1,720,997 research outputs found
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
Dynamic modelling of floating wind turbines
No full textFloating Wind Turbines (FWTs) offer a promising solution to harnessing substantial offshore wind energy in deep waters. However, accurately modelling their complex dynamics is challenging due to the complex coupling between aerodynamics, hydrodynamics, structural elasticity, and controls. This thesis proposes an integrated FWT simulation framework in Simulink to investigate these dynamics, with a particular focus on nonlinear wave-platform interactions induced by large platform motions.
A comprehensive FWT model is developed in Simulink, featuring efficient state-space representations for linear wave radiation and excitation effects, a multibody formulation to account for large geometrically nonlinear blade deformations, a modified blade-element momentum method for unsteady aerodynamics, and a multi-loop ROSCO control strategy for power regulation and platform stabilization. Validation against the widely-used OpenFAST simulation tool demonstrates the ability of the developed Simulink model to capture the dominant FWT dynamic couplings under realistic environmental conditions.
To address the limitations of the conventional linear hydrodynamic model, which assumes small platform motion around the equilibrium position, an analytical solution to the 2D linear wave-platform boundary value problem (BVP) linearized at an arbitrary platform pose is proposed. The analytical method is compared against a numerical boundary element method, and the influence of platform pose on the hydrodynamic behaviour is investigated.
Additionally, a novel linear parameter varying (LPV) modelling framework is developed to capture the geometrically nonlinear wave radiation effect. The LPV system is constructed using state-space models identified from the BVPs linearized at various platform positions, with the instantaneous platform pose used to interpolate the state-space matrices. To ensure state-basis coherency across all linear models, a black-box method based on the balanced realization and a gray-box method that ties the state vector to physical parameters are proposed. Both LPV models are validated on the benchmark van Daalen floating cylinder, and they are then integrated into the Simulink FWT model. Results indicate that the LPV models effectively capture nonlinear hydrodynamic effects and offer significant computational efficiency, making them practical for early-stage FWT design and optimization
Inertial fragmentation processes associated with ocean wave breaking
Full text linkOcean sprays are liquid droplets ejected from the sea surface, which enhance mass, momentum and energy transfer at the air-sea interface. Depending on their sizes, ocean sprays interact with their environment and influence the global climate system differently. They are produced from breaking ocean waves through a few dominant mechanisms, including film and jet drops associated with bursting surface bubbles, spume drops sheared from wave crests under high winds, and splash drops due to the collapse of corrugated wave fronts. Here, we use the open-source numerical solver Basilisk to investigate the latter two spray generation mechanisms, which remain poorly understood due to difficulties in the detailed analysis of breaking waves. Due to the extremely high computational cost of resolving all spray production events during wave breaking, we instead investigate two canonical fragmentation configurations as toy models for ocean spray generation, namely the bag breakup of droplets in airflows and the transverse collision of liquid rims.
For droplet aerobreakup, we utilise a recently proposed Manifold Death (MD) algorithm to artificially perforate thin liquid films in a controlled manner, establishing numerical grid convergence of the statistics of large fragments for the first time. We then analyse different fragmentation mechanisms leading to bag film rupture and discuss their contribution to fragment statistics. We further implement the Synthetic Turbulence Generation Method to investigate the influence of air-phase turbulence on the early-time evolution of bag morphology, where the decrease in droplet aspect ratio, late-time tilting of the bag and formation of small-scale surface corrugations are systematically measured and analysed.
As for rim collision, we identify ligament merging as the dominant underlying mechanism causing the increase of the size of splash drops over time, and establish a quasi-steady theoretical framework capable of predicting the long-term fragment size and velocity distributions. Gravity arrests the ligament merging process by pulling back the liquid lamella arising from rim coalescence. The size and velocity distributions of the splash drops compare favourably with available wave-breaking data, and we propose a novel theoretical model accounting for the time evolution in the rim fragment size distribution. We further propose sea spray generation functions corresponding to splash drops produced from realistic sea states. Our discovery of fragmenting large splash drops challenges the previous speculation that wave splashing is an inefficient sea spray generation mechanism, thus bearing far-reaching implications for modelling efforts in air-sea interaction. Overall, the numerical results and physical insights obtained here serve as a stepping stone towards fully understanding ocean spray formation with the aid of two phase direct numerical simulations
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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