1,721,031 research outputs found
Deviation maximization for rank-revealing QR factorizations
Full text linkIn this paper, we introduce a new column selection strategy, named here “Deviation Maximization”, and apply it to compute rank-revealing QR factorizations as an alternative to the well-known block version of the QR factorization with the column pivoting method, called QP3 and currently implemented in LAPACK’s xgeqp3 routine. We show that the resulting algorithm, named QRDM, has similar rank-revealing properties of QP3 and better execution times. We present experimental results on a wide data set of numerically singular matrices, which has become a reference in the recent literature
Accurate detection of hidden material changes as fictitious heat sources
No full textIn this article we present a numerical method for the estimation of hidden material changes, interpreted as fictitious source terms. The method adapts the parameters of its reference model in order to cancel the estimated fictitious source terms and thus it indirectly estimates the hidden material changes. The novelty of this method is triple: first, a parsimonious minimization strategy that effectively avoids local minima, by using the maximum principle as a barrier against falling into; second, an error indicator based on estimates of fictitious heat sources, instead of the temperatures-prediction-error, because it is smeared by diffusion; third, the adaptation of model parameters is computed without the problematic matrix inversion which would arise in Newton-based procedures. As a particular example application, we show that, in thermographic experiments for hidden corrosion detection, the gradient of the temperatures-prediction-error, often used in the literature, is quite inefficient, while the fictitious-source-term estimation behaves intrinsically better. Its accuracy and moderate computational demand are highlighted in the numerical tests. Moreover, this approach is applicable to general hidden material change problems
Peritoneal sarcomatosis 5 years after laparoscopic morcellation of uterine leiomyoma
No full textIn 2011, a 40-year-old woman underwent laparoscopic myomectomy with intraabdominal morcellation. Histology report showed leiomyoma without atypia, necrosis, or mitosis. In 2016, she complained of left lower quadrant pain; ultrasound examination revealed a left hypogastric mass in the site of trocar placement. Percutaneous biopsy results showed a low-grade endometrial stromal sarcoma (LGESS). At laparoscopy, we observed: multiple nodules on uterine serosa, left annex, vesical peritoneum (Figure 1), Douglas pouch (Supplementary Video1), previous left pelvic trocar site (Figure 2), greater omentum (Figure 3), and right/left diaphragm
Accelerating the Lawson-Hanson NNLS solver for large-scale Tchakaloff regression designs
Full text linkWe deal with the problem of computing near G-optimal compressed designs for high-degree polynomial regression on fine discretizations of 2d and 3d regions of arbitrary shape. The key tool is Tchakaloff-like compression of discrete probability measures, via an improved version of the Lawson-Hanson NNLS solver for the corresponding full and large-scale underdetermined moment system, that can have for example a size order of 10ˆ3 (basis polynomials) x 10ˆ4 (nodes)
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
FIBROMI UTERINI. SANDOZ. Therapeutic Reviews in Ginecologia. Allegato Vol. 5 Journal of Endometriosis and Pelvic Pain Disorders.
No full textVariations 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
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