The synergistic effects obtained by adopting both space diversity reception and adaptive equalization play a very important role in circuit outage reduction. This paper quantitatively analyzes these synergistic effects when dispersive and flat fading occur simultaneously. Analytical results show that the synergistic effects are of the same magnitude as the adaptive equalizer improvement factor when only dispersive fading causes outage. The synergistic effects gradually disappear when noise is the predominant cause of outage.

Induced noises from breaking contact arc discharge and sliding contact discharge of dc motor are measured by pick up coil and current probe. Statistical properties, amplitude distribution probability (APD), of induced noise waveform are analyzed by simple method using intermediate frequency of spectrum analyzer. It is shown that APD characteristics can be used to estimate statistical characteristics and peak value of induced noise. Simulation model of the noise made by the combination of Gaussian noise is mentioned. The model called the composite noise generator (CNG) can be good fit to the real characteristics of both noises from breaking arc and dc motor. Applications of the CNG for noise filter using toroidal coil shows that the CNG is useful to realize the test of noise suppression characteristics. What parameters of the CNG should be considered is described for further applications.

Polynomials are called permutation polynomials if they induce bijective functions. This paper investigates algebraic properties of permutation polynomials over a finite field, especially properties associated with permutation cycles. A permutation polynomial has a simple structure but good randomness properties suitable for applications. The cycle structure of permutations are considered to be related to randomness. We investigate the algebraic structure from the viewpoint of randomness. First we show the relationship between polynomials and permutations using a matrix equation. Then, we give a general form of a permutation polynomial corresponding to a product C1C2Ck of pairwise disjoint cycles. Finally, permutation polynomials with fixed points -or with 2, 3 and 4-cycles -and their compositions are given together with distribution of degree of the permutation polynomials.

Optical Feedering between Base Stations and Control Station is an effective technique for future microcellular mobile communication systems. The use of Laser Diode (LD) in such a system leads to the generation of intermodulation products, which consequently affect a system performance and ultimately restrain the maximum number of users that the system can serve. The problem becomes further intensified in case of CDMA system which is a candidate for future cellular mobile and personal communication systems. In this paper LD's Nonlinearity compensation technique for Direct Sequence spread spectrum CDMA signals in optical communication system is presented. This technique involves the implementation of a nonlinear block herein after called Post Nonlinearity Recovery Block (PNRB). This block is designed to exhibit the characteristics inverse to those of LD. The block is designed theoretically by deriving the complete expressions for Transfer functions. Some useful results of theoretical investigation of a proposed scheme have been presented, which form the basis for the experimental test system. The work is novel because, (i) Compensation analysis has been carried out for DS-CDMA signals for the first time, and (ii) Compensation has been proposed on the control station instead of base station, which is different from the conventional techniques and offers several additional advantages. Performance of the system with and without PNRB is evaluated by Intermodulation Distortion (IMD) and SNR Analysis. The results show that LDs' nonlinearity distortion level can be compensated to a remarkable extent.

In order to simulate the mechanism of particle growth by film deposition, imaginary-particle formation method has been newly developed. By using this formation method, the particle size, the particle height and the position of particle on a wafer could be controlled very easily. In this study, the imaginary-particles of various size larger than 0.15 micron and various height were formed on a wafer. By using these imaginary-particles, the effects of a deposition method, a film thickness, a particle size and a particle height upon the particle growth were investigated. As deposition methods, low pressure CVD method, plasma CVD method and sputtering method were compared. As a result, in all deposition method, it's clear that the particle growth doesn't depend on the initial size, and is proportional to the film thickness. Their particle growth rates are characterized by the deposition method, and their values are 1.9, 1.1 and 0.64 in low pressure CVD, plasma CVD and sputtering method, respectively. These values can be explained by the step coverage decided by the deposition method. Furthermore, the particle growth on imaginary-particle was compared with that on the real-particle. It is clear that the growth mechanism of the real-particle is closely similar to that of imaginary-particle, and the study by use of the imaginary-particle is very effective to make clear the mechanism of particle growth. Therefore, the particle size which should be controlled before deposition process is necessary to be decided by counting the particle growth shown in this paper.

