The Experts below are selected from a list of 2985 Experts worldwide ranked by ideXlab platform
G L S Bayne - One of the best experts on this subject based on the ideXlab platform.
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tidal flow modelling using a Direct Minimisation method
Coastal Engineering, 1998Co-Authors: G J M Copeland, G L S BayneAbstract:An operational model based on an inverse method is developed for the study of tidal flow in coastal areas. Models based on inverse methods can accommodate large quantities of measured data within the model domain and do not require initial or boundary data in the state variables. These are benefits that overcome the weaknesses in conventional Direct models which can be ill-posed because of inadequate boundary data which cannot make use of extensive survey data. The method described in the paper uses a Direct Minimisation technique, and the governing equations are included as a weak constraint on the solution. This allows the relative influences of data and equations on the final solution to be defined. The model is validated using idealised topographies in terms of data assimilation, flow diversion by topography and tidal flooding and drying over a shoal.
Dimitri Van Neck - One of the best experts on this subject based on the ideXlab platform.
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performance of shannon entropy compacted n electron wave functions for configuration interaction methods
Theoretical Chemistry Accounts, 2016Co-Authors: Diego R Alcoba, Gustavo E Massaccesi, Mario Van Raemdonck, Patrick Bultinck, Luis Lain, Alicia Torre, Paul W Ayers, Dimitri Van NeckAbstract:The coefficients of full configuration interaction wave functions (FCI) for N-electron systems expanded in N-electron Slater determinants depend on the orthonormal one-particle basis chosen although the total energy remains invariant . Some bases result in more compact wave functions, i.e. result in fewer determinants with significant expansion coefficients. In this work, the Shannon entropy, as a measure of information content, is evaluated for such wave functions to examine whether there is a relationship between the FCI Shannon entropy of a given basis and the performance of that basis in truncated CI approaches. The results obtained for a set of randomly picked bases are compared to those obtained using the traditional canonical molecular orbitals, natural orbitals, seniority minimising orbitals and a basis that derives from Direct Minimisation of the Shannon entropy. FCI calculations for selected atomic and molecular systems clearly reflect the influence of the chosen basis. However, it is found that there is no Direct relationship between the entropy computed for each basis and truncated CI energies.
G J M Copeland - One of the best experts on this subject based on the ideXlab platform.
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tidal flow modelling using a Direct Minimisation method
Coastal Engineering, 1998Co-Authors: G J M Copeland, G L S BayneAbstract:An operational model based on an inverse method is developed for the study of tidal flow in coastal areas. Models based on inverse methods can accommodate large quantities of measured data within the model domain and do not require initial or boundary data in the state variables. These are benefits that overcome the weaknesses in conventional Direct models which can be ill-posed because of inadequate boundary data which cannot make use of extensive survey data. The method described in the paper uses a Direct Minimisation technique, and the governing equations are included as a weak constraint on the solution. This allows the relative influences of data and equations on the final solution to be defined. The model is validated using idealised topographies in terms of data assimilation, flow diversion by topography and tidal flooding and drying over a shoal.
Diego R Alcoba - One of the best experts on this subject based on the ideXlab platform.
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performance of shannon entropy compacted n electron wave functions for configuration interaction methods
Theoretical Chemistry Accounts, 2016Co-Authors: Diego R Alcoba, Gustavo E Massaccesi, Mario Van Raemdonck, Patrick Bultinck, Luis Lain, Alicia Torre, Paul W Ayers, Dimitri Van NeckAbstract:The coefficients of full configuration interaction wave functions (FCI) for N-electron systems expanded in N-electron Slater determinants depend on the orthonormal one-particle basis chosen although the total energy remains invariant . Some bases result in more compact wave functions, i.e. result in fewer determinants with significant expansion coefficients. In this work, the Shannon entropy, as a measure of information content, is evaluated for such wave functions to examine whether there is a relationship between the FCI Shannon entropy of a given basis and the performance of that basis in truncated CI approaches. The results obtained for a set of randomly picked bases are compared to those obtained using the traditional canonical molecular orbitals, natural orbitals, seniority minimising orbitals and a basis that derives from Direct Minimisation of the Shannon entropy. FCI calculations for selected atomic and molecular systems clearly reflect the influence of the chosen basis. However, it is found that there is no Direct relationship between the entropy computed for each basis and truncated CI energies.
Gustavo E Massaccesi - One of the best experts on this subject based on the ideXlab platform.
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performance of shannon entropy compacted n electron wave functions for configuration interaction methods
Theoretical Chemistry Accounts, 2016Co-Authors: Diego R Alcoba, Gustavo E Massaccesi, Mario Van Raemdonck, Patrick Bultinck, Luis Lain, Alicia Torre, Paul W Ayers, Dimitri Van NeckAbstract:The coefficients of full configuration interaction wave functions (FCI) for N-electron systems expanded in N-electron Slater determinants depend on the orthonormal one-particle basis chosen although the total energy remains invariant . Some bases result in more compact wave functions, i.e. result in fewer determinants with significant expansion coefficients. In this work, the Shannon entropy, as a measure of information content, is evaluated for such wave functions to examine whether there is a relationship between the FCI Shannon entropy of a given basis and the performance of that basis in truncated CI approaches. The results obtained for a set of randomly picked bases are compared to those obtained using the traditional canonical molecular orbitals, natural orbitals, seniority minimising orbitals and a basis that derives from Direct Minimisation of the Shannon entropy. FCI calculations for selected atomic and molecular systems clearly reflect the influence of the chosen basis. However, it is found that there is no Direct relationship between the entropy computed for each basis and truncated CI energies.