1,721,167 research outputs found
Some Strategy for Handling Measurement Biases in Inverse Problems with Application to Thermophysical Properties Identification
No full textThe influence of measurement biases on the estimation of thermophysical properties in transient experiments by means of inverse technique is analyzed. The material under investigation is subjected to a transient, one-dimensional conductive test. Then, from temperature and heat flux measurements on the boundary and at the interior of the specimen, the thermal conductivity and the specific heat are simultaneously reconstructed, as a function of temperature, by solving the associated inverse heat conduction problem. As well known, various systematic errors may affect measurements during the thermal transient with loss of accuracy in the identified thermophysical properties. In this work a strategy is proposed for handling some typical biases and many examples, coming both from numerical and true experiments, are reported and discussed. In particular the following three sources of error are considered and compensated: the uncertainty in the knowledge of the exact location of thermal sensors inside the specimen, the error of temperature measurement affecting the sensors (thermocouples) in dynamic regime and the statistical effect of the calibration uncertainty on the quality of the final estimates. In all cases the strategy adopted for handling the biases can be synthesized as follows: the improvement of the measurement process by adding appropriate physical models, to take into account each source of discovered error; the identification of the additional coefficients appearing in the models; the validation of the above procedure by means of proper indexes such as temperature or heat flux residuals, temperature dependent confidence regions of the estimated parameters, etc. The examples and the experimental results reported in this work refer to light insulating materials and show that a proper compensation of the effects of the above biases gives rise to a sensible improvement in the accuracy of the reconstructed thermophysical properties. Thermal conductivity and specific heat are reconstructed as a function of temperature with an accuracy comparable or even better than that obtainable with more consolidated standard methods
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
Modello ad impedenze di una cavità acustica cilindrica con isolamento tramite schiume smart auxetiche
No full textA method for the parametric frequency sensitivity in interior acousto-structural coupled system
No full textVariations 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
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