This paper introduces a new image representation method that is named the projective image representation (PIR). We consider an image as a collage of symmetric segments each of which can be well represented by its projection data of a single orientation. A quadtree-based method is adopted to decompose an image into variable sized segments according to the complexity within it. Also, we deal with the application of the PIR to the image compression and propose an efficient algorithm, the quadtree-structured projection vector quantization (QTPVQ) which combines the PIR with the VQ. As the VQ is carried out on the projection data instead of the pixel intensities of the segment, the QTPVQ successfully overcomes the drawbacks of the conventional VQ algorithms such as the blocking artifact and the difficulty in manipulating the large dimension. Above all, the QTPVQ improves the subjective quality greatly, especially at low bit rate, which makes it applicable to low bit rate image coding.

An invertible length preserving transducer is called a weakly invertible finite automaton (WIFA for short). If the first letter of any input string of length τ + 1 is uniquely determined by the corresponding output string by a WIFA and its initial state, it is called a WIFA with delay τ. The composition of two WIFAs is the natural concatenation of them. The composition is also a WIFA whose delay is less than or equal to the sum of the delays of the two WIFAs. In this paper we derive various results on a decomposition of a WIFA into WIFAs with smaller delays. The motivation of this subject is from theoretical interests as well as an application to cryptosystems. In order to capture the essence of the decomposability problem, we concentrate on WIFAs such that their input alphabets and their output alphabets are identical. A WIFA with size n of the input and output alphabet is denoted by an n-WIFA. We prove that for any n > 1, there exists an n-WIFA with delay 2 which cannot be decomposed into two n-WIFAs with delay 1. A one-element logic memory cell is a special WIFA with delay 1, and it is called a delay unit. We show that for any prime number p, every strongly connected p-WIFA with delay 1 can be decomposed into a WIFA with delay 0 and a delay unit, and that any 2-WIFA can be decomposed into a WIFA wiht delay 0 and a sequence of k delay units if and only if every state of the 2-WIFA has delay k.

The SAR distributions over a homogeneous human model exposed to a near field of a short electric dipole in the resonant frequency region were calculated with the spatial resolution of 1cm3 which approximated 1g tissue by using the FDTD method with the expansion technique. The dependences of the SAR distribution on the distance between the model and the source and on frequency were investigated. It was shown that the large local SAR appeared in the parts of the body nearest to the source when the source was located at 20cm from the body, whereas the local SAR were largest in the narrow sections such as the neck and legs when the source was farther than 80cm from the model. It was also shown that, for the near-field exposure in the resonant frequency region, the profile of the layer averaged SAR distribution along the main axis of the body of the human model depended little on frequency, and that the SAR distribution in the section perpendicular to the main axis of the human body depended on frequency. The maximum local SAR per gram tissue over the whole body model was also determined, showing that the ratios of the maximum local SAR to the whole-body averaged SAR for the near-field exposure were at most several times as large as the corresponding ratio for the far-field exposure, when the small source located farther than 20cm from the surface of the human model.

In this communication we propose to solve the problem of reconstruction from limited data using a statistical regularization method based on a Bayesian information criterion. The minimization of the Bayesian information criterion, which is used here as an objective index to measure the goodness of an estimate, gives the optimum value of the smoothing parameter. By doing so, we could reduce the inversion problem to a simple minimization of a one-variable nonlinear function. The application of such a technique overcomes the nonuniqueness of the solution of the ill-posed problem and all shortcomings of many iterative methods. In the light of simulation and application to real data, we propose a slight modification to the Bayesian information criterion to reconstruct the wave energy distribution at the ionospheric base from the observation of radio wave electromagnetic field on the ground. The achieved results in both the inversion problem and the wave direction finding are very promising and may support other works so far suggested the use of Bayesian methods in the inversion of ill-posed problems to benefit from the valuable information brought by the a priori knowledge.

