Modeling in terms of cell dynamical systems (CDS) is advocated as an efficient tool to sort out correct guesses about the mathematical essence of macroscopic nonlinear phenomena with space-time patterns. CDS is a map from a discrete pattern at time t to the one at t+1. With the aid of segregation processes, the CDS modeling is illustrated. Numerical schemes are introduced which are often stable for fairly large increments to bridge conventional partial differential equation (PDE) models and CDS models. Although these schemes with large increments usually do not give correct solutions to the original PDE, they could still give quantitatively accurate results for macroscopic observables. Thus it is meaningful to discuss qualitatively accurate schemes.

In this paper, in the first place, a slightly version upped Urabe type theorem of convergence criterion is presented for the modified Newton method. Then, based on this theorem, a posteriori stopping criterion is presented for a class of numerical methods of calculating solutions including the simplicial approximate homotopy method for nonlinear equations. By this criterion it is estimated whether an approximate solution satisfies the conditions of the Urabe theorem or not. Finally, it is shown that under a certain mild condition a class of simplicial approximate homotopy methods such as Merrill's method generate an approximate solution which satisfies our stopping criterion in restarting finite steps.

This paper clarifies some properties of the Poincar map of the almost periodic oscillation, which is generated by a periodically excited nonlinear system described by a Linard equation. Arguments in this paper are based on the extended Linard theorem already published by the present authors and are focused on the almost periodic oscillations which may occur in the Linard system under a certain constraint on the external force. As the main result, it is shown that the Poincar map of the almost periodic oscillation drawn on the Linard plane forms a simple closed continuous curve, under an explicitly given condition on the external force e (t) = A sin (ωt+θ), for arbitrary value of the amplitude A except for a set of the values ω with zero measure.

A new channel allocation algorithm named "Channel Segregation" is proposed for small cell mobile radio systems. The proposed scheme in principle requires no effort in the cell design and is highly adaptive to the change of propagation conditions. Channel allocation is determined in each base station in a distributed manner, without measuring propagation conditions in advance. By learning from statistical data of carrier sense results, each base station makes its favorite channel independently so that unnecessary interferences will not occur. As a result, each base station captures its favorite channels for dedicated use. Simulation results show that channel segregation actually takes place by a distributed control. Performances are measured in two criteria, interference probability due to carrier sense error and total blocking probability. Compared with a system without segregation, the proposed sheme decreases interference probability by 1/10-1/100, and increase channel utilization efficiency by 28% for a 2-dimensional interference model.

Design concepts and antenna features of Japanese mobile communication systems are clarified. The complete package of design tools used to structure the sidelobe characteristics of the low sidelobe tilted beam antenna(LSTA)is shown. This antenna is now in use as the base station antenna in Japan. It is shown that sidelobe levels of less than 20dB can be achieved in multipath propagation environments. This antenna can be simultaneously used for transmission and reception because of its very low intermodulation characteristics. Bench tests show the 7th order level is less than 10dBµ even with a total antenna input of 160 watts. A new vehicular mounted antenna, the vertical space diversity antenna is examined. It is shown that a correlation coefficient of less than 0.5 can be achieved with an antenna spacing of 0.5 to 1 wavelength. A compact antenna whose total length is about 1.7 wavelengths is described. The latest Japanese portable phone antenna, a very compact diversity antenna employing a whip and an inverted F antenna, is tested. A correlation coefficient of about 0.2 is achieved with an antenna spacing of less than 0.1 wavelength. It is shown that radiation pattern differences between antennas, caused by mutual coupling, are the main cause of this small correlation coefficient.

