1,721,269 research outputs found
Letter re: C. L. Smith
No full textLetter to Tom Connally from Amon Giles Carter Sr. asking Connally to aid C. L. Smith in finding a place of service to the Arm
Letter from John C. L. Smith to Brigham Young, October 10, 1854
No full textPaiuteLetter to Brigham Young from John C. L. Smith discussed how the Indians in Iron County were dissatisfied with their relationships with the settlers there
Composite multilinearity, epistemic uncertainty and risk achievement worth
No full textRisk achievement worth is one of themostwidely utilized importancemeasures. RAWis defined as the ratio
of the riskmetric value attained when a component has failed over the base case value of the riskmetric. Traditionally,
both the numerator and denominator are point estimates. Relevant literature has shown that
inclusion of epistemic uncertainty (i) induces notable variability in the point estimate ranking and (ii) causes
the expected value of the risk metric to differ from its nominal value. We investigate the conditions under
which the equality of the nominal and expected values of a reliability risk metric holds. We then study
howthe presence of epistemic uncertainty affects RAWand the associated ranking.We propose an extension
of RAW(called ERAW)which allows one to obtain a ranking robust to epistemic uncertainty.We discuss the
properties of ERAWand the conditions under which it coincides with RAW. Weapply our findings to a probabilistic
risk assessment model developed for the safety analysis of NASA lunar space missions
A Study of Interactions in the Risk Assessment of Complex Engineering Systems: an Application to Space PSA
No full textRisk-managers are often confronted with the evaluation of operational policies in which two or more system components are simultaneously affected by a change. In these instances, the decision-making process should be informed by the relevance of interactions. However, because of system and model complexity, a rigorous study for determining whether and how interactions quantitatively impact operational choices has not been developed yet. In the light of the central role played by the multilinearity of the decision-support models, we investigate of the presence of interactions in multilinear functions first. We identify interactions that can be a-priori excluded from the analysis. We introduce sensitivity measures that apportion the model output change to factors individual and interaction contributions in an exact fashion. The sensitivity measures are linked to graphical representation methods as tornado diagrams and Pareto charts, and a systematic way of inferring managerial insights is presented. We then specialize the findings to reliability and probabilistic safety assessment (PSA) problems. We set forth a procedure for determining the magnitude of changes that make interactions relevant in the analysis. Quantitative results are discussed by application to a PSA model developed at NASA to support decision-making in space mission planning and design. Numerical findings show that sub-optimal decisions concerning the components on which to focus managerial attention can be made, if the decision-making process is not informed by the relevance of interactions
Global Sensitivity Measures from Given Data
No full textSimulation models support managers in the solution of complex problems. International agencies recommend uncertainty
and global sensitivity methods as best practice in the audit, validation and application of scientific codes. However, numerical complexity, especially in the presence of a high number of factors, induces analysts to employ less informative but numerically cheaper methods. This work introduces a design for estimating global sensitivity indices from given data (including simulation input-output data), at the minimum computational cost. We address the problem starting with a statistic based on the L1-norm. A formal definition of the estimators is provided and
corresponding consistency theorems are proved. The determination of confidence intervals through a bias-reducing
bootstrap estimator is investigated. The strategy is applied in the identification of the key drivers of uncertainty for
the complex computer code developed at the National Aeronautics and Space Administration (NASA) assessing the
risk of lunar space missions. We also introduce a symmetry result that enables the estimation of global sensitivity
measures to datasets produced outside a conventional input-output functional framewor
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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