Two approaches for directly computing a molecular heat of formation based on sophisticated ab initio

The solution method is a type of successive order of scattering approach or Picard iteration. The model computes accurate radiances or fluxes in either the ...

Two main approaches are available for the rational design of networks, the statistical and the experimental. The statistical approach presupposes the ability to compute accurate correlation functions of the meteorological fields to be observed and analyze...

Petascale computing helps disentangle the nuclear puzzle. The goal of the UNEDF collaboration is to provide a comprehensive description of all nuclei and their reactions based on the most accurate knowledge of the nuclear interaction, the most reliable theoretical approaches, and the massive use of the computer ...

To more accurately treat severe accidents in fast reactors, a program has been set up to investigate new computational models and approaches. The product of this effort is a computer code, the Advanced Fluid Dynamics Model (AFDM). This paper describes som...

May 5, 2010 ... On the other hand, they need to cope with external ... how our approach can be generalised to a hierarchy of increasingly accurate ...... Computers and Intractability: A Guide to the Theory of NP-Completeness. ...

A recent report by Brown (1973) initiated a new approach to satellite altimetry adjustment, in the sense that highly accurate reference orbits are no longer required. Computer simulations indicated that in this way, global oceanic geoid accurate to within...

Two continuing and important objectives of computational chemists and chemical engineers are first, to predict accurately the feasibility and extent of chemical reactions, and second, to predict accurately the rate of approach to chemical equilibrium for ...

We have developed a new approach to accurately calculate entropy change based on density functional theory in the energy representation. The entropy change was evaluated using the derived equation and energy distributions computed using molecular simulation and reweighting techniques. This approach was applied to a ...

We review the current status of Waterman's T-matrix approach which is one of the most powerful and widely used tools for accurately computing light ...

Treatment planning in proton therapy requires the calculation of absorbed dose distributions on beam shaping components and the patient anatomy. Analytical pencil-beam dose algorithms commonly used are not always accurate enough. The Monte Carlo approach is more accurate but extremely computationally intensive. The ...

A technique is proposed for computing the field radiated from a rectangular aperture. This technique, based on the discrete fractional Fourier transform, avoids the complexities of computing the diffraction pattern by the direct evaluation of the Fresnel integral. The advocated approach provides a fast and accurate ...

Scientific codes are usually parallelized by partitioning a grid among processors. To achieve top performance it is necessary to partition the grid so as to balance workload and minimize communication/synchronization costs. This problem is particularly acute when the grid is irregular, changes over the course of the computation, and is not known until load time. Critical ...

This paper presents an efficient method of generation capacity reliability evaluation including the effect of planned outages. The conventional approach to this problem is to compute weekly indices and aggregate them to obtain the annual indices. The proposed approach develops a composite load model for the year in which the effect of ...

A high-degree spherical harmonic series is used to compute the radial deformation of the Earth by oceanic tidal loading. By exploiting fast numerical transforms, this approach is found to be much more efficient, but no less accurate, than the traditional ...

Many problems in computer applications can in theory be solved by searching through a directed-acyclic graph (DAG). In practice, however, this approach has been hampered by our analytical inability to predict the search cost accurately without actually im...

An international panel has suggested that global warming has arrived but many scientist say it will be a decade before computer models can confidently link the warming to human activities. This article describes the major problems with global climate change models and different approaches to developing a more accurate model.

The traditional approach to the design of engine inlets for commercial transport aircraft is a tedious process that ends with a less-than-optimum design. With the advent of high-speed computers and the availability of more accurate and reliable computatio...

Preoperative localization of the aortic arch is important in infants with esophageal atresia to prevent morbidity and death from an ipsilateral surgical approach. Computed tomography is an accurate, noninvasive technique for determining the position of the aortic arch.

Temperature and size considerations of the tube fin space radiator were characterized by charts and equations. An approach of accurately assessing rejection capability commensurate with a phase A/B level output is reviewed. A computer program, based on Ma...

performance. They've got a handle on their costs and consequently are able to more accurately predict on many levels--from comprehensive outsourcing and application management to hosting and utility computing the on demand tenets of a holistic approach, horizontal integration, and IT outsourcing and standardization

A new approach to quantitative deformation characterization of high-resolution electron microscopy (HREM) defect images has been developed. The principle of this technique, (Computational Fourier Transform Deformation (CFTD)) is to extract an accurate dis...

