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N. A. Mershchikova - One of the best experts on this subject based on the ideXlab platform.

  • Bimodal quasi-one-Dimensional Method for the inverse problem of marine electromagnetic sounding
    Computational Mathematics and Modeling, 2012
    Co-Authors: N. I. Berezina, V. I. Dmitriev, N. A. Mershchikova
    Abstract:

    In this article we apply the quasi-one-Dimensional Method proposed in [1] to solve inverse problems in marine electromagnetic sounding with the field measured at the seabed. The electromagnetic field source is a plane wave and observations are made for two electromagnetic field polarizations. The structure of the medium as commonly modeled in marine sounding contains a highly conducting top layer representing the sea. The set of models for which numerical computations have been carried out include a two-Dimensional two-layer medium with a nonhomogeneous body in the second layer. The sea is modeled by a conducting top layer of constant thickness; the conductivity of the second layer is an order of magnitude lower. The conductivity of the embedded nonhomogeneous body is one to two orders of magnitude lower than the conductivity of the second layer. The electromagnetic field is observed at the lower boundary of the conducting top layer modeling the sea. The two-Dimensional bimodal inversion Method proposed in [2–3] interprets the sounding data in quasitwo-Dimensional media by simultaneously observing a plane electromagnetic field in two polarizations. In these studies the bimodal inversion Method is applied in inverse problems associated with depth magnetotelluric sounding. In the present article the effect of simultaneous observations of two field polarizations is investigated in inverse problems for typical marine sounding models. The inverse problems are solved numerically by the quasi-one-Dimensional iteration Method [1], which exploits the properties of the electromagnetic field propagating in conducting quasi-layered media. For a quasilayered model, the field value at every observation point on the profile may be assumed equal, in the first approximation, to the field value computed for a locally one-Dimensional layered medium obtained when a section perpendicular to the profile is passed at the observation point. This technique can reduce the computational effort to solve the inverse problem if for most iterations we replace the numerical solution of the full twoDimensional direct problem with the solution of a series of one-Dimensional direct problems.

  • Bimodal quasi-one-Dimensional Method for the inverse problem of marine electromagnetic sounding
    Computational Mathematics and Modeling, 2012
    Co-Authors: N. I. Berezina, V. I. Dmitriev, N. A. Mershchikova
    Abstract:

    A quasi-one-Dimensional Method is applied to solve two-Dimensional inverse problems with a plane wave source and observations for two electromagnetic field polarizations. The structure of the medium is represented by a model commonly used in marine sounding, with the electromagnetic field observed at the lower boundary of a conducting top layer modeling the sea.

  • Quasi-one-Dimensional Method for the two-Dimensional inverse problem of magnetotelluric sounding
    Computational Mathematics and Modeling, 2011
    Co-Authors: N. I. Berezina, V. I. Dmitriev, N. A. Mershchikova
    Abstract:

    The article presents a quasi-one-Dimensional Method for solving the inverse problem of electromagnetic sounding. The quasi-one-Dimensional Method is an iteration process that in each iteration solves a parametric one-Dimensional inverse problem and a two-Dimensional direct problem. The solution results of these problems are applied to update the input values for the parametric one-Dimensional inverse problem in the next iteration. The Method has been implemented for a two-Dimensional inverse problem of magnetotelluric sounding in a quasi-layered medium.

V. I. Dmitriev - One of the best experts on this subject based on the ideXlab platform.

  • Bimodal quasi-one-Dimensional Method for the inverse problem of marine electromagnetic sounding
    Computational Mathematics and Modeling, 2012
    Co-Authors: N. I. Berezina, V. I. Dmitriev, N. A. Mershchikova
    Abstract:

