Search results for " Operator"
showing 10 items of 931 documents
Gaussian plane and spherical means in separable Hilbert spaces
1982
Operator (Quasi-)Similarity, Quasi-Hermitian Operators and All that
2016
Motivated by the recent developments of pseudo-Hermitian quantum mechanics, we analyze the structure generated by unbounded metric operators in a Hilbert space. To that effect, we consider the notions of similarity and quasi-similarity between operators and explore to what extent they preserve spectral properties. Then we study quasi-Hermitian operators, bounded or not, that is, operators that are quasi-similar to their adjoint and we discuss their application in pseudo-Hermitian quantum mechanics. Finally, we extend the analysis to operators in a partial inner product space (pip-space), in particular the scale of Hilbert space s generated by a single unbounded metric operator.
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
Deformed Canonical (anti-)commutation relations and non-self-adjoint hamiltonians
2015
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…
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…
On elliptic equations involving the 1-Laplacian operator
2018
El objetivo de esta tesis doctoral es dar a conocer los resultados obtenidos sobre existencia, unicidad y regularidad de las soluciones de diferentes ecuaciones elípticas regidas por el operador 1-laplaciano. El primer capítulo está dedicado al estudio de la ecuación - div (Du/|Du|) + g(u) |Du| = f(x) en un subconjunto abierto y acotado U de R^N con frontera Lipschitz, con la condición de Dirichlet u=0 en la frontera, tomando una función f positiva y siendo g una función real, continua y positiva. Por un lado, obtenemos soluciones no acotadas cuando el dato f pertenece al espacio de Marcinkiewicz L^{N,\infty}(U), por lo que debemos introducir la definición apropiada para este tipo de soluci…
Constant sign and nodal solutions for parametric anisotropic $(p, 2)$-equations
2021
We consider an anisotropic ▫$(p, 2)$▫-equation, with a parametric and superlinear reaction term.Weshow that for all small values of the parameter the problem has at least five nontrivial smooth solutions, four with constant sign and the fifth nodal (sign-changing). The proofs use tools from critical point theory, truncation and comparison techniques, and critical groups. Spletna objava: 9. 9. 2021. Abstract. Bibliografija: str. 1076.
EFFICACIA DI UN INTERVENTO FORMATIVO RIVOLTO AGLI OPERATORI SANITARI DELL'AZIENDA OSPEDALIERA UNIVERSITARIA (AOU) POLICLINICO "P. GIACCONE" DI PALERM…
2017
INTRODUZIONE: La vaccinazione antin uenzale rappresenta la misura preventiva più ef cace nel limitare la diffusione del virus in uenzale ed il Ministero della Salute raccomanda fortemente tale misura precauzionale a tutti gli operatori sanitari (OS). Gli OS sono ripetutamente esposti al virus, rappresentando una delle principali fonti di contagio per i pazienti e anticipando la malattia in uenzale rispetto alla popolazione generale. In numerosi studi, gli OS hanno riportato che la strategia preferita per implementare le coperture antin uenzali tra gli stessi, era l’organizzazione di corsi di formazione multidisciplinare sulla tematica. In questa ottica è stato svolto un intervento formativo…