1,720,971 research outputs found
NUMERICAL AND EXPERIMENTAL INVESTIGATION ON THE WAVE-WAVE INTERACTION IN BREAKING AND NON-BREAKING FOCUSING WAVES
Full text linkThe modelling of large individual waves for the computation of loads on ships and offshore structures in
extreme weather conditions is still a challenging problem. Since the early 50s the predictions of loads on
fixed offshore structures and motions of compliant or sailing structures due to surface waves are
commonly made by computations on the basis of the statistical/spectral description of the sea elevation
and of a linearized response model. Quadratic Transfer Functions or fully non-linear methods are used
only in specific cases. The linear approach is recognized to work reasonably well for the so-called
operational conditions, assuming that hydrodynamic and dynamic nonlinear effects can be neglected. On
the other hand, it is also recognized that the modelling of large amplitude motions and the modelling of
waves in the so-called survival conditions, i.e. extreme wave conditions, cannot recast a linear approach.
In these conditions the wave-wave interaction plays a fundamental role (energy transfer, down-shift, etc) in
the actual deterministic or spectral representation of the wave/flow field and thus in the related loads on
the structure.
In the present paper the nonlinear aspects related to the behavior of steep focusing breaking and non-
breaking waves are analyzed by means of numerical simulations and new experiments. The experiments
are carried out at the wave flume of the Laboratory of Maritime Engineering (LABIMA) of the Dept. of Civil
and Environmental Engineering of the University of Florence. The computations are carried out at
Hydrodynamic and MetOcean Laboratory (HyMOLab) of the Dept. of Engineering and Architecture of the
University of Trieste. The paper focuses the attention on the comparison between the results obtained with
a state-of-art viscous flow simulation and laboratory experiments, with particular emphasis on the spectral
energy exchange between component waves of a non-breaking and breaking focusing wave train. This
study is carried out as part of the research project “OpenViewSHIP Development of an integrated
computational ecosystem for the hydrodynamic design of the hull-propeller system”, co-financed by Friuli
Venezia Giulia Region in the field of industrial application of open-source CFD and High Performance
Computing
MWM: A 35 years wind&wave high resolution hindcast dataset and an operational forecast service for the mediterranean sea
No full textThe use of reliable wind and wave data for the planning of operational activities at sea is considered of primary importance. This regards the coastal engineering, the oil&gas and recoverable energy fields, the civil protection, the design of offshore structures and ships, the planning of operations at sea and so on. DHI and HyMOLab (Hydrodynamics and Met-Ocean Laboratory of the Dept. of Engineering and Architecture of the University of Trieste) have undertaken a joint research project with the aim to develop a state-of-art wind-wave hindcast dataset for the Mediterranean Sea. The dataset consists of 35 years of hourly data for the period 1979-2013, obtained from a last-generation model chain. The meteorological model used is WRF-ARW, one of the most widely used state-of-the-art open-source non-hydrostatic model. The CFSR d093.0 hourly dataset with a spatial resolution of 0.5° provides the boundary and initial conditions. MIKE21 is used as the wave model with resolution ranging from 0.1° to 0.03° approximately. The use of a local area meteorological model guarantees higher levels of resolution and accuracy in an area such as the Mediterranean Sea where the complex orography and coastline induce short-time/smallspace weather scales. The atmospheric and wave models performance is checked against seven satellite datasets, missions Envisat, ERS-2, Geosat FO, Jason-1, Jason-2, Topex-Poseidon and CryoSat, by means of a procedure based on the moving window technique. Wave data close to coast are compared with available data from more than 20 buoys. The validation performed at the time of the preparation of this manuscript involves ten years of data (2002-2011) and is based on the significant wave height parameter. The results are summarized in probability scatter plots, which show a very good accuracy of the model for both the comparisons with satellite and fixed buoys. Taking advantage of the model set-up performed for hindcast purposes and verified with measured data, an operational wind-wave forecast service has been developed and put to use. The forecast service uses the GFS dataset to provide the boundary and initial conditions
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
A high resolution wind&wave forecast model chain for the Mediterranean and Adriatic Sea
Full text linkDHI (Danish Hydraulic Institute) and HyMOLab (Hydrodynamics and Met-Ocean Laboratory of the Dept. of Engineering and Architecture of the University of Trieste) have undertaken a joint applied research project with the aim to develop a state-of-art wind-wave forecast service at mid resolution for the Mediterranean Sea and at very high resolution for the Adriatic Sea. Weather routing, civil protection, coastal engineering, oil&gas and renewable energy fields, the planning of operations at sea, ... are just few among the multiple potential applications of this service. The meteorological model used in this study is WRF-ARW, one of the most widely used state-of-the-art open-source non-hydrostatic model. Global Forecast System (GFS) dataset
provides the boundary and initial conditions. MIKE21-Spectral Waves is used as wave model with resolution ranging from 0.1 to 0.03 approximately. The use of a local area meteorological model guarantees higher levels of resolution and accuracy in an area such as the Mediterranean Sea where the complex orography and coastline induce short-time/small-space weather scales. The model chain runs daily (or twice a day on demand)
on the High Performance Computing (HPC) infrastructure of HyMOLab. The validation of the entire model chain and specifically the forecast data obtained for the sea state is continuously updated according to new available data from satellites and buoys. Anyway, a major verification of the performance of the model chain against historic data (hindcast) is almost mandatory. For this aim, we performed a multi-decade test obtaining
very good statistical parameters for the entire model chain performance. In this context the hindcast dataset developed by DHI and HyMOLab consists of 35 years of hourly data for the period 1979-2013, with the same model chain. The CFSR d093.0 hourly dataset with a spatial resolution of 0.5 provides the boundary and initial conditions. The atmospheric and wave models performance is checked against six satellite datasets, missions
Envisat, ERS-2, Geosat FO, Jason-1, Jason-2, Topex-Poseidon, using a moving window technique procedure.
Wave data close to coast are compared with available data from more than 20 buoys. The paper describes the validation procedure adopted for the hindcasted data. Furthermore the forecast service is described too, with specific emphasis to the very high resolution adopted in the Adriatic Sea
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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