    In this article we apply the quasi-one-Dimensional Method proposed in [1] to solve inverse problems in marine electromagnetic sounding with the field measured at the seabed. The electromagnetic field source is a plane wave and observations are made for two electromagnetic field polarizations. The structure of the medium as commonly modeled in marine sounding contains a highly conducting top layer representing the sea. The set of models for which numerical computations have been carried out include a two-Dimensional two-layer medium with a nonhomogeneous body in the second layer. The sea is modeled by a conducting top layer of constant thickness; the conductivity of the second layer is an order of magnitude lower. The conductivity of the embedded nonhomogeneous body is one to two orders of magnitude lower than the conductivity of the second layer. The electromagnetic field is observed at the lower boundary of the conducting top layer modeling the sea. The two-Dimensional bimodal inversion Method proposed in [2–3] interprets the sounding data in quasitwo-Dimensional media by simultaneously observing a plane electromagnetic field in two polarizations. In these studies the bimodal inversion Method is applied in inverse problems associated with depth magnetotelluric sounding. In the present article the effect of simultaneous observations of two field polarizations is investigated in inverse problems for typical marine sounding models. The inverse problems are solved numerically by the quasi-one-Dimensional iteration Method [1], which exploits the properties of the electromagnetic field propagating in conducting quasi-layered media. For a quasilayered model, the field value at every observation point on the profile may be assumed equal, in the first approximation, to the field value computed for a locally one-Dimensional layered medium obtained when a section perpendicular to the profile is passed at the observation point. This technique can reduce the computational effort to solve the inverse problem if for most iterations we replace the numerical solution of the full twoDimensional direct problem with the solution of a series of one-Dimensional direct problems.

  • Bimodal quasi-one-Dimensional Method for the inverse problem of marine electromagnetic sounding
    Computational Mathematics and Modeling, 2012
    Co-Authors: N. I. Berezina, V. I. Dmitriev, N. A. Mershchikova
    Abstract:

    A quasi-one-Dimensional Method is applied to solve two-Dimensional inverse problems with a plane wave source and observations for two electromagnetic field polarizations. The structure of the medium is represented by a model commonly used in marine sounding, with the electromagnetic field observed at the lower boundary of a conducting top layer modeling the sea.

  • Quasi-one-Dimensional Method for the two-Dimensional inverse problem of magnetotelluric sounding
    Computational Mathematics and Modeling, 2011
    Co-Authors: N. I. Berezina, V. I. Dmitriev, N. A. Mershchikova
    Abstract:

    The article presents a quasi-one-Dimensional Method for solving the inverse problem of electromagnetic sounding. The quasi-one-Dimensional Method is an iteration process that in each iteration solves a parametric one-Dimensional inverse problem and a two-Dimensional direct problem. The solution results of these problems are applied to update the input values for the parametric one-Dimensional inverse problem in the next iteration. The Method has been implemented for a two-Dimensional inverse problem of magnetotelluric sounding in a quasi-layered medium.

  • Quasi-one-Dimensional Method for the two-Dimensional magnetotelluric sounding inverse problem
    Computational Mathematics and Modeling, 2006
    Co-Authors: P. S. Belkin, V. I. Dmitriev
    Abstract:

    The two-Dimensional magnetotelluric sounding inverse problem is solved by a quasi-one-Dimensional Method. A linearization Method is proposed for one-Dimensional inverse problems. The appearance of false conducting structures in the solution of the inverse problem is considered and some counter-measures are suggested. The quasi-one-Dimensional Method is applicable to many-Dimensional magnetotelluric sounding inverse problems if the electrical conductivity is a priori known to vary slowly along the Earth’s surface.

N. I. Berezina - One of the best experts on this subject based on the ideXlab platform.

  • Bimodal quasi-one-Dimensional Method for the inverse problem of marine electromagnetic sounding
    Computational Mathematics and Modeling, 2012
    Co-Authors: N. I. Berezina, V. I. Dmitriev, N. A. Mershchikova
    Abstract:

    In this article we apply the quasi-one-Dimensional Method proposed in [1] to solve inverse problems in marine electromagnetic sounding with the field measured at the seabed. The electromagnetic field source is a plane wave and observations are made for two electromagnetic field polarizations. The structure of the medium as commonly modeled in marine sounding contains a highly conducting top layer representing the sea. The set of models for which numerical computations have been carried out include a two-Dimensional two-layer medium with a nonhomogeneous body in the second layer. The sea is modeled by a conducting top layer of constant thickness; the conductivity of the second layer is an order of magnitude lower. The conductivity of the embedded nonhomogeneous body is one to two orders of magnitude lower than the conductivity of the second layer. The electromagnetic field is observed at the lower boundary of the conducting top layer modeling the sea. The two-Dimensional bimodal inversion Method proposed in [2–3] interprets the sounding data in quasitwo-Dimensional media by simultaneously observing a plane electromagnetic field in two polarizations. In these studies the bimodal inversion Method is applied in inverse problems associated with depth magnetotelluric sounding. In the present article the effect of simultaneous observations of two field polarizations is investigated in inverse problems for typical marine sounding models. The inverse problems are solved numerically by the quasi-one-Dimensional iteration Method [1], which exploits the properties of the electromagnetic field propagating in conducting quasi-layered media. For a quasilayered model, the field value at every observation point on the profile may be assumed equal, in the first approximation, to the field value computed for a locally one-Dimensional layered medium obtained when a section perpendicular to the profile is passed at the observation point. This technique can reduce the computational effort to solve the inverse problem if for most iterations we replace the numerical solution of the full twoDimensional direct problem with the solution of a series of one-Dimensional direct problems.