The work done in this paper is based on our earlier work on developing an extended Miedema model and then using it to downselect potential alloy systems. Our approach is to closely couple the semi-empirical methodologies to more accurate ab initio methods...

We propose an efficient, accurate method to integrate the basins of attraction of a smooth function defined on a general discrete grid and apply it to the Bader charge partitioning for the electron charge density. Starting with the evolution of trajectories in space following the gradient of charge density, we derive an expression for the fraction of space neighboring each ...

We describe a perturbation formulation for the problem of computing electrostatic capacitances of multiple conductors embedded in multiple dielectric materials. Unlike the commonly used equivalent-charge formulation (ECF), this new approach insures that the capacitances are computed accurately even when the ...

Page 1. EFFICIENT AND ACCURATE COMPUTATION OF NON-NEGATIVE ANISOTROPIC SCATTERING CROSS SECTIONS ...

An accurate computational method for the one-dimensional quantum Hamilton-Jacobi equation is presented. The Mobius propagation scheme, which can accurately pass through singularities, is used to numerically integrate the quantum Hamilton-Jacobi equation for the quantum momentum function. Bound state wave functions are then synthesized ...

An accurate computational method for the one-dimensional quantum Hamilton-Jacobi equation is presented. The Moebius propagation scheme, which can accurately pass through singularities, is used to numerically integrate the quantum Hamilton-Jacobi equation for the quantum momentum function. Bound state wave functions are then synthesized ...

A new approach for computing calcite scaling tendencies is described. Computed values are obtained by exactly solving the chemical equilibria expressions for calcite precipitation. To date, extremely accurate predictions of calcite scale deposition in oilfield systems have been made based on this ...

For a system of coupled anharmonic oscillators we compare the convergence rate of the variational collocation approach presented recently by Amore and Fern�ndez (2010 Phys. Scr. 81 045011) with the one obtained using the optimized Rayleigh�Ritz (RR) method. The monotonic convergence of the RR method allows us to obtain more accurate results at a lower ...

Radar simulation involves the computation of a radar response based on the terrain's normalized radar cross section (RCS). In the past different models have been proposed for modeling the normalized RCS. While being accurate in most cases they lack intuitive handling. We present a novel approach for computing the ...

A simple and accurate dispatch method to economically schedule large power system generations is presented and tested. The proposed method is based on a piecewise active reactive network loss model and is more accurate than the classical approach for different system load levels. The method can be superior to optimal load flow methods ...

We present a method, CamShift, for the rapid and accurate prediction of NMR chemical shifts from protein structures. The calculations performed by CamShift are based on an approximate expression of the chemical shifts in terms of polynomial functions of interatomic distances. Since these functions are very fast to compute and readily differentiable, the ...

An approach to the construction of high-order accurate implicit predictor-corrector schemes is proposed. The accuracy is improved by choosing a special time integration step for computing numerical fluxes through cell interfaces by using an unconditionally stable implicit scheme. For smooth solutions of advection equations with ...

Treatment planning in proton therapy requires the calculation of absorbed dose distributions on beam shaping components and the patient anatomy. Analytical pencil-beam dose algorithms commonly used are not always accurate enough. The Monte Carlo approach is more accurate but extremely computationally intensive. The ...

The approximation error approach has been earlier proposed to handle modelling, numerical and computational errors in inverse problems. The idea of the approach is to include the errors to the forward model and compute the approximate statistics of the errors using Monte Carlo sampling. This can be a ...

Computational models that reproduce and predict the detailed behavior of cellular systems form the Holy Grail of systems biology [1]. Molecular Dynamics represents the most accurate and fundamental approach to cell simulation, taking into account the fundamental physical rules at the atomic level. Due to the incredible high number of ...

Recent advances in fixed appliances are reviewed and discussed. These include cosmetically more appealing brackets (ceramic, lingual); new wires (nickel-titanium and titanium-molybdenum alloys); new biomechanical approaches (accurate computation of forces and torques according to Burstone resulting in the use of new mechanical ...

