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Search Results: 1 - 10 of 21028 matches for " Cristina;Urbizagástegui Alvarado "
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La ley de Zipf y el punto de transición de Goffman en la indización automática
Urbizagástegui Alvarado, Rubén;Restrepo Arango, Cristina;
Investigación bibliotecológica , 2011,
Abstract: to identify keywords with high semantic value in the thematic content of a scientific paper the goffman's transition point is applied. a total of 1,644 different words were identified in the text. these words were arranged in descending order of frequency to explore four possibilities. in the first examination both, functional words and words with high semantic value were taken into account. in the second examination, the functional words were removed; and in the third examination both functional words as well as words with high semantic content, were lemmatized. in the fourth examination only functional word were eliminated. the result shows the identification of specific keywords.
Modelando la distribución del número de co-autores por artículo
Urbizagástegui Alvarado, Rubén;Restrepo Arango, Cristina;
Investigación bibliotecológica , 2011,
Abstract: in the literature produced about lotka's law from 1922 to june 2010, the geometric distribution, truncated poisson distribution, poisson lognormal distribution, and the generalized inverse gaussian poisson distribution are studied to statistically model the number the authors who collaborate in the publication of an article. it was found that the poisson lognormal distribution more closely estimated the total value of documents, followed by the truncated poisson model, the geometric distribution, and finally the generalized inverse gaussian poisson distribution.
La productividad de los autores en la ciencia de la información colombiana
Restrepo Arango, Cristina;Urbizagástegui Alvarado, Rubén;
Ciência da Informa??o , 2010, DOI: 10.1590/S0100-19652010000300001
Abstract: the scientific productivity of the authors who have published papers in four journals of library and information science from colombia since 1978 to 2009, was analyzed. a total of 555 authors were found; 422 (76%) of them published a single article and 78 (24%) published 2 or more articles. eleven authors were considered as the most productive with 21 and 7 articles respectively. the data was analyzed with the generalized inverse power, inverse generalized gauss poisson, and poisson lognormal models by the maximum likelihood method. the statistical chi-square and k-s tests showed that the three models fit the observed data.
Las publicaciones sobre el péndulo: un análisis comparativo Publications on the Pendulum: a comparative analysis
Cristina Restrepo Arango,Rubén Urbizagástegui Alvarado
Investigación bibliotecológica , 2012,
Abstract: Este trabajo re-evalúa la productividad de los autores sobre la literatura del péndulo publicada desde 1629 a 1885. Replica los datos del trabajo de Moreno-Cabo & Solaz-Portolés (2008). Se aplican los modelos del cuadrado inverso, poder inverso generalizado, Poisson compuesto y Poisson lognormal por el método de la máxima probabilidad. Los resultados obtenidos muestran que el modelo Poisson lognormal y el modelo del poder inverso generalizado son los que estiman los autores observados más coherentemente. El test estadístico Kolgomorov-Smirnov confirma el ajuste de los modelos del poder inverso generalizado, Poisson lognormal y Poisson compuesto y rechaza el ajuste del modelo del cuadrado inverso. This study examines the production of the literature on the pendulum published from 1629 to 1885. The findings of Moreno-Cabo & Solaz-Portolés (2008) are replicated. The data are analyzed through the following statistical methods: inverse square, generalized inverse power, and compound Poisson and Poisson log-normal by maximum likelihood models. The results show that the Poisson lognormal and generalized inverse power are those that estimate the observed authors most consistently. The statistical test Kolgomorov-Smirnov confirms the fit of the generalized inverse power, Poisson lognormal, and compound Poisson, while rejecting the inverse square model.
La ley de Zipf y el punto de transición de Goffman en la indización automática Zipf's law and goffman's transition point in the automatic indexing
Rubén Urbizagástegui Alvarado,Cristina Restrepo Arango
Investigación bibliotecológica , 2011,
Abstract: Con el fin de identificar las palabras con un alto valor semántico en el contenido temático de un artículo científico se explora el punto de transición de Goffman. Esta técnica se aplicó a 1,644 palabras diferentes identificadas en el texto. Las palabras fueron ordenadas en tablas de frecuencias en orden descendente para explorar cuatro posibilidades. En la primera exploración se tuvieron en cuenta tanto las palabras funcionales como las palabras con un alto valor semántico; en la segunda exploración se eliminaron las palabras funcionales; en la tercera exploración se lematizaron tanto las palabras funcionales como las palabras con un alto contenido semántico, en la cuarta exploración se eliminaros las palabras funcionales. Los resultados obtenidos en las cuatro exploraciones coinciden en la identificación de las palabras clave. To identify keywords with high semantic value in the thematic content of a scientific paper the Goffman's transition Point is applied. A total of 1,644 different words were identified in the text. These words were arranged in descending order of frequency to explore four possibilities. In the first examination both, functional words and words with high semantic value were taken into account. In the second examination, the functional words were removed; and in the third examination both functional words as well as words with high semantic content, were lemmatized. In the fourth examination only functional word were eliminated. The result shows the identification of specific keywords.
