Antonio Laganà

Computational Science and Its Applications - ICCSA 2006

Lets read! We will often find out this sentence everywhere. When still being a kid, mom used to order us to always read, so did the teacher. Some books are fully read in a week and we need the obligation to support reading. What about now? Do you still love reading? Is reading only for you who have obligation? Absolutely not! We here offer you a new book enPDFd computational science and its applications iccsa 2006 international conference glasgow uk may 8 11 2006 proceedings part iii lecture notes in computer science to read.

Computational Science and Its Applications – ICCSA 2004

Human face detection plays an important role in applications such as video surveillance, human computer interface, face recognition, and face image database management. The face recognition by a CCD camera has the merit of being linked with other recognition systems such as an iris recognition to implement a multimodal recognition system. This paper is concerned with a new approach to face recognition that is automatically distinguished from moving pictures. Based on the research about recognition of color image by a CCD camera, we first find the proper value of color images in order to distinguish the tone of skin from other parts of face. Then, we look for the skin color among the regions of skin color converting RGB into Y , Cb, Cr to find skin parts of face. This new method can be applied to real-time biometric systems. We have developed the approach to face recognition with eigenface, focusing on the effects of eigenface to represent human face under several environment conditions. Finally an error rate is compared when face recognition is processed with facial features through the PCA (principal component analysis).

Supercomputer Algorithms for Reactivity, Dynamics and Kinetics of Small Molecules

Recent Advances in Electronic Structure Theory and their Influence on the Accuracy of Ab initio Potential Energy Surfaces.- Modern Electronic Structure Calculations: The Accurate Prediction of Spectroscopic Band Origins.- Potential Energy Surfaces of Several Elementary Chemical Reactions.- Calculation and Characterization of Reaction Valleys for Chemical Reactions.- Computed Potential Energy Surfaces for Chemical Reactions.- An Ab initio Study on the Coordination of Formaldehyde, Carbon Dioxide, Dinitrogen and Related Molecules to Iron(0) and Nickel(0) Fragments.- Kinetic Paths from the Hyperspherical Perspective: Ab initio Potential Energy Surface for the O(3P)+H2 Reaction.- Exact Quantum Results for Reactive Scattering Using Hyperspherical (APH) Coordinates.- Computational Strategies and Improvements in the Linear Algebraic Variational Approach to Rearrangement Scattering.- How Variational Methods in Scattering Theory Work.- Quantum Dynamics of Small Systems Using Discrete Variable Representations.- Finite Element Calculations of Scattering Matrices for Atom-Diatom Reactive Collisions. Experiences on an Alliant FX/8.- Investigations with the Finite Element Method. The Collinear H + H2, F + H2 and Ne + H2+ Reactions.- Calculation of Multichannel Eigenvalues and Resonances.- Accurate Determination of Polyatomic Infrared Spectra.- The Calculation of Ro-Vibrational Spectra Using Supercomputers.- Approximate Quantum Techniques for Atom Diatom Reactions.- Approximate Quantum Mechanical Calculations on Molecular Energy Transfer and Predissociation.- Temperature-Dependent Rate Constants for Ion-Dipole Reactions: C+(2P) + HCl(X1?+).- Classical Path Approach to Inelastic and Reactive Scattering.- Intramolecular Energy Transfer in HC and HO Overtone Excited Molecules.- Classical Trajectory Studies of Gas Phase Reaction Dynamics and Kinetics Using Ab initio Potential Energy Surfaces.- Quasiclassical Calculations for Alkali and Alkaline Earth + Hydrogen Halide Chemical Reactions Using Supercomputers.- Dynamics of the Light Atom Transfer Reaction: Cl + HCl ? ClH + Cl.- The Modeling of Complex Gas Phase Reactions: From Expert Systems to Supercomputers.

Progress in the non-equilibrium vibrational kinetics of hydrogen in magnetic multicusp H− ion sources

Abstract The non-equilibrium vibrational kinetics of H 2 in multicusp magnetic discharges has been studied by improving a previous model developed by our groups. In particular, a complete set of V-T (vibrational translation) rates involving H-H 2 ( v ) collisions, calculated by using a three-dimensional dynamics approach, has been inserted into our self-consistent model for better representing the corresponding relaxation. Different experimental situations are simulated with special emphasis on the temporal scales necessary for the different distributions (electron energy and vibrational distributions) to reach stationary values. Finally, a comparison between theoretical and experimental quantities such as vibrational temperature, electron temperature, electron number density and concentration of negative ions (H − ) shows a satisfactory agreement, thus indicating the basic correctness of our model.

Decoupling approximations in the quantum mechanical treatment of P‐state atom collisions

Several decoupling schemes are considered, for the effective simplifications of the close coupling equations which arise in the treatment of atomic collisions involving fine structure. Calculations were performed for two models of 2P atoms colliding at thermal energy with a 1S species. From the comparison of exact and approximate results, the relative merits and limits of full or partial decoupling schemes were assessed. Possible improvements and extensions are suggested.

A detailed three‐dimensional quantum study of the Li+FH reaction

Accurate quantum reactive scattering calculations in the full three‐dimensional physical space have been carried out for the Li+FH reaction at zero total angular momentum using the adiabatically adjusting principal axis of inertia hyperspherical coordinate formalism. The procedures for fitting the potential energy surface, calculating the surface functions, and propagating the solutions in a coupled channel treatment are given and discussed. Features of the resulting reactive probability plots are analyzed, and simple explanations of a number of the quantum resonance and oscillatory features are found.

COMPCHEM: Progress Towards GEMS a Grid Empowered Molecular Simulator and Beyond

Foundations and structure of the building blocks of GEMS, the ab initio molecular simulator designed for implementation on the EGEE computing Grid, are analyzed. The impact of the computational characteristics of the codes composing its blocks (the calculation of the ab initio potential energy values, the integration of the dynamics equations of the nuclear motion, and the statistical averaging of microscopic information to evaluate the relevant observable properties) on their Grid implementation when using rigorous ab initio quantum methods are discussed. The requests prompted by this approach for new computational developments are also examined by considering the present implementation of the simulator that is specialized in atom diatom reactive exchange processes.

A comparison of time‐dependent and time‐independent quantum reactive scattering—Li+HF→LiF+H model calculations

Reactive scattering probabilities are computed over a wide range of collision energies for a model system based on the Li+HF→LiF+H reaction using both grid based time‐dependent and time‐independent quantum mechanical methods. The computations are carried out using a fixed Li–F–H angle which is chosen to be that at which the barrier to the chemical reaction is lowest. The calculated reaction probabilities for this system display many sharp features as a function of energy which are ascribed to scattering resonances. The time‐independent calculations have been carried out on a very dense energy grid, thus permitting detailed comparison between time‐independent and time‐dependent methods (in the latter case, a single computation of the wave packet dynamics provides information on the energy dependence over a given energy range). The results show that the time‐dependent calculations are capable of reproducing even the sharpest resonance features computed using the time‐independent method. The time‐dependent techniques are conceptually very simple and therefore easily implemented. The results presented also demonstrate that the grid based time‐dependent quantum mechanical methods used here are able to describe threshold energy dependence of reaction probabilities where the exit channel kinetic energy is effectively zero. The nature of some of the resonance structures are investigated by computing the time‐independent continuum wave functions at the ‘‘resonance’’ energies thus mapping out the nodal structure of the wave functions. The good agreement between time‐independent and time‐dependent methods is shown to be maintained when a centrifugal barrier is added to the potential to simulate the effect of nonzero orbital angular momentum.

On the structuring of the computational chemistry virtual organization COMPCHEM

The first moves to structure the COMPCHEM Grid virtual organization of the computational chemistry community are discussed. A tool based on a credit system developed to guarantee its sustainability is presented.

Hyperspherical adiabatic description of interference effects and resonances in collinear chemical reactions

Abstract Single-channel semiclassical scattering calculations on hyperspherical adiabatic potentials for symmetrical collinear chemical reactions are shown to describe accurately interference effects in reactions such as I + Hi. I + MuI, and resonances in H + MuH. Criteria for the validity of this adiabatic approach, and indications on how to introduce non-adiabatic corrections, are briefly discussed.