679 research outputs found
Numerical analysis of a transmission problem with Signorini contact using mixed-FEM and BEM
No full text© EDP Sciences, SMAI 2011This paper is concerned with the dual formulation of the interface problem consisting of a linear partial differential equation with variable coefficients in some bounded Lipschitz domain Ω in
Rn (n ≥ 2) and the Laplace equation with some radiation condition in the unbounded exterior domain Ωc := Rn\￣Ω. The two problems are coupled by transmission and Signorini contact conditions on the interface Γ = ∂Ω. The exterior part of the interface problem is rewritten using a Neumann to Dirichlet mapping (NtD) given in terms of boundary integral operators. The resulting variational formulation becomes a variational inequality with a linear operator. Then we treat the corresponding numerical scheme and discuss an approximation of the NtD mapping with an appropriate discretization of the inverse Poincar´e-Steklov operator. In particular, assuming some abstract approximation properties and a discrete inf-sup condition, we show unique solvability of the discrete scheme and obtain the corresponding a-priori error estimate. Next, we prove that these assumptions are satisfied with Raviart- Thomas elements and piecewise constants in Ω, and continuous piecewise linear functions on Γ. We suggest a solver based on a modified Uzawa algorithm and show convergence. Finally we present some numerical results illustrating our theory
A residual based A POSTERIORI error estimator for an augmented mixed finite element method in linear elasticity
No full textIn this paper we develop a residual based a posteriori error analysis for an augmented mixed
finite element method applied to the problem of linear elasticity in the plane. More precisely,
we derive a reliable and efficient a posteriori error estimator for the case of pure Dirichlet
boundary conditions. In addition, several numerical experiments confirming the theoretical
properties of the estimator, and illustrating the capability of the corresponding adaptive
algorithm to localize the singularities and the large stress regions of the solution, are also
reported
On some properties of singular matrices
No full textAbstractSome results of Ostrowski in [5] are generalized to the case of monotonic norms
Surveying the open podcast landscape and finding our niche: Blog #1 for the Open Podcasting Project
No full textblog post#GO--GN Fellowshiphttps://go-gn.net/gogn/the-third-call-for-go-gn/Open educational practices (OEP)Student perspectivesOpen researchpodcast creatio
Introducing the "Into the Open" podcast series
No full textblog post#GO--GN Fellowshiphttps://go-gn.net/gogn/the-third-call-for-go-gn/Open Educational Practices (OEP)Student perspectivesOpen researchPodcast creatio
Small points on subvarieties of a torus
No full textLet V be a subvariety of a torus defined over the algebraic numbers. We give a qualitative and quantitative description of the set of points of V of height bounded by invariants associated to any variety containing V . Especially, we determine whether such a set is or is not dense in V . We then prove that these sets can always be written as the intersection of V with a finite union of translates of tori of which we control the sum of the degrees. As a consequence, we prove a conjecture by the first author and David up to a logarithmic factor
Altura de la rama mandibular y su relación con el ángulo SN GO-GN en radiografías cefálicas laterales digitales
No full textObjetivo: El presente estudio de investigación tiene como objetivo establecer la altura de la rama mandibular y su relación con el ángulo SN Go-Gn en radiografías cefálicas laterales digitales en pacientes de 18 a 45 años de edad de la ciudad de Cuenca-Ecuador. Materiales y Métodos: Este estudio, cuantitativo, observacional con un enfoque correlacional, se realizó en radiografías cefálicas laterales digitalizadas que reposan en el archivo de un centro radiológico de la ciudad de Cuenca - Ecuador e incluyó un total de 388 radiografías laterales escogidas bajo ciertos criterios de inclusión y exclusión. Las variables analizadas fueron altura de la rama mandibular, ángulo SN Go-Gn y sexo. Las medidas se realizaron, aplicando el software AUTOCAD 2018, por un examinador entrenado previamente para tal fin, y validados posteriormente por la autora del estudio. Los datos obtenidos de las diferentes mediciones fueron registrados en una hoja de cálculo