1,721,068 research outputs found
Experimental and analytical investigation on the lateral response of ball rubber bearing isolators
No full textRecent earthquakes demonstrated that modern seismic design and retrofit of constructions should target damage containment to reduce the direct and indirect economic losses and downtime. In this context, the use of base isolation as seismic protection strategy is becoming popular. A variety of devices is available on the market. Elastomeric and metallic sliding devices are the most common type of isolators. Ball rubber bearings (BRBs) combine the practical use and the low maintenance cost of elastomeric bearings with a friction-based dissipation due to the steel balls of the inner core. Although many tests were performed to characterize the lateral response of BRBs, their stiffness, the maximum displacement capacity and the damping, further studies are needed to clearly identify the main variables and their effects on the lateral response. This research paper aims at developing a design-oriented formulation to estimate the equivalent damping, the characteristic strength and the lateral stiffness of BRBs. In order to calibrate and validate the proposed formulation, experimental tests are performed varying the axial load pressure and maximum imposed displacement. Furthermore, all the tests available in literature are collected in a unique database. Simple considerations on the influence of the different design parameters are discussed and used to calibrate reliable design formulations to be used in the design practice
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Creep effects on elastomeric and ball rubber bearings under sustained lateral loads
No full textBase isolation applications are becoming popular in the seismic design of resilient structures and infrastructures. Even though the response of the bearings is widely studied under cyclic displacements, limited information is available for bearing response under sustained lateral loads. These types of loads can develop sustained lateral displacement in the bearing. During the holding time under sustained lateral displacement, the creep or stress relaxation may significantly change the properties of the bearings and may affect the response in the reloading stage. This research paper aims at assessing the influence of short-term lateral creep on the hysteretic response of rubber bearings, and ball rubber bearings. To this end, experimental testing on different elastomeric bearings under imposed lateral displacement is performed. For each device, the lateral response is measured, and the advantages and disadvantages are discussed in terms of strength, stiffness, energy dissipation and equivalent damping. The loss of load under sustained lateral displacement is experimentally assessed and the effects of creep in the design procedure of a base isolated system are discussed
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
DERİN ÖĞRENME VE BİLGİSAYAR GÖRÜŞÜ KULLANARAK YAPI ELEMANLARINDA PASLANMA ORANLARI TESPİTİ
No full textVisual inspection conducted by inspectors has a great role in today’s structural evaluations. However, evaluations may differ through inspectors. Thus, to standardize the assessment of corrosion, this research tried to create a tool for site engineers. Basically, deep learning models were trained with new datasets of 1198 and 536 images, for corrosion and structural member instance segmentations. The outcomes were post-processed to increase the performance of the system. Detected member and corrosion instances were matched and corrosion percentages of structural members were calculated. The results were evaluated in terms of detected corrosion, member mask accuracy and the calculated cover percentage. In the end, overall accuracy was obtained as 52.3 % where averages of mIoU for corrosion, member segmentation and calculated cover percentage accuracy is equal to 67.4%, 93.4% and 82.9% accordingly. This research shows the possible usage of AI- powered tools for site engineers in corrosion rate detection where it is offered to public use with a website called “corrosionrate.org”.Günümüzde denetmenler tarafından gerçekleştirilen görsel yapı değerlendirmelerinin büyük bir rolü bulunmaktadır. Fakat, denetçilerin farklı bakış açılarına ve inisiyatiflere sahip olmaları değerlendirmelerde çok fikirliliğe ve tutarsızlığa sebep olabilmektedir. Bu nedenle, korozyon değerlendirmesini standartlaştırmak amacıyla bu araştırmada saha mühendisleri için bir araç oluşturulmaya çalışılmıştır. Temel olarak, 1198 ve 536 görüntüden oluşan veri kümeleriyle, korozyon ve yapısal eleman örnek segmentasyonu için derin öğrenme modelleri eğitilmiştir. Modellerden elde edilen sonuçlar, sistem performansını artırmak amacıyla ilave işlemlerden geçirilmiştir. Tespit edilen eleman ve korozyon örnekleri eşleştirilmiş ve yapı elemanlarının korozyon yüzdeleri hesaplanmıştır. Sonuçlar, hesaplanan yüzde, tespit edilen korozyon ve üye maskesi doğruluğu açısından değerlendirilmiştir. Sonunda, pas, eleman tespiti ve pas yüzdeliği hesabı başarı oranları %67,4, %93,4 ve %82,9 olarak bulunmuş ve genel başarı oranı %52,3 olarak hesaplanmıştır. Bu araştırma, yapay zekâ destekli bir aracın saha mühendisleri için korozyon miktarı tespitinde olası kullanımını göstermiştir. Bu araç “corrosionrate.org” web sitesinde halka açık kullanıma sunulmuştur.M.S. - Master of Scienc
Gergin eğik askılı köprüler için hareketli yük tasarım parametrelerinin TürkLRFD methodu için belirlenmesi.
No full textIn Turkey, bridge design procedure has been followed from a modified version of the AASHTO LFD (Load Factor Design) or ASD (Allowable Stress Design) requirements until now. The recent switch of the US bridge codes to LRFD method also necessitates the calibration of the new design of the Turkish bridges according to the LRFD system. The main aim of this study is to develop the load and resistance factors to be implemented in the design of steel composite I-girders of cable-stayed bridges (span lengths 420 m to 550 m) for the basic gravity load combination. Moreover, the performance of new type of live (truck) load of Turkish LRFD, namely, AYK-45 is evaluated. In such studies, usually a target reliability index is selected to reflect the safety level of current design practice based on the uncertainties associated with the design parameters. For the basic gravity load combination, which includes the dead and live loads, a minimum target reliability of 4.30 is selected, instead of 3.50 that have been used in US. In the statistical computations of the reliability index, the quantification of uncertainties is made based on local data supplemented by information compiled from relevant international literature.M.S. - Master of Scienc
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