1,720,962 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
Time-domain simulation of seakeeping and manoeuvring of ships in deep and shallow water waves
Get PDFThe present thesis deals with the topic of ship manoeuvring in waves and the effects imposed by the shallow water. In this aspect, ship's manoeuvrability is investigated using a numerical method, which was developed according to a hybrid approach where seakeeping and manoeuvring contributions are blended. In order to ensure that the aforementioned model incorporates correctly seakeeping and calm water manoeuvring approaches, separate validation processes are followed beforehand. In case of nonlinear seakeeping analysis, parametric roll investigation is undertaken as well, as a mean to verify that the developed methodology evaluates properly the fundamental external forces, especially roll damping. In this way, a framework is established which offers the ability to perform holistic hydrodynamic assessment of marine vessels as well.;Validation of the developed computational code is conducted using experimental turning circle trajectories, which refer to deep water conditions. The case studies concern the horizontal motions of the S-175 container ship at long waves and four values of under keel clearance corresponding to medium-deep (UKC=3.0, 2.5, 2.0) and shallow waters (UKC=1.5). In this aspect, the wave forces as well as the manoeuvring-related ones are corrected using relevant methodologies. In particular, a 3D potential flow method is adopted for the evaluation of the former, whilst corrections are applied on the various manoeuvring-related force components defined by the Manoeuvring Modelling Group (Ogawa et al., 1977). Especially in case of the added resistance, near and far-field methods are implemented based on the size of the wavelength with respect to the ship's length.;The empirical corrections which refer to the manoeuvring-related forces and are used in order to incorporate the shallow water effect, concern the hydrodynamic hull forces, the calm water resistance and various hull-rudder-propeller interaction coefficients and are based on regression formulae which are functions of the under keel clearance ratio.The present thesis deals with the topic of ship manoeuvring in waves and the effects imposed by the shallow water. In this aspect, ship's manoeuvrability is investigated using a numerical method, which was developed according to a hybrid approach where seakeeping and manoeuvring contributions are blended. In order to ensure that the aforementioned model incorporates correctly seakeeping and calm water manoeuvring approaches, separate validation processes are followed beforehand. In case of nonlinear seakeeping analysis, parametric roll investigation is undertaken as well, as a mean to verify that the developed methodology evaluates properly the fundamental external forces, especially roll damping. In this way, a framework is established which offers the ability to perform holistic hydrodynamic assessment of marine vessels as well.;Validation of the developed computational code is conducted using experimental turning circle trajectories, which refer to deep water conditions. The case studies concern the horizontal motions of the S-175 container ship at long waves and four values of under keel clearance corresponding to medium-deep (UKC=3.0, 2.5, 2.0) and shallow waters (UKC=1.5). In this aspect, the wave forces as well as the manoeuvring-related ones are corrected using relevant methodologies. In particular, a 3D potential flow method is adopted for the evaluation of the former, whilst corrections are applied on the various manoeuvring-related force components defined by the Manoeuvring Modelling Group (Ogawa et al., 1977). Especially in case of the added resistance, near and far-field methods are implemented based on the size of the wavelength with respect to the ship's length.;The empirical corrections which refer to the manoeuvring-related forces and are used in order to incorporate the shallow water effect, concern the hydrodynamic hull forces, the calm water resistance and various hull-rudder-propeller interaction coefficients and are based on regression formulae which are functions of the under keel clearance ratio
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
Ship's hull response under extreme bending loading
No full textΕθνικό Μετσόβιο Πολυτεχνείο--Μεταπτυχιακή Εργασία. Διεπιστημονικό-Διατμηματικό Πρόγραμμα Μεταπτυχιακών Σπουδών (Δ.Π.Μ.Σ.) “Υπολογιστική Μηχανική
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
Time-domain simulation of the maneuvering performance of ships in regular waves and shallow water
Get PDFThe IMO's Second Generation of Intact Stability Criteria (SGISC) have brought the manoeuvring performance of ships in waves to the spotlight of the research community. A very interesting case arises when the vessel's manoeuvrability is affected by shallow water as well. As this instance is rather common closer to shore and in the proximity of ports, any degradation of the vessel's ability to execute the commanded manoeuvres may give rise to safety concerns. The authors present herein a novel hybrid methodology that captures such changes in the ship's manoeuvring performance. It accounts for the influence of both the first and second-order wave forces, as well as on the calm water-related contributions. This hybrid seakeeping and manoeuvring methodology has been programmed into the time-domain simulation software ELIGMOS and it is tested with the S-175 container ship, investigating the impact on her turning circle manoeuvres in long regular waves (λ/L=1.0) at a Froude number of 0.15 and various under keel clearance values. The steady drift forces in shallow water have been calculated using a near-field methodology, embedded in the NEWDRIFT 3D-panel code. Using Ankudinov's formulae, the impact of shallow water on the manoeuvring derivatives has been captured. The authors present analytically the results and discuss their findings
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