In identification of a finite impulse response (FIR) model using noise-corrupted input and output data, the least squares type of estimation schemes such as the ordinary least squares (LS), the corrected least squares (CLS) and the total least squares (TLS) method become often numerically unstable, when the true input signal to the system is strongly correlated. To overcome this ill-conditioned problem, we propose a regularized CLS estimation method by introducing multiple regularization parameters to minimize the mean squares error (MSE) of the regularized CLS estimate of the FIR model. The asymptotic MSE can be evaluated by considering the third and fourth order cross moments of the input and output measurement noises, and an analytical expression of the optimal regularization parameters minimizing the MSE is also clarified. Furthermore, an effective regularization algorithm is given by using the only accessible input-output data without using any true unknown parameters. The effectiveness of the proposed data-based regularization algorithm is demonstrated and compared with the ordinary LS, CLS and TLS estimates through numerical examples.

This paper presents some tighter bounds on universal noiseless coding, in particular, the lowerbound tighter than Davisson et al.'s for finite sequence and the upperbound for some typical universal data compression. We find that Davisson et al.'s bound satisfies some optimization in the case of using the Jeffreys prior and also that the derived upperbound in this paper is within O(1/n) from the Clarke and Barron asymptotics in the case of some restricted typical universal data compression defined in the paper.

This letter describes the power absorption of a cylindrical man model placed near a flat reflector exposed to TE microwave. The numerical results show that the absorption is in some cases an order of magnitude or more greater than that of the man model without a reflector.

A soft magnetic force microscope (MFM) tip was used to evaluate the magnetic recording characteristics of compositionally separated Co-Cr perpendicular media. Small magnetic bits were recorded on thick (350 nm). and thin (100 nm) films, focusing on the fineness of compositionally separated microstructures. MFM images showed bit marks 230 and 150 nm in diameter, measured at full-width at half maximum (FWHM) for the thick and thin films, respectively. These results verify that the recordable bit size can be decreased by using a thinner film with a finer compositionally separated microstructure. Simulation was used to clarify the relationship between the actual sizes of the recorded bits and the sizes of their MFM images. The recorded bit size was found to closely correspond to the FWHM of the MFM bit images.

The magnetic properties and the structure of electroless-deposited NiFeB films were investigated in comparison with those of electrodeposited NiFe films. The electroless-deposited NiFeB film with 27at% Fe content had the lowest coercivity, H, as low as 0.5 Oe with a saturation magnetic flux density, Bs, of 1.0 T. The saturation magnetostriction, λ, and the uniaxial magnetic anisotropy, Hk, were 5.010-6 and 10 Oe, respectively, which were larger than those of the conventional, electrodeposited permalloy film. The permeability of as-deposited Ni70Fe27B3 film was 1000 at 1 MHz. In order to improve the permeability, the film was heated at 200 in a magnetic field applied in the hard-axis direction to decrease the Hk value, and the permeability became 2000 at 1 MHz. The crystal structure and grain size of NiFeB and NiFe films were investigated by XRD, THEED and TEM. Both films with low Hc had an fcc structure; the grain size of the NiFeB film was smaller than 10 nm, while that of the NiFe film was larger, approximately 20 nm. The results suggested that the electroless-deposited NiFeB film had a larger magnetic anisotropy than the electrodeposited NiFe film. Moreover, the films with Hc less than 10 Oe ded not show clear difference between their TEM bright images and THEED patterns.

