1,720,984 research outputs found
The contribution of Artificial Adaptive System to limit the influence of systematic errors in the definition of the kinematic behavior of an extremely-slow landslide
No full textThis paper describes the application of some new mathematical algorithms, developed at Semeion
Research Center and based on Artificial Adaptive System (AAS), to the redundant measurements of
displacement of an extremely-slow landslide that may be affected by some systematic errors. The main aim
is to understand if AAS may overcome their influence in the definition of the landslide kinematic behavior
thus being able to use the measurements even though they differ by systematic errors. This would be a
particularly good result for the monitoring of extremely-slow landslides that move at displacement rates
less than 16 mm/year and can be recognized only with instrumentation, usually of geodetic type for the
ground surface and inclinometers for the subsurface. In the short time, displacements are so small that
they may include systematic errors of the same order of magnitude that can neither be identified nor
reduced. For the monitoring of extremely-slow landslides it is therefore recommended to use redundant
measurement systems and check the reliability of data by comparing the displacements. This paper shows
how the use of the Artificial Adaptive System may get the information on the landslide kinematic even
when there is no agreement between displacements measured with the different techniques. The
validation of these results was made by comparing them with the well-known data field and a good
agreement was found
Entidades geográficas difusas. Metódos de construção e processamento
No full textUm dos métodos utilizados para representar a incerteza posicional de entidades geográficas (EGs) é baseado na utilização de conjuntos difusos, construindo EGs com extensão espacial difusa, denominadas neste trabalho de Entidades Geográficas Difusas (EGDs). Uma das maiores dificuldades da construção de EGDs tem sido a construção das funções de pertença que caracterizam os conjuntos difusos utilizados para representar a sua localização geográfica. Assim, apresentam-se nesta dissertação métodos de construir essas funções de pertença baseados em interpretações dos graus de pertença normalmente utilizadas noutros contextos, nomeadamente como graus de semelhança, como verosimilhanças e baseadas em conjuntos aleatórios, apresentando-se exemplos práticos da sua aplicação à informação geográfica.
Como é inevitável existirem erros e incerteza na informação geográfica, a utilização de EGDs em Sistemas de Informação Geográfica (SIGs) pode ser uma mais valia. No entanto, a sua utilização nestes sistemas implica não só a sua representação mas também o seu processamento. É então necessário desenvolver operadores capazes de processar EGDs. Estes operadores podem ter resultados clássicos ou difusos, permitindo os operadores com resultados difusos propagar a incerteza dos dados para os resultados das operações, dando informação acerca do grau de exactidão que lhes está associado. Sendo o cálculo de áreas e perímetros operações básicas de qualquer SIG, e como não tinham sido ainda desenvolvidos operadores que permitissem obter valores difusos para estas grandezas, construíram-se operadores para calcular a área e o perímetro difusos de EGDs. Ambos os operadores têm como resultado números difusos, o que permite não só propagar a incerteza na posição das EGDs para o valor da área e do perímetro, bem como para os resultados de quaisquer operações difusas que utilizem os seus valores. Para ilustrar esta capacidade, calculou-se um valor difuso para a compacidade de uma EGD utilizando os resultados obtidos com os novos operadores para a área e o perímetro
Interval linear systems as a necessary step in fuzzy linear systems
Full text linkInternational audienceThis article clarifies what it means to solve a system of fuzzy linear equations, relying on the fact that they are a direct extension of interval linear systems of equations, already studied in a specific interval mathematics literature. We highlight four distinct definitions of a systems of linear equations where coefficients are replaced by intervals, each of which based on a generalization of scalar equality to intervals. Each of the four extensions of interval linear systems has a corresponding solution set whose calculation can be carried out by a general unified method based on a relatively new concept of constraint intervals. We also consider the smallest multidimensional intervals containing the solution sets. We propose several extensions of the interval setting to systems of linear equations where coefficients are fuzzy intervals. This unified setting clarifies many of the anomalous or inconsistent published results in various fuzzy interval linear systems studies
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
Constrained intervals and interval spaces
No full textConstrained intervals, intervals as a mapping from [0, 1] to polynomials of degree one (linear functions) with non-negative slopes, and arithmetic on constrained intervals generate a space that turns out to be a cancellative abelian monoid albeit with a richer set of properties than the usual (standard) space of interval arithmetic. This means that not only do we have the classical embedding as developed by H. Radström, S. Markov, and the extension of E. Kaucher but the properties of these polynomials. We study the geometry of the embedding of intervals into a quasilinear space and some of the properties of the mapping of constrained intervals into a space of polynomials. It is assumed that the reader is familiar with the basic notions of interval arithmetic and interval analysis. © 2013 Springer-Verlag Berlin Heidelberg.Department of Mathematics University of Colorado Denver, DenverDepartamento de Matemática Aplicada UNESP, São José do Rio PretoDepartamento de Matemática Aplicada UNESP, São José do Rio Pret
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
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Two numerical methods for the solutions of optimal control problems with computed error bounds using the maximum principle of pontryagin
Full text linkA simplification of the proof of the maximum principle of
Pontryagin is obtained for constrained and unconstrained optimal control
problems. Two numerical methods for solving optimal control problems
with guaranteed error bounds using the maximum principle of Pontryagin
and interval analysis are derived
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
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