1,720,967 research outputs found
Seismic Inversion for Estimating Soil Material Damping for Offshore Wind Turbines
No full textCreating accurate engineering models for predicting the response of large structures often requires geotechnical modelling of soil behaviour. Soil material damping is an important input parameter for modelling the structural response and energy dissipation, especially for embedded and lightly damped structures, as in particular for offshore wind turbines. Non-invasive in-situ measurements like the multichannel analysis of surface waves, offer cost-effective solutions and estimations over a wider volume of soil. This research aims to demonstrate that MASW technique can be used to generate a reliable in-situ estimation of the soil damping in marine environments in the depth range of 0-30m.A unique and high-quality dataset has been made available through a collaboration with the Norwegian Geotechnical Institute (NGI). Shear wave data are rarely available for offshore site investigations and have not been used before for a damping inversion from real surface waves measurements. Moreover, also the horizontal soil response was recorded in this measurements which allow for reducing the uncertainties of the results obtained by using the Scholte wave model. Therefore, two forward waves models are implemented in Matlab to reproduce both the in-line and cross-line measurements.A reliable shear wave velocity profile is derived via the stiffness inversion method, after which the damping inversion is performed. A modal damping inversion method is developed and it uses a novel modified random search algorithm in order to estimate the material damping profile over depth. The attenuation coefficient is chosen as the reference parameter for the damping inversion and the misfit function for the damping inversion is defined as the normalized difference per frequency of the attenuation curves. The measured attenuation coefficient is extracted based on a modified half-power bandwidth method. The modelled attenuation curve is retrieved as the imaginary part of the complex wavenumber. The wavelet compression technique is employed to reduce the number of roots used in the inversion for both the experimental and the theoretical curves. The identification requires solving an inverse problem with a global optimization method. To get a better understanding of the model and computational time, a combination of sensitivity studies, behaviours of the phase damping ratio curves and layer reduction were performed. Then, syntheticinversions are run to verify the validity of the proposed technique. Finally, themethod is applied to the aforementioned collected data and two damping profiles (Scholte and Love models) are computed and they show good agreement in terms of both trend and magnitude.The frequency dependence of the material damping ratio of the soil is analysedfrom the use of measured surface wave data. A novel technique is proposed for retrieving this relation starting from the results of the damping inversion and it shows that the material damping ratio is independent from frequency. Then, two new alternative approaches are proposed, which are based on a simplification of the traditional dependency relation. The first confirms the frequency independence of damping while, although it seems very promising, the second one cannot be tested due to computational limitations. The demonstrated frequency independence of the material damping is only valid based on the frequency ranges available in the dataset and cannot be generalized to cover all scenarios
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Distributed Nonlinear AIMD Algorithms for Electric Bus Charging Plants
Full text linkRecently, the introduction of electric vehicles has given rise to a new paradigm in the transportation field, spurring the public transport service in the direction of using completely electric bus fleets. In this context, one of the main challenges is that of guaranteeing an optimal scheduling of the charging process, while reducing the power supply requested from the main grid, and improving the efficiency of the resource allocation. Therefore, in this paper, a power allocation strategy is proposed in order to optimize the charging of electric bus fleets, while fulfilling the limitation imposed on the maximum available power, as well as ensuring limited charging times. Specifically, relying on real bus charging scenarios, a charging optimization algorithm based on a Nonlinear Additive Increase Multiplicative Decrease (NAIMD) strategy is proposed and discussed. This approach is designed on the basis of real charging power curves related to the batteries of the considered vehicles. Moreover, the adopted NAIMD algorithm allows us to minimize the sum of charging times in the presence of saturation constraints in a distributed way and with a small amount of aggregated data sent over the communication network. Finally, an extensive simulation campaign is illustrated, showing the effectiveness of the proposed approach both in allocating the power resources and in sizing the maximum power capacity of charging plants in progress
- …
