Search results for " Program"

Resolvent estimates for the magnetic Schrödinger operator in dimensions $$\ge 2$$

2019

It is well known that the resolvent of the free Schr\"odinger operator on weighted $L^2$ spaces has norm decaying like $\lambda^{-\frac{1}{2}}$ at energy $\lambda$. There are several works proving analogous high-frequency estimates for magnetic Schr\"odinger operators, with large long or short range potentials, in dimensions $n \geq 3$. We prove that the same estimates remain valid in all dimensions $n \geq 2$.

PT-symmetry and Schrödinger operators. The double well case

2015

We study a class of $PT$-symmetric semiclassical Schrodinger operators, which are perturbations of a selfadjoint one. Here, we treat the case where the unperturbed operator has a double-well potential. In the simple well case, two of the authors have proved in [6] that, when the potential is analytic, the eigenvalues stay real for a perturbation of size $O(1)$. We show here, in the double-well case, that the eigenvalues stay real only for exponentially small perturbations, then bifurcate into the complex domain when the perturbation increases and we get precise asymptotic expansions. The proof uses complex WKB-analysis, leading to a fairly explicit quantization condition.

Improving the Representativeness of a Simple Random Sample: An Optimization Model and Its Application to the Continuous Sample of Working Lives

2020

This paper proposes an optimization model for selecting a larger subsample that improves the representativeness of a simple random sample previously obtained from a population larger than the population of interest. The problem formulation involves convex mixed-integer nonlinear programming (convex MINLP) and is, therefore, NP-hard. However, the solution is found by maximizing the size of the subsample taken from a stratified random sample with proportional allocation and restricting it to a p-value large enough to achieve a good fit to the population of interest using Pearson&rsquo

¿Cómo deciden les jóvenes la transición a la educación postobligatoria? Diferencias entre centros públicos y privados-concertados

2017

Background of INCASI Project H2020-MSCA-RISE-2015 GA 691004. WP1: Compilation El objetivo del presente artículo es examinar el papel que juega la titularidad del centro en el que se cursa la educación secundaria obligatoria (ESO) en la decisión de transitar a la educación postobligatoria. En dicha encrucijada se contemplan también otras variables que se han constatado de gran peso en la toma de decisión como son las notas previas obtenidas, el nivel formativo familiar, el sexo, las expectativas y las aspiraciones, partiendo del modelo decisional de transiciones educativas[1] que contempla el modelo de Boudon sobre los efectos primarios y secundarios. Los resultados obtenidos son los derivad…

Typhetum laxmannii (Ubrizsy 1961) Nedelcu 1968 - The new plant association in Poland

2011

<em>Typhetum laxmannii</em> (Ubrizsy 1961) Nedelcu 1968 is a plant association new to Poland, built by an expansive kenophyte - <em>Typha laxmannii</em> Lepech. This paper presents the general distribution of both, the species and the association, paying particular attention to the area of Europe and Poland where, in recent years, many new locations as well as an increasing participation in vegetation cover have been observed. The habitat preferences of <em>Typhetum laxmannii</em>, the floristic composition of the association and its geographical differentiation within the occupied area are described. The current distribution of the association in Poland …

IMPROVEMENTS IN THE SYSTEMS-BASED MODELS GENERATOR SIGEM

1994

Program generators, for us, are computer programs that produce other computer programs. SIGEM is an expert system program generator that can help in the modeling process of real systems. It is associated with a methodology well adapted to modeling practice. In this paper, we present and compare this methodology with other similar ones. Static models (databases), dynamic models, rule-based expert systems, literal and/or numerical variables, probabilistic uncertainty in data and in functions, dimensioned variables, discrete event simulation, and other related problems can be treated with this methodology. We suggest a systems modeling methodology and a programming tool to increase generality …

Bounded Seed-AGI

2014

Four principal features of autonomous control systems are left both unaddressed and unaddressable by present-day engineering methodologies: (1) The ability to operate effectively in environments that are only partially known at design time; (2) A level of generality that allows a system to re-assess and re-define the fulfillment of its mission in light of unexpected constraints or other unforeseen changes in the environment; (3) The ability to operate effectively in environments of significant complexity; and (4) The ability to degrade gracefully—how it can continue striving to achieve its main goals when resources become scarce, or in light of other expected or unexpected constraining fact…

Time Dependent Deterioration of the X-Ray Dental Diagnostic Equipment

2013

Modern dental X-ray examinations are essential for diagnosis. The goal of this paper is to demonstrate time dependent behavior of dose providing parameters, which help to determine equipment’s age effects on the x-ray machine parameters. Also the comparisons between two different dental X-ray generator equipment types half-period and high frequency was made.

On the generator problem

1990

Design of the CGAL 3D Spherical Kernel and application to arrangements of circles on a sphere

2009

AbstractThis paper presents a cgal kernel for algorithms manipulating 3D spheres, circles, and circular arcs. The paper makes three contributions. First, the mathematics underlying two non-trivial predicates are presented. Second, the design of the kernel concept is developed, and the connexion between the mathematics and this design is established. In particular, we show how two different frameworks can be combined: one for the general setting, and one dedicated to the case where all the objects handled lie on a reference sphere. Finally, an assessment about the efficacy of the 3D Spherical Kernel is made through the calculation of the exact arrangement of circles on a sphere. On average w…