1,721,003 research outputs found
A stress-component-selective tactile sensor array
No full textA stress-component-selective tactile array, based on piezoelectric polymers, and its associated data acquisition system are described. The seven-taxel sensor array is made up of elements sensitive to one or more components of the stress field acting upon them. The six independent components of the stress tensor can be calculated from a linear combination of the responses of the six miniaturized elements composing each taxel. The array is developed with the aim of obtaining a skin-like tactile sensor able to perform fine-form discrimination of objects in contact with it. It is also thought to be instrumental in revealing phenomena related to incipient slippage during object manipulation and grasping. The multi-component sensor, based on 42 miniaturized piezoelectric polymer discs, is supported by a polyimide sheet with microlithographically defined electrodes. The sensor elements are embedded into a rubber layer with appropriate thickness in order to sample properly the stress field and to obtain good signal-to-noise ratio at the input of the electronic signal processing unit. Preliminary experiments to test the ability of individual sensor elements to resolve normal and shear stress components have shown good agreement with the responses predicted by analytical solutions of elastic contact problems
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
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
Piezoelectric properties of dry human skin
No full textMechanoelectrical conversion properties of dry human skin have been examined and their origin investigated in dermis, epidermis and horny layer. Shear stress piezoelectricity is observed in all three cutaneous sections. Piezoelectric properties of dermis can be ascribed to its collagen structural network, while the piezoelectric properties of epidermis appear to originate from partially oriented ¿-helical keratin-like tonofibrils. The highest piezoelectric coefficients have been found in horny layer samples. The values of thickness-compression piezoelectric coefficients were so low that they were not discernable from the intrinsic noise of the measuring system. Although thermally generated currents have been observed in the course of thermal pulse experiments, no evidence of relevant contributions from pyroelectric (polar) responses has been noticed in all cutaneous compartments
Approccio bionico allo sviluppo di trasduttori tattili ed attuatori lineari per robotica avanzata
No full textAlcuni fenomeni di traduzione meccanoelettrica in materiali organici di sintesi: proprietà e analogie con meccanismi di origine biologica
No full textShear stress detection in an elastic layer by a piezoelectric polymer tactile sensor
No full textA polyvinylidene fluoride (PVDF) sensor sandwiched between two elastic layers fixed to a rigid foundation is shown to be able to resolve a shear stress component produced by loading the upper layer's surface with a rigid indenter. When the measured charge response of the sensor is compared to that predicted by analytical solution of the corresponding axisymmetric elastic contact problem, a significant qualitative agreement between the two responses results. The experimentally determinated sensitivity, on the other hand, is found to be higher than that predicted analytically. Possible causes of this discrepancy are discussed
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