Modelando la distribución del número de co-autores por artículo Modeling the distribution of co-authorships by paper
Rubén Urbizagástegui Alvarado,Cristina Restrepo Arango
Investigación bibliotecológica , 2011,
Abstract: Este artículo explora la modelación del número de autores que colaboran en la publicación de un artículo. Con ese fin se analizaron la distribución geométrica, la distribución Poisson truncada, la distribución Poisson lognormal y la distribución Gauss Poisson inversa generalizada en la literatura producida sobre la Ley de Lotka desde 1922 hasta junio de 2010. Se encontró que la distribución Poisson lognormal estimó más cercanamente el valor total de los documentos observados seguida del modelo Poisson truncado, la distribución geométrica y finalmente el modelo Gauss Poisson inversa generalizada. In the literature produced about Lotka's law from 1922 to June 2010, the geometric distribution, truncated Poisson distribution, Poisson lognormal distribution, and the generalized inverse Gaussian Poisson distribution are studied to statistically model the number the authors who collaborate in the publication of an article. It was found that the Poisson lognormal distribution more closely estimated the total value of documents, followed by the truncated Poisson model, the geometric distribution, and finally the generalized inverse Gaussian Poisson distribution.
La productividad científica de los autores: Un modelo de aplicación de la ley de Lotka por el método del poder inverso generalizado
Urbizagástegui Alvarado,Rubén;
Informaci?3n, cultura y sociedad , 2005,
Abstract: the nature of the generalized inverse power distribution by the minimum least squared method is described. a step-by-step application process of this distribution model is offered. to illustrate the application process data collected and studied by oliveira on jackfruit literature was used. the generalized inverse power distribution by the minimum least squared method and the kolmogorov-smirnov test was used to evaluate the fit of the observed and expected data. with n = - 2.14 and c = 0.648715 at 0,01 level of significance, a critical value of 0.202177 with a maximum deviation of 0.151285, was observed. therefore, the literature fits lotka's model.
Elitismo na literatura sobre a produtividade dos autores
Alvarado, Rubén Urbizagástegui;
Ciência da Informa??o , 2009, DOI: 10.1590/S0100-19652009000200006
Abstract: the objective of this article is to identify and analyze the authors who make up the elite in a sub-area of the bibliometric field: the author's productivity is also known as the "lotka's law". the units of analysis were taken from 376 different authors producing of 390 articles, book chapters, and works presented in congresses, from 1922 up to 2003. the conclusion is that the elite was made up by 17 authors who had each one participated at least in the production of five or more documents totalizing a contribution of over a third of all documents.
A Lei de Lotka na bibliometria brasileira
Urbizagástegui Alvarado, Rubén;
Ciência da Informa??o , 2002, DOI: 10.1590/S0100-19652002000200002
Abstract: lotka's law, previously applied to brazilian national literature on ten different areas, were replicated. minimum square and maximum likelihood estimators were used. from those ten national literatures analyzed, only literatures in medicine, iron & steel, jackfruit, and library science did fit the generalized inverse power model when the method of minimum squared were used. all of them but two literatures (veterinary and getúlio vargas' private letters) did not fit the inverse power model when the maximum likelihood estimator were used. for these literatures different models were tested. veterinary literature did fit better to the negative binomial distribution, and getúlio vargas' private letters did fit better to the gaussian-poisson inverse generalized distribution.
La productividad científica de los autores: Un modelo de aplicación de la ley de Lotka por el método del poder inverso generalizado The scientific productivity of authors: an application model of Lotka's law by the generalized inverse power method
Rubén Urbizagástegui Alvarado
Información, Cultura y Sociedad , 2005,
Abstract: Describe la naturaleza de la distribución del poder inverso generalizado por el método de los mínimos cuadrados de la regresión lineal. Se describe paso a paso la forma de aplicación del modelo a los datos estudiados por Oliveira sobre la literatura de jaca. El modelo del poder inverso generalizado por el método de los mínimos cuadrados y la prueba Kolmogorov-Smirnov fueron usados para evaluar el ajuste de los datos observados y esperados. Con n = - 2.14, C = 0.648515 y al 0.01 nivel de significación, se verificó que el valor crítico fue de 0.202177 con un desvío máximo de 0.151285, por lo tanto, esta literatura se ajusta al modelo de Lotka. The nature of the generalized inverse power distribution by the minimum least squared method is described. A step-by-step application process of this distribution model is offered. To illustrate the application process data collected and studied by Oliveira on Jackfruit literature was used. The generalized inverse power distribution by the minimum least squared method and the Kolmogorov-Smirnov test was used to evaluate the fit of the observed and expected data. With n = - 2.14 and C = 0.648715 at 0,01 level of significance, a critical value of 0.202177 with a maximum deviation of 0.151285, was observed. Therefore, the literature fits Lotka's model.
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