1,720,986 research outputs found
Consideration of interstory drift profile in selection and scaling of ground motion records
No full textInterstory drift based scaling of earthquake ground motions
Full text linkA novel amplitude scaling procedure is proposed in this study where the ground motion scaling factors are defined as the ratio of interstory drift distributions under target spectrum versus under the associated ground motion spectrum. The advantage of employing interstory drift ratio in ground motion scaling, compared to employing spectral intensity directly, is that it provides a strong theoretical link between the target spectrum intensity and the fundamental dynamic characteristics of the structure. Hence, scaling is conditioned on structural response, which is in turn a function of seismic intensity. The interstory drift-based scaling procedure (IDS) is presented herein for planar frames for brevity. Accuracy and efficiency of the IDS procedure is assessed under a set of near fault strong motions from large magnitude events. The results revealed that the proposed procedure is accurate since the resulting bias in estimating linear elastic interstory drifts is negligibly small. Further, it is noticeably more effective as compared to the conventional procedures suggested in recent seismic codes, yet it is simpler
Interstory drift based scaling of bi-directional ground motions
No full textThe interstory drift-based scaling procedure (IDS) developed recently by the authors for plane frames under single component horizontal ground motions, has been extended to three-dimensional structures possessing torsional coupling under bi-axial ground motions which are represented by their geometric mean spectrum. The ground motion-scaling factor is defined as the ratio of average interstory drift along building height under target spectrum versus that under the associated ground motion spectrum. Hence, scaling is conditioned on structural response, which is in turn a function of seismic intensity. IDS for 3D systems is applied to 20-story and 3-story concrete space frames with mass and stiffness eccentricity, respectively. Accuracy and efficiency of the IDS procedure is assessed under a set of near-fault strong motion pairs from large magnitude events. The results revealed that the proposed procedure is accurate and noticeably more efficient as compared to conventional procedures suggested in seismic codes and in literature. Further, the intensity measure employed in the IDS procedure is proved as a good predictor of fundamental demand measures (maximum interstory drift ratio and maximum plastic rotations) obtained from nonlinear dynamic analyses under individual ground motion pairs. Hence, employing the intensity measure of IDS for ground motion scaling in intensity-based evaluation of structures is proposed for reliable estimation of structural performance under code-prescribed seismic hazard
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
Experimental investigation of the behavior of variable friction base isolation systems
No full textThis paper describes a preliminary experimental study aimed at investigating the force-displacement behavior of Variable Friction base isolation Systems (VFSs). Full-scale VFS prototypes were tested under cyclic loading conditions. A series of dynamic hybrid tests simulating the response of a full-scale single-story structure isolated with VFS devices and subjected to ground motions with different intensities, was also performed. The results of the experiments are presented and used to provide some preliminary validation of a previously developed numerical model. Overall, the results of the experiments were in good agreement with the predictions provided by the numerical analyses
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
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
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