1,722,411 research outputs found
Innovative mechanical sensors architectures and their physics applications
No full textVibrations measurement is relevant in many applications, since the acquired signals contain direct and indirect information on the dynamic behavior and on the health state of systems, in connection to external forcing. Although generally spread over a large band, the low-frequency signal content (1 mHz–10 Hz), the so-called slow-motion, contains the most relevant part of information, as in the case of large structures, like buildings or bridges, subject to environmental and anthropic forcing. For this reason, despite the large present scientific and technological research efforts aiming at implementing suitable typologies of sensors, the low-frequency band is still only partially covered by sensors, due to the difficulty of satisfying the stringent requirements on their mechanical oscillators, like low resonance frequency, high directivity and low intrinsic noise. The Folded Pendulum, a classical mechanical oscillator, whose monolithic architecture has been reinvented for the design of low-frequency mechanical oscillators, may represent an interesting solution. In this work, we present and discuss theoretical properties and experimental applications of the Folded Pendulum mechanical oscillator, highlighting its peculiar characteristic for its use as an instrument for low-frequency measurements
Mechanical Monolithic Inertial Sensors for Historical and Archeological Heritage Real-Time Broadband Monitoring
No full textThe evaluation of the health state of historical and archeological infrastructures requires an analysis of their dynamical behavior in connection with natural and anthropic actions, whose accuracy is mainly determined by the band and sensitivity of the sensors. The latter are generally accelerometers, consisting of classical mechanical oscillators with a force feedback control, whose improvement has been directed and determined by the progress of the control electronics in the last decades. The mechanics, instead, has experienced only a limited evolution, mainly due to the introduction of new materials and modern machining techniques. But recently the introduction of the UNISA folded pendulum technological platform, a synthesis of more than 10 years of research and development, is allowing the implementation of very low-frequency compact monolithic oscillators (<100 mHz), limited in sensitivity only by their mechanical thermal noise (<10−14m/sqrt(Hz),making it possible the implementation of state-of-the-art inertial seismometers, accelerometers, and tiltmeters. Many different mechanical sensors based on this platform have been tested along the years, with relevant scientific results and applications also in the field of historical and archeological heritage, like the Trajan Arch in Benevento (Italy). In the following, models, implementations, and selected scientific results are presented and discussed
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
Adaptive Modular Monitoring Systems as Interfaces with Finite Element Models in the “Phygital” Dynamic Evolution of Historical Monuments
No full textThe preservation of cultural heritage structures demands a multidisciplinary approach to gather essential information for guiding maintenance, protection, and restoration efforts, with the goal of preserving their aesthetic, historical, and functional integrity. In this context, understanding the structure dynamic behavior and predicting the potential structural changes over time is crucial for assessing its overall structural health. Achieving this result requires an integrated process, combining dynamic numerical modeling and distributed modular measurements within a single adaptive optimization framework. This comprehensive synthesis is now feasible through a dynamic finite element model (DFEM) mutual optimization procedure, that we previously introduced in the literature. This procedure, integrating a digital model with a physical monitoring counterpart into a self-updating hybrid ‘phygital’ system, reframes the role of the monitoring system from an ancillary position to an essential component of the system, due to the need of detecting the degree of freedom of the structure, which, from one side, are needed to tune the dynamic model, and, on the other side, might be variable, depending not only on external excitatory sources, but also on the non-homogeneity of the structure, as well as on its degradation along time. With this respect, the key features of the monitoring solution, that has been already applied in integration with the DFEM procedure in the context of cultural heritage, are discussed through a past case study, referred to the ancient Roman bridge (2nd century BC) over the Savuto River, found between the municipalities of Scigliano and Altilia (Calabria Region, Italy)
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
Dall’“Elogio della profanazione” alla paura della violazione del sepolcro: per una rilettura delle mani alzate sui sepolcri di epoca romana
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