5,649 research outputs found

    Incorporating the knowledge management cycle in e-business

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    In e-business, knowledge can be extracted from the recorded information by intelligent data analysis and then utilised in the business transaction. E-knowledge is a foundation for e-business. E-business can be supported by an intelligent information system that provides intelligent business process support and advanced support of the e-knowledge management cycle. Knowledge is stored as knowledge models that can be updated in the e-knowledge management cycle. As illustrated in examples, the e-knowledge cycle aids in the business decision taking, production management, and costs management

    Synthesis and a study of the 13C NMR spectroscopic properties of positional isomers of some C18 acetylenic thia fatty esters

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    The carbon magnetic resonance spectra of four positional acetylenic thia fatty acid methyl ester isomers have been recorded to investigate the effect of the sulfur atom on the chemical shifts of the carbon nuclei adjacent to it.published_or_final_versio

    Search for supersolidity in 4He in low-frequency sound experiments

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    We present results of the search for supersolid 4He using low-frequency, low-level mechanical excitation of a solid sample grown and cooled at fixed volume. We have observed low frequency non-linear resonances that constitute anomalous features. These features, which appear below about 0.8 K, are absent in 3He. The frequency, the amplitude at which the nonlinearity sets in, and the upper temperature limit of existence of these resonances depend markedly on the sample history.Comment: Submitted to the Quantum Fluids and Solids Conf. Aug. 2006 Kyot

    Reduction Operators of Linear Second-Order Parabolic Equations

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    The reduction operators, i.e., the operators of nonclassical (conditional) symmetry, of (1+1)-dimensional second order linear parabolic partial differential equations and all the possible reductions of these equations to ordinary differential ones are exhaustively described. This problem proves to be equivalent, in some sense, to solving the initial equations. The ``no-go'' result is extended to the investigation of point transformations (admissible transformations, equivalence transformations, Lie symmetries) and Lie reductions of the determining equations for the nonclassical symmetries. Transformations linearizing the determining equations are obtained in the general case and under different additional constraints. A nontrivial example illustrating applications of reduction operators to finding exact solutions of equations from the class under consideration is presented. An observed connection between reduction operators and Darboux transformations is discussed.Comment: 31 pages, minor misprints are correcte

    New results on group classification of nonlinear diffusion-convection equations

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    Using a new method and additional (conditional and partial) equivalence transformations, we performed group classification in a class of variable coefficient (1+1)(1+1)-dimensional nonlinear diffusion-convection equations of the general form f(x)ut=(D(u)ux)x+K(u)ux.f(x)u_t=(D(u)u_x)_x+K(u)u_x. We obtain new interesting cases of such equations with the density ff localized in space, which have large invariance algebra. Exact solutions of these equations are constructed. We also consider the problem of investigation of the possible local trasformations for an arbitrary pair of equations from the class under consideration, i.e. of describing all the possible partial equivalence transformations in this class.Comment: LaTeX2e, 19 page

    "Net Protein Utilization Beberapa Formula "Tempe Fish Rice"

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    Angka NPU standar dan operatif makanan campuran TFR dengan pengolahan berbeda telah ditentukan. Angka NPU standar TFR berkisar antara 61-67. Sedangkan angka NPU operatifnya antara 46-57. Bila TFR ditambahkan pada beras dalam perbandingan 1:5 maka NPU berkisar antara 63-66

    Realizations of Real Low-Dimensional Lie Algebras

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    Using a new powerful technique based on the notion of megaideal, we construct a complete set of inequivalent realizations of real Lie algebras of dimension no greater than four in vector fields on a space of an arbitrary (finite) number of variables. Our classification amends and essentially generalizes earlier works on the subject. Known results on classification of low-dimensional real Lie algebras, their automorphisms, differentiations, ideals, subalgebras and realizations are reviewed.Comment: LaTeX2e, 39 pages. Essentially exetended version. Misprints in Appendix are correcte

    Enhanced Group Analysis and Exact Solutions of Variable Coefficient Semilinear Diffusion Equations with a Power Source

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    A new approach to group classification problems and more general investigations on transformational properties of classes of differential equations is proposed. It is based on mappings between classes of differential equations, generated by families of point transformations. A class of variable coefficient (1+1)-dimensional semilinear reaction-diffusion equations of the general form f(x)ut=(g(x)ux)x+h(x)umf(x)u_t=(g(x)u_x)_x+h(x)u^m (m0,1m\ne0,1) is studied from the symmetry point of view in the framework of the approach proposed. The singular subclass of the equations with m=2m=2 is singled out. The group classifications of the entire class, the singular subclass and their images are performed with respect to both the corresponding (generalized extended) equivalence groups and all point transformations. The set of admissible transformations of the imaged class is exhaustively described in the general case m2m\ne2. The procedure of classification of nonclassical symmetries, which involves mappings between classes of differential equations, is discussed. Wide families of new exact solutions are also constructed for equations from the classes under consideration by the classical method of Lie reductions and by generation of new solutions from known ones for other equations with point transformations of different kinds (such as additional equivalence transformations and mappings between classes of equations).Comment: 40 pages, this is version published in Acta Applicanda Mathematica
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