An inverse scattering problem in three dimensional two layered media is investigated. The shape and the location of the acoustic scatterer buried in one half-space are determined. With some a priori information, it becomes possible to solve this problem in three dimensions. Using the moment method, the scattered field is obtained for the estimated scatterer. An iterative procedure based on the Newton's method for the nonlinear least square problem is able to solve the inverse scattering problem. Some numerical results are presented.

First order line seach optimization techniques gained essential practical importance over second order optimization techniques due to their computational simplicity and low memory requirements. The computational excess of second order methods becomes unbearable for large optimization tasks. The only applicable optimization techniques in such cases are variations of first order approaches. This article presents one such variation of first order line search optimization technique. The presented algorithm has substantially simplified a line search subproblem into a single step calculation of the appropriate value of step length. This remarkably simplifies the implementation and computational complexity of the line search subproblem and yet does not harm the stability of the method. The algorithm is theoretically proven convergent, with superlinear convergence rates, and exactly classified within the formerly proposed classification framework for first order optimization. Performance of the proposed algorithm is practically evaluated on five data sets and compared to the relevant standard first order optimization technique. The results indicate superior performance of the presented algorithm over the standard first order method.

We present two estimation methods for camera rotation from two images obtained by the active camera before and after rotation. Based on the representation of the projected rotation group, quasi moment features are constructed. Camera rotation can be estimated by applying the singular value decomposition (SVD) or Newton's method to tensor quasi moment features. In both cases, we can estimate 3D rotation of the active camera from only two projected images. We also give some experiments for the estimation of the actual active camera rotation to show the effectiveness of these methods.

The features of the method of moment (MoM) and the finite difference time domain (FDTD) method for numerical analysis of the electromagnetic scattering problem are presented. First, the integral equations for the conducting wire, conducting plane and the dielectric materials are described. Importance to ensure the condition of the continuity of the current of the scatterers is emphasized and numerical examples for a conducting structure involving a junction of wire segment and planar segment is presented. Finally, the advantages and the disadvantages of the FDTD method are discussed.

It is not rare case that a floated metal plate exists nearby high speed circuit traces. Heatsink placed on a IC chip nearby circuit traces, metal enclosure or circuit traces in a compact designed product may be a good example. It may be also seen such structure for a shield box and circuit traces confined. It is generally known that such metal plate as placing nearby circuit trace may change circuit trace parameters and then resonance frequency associated with the circuit trace. In this study, we clarified resonance frequency variation with comprehensive observation of input impedance of microstrip line that is an essential model of circuit traces on a printed circuit board. Since such structure is created in various cases in product designs, we believe that the results shown in this study may be useful for EMC design as well as signal integrity. For computation, method of moment was used.

An accurate and efficient numerical solution is presented for a two-dimensional electromagnetic wave scattering from a multilayered resistive strip grating embedded in a dielectric slab. Both E- and H-waves are treated. The problem is formulated into a set of integral equations, which is solved by the moment method accompanied by a regularization procedure. The resultant set of linear algebraic equations has the form of the Fredholm second kind, and therefore yields stable and accurate numerical solutions. The power distribution is computed for several grating parameters. Attention is paid to seek a set of parameters that maximizes absorption in the strips. The low frequency approximate formulas are also derived. This analysis would be useful in designing electromagnetic wave absorbers.

Hallen's integral equation for cylindrical antennas is modified to deal with finite gap excitation. Because it is based on more realistic modeling, the solution is more accurate, and the convergence is guaranteed. The new equation is written with a new excitation function dependent on the gap width. The moment method analysis is presented where the piecewise sinusoidal surface current functions are used in Galerkin's procedure. Total, external and internal current distributions can be determined. Numerical results for cylindrical antennas with wide variety of gap width and radius are shown, and are compared with the numerical results by the Pocklington type integral equation and those by measurement.