Excel. Para evaluar la relación entre la altura de la rama mandibular y el ángulo SN Go-Gn se empleó el coeficiente de correlación r de Pearson, para la interpretación se siguió la sugerencia de Cohen (1988); correlación nula (0.00 ≤ r <0.10), correlación leve (0.10 ≤ r <0.30), correlación moderada (0.30 ≤ r <0.50) y correlación fuerte (0.50 ≤ r < 1). Para la comparación se empleó el estadístico paramétrico t-Student, la significancia considerada fue de 0.01 (p<0.01). El procesamiento de datos fue realizado en el programa estadístico SPSS V27. Resultados: Se encontró una correlación negativa fuerte, entre la altura de la rama mandibular y el ángulo SN Go-Gn (r= -0.535; p<0.001), lo que implica que a mayor altura (mm), menor ángulo (°) Conclusión: Los resultados mostraron que si existe relación entre la altura de la rama mandibular y el ángulo SN Go-Gn, en pacientes de 18 a 45 años de edad.The present research study aims to establish the height of the mandibular ramus and its relationship with the SN Go-Gn angle in digital lateral cephalic radiographs in patients from 18 to 45 years old from the city of Cuenca-Ecuador. Materials and Methods: This study, quantitative, observational with a correlational approach, was carried out on digitalized lateral cephalic radiographs that rest in the archive of a radiological center in the city of Cuenca - Ecuador and included a total of 388 lateral radiographs chosen under certain criteria of inclusion and exclusion. The variables analyzed were mandibular ramus height, SN Go-Gn angle, and sex. The measurements were made, applying the AUTOCAD 2018 software, by an examiner previously trained for this purpose, and subsequently validated by the author of the study. The data obtained from the different measurements were recorded in an Excel spreadsheet. To evaluate the relationship between the height of the mandibular ramus and the SN Go-Gn angle, the Pearson r correlation coefficient was used, for the interpretation the suggestion of Cohen (1988) was followed; null correlation (0.00 ≤ r <0.10), slight correlation (0.10 ≤ r <0.30), moderate correlation (0.30 ≤ r <0.50) and strong correlation (0.50 ≤ r < 1). For the comparison, the parametric t-Student statistic was used, the significance considered was 0.01 (p<0.01). The data processing was carried out in the statistical program SPSS V27. Results: A strong negative correlation was found between the height of the mandibular ramus and the SN Go-Gn angle (r= -0.535; p<0.001), which implies that the higher the height (mm), the lower the angle (°). Conclusion: The results showed that there is a relationship between the height of the mandibular ramus and the SN Go-Gn angle, in patients from 18 to 45 years old.
Key words: mandibular Ramus, mandibular growth0000-0002-3794-1942Especialista en OrtodonciaCuenc
The process of creating a podcast, don't make the same mistakes I did: Blog #2-B for the Open Podcasting Project
No full textblog post#GO--GN Fellowshiphttps://go-gn.net/gogn/the-third-call-for-go-gn/Open educational practices (OEP)Student perspectivesPodcast creatio
Walker-Breaker games on Gn,p
No full textThe Maker-Breaker connectivity game and Hamilton cycle game belong to the best studied games in positional games theory, including results on biased games, games on random graphs and fast winning strategies. Recently, the Connector Breaker game variant, in which Connector has to claim edges such that her graph stays connected throughout the game, as well as the Walker-Breaker game variant, in which Walker has to claim her edges according to a walk, have received growing attention. For instance, London and Pluhár studied the threshold bias for the Connector Breaker connectivity game on a complete graph Kn, and showed that there is a big difference between the cases when Maker’s bias equals 1 or 2. Moreover, a recent result by the first and third author as well as Kirsch shows that the threshold probability p for the (2: 2) Connector-Breaker connectivity game on a random graph G ∼ Gn,p is of order n−2/3+o(1). We extent this result further to WalkerBreaker games and prove that this probability is also enough for Walker to create a Hamilton cycle
Finding our open podcasting voices: Blog #2-A for the Open Podcasting Project
No full textblog post#GO--GN Fellowshiphttps://go-gn.net/gogn/the-third-call-for-go-gn/Open educational practices (OEP)Student perspectivesOpen researc
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