1,720,962 research outputs found
Assessment of low-rise buildings with transfer beam under seismic forces
No full textAn overview of the structural performance of a transfer structure in Hong Kong under potential seismic actions is presented. A hypothetical but realistic low-rise building model has been developed comprising a seven-storey reinforced concrete frame structure with reinforced concrete transfer beams at first floor level. Structural design has been based on the British Standard BS8110 and local practices. Parametric analyses of the moment–curvature relationship of each component have been conducted. By adopting the displacement-based (DB) approach, various seismic assessment methodologies, including response spectrum analysis (RSA), manual calculation, pushover analysis (POA) and equivalent static analysis (ESA) have been implemented. The deformations induced by the predicted seismic actions in Hong Kong are compared with those arising from POA in terms of average lateral drift ratios and maximum interstorey drift ratios arising in the building. Factors influencing the performance of this form of transfer structure are highlighted and discussed. This paper also provides a general indication of seismic vulnerability of common low-rise transfer structures in regions of low to moderate seismicity
Simplified inverse dynamics models for MR fluid dampers
Full text linkThe magnetorheological (MR) damper is considered to be one of the most promising semi-active control devices for reduction of structural vibration. Due to the damper’s nonlinear characteristics, its inverse dynamics model is difficult to obtain. In this paper, a simplified approach, namely the simplified inverse dynamics (SID) model, has been developed for both the Bingham plasticity model and the Bouc–Wen hysteresis model. SID models have then been used to calculate the optimal fluid yield stress or input current, in order to realize the desirable control forces obtained from various optimal control algorithms. For each model, a piston velocity feedback (PVF) algorithm and a damper force feedback (DFF) algorithm have been formulated. The proposed model has been shown to be applicable to both small-scale and large-scale MR dampers. Also, different configurations of MR dampers, such as ones with different dimensions, coil resistances, types of MR fluid, have been employed to show the generic nature of the SID model. The effectiveness of force tracking using the SID model has been demonstrated through a series of numerical simulations. A multi-storey frame structure with MR damper–brace systems, using a large-scale 20-ton MR damper, has been adopted. Numerical results show that the MR damper with the proposed SID model can produce forces very close to the optimal control forces, and that the response reduction is very close to that for the case of fully active control. Also, equally high accuracy of force tracking for different shaking levels and frequency contents of ground motions can be observed. The results demonstrate that the SID model can be a simple, yet effective, tool for both research and application purposes
Influence of non-structural components on lateral stiffness of tall buildings
Full text linkA building is a complex assemblage of both structural and non-structural components (NSC). Although many NSC, such as partition walls, external walls, parapet walls, stairwells, elevator shafts and so forth, are connected directly to the structural system, their behaviour and stiffening effects under lateral loading have normally been ignored by design engineers, despite significant advances in computer technology and the availability of modern computational resources. The performance of structures can be greatly improved by the increase in strength arising from the NSC; on the contrary, this increase in strength also accompanies an increase in the initial stiffness of the structure, which may consequently attract additional seismically induced lateral inertia forces. This paper is concerned with the estimation of the lateral stiffness contributed by the NSC to the total stiffness of three common forms of tall building structures constructed in Hong Kong. Both dynamic tests and numerical modelling of the buildings have been carried out for this purpose. Natural period estimates from dynamic tests and from analyses using calibrated finite element models were found to be in remarkable agreement. Significant stiffness contributions from NSC to the total lateral stiffness of tall buildings have been observed in the study. The extent of the contributions depends on the structural form and the type of components. Other contributions to the additional stiffness have also been analysed for comparison in the study
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
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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