1,720,983 research outputs found
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
Life cycle cost analysis of low ductility r.c. frame buildings retrofitted by modern retrofit techniques
Full text linkMany reinforced concrete (RC) frame buildings designed before the introduction of modern seismic codes are highly vulnerable to seismic actions due to their reduced ductility capacity. Passive control systems have emerged to be efficient tools for the seismic retrofit of low ductility RC frames and help to reduce economical losses in consequence of seismic events. Since funds to investment for seismic vulnerability reduction may be limited, a risk-based life cycle cost analysis approach is required to evaluate and compare the cost effectiveness of different mitigation strategies. In this paper, several retrofit methods are compared. In particular, superelastic Shape Memory Alloys braces or Buckling Restrained Braces are investigated for
their effectiveness in reducing seismic vulnerability and losses. A benchmark two-dimensional reinforced concrete frame with low ductility capacity is considered as a case study. The frame is designed for gravityload only and does not comply with modern seismic code requirements. The retrofit devices are designed in
a way to obtain the same base shear capacity for the two retrofitted frames. The study to evaluate the effectiveness of the retrofit is conducted by a probabilistic approach where the seismic record-to-record variability is modeled by using a suite of recorded ground motions, and nonlinear time history analyses are
performed to generate samples of the demand. Fragility curves are generated for slight, moderate, extensive and collapse limit states. Finally, the comparison among the different retrofit methods is conducted by performing a Seismic Life Cycle Cost Analysis and by evaluating the loss saving for each method
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
Component-based Probabilistic Methodology for the Vulnerability Assessment of RC Frames Retrofitted with Dissipative Braces
Full text linkThe paper illustrates a probabilistic methodology for assessing the vulnerability of low-ductility reinforced concrete (RC) buildings retrofitted by dissipative braces. The aim is to highlight the most important parameters controlling the capacity of these systems and specific aspects concerning the response uncertainties. The proposed methodology is based on local engineering demand parameters (EDPs) for monitoring the seismic response and on the development of component and system fragility curves before and after the retrofit. Its capability is tested considering a RC frame designed for gravity-loads only retrofitted by elasto-plastic dissipative braces. The results show the effectiveness of the methodology in describing the changes in the response and in the failure modalities due to the retrofit. Moreover, the retrofit effectiveness is evaluated by introducing proper synthetic parameters describing the fragility curves and highlighting the importance of employing local rather than global EDPs in the seismic risk evaluation of low-ductility frames
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
Local and Global Response Parameters in Seismic Risk Assessment of RC Frames Retrofitted by BRBs
Full text linkThis paper deals with the seismic performance and risk assessment of existing reinforced concrete (RC) buildings with limited ductility retrofitted by means of buckling restrained braces (BRBs). Two different approaches for evaluating the seismic vulnerability and risk before and after retrofit are introduced and analyzed. These approaches involve the use of different categories of engineering demand parameters (EDPs) for the system response assessment: global EDPs, that permit to obtain a synthetic description of the system behavior at a reduced computational cost, and local EDPs, more accurate in describing the response of the frame elements and of the BRBs, though more demanding from a computational point of view.
A probabilistic methodology is first introduced that permits to evaluate and compare the vulnerabilities of the frame before and after the retrofit (Freddi et al. 2012). This methodology, similarly to other methodologies present in the literature (e.g., Hueste and Bai 2006, Ramamoorthy et al. 2006, Özel and Güneyisi 2012), is based on the development of system fragility curves before and after the retrofit. However, differently from the others, it employs local rather than global EDPs to monitor the structural seismic response. This approach allows to capture accurately the modifications of the frame components’ response induced by the added bracing system. Successively, the effects of the EDPs choice on the seismic risk assessment and risk-based design of the retrofit of existing RC frames with dissipative braces is investigated by considering and analyzing a specific case study. This consists of an existing RC frame with low ductility capacity retrofitted by inserting a system of BRBs with elasto-plastic behaviour. The braces are designed by applying a widespread method based on an equivalent nonlinear SDOF approximation (Dall'Asta et al. 2009) and by considering different values of the shear capacity of the bracing system.
The importance of using local EDPs in the probabilistic evaluation of the retrofit effectiveness for the type of system analyzed in this paper is demonstrated by comparing both the fragility curves and the risk estimates under different hazard scenarios. It is shown that the use of global EDPs may result in a significant overestimation of the retrofit effectiveness in terms of both vulnerability and risk reduction. Consequently, if a risk-based design is carried out for the retrofit system, the dimension of the braces evaluated by using global EDPs for vulnerability assessment are significantly lower with respect to the corresponding dimensions obtained by using local EDPs. Larger differences are observed for the hazard scenarios with higher intensity
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