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41.
Fabio Aiolli Riccardo Cardin Fabrizio Sebastiani Alessandro Sperduti 《Information Retrieval》2009,12(5):559-580
In many applicative contexts in which textual documents are labelled with thematic categories, a distinction is made between
the primary categories of a document, which represent the topics that are central to it, and its secondary categories, which
represent topics that the document only touches upon. We contend that this distinction, so far neglected in text categorization
research, is important and deserves to be explicitly tackled. The contribution of this paper is threefold. First, we propose
an evaluation measure for this preferential text categorization task, whereby different kinds of misclassifications involving either primary or secondary categories have a different impact
on effectiveness. Second, we establish several baseline results for this task on a well-known benchmark for patent classification
in which the distinction between primary and secondary categories is present; these results are obtained by reformulating
the preferential text categorization task in terms of well established classification problems, such as single and/or multi-label
multiclass classification; state-of-the-art learning technology such as SVMs and kernel-based methods are used. Third, we
improve on these results by using a recently proposed class of algorithms explicitly devised for learning from training data
expressed in preferential form, i.e., in the form “for document d
i
, category c′ is preferred to category c′′”; this allows us to distinguish between primary and secondary categories not only in the classification phase but also
in the learning phase, thus differentiating their impact on the classifiers to be generated. 相似文献
42.
Alessandro N. Vargas Gisela Pujol Leonardo Acho 《Journal of The Franklin Institute》2017,354(1):332-344
The paper presents results for the second moment stability of continuous-time Markov jump systems with quadratic terms, aiming for engineering applications. Quadratic terms stem from physical constraints in applications, as in electronic circuits based on resistor (R), inductor (L), and capacitor (C). In the paper, an RLC circuit supplied a load driven by jumps produced by a Markov chain—the RLC circuit used sensors that measured the quadratic of electrical currents and voltages. Our result was then used to design a stabilizing controller for the RLC circuit with measurements based on that quadratic terms. The experimental data confirm the usefulness of our approach. 相似文献
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Roberto Assandri Silvia Accordino Ciro Canetta Elisabetta Buscarini Alessandro Scartabellati Chiara Tolassi Federico Serana 《Biochemia medica : ?asopis Hrvatskoga dru?tva medicinskih biokemi?ara / HDMB》2022,32(2)
IntroductionSeveral laboratory tests are characteristically altered in Coronavirus Disease 2019 (COVID-19), but are not totally accurate in predicting the disease outcome. The long pentraxin 3 (PTX3) is quickly released directly at inflammation sites by many immune cell types. Previous studies have shown that PTX3 correlated with disease severity in various inflammatory conditions. Our study investigated the use of PTX3 as a potential marker of COVID-19 severity and compared its performance in detecting a more severe form of the disease with that of routine laboratory parameters.Materials and methodsStored serum samples of RT-PCR confirmed COVID-19 cases that had been obtained at hospital admission were retrospectively analysed. Intensive care unit (ICU) stay was considered a surrogate endpoint of severe COVID-19. Pentraxin 3 was measured by a commercial enzyme-linked immunosorbent assay.ResultsA total of 96 patients were recruited from May 1st, 2020 to June 30th, 2020; 75/96 were transferred to ICU. Pentraxin 3 was higher in ICU vs non-ICU patients (35.86 vs 10.61 ng/mL, P < 0.001). Univariate and multivariate logistic regression models demonstrated that the only significant laboratory predictor of ICU stay was PTX3 (OR: 1.68 (1.19-2.29), P = 0.003), after controlling for comorbidities. The Receiver Operator Characteristic curve analysis showed that PTX3 had a higher accuracy compared to C-reactive protein (CRP), lactate dehydrogenase (LD), ferritin in identifying ICU patients (AUC of PTX3 = 0.98; CRP = 0.66; LD = 0.70; ferritin = 0.67, P < 0.001). A cut-off of PTX3 > 18 ng/mL yielded a sensitivity of 96% and a specificity of 100% in identifying patients requiring ICU.ConclusionHigh values of PTX3 predict a more severe COVID-19. 相似文献
45.
Pietro Boscolo 《European Journal of Psychology of Education - EJPE》1991,6(2):167-174
The role of context variables is emphasized in recent research on writing, from which a great variety of meanings of the word ‘context’ emerges. The aim of this paper is to investigate some aspects of the identification of context variables in writing research by focusing on three main functions of context:
- context as a condition for communication, i.e. the ground the writer creates in order to communicate with the reader
- context as task environment, i.e. the situational variables (task objectives, motivational aspects, media, etc.) which can influence the writing process and/or product
- context as an interactive framework, i.e. context as constituted by what people are doing, as well as by when and where they are doing it.
46.
The central question asked was whether differential shock modification occurs (posturally induced differences in shock contact time) under signaled and unsignaled conditions using scrambled shock. Shock modifiability was tested with two different shock sources, intensities, and scrambling units by measuring the duration of time subjects were in contact with shock. Subjects were then given a choice between the signaled and unsignaled conditions. Results showed that differential modification of shock contact time did not occur between signaled and unsignaled conditions with any shock source, intensity, or scrambler unit. In addition, subjects preferred the signaled condition. It was concluded that experiments using scrambled shock are not confounded by posturally induced differences in shock contact time. 相似文献
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48.
Pietro Cerreta 《Science & Education》2014,23(4):747-760
The Gravity-Powered Calculator is an exhibit of the Exploratorium in San Francisco. It is presented by its American creators as an amazing device that extracts the square roots of numbers, using only the force of gravity. But if you analyze his concept construction one can not help but recall the research of Galileo on falling bodies, the inclined plane and the projectile motion; exactly what the American creators did not put into prominence with their exhibit. Considering the equipment only for what it does, in my opinion, is very reductive compared to the historical roots of the Galilean mathematical physics contained therein. Moreover, if accurate deductions are contained in the famous study of S. Drake on the Galilean drawings and, in particular on Folio 167 v, the parabolic paths of the ball leaping from its launch pad after descending a slope really actualize Galileo’s experiments. The exhibit therefore may be best known as a ‘Galilean calculator’. 相似文献
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Mellone Maria Ramploud Alessandro Carotenuto Gemma 《Educational Studies in Mathematics》2021,106(3):379-396
Educational Studies in Mathematics - We will present cultural transposition as a particular perspective to frame the use of foreign mathematics education practices as an opportunity for questioning... 相似文献