1,721,005 research outputs found
Integrazione di metodi numerici e sperimentali: una prospettiva biomeccanica
No full textAbstract. La biomeccanica dell’osso è stata ampiamente studiata in passato sia con esperimenti in vitro, che con modelli numerici. Nella maggior parte dei casi viene scelto uno dei due approcci, senza sfruttare le sinergie. Sia gli esperimenti che i modelli numerici soffrono di limitazioni relative alla loro accuratezza e ai rispettivi campi di applicazione. Gli esperimenti in vitro sono in grado di migliorare i modelli numerici tramite: (i) l’individuazione dei più importanti scenari di fallimento, (ii) identificazione del modello con le proprietà dei materiali misurati sperimentalmente, (iii) validazione quantitativa basata sulle proprietà meccaniche (deformazione, spostamenti) misurate direttamente da campioni fisici da testare in parallelo all’attività modellazione. Analogamente, i modelli numerici possono migliorare gli esperimenti in vitro: (i) identificando le più rilevanti configurazioni di carico tra un certo numero di compiti motori che non possono essere replicati in vitro, (ii) identificando semplificazioni accettabili per la simulazione in vitro; (iii) ottimizzando l’uso di trasduttori per minimizzare gli errori e fornire misurazioni nei punti più rilevanti, (iv) esplorando una varietà di condizioni diverse (proprietà dei materiali, interfaccia, ecc), che richiederebbe un enorme sforzo sperimentale. Prendendo ad esempio uno studio del femore, si mostra come una combinazione di modellazione numerica ed esperimenti controllati all’interno dello stesso gruppo di ricerca può essere progettato per creare un circolo virtuoso in cui vengono utilizzati i modelli per migliorare gli esperimenti, gli esperimenti sono utilizzati per migliorare i modelli, e la loro combinazione offre in sinergia risultati più dettagliati e più affidabili di quanto possa ottenersi utilizzando singolarmente uno dei due approcci
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
Rotation axis identification at the human tibio-talar and talo-calcaneal joints by the Burmester theory
No full textA correct identification of the human joint rotation axes is important in several applications, such as prosthesis and exoskeleton design, and multibody modelling of the human body. This identification is particularly difficult at the ankle joint, where two different articulations are observed, namely the tibio-talar joint (connecting the tibia and talus) and the talo-calcaneal joint (connecting the talus and calcaneus). The motion of both these joints could be approximated to some extent with a rotation about a single axis; thus, the ankle requires the identification of two distinct axes in order to correctly describe the joint motion. A new method is proposed in this study for the identification of the tibio-talar and talo-calcaneal rotation axes that does not require the measure of the talus motion. This feature is particularly important for in vivo measurements, since non-invasive experimental techniques do not allow the talus motion to be obtained, due to the inaccessibility of this bone. The method also exhibits other advantages: the rotation axes are identified simultaneously and thus their identification accuracy is independent; the method is not based on optimization techniques and thus it does not require the definition of an objective function; it is robust; it makes it possible to obtain the talus motion. The theoretical bases of the method are presented and a case study is used to assess the potentiality of the identification procedure
Under-Constrained Cable-Driven Parallel Robots
No full textThis paper studies cable-driven parallel robots with less than six cables, in crane configuration.
A major challenge in the study of these manipulators is the intrinsic coupling between kinematics and statics, which must be dealt with simultaneously.
A geometrico-static model is provided, together with a general procedure aimed at effectively solving the inverse and direct position problems.
The stability of equilibrium is assessed within the framework of a constrained optimization problem, for which a purely algebraic formulation is provided.
A spatial robot with three cables is studied as an application example
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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