  • Bimodal quasi-one-Dimensional Method for the inverse problem of marine electromagnetic sounding
    Computational Mathematics and Modeling, 2012
    Co-Authors: N. I. Berezina, V. I. Dmitriev, N. A. Mershchikova
    Abstract:

    A quasi-one-Dimensional Method is applied to solve two-Dimensional inverse problems with a plane wave source and observations for two electromagnetic field polarizations. The structure of the medium is represented by a model commonly used in marine sounding, with the electromagnetic field observed at the lower boundary of a conducting top layer modeling the sea.

  • Quasi-one-Dimensional Method for the two-Dimensional inverse problem of magnetotelluric sounding
    Computational Mathematics and Modeling, 2011
    Co-Authors: N. I. Berezina, V. I. Dmitriev, N. A. Mershchikova
    Abstract:

    The article presents a quasi-one-Dimensional Method for solving the inverse problem of electromagnetic sounding. The quasi-one-Dimensional Method is an iteration process that in each iteration solves a parametric one-Dimensional inverse problem and a two-Dimensional direct problem. The solution results of these problems are applied to update the input values for the parametric one-Dimensional inverse problem in the next iteration. The Method has been implemented for a two-Dimensional inverse problem of magnetotelluric sounding in a quasi-layered medium.

Fang Wang - One of the best experts on this subject based on the ideXlab platform.

  • Research on the gas-holdup measurement of gas-liquid two-phase flow based on the dynamical differential pressure signals of multi-loop meter
    Chinese Journal of Sensors and Actuators, 2007
    Co-Authors: Fang Wang, G.-w. Liang, D.-l. Xie
    Abstract:

    A new multi-loop flow sensor is designed for the parameters measurement of gas-liquid two-phase flow. The dynamical differential pressure signals of gas-liquid two-phase flow collected from the rising section at the horizontal diameter of the multi-loop sensor are analyzed. A characteristic value related to the variance of the dynamical differential pressure signals is obtained. The relationship between the characteristic value of differential pressures and the volumetric void fraction is established. The gas density is introduced for the correction of this mode. The experiments were carried out on the horizontal multi-phase flow loop. The non-Dimensional Method was applied to analyze the data. The relationship between the volumetric void fraction and the non-Dimensional value are achieved. The online measurement of the volumetric void fraction of gas-liquid two-phase is realized through the multi-loop flow sensor. The experimental results showed that the determination error of the measurement of volumetric void fraction can be limited within 5%, when the actual volumetric void fractions were less than 0.65.

  • Analysis on dynamic differential pressures of multi-loop flowmeter for the measurement of gas-liquid two-phase flow
    AIP Conference Proceedings, 2007
    Co-Authors: Dailiang Xie, Guowei Liang, Fang Wang
    Abstract:

    A multi-loop flow sensor with new structure is designed for the parameters measurement of gas-liquid two-phase flow. The dynamical differential pressure signals of gas-liquid two-phase flow captured from the rising section at the horizontal diameter of the multi-loop sensor are analyzed. A characteristic value related to the root-mean-square of the dynamical differential pressure signals is obtained. The relationship between the characteristic value of differential pressures and the volumetric void fraction is established. The gas density is introduced for the correction of this mode. The experiments were carried out on the horizontal multi-phase flow loop. The non-Dimensional Method was applied to analyze the data. The relationship between the volumetric void fraction and the non-Dimensional value are achieved. The online measurement of the volumetric void fraction of gas-liquid two-phase is realized through the multi-loop flow sensor. The experiments showed that the results are satisfactory. © 2007 American Institute of Physics.

