Deterministic nonlinear prediction is applied to both artificial and real time series data in order to investigate orbital-instabilities, short-term predictabilities and long-term unpredictabilities, which are important characteristics of deterministic chaos. As an example of artificial data, bimodal maps of chaotic neuron models are approximated by radial basis function networks, and the approximation abilities are evaluated by applying deterministic nonlinear prediction, estimating Lyapunov exponents and reconstructing bifurcation diagrams of chaotic neuron models. The functional approximation is also applied to squid giant axon response as an example of real data. Two metnods, the standard and smoothing interpolation, are adopted to construct radial basis function networks; while the former is the conventional method that reproduces data points strictly, the latter considers both faithfulness and smoothness of interpolation which is suitable under existence of noise. In order to take a balance between faithfulness and smoothness of interpolation, cross validation is applied to obtain an optimal one. As a result, it is confirmed that by the smoothing interpolation prediction performances are very high and estimated Lyapunov exponents are very similar to actual ones, even though in the case of periodic responses. Moreover, it is confirmed that reconstructed bifurcation diagrams are very similar to the original ones.

It is shown that five optimal and one quasioptimal binary codes with respect to the Griesmer bound can be obtained from cyclic codes over GF(2fm). An [m(2em - 1), em, 2em-1m] code, a [3(22e - 1), 2e, 322e-1] code, a [2(22e - 1), 2, (22e+2 - 4)/3] code, a [3(22e - 1), 2, 22e+1 - 2] code, and a [3(22e - 1), 2(e+1), 322e-1 - 2] code are optimal and a [2(22e - 1), 2(e + 1), 22e - 2] code is quasi-optimal.

The capability of generalization is the most desirable property of a learning system. It is well known that to achieve good generalization, the complexity of the system should match the intrinsic complexity of the problem to be learned. In this work, introduction of fractal connection structure in nonlinear learning systems like multilayer perceptrons as a means of improving its generalization capability in classification problems has been investigated via simulation on sonar data set in underwater target classification problem. It has been found that fractally connected net has better generalization capability compared to the fully connected net and a randomly connected net of same average connectivity for proper choice of fractal dimension which controlls the average connectivity of the net.

In this paper, after the introduction of the definition of State Controlled Cellular Neural Networks (SC-CNNs), it is shown that they are able to generate complex dynamics of circuits showing strange behaviour. Theoretical propoitions are presented to fix the templates of the SC-CNNs in such a way as to exactly match the dynamic behaviour of the circuits considered. The easy and cheap implementation of the proposed SC-CNN devices is illustrated and a gallery of experimentally obtained strange attractors are shown to confirm the practical suitability of the outlined strategy.

In this paper, Chay's bursting pancreatic β-cell model is updated to include a role for [Ca2+]ER, the luminal calcium concentration in the endoplasmic reticulum (ER). The model contains a calcium current which is activated by voltage and inactivated by [Ca2+]i. It also contains a cationic nonselective current (INS) that is activated by depletion of luminal Ca2+ in the ER. In this model, [Ca2+]ER oscillates slowly, and this slow dynamic drives electrical bursting and the [Ca2+]i oscillations. This model is capable of providing answers to some puzzling phenomena,which the previous models could not (e. g., why do single pancreatic β-cells burst with a low frequency while the cells in an islet burst with a much higher frequency ?). Verification of the model prediction that [Ca2+]ER is a primary oscillator that drives electrical bursting and [Ca2+]i oscillations in pancreatic β-cells awaits experimental testing. Experiments using fluorescent dyes such as mag-fura-2-AM could provide relevant information.

An efficient algorithm is proposed for finding all solutions of piecewise-linear resistive circuits The algorithm is based on the idea of "contraction" of the solution domain using a sign test. The proposed algorithm is efficient because many large super-regions containing no solution are eliminated in early steps.

A new type of noncausal stochastic model is proposed to represent a random image with double peak spectrum. The model based on the assumption that the double peak spectrum is expressed by a product of two spectra located at two symmetric positions in the 2D spatial frequency space. Estimation of model parameters is made by means of minimizing the "whiteness" which was proposed in authors' previous work. In a simulation for model estimation we make use of computer-generated random images with double peak spectrum. Comparing this with the estimation by a causal model, we demonstrate that the present method can better estimate not only the spectral peak location but also the spectral shape. The proposed model can be extend to an image model with multl-peak spectrum. However, Increase of parameters makes the model estimation more difficult We try a model with triple peak spectra since a real texture image usually possesses a spectral peak at the origin besides the two peaks. A result shows that the estimation of three spectral positions are good enough, but their spectral shapes are not necessarily satisfactory. It is expected that the estimation of multi-peaked spectral model can be made better by improving the process of minimizing the "whiteness."

This paper presents an improved pragmatic approach to coded modulation design which provides higher coding gains especially for very noisy channels including those with Rayleigh fading. The signal constellation using four equally utilized dimensions implemented with two correlative carrier frequencies is adopted to enhance the performance of the pragmatic approach previously proposed by Viterbi et al.. The proposed scheme is shown to perform much better by analysis of system performance parameters and extensive computer simulation for practical channel conditions. The bandwidth and power efficiencies are also analyzed and discussed to provide more design flexibility for different communications environments.

