1,720,952 research outputs found
Consideration of risk in hydraulic design of bank protection using Reno matresses and riprap
No full textThis report discusses channel stabilization design by erosion protection measures considering risk analysis. Although many different erosion protection measures have been used, this report only considers rip-rap and wire enclosed rock (in mattresses) which are two of the most widely used methods of erosion protection. The purpose of erosion protection and channel stabilization is, of course, to maintain a channel and its banks and/or bed in a relatively fixed location to protect property, structures or other development from erosion related damage. Because rivers are quite dynamic and development continues along rivers and other types of channels, the need for erosion protection and bank stabilization will continue. Chapter II discusses briefly the dynamic nature of rivers and the need for erosion protection and channel stabilization. Various types of engineering analysis are required in developing an erosion protection design. These include hydrology, hydraulics, geomorphic, erosion and sediment transport. Where ship or barge traffic is of concern, ship-generated waves and other related impacts should also be accounted for. Chapter III discusses the data and analysis required for designing erosion protection and channel stabilization projects. This is by no means a comprehensive discussion of these topics but is meant to serve as an introduction and guide to the subject. The reader is encouraged to refer to the references given on these topics for further information. Chapter IV discusses common failure modes of erosion protection projects. There are a number of distinct and independent causes of failure. Each one alone can be sufficient to induce failure or they may, in some cases, act in concert to induce failure. A fairly comprehensive list of potential modes of failure is included ranging from the obvious to the more obscure and often overlooked. Flowing water causes forces or stresses to act on the bed and banks of a river. These are the forces that cause erosion and attempt to damage any erosion protection. They basically include shear, lift and drag forces acting on each individual particle on the bed and banks. The beginning portion of Chapter V analyzes the hydrodynamic forces due to flowing water acting on erosion protection works. Then based on the most important or frequent modes of failure and an evaluation of the forces acting on rip-rap or wire enclosed rock, methods to evaluate the probability of failure for each of the selected modes were developed. The remqinder of Chapter V covers this topic. The methods presented can be used either directly in a design application or as a tool in evaluating an existing design. Chapter VI outlines these methodologies in step by step format and then gives an example to follow for each procedure. Because the individual modes of failure can be treated independently, the total probability of failure is obtained by summing the individual probabilities. If the probability of failure thus obtained is too high for the given event, redesign is required. The next chapter (Chapter VII) is called "Risk Analysis." This type of an analysis actually is an economic optimization procedure but it has been previously called risk analysis in the literature. Risk analysis consists basically of designing a structure or whatever in order to minimize overall costs. These overall costs include both the initial construction costs as well as long term maintenance and repair costs. It is based on the logic that one may design something that can withstand the forces of a 1,000 year flood but the initial cost and therefore the total cost would be unreasonably high. One may also design a project to withstand the forces of a two year event which would have a very low initial cost but again the overall cost would be very high because of the frequency of maintenance and/or repair and replacement costs. The purpose of risk analysis is to find the minimum overall cost by varying the hydrologic return period of a project and associated designs and their costs in order to minimize the overall project cost. The design is selected that then gives this minimum cost or at least is in the range where costs are near the minimum. Chapter VIII contains the summary and conclusions. References and an appendix of terminology follows the final chapter
Hydraulic test to develop design criteria for the use of Reno mattresses
No full textThe present study was aimed at evaluating the performance of Maccaferri mattress products when used as river and canal bank and bed revetment. A hydraulic testing program was developed and undertaken to provide experimental data pertaining to the performance of reno mattresses. Test data were utilized to develop reliable design criteria for Maccaferri reno mattresses. Major tasks include: 1. To review the existing design methodologies and field application experience pertaining to gabions and mattresses. 2. To determine the roughness of revet mattresses. 3. To evaluate requirements of underlying granular filters or filter cloth layers. 4. To evaluate the stability of mattresses subjected to various flow conditions. 5. To analyze test results and develop design criteria applicable to mattress protection designs
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
A rationale for the payback criterion
Get PDFTextbooks on financial management have emphasized the shortcomings of the payback criterion for decades. However, empirical evidence suggests that in actual capital budgeting procedures the payback method is used quite regularly. Mostly, it is implemented supplementary to net present value or internal rate of return, but small companies tend to rely on payback times as single criterion. A convincing theoretical foundation for the observed use of the payback criterion is lacking. Consequently, our goal is to provide such an explanation for the payback criterion’s popularity. We demonstrate from a decision theoretical perspective how relying on payback times simplifies investment decisions in modern organizations. Gathering information from different management levels and ensuring the utilization of individual skills requires a multi-stage capital budgeting process. Accordingly, we consider fundamental organizational features of this process with respect to their impact on the payback method’s use. For this purpose, we built upon almost stochastic dominance (ASD) as modeling device. Firstly, we show that applying his concept allows to include the risk preferences of all relevant decision makers into the analysis. Secondly, we illustrate that the criteria derived from this model help conveying these preferences to those who do the preparatory work preceding the final decision. To some extent, these new criteria are generalizations of payback times. This finding provides a potential explanation for the payback’s persisting prominence.
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
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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