1,720,963 research outputs found
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
Systems based on aluminum complex metallic alloys: development, characterization and surface properties
No full textComplex metallic alloys (CMAs) is a new category of metallic materials that are characterized by very large unit cells that contain a substantial number of atoms and very big lattice parameters. CMAs exhibit a lot of attractive properties such as high hardness, low friction coefficient and high resistance to oxidation. Their application has been restricted by a major drawback, their low ductility at room temperature. A feasible way to overcome this limitation is to use CMAs as reinforcement in a ductile matrix. Some known CMAs are: Al-Cu-Fe, Al-Cu-Fe-Cr, Al-Cr-Fe, Al13Co4, Al9Co2. This thesis is focused on Al-Al9Co2 system (Al-Co alloys). The main objective of this effort is to study the influence of the preparation method on the microstructure and surface degradation properties of Al-Co alloys. Moreover, to study a wide range of Al-Co compositions as far as their microstructure, corrosion resistance and wear resistance are concerned. Al-Co alloys of various compositions (2-20 wt.% Co) were prepared by casting, vacuum arc melting and powder metallurgy. Their microstructure was studied by Χ-ray diffraction, optical microscopy and scanning electron microscopy. Corrosion behaviour was evaluated by potentiodynamic polarization and chronoamperometry measurements in 3,5% NaCl and 1M H2SO4. Sliding wear experiments were performed to evaluate the wear performance of Al-Co alloys. For comparison reasons, the corrosion behaviour, sliding wear resistance of pure aluminum, widely used aluminum alloys and industrial alloys were evaluated. The preparation method and composition heavily affect the attained microstructures. However, regardless of the preparation method, all Al-Co alloys exhibited high resistance to localized forms of corrosion in all studied environments. Furthermore, Al-Co alloys exhibited better sliding wear performance compared to widely used commercial aluminum alloys. It is worth noticing that Al-Co alloys with modest Co compositions had significantly improved resistance to surface degradation compared to aluminum alloys. Corrosion and sliding wear mechanisms were formulated.Τα πολύπλοκα μεταλλικά κράματα (Complex Metallic Alloys) αποτελούν μια νέα κατηγορία μεταλλικών υλικών που χαρακτηρίζονται από πολύπλοκη κρυσταλλική δομή και μεγάλες μοναδιαίες κυψελίδες. Εμφανίζουν ελκυστικές ιδιότητες όπως υψηλή σκληρότητα, χαμηλό συντελεστή τριβής και υψηλή αντίσταση σε οξείδωση. Παρόλα αυτά, η εφαρμογή τους είναι περιορισμένη λόγω της χαμηλής ολκιμότητας που εμφανίζουν σε θερμοκρασία δωματίου. Ένας πιθανός τρόπος να ξεπεραστεί αυτός ο περιορισμός είναι να χρησιμοποιηθούν σαν ενίσχυση σε μια όλκιμη μήτρα. Ορισμένα γνωστά πολύπλοκα μεταλλικά κράματα είναι τα Al-Cu-Fe, Al-Cu-Fe-Cr, Al-Cr-Fe, Al13Co4, Al9Co2. Στα πλαίσια αυτής της διατριβής μελετήθηκε το σύστημα Al-Al9Co2 (κράματα Al-Co). Βασική επιδίωξη αυτής της ερευνητικής προσπάθειας ήταν να μελετηθεί η επίδραση της μεθόδου παρασκευής αλλά και της σύστασης των μελετώμενων κραμάτων, στη μικροδομή και την αντίσταση σε επιφανειακή υποβάθμιση του συστήματος. Επιπρόσθετα, να προσδιοριστεί η χαμηλότερη δυνατή σύσταση κοβαλτίου που οδηγεί σε βελτιωμένη αντίσταση σε επιφανειακή υποβάθμιση. Παρασκευάστηκαν κράματα Al-Co με διαφορετικές συστάσεις (2-20 %κ.