This study clarifies the effects of network complexity and network map transformation on the ability of network managers to use graphic network displays. Maps of Japan and the United States with outlines of their respective prefectures or states were displayed on a CRT. Each map displayed a fictitious network of nodes and their interconnections. These networks were two-level hierarchical and non-meshed, meaning that each low-level node was connected to a single high-level node, but not all high-level nodes were linked together. The subjects, task was to identify a path between two low-level nodes. In each trial, two low-level nodes were highlighted, and the subject attempted to find the shortest path between these nodes. This was done by using a mouse to select intermediate nodes. Completing a path required a minimum of 4 node traversals. Three variables were manipulated. First, the number of nodes was defined as the total number of low-level nodes in a network (70, 150, or 200). The second variable was the level of transformation. Very densely populated areas of the maps were systematically transformed to reduce congestion. There were three levels of transformation. The final variable was the country map used, that is, the map of Japan and the map of the United States. Several behavioral measures were used. The most informativ. appeared to be the time required to complete a path (the response time), and how often subjects returned to previous portions of a path (back-ups). For both of these measures, the data pattern was essentially the same. Increasing the number of nodes hurts performance. This was particularly pronounced when the map of Japan was tested. However, as the level of transformation increased, this effect was substantially reduced or completely eliminated. The results are discussed in terms of engineering rules and guidelines for designing graphical network representations.

In this paper partial response signalling and trellis coded modulation are considered together to improve bandwidth efficiency and error performance for M-QAM and denoted as Modified/Quadrature Partial Response-Trellis Coded Modulation (M/QPR-TCM) and two new non-catastrophic schemes M/6QPR-TCM and M/9QPR-TCM are introduced for 4QAM. In colored noise with correlation coefficient less than zero, the proposed schemes perform better than in AWGN case. Another interesting result is that when the combined system is used on a Rician fading channel, the bit error probability upper bounds of the proposed systems are better than their counterparts the 4QAM-TCM systems with 2 and 4 states, respectively, for SNR values greater than a threshold, which have the best error performance in the literature.

In this paper, an extention for Haddad's method, which is the time-domain stability analysis on scalar nonlinear control systems, to multi-variable nonlinear control systems are proposed, and it is shown that these results are useful for the stability analysis of nonlinear control systems with various types of fuzzy controllers.

In this paper, we propose a modified Hamming network which contains less connection numbers and faster convergence speed. Besides, the real weight of subnet can also be transformed into integer weight. As so it is suitable for the hardware implementation of VLSI.

In this paper, scattering problem of the grating coupler is analyzed by the mode-matching method in the sense of least squares for the gaussian light beam incidence. This coupler has a periodic groove structure of finite extent, which is formed on the surface of the core layer of the symmetric thin-film waveguide. In the present method, the approximate scattered fields of each region of the grating coupler are described by the superpositions of the plane waves with band-limited spectra, respectively. These approximate wave functions are determined by the minimization of the mean-square boundary residual. This method results in the simultaneous Fredholm type integral equations of the second kind for these spectra. The first and second order approximate solutions of the integral equations are derived analytically and the coupling efficiency and scattered fields are analyzed on the basis of those solutions. A qualitative and physical consideration for the scattering problem of the grating coupler is presented with the fundamental data derived from approximate solutions in this paper.

In the present communication we propose the application of unsupervised Artificial Neural Networks (ANN) to solve general ill-posed problems and particularly we apply them to the the estimation of the direction of arrival (DOA) of VLF/ELF radio waves. We use the wave distribution method which consists in the reconstruction of the energy distribution of magnetospheric VLF/ELF waves at the ionospheric base from observations of the wave's electromagnetic field on the ground. The present application is similar to a number of computerized tomography and image enhancement problems and the proposed algorithm can be straightforwardly extended to other applications in which observations are linearly related to unknowns. Then, we have proven the applicability and also we indicate the superiority of the ANN to the conventional methods to handle this kind of problems.

This paper presents a new timing-driven global routing method for standard cell layout. The proposed method can explicitly consider the timing constraint between two registers and minimize the channel density under the given timing constraint. In the proposed method, first, we determine the initial global routes. Next, we improve the global routes to satisfy the timing constraint between two registers as well as to minimize the channel density. Finally, for each cell row, the nets incident to terminals on the cell row are assigned to channels to minimize the channel density using 0-1 integer linear programming. We also show the experimental results of the proposed method implemented on an engineering workstation. Experimental results show that the proposed method is quite promising.

In order to apply formal design verification, it is necessary to describe formally and correctly the specification of the circuit under verification. Especially when we apply conventional OBDD-based logic comparison method for verifying combinational circuits, another correct" logic circuits or Boolean formulae must be given as the specification. It is desired to develop an efficient automatic design verification method which interprets specification that can be described easier. This paper provides a new verification method which is useful for combinational circuits such as arithmetic circuits. The proposed method efficiently verifies whether a designed circuit satisfies a specification given by recurrence equations. This enables us to describe