1,721,802 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
Spontaneously stabilised dark matter from a fermiophobic U(1)′ gauge symmetry
No full textWe consider the possibility that dark matter is stabilised by a discrete Z2 symmetry which arises from a subgroup of a U(1)′ gauge symmetry, spontaneously broken by integer charged scalars, and under which the chiral quarks and leptons do not carry any charges. A chiral fermion χ with half-integer charge is odd under the preserved Z2, and hence becomes a stable dark matter candidate, being produced through couplings to right-handed neutrinos with vector-like U(1)′ charges, as in the type Ib seesaw mechanism. We calculate the relic abundance in such a low energy effective seesaw model containing few parameters, then consider a high energy renormalisable model with a complete fourth family of vector-like fermions, where the chiral quark and lepton masses arise from a seesaw-like mechanism. With the inclusion of the fourth family, the lightest vector-like quark can contribute to the dark matter production, enlarging the allowed parameter space that we explore
Fault-tolerant design and evaluation for a railway bogie active steering system
Full text linkActive suspension system can drastically improve dynamic behaviours of the railway vehicle but will also introduce safety-critical issues. The fault-tolerant analysis, therefore, is essential for the design and implementation of active suspension. However, this issue did not receive enough attention so far and only few papers can be found related to the fault tolerance of active steering for the railway vehicle. In this work, an approach based on Risk Priority Number is established to present quantitative assessment for fault tolerance of actuation system. Then this method is adopted to compare nine different active steering schemes resulting in a novel, comprehensive approach that enables a quantitative evaluation of different designs of the actuation system and of different principles to improve the fault tolerance. The impacts of typical failure modes are investigated through multi-body simulation and quantified by severity factor. Finally, the fault tolerance of different actuation schemes is evaluated by RPN values
An examination of alternative schemes for active and semi-active control of vertical car-body vibration to improve ride comfort
Full text linkThe recent tendency to reduce the weight of car bodies is posing a new challenge to vertical ride quality, since the vibrations related to car-body vertical bending modes affect heavily passengers’ comfort and cannot be fully mitigated by conventional vehicle suspensions. In this work, four mechatronic suspensions, considering active and semi-active technologies in secondary and primary suspensions, are compared to show their relative merits. LQG and H∞ model-based control strategies are established in a consistent way for each suspension scheme to perform a comparative assessment of the four concepts on objective grounds. A two-dimensional 9-DOF vehicle model is firstly built, using a simplified representation of car-body bending modes; this model is also used to design the model-based controllers. The comparison of the four mechatronic suspension schemes based on the 9-DOF model shows that full-active secondary suspension is the most effective solution whilst semi-active primary suspension is also effective in terms of mitigating car-body bending vibration. Then, a three-dimensional flexible multibody system (FMBS) vehicle model integrated with a finite-element car-body is considered to allow a more detailed consideration of the vehicle’s vibrating behaviour. The results of the FMBS model show a good agreement to the results of the 9-DOF model and the relative merits of the four mechatronic suspension schemes as found from the previous analysis are basically confirmed, although the FMBS model is more suited for a quantitative assessment of ride quality
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
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