In this paper, we apply the discrete wavelet transform (DWT) and the discrete wavelet packet transform (DWPT) with the Daubechies wavelet of order 16 to effectively solve for the electromagnetic scattering from a one-dimensional inhomogeneous slab. Methods based on the excitation vector and the [Z] matrix are utilized to sparsify an MoM matrix. As we observed, there are no much high frequency components of the field in the dielectric region, hence the wavelet coefficients of the small scales components (high frequency components) are very small and negligible. This is different from the case of two-dimensional scattering from perfect conducting objects. In the excitation-vector-based method, a modified excitation vector is introduced to extract dominant terms and achieve a better compression ratio of the matrix. However, a smaller compression ratio and a tiny relative error are not obtained simultaneously owing to their deletion of interaction between different scales. Hence, it is inferior to the [Z]-matrix-based methods. For the [Z]-marix-based methods, our numerical results show the column-tree-based DWPT method is a better choice to sparsify the MoM matrix than DWT-based and other DWPT-based methods. The cost of a matrix-vector multiplication for the wavelet-domain sparse matrix is reduced by a factor of 10, compared with that of the original dense matrix.

The wavelet matrix transform approach, in combination with the method of moments (MoM), is applied to solve the electromagnetic scattering problem of an array of metal strips. The problem is first discretized by the conventional MoM to obtain a dense impedance matrix, then the wavelet matrix transform is applied to produce a sparse matrix. This approach avoids a great number of integral computations existing in the wavelet basis expansion method and provides fast approach to solution for the scattering problem. Daubechies' wavelet is chosen as the mother wavelet to construct a sparse wavelet matrix so that the matrix-matrix multiplications occurring in the transform cost only O(N2) with N unknowns. Numerical tests show that the computation cost necessary for solving the resultant sparse matrix is only O(N log N). An appropriate choice of the number of vanishing moments of wavelets is suggested from consideration of total computation cost and accuracy of solutions.

A binary moment diagram, which was proposed for arithmetic circuit verification, is a directed acyclic graph representing a function from binary-vectors to integers (f : {0,1}n Z). A multiplicative binary moment diagram is an extension of a binary moment diagram with edge weights attached. A multiplicative binary moment diagram can represent addition, multiplication and many other functions with polynomial numbers of vertices. Lower bounds for division, however, had not been investigated. In this paper, we show an exponential lower bound on the number of vertices of a multiplicative binary moment diagram representing a quotient function or a remainder function.

Extremely small aperture radial line slot antennas (RLSAs) are analyzed by method of moments. At first, the analysis model of cylindrical waveguide in terms of rectangular cavity modes is confirmed for a RLSA with a spiral slot arrangement. The overall VSWR as well as rotational symmetry of the actual structure of RLSAs is predicted for the first time and is confirmed experimentally. Secondly, the minimum diameter of the concentric array RLSA is estimated for which the conventional analysis model of a rectangular waveguide is valid for the design of matching slot pairs at the shorted periphery of the radial waveguide. It is found that the curvature and cylindrical short wall at aperture periphery must be considered in the design and analysis of small RLSAs with the gain lower than about 25 dBi.

This paper presents scattering characteristics of a TE electromagnetic plane wave by a photo-induced plasma strip grating in a semiconductor slab at millimeter wave frequencies. The characteristics are analyzed by using the moment method and estimated numerically over a frequency band from 30-50 GHz. It is shown that the resonance anomaly in the grating can be controlled by changing not only the periodic light illumination pattern but also the plasma density.

This paper describes a classification method for rotated and scaled textured images using invariant parameters based on spectral-moments. Although it is well known that rotation invariants can be derived from moments of grey-level images, the use is limited to binary images because of its computational unstableness. In order to overcome this drawback, we use power spectrum instead of the grey levels to compute moments and adjust the integral region of moment evaluation to the change of scale. Rotation and scale invariants are obtained as the ratios of the different rotation invariants on the basis of a spectral-moment property with respect to scale. The effectiveness of the approach is illustrated through experiments on natural textures from the Brodatz album. In addition, the stability of the invariants with respect to the change of scale is discussed theoretically and confirmed experimentally.

