1,721,012 research outputs found
Bayesian Population Size Estimation With a Single Sample
Full text linkLa stima della numerosit`a di una popolazione `e un problema comune a vari ambiti di applicazione. Le procedure di stima sono solitamente basate sul noto metodo cattura-ricattura, il quale comporta elevati costi e disturbo della popolazione. Tali considerazioni hanno stimolato la ricerca di tecniche che permettano di ottenere un stima utilizzando un unico campione. Hettiarachchige (Hettiarachchige, C.K.H.: Inference from single occasion capture experiments using genetic markers. PhD Thesis (2016)) propone un metodo applicabile nel caso in cui la popolazione sia composta di due sole generazioni: un gruppo di unit`a generatrici ed uno di unit`a generate. L’obiettivo del nostro lavoro `e quello di ottenere un’estensione Bayesiana dell’originale modello frequentista. Risultati preliminari evidenziano accuratezza degli stimatori Bayesiani sensibilmente migliore rispetto alle alternative frequentiste.The estimation of the size of a finite population is a problem encountered in a variety of applications. One standard statistical approach relies on markrecapture sampling, which may require high costs and annoyance to the population of interest. These considerations have motivated the search for alternative sampling strategies that allow to estimate the size of a population from a single capture. Hettiarachchige (Hettiarachchige, C.K.H.: Inference from single occasion capture experiments using genetic markers. PhD Thesis (2016)) proposes a method that is viable when the population is made of only two generations: a group of generators and one of generated units. We investigate Bayesian methods alternative to the frequentist estimators used by the original author. Preliminary results give evidence of competing performance of the Bayesian approach, which in some cases sensibly outperforms the frequentist alternatives
A semi-quantitative risk assessment method in process plants: Huntsman tioxide Europe-Ternate plant experience
No full textThe purpose of the present work was to develop a methodology for the risk assessment in workplace for Huntsman Ternate plant, pursuant the Legislative Decree n. 81/08 and subsequent amendments. Huntsman internal procedure focused on the processes risk management, and it was developed in order to homogeneously classify accident scenarios in all Huntsman plants; but it wasn't effective to assess the hazards related to work operations and workplace. The first kind of events are heavier than occupational accidents, as well as less frequent; therefore, the application of Huntsman procedure as it was would have provoked a loss of significance of results obtained. Thus, it was elaborated a semi quantitative method of risk assessment in workplace, combining the techniques derived by the national regulations and the company procedure, in order to reach a more effective method to evaluate the risks and communicate to the associates the risks evaluation outputs
A non-parametric Hawkes process model of primary and secondary accidents on a UK smart motorway
No full textA self-exciting spatiotemporal point process is fitted to incident data from the UK National Traffic Information Service to model the rates of primary and secondary accidents on the M25 motorway in a 12-month period during 2017–2018. This process uses a background component to represent primary accidents, and a self-exciting component to represent secondary accidents. The background consists of periodic daily and weekly components, a spatial component and a long-term trend. The self-exciting components are decaying, unidirectional functions of space and time. These components are determined via kernel smoothing and likelihood estimation. Temporally, the background is stable across seasons with a daily double peak structure reflecting commuting patterns. Spatially, there are two peaks in intensity, one of which becomes more pronounced during the study period. Self-excitation accounts for 6–7% of the data with associated time and length scales around 100 min and 1 km, respectively. In-sample and out-of-sample validation are performed to assess the model fit. When we restrict the data to incidents that resulted in large speed drops on the network, the results remain coherent
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
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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