1,720,979 research outputs found
A damage detection strategy on bridge external tendons through long-time monitoring
No full textIn recent years, Structural Health Monitoring (SHM) has gained a lot of attention, given the need to detect a structure damage at an early stage. A series of technological advances, especially in the world of new sensors, has allowed more structures to be equipped with an always increasing number of monitoring systems of different nature. The state of the art of monitoring systems involves the interaction and cooperation of elements such as low-cost sensors, efficient communication networks, data transfer and storage, often based on cloud architectures. If on the one hand the amount of data collected by the new SHM systems tends to be of considerable size, the search for damage passes through a process of information synthesis aimed at defining features able to describe the health of the monitored structure. Although many papers in literature are focused on the definition of an early warning through the most suitable damage feature, less attention has been paid till now to the challenge of implementing a fully automatic monitoring system that can serve as a robust and reliable tool for decision making. This paper presents a framework/architecture for a real-time data elaboration process, based on different alarm levels to track an ongoing and growing damage. Into details, data coming from a large number of MEMS accelerometers, installed on tensioning cables inside a box composite highway bridge, are continuously processed and analyzed at the sensor level. This is done on a microcontroller equipping each sensor, thanks to both fit-to-the-purpose algorithms that do not require huge computational effort and a strategy which can manage each sensor independently from the others. At a first stage, the proposed strategy is able to identify every kind of anomalies in the collected data; then, the benign phenomena, such as the occurrence of heavy though not extraordinary loading conditions, are identified and separated from those which clearly point at a damage, such as the breaking of the strands of prestressed cables. As these events occurred during the monitoring and have been recorded, we have a check about the capability of the chosen algorithms to perform this clustering. Different output examples are discussed in this paper in order to provide a significant case study where the effectiveness of a SHM system is discussed in a damage detection perspective
Comparison of different SMA-based adaptive tuned mass dampers
Full text linkThe use of smart materials has proven to be an effective strategy in the development of Adaptive Tuned Mass Dampers (ATMD). Among different possible materials, Shape Memory Alloys (SMA) show specific features which make their use advantageous for building ATMDs. More in detail, by heating/cooling the SMA components, it is possible to change the natrural frequency of the ATMD, thus allowing maintaining the ATMD tuned on the primary system to be damped. The heating/cooling is obtained by changing the amount of electrical current flowing through the SMA elements and, consequently, the amount of heat produced through Joule’s effect. This paper compares the two main layouts for designing ATMDs based on SMAs in case the primary system to be damped is excited by a disturbance of random nature: cantilever beams and tensioned wires with a central mass. The two layouts, which can be described through detailed and experimentally validated models, are compared in terms of adaptation capability, exerted force and electrical power consumption. It results that the wire-based layout, despite being characterised by a more complicated set-up, is less demanding in terms of power consumption and shows much better adaptation capability
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
Refractory Spasm of Coronary Arteries and Grafted Conduits After Isolated Coronary Artery Bypass Surgery
No full textLongitudinal strain predicts left ventricular mass regression after aortic valve replacement for severe aortic stenosis and preserved left ventricular function.
No full textDispelling 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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