Begell House Inc.
Telecommunications and Radio Engineering
TRE
0040-2508
56
6&7
2001
From Editor
1
10.1615/TelecomRadEng.v56.i6-7.10
This issue is a continuation of our publications based on reports presented at the First International Workshop on Mathematical Modeling of Physical Processes in Inhomogeneous Media (20−22 March 2001, Guanajuato, Mexico) and not included in the special issue of the journal "Telecommunications and Radio Engineering" (no. 4−5). These works of Russian and Mexican scientists are dedicated to problems of mathematical modeling, mathematical physics, and signal processing. New ideas and results may find applications in solving the wide class of theoretical and practical problems.
Atomic-fractal Functions in Problems of Antenna Synthesis
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10.1615/TelecomRadEng.v56.i6-7.20
Victor Filippovich
Kravchenko
Kotelnikov Institute of Radio Engineering and Electronics, Russian Academy of Sciences, 11-7, Mokhovaya St., Moscow 125009, Russia; Bauman Moscow State Technical University, 5, Vtoraya Baumanskaya St., Moscow 105005 Russia; Scientific and Technological Center of Unique Instrumentation, Russian Academy of Sciences, 15, Butlerova St., Moscow 117342, Russia
Aleksander Alekseevich
Potapov
Leading Researcher at the IRE of the RAS, Russia
Vladimir Mikhailovich
Masyuk
Post-graduate student at the Chair "Higher Mathematics " of the Bauman MSTU, Russia
ABSTRACT: Foundations of measure theory, the Hausdorff-Besicovitch measure, fractal nowhere differentiable Boltzano, Van-der-Waerden, and Besicovitch functions, and also some atomic functions possessing fractal properties are considered. For the first time, the atomic-fractal functions are constructed. The theory proposed and justified is illustrated on problems of synthesis of fractal radiating structures by means of modeling the corresponding physical processes.
Solving the Wave Equation for a Slotted Cone Placed on an Impedance Plane
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10.1615/TelecomRadEng.v56.i6-7.30
V. A.
Doroshenko
Kharkiv National University of Radio Engineering and Electronics, 14, Nauka Ave, Kharkiv, 61166, Ukraine
Modeling a problem of nonstationary electromagnetic wave diffraction on an infinite circular slotted cone placed on an impedance plane is considered. The solution method is based on using the Laplace inversion, the Kontorovich-Lebedev transforms, and the Riemann-Hilbert method. Representations for the Green's function are obtained.
Propagation of Eigen Electromagnetic Wave in an Irregular Impedance Waveguide
8
10.1615/TelecomRadEng.v56.i6-7.40
V. L.
Pazynin
O.Ya. Usikov Institute for Radio Physics and Electronics,
National Academy of Sciences of Ukraine
12, Academician Proskura St., Kharkiv 61085, Ukraine
The problem is considered on propagation of the electromagnetic TH-wave in a planar waveguide with perfectly conductive upper wall and with lower wall having finite conductivity changed as th τx. An analytical solution of this problem has been derived and the limiting cases have been analyzed.
Methods for Solving Problems of Antennas Analysis and Synthesis by Means of Atomic Functions
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10.1615/TelecomRadEng.v56.i6-7.50
Victor Filippovich
Kravchenko
Kotelnikov Institute of Radio Engineering and Electronics, Russian Academy of Sciences, 11-7, Mokhovaya St., Moscow 125009, Russia; Bauman Moscow State Technical University, 5, Vtoraya Baumanskaya St., Moscow 105005 Russia; Scientific and Technological Center of Unique Instrumentation, Russian Academy of Sciences, 15, Butlerova St., Moscow 117342, Russia
The work is devoted to analysis of Atomic Functions (AF) applications to principal problems of antennas theory. The analysis follows the result of the solution of some applied problems, such as is to determine the field of antenna in the far zone when the distribution of the current or the tangential components of the electromagnetics field on the surface of antenna is known, and of synthesis is to determine a current (or a field) in the antenna by means of radiation pattern in the zone, and boundary value problems of the antenna theory is to determine the field in antenna and surrounding area when excitation by outside sources and boundary conditions are known. In the second part of paper, the new algorithm for numerical solution of radiation pattern synthesis problems is proposed. A number of numerical examples were performed to illustrate the effectiveness of presented approach. Unique approximating properties of Atomic Functions (AF) let us apply more simple and effective method, which result in significant computational gain, and, hence, the solution requires less memory and run time.
Theoretical Aspects of Radar Imaging Using the Bayes Nonparametric Estimation Strategy
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10.1615/TelecomRadEng.v56.i6-7.60
Yuriy V.
Shkvarko
Visiting professor in the FIMEE, University of Guanajuato, Mexico
Rene
Jaime-Rivas
Head of FIMEE at the University of Guanajuato, 36730 Salamanca, Gto. Mexico
Victor
Ayala-Ramirez
Universidad de Guanajuato FIMEE, Tampico 912, Colonia Bellavista, Salamanca, Guanajuato, 36730 MEXICO
In this work, we consider the theoretical aspects related to the problem of remote radar probing of the natural environment (in particular, Earth surfaces) with the purpose of electronic imaging. The problem is stated and treated as an inverse ill-posed problem of estimating the power scattering function (PSF) of the surface referred to as the radar image of the wavefield sources distributed in the environment. The randomized maximum entropy a priori model of the PSF is suggested and theoretically grounded. We derive the formula that is useful to interpret the information theoretical formalism of the randomized PSF. The Bayes non-parametrical estimation strategy is applied to form the radar images involving the maximum entropy a priori model of the PSF and projection-type constraints imposed on the desired solution. We also discuss the issues related to performance evaluation and computational implementation of the developed method.
