1,720,983 research outputs found
On some applications of ant colony optimization metaheuristic to structural optimization problems
No full textA convergent adaptive wavelet-Rothe method for elastoplastic hardening
No full textThis paper is concerned with the development of adaptive wavelet methods for the hardening problem in elastoplasticity. We propose a Rothe method using some implicit scheme in time. Then, we consider a standard elastic predictor-plastic corrector method. The (non-linear) correction is performed by some convergent scheme such as a Newton-Raphson iteration or suitable modifications of it. Thus, it remains to solve Helmholtz-type problems with varying right-hand sides. These are solved by the convergent adaptive wavelet method introduced by Cohen, Dahmen, and DeVore.
In the plastic correction, the trial strain might have to be corrected according to pointwise formulated hardening conditions. We propose an adaptive corrector method based on biorthogonal B-splines. This allows a fully adaptive stress correction. We obtain an overall convergent method. Some preliminary numerical results are presented
A numerical investigation on the size effect of fiber-reinforced concrete specimens in crack propagation
No full textOn some applications of ant colony optimization metaheuristic to plane truss optimization
No full textAnt colony optimization metaheuristic (ACO) represents
a new class of algorithms particularly suited to solve
real-world combinatorial optimization problems. ACO algorithms,
published for the first time in 1991 by M. Dorigo
[Optimization, learning and natural algorithms (in Italian).
Ph.D. Thesis, Dipartimento di Elettronica, Politecnico di
Milano, Milan, 1992] and his coworkers, have been applied,
particularly starting from 1999 (Bonabeau et al., Swarm intelligence:
from natural to artificial systems, Oxford University
Press, New York, 1999; Dorigo et al., Artificial life
5(2):137–172, 1999; Dorigo and Di Caro, Ant colony optimization:
a new metaheuristic, IEEE Press, Piscataway, NJ,
1999; Dorigo et al., Ant colony optimization and swarm intelligence,
Springer, Berlin Heidelberg NewYork, 2004; Dorigo
and Stutzle, Ant colony optimization, MIT Press, Cambridge,
MA, 2004), to several kinds of optimization problems such as
the traveling salesman problem, quadratic assignment problem,
vehicle routing, sequential ordering, scheduling, graph
coloring, management of communications networks, and so
on. The ant colony optimization metaheuristic takes inspiration
from the studies of real ant colonies’ foraging behavior.
The main characteristic of such colonies is that individuals
have no global knowledge of problem solving but communicate
indirectly among themselves, depositing on the ground
a chemical substance called pheromone, which influences
probabilistically the choice of subsequent ants, which tend to
follow paths where the pheromone concentration is higher.
Such behavior, called stigmergy, is the basic mechanism that
controls ant activity and permits them to take the shortest
path connecting their nest to a food source. In this paper, it is
shown how to convert natural ant behavior to algorithms able
to escape from local minima and find global minimum solutions
to constrained combinatorial problems. Some examples
on plane trusses are also presente
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
- …