β. Co) με χύτευση, τήξη τόξου και κονεομεταλλουργία. Η μικροδομή τους αξιολογήθηκε με περίθλαση ακτίνων-Χ, οπτική μικροσκοπία και ηλεκτρονική μικροσκοπία σάρωσης. Η συμπεριφορά σε διάβρωση των παραχθέντων κραμάτων αξιολογήθηκε με ποτενσιοδυναμικές πολώσεις και μετρήσεις χρονοαμπερομετρίας σε υδατικά διαλύματα 3,5% NaCl, 1M H2SO4. Επιπλέον, αξιολογήθηκε η απόκριση των κραμάτων Al-Co σε φθορά ολίσθησης. Για λόγους σύγκρισης αξιολογήθηκε η συμπεριφορά σε διάβρωση και φθορά ολίσθησης καθαρού αλουμινίου, ευρέως χρησιμοποιούμενων κραμάτων αλουμινίου και άλλων βιομηχανικών κραμάτων. Σύμφωνα με τα ευρήματα, η μέθοδος παρασκευής και η σύσταση των κραμάτων Al-Co επηρεάζουν έντονα την παρατηρούμενη μικροδομή. Σε κάθε περίπτωση, ανεξαρτήτως της μεθόδου παρασκευής και της σύστασης, τα κράματα Al-Co εμφάνισαν χαμηλή επιδεκτικότητα σε τοπικές μορφές διάβρωσης σε όλα τα εξεταζόμενα περιβάλλοντα. Επιπρόσθετα, τα κράματα Al-Co παρουσίασαν υψηλότερη αντίσταση σε φθορά ολίσθησης σε σχέση με ευρέως χρησιμοποιούμενα κράματα αλουμινίου. Αξίζει να τονιστεί ότι τα κράματα Al-Co με σχετικά χαμηλή περιεκτικότητα σε κοβάλτιο εμφάνισαν σημαντικά βελτιωμένη αντίσταση σε επιφανειακή υποβάθμιση σε σχέση με ευρέως χρησιμοποιούμενα κράματα αλουμινίου. Έλαβε χώρα ανάλυση των μηχανισμών διάβρωσης και φθοράς ολίσθησης για τα μελετώμενα κράματα Al-Co
Development of a water pollution prediction model using a multi-parameter sensors network
No full textA network of three multi-parametric sensor systems was installed and studied for monitoring the quality characteristics of the water resources in the region of Ptolemaida lignite mines of PPC SA for a period of about 10 months (March-December 2010). The physicochemical parameters measurements (temperature, pH, conductivity, Cl-, SO4-2, NO3-) after being checked for their reliability, they were processed based on specific statistical techniques and related with each other, as well as with other parameters such as rainfall and volumetric flow drainage of lignite mines in surface water (Soulou stream), in order to examine statistically significant correlations for the detection / prediction of potential pollution incidents.The developed models presented quite satisfactory level of reliability and predictive ability; however, utilization of this methodology should be carried out by taking into account certain limitations, such as non-predictable external factors and other restrictions related to the field research (e.g. discontinuity of data).Στα πλαίσια της παρούσας διδακτορικής διατριβής εγκαταστάθηκε και μελετήθηκε ένα δίκτυο αποτελούμενο από τρία συστήματα πολυπαραμετρικών αισθητήρων για τη συνεχή παρακολούθηση των ποιοτικών χαρακτηριστικών των υδατικών πόρων εντός της ευρύτερης περιοχής των ορυχείων λιγνίτη Πτολεμαΐδας της ΔΕΗ Α.Ε. για μια περίοδο περίπου 10 μηνών (Μάρτιος – Δεκέμβριος 2010). Τα αποτελέσματα των φυσικοχημικών παραμέτρων που μετρήθηκαν (θερμοκρασία, pH, αγωγιμότητα, Cl-, SO4-2, NO3-) αφού πρώτα ελέγχθηκαν για την αξιοπιστία τους, στη συνέχεια υπέστησαν επεξεργασία με βάση συγκεκριμένες στατιστικές τεχνικές και συσχετίσθηκαν τόσο μεταξύ τους όσο και με άλλες παραμέτρους όπως τη βροχόπτωση και τις ογκομετρικές παροχές από τις εκροές των αντλιοστασίων ορυχείων στα επιφανειακά ύδατα (ρέμα Σουλού), με στόχο τη διερεύνηση στατιστικά σημαντικών συσχετίσεων για τον εντοπισμό/πρόβλεψη ενδεχόμενων επεισοδίων ρύπανσης. Η μεθοδολογία που αναπτύχθηκε παρουσιάζει αρκετά ικανοποιητικό βαθμό αξιοπιστίας και προβλεπτικής ικανότητας, λαμβάνοντας πάντα υπόψη μη προβλέψιμους εξωγενείς παράγοντες καθώς και λοιπούς περιορισμούς που εμφανίζει η έρευνα πεδίου (π.χ. ασυνέχεια μετρήσεων)
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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