This paper addresses thecurrent research and recent trends of image communications research that fall into the theme of intelligent communications in two parts --Intelligent Image Coding and Communications with Realistic Sensations. In Part , the theme of intelligent image coding and the particular example of encoding of human facial images using an intelligence-based approach is presented. A classification of the different generations--five generations--of image coding systems is first given. First and second generations are the direct wave-form coding and the statistical encoding methods. The third and fourth generations are the use of model-based anaylsis-synthesis and recognition/reconstruction methods, respectively. The fifth generation is the full intelligent coding system that can understand the semantics, intention, motives and other factors in an image. The progress in the model-based analysis-synthesis approach to image coding is reviewed and the particular example of its application to the encoding of human facial images is examined. In this example, the methods of modeling human face, the extraction of feature points and the tracing of motion in a facial image, as well as the analysis and synthesis of facial expressions are discussed. In Part , the current research in the new paradigm of telecommunication--Communications with Realistic Sensations is introduced. The progress in the research of a Virtual Space Teleconference System as an example of this new paradigm is presented. The possibility of delivering a very high level of sensation realism to a receiver is made real by recent advances in computer graphics and computer animation techniques, in stereoscopic display techniques that enable life-size images to be displayed on a wide screen and in computer human interface technologies, particularly, for recording human hand, head and eye positions. Progress of these technologies in the context of the research on the Virtual Space Teleconference System are discussed. The research on how to communicate and manipulate 3-D objects in a such an environment is examined.

In Japan extensive efforts have been made for the practical application of the 1125/60 HDTV system for broadcasting and non-broadcasting uses. In this paper recent progress in the 1120/60 HDTV is reviewed focusing on the studio standard and the developments of HDTV equipment such as very high sensitivity pick-up tubes, HDTV CCD devices and a 33-inch flat panel plasma display. Then the transmission of HDTV signals via broadcasting satellite, communications satellite and CATV are described in addition to the digital transmission of HDTV signals. Finally some examples of non-broad-cast application of the 1125/60 HDTV are briefly discussed.

This paper demonstrates results of a numerical experiment on bifurcation phenomena in a two-degrees-of-freedom Duffing's type forced oscillatory system. The regions in the parameter plane (amplitude B and angular frequency ν of the external force) are given, in which various phenomena; chaos, hyperchaos, Hopf-bifurcations, doubling of torus, crisis and windows are observed. Existence of chaos and hyperchaos is confirmed by calculating the Lyapunov exponents. Bifurcations from invariant closed curves to chaotic attractors are also considered. For this system, two types of bifurcations from invariant closed curves to chaotic attractors through doubling of torus are observed; in one case, the doubling is interrupted by modelocking, then a chaotic attractor appears suddenly, in another case, the doubling seems to continue infinitely.

The amplitude and phase of the alpha wave in EEG were studied while flicker stimulation was applied or removed. On applying the stimulation, the amplitude was once attenuated, then entrainment was achieved and reverse phase pattern between posterior and anterior regions was stabilized. As the stimulation was removed, the entrainment state ceased rapidly and the spontaneous activity revived.

Efficient device simulation methods to realize circuit level analyses have been proposed. Highly conductive wire regions, the current source, and lumped elements such as resistances and capacitances can be handled within the framework of a present device simulation software. Additionally, the simulation area can be reduced and computational efforts can be saved by adopting the inner Neumann boundary condition between devices which affect each other very little except through the wire region. The regularity of the coefficient matrix can be preserved in all cases, so it is possible to get stability of matrix solver and save computer memory. The advantage of matrix regularity is enhanced to speed up when using a vector-concurrent computer. Hence, the computational cost can be saved considerably. These numerical techniques have been implemented in the authors' device simulation software.

High efficiency amplifier construction techniques are investigated focusing on UHF band transmitting power amplifiers intended for cellular portable telephones and the state of the art amplifiers are presented. First, it is shown that high efficiency amplifiers are indispensable to attain pocket sized portable units through a theoretical analysis using a simple model. When about 1 W of transmitting power is required, it is desirable for the amplifier to operate with an efficiency of over 40%. Secondly, the switching mode scheme is described as the most effective technical means to achieve high amplifier efficiency. State of the art switching mode amplifiers, the Harmonic Reaction Amplifier (HRA) and the Linearized Saturation Amplifier with Bidirectional Control (LSA-BC), are presented as examples of nonlinear and linear amplifiers respectively. Basic operation mechanisms are shown. Experimental HRA and LSA-BC are constructed to determine their practically attainable efficiencies. Power-added efficiencies of 75% and 40% are recorded from a 1.7 GHz band 3 W HRA for CW and a 1.5 GHz band 1 W LSA-BC for π/4 QPSK respectively. These values indicate that these types of amplifier can be applied to pocket sized portable radio units.

