1,721,556 research outputs found
The Design, Fabrication and Preliminary Testing of a Variable Configuration Mobile Robot
Full text linkIn this paper a novel low cost mobile robot that can adjust the balance between the energy efficiency and the running performance according to the environment by changing the number of wheels is introduced. The developed robot, which can be constructed by combining the modules and is driven by Robot Operating System (ROS) tools, has a 3D light detection and distance measurement (LiDAR) for generation of 3D digital map and travels through several environment with saving the energy by adaptively changing the number and arrangement of the wheels according to the environment. The robot can easily change the three types of mechanisms by changing the number of modularized driving wheels and their combination. Furthermore, the developed robot can construct a 3D map in a rough outdoor environment and the running performance of three kinds of robots was investigated by an extensive characterization. Finally, the limits of this prototype have been meticulously analyzed, highlighting new improvements in the future perspective development for permitting an autonomous environment perception with a simple, modular and low-cost device
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
Grain size influence on residual stresses in alumina/zirconia composites
No full textThe grain size (GS) and volume fraction of alumina have been systematically varied in composites with a zirconia matrix and the corresponding residual stresses have been assessed by means of piezo-spectroscopy. The compressive stress in alumina depends on the volume fraction and it is well predicted by a stochastic model based on information theory. No dependence with GS has been detected, except at the highest volume content (20% vol. alumina). Conversely the stress distribution is independent from the volume fraction and depends on GS: intermediate values of GS exhibit the wider stress distribution. The tensile stress in zirconia shows no clear correlation with the volume fraction and increases with increasing zirconia GS. This latter behaviour has been compared with a model based on diffusional relaxation of stresses. The model reproduces correctly the stress change due to different alumina contents, but it diverges from the experimental data at smaller GSs, overestimating the residual stress. It is suggested that grain boundary sliding may also contribute to the relaxation of stresses
Stress dependence of the raman spectrum of β-silicon nitride
No full textThe stress dependence of the Raman bands of β-silicon nitride, β-Si3N4, has been investigated. In the stress range examined (from -200 to +200 MPa), low-frequency shift bands (namely the 183, 205, and 226 cm-1 lines) do not show any frequency change with the stress, whereas the highfrequency shift bands (862, 925, and 936 cm-1) have been found to have a linear stress dependence. The pertinent piezo-spectroscopic coefficients have been determined and are found to depend strongly on the additives used to promote densification presumably being taken into solid solution into the β-Si3N4 phase
Measurement of microscopic bridging stresses in Al2O3/Molybdenum composite by in situ fluorescence spectroscopy
No full textAppropriate 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
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