7 results for “fourier transformation”

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Research ArticleOpen accessIn the keywordsNumerical Modeling of Periodic Pumping Tests in Wells Penetrating a Heterogeneous AquiferPeter A. Fokker, Joerg Renner, Francesca VergaThis study investigated how to utilize multiple frequency components of pressure data from periodic pulse tests to estimate the intra-well permeability and compressibility distribution and also the presence of heterogeneities in a real field case. Periodic well testing is a technique in which injection or production pulses of a fluid are applied to a well in a periodic fashion. One … …American Journal of Environmental Sciences, Vol. 9, Issue 1 · 13 Jan 2013 · 7,990 accessesView PDF Cite

Research ArticleOpen accessIn the keywordsOn the Closed Form Solutions of Linear and Nonlinear Cauchy Reaction-Diffusion Equations Using the Hybrid of Fourier Transform and Variational Iteration MethodS.S. Nourazar, A. Nazari-Golshan, M. NourazarProblem statement: In the present study, a hybrid of Fourier transform and Variational Iteration Method (FTVIM) is developed for solving the non-homogeneous linear and nonlinear partial differential equations of Cauchy reaction-diffusion problem. Approach: The closed form solutions obtained from the series solution of recursive sequences is valid for the entire range of problem domain. Results and Conclusion: Moreover, the very … …Physics International, Vol. 2, Issue 1 · 26 Oct 2011 · 8,195 accessesView PDF Cite

Research ArticleOpen accessIn the keywordsImproving the Performance of Multivariate Bernoulli Model based Documents Clustering Algorithms using Transformation TechniquesPerumal Pitchandi, Nedunchezhian RajuProblem statement: Document clustering is the most important areas of data mining since they are very much and currently the subject of significant global research since such areas strengthen the enterprises of web intelligence, web mining, web search engine design and so forth. Generative models based on the multivariate Bernoulli and multinomial distributions have been widely used for text classification. … …Journal of Computer Science, Vol. 7, Issue 5 · 7 May 2011 · 7,281 accessesView PDF Cite

Research ArticleOpen accessIn the abstractThe 'Umbrella' Function Describing the Density of External Electrons Injected in NaCl CrystalSiti Wahyuni, Akrom Khasani, Wipsar Sunu Brams Dwandaru, Muhammad Farchani RosyidElectrons injected in NaCl crystal are studied using Thomas-Fermi-Dirac-von Weizsacker (TFDW) model. The external potential that contributes to the TFDW energy functional is not only due to the nuclei but also to the internal electrons. In order to obtain the potential term due to the internal electrons, the density of the internal electrons in the crystal is derived from the … …American Journal of Applied Sciences, Vol. 13, Issue 12 · 1 Dec 2016 · 8,296 accessesView PDF Cite

Research ArticleOpen accessIn the abstractRetrieval of Similar Shapes Under Affine Transform Using Affine Length ParameterizationA. Lakehal, O. El Beqqali, O. Ait ZemzamiProblem statement: In this study, a new descriptor for shape retrieval under affine transformations had been proposed; the affine length parameterization was used in this approach. Approach: The zero crossing of affine curvature was used to extract a descriptor of shapes in database. For each two successive zero crossing points we extract two parameters: the first parameter was a maximal … …Journal of Computer Science, Vol. 6, Issue 10 · 30 Aug 2010 · 7,255 accessesView PDF Cite

Research ArticleOpen accessIn the abstractAsymptotic Properties of Spectral Estimates of Second-Order with Missed ObservationsG. S. Mokaddis, M. A. Ghazal, A. E. El-DesokeyProblem statement: As a complement of the periodogram study the asymptotic properties of the spectral density using data window for stationary stochastic process are investigated. Some statistical properties of covariance estimation function with missing observations are studied. Approach: The asymptotic normality was discussed. A numerical example was discussed by using computer programming. Results: The study of time series with missed … …Journal of Mathematics and Statistics, Vol. 6, Issue 1 · 31 Mar 2010 · 7,496 accessesView PDF Cite

Research ArticleOpen accessIn the abstractVariable Velocity Influence on the Vibration of Simply Supported Bernoulli - Euler Beam Under Exponentially Varying Magnitude Moving LoadT. O. AwodolaThe variable velocity influence on the vibration of a simply supported Bernoulli-Euler beam, resting on a uniform foundation, under the action of an exponentially varying magnitude load moving with variable velocity is investigated in this work. The technique is based on the Finite Fourier Sine transformation and the Finite Difference method. Numerical results in plotted curves are presented. It is … …Journal of Mathematics and Statistics, Vol. 3, Issue 4 · 31 Dec 2007 · 7,659 accessesView PDF Cite