1,721,101 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
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
Heat-accumulation stoves: numerical simulation of two twisted conduit configurations.
No full textAn important part of the society considers an increased share of renewable
energies as an integral part of a strategy towards a sustainable future. As far as heat supply is concerned, this can be achieved using solar thermal collectors, borehole heat exchangers or trough the combustion of biomass. This article shows two applications of two configurations of twisted conduit inside the external coating of the heat accumulation stoves. The hydrodynamic
flow is described by the k-є model, the buoyancy is taken into account, the heat transmission is treated into its three components: conductive, convective and radiative. The numerical results are compared with experimental measurements performed in the same configurations. The
experimental data were also used to determine the initial and boundary conditions of the numerical calculations. This research follows a multidisciplinary approach (numerical and physical modelling) to describe the
hydrodynamic flow and the heat exchanges between flue gas and the refractory material
Thermo-fluid dynamics of woody biomass flue gas in the heat accumulation stoves.
No full textThe research aims to clarify some aspects of the thermo-fluid dynamics of woody biomass flue gas within the refractory twisted conduit inside heat accumulation stoves. These are traditional heating elements in the European Alpine regions, whose history began in the fifteenth century. The high temperature flue gas flows in a twisted conduit, releasing heat along its path to the refractory. The heat stored in the refractory is then released slowly into the environment mainly as a radiant component. The physical phenomena that occur in an accumulation stove, once the activation energy in the combustion chamber has been provided, continues, initially increasing temperature and velocity of flue gases and then decreasing the two variables until the end of the reaction. The decreasing temperatures of flue gases,
flowing from the combustion chamber in the twisted conduit, tends to cause the transition of the flow regime from laminar to turbulent conditions. Moreover the continuous changes of direction imposed by the curves cause local contractions and expansions of the flux and, consequently, energy losses which are difficult to evaluate. The way the heat transfer occurs appears to depend mainly on gas flow conditions (laminar or turbulent) and on the radiative properties of the hot particle cloud inside the flue gas. The physical properties of the conduit (roughness of the internal surface), as well
as the thermodynamic properties of the refractory material (its mass and its geometric arrangement), play a fundamental role in the functionality of the stove. This paper describes some analysis performed on heat transport and exchange processes inside the flue gases and between them and the refractory. The importance of the radiation properties of the flue gasses has been highlighted. The numerical results, obtained with COMSOL® Non Isothermal Flow (k-epsilon turbulent model), have been compared with laboratory measures
Thermo-fluid dynamics of flue gas in heat accumulation stoves: study cases.
No full textThe research aims to clarify some aspects of the thermo-fluid dynamics of woody biomass flue gas, within the twisted conduit inside the heat accumulation stoves, and exposes also some analysis about the heat transport and heat exchange processes. The high temperature flue gas flows in the conduit, releasing heat to the refractory. The heat stored in the refractory is then released to the environment as radiant component. The physical phenomena that occur in an accumulation stove, once provided the activation energy in the combustion chamber, continue increasing temperature and velocity of flue gases and then decreasing the two variables. The decreasing temperatures of flue gases tends to cause the transition of the flow regime from laminar to turbulent conditions
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