Search results for "Opera"
showing 10 items of 8665 documents
Non-convex power allocation games in MIMO cognitive radio networks
2013
Consideramos un escenario de reparto del espectro, basado en la detección, en una red de radio cognitiva MIMO donde el objetivo general es maximizar el rendimiento total de cada usuario de radio cognitiva optimizando conjuntamente la operación de detección y la asignación de potencia en todos los canales, bajo una restricción de interferencia para los usuarios primarios. Los problemas de optimización resultantes conducen a un juego no convexo, que presenta un nuevo desafío a la hora de analizar los equilibrios de este juego. Con el fin de hacer frente a la no convexidad del juego, utilizamos un nuevo concepto relajado de equilibrio, el equilibrio cuasi-Nash (QNE). Se demuestran las condicio…
Comparison of the shear bond strength of 3D printed temporary bridges materials, on different types of resin cements and surface treatment
2019
Background Thus, purpose of this study was to compare the shear bond strength of the resin cement and the resin modified glass ionomer cement on 3D printed temporary material for crowns and bridges in combination with different surface treatment modalities. Material and methods Test specimens VarseoSmile Temp material (Bego, Bremen, Germany) (n=64) in the form of rectangular blocks (n=32) and cylindrical test specimens (n=32) were printed using the Varseo S 3D printer (Bego, Bremen, Germany). The specimens were divided into 4 groups, with 8 specimens of each kind. Two groups (n=16 pairs) were blasted with Perlablast® Micro [PM] 50µm (Bego, Bremen, Germany) and two groups (n=16 pairs) were b…
"3D Printed Complexed Arota as A Preoperative Guidance and Postoperative Results’ Evaluation"
2021
We describe a case of 55 years old female who underwent an aortic valve replacement using a mechanical valve...
Better numerical approximation by Durrmeyer type operators
2018
The main object of this paper is to construct new Durrmeyer type operators which have better features than the classical one. Some results concerning the rate of convergence and asymptotic formulas of the new operator are given. Finally, the theoretical results are analyzed by numerical examples.
Estimates for the differences of positive linear operators and their derivatives
2019
The present paper deals with the estimate of the differences of certain positive linear operators and their derivatives. Oxur approach involves operators defined on bounded intervals, as Bernstein operators, Kantorovich operators, genuine Bernstein-Durrmeyer operators, and Durrmeyer operators with Jacobi weights. The estimates in quantitative form are given in terms of the first modulus of continuity. In order to analyze the theoretical results in the last section, we consider some numerical examples.
Frames and weak frames for unbounded operators
2020
In 2012 G\u{a}vru\c{t}a introduced the notions of $K$-frame and of atomic system for a linear bounded operator $K$ in a Hilbert space $\mathcal{H}$, in order to decompose its range $\mathcal{R}(K)$ with a frame-like expansion. In this article we revisit these concepts for an unbounded and densely defined operator $A:\mathcal{D}(A)\to\mathcal{H}$ in two different ways. In one case we consider a non-Bessel sequence where the coefficient sequence depends continuously on $f\in\mathcal{D}(A)$ with respect to the norm of $\mathcal{H}$. In the other case we consider a Bessel sequence and the coefficient sequence depends continuously on $f\in\mathcal{D}(A)$ with respect to the graph norm of $A$.
Hilbert space operators with two-isometric dilations
2021
A bounded linear Hilbert space operator $S$ is said to be a $2$-isometry if the operator $S$ and its adjoint $S^*$ satisfy the relation $S^{*2}S^{2} - 2 S^{*}S + I = 0$. In this paper, we study Hilbert space operators having liftings or dilations to $2$-isometries. The adjoint of an operator which admits such liftings is characterized as the restriction of a backward shift on a Hilbert space of vector-valued analytic functions. These results are applied to concave operators (i.e., operators $S$ such that $S^{*2}S^{2} - 2 S^{*}S + I \le 0$) and to operators similar to contractions or isometries. Two types of liftings to $2$-isometries, as well as the extensions induced by them, are construct…
Innovation Policies for Regional Structural Change: Combining Actor-Based and System-Based Strategies
2018
This chapter analyses opportunities and challenges for regional innovation policies designed to promote new path development in different types of regional innovation systems (RISs). RISs differ enormously in their capacity to develop new growth paths due to pronounced differences in endogenous potentials and varying abilities to attract and absorb exogenous sources for new path development. We distinguish between different types of regional industrial path development, which reflect various degrees of radicalness of regional structural change. The chapter offers a conceptual analysis of conditions and influences that enable and constrain new path development in different types of RISs and …
Identity profiles and digital engagement among Finnish high school students
2018
Developing a stable personal identity is considered a more precarious task in today’s society than hitherto. Skilful digital engagement may, however, constitute a valuable asset in necessary identity exploration and commitment. Applying a person-oriented approach, we examined for the first time how identity profiles are associated with digital engagement, operationalized as digital competence, gaming seriousness, type of internet activity and excessive ICT use. After controlling for gender, life satisfaction and parental SES, this study of a Finnish high school sample (N = 932) revealed that adolescents with future commitments and some exploration of options (achievement, searching moratori…
Geopolítica de la cooperación transfronteriza. Balance y retos (de la COVID-19)
2022
Interpretar la cooperación transfronteriza desde la geopolítica nos permite aportar una mirada multiescalar, sopesando las estrategias de las comunidades locales en tiempos de blindajes fronterizos de los Estados como los promovidos en los últimos años por la Unión Europea, Mercosur o el Tratado de Libre Comercio de América del Norte. Por tanto, se analizan, desde esta perspectiva geopolítica, las fortalezas y las debilidades de la cooperación transfronteriza en diferentes escenarios: África, América y Europa. Así mismo, se abordan los retos y desafíos futuros, en particular los que surgen tras la pandemia de la COVID-19. Este volumen intenta responder también a la cuestión de si la coopera…