Search results for "descent"
showing 10 items of 99 documents
Transition state theory thermal rate constants and RRKM-based branching ratios for the N((2)D) + CH(4) reaction based on multi-state and multi-refere…
2012
International audience; Multireference single and double configuration interaction (MRCI) calculations including Davidson (+Q) or Pople (+P) corrections have been conducted in this work for the reactants, products, and extrema of the doublet ground state potential energy surface involved in the N(2D) + CH4 reaction. Such highly correlated ab initio calculations are then compared with previous PMP4, CCSD(T), W1, and DFT/B3LYP studies. Large relative differences are observed in particular for the transition state in the entrance channel resolving the disagreement between previous ab initio calculations. We confirm the existence of a small but positive potential barrier (3.86 +/- 0.84 kJ mol-1…
Numerically stable computation of step-sizes for descent methods. The nonconvex case
1977
The computation of step-sizes which guarantee convergence in unconstrained minimization by descent methods is considered. The use of a “control” or “range” function is highly attractive for this purpose because of its simplicity. Since the Armijo-Goldstein test may fail prematurely due to numerical instability near the minimizer, we consider a range function based on gradient values alone as has been done forg convex in [8]. Numerical algorithms are given for the computation of step-sizes whose behaviour under roundoff is shown to be benign in the sense of F. L. Bauer [5].
A robust evolutionary algorithm for the recovery of rational Gielis curves
2013
International audience; Gielis curves (GC) can represent a wide range of shapes and patterns ranging from star shapes to symmetric and asymmetric polygons, and even self intersecting curves. Such patterns appear in natural objects or phenomena, such as flowers, crystals, pollen structures, animals, or even wave propagation. Gielis curves and surfaces are an extension of Lamé curves and surfaces (superquadrics) which have benefited in the last two decades of extensive researches to retrieve their parameters from various data types, such as range images, 2D and 3D point clouds, etc. Unfortunately, the most efficient techniques for superquadrics recovery, based on deterministic methods, cannot…
La industria exógena en la periferia occidental del área metropolitana de Valencia (A.M.V.)
1991
En el tejido industrial de las comarcas occidentales del A. M. V., el Camp de Túria y la Hoya de Buñol-Chiva, hallamos una dualismo respecto al origen de los establecimientos industriales ubicados en ambas comarcas: la industria autóctona y la actividad fabril foránea. Tras analizar los factores que condicionan la localización de estas industrias exógenas definiremos qué rasgos las caracterizan así como el nivel de integración con respecto al espacio que las acoge. En la industria foránea hemos diferenciado aquellos establecimientos industriales que se han instalado tras un traslado de aquéllos otros de nueva creación producto de la iniciativa foránea
RGB Photoelasticity: Review and Improvements
2010
: This paper considers the main developments of RGB photoelasticity with reference to the maximum measurable retardation. In this paper, a new procedure based on the standard error function evaluated on a subset of the calibration array is also proposed and experimentally tested. The experiments show that the filament lamp makes it possible to find retardations until approximately 4 fringe orders while the fluorescent lamp makes it possible to determine higher fringe orders (12 fringe orders in this paper) owing to the discrete spectrum of the source. The paper shows that, by using the incandescent lamp, the primary limiting factor is the lack of modulation of the R, G and B signals wherea…
PERANCANGAN ALAT UKUR INTENSITAS CAHAYA BERBASIS ARDUINO LEONARDO MENGGUNAKAN SENSOR LDR (Light Dependent Resistor)
2020
Lux meter is a device used to measure the intensity of light in an area. The purpose of this thesis is to design a light intensity measuring device using LDR components as a light sensor, comparing light intensity measuring devices made using LDR sensors and Arduino Leonardo based microcontrollers with standard tools. The data used in this study are primary data. The data obtained is then processed using MS. Excel. The type of light bulbs used are Philips CFL (Philips Essential) lamps, each lamp having a power of 5, 8, 11, 14, 18, 23, 27, 32, 35, and 50 watts with a luxmeter vertical distance of 1, 2 and 3 meters from the lamp.
 From the results of testing the tools and processing of c…
Adjoint-based inversion for porosity in shallow reservoirs using pseudo-transient solvers for non-linear hydro-mechanical processes
2020
Abstract Porous flow is of major importance in the shallow subsurface, since it directly impacts on reservoir-scale processes such as waste fluid sequestration or oil and gas exploration. Coupled and non-linear hydro-mechanical processes describe the motion of a low-viscous fluid interacting with a higher viscous porous rock matrix. This two-phase flow may trigger the initiation of solitary waves of porosity, further developing into vertical high-porosity pipes or chimneys. These preferred fluid escape features may lead to localised and fast vertical flow pathways potentially problematic in the case of for instance CO2 sequestration. Constraining the porosity and the non-linearly related pe…
La descoordinación territorial del desarrollo local: ¿demasiados actores para un mismo territorio? Una aproximación empírica a la realidad de la Comu…
2020
La descentralización es en sí mismo un proceso complejo que debe ser planificado, convirtiéndose así en una necesidad para el buen funcionamiento de cualquier modelo. Descentralización en ningún caso significa transferir y olvidarse, sino que cualquier proceso en este sentido necesita de un sistema de coordinación entre todos aquellos actores con implicación en la materia, adecuado al territorio y al contexto, ya que si no puede generar efectos negativos. En el presente texto recogemos algunos de los que están afectando en mayor medida al modelo valenciano para el desarrollo local, así como algunos de sus posibles motivos. Decentralization is in itself a complex process that must be planned…
Large-x Analysis of an Operator-Valued Riemann–Hilbert Problem
2015
International audience; The purpose of this paper is to push forward the theory of operator-valued Riemann-Hilbert problems and demonstrate their effectiveness in respect to the implementation of a non-linear steepest descent method a la Deift-Zhou. In this paper, we demonstrate that the operator-valued Riemann-Hilbert problem arising in the characterization of so-called c-shifted integrable integral operators allows one to extract the large-x asymptotics of the Fredholm determinant associated with such operators.
El alcance de la responsabilidad solidaria prevista en el artículo 42 ET
2020
El artículo 42 ET impone sobre el empresario que contrata o subcontrata con otros la realización de obras o servicios pertenecientes a su propia actividad una responsabilidad solidaria sobre ciertas obligaciones contraídas por el contratista y el subcontratista con sus trabajadores, siempre que hayan nacido durante la vigencia de la contrata. En principio, el significado de la previsión normativa se presenta como relativamente sencillo; no obstante, su aplicación práctica suscita diferentes dudas interpretativas. Pues bien, el objeto de este trabajo se dirige a perfilar el contorno y contenido de la responsabilidad solidaria recogida en el art. 42 ET, lo que exige delimitar con claridad su …