Modeling of an Active Camera for Selection and Tracking of Visual Landmarks in Mobile Robot Navigation
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10.1615/TelecomRadEng.v56.i6-7.70
Victor
Ayala-Ramirez
Universidad de Guanajuato FIMEE, Tampico 912, Colonia Bellavista, Salamanca, Guanajuato, 36730 MEXICO
Michel
Devy
Yuriy V.
Shkvarko
Visiting professor in the FIMEE, University of Guanajuato, Mexico
Rene
Jaime-Rivas
Head of FIMEE at the University of Guanajuato, 36730 Salamanca, Gto. Mexico
We present some active visual functionalities for a landmark-based navigation system. This paper is focused on two functions: (1) the selection of the landmarks that must be tracked from a given robot situation, and (2) the active control of the camera modalities (zoom and pan parameters). Using a discretization of the configuration space, visibility and utility grids are dynamically built and updated during the path execution: a simple function exploits these grids to select the optimal parameters. Several experimental results demonstrate the validity of the approach.
A Three Dimensional Growth Model for Primary Cancer
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10.1615/TelecomRadEng.v56.i6-7.80
Sabas
Flores-Ascencio
Professor at the Enginnery Superior School at the National Polytechnic Institute of Mexico
Hector Manuel
Perez-Meana
National Polytechnic Institute of Mexico
Mariko
Nakano-Miyatake
National Polytechnic Institute, IPN, Mexico City
Origin and Evolution of Cyclonic Vortices
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10.1615/TelecomRadEng.v56.i6-7.90
Mikhail Fedorovich
Ivanov
Institute for High Energy Density of the Russian Academy of Sciences, 127412, Izhorskaya St. 13/19, Moscow, Russia
M.E.
Povarnitsin
Institute for High Energy Density of the Russian Academy of Sciences, 127412, Izhorskaya St. 13/19, Moscow, Russia
Fedor Fedorovich
Kamenets
Moscow Institute of Physics and Technology, 141700, Institutski per., 9, Dolgoprudny, Russia
N.S.
Knyazev
Moscow Institute of Physics and Technology, 141700, Institutski per., 9, Dolgoprudny, Russia
The numerical algorithm for solving of the three-dimensional convective flows with vortexes at moderate Reynolds and Rayleigh numbers has been developed. The testing of the code showed a good agreement with laboratory experiment on modeling convective vortex in rotating cuvette. We study an evolution of cyclonic vortexes under different conditions, such as switching off heating or rotation. Processes of attenuation and decay of vortexes are suggested to be accompanied by Rayleigh-Taylor instability and unsteady effects.
A Survey of Adaptive Analog Filters
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10.1615/TelecomRadEng.v56.i6-7.100
Hector Manuel
Perez-Meana
National Polytechnic Institute of Mexico
Mariko
Nakano-Miyatake
National Polytechnic Institute, IPN, Mexico City
Luis
Nino-de-Rivera
SEPI ESIME Culhuacan, National Polytechnic Institute (IPN), Av. Santa Ana No. 1000, C.P. 04430 Mexico D.F. MEXICO
Juan Carlos
Sanchez-Garcia
SEPI ESIME Culhuacan, National Polytechnic Institute (IPN), Av. Santa Ana No. 1000, C.P. 04430 Mexico D.F. MEXICO
Gonzalo
Duchen-Sanchez
SEPIESIME Culhuacan, National Polytechnic Institute (IPN) Av. Santa Ana No. 1000, C.P. 04430 Mexico D.F. MEXICO
Adaptive systems, a subject of active research during the last several years, have been mainly implemented in a digital way. However the analog realization forms may present several advantages over the digital ones in applications requiring high convergence speed with lower power consumption, and small sizes. This paper proposes analog adaptive filters based on gradient search based and modified Hopfield networks adaptation methods. Proposed systems provide solution to some of the problems still exiting in the analog adaptive filtering field such as: the distortion due to imperfect integration, increasing the convergence speed of the analog system and the development of analog adaptive system with low sensitivity to additive noise without requiring an explicit matrix inversion. Computer simulation results show that the proposed systems present much better convergence performance than conventional ones in several practical applications.
Statistical Analysis of Linear Filters Driven By Non-White Noise
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10.1615/TelecomRadEng.v56.i6-7.110
Vladimir A.
Kazakov
Ruben P.
Hernandez
Telecommunications engineering from National Polytechnic Institute of Mexico in 2000
The problem of the statistical analysis of the multidimensional linear filters is considered on the basis of kinetic equations for the non-Markovian stochastic processes. The kinetic coefficients are calculated using the convolution integral instead of the system of differential equations. The advantage of this method is a reduction of the dimension of the problem. Two examples are given and some results of a statistical simulation are presented when the input is the binary Markovian process.
Wavelet Coefficient Thresholding for Radar Image Compression
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10.1615/TelecomRadEng.v56.i6-7.120
Mikhail V.
Sabelkin
National Aerospace University "KhAI"
In this paper several well-known thresholding techniques: hard, soft, quantile and universal are represented. A new adaptive thresholding technique is proposed. It is known that radar images are affected by the phenomenon of multiplicative noise. This phenomenon influences the performance of 2D wavelet transform based compression algorithms and it can be improved if suitable algorithm is used as a preprocessing stage. It is shown that the homomorphic transform can be used as a suitable preprocessing technique. Comparison between well-known thresholding techniques and the proposed adaptive thresholding technique is performed for the real radar image. It is shown that the adaptive thresholding use improves the performance of the wavelet transform based compression.