1,720,994 research outputs found
Radioisotope identification using sparse representation with dictionary learning approach for an environmental radiation monitoring system
No full textA radioactive isotope identification algorithm is a prerequisite for a low-resolution scintillation detector applied to an unmanned radiation monitoring system. In this paper, a sparse representation with dictionary learning approach is proposed and applied to plastic gamma-ray spectra. Label-consistent K-SVD was used to learn a discriminative dictionary for the spectra corresponding to a mixture of four isotopes (133Ba, 22Na, 137Cs, and 60Co). A Monte Carlo simulation was employed to produce the simulated data as learning samples. Experimental measurement was conducted to obtain practical spectra. After determining the hyper parameters, two dictionaries tailored to the learning samples were tested by varying with the source position and the measurement time. They achieved average accuracies of 97.6% and 98.0% for all testing spectra. The average accuracy of each dictionary was above 96% for spectra measured over 2 s. They also showed acceptable performance when the spectra were artificially shifted. Thus, the proposed method could be useful for identifying radioisotopes in gamma-ray spectra from a plastic scintillation detector even when a dictionary is adapted to only simulated data. Furthermore, owing to the outstanding properties of sparse representation, the proposed approach can easily be built into an in-situ monitoring system.
Engineering Bacteroides thetaiotaoimcron to produce butyrate based on a genome-scale metabolic model-guided design
No full textMetal-Organic Framework-Derived Magnesium Oxide@Carbon Interlayer for Stable Lithium-Sulfur Batteries
No full textLithium sulfur (Li-S) batteries represent a promising future battery technology. However, the low electrical conductivity of solid-state sulfur species (S, Li2S2, and Li2S) and the polysulfide shuttle effect deteriorate their practical capacity and cycling retention. Herein, we present an interlayer composed of magnesium oxide (MgO) nanoparticles and carbon matrix for the Li-S batteries. In the composite, MgO can capture dissolved polysulfides that diffuse to the carbon matrix along the oxide surface for further reduction reactions. As a novel precursor to produce the composite structure, a Mg metal-organic-framework, Mg-MOF-74, is adopted and synthesized on a free-standing carbon paper (MOF/C-paper). Through pyrolysis, Mg-MOF-74 is converted into highly porous carbon containing uniformly distributed MgO nanoparticles (MgO@C/C-paper). The Li-S cells assembled with MgO@C/C-paper and C-paper interlayer show significantly higher initial capacities (980 and 898 mAh g-1, respectively) than the interlayer-free cell (729 mAh g-1) owing to the conductive interlayers. After 200 cycles at 0.2 C, the MgO@C/C-paper cell presents a cycle retention (78.3%) superior to that of the C-paper cell (76.5%). With a higher sulfur loading of 3.3 mg cm-2, the MgO@C/C-paper cell exhibits an even higher capacity retention (80.1%) than the C-paper cell (54.6%) after 100 cycles. The excellent cycle stability of the MgO@C/C-paper cell over the C-paper cell demonstrates that the unique structure of the MOF-derived MgO@C is highly effective in anchoring and reutilizing dissolved polysulfides.
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
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