet per se is of great usefulness for printed books / O presente estudo constitui-se de uma pesquisa teórica, de índole comparativa, em torno dos leitores de textos de ficção impressos e textos de ficção nos meios digitais, principalmente na rede de computadores. Baseio-me nas obras e teorizações dos recentes historiadores do livro, a exemplo de Alberto Manguel, Roger Chartier e Peter Burke, para investigar a história desta mídia, com sua figuração própria do autor, do leitor e da leitura. Para uma maior compreensão das transformações que estão sendo trazidas hoje pelas novas mídias, notadamente a passagem do texto ao hipertexto e o advento da assim chamada "ciberliteratura", exploro os trabalhos de autores como Pierre Lévy, Lucia Santaella e Janet Murray, entre outros. O corpus da pesquisa compõe-se de pesquisa dos leitores das ficções hipertextuais que, segundo a investigação realizada, estão suplantando a cultura do livro. Entram aí algumas obras da literatura clássica, a exemplo de Os Lusíadas, de Luiz Vaz de Camões e Iracema, de José de Alencar, cuja formatação digital comparamos com as clássicas formatações impressas. Tendo partido da hipótese de que os atuais jovens leitores de ficção passam ao largo do livro, acredito ter podido mostrar que tal hipótese se confirma, embora tenha ficado evidenciado também que, mesmo na rede de computadores, eles não lêem tanto e, muitas vezes, a rede de computadores sirva de novo o texto impresso

Some of the theory of nonnegative matrices is first presented. The Perron-Frobenius theorem is highlighted. Some of the important linear algebraic methods of information retrieval are surveyed. Latent Semantic Indexing (LSI), which uses the singular value de-composition is discussed. The Hyper-Text Induced Topic Search (HITS) algorithm is next considered; here the power method for finding dominant eigenvectors is employed. Through the use of a theorem by Sinkohrn and Knopp, a modified HITS method is developed. Lastly, the PageRank algorithm is discussed. Numerical examples and MATLAB programs are also provided.

Made available in DSpace on 2014-07-29T15:00:26Z (GMT). No. of bitstreams: 1 dissertacao welson.pdf: 912896 bytes, checksum: 72883793b6905efaaca4549e6406ac90 (MD5) Previous issue date: 2009-03-26 / This work is the result of a qualitative research on participative nature that arouse from the study of facts and analysis of bachelor in mathematics II (DID2), during the first semester of 2008 in the college of mathematics and statistics at Goiás Federal University (UFG). The main purpose of this research was to verify the range on which the virtual classes could either or neither contribute to the learning process. The study was shaped according to 50% of presence classes and 50% of non presence ones. Virtual learning was used for non presence activities (AVA) Moodle. In the context of the research, the researcher was a copartner in the working up and effective accomplishment of pedagogical activities and virtual ones (AVA), as well as a researcher in exercise in the presence and non presence activities, developed by his/her professor. Because of the pedagogical range that the subject presented itself, thematic cuttings were essential for data analysis. Communicational perspectives were researched then, hyper textual information about the developed subject and the above-mentioned (AVA). With the analysis categories of every perspective above-mentioned, interchanges of speech were developed in forum and chats when, they were contrasted it was found the construction of an interactive communication and expressive textual dialogue as the priority perspective signalized. Simultaneously, the dissertation also contributed to sections, whose debates gave a subsidy to themes, not totally clarified by the approach pertaining to a not present education (EaD). The themes approached passed by possible differences between interaction and interactivities, and also about the possibility to create communicational spaces, which developed themselves. It also holds conceptions about emblematical themes, technologies of information and communication (TIC) and (AVA). The legal base about the EaD and some contributions examined in the development of the subject that lay the foundation and stimulate virtual practices. In this context the research created new thoughts about pedagogical virtual practices, mainly to involve the researched subject, a non conventional practice in similar research in the field of Mathematics. This practice approaches a subject in the field of education not for the specific Mathematics subject.Perspective and hypertextual communication in the light of technology in education through the use of Forums and Chat the Didactics of Mathematics / Este trabalho é o resultado de uma pesquisa qualitativa de cunho participativo que surgiu da observação e da análise da disciplina Didática da Matemática II (DID2), ministrada no primeiro semestre de 2008, no Instituto de Matemática e Estatística da Universidade Federal de Goiás (UFG). O objetivo principal da pesquisa é verificar em que medida a utilização de aulas desenvolvidas virtualmente pode contribuir ou não para a aprendizagem. A disciplina configurou-se em 50% de atividades presenciais e 50% em atividades não presenciais. Nas atividades não presenciais, utilizou-se o Ambiente Virtual de Aprendizagem (AVA) Moodle. No contexto da pesquisa o pesquisador foi um sujeito co-participante na elaboração e execução das atividades pedagógicas e virtuais no AVA e pesquisador das práticas pedagógicas presenciais e não presenciais desenvolvidas por seu orientador e, também, professor da disciplina. Pela abrangência pedagógica que a disciplina proporcionou fez-se necessário realizar recortes temáticos para análise dos dados. Foram, então, pesquisadas as perspectivas comunicacional e hipertextual à luz da disciplina desenvolvida e do referido AVA. Elaboradas as categorias de análise de cada perspectiva supracitada, foram selecionadas interlocuções desenvolvidas nos Fóruns e Chats realizados que, ao serem contrastadas, verificaram-se as construções de um espaço comunicacional interativo e de diálogos textuais significativos como as expectativas primeiras sinalizavam. Simultaneamente, a dissertação contribui também com seções cujas discussões subsidiaram temas não muito esclarecidos na abordagem sobre Educação a Distância (EaD). Os temas abordados perpassam pela ambígua interpretação entre interação e interatividade e sobre a possibilidade de se criar espaços comunicacionais que as desenvolvam. Tece-se, também, concepções sobre os temas emblemáticos Tecnologias de Informação e Comunicação (TIC) e AVA, a fundamentação legal sobre a EaD e certas contribuições observadas no desenvolvimento da disciplina que alicerçam e estimulam práticas virtuais. Nesse contexto, a pesquisa engendra novas reflexões sobre práticas pedagógicas virtuais, principalmente, por envolver, a disciplina pesquisada, uma prática não convencional em pesquisas semelhantes na área da matemática. Essa prática aborda uma disciplina da área de educação e não uma disciplina específica da Matemática.