1,720,962 research outputs found
Idealised modelling of estuarine development affected by human interventions and climate change
Get PDFEstuaries worldwide are facing the challenge of coping with changing climates. Insufficient supply of sediment to overcome sea-level rise can increase flood risk and saltwater intrusion and drowning of ecosystems. To explore how estuarine eco-morphology is affected by large-scale human interventions and climate change, an idealised eco-morphological model is developed and validated. The model represents the Nieuwe Waterweg estuary in the Rhine-Meuse Delta. Short-term simulations (1 year) are performed after human-induced changes and projected climate changes are implemented in the model.The model is able to represent annual morphological trends. Results show the sensitivity of the system towards channel depth and the presence and size of wetlands. Simulations will be repeated with projected future climate forcings, enabling assessment of estuarine development after large-scale changes for the present and the future
Evaluation of emerging behaviours on anthropogenic shores with a cellular automata model
Get PDFThis study aims to develop a model to explore the emerging morphological development of anthropogenic shores. We extended an existing Cellular Automata model for the combined development of Dunes, Beaches and Vegetation (DuBeVeg) by including longshore sediment transport and coastline retreat, sand armouring of the beach, and the formation of beach scarps due to wave action. These processes were combined with aeolian, hydrodynamic, groundwater, and vegetation dynamics that were already represented in the model. The extended model was evaluated for a schematized version of the Sand Motor, a mega-nourishment in front of the Dutch coast. The simulated scale and types of dunes compared well with the real dunes that have developed on the Sand Motor since its construction in 2011. These preliminary results show that the extended model can represent the development of mega-nourishments realistically and can be used to assess the goals of such anthropogenic shores for different configurations and scenarios
Bioengineering in front of a river dike:Wave attenuation by vegetation
Get PDFBioengineering is a novel way to reduce the application or dimensions of hard constructions. In the Dutch Noordwaard polder a vegetation field is proposed in front of a planned dike to damp waves such that the desired dike height can be reduced. To investigate the impact of vegetation on waves, the description for wave attenuation as derived by Mendez and Losada (2004) was implemented in the wave model SWAN. The SWAN-VEG model was tested by performing a sensitivity analysis and by calibration and validation on experimental flume data. The model showed expected behavior and calibrated values for the drag coefficient gave reasonable correlations between predicted and measured wave attenuation, except for a plant with flexible floating leaves. Application of the model to the Noordwaard polder showed that a field of willows is able to reduce wave heights by 70% under extreme conditions. This allows a lower dike that fits better into the landscape while maintaining the required safety standard
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
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
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