C. Van Den Berg - One of the best experts on this subject based on the ideXlab platform.

  • A QUANTITATIVE, THREE-Dimensional Method FOR ANALYZING ROTATIONAL MOVEMENT FROM SINGLE-VIEW MOVIES
    The Journal of Experimental Biology, 1994
    Co-Authors: C. Van Den Berg
    Abstract:

    The study of animal movement is an important aspect of functional morphological research. The three-Dimensional movements of (parts of) animals are usually recorded on two-Dimensional film frames. For a quantitative analysis, the real movements should be reconstructed from their projections. If movements occur in one plane, their projection is distorted only if this plane is not parallel to the film plane. Provided that the parallel orientation of the movement with respect to the film plane is checked accurately, a two-Dimensional Method of analysis (ignoring projection errors) can be justified for quantitative analysis of planar movements. Films of movements of skeletal elements of the fish head have generally been analyzed with the two-Dimensional Method (e.g. Sibbing, 1982; Hoogenboezem et al. 1990; Westneat, 1990; Claes and de Vree, 1991), which is justifiable for planar movements. Unfortunately, the movements of the head bones of fish are often strongly non-planar, e.g. the movement of the pharyngeal jaws and the gill arches. The two-Dimensional Method is inappropriate for studying such complex movements (Sibbing, 1982; Hoogenboezem et al. 1990). For a qualitative description of movement patterns, the conditions for the use of the two-Dimensional Method may be somewhat relaxed. When two (or more) views of a movement are recorded simultaneously, the three-Dimensional movements can readily be reconstructed using two two-Dimensional images (e.g. Zarnack, 1972; Nachtigall, 1983; van Leeuwen, 1984; Drost and van den Boogaart, 1986). However, because of technical (and budget) limitations, simultaneous views of a movement cannot always be shot. In this paper, a Method is presented for reconstructing the three-Dimensional orientation and rotational movement of structures using single-view films and for calculating rotation in an object-bound frame. Ellington (1984) presented a similar Method for determining three-Dimensional wing movements from single-view films of flying insects. Ellington9s Method is based upon the bilateral symmetry of the wing movements. The present Method does not depend on symmetry and can be applied to a variety of kinematic investigations. It eliminates a systematic error: the projection error. The measuring error is not discussed; it is the same in the two-Dimensional and three-Dimensional Method of analysis.

  • SHORT COMMUNICATION A QUANTITATIVE, THREE-Dimensional Method FOR ANALYZING ROTATIONAL MOVEMENT FROM SINGLE-VIEW MOVIES
    1994
    Co-Authors: C. Van Den Berg
    Abstract:

    The study of animal movement is an important aspect of functional morphological research. The three-Dimensional movements of (parts of) animals are usually recorded on two-Dimensional film frames. For a quantitative analysis, the real movements should be reconstructed from their projections. If movements occur in one plane, their projection is distorted only if this plane is not parallel to the film plane. Provided that the parallel orientation of the movement with respect to the film plane is checked accurately, a twoDimensional Method of analysis (ignoring projection errors) can be justified for quantitative analysis of planar movements. Films of movements of skeletal elements of the fish head have generally been analyzed with the two-Dimensional Method (e.g. Sibbing, 1982; Hoogenboezem et al. 1990; Westneat, 1990; Claes and de Vree, 1991), which is justifiable for planar movements. Unfortunately, the movements of the head bones of fish are often strongly non-planar, e.g. the movement of the pharyngeal jaws and the gill arches. The two-Dimensional Method is inappropriate for studying such complex movements (Sibbing, 1982; Hoogenboezem et al. 1990). For a qualitative description of movement patterns, the conditions for the use of the two-Dimensional Method may be somewhat relaxed. When two (or more) views of a movement are recorded simultaneously, the threeDimensional movements can readily be reconstructed using two two-Dimensional images (e.g. Zarnack, 1972; Nachtigall, 1983; van Leeuwen, 1984; Drost and van den Boogaart, 1986). However, because of technical (and budget) limitations, simultaneous views of a movement cannot always be shot. In this paper, a Method is presented for reconstructing the three-Dimensional orientation and rotational movement of structures using singleview films and for calculating rotation in an object-bound frame. Ellington (1984) presented a similar Method for determining three-Dimensional wing movements from single-view films of flying insects. Ellington’s Method is based upon the bilateral symmetry of the wing movements. The present Method does not depend on symmetry and can be applied to a variety of kinematic investigations. It eliminates a systematic error: the projection error. The measuring error is not discussed; it is the same in the twoDimensional and three-Dimensional Method of analysis.