A combined mode-matching and moment method is proposed to calculate the capacitance matrix of wedge-supported cylindrical microstrip lines with an indented ground. Each indent is modeled as a multilayered medium in which the potential distribution is systematically derived by defining reflection matrices. An integral equation is derived in terms of the charge distribution on the strip surfaces. Galerkin's method is then applied to solve the integral equation for the charge distribution. The effects of strip width, strip separation, indent depth, and indent shape are analyzed.

Time spread (TS) pulse position modulation (PPM) signals have been proposed for CDMA applications, where the envelope detection is employed instead of coherent detection for easier synchronization of PPM. In this paper, a new method of deriving symbol error probability (SEP) of TS PPM signals in the presence of interference is introduced. The analysis is based on the moment technique. The maximum entropy criterion for estimating an unknown probability density function (PDF) from its moments is applied to the evaluation of PDF of envelope detector output. Numerical results of SEP are shown for 4, 8 and 16PPM in the practical range of signal-to-noise power ratio (SNR) and signal-to-interference power ratio (SIR) of 5, 10 and 20 dB. SEP by the union bound is also given for comparison. From the results it is noted that when PPM multilevel number is small, the union bound goes near to SEP by the proposed method, but when it increases the difference of the SEP by the bound and proposed method becomes larger. The effect of central frequency offset of TS-filter is evaluated as an illustrative example.

Minato has proposed canonical representation for polynomial functions using zero-suppressed binary decision diagrams (ZBDDs). In this paper, we extend binary moment diagrams (BMDs) proposed by Bryant and Chen to handle variables with degrees higher than l. The experimental results show that this approach is much more efficient than the previous ZBDDs' approach. The proposed approach is expected to be useful for various problems, in particular, for computer algebra.

Nonuniform transmission lines are crucial in integrated circuits and printed circuit boards, because these circuits have complex geometries and layout between the multi layers, and most of the transmission lines possess nonuniform characteristics. In this article, an efficient numerical method for analyzing nonuniform transmission lines has been presented by using the Chebyshev expansion method and moment techniques. Efficiency on computational cost is demonstrated by numerical example.

A moment-based method is proposed to estimate the illumination change between two images containing affinetransformed objects. The change is linearly modeled with parameters to be estimated by histograms due to its invariance of translation, rotation, and scaling. The parameters can be correctly estimated for an appropriate illumination change by normalizing the moments of the histograms.

Theoretical values of site attenuation for broadband receiving antenna or the antenna factor of broadband antenna over the frequency range from 30 MHz to 1 GHz have been calculated or measured by some researchers. For a frequency range over 1 GHz, wire antennas or horn antennas should be used. However, the theoretical site attenuation or antenna factor over 1 GHz have never yet been calculated. A CLS (Conical Log-periodic Spiral) antenna is generally used for EMC/EMI measurements in the microwave band as a broadband wire antenna for the swept frequency method. However, this antenna has the defect that its use results in the loss of polarization information. So we proposed an improved CLS antenna which has linear polarization. This new CLS antenna has another wire wound symmetrically to that of the standard CLS antenna. For this reason, we named it a double-wire CLS antenna. The double-wire CLS antenna loses no polarization information. We calculated the height pattern and the frequency characteristics of CSA (Classical Site Attenuation) for the double-wire CLS antenna when used for receiving, or used for both transmitting and receiving, as well as the antenna factor. Moreover, NSA (Normalized Site Attenuation) when the double-wire CLS antenna is used for receiving or used for both transmitting and receiving in free space were calculated.

A new numerical technique, termed the method of matrix-order reduction (MMOR), is developed for handling electromagnetic problems in this paper, in which the matrix equation resulted from a method-of-moments analysis is converted either to an eigenvalue equation or to another matrix equation with the matrix order in both cases being much reduced, and also, the accuracy of solution obtained by solving either of above equations is improved by means of a newly proposed generalized Jacobian iteration. As a result, this technique enjoys the advantages of less computational expenses and a relatively good solution accuracy as well. To testify this new technique, a number of wire antennas are examined and the calculated results are compared with those obtained by using the method of moments.