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.

Given two terms and their rewriting rules, an unreachability problem proves the non-existence of a reduction sequence from one term to another. This paper formalizes a method for solving unreachability problems by abstraction; i. e. , reducing an original concrete unreachability problem to a simpler abstract unreachability problem to prove the unreachability of the original concrete problem if the abstract unreachability is proved. The class of rewriting systems discussed in this paper is called β rewriting systems. The class of β rewriting systems includes very important systems such as semi-Thue systems and Petri Nets. Abstract rewriting systems are also a subclass of β rewriting systems. A β rewriting system is defined on axiomatically formulated base structures, called β structures, which are used to formalize the concepts of "contexts" and "replacement," which are common to many rewritten objects. Each domain underlying semi-Thue systems, Petri Nets, and other rewriting systems are formalized by a β structure. A concept of homomorphisms from a β structure (a concrete domain) to a β structure (an abstract domain) is introduced. A homomorphism theorem (Theorem1)is established for β rewriting systems, which states that concrete reachability implies abstract reachability. An unreachability theorem (Corollary1) is also proved for β rewriting systems. It is the contraposition of the homomorphism theorem, i. e. , it says that abstract unreachability implies concrete unreachability. The unreachability theorem is used to solve two unreachability problems: a coffee bean puzzle and a checker board puzzle.

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.

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.

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.

Electrochemomechanical deformation (ECMD) of poly(o-methoxyaniline) (PoMAn) film has been studied in various acid solutions, such as Cl-, HSO4-, BF4-, and p-toluene sulfate. The magnitude of ECMD of the film depends linearly on the degree of oxidation of the film similarly to the case of polyaniline (PAn). 2. 53% of deformation ratios along the stretched direction are obtained for 30% of reduction. In contrast to that of PAn, however, the ECMDs of PoMAn do not markedly depend on the kind of anions. Transient responses of current and deformation are investigated by the potential application stepwise and the diffusion coefficient of ions in films. The results are discussed in terms of the effect of substituted methoxy group.

A more judicious choice of trial functions to implement the Improved Circuit Theory (ICT) application to multi-element antennas is achieved. These new trial functions, based on Tai's modified variational implementation for single element antennas, leads to an ICT implementation applicable to much longer co-planar dipole arrays. The accuracy of the generalized impedance formulas is in good agreement with the method of moments. Moreover, all these generalized formulas including the radiation pattern expressions are all in closed-form. This leads to an ICT implementation which still requires much shorter CPU time and lesser computer storage compared to method of moments. Thus, for co-planar dipole arrays, the proposed implementation presents a relatively very efficient method and would therefore be found useful in applications such as CAD/CAE systems.

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.

Let L be any class of languages, L' be one of the classes of context-free, context-sensitive and recursively enumerable languages, and Σ be any alphabet. In this paper, we show that if the following statement (1) holds, then the statement (2) holds. (1) For any language L in L over Σ, there exist an alphabet Γ including Σ, a homomorphism h:Γ*Σ* defined by h(a)=a for aΣ and h(a)=λ (empty word) for aΓ-Σ, a Dyck language D over Γ, and a language L1 in L' over Γ such that L=h(DL1). (2) For any language L in L over Σ, there exist an alphabet of k pairs of matching parentheses Xk, Dyck reduction Red over Xk, and a language L2 in L' over ΣXk such that L=Red(L2)Σ*. We also give an application of this result.

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.

Let L be any class of languages, L' be a class of languages which is closed under λ-free homomorphisms, and Σ be any alphabet. In this paper, we show that if the following statement (1) holds, then the statement (2) holds. (1) For any language L in L over Σ, there exist an alphabet of k pairs of matching parentheses Xk, Dyck reduction Red over Xk, and a language L1 in L' over ΣXk such that L=Red(L1)Σ*. (2) For any language L in L over Σ, there exist an alphabet Γ including Σ, a homomorphism h : Γ*Σ*, a Dyck language D over Γ, and a language L2 in L' over Γ such that L=h(DL2). We also give an application of this result.

The valid region for the application of the conventional Improved Circuit Theory (ICT) in the analysis of wire antennas is established. To further extend the application of ICT to the analysis of much longer antennas, Tai's trial function is used to derive new formulas for the impedance matrix. Unlike the conventional ICT trial function, Tai's trial functions lead to input impedances which are finite irrespective of antenna length. Results of the new ICT impedance formulas are comparable in accuracy with the general method of moments. Moreover, since all the elements of the new formula have been expressed in closed-form, the resulting ICT algorithm is still superior in terms of computer running time with lesser storage requirement compared to other conventional methods like method of moments. This would enhance ICT applications in CAD/CAE systems.

This paper describes a trial of evaluating the proper characteristics of multiple sound insulatain systems from their output responses contaminated by unknown background noises. The unknown parameters of sound insulation systems are first estimated on the basis of hte linear time series on an intensity scale, describing functionally the input-output relation of the systems. Then, their output probability distributions are predicted when an arbitrary input noise passes through these insulation systems.

A flat stick-shaped whip antenna was developed for Japanese commercial portable telephones. It provides a high gain even though it is short and retractable. It is an open-sleeve type antenna. i.e., the inductance-loaded dipoleantenna element parallels a twin-lead type feeder. It suppresses the currents on the radio housing even at short antenna lengths. Moreover, it is easy to achieve two resonant characteristies and able to construct retractable type. A relatively high gain is gotten even when the antenna is in a retracted state. This antenna has a suitable configuration for commercial portable telephones. This paper first calculates, the current suppression of the housing on a principal model of this antenna, i.e., without a twin-lead feeder. The second analysis determines the effects of the twin-lead feeder and the dielectric coat on the antenna. Next,the two resonant technique and the configuration for the retractable-type antenna describes. In addition, the return loss and radiation pattern for the trial model were measured. The return loss shows that the two resonant characteristics and the bandwidths of the high and low resonant frequencies are 2.2% and 1.5%(VSWR2), respectively. For when the antenna is extended, radiation patterns are nearly the same as for the case of the 1/2 wavelength dipole antenna, and the antenna efficiencies are -1.6 dB at 820 MHz and -1.1 dB at 950 MHz. Other hand, for the retracted state, they are destroyed by the housing currents, but the efficiency is relatively high of -1.8 dB at 950 MHz. In these experiments, it is clear that the antenna achieves high performances.

The coupling response of an external transient electromagnetic field to a transmission line is considered. An experiment has been conducted to verify the line equations for a transmission line excited externally by a transient near field. The model field is generated by a monopole antenna installed in the vicinity of the transmission line and driven by a step waveform. The waveform is analyzed into discrete spectrum components using a Fourier transform. The frequency-domain field components affecting the transmission line are estimated by the moment method, and then the induced frequency-domain voltage at the terminal load is converted into a time-domain voltage using an inverse Fourier transform. Comparison between the measured and the computed values provides verification of the line equations. The coupling mechanism is discussed from the experimental results. It seems equivalently that the transmission line picks up the field, generated at the feed point and the top point of the monopole antenna, at both terminal ends.