1,720,965 research outputs found
Seismic vulnerability assessment of New Zealand unreinforced masonry churches
Full text linkChurches are an important part of the New Zealand historical and architectural heritage, and the extensive damage occurred to stone and clay-brick unreinforced masonry portfolio after the 2010-2011 Canterbury earthquakes emphasises the necessity to better understand this structural type. An effort was undertaken to identify the national stock of unreinforced masonry churches and to interpret the damage observed in the area affected by the earthquakes: of 309 religious buildings recognized and surveyed nationwide, a sample of 80 churches belonging to the Canterbury region is studied and their performance analysed statistically. Structural behaviour is described in terms of mechanisms affecting the so-called macro-elements, and discrete local damage levels are correlated firstly with macroseismic intensity through Damage Probability Matrices, computed for the whole building and for each mechanism. The results show that the severity of shaking alone is not capable to fully explain the damage, strongly influenced by structural details that can worsen the seismic performance or improve it through earthquake-resistant elements. Simple-linear regressions, correlating the mean damage of each mechanism with the macroseismic intensity, but neglecting the difference in the vulnerability of different churches subjected to the same level of shaking, are then improved through use of multiple-linear regressions accounting for vulnerability modifiers. Several statistical procedures are considered in order to select the best regression equation and to assess which parameters have closer relationships with damage. Results show good consistency between observed and expected damage, and the proposed regression models can be used as predictive tools to help determine appropriate seismic retrofit measure to be taken. The conclusions drawn for the Canterbury region are then extended to the whole national stock and a quantitative seismic risk assessment for existing unreinforced masonry churches in New Zealand is presented, using different intensity measures to model the seismic hazard. Seismic risk is first computed mechanism by mechanism, highlighting how some mechanisms are more frequent than others, and that very large damage levels are expected for some New Zealand regions. Whereupon, an alternative synthetic damage index purely based on observed data is proposed to summarise damage related to several mechanisms and it is used to validate the choice of the best index for describing the global damage of a church when dealing with a territorial assessment. Territorial scale assessment of the seismic vulnerability of churches can assist emergency management efforts and facilitate the identification of priorities for more in-depth analysis of individual buildings. Finally, a preliminary attempt for dynamically characterize the response of unreinforced masonry church is conducted
Estimation of clay-brick unreinforced masonry compressive strength based on mortar and unit mechanical parameters
No full textVulnerability Assessment of Unreinforced Masonry Churches Following the 2010–2011 Canterbury Earthquake Sequence
No full textThe 2010–2011 Canterbury, New Zealand earthquake sequence caused extensive damage to unreinforced masonry churches. A sample of 80 affected buildings was analysed and their performance statistically interpreted. Structural behaviour is described in terms of mechanisms affecting the so-called macro-elements, and damage probability matrices are computed. Regression models correlating mean damage level against macroseismic intensity are also developed for all observed mechanisms, improving the initial simple-linear formulations through use of multiple-linear regressions accounting for vulnerability modifiers, whose influence is evaluated via statistical procedures. Results presented herein will support the future development of predictive tools for decision-makers, also contributing to seismic vulnerability mitigation at a territorial scale
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
Seismic Risk Assessment of New Zealand Unreinforced Masonry Churches using Statistical Procedures
No full textThe 2010–2011 Canterbury earthquake sequence provided extensive evidence of the significant seismic vulnerability of New Zealand unreinforced masonry (URM) churches. Given the high seismicity of the country, the exposure of human lives and the societal significance of ecclesiastic buildings, for both historical and religious reasons, the reduction in seismic vulnerability of this building type is of primary importance. By analyzing the seismic performance of a sample of 80 affected buildings, regression models correlating mean damage levels against ground-motion parameters were developed for observed collapse mechanisms, accounting for vulnerability modifiers whose influence was estimated via statistical procedures. Considering the homogeneity of New Zealand URM churches, the vulnerability models developed for the Canterbury region were extended to the whole country inventory, and a synthetic index was proposed to summarise damage related to several mechanisms. Territorial scale assessment of the seismic vulnerability of churches can assist emergency management efforts and facilitate the identification of priorities for more in-depth analysis of individual buildings. After proper calibration, the proposed approach can be applied to other countries with similar building heritage
Statistical seismic vulnerability of New Zealand unreinforced masonry churches
No full textDuring the 2010–2011 Canterbury earthquake sequence, extensive damage occurred to NewZealand historical and architectural heritage, and particularly to unreinforced stone and clay brick masonrychurches. Of 309 unreinforced masonry churches identified nationwide, a sample of 80 buildings belonging tothe affected region was studied and their performance analysed statistically. Structural behaviour of religiousbuildings was described in terms of mechanisms affecting the so-called macro-elements, being portions of thebuilding behaving more or less independently. Discrete local damage levels were correlated with macroseis-mic shaking intensity through Damage Probability Matrices. Multiple-linear regressions were also considered,accounting for additional modifiers increasing/reducing the vulnerability of the macro-elements. Results showthe relevance of the proposed multiple-linear regression models for the national heritage of churches and theadvisability of extending mechanism-based regressions to other countries besides New Zealan
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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