Mesa structures have been investigated to optimize a buried-heterostructure (BH) for a GaInAsP/InP surface-emitting (SE) laser regrown by metalorganic chemical vapor deposition (MOCVD), and it has been found that a square mesa top pattern of which the sides are at an angle of 45 to the 011 orientation is suitable. A 1.3-µm GaInAsP/InP square buried heterostructure (SBH) SE laser with this mesa structure has been demonstrated and low-threshold CW oscillation (threshold current Ith=0.45 mA) at 77 K and low-threshold room-temperature pulsed oscillation (Ith=12 mA) have been obtained.

We propose an algorithm for image decomposition based on Hadamard functions, realized by answer-in-weights neural network, which has simple architecture and is explored with steepest decent method. This scheme saves memory consumption and it converges fast. Simulations with least mean square (LMS) and absolute mean (AM) errors on a 128128 image converge within 30 training epochs.

This paper presents a simple and efficient method for estimation of parameters useful for textured image analysis. On the basia of a 2-D Wold-like decomposition of homogenenous random fields, the texture field can be decomposed into a sum of two mutually orthogonal components: a deterministic component and an indeterministic component. The spectral density function (SDF) of the former is a sum of 1-D or 2-D delta functions. The 2-D autocorrelation function (ACF) of the latter is fitted to the assumed anisotropic ACF that has an elliptical contour. The parameters representing the ellipse and those representing the delta functions can be used to detect rotation angles and scaling factors of test textures. Specially, rotation and scaling invariant parameters, which are applicable to the classification of rotated and scaled textured images, can be estimated by combining these parameters. That is, a test texture can be correctly classified even if it is rotated and scaled. Several computer experiments on natural textures show the effectiveness of this method.

A rat-race hybrid-ring which includes a coupled-line called microwave C-section is proposed for size reduction. The perfect input match, isolation, equal power split and certain phase differences between two output ports can be satisfied at center frequency as in a normal hybrid-ring. The size of the proposed circuit becomes smaller than that of a normal rat-race built up with a folded non-coupled 3/4-wavelength transmission line, although the frequency characteristics are slightly damaged by the electromagnetic coupling between two folded strips. Theoretical results based on the even and odd mode decomposition method are in good agreement with those of the experimental circuit fabricated at 1 GHz.

A new concept for a navigation and communication satellite system has been proposed. The navigation satellite system that forms the basis of the proposed system has been studied by one of the authors and extended to add a mobile communication function to the system. The satellite system consists of 15 satellites in quasi-geostationary orbit (QGEO) that have a geostationary altitude and high inclination and provide global coverage and positioning capability to the observer through only reception of the range measurement signals generated at the satellites, which are in the same configuration as the satellites in Global Positioning System (GPS), Three satellites out of the 15 satellite are designated to install a subsystem for mobile satellite communication in order to satisfy mobile communication convenience as required in a Future Air Navigation System's (FANS) concept of International Civil Aviation Organization (ICAO). The case studies of 15-satellites constellations demonstrate not only an acceptable positioning accuracy over the whole globe, but also an accuracy distribution weighted on the north pole region as an example of a weighted accuracy distribution. The addition of a mobile communication function suggests a unified system of satellite navigation and communication, which might provide convenience for the civil aviation industry, because the two functions currently depend on different systems.

The performance of coded multi-pulse pulse position modulation (MPPM) consisting of m slots and 2 pulses, denoted as (m, 2) MPPM, with imperfect slot synchronization is analyzed. Convolutional codes and Reed-Solomon (RS) codes are employed for (m, 2) MPPM, and the bit error probability of coded (m, 2) MPPM in the presence of the timing offset is derived. In each coded (m, 2) MPPM, we compare the performance of some different code rate systems. Moreover, we compare the performance of both systems at the same information bit rate. It is shown that in both coded systems, the performance of code rate-1/2 coded (m, 2) MPPM is the best when the timing offset is small. Wheji the timing offset is somewhat large, however, uncoded (m, 2) MPPM is shown to perform better than coded (m, 2) MPPM. Further, convolutional coded (m, 2) MPPM with the constraint length k7 is shown to perform better than RS coded (m, 2) MPPM for the same code rate.