1,720,979 research outputs found
Propagation of discharge uncertainty in a flood damage model for the Meuse river
Get PDFUncertainty analysis plays an important role in the decision- making process. It can give decision makers a complete idea of how different measures will affect the whole river system. Thus it helps decision makers to make a better choice among measures in a more systematic manner. In case of flood damage reduction projects, uncertainty analysis helps to evaluate the main decision criterion – expected annual damage. The aim of this paper is to investigate the propagation of discharge uncertainty, which is one of the main uncertainty sources in a damage model, into expected annual damage. The discharge uncertainty considered here includes model uncertainty (choice of different probability distributions) and sampling errors due to finite gauge record lengths. The calculated uncertainty in the discharge varies between 17 percent for a return period of 5 year and 30 percent for a return period of 1250 year. A first order method is used here to explore the role of discharge uncertainty in the expected annual damage model. The results from the damage model indicate that both model uncertainty and sampling errors are important, with the latter being somewhat more important. The Log-Pearson Type 3 gives a much smaller uncertainty range of the expected annual damage than the other three distribution models used. The uncertainty is aggravated when propagated into the damage results. The uncertainty in the damage reduces a great amount when the sample size increases to n=80. The results derived from the first order method in fact give two bounds of uncertainty, which is an overestimate in this case
The Influence of Floodplain Compartmentalization on Flood Risk Within the Rhine-Meuse Delta
Get PDFThe present compartmentalization layout within the river polders in the Dutch Rhine-Meuse delta is the result of abandonment and partially removal of secondary dikes and the construction of modern infrastructure embankments. These structures will guide the flow of water in case the polder would inundate. Through the application of a 2D flood propagation model in the polder "Land van Maas en Waal" this study explores whether restoration or removal of old dike remnants would contribute to a reduction of the risk and damage during an inundation. A systematic set of 28 flood scenarios was simulated and for each scenario an additional damage and risk assessment was carried out. It is concluded that a simple removal or total restoration will not reduce flood damage, but that this must be achieved by a strategic compartment plan. With such a plan old dike remnants and present embankments can be used to keep water away from vulnerable and valuable areas for as long as possible and to guide the floodwater to areas that are considered less vulnerable
Coastal Dynamics
No full textThis textbook on Coastal Dynamics focuses on the interrelation between physical wave, flow and sediment transport phenomena and the resulting morphodynamics of a wide variety of coastal systems. The textbook is unique in that it explicitly connects the dynamics of open coasts and tidal basins; not only is the interaction between open coasts and tidal basins of basic importance for the evolution of most coastal systems, but describing the similarities between their physical processes is highly instructive as well. This textbook emphasizes these similarities to the benefit of understanding shared processes such as nonlinearities in flow and sediment transport. Some prior knowledge with respect to the dynamics of flow, waves and sediment transport is recommended. The authors would like to track the reach and use of this Open Textbook. Therefore, they would be very pleased if you could fill out a form to provide information on your intended use of this book. The form also provides options to subscribe for update notifications and give feedback
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
Variability of shore and shoreline evolution
No full textShore and shoreline evolution both due to natural and human-induced causes or factors can be variable over a wide range of different temporal and/or spatial scales. Our capability to understand and especially predict this variability is still limited. This can lead to misinterpretation of coastal change information, which hampers informed decision making and the subsequent design and implementation of (soft) engineering interventions. Collecting and describing example observations of shore and shoreline variability is one way to support and improve such human intervention. This paper describes causes and factors for the variability and the resulting possible evolutions of wave-dominated shores and shorelines, which are illustrated by a number of case studies. The new element of this work is that the variability is described in terms of a range of different time and space scales, which helps to structure such analysis. However, it is difficult to generalise the results for arbitrary situations, especially on decadal time scales. Scientific and engineering improvements require more quantitative insight into the physical mechanisms behind the free and forced shore behaviour responsible for the variability
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
Structural Economic Effects of Large-Scale Inundation; A Simulation of the Krimpen Dike Breakage
Get PDFThe paper’s main concern is to establish a general methodology for economic loss estimation as a result of a large-scale flooding. The issue of economic loss definition is addressed in an attempt to unify the scattered definitions currently circulating in the ‘disaster’ literature. Total effect includes the direct loss to households and government, direct business interruption and induced indirect losses on production all over the country. The input-output model is proposed as a basic modelling framework. The discussion involves appropriate definition of direct and indirect costs within this framework. Adaptations to the model are proposed to account for asymmetric shock aspects such as ‘production bottlenecks’ and substitution effects. The time dimension of the model is a 2-year period. A bi-regional input-output table is utilised for tracing the inter-regional ties within the country and to estimate the disaster-induced changes of the economic structure The case study of a dike breakage in the province of South Holland in the Netherlands provides an example of modelling vast economic consequences. Two basic models are compared: a reference standard input-output damage evaluation model and adjusted models examining the impact of economic recovery of production ‘bottlenecks’ and substitution effects from imports and production transfer to other regions. It is shown that with the same level of initial disruption final loss figure depends on the ability of an economy to adjust. Whereas the presence of ‘bottlenecks’ in the after-flood situation drags the final estimate far below the reference figure, the emergence of flexible conditions for the economic response provides more optimistic results
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