Text Mining Infrastructure in R

During the last decade text mining has become a widely used discipline utilizing statistical and machine learning methods. We present the tm package which provides a framework for text mining applications within R. We give a survey on text mining facilities in R and explain how typical application tasks can be carried out using our framework. We present techniques for count-based analysis methods, text clustering, text classification and string kernels.

Aplicación de Algoritmos de Clasificación de Minería de Textos para el Reconocimiento de Habilidades de E-tutores Colaborativos

Los sistemas de Aprendizaje Colaborativo Soportado por Computadora (ACSC) permiten el aprendizaje grupal con independencia del tiempo y espacio donde estén localizados los estudiantes y los docentes. Sin embargo, las interacciones que conducen a la creación colaborativa de conocimiento no surgen de manera espontánea y la tecnología puede inhibirlas u obstaculizarlas. Para colaborar efectivamente los estudiantes necesitan (entre otras cosas) de un e-tutor (docente) que coordine la interacción grupal. La selección de e-tutores capacitados es clave para el éxito del ACSC pero el análisis manual de las interacciones registradas en estos entornos para conocer el desempeño de los docentes requiere mucho tiempo y esfuerzo. En este artículo se describe un trabajo de investigación que aplica técnicas de minería de textos para crear clasificadores que permitan identificar automáticamente las habilidades manifestadas por e-tutores. Los resultados obtenidos mediante diferentes algoritmos de clasificación son presentados, analizados y comparados.Computer Supported Collaborative Learning (CSCL) systems enable group learning regardless of the time and space where students and teachers are located. However, interactions that conduct to collaborative creation of knowledge do not occur spontaneously and technology can inhibit or hinder them. Students need (among other things) of an e-tutor (teacher) that coordinates group interaction in order to effectively collaborate. Selection of qualified e-tutors is key for the success of CSCL, but manual analysis of interactions recorded in these environments to know the performance of teachers requires a lot of time and effort. This paper describes a research that applies text mining techniques to build classifiers that allow automatic identification of manifested skills by e-tutors. Results obtained by different classification algorithms are presented, analyzed and compared.Fil: Santana Mansilla, Pablo Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Santiago del Estero. Facultad de Ciencias Exactas y Tecnologías; ArgentinaFil: Costaguta, Rosanna Nieves. Universidad Nacional de Santiago del Estero. Facultad de Ciencias Exactas y Tecnologías; ArgentinaFil: Missio, Daniela. Universidad Nacional de Santiago del Estero. Facultad de Ciencias Exactas y Tecnologías; Argentin

The Early Pliocene extinction of the mega-toothed shark Otodus megalodon: a view from the eastern North Pacific

The extinct giant shark Otodus megalodon is the last member of the predatory megatoothed lineage and is reported from Neogene sediments from nearly all continents. The timing of the extinction of Otodus megalodon is thought to be Pliocene, although reports of Pleistocene teeth fuel speculation that Otodus megalodon may still be extant. The longevity of the Otodus lineage (Paleocene to Pliocene) and its conspicuous absence in the modern fauna begs the question: when and why did this giant shark become extinct? Addressing this question requires a densely sampled marine vertebrate fossil record in concert with a robust geochronologic framework. Many historically important basins with stacked Otodus-bearing Neogene marine vertebrate fossil assemblages lack well-sampled and well-dated lower and upper Pliocene strata (e.g., Atlantic Coastal Plain). The fossil record of California, USA, and Baja California, Mexico, provides such an ideal sequence of assemblages preserved within well-dated lithostratigraphic sequences. This study reviews all records of Otodus megalodon from post-Messinian marine strata from western North America and evaluates their reliability. All post-Zanclean Otodus megalodon occurrences from the eastern North Pacific exhibit clear evidence of reworking or lack reliable provenance; the youngest reliable records of Otodus megalodon are early Pliocene, suggesting an extinction at the early-late Pliocene boundary (∼3.6 Ma), corresponding with youngest occurrences of Otodus megalodon in Japan, the North Atlantic, and Mediterranean. This study also reevaluates a published dataset, thoroughly vetting each occurrence and justifying the geochronologic age of each, as well as excluding several dubious records. Reanalysis of the dataset using optimal linear estimation resulted in a median extinction date of 3.51 Ma, somewhat older than a previously proposed Pliocene-Pleistocene extinction date (2.6 Ma). Post-middle Miocene oceanographic changes and cooling sea surface temperature may have resulted in range fragmentation, while alongside competition with the newly evolved great white shark (Carcharodon carcharias) during the Pliocene may have led to the demise of the megatoothed shark. Alternatively, these findings may also suggest a globally asynchronous extinction of Otodus megalodon

