Search results for "Opera"
showing 10 items of 8665 documents
Liftings and extensions of operators in Brownian setting
2020
We investigate the operators T on a Hilbert space H which have 2-isometric liftings S with the property S ∗ S H ⊂ H . We show that such liftings are closely related to some extensions of T, which h...
Explicit expressions for Sturm-Liouville operator problems
1987
Throughout this paper H will denote a complex separable Hilbert space and L(H) denotes the algebra of all bounded linear operators on H. If T lies in L(H), its spectrum σ(T) is the set of all complex numbers z such zI–T is not invertible in L(H) and its compression spectrum σcomp(T) is the set of all complex numbers z such that the range (zI-T)(H) is not dense in H ([3, p. 240]). This paper is concerned with the Sturm–Liouville operator problemwhere λ is a complex parameter and X(t), Q, Ei, Fi for i = l,2, and t∈[0,a], are bounded operators in L(H). For the scalar case, the classical Sturm-Liouville theory yields a complete solution of the problem, see [4], and [7]. For the finite-dimension…
Distribution of Large Eigenvalues for Elliptic Operators
2019
In this chapter we consider elliptic differential operators on a compact manifold and rather than taking the semi-classical limit (h →), we let h = 1 and study the distribution of large eigenvalues. Bordeaux Montrieux (Loi de Weyl presque sure et resolvante pour des operateurs differentiels non-autoadjoints, these, CMLS, Ecole Polytechnique, 2008. https://pastel.archives-ouvertes.fr/pastel-00005367, Ann Henri Poincare 12:173–204, 2011) studied elliptic systems of differential operators on S1 with random perturbations of the coefficients, and under some additional assumptions, he showed that the large eigenvalues obey the Weyl law almost surely. His analysis was based on a reduction to the s…
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
A dynamic performance management approach to support local strategic planning
2015
In spite of efforts devoted in the last decades to local strategic planning, such field of research and practice has been frequently characterized by a lack of implementation. We argue here that this phenomenon is due to the limitations of the static and linear approach to local strategic planning in fostering the development of common shared view among policy makers on the relevant system's structure and behavior. By means of a case-study, we illustrate how an approach based on system dynamics modeling applied to Performance Management can be useful to overcome such weaknesses. The proposed approach enhances a better understanding of the causes and effects related to adopted policies, unde…
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 …
Simultaneous optimization of harvest schedule and measurement strategy
2013
In many recent studies, the value of forest inventory information in the harvest scheduling has been examined. Usually only the profitability of measuring simultaneously all the stands in the area is examined. Yet, it may be more profitable to concentrate the measurement efforts to some subset of them. In this paper, the authors demonstrate that stochastic optimization can be used for defining the optimal measurement strategy simultaneously with the harvest decisions. The results show that without end-inventory constraints, it was most profitable to measure the stands that were just below the medium age. Measuring the oldest stands was not profitable at all. It turned out to be profitable t…
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}^{*…