1,720,983 research outputs found
Assessment of earthquake-induced damage level on buildings: analysis of two different survey methods for a case study
Full text linkPurpose of this paper is to compare different methods for the assessment of earthquake-induced damage on buildings based on survey data, referring to the case study of Castelluccio di Norcia. The seismic events that occurred in Central Italy in 2016 threatened the future of many villages located along the Apennine ridge straddling the Regions of Umbria, Marche, Abruzzo and Lazio: in Castelluccio di Norcia, a minor historical center in the Municipality of Norcia (Umbria), the earthquake occurred on August the 24th caused some damage on localized buildings, but the strongest seismic event – the one occurred on October the 30th and with magnitude Mw 6.5, provoked numerous collapses and widespread failure on several buildings of the village, razing to the ground almost the 60 % of the built heritage. After the two earthquakes respectively, the Fire Brigade organized a reconnaissance campaign and flew over the village via UAVs (Unmanned Aerial Vehicles). By acquiring the videos recorded in this framework, that are currently available on the net and originally not recorded for specific survey purposes, the authors produced 3D models of the village allowing to compare the configuration of Castelluccio in the phases pre- and post- the destructive event of 30th October: in fact, since the level of damage after the earthquake of August the 24th was very low, the model resulting from the video recorded after this earthquake could be used as a model showing the layout of the village before the main struck of October. The result of this study is the Damage Degree Evaluation (DDE) and the following definition of a map showing for each building its class of damage, according to the distinction provided by European Macro-seismic Scale EMS98. On the other hand, another damage level map was studied: the Civil Protection requested, immediately after the earthquake and for the management of disaster response activities, the activation of the COPERNICUS project, providing for the detection of most damaged buildings of the village for an early census of the non-safe areas. The map of the damage level produced within this project is of course more accurate and precise, since it was collected through different acquisition systems: UAV, close-range photogrammetry, LiDAR (Light Detection And Ranging) and SLAM (Simultaneous Location and Mapping)-based mapping. This paper proposes a comparison between the two different DDEs, in order to define whether the first method, even if based on data downloaded via the web and therefore at lower resolution, and even if acquired with a more rapid evaluation procedure not providing for ground-based surveys, can lead to the construction of damage level maps that are plausible and realistic. The question is if the first method of DDE, even if less accurate, can allow to obtain results that are satisfactory and useful in the process of management and monitoring of natural hazards, providing support for the several implied institutions, in terms of information on catastrophes and first disaster rescue management
Propagation of semantic information between orthophoto and 3D replica: a H-BIM system for the north transept of Pisa Cathedral
Full text linkThis contribution proposes a methodological approach for the transfer of annotations between orthophotos and 3D digital heritage models, relying on a mesh-based/point-based representation. The workflow leverages on the exploitation of 2D/3D projective relations and on the identification, propagation, modelling and tiling of virtual models of architectural heritage. Referring to the significant case study of Pisa Cathedral, the method is tested to ensure an informative continuum between 2D medias and 3D representations, in terms of morphology, geometry and semantic enrichment. At first, a high resolution ortho-photo is created to support studies related to conservation and restoration, e.g. to highlight degradation patterns and materials as well as to distinguish cracks, frescoed surfaces, decorations. Then, the information is translated from the 2D support to a virtual 3D mockup: this step is essential to ensure a complete understanding of the architectural heritage object, that can thus be studied in its entirety, considering its morphological complexities. The proposed approach provides a more effective system for the transfer and exchange of semantic information from high-resolution orthophotos to semantically rich 3D models, that can be fundamental even in view of the construction of Heritage-Building Information Modeling (H-BIM) environments
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
Digital Technology and Mechatronic Systems for the Architectural 3D Metric Survey
No full textOver the last decade, we have seen the widespread use of digital survey technologies that have made the three-dimensional (3D) metric survey within reach of all. In the past, lengthy training was needed to use total stations and classical photogrammetry. Today, laser scanning and “new photogrammetry” allow operators with little training to produce 3D models with high spatial density in real time. These systems have therefore made 3D metric survey available to a wide audience of professionals, and have also allowed surveys to be performed with little economic investment in instrumentation. Although this evolution in survey methodologies has certainly brought great benefits, the use of these methods by operators with limited training poses some risk. The proliferation of imprecise processed 3D data, however, constitutes a digital archive of documentation which, by its nature, should be semi-automatically integrated. Issues related to reference systems, scale of representation, accuracy, and related metadata therefore become highly relevant. This paper aims to describe, by means of several case studies, the laser scanner and “new photogrammetry” survey methodologies in light of the aforementioned issues. In addition, the use of “new photogrammetry” in combination with UAV systems will be presented. The integration and miniaturization of positioning systems, attitude measuring systems, and survey instruments (cameras, laser scanners, thermal and multispectral cameras, etc.) allow, by drone flight, the creation of 3D surveys, something that was impossible several years ago without a substantial budget for the use of conventional aircraft
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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