Paleomagnetism of the Carboniferous-Permian Patquia Formation, Paganzo basin, Argentina: implications for the apparent polar wander path for South America and Gondwana during the Late Palaeozoic

The magnetic properties of the Carboniferous-Permian red beds of the Patquía Formation at Punta del Viento, Sierra de Umango and some previously reported localities, all in the Paganzo Basin (Argentina), have been studied. Whereas all sites are characterized by hematite as the main magnetic carrier and a reversed-polarity magnetic remanence, we found a pattern of variation in magnetic properties along the integrated column for Patquía Formation. The Lower Member (Late Carboniferous) showed higher intensity of natural and saturation isothermal remanent magnetisation (NRM and SIRM, respectively) than the Permian Upper Member. The fall in NRM intensity from the Lower to Upper Member of the Patquía Formation may be related to a change in quantity and/or grain-size of the hematite pigment, which may reflect the change in environmental and/or depositional setting. As for directional values of NRM, paleomagnetic poles reported for both sections are clearly different. The lower section provided a pole position coincident with Late Carboniferous poles for Gondwana, while the upper section poles are departed from the Early Permian position. We cannot decide whether the Upper Member pole is due to a primary magnetisation at 290 Ma or to a remagnetisation at ~260-270 Ma; even so, the obtained paleomagnetic pole is robust and indicates a rapid apparent polar wander in a ~30o counter clockwise rotation of the region, after deposition of the Late Carboniferous lower section, and in coincidence with the San Rafael Orogenic Phase

An application of the FIS-CRM model to the FISS metasearcher: Using fuzzy synonymy and fuzzy generality for representing concepts in documents

AbstractThe main objective of this work is to improve the quality of the results produced by the Internet search engines. In order to achieve it, the FIS-CRM model (Fuzzy Interrelations and Synonymy based Concept Representation Model) is proposed as a mechanism for representing the concepts (not only terms) contained in any kind of document. This model, based on the vector space model, incorporates a fuzzy readjustment process of the term weights of each document. The readjustment lies on the study of two types of fuzzy interrelations between terms: the fuzzy synonymy interrelation and the fuzzy generality interrelations (“broader than” and “narrower than” interrelations). The model has been implemented in the FISS metasearcher (Fuzzy Interrelations and Synonymy based Searcher) that, using a soft-clustering algorithm (based on the SISC algorithm), dynamically produces a hierarchical structure of groups of “conceptually related” documents (snippets of web pages, in this case)

Paleomagnetism of the Carboniferous-Permian Patquía Formation, Paganzo basin, Argentina: implications for the apparent polar wander path for South America and Gondwana during the Late Palaeozoic

The magnetic properties of the Carboniferous-Permian red beds of the Patquía Formation at Punta del Viento, Sierra de Umango and some previously reported localities, all in the Paganzo Basin (Argentina), have been studied. Whereas all sites are characterized by hematite as the main magnetic carrier and a reversed-polarity magnetic remanence, we found a pattern of variation in magnetic properties along the integrated column for Patquía Formation. The Lower Member (Late Carboniferous) showed higher intensity of natural and saturation isothermal remanent magnetisation (NRM and SIRM, respectively) than the Permian Upper Member. The fall in NRM intensity from the Lower to Upper Member of the Patquía Formation may be related to a change in quantity and/ or grain-size of the hematite pigment, which may reflect the change in environmental and/or depositional setting. As for directional values of NRM, paleomagnetic poles reported for both sections are clearly different. The lower section provided a pole position coincident with Late Carboniferous poles for Gondwana, while the upper section poles are departed from the Early Permian position. We cannot decide whether the Upper Member pole is due to a primary magnetisation at 290 Ma or to a remagnetisation at ~260-270 Ma; even so, the obtained paleomagnetic pole is robust and indicates a rapid apparent polar wander in a ~30o counter clockwise rotation of the region, after deposition of the Late Carboniferous lower section, and in coincidence with the San Rafael Orogenic Phase

A proposal of translation of Jabugo’s tourist portal into English

With the development of globalization, people are emphasizing the quality of online information which contributes to the development of tourism. Many people are not satisfied with inbound tourism and choose to travel abroad. Therefore, English translation seems to be essential. This work analyzes the importance of the English language and its role in the tourism sector. Included within the work is the introduction of the translation process, its methodology, and a final conclusio

Minería de datos aplicada a los precios de las subastas agrícolas de la Provincia de Almería

Fac. de Estudios EstadísticosTRUEpu