1,720,970 research outputs found
An ensemble agglomerative hierarchical clustering algorithm based on clusters clustering technique and the novel similarity measurement
No full textThe advent of architectures such as the Internet of Things (IoT) has led to the dramatic growth of data and the production of big data. Managing this often-unlabeled data is a big challenge for the real world. Hierarchical Clustering (HC) is recognized as an efficient unsupervised approach to unlabeled data analysis. In data mining, HC is a mechanism for grouping data at different scales by creating a dendrogram. One of the most common HC methods is Agglomerative Hierarchical Clustering (AHC) in which clusters are created bottom-up. In addition, ensemble clustering approaches are used today in complex problems due to the weakness of individual clustering methods. Accordingly, we propose a clustering framework using AHC methods based on ensemble approaches, which includes the clusters clustering technique and a novel similarity measurement. The proposed algorithm is a Meta-Clustering Ensemble scheme based on Model Selection (MCEMS). MCEMS uses the bi-weighting policy to solve the model selection associated problem to improve ensemble clustering. Specifically, multiple AHC individual methods cluster the data from different aspects to form the primary clusters. According to the results of different methods, the similarity between the instances is calculated using a novel similarity measurement. The MCEMS scheme involves the creation of meta-clusters by re-clustering of primary clusters. After clusters clustering, the number of optimal clusters is determined by merging similar clusters and considering a threshold. Finally, the similarity of the instances to the meta-clusters is calculated and each instance is assigned to the meta-cluster with the highest similarity to form the final clusters. Simulations have been performed on some datasets from the UCI repository to evaluate MCEMS scheme compared to state-of-the-art algorithms. Extensive experiments clearly prove the superiority of MCEMS over HMM, DSPA and WHAC algorithms based on Wilcoxon test and Cophenetic correlation coefficient
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
Fabrication of Graphene Sheets Using an Atmospheric Pressure Thermal Plasma Jet System
No full textThe mass production of cost-effective, large area, defect-free and high crystal quality graphene sheets with a high yield is a challenging task. In order to investigate the mechanisms involved, we report on the synthesis of graphene sheets by a homemade atmospheric pressure thermal plasma jet system, which is a single-step and less time-consuming technique. The samples were prepared by using pure Ar gas and a mixture of Ar and N2. The microstructure of the synthesized graphene sheets was characterized with the help of Raman spectroscopy, field emission scanning electron microscopy (FE-SEM) and Fourier transform infrared (FTIR) spectroscopy. The appearance of G and 2D peaks in the Raman spectrum confirmed the formation of graphene. Moreover, we observed that the addition of nitrogen increased the production of the graphene sheets but compromised the quality of those graphene sheets by increasing their structural defects. The morphology of the synthesized samples studied via FE-SEM images showed that the sheets were composed of multilayers. FTIR spectra show the presence of C=C and a hydroxyl group directly bonded to the aromatic hydrocarbon
RETRACTED: Measure and evaluate the hydrothermal flow of a Newtonian fluid in homogeneous permeable media equipped with a fin: A numerical approach
Full text linkThis study envisions the hydrothermal characteristics of a viscous fluid in a homogenously permeable hexagonal enclosure. Permeability aspects in the flow domain are described by employing the Brinkman-extended Darcy law. A corrugated hexagonal enclosure along with the placement of a star-shaped fin is taken into account. Heated rectangular blocks at horizontal extremities are installed, and sliding sides of the enclosure are considered to be cold to provide convective potential to the flow. In addition, adjoining portions of the heated rectangular blocks are supposed to be adiabatic. The dimensionless governing equations of the resultant problem are derived initially and then solved numerically by implementing the Galerkin finite element approach, and COMSOL is obliged. For this purpose, first, domain discretization is demonstrated in view of 2D elements by performing hybridized meshing. Then, the system of non-linear equations is resolved by a non-linear solver (PARADISO). The grid convergence test is performed to confirm the credibility of the carried out simulations by calculating the average Nusselt number at different refinement levels. A change in associated distributions against the involved physical parameters (Darcy number (Da), Rayleigh number (Ra), and Prandtl number (Pr)) for a wide range is revealed through graphs and tables. Quantities like kinetic energy and heat flux (local and average) are also evaluated through concerned parameters. The results clearly demonstrate that the Darcy number tends to reduce the heat transfer rate. In particular, it is depicted that by increasing the Rayleigh number (Ra), strengthening in the temperature potential arises in the system, thereby magnifying the heat transfer rate. Moreover, it is disclosed that by reducing the Darcy number, kinetic energy shows a decreasing trend
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