The problem of embedding two-dimensional grids into hypercube parallel computers is the main subject of this work. Two methods (called dilation 1 and dilation 2 embedding) are used to embed a grid and their performances are evaluated. In dilation 1 (d1) embedding a grid edge connecting 2 points is mapped into one hypercube link, and in dilation 2 (d2) embedding there are cases in which one grid edge is mapped into two hypercube links. Generally, this makes the performance of d2 embedding poorer than that of d1 embedding, as communication between some adjacent grid points have to be forwarded through an intermediate link. However, there are cases where d2 embedding allows a more efficient use of the hypercube, as more processors can be used in the embedding. Thus, it is necessary to find out what kind of embedding achieves the best performance. We assume that the number of grid points is larger than the number of processors, and then propose a method to divide the grid in rectangular parts of arbitrary size called fragments, which are actually embedded into a processor. Using the parameters of a commercial hypercube, the performances of several grids embedded under different conditions are evaluated. As a result, the relation between hypercube size and grid size is found to have a strong influence on the choice of the embedding method.

Based on the loss behavior of optical fibers coated with high and low thermal expansion coefficient (α) secondary jackets in the -180 to 20 temperature range, the mechanism of loss increase has been discussed. The low α liquid-crystalline-polyester(LCP)-jacketed fiber shows the microbending loss of 5 dB/km at -180, while the high α nylon-jacketed fiber exhibits the maximum microbending loss of about 30 dB/km at -120 and then shows the decrease in loss with decreasing temperature. The relatively low loss increase in the LCP-jacketed fiber arises from crystallization of the primary silicone and slight eccentricity of the LCP jacket. The unusual loss behavior in the nylon-jacketed fiber can be explained in terms of the arrangement of randomly distributed fiber curvature at -120, which is predicted by Yabuta's fiber-buckling model and supported by the occurrence of fiber-strain relaxation.

A new simulation system, which is composed of two-dimensional process simulator and inference engine, has been developed as one of the prototype systems for analysing process tolerance and fluctuation in individual process parameters. A general concept of the system, algorithm of process fluctuation analysis and inference engine of AI software package are presented. Typical evidences of results obtained are also demonstrated.

A surface mount device (S. M. D.) type miniature isolator has been developed. Its dimension is 6.8 6.9 4 mm3 and weight is 0.75 g. Both the volume and weight have been reduced to one-third compared with a conventional small model. A resin case and metalplated terminals on its surface are used to realize this configuration. By using a simplified simulation technique the most suitable ferrite size and the most suitable magnet are determined to minimize an insertion loss and to realize good temperature stability. Consequently, 0.8 dB insertion loss, 15 dB isolation and 14 dB return loss are obtained within 3 % bandwidth at 836.5 MHz in the practical operating temperature range between -25 and +75. Handling power capability of 2.5 W for forward input and 0.75 W for reverse input are achieved at +25.

Secondary phase modulation was proposed for lowering the signal frequency band of open-loop optical fiber gyroscopes. Extracting the lowered frequency spectra, the rotation rate was derived from the gyroscope signal and the drift in the optical parameters were compensated.

Two-dimensional simulations of small-signal parameters (such as transconductance, gate capacitance and cutoff frequency) of GaAs MESFETs are performed in which impurity compensation by deep levels in the semi-insulating substrate is considered. It is shown that these are strongly affected by impurity densities in the substrate. For higher acceptor densities in the substrate, both transconductance and cutoff frequency become higher, because the substrate current is reduced. For low acceptor densities in the substrate, the gate capacitance takes a relatively large value even if the gate voltage is deeply negative, because the channel extends into the substrate and electrons there contribute to the capacitance. It is concluded that to utilize high-frequency performance of GaAs MESFETs, the acceptor densities in the semi-insulating substrate should be made high.

This letter proposes a new framework for ASIP (Application Specific Integrated Processor) development. The system is called IDEAS (Integrated Design Environment for Application Specific Integrated Processor). IDEAS accepts a set of application programs and its expected data as input, and profiles these programs both statically and dynamically. According to the profiled results, the system decides the architecture of ASIP, and synthesizes the CPU core design of the ASIP, and generates the software development tools for the ASIP such as compiler and simulator.