1,720,978 research outputs found
Hydrodynamic and geotechnical controls of scour around offshore monopiles
No full textMarine monopiles can suffer from removal of sediment around their foundations by waves and currents, a process termed scour, which can negatively affect structure stability and integrity of associated infrastructure. Scour is a function of the interaction of local hydrodynamics with the geotechnical properties of the seabed, the feedbacks of which are not well understood. Using the largest prototype scour data base available to date, assembled from field data routinely collected during the consents and design phase of wind farms, this study aims to offer a detailed characterisation of marine monopile scour and conduct critical testing of the current, experimentally-derived, state-of-the-art knowledge and practices. Scour research has been hampered by a dearth of prototype scour observations and much of the existing knowledge is derived from physical and numerical work which has had very little validation with field data. This study addresses the dearth of prototype scour analysis and by adding observations from 281 monopiles more than doubles the size of the currently existing knowledge base on marine monopile scour. Furthermore, the scope, variety and quality of data available in this study have enabled a wider-ranging and more in-depth and problem-focussed analysis of scour to be conducted. The data used in this study comes from a "natural offshore laboratory", consisting of three offshore wind farms in the Outer Thames Estuary, which were strategically chosen to minimise the flow variability within the data set in order to focus on identifying and quantifying the controls on scour exerted by the sea bed substrate. The effect of geotechnical conditions on scour is, so far, little understood as most scour research has focused on unconsolidated sandy sediments. Nevertheless, scour experiments in cohesive substrates have revealed the great complexity of the scour response in such materials. For this reason, quantitatively scrutinizing prototype scour in various substrate types and attempting to establish causal links between geotechnical properties and scour development from real data is important. In order to fulfill the remit of this study, the research is guided by a set of questions, derived from a review of the current scour framework, which pose testable hypotheses and identify knowledge gaps which will be evaluated throughout the course of the analysis. The outcomes of the study include an extensive quantitative description and contextualisation of observed scour with existing prototype observations, a critical validation of current knowledge and methods and an investigation of hydrodynamic and geotechnical controls on scour. Some key findings include improved predictive models for scour depth based on mean water depth as well as secondary relationships for lateral extent and scoured volume. For scour in consolidated and cohesive materials, equations for the estimation of scour-limiting material strength as a function of erosion depth are also proposed. The study concludes with a discussion of temporal, survey resolution and geotechnical issues and recommendations for optimised field data collection and survey strategy, alongside suggestions for additional research to fully resolve some of the findings of this research
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
Numerische Simulation der Schiffswellen-Struktur- Interaktion (NumSiSSI). FuE-Abschlußbericht B3955.01.04.70380
No full textCharacterization of Long-period Ship Wave Loading and Vessel Speed for Risk Assessment for Rock Groyne Designs via Extreme Value Analysis
No full textDuring the last two decades, increasing vessel size in major German estuaries has led to the significant change of the local loading regime i.e. increased importance of ship-induced waves and currents. As a consequence, the intensity of ship-induced loads has increased considerably, resulting in damage to rock structures such as revetments, training walls, and groynes. Research into the causes of rock structure deterioration by the Federal Waterways Engineering and Research Institute (BAW) has shown that for large ships in relatively narrow waterways, the long-period primary ship wave loading has become the most prescient factor for rock structure damage. Looking into the future, it can be expected that the increase in the vessel dimensions will lead to an increase in the ship-wave loading. For this reason, analysing long-term changing trends of long-period ship waves and vessel speed to understand the wave-structure interaction is of significant importance. In this study, the stochastic characterization of long-period primary wave height, drawdown, and speed of the vessel through the water at Juelssand in the Lower Elbe Estuary was analysed via extreme value analysis and copula modeling, and the bivariate return periods were calculated. The one-parameter bivariate copula was utilized to analyse the data. The dependence pattern between the variables was investigated using five parametric copula families: Gaussian, Gumbel, Clayton, Frank, and student's t.Accepted Author ManuscriptHydraulic Structures and Flood Ris
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