Anàlisi i disseny d'un sistema de còpies de seguretat

Aquest treball presenta el disseny d'un sistema de còpies de seguretat per a una empresa de serveis que presenta dades per a altres empreses. Explica les necessitats de l'empresa i les especificacions que ha de complir el sistema de còpies, i estudia les possibles opcions de programari i maquinari i els aspectes legals.Este trabajo presenta el diseño de un sistema de copias de seguridad para una empresa de servicios que presenta datos para otras empresas. Explica las necesidades de la empresa y las especificaciones que debe cumplir el sistema de copias, y estudia posibles opciones de hardware y software y los aspectos legales.This work presents the design of a backup system for a services company that provides data for other companies. It explains the needs of the company and the specifications that the backup system must comply with, and it studies the possible software and hardware options, in addition to the legal aspects involved

A comparison between experimental and theoretical excitation functions for the O+ + H2 (4A'') system using trajectory calculations over a wide energy range

The O++H2 prototypic ion-molecule reaction was recently studied in our group using the quasiclassical trajectory method on a ground model potential‐energy surface of the system inferred from both experimental and theoretical information and reasonable assumptions, fitted using a London-Eyring-Polanyi-Sato surface modified to include an ion-induced‐dipole interaction term. The theoretical results previously reported agreed rather well with the available experimental information. In view of the latest experimental findings, we present in this contribution the results of new trajectory calculations on the above‐mentioned surface, covering a wide range of relative translational energies of reactants. The accord between the experimental determinations and the present theoretical evaluations is excellent at relative energies below 1.0 eV, while for higher energies the potential‐energy surface, even though still yielding reasonably good results, provides a worse agreement. The observed discrepancies should be attributed either to the too attractive character of the surface or to the interfering influence of the competing O++H2→O+H2+ charge‐transfer process

Dynamics of the N(4Su) + NO(X2Π) → N2(1Σg+) + O(3Pg) atmospheric reaction on the 3A'' ground potential energy surface. I. Analytical potential energy surface and preliminary quasiclassical trajectory calculations

The N(4Su)+NO(X 2Π)→N2(X 1Σg+)+O(3Pg) reaction plays an important role in the upper atmosphere chemistry and as a calibration system for discharge flow systems. Surprisingly, very little theoretical and experimental work has been devoted to the characterization of the dynamical features of this system. In this work a Sorbie-Murrell expression for the lowest 3A' potential energy surface (PES) connecting reactants in their ground electronic states based upon the fitting of an accurate ab initio CI grid of points has been derived. The PES fitted shows no barrier to reaction with respect to the reactants asymptote in accordance with experimental findings and becomes highly repulsive as the NNO angle is varied away from the saddle point geometry. The results of preliminary quasiclassical trajectory calculations on this surface reproduce very well the experimental energy disposal in products, even though the vibrational distribution derived from trajectories seems to be a bit cooler than the experimental data. Moreover, thermal rate constants derived from trajectories are in excellent accordance with experimental values

Dynamics of the N(4S) + NO(X2Π) → N2(X1Σ g+) + O(3P) atmospheric reaction on the 3A'' ground potential energy surface.III. Quantum dynamics study and comparison with quasiclassical and experimental results

A detailed reactive-infinite-order sudden approximation (R-IOSA) study of the reactivity of the N+NO→N2+O system has been carried out in the 0.0038 to 1.388 eV translational energy range and the results have been compared with the existing quasiclassical trajectory (QCT) and experimental data available. The general features already observed in the previous QCT studies are reproduced qualitatively in the quantum study, even though some differences arise in the product vibrational distributions and state-to-state opacity functions in the low energy range. The observed differences have been justified in terms of the anisotropy of the potential energy surface and the vibrational barriers to reaction at fixed angles. A strong vibrational adiabaticity is observed quantally in the low translational energy range, disappearing at moderately high collision energies (around 0.3 eV), where a simple Franck-Condon type model is capable of describing the evolution of the vibrational distribution with translational energy. The vibrational distributions at fixed angles have been discussed within the context of Polanyi's and Light's correlation between products vibrational excitation and the features of the potential energy surface. The validity of extending the conclusions drawn from collinear to three-dimensional (3D) collisions is discussed. Finally, the detailed reaction mechanism is examined in light of the vibrational matrix elements of the close-coupling interaction matrix

Theoretical characterization of transition state dynamical resonances in heavy-light-heavy reactions

The resonant reactivity of three elementary Heavy-Light-Heavy reactions is presented and discussed. Collinear reactivity, in which a vibrational adiabatic model is constructed, is used for a detailed analysis of resonance phenomena, which appear as a direct consequence of transition state metastable states in the strong interaction region of the potential energy surface. Their influence on the detailed mechanism of the elementary process is also discussed. The shape of the resonant peak, and the phase and the Argand plot of the S-matrix are used for a further characterization.Three-dimensional approximate calculations are used to test the evolution of the energy dependent structure present in detailed quantities when sums and integrations over all partial waves contributing to reaction are taken into account to obtain the usual averaged global quantities such as integral state-to-state cross sections

Anàlisi i disseny d'un sistema de còpies de seguretat

Aquest treball presenta el disseny d'un sistema de còpies de seguretat per a una empresa de serveis que presenta dades per a altres empreses. Explica les necessitats de l'empresa i les especificacions que ha de complir el sistema de còpies, i estudia les possibles opcions de programari i maquinari i els aspectes legals.Este trabajo presenta el diseño de un sistema de copias de seguridad para una empresa de servicios que presenta datos para otras empresas. Explica las necesidades de la empresa y las especificaciones que debe cumplir el sistema de copias, y estudia posibles opciones de hardware y software y los aspectos legales.This work presents the design of a backup system for a services company that provides data for other companies. It explains the needs of the company and the specifications that the backup system must comply with, and it studies the possible software and hardware options, in addition to the legal aspects involved

SR-1: A simulation-based algorithm for the Capacitated Vehicle Routing Problem

In this paper we present SR-1, a simulation-based heuristic algorithm for the Capacitated Vehicle Routing Problem (CVRP). Given a CVRP instance, SR-1 uses an initial “good solution”, such as the one provided by the classical Clarke and Wright heuristic, in order to obtain observations for the variable “distance between two consecutive nodes in a route”. These observations are then fitted by a statistical distribution, which characterizes the inter-node distances in good solutions. Then, the fitted distribution is employed to generate a large number of new random solutions with similar edge-size distribution. Thus, a random but oriented local search of the space of solutions is performed, and a list of “best solutions ” is obtained. This list allows considering several properties per solution, not only aprioristic costs, which can be practically used when making multiple-criteria decisions. Several tests have been performed to discuss the effectiveness of this approach.

SR-1: A simulation-based algorithm for the capacitated vehicle routing problem

In this paper we present SR-1, a simulation-based heuristic algorithm for the Capacitated Vehicle Routing Problem (CVRP). Given a CVRP instance, SR-1 uses an initial "good solution", such as the one provided by the classical Clarke and Wright heuristic, in order to obtain observations for the variable "distance between two consecutive nodes in a route". These observations are then fitted by a statistical distribution, which characterizes the inter-node distances in good solutions. Then, the fitted distribution is employed to generate a large number of new random solutions with similar edge-size distribution. Thus, a random but oriented local search of the space of solutions is performed, and a list of "best solutions" is obtained. This list allows considering several properties per solution, not only aprioristic costs, which can be practically used when making multiple-criteria decisions. Several tests have been performed to discuss the effectiveness of this approach

SR-1: A simulation-based algorithm for the capacitated vehicle routing problem

In this paper we present SR-1, a simulation-based heuristic algorithm for the Capacitated Vehicle Routing Problem (CVRP). Given a CVRP instance, SR-1 uses an initial "good solution", such as the one provided by the classical Clarke and Wright heuristic, in order to obtain observations for the variable "distance between two consecutive nodes in a route". These observations are then fitted by a statistical distribution, which characterizes the inter-node distances in good solutions. Then, the fitted distribution is employed to generate a large number of new random solutions with similar edge-size distribution. Thus, a random but oriented local search of the space of solutions is performed, and a list of "best solutions" is obtained. This list allows considering several properties per solution, not only aprioristic costs, which can be practically used when making multiple-criteria decisions. Several tests have been performed to discuss the effectiveness of this approach