1,720,954 research outputs found
Comparison of calibration of hyperspectral image-processing techniques for environmental assessment in S. Domingos Mine, SE Portugal
Full text linkTese apresentada à Universidade Técnica de Lisboa, Instituto Superior Técnico para a obtenção do grau de Doutor em Ciências de EngenhariaABSTRACT: This study addresses the application of hyperspectral or imaging spectroscopy (IS) sensors to environmental concerns related to mining areas and is tested in the old S. Domingos Mine. To detect for acid mine drainage a multi-source spectral methodology was developed based on distinct spectra: mineralogical libraries, field, and endmembers extracted from the images. A quantitative link is established among them, selecting the highest correlation values as input spectra for the Spectral Angle Mapper algorithm, generating two maps in function of either field or endmembers spectra. The final improved map is the pixel intersection of both, converted to high spectral correlations of mineralogical assemblages indicators of low pH (<3)[copiapite(coquimbite)(smectite-alunite-illite-kaolinite)]. The low pH areas vary in function of the atmospheric corrections and the thresholds selected, but generally assign the same critical hazardous areas in year 2000.
The monitoring capabilities were tested with another IS sensor seven years apart (2007) but the same methodology did not yield significant results, highlighting the complexity of a multi-sensor approach. The translation of input IS data resampled to a contemporary multispectral image mapped similar areas of low pH and opens good perspectives for multispectral routine application, once at some stage multi-source IS knowledge is available on a site.RESUMO: A aplicação de sensores hiper-espectrais ou de espectroscopia de imagens (EI) a questões ambientais relacionadas com áreas mineiras é testada na mina de S. Domingos. Para a detecção da drenagem ácida mineira, uma metodologia espectral multi-fonte é desenvolvida baseada em diferentes espectros: bibliotecas mineralógicas, campo e termos extremos extraídos das imagens. As correlações mais elevadas entre eles são seleccionadas para um algoritmo de Mapeamento de Ângulo Espectral gerando dois mapas em função de espectros de campo ou de termos extremos das imagens. O mapa final é a intersecção dos dois a nível de pixel, convertido em correlações elevadas de associações mineralógicas de baixo pH (<3)[copiapite(coquimbite)(esmectite-alunite-illite-caulinite]. Estas áreas de pH baixo variam em função das correcções atmosféricas e do valor de correlação, mas genericamente definem as mesmas áreas críticas de perigosidade no ano de 2000. As potencialidades de monitorização foram testadas com outro sensor EI (2007), mas a mesma metodologia não teve resultados significativos, evidenciando a complexidade duma abordagem multi-sensor. A translação de dados de EI para uma imagem multiespectral contemporânea mapeia áreas similares de baixo pH e abre boas perspectivas para a aplicação rotineira de dados multi-espectrais, uma vez que haja em algum período conhecimento multi-fonte de EI disponível.N/
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Geological mapping in the proterozoic Mt. Isa Inlier, Queensland, Australia, using radiometric and multispectral remotely sensed data
Full text linkLandsat Thematic Mapper, NSOOl Aircraft Thematic Mapper, Geoscan Mk. II. Multispectral Scanner and Airborne Gamma Radiometric data have been used to address a variety of geological problems in the Mary Kathleen area, 60 km east of Mt. Isa, NW Queensland. This area forms part of the Cloncurry Complex, a structurally complicated mass of diverse igneous and metamorphic rocks in the Precambrian Mt. Isa Inlier for which many stratigraphic problems remain to be solved. The Landsat Thematic Mapper data have been the most extensively used in this study. They are the least problematic data type and provide new geological information at scales up to 1:50 000. The NSOOl Aircraft Thematic Mapper data have similar spectral but superior spatial resolution in comparison with the satellite data. They suffer from increased geometric and noise-related problems, but the increase in spatial resolution has allowed the solution of problems, at scales up to 1:10 000, which could not be comprehensively addressed with the satellite data. The higher spectral resolution Geoscan Mk. II Multispectral Scanner aircraft data used in the latter part of the study can be used to remotely identify surface mineralogy. The logarithmic residual technique has proved the most successful approach to enhancing the radiance data sets. When applied to the lower spectral resolution data the technique achieves good discrimination of most lithologies, produces an albedo image useful for structural mapping and yields more information than can be extracted using conventional techniques. When applied to the higher spectral resolution data the technique allows remote mineral identification. Many of the geological problems in the area have been wholly or partially solved using suitably processed radiance data. The Airborne Gamma Radiometric data have the lowest spatial resolution. Only discrimination has been possible with this data set. These data contain no terrain information and are therefore difficult to use in the field. Integration of the gamma radiometric data with satellite data has been successful in overcoming this problem. The gamma radiometric data have allowed the separation of some lithologies which cannot be separated using the radiance data sets but have contrasting radiometric counts
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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