The well-established Abbe formulation is one of today's most common approaches for the accurate image simulation of partial coherent projection systems used in semiconductor lithography. The development and application of lithographic imaging systems close to the theoretical resolution limits and the desire for the simulation of larger mask areas with high ...

Mean-Field homogenization algorithms for materials involving two or more elastic-plastic constituent phases are investigated. The Voigt, Reuss and Self consistent schemes which are directly applicable to multi-phase systems are implemented. The shortcomings of these schemes are accuracy for the former two and computational efficiency for the latter. A new interpolative model ...

For Computation of fluid-solid interfaces, which is one of the most challenging classes of problems in computational engineering and sciences, has been receiving much attention in recent years. The numerical challenges include (i) accurate representation of the flow field near the interface, (ii) accurate advection ...

A computational study of microinstabilities in general geometry is presented. The ion gyrokinetic is solved as an initial value problem. The advantage of this approach is the accurate treatment of some important kinetic effects. The magnetohydrodynamic equilibrium is obtained from a three-dimensional local equilibrium model. The use of ...

A DNA computing algorithm (DNACA) with an electron-ion interaction potential (EIIP) decoding scheme is proposed to identify a class of transfer functions. The DNACA includes enzyme and virus operators which provide a highly modular, flexible, and accurate self-organizing structure environment. Simulation study based on De Jong's test functions show its ...

Accurate alignment and focus of mirror facets are critical for the integration of concentrators and receivers in many of the low-cost stretched-membrane concentrators currently under development. In this report, the theoretical development of computer software that traces light rays from a source to a facet of a point-focusing solar concentrator and then ...

A linear scaling approach for general and accurate pseudopotential Density Functional Theory calculations is presented. It is based on a Finite Difference discretization. Effective O(N) scaling is achieved by confining the orbitals in spherical localization regions. To improve accuracy and flexibility while computing the smallest ...

Inverse problem solutions in NDE can be broadly classified as model-based approach and system-based approach. In model-based approach an accurate forward model is used in an iterative framework to provide a defect shape that minimizes the error between the measured signal and a simulated signal. However this ...

An approach to multi-dimensional quadrature, designed to exploit parallel architectures, is described. This involves transforming the integral in such a way that an accurate result is given by the trapezoidal rule; and by evaluating the resulting sum in a manner which may be efficiently implemented on parallel architectures. This ...

A quantum dynamics approach, called Gaussian molecular dynamics, is introduced. As in the centroid molecular dynamics, the N-body quantum system is mapped to an N-body classical system with an effective Hamiltonian arising within the variational Gaussian wave-packet approximation. The approach is exact for the harmonic oscillator and for the ...

The Lagrange functions are a family of analytical, complete, and orthonormal basis sets that are suitable for efficient, accurate, real-space, order-N electronic-structure calculations. Convergence is controlled by a single monotonic parameter, the dimension of the basis set, and computational complexity is lower than that of conventional ...

An approach to Witten string field theory based on the discretization of the world sheet is adopted. We use it to calculate tree amplitudes with the formulation of the theory based on string functionals. The results are evaluated numerically and turn out to be very accurate, giving, for a string approximated by 600 points, values within 0.02% of the ...

This paper presents an accurate and very robust least squares collocation technique that allows one to employ the preconditioned conjugate gradient solution procedure and orthogonal meshes to the solution of the advection diffusion equation defined over domains with irregular shape. The new approach can achieve a reasonable fraction of the optimal ...

This paper describes an algorithm for generating unit planned outage modeling in the extended decomposition-simulation approach for multi-area reliability calculations. A brief description of the extended decomposition-simulation approach is presented. Then, the algorithm for generating unit planned outage modeling is described. The algorithm is based on a ...

A new approach for computing the atom-in-molecule [quantum theory of atoms in molecule (QTAIM)] energies in Kohn-Sham density-functional theory is presented and tested by computing QTAIM energies for a set of representative molecules. In the new approach, the contribution for the correlation-kinetic energy (T(c)) ...

A new approach for computing the atom-in-molecule [quantum theory of atoms in molecule (QTAIM)] energies in Kohn-Sham density-functional theory is presented and tested by computing QTAIM energies for a set of representative molecules. In the new approach, the contribution for the correlation-kinetic energy (Tc) is ...