1,721,068 research outputs found
Active and semi-active control of structures: a review of recent advances
No full textThe concepts of active and semi-active structural control in civil and infrastructure engineering date back 40
years. Periodically, state-of-the-art manuscripts have been published and technical books were also printed to testify the
maturation of the topic. This report only covers the last two years of theoretical, numerical and experimental studies, as well as
the use of control algorithms and devices in actual implementations. It is observed that there are still operational limitations to
prevent from the expected growth of the applications in standard design. Some innovative concepts help to foresee future
developments within special sectors of applications
Modeling the Seismic Protection of the Updated Cable-Stayed Bridge Benchmark with Roll-N-Cage Devices
No full textThis work presents and assesses a reduced model of a recently proposed seismic isolation system, namely the Roll-N-Cage one. This system incorporates several interesting features and mechanisms in a single unit; among the others: isolation, energy dissipation, buffering, high vertical stiffness and strength for supporting heavy loads. Departing from previous studies, which were based on the simulation of the Roll-N-Cage device by uncoupled orthogonal unidirectional models, this work first introduces a reduced order coupled bidirectional numerical model of the device. Then the efficiency of such type of control devices, as simulated by the proposed approach, is evaluated for the seismic protection of a cable supported bridge. The bridge model is derived from the ASCE benchmark cable-stayed bridge by mean of an extended version
3D Numerical Characterization Efficiency Assessment of RNC Isolator Experimental Prototypes
No full textThis paper numerically investigates the 3D behavior of a recently proposed seismic isolation system, referred to as roll-in-cage (RNC) isolator, when implanted into a bridge structure. The RNC isolator provides in a single unit all the necessary functions of rigid support, horizontal flexibility and energy dissipation characteristics in addition to and integrated by buffer mechanism. The goal of this study is twofold: first, to examine the main integrated mechanisms of the RNC isolator through sophisticated 3D finite element (FE)
simulation models using a multipurpose FE code. The main result of this step is to attempt modeling force-displacement relationship using the Bouc-Wen model of smooth hysteresis. The second goal of this study is the numerical assessment of the device efficiency through its implementation into a bridge model considering several ground motions as external excitations. Based on these extensive studies, it was found that the RNC isolator is a robust isotropic horizontal isolation device for bridge structures. The force-displacement relationship is satisfactorily predicted by the unidirectional Bouc-Wen model of smooth hysteresis. The buffer mechanism can limit the bearing displacement under severe earthquakes stronger than the design earthquake. The no-uplift mechanism prevents the generation of vertical acceleration components out from the horizontal earthquake components
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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
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