Search results for "Operator"
showing 10 items of 1427 documents
On the fractional integral of Weyl inL p
1994
Polaroid-Type Operators
2018
In this chapter we introduce the classes of polaroid-type operators, i.e., those operators T ∈ L(X) for which the isolated points of the spectrum σ(T) are poles of the resolvent, or the isolated points of the approximate point spectrum σap(T) are left poles of the resolvent. We also consider the class of all hereditarily polaroid operators, i.e., those operators T ∈ L(X) for which all the restrictions to closed invariant subspaces are polaroid. The class of polaroid operators, as well as the class of hereditarily polaroid operators, is very large. We shall see that every generalized scalar operator is hereditarily polaroid, and this implies that many classes of operators acting on Hilbert s…
Deformed Canonical (anti-)commutation relations and non-self-adjoint hamiltonians
2015
Estudio de validación de los parámetros dinámicos de respuesta a fluidos, variación de volumen sistólico (VVS) y variación de presión de pulso (VPP),…
2021
Introducción En cirugía de resección pulmonar, se recomienda la fluidoterapia restrictiva debido al alto riesgo de lesión pulmonar aguda postresección atribuida al uso liberal de fluidos. Sin embargo, esta terapia puede dar lugar a hipoperfusión vascular y por tanto aumento de la morbimortalidad. La fluidoterapia intraoperatoria debe ser individualizada para cada paciente, ajustando el aporte o restricción de fluidos a fin de optimizar el gasto cardíaco y evitar lesiones en órganos vitales. La fluidoterapia guiada por objetivos permite realizar esta individualización de fluidos mediante el análisis de los parámetros VVS y VPP. El objetivo principal de este estudio es la validación de VVS y …
Numerical Recovery of Source Singularities via the Radiative Transfer Equation with Partial Data
2013
The inverse source problem for the radiative transfer equation is considered, with partial data. Here we demonstrate numerical computation of the normal operator $X_{V}^{*}X_{V}$ where $X_{V}$ is the partial data solution operator to the radiative transfer equation. The numerical scheme is based in part on a forward solver designed by F. Monard and G. Bal. We will see that one can detect quite well the visible singularities of an internal optical source $f$ for generic anisotropic $k$ and $\sigma$, with or without noise added to the accessible data $X_{V}f$. In particular, we use a truncated Neumann series to estimate $X_{V}$ and $X_{V}^{*}$, which provides a good approximation of $X_{V}^{*…
User experience targets as design drivers:A case study on the development of a remote crane operator station
2013
In recent years, the notion of user experience, or UX, as an essential aspect to be addressed in the design and development of technologies has been increasingly discussed. In this paper, we present a case study in which we have used UX targets as the main design drivers and focus areas in developing a new remote operator station user interface for container cranes. UX targets describe the experiential qualities to which the product design should aim at. However, taking UX targets into consideration during product design is challenging, because only little is known about how they would be best operationalized to serve the different phases of the design process. Through our case study, we de…
On optimal relay placement for improved performance in non-coverage limited scenarios
2014
Low power nodes have been a hot topic in research, standardization, and industry communities, which is typically considered under an umbrella term called heterogeneous networking. In this paper we look at the problem of deploying optimally low power nodes in the context of relay networking, when an operator connects low power nodes (or small cells) via the wireless backhaul that uses the same spectrum and the same wireless access technology. We present an analytical model that can calculate optimal coordinates for low power nodes based on the input parameters, such as preferred number of nodes, their transmission power, parameters of the environment etc. The analytical calculations are comp…
Efficient Time Integration of Maxwell's Equations with Generalized Finite Differences
2015
We consider the computationally efficient time integration of Maxwell’s equations using discrete exterior calculus (DEC) as the computational framework. With the theory of DEC, we associate the degrees of freedom of the electric and magnetic fields with primal and dual mesh structures, respectively. We concentrate on mesh constructions that imitate the geometry of the close packing in crystal lattices that is typical of elemental metals and intermetallic compounds. This class of computational grids has not been used previously in electromagnetics. For the simulation of wave propagation driven by time-harmonic source terms, we provide an optimized Hodge operator and a novel time discretizati…
Operator Revenue Analysis for Device-to-Device Communications Overlaying Cellular Network
2018
Device-to-device (D2D) communications has recently gathered significant research interest due to its efficient utilization of already depleting wireless spectrum. In this article, we considered a scenario where D2D users communicate in the presence of cellular users in an overlay network setup. In order to analyze the revenue of service providers in monetary terms, the paper provides exact expressions of operator profit for both D2D and cellular users. More specifically, we take into account different network parameters including user density, transmit power and channel variations to understand their impact on the total revenue of the operator. Finally, we derive the balancing value of freq…
Factores de riesgo de la fibrilación auricular tras la cirugía torácica
2023
La fibrilación auricular tras la cirugía torácica (FAPO) se ha identificado como la complicación cardíaca más frecuente tras la cirugía torácica no cardíaca, resaltándose el amplio rango de incidencia, entre el 1.2% y el 25.8%. Ello se ha atribuido a factores como: (a) ausencia de una definición uniforme de FAPO, (b) distintos procedimientos quirúrgicos englobados en la misma serie, (c) inclusión de pacientes con diferente indicación quirúrgica, (d) variabilidad en la monitorización postoperatoria, (e) inclusión de pacientes con el antecedente personal de fibrilación auricular, y (f) observancia de otras arritmias cardíacas. Además, a pesar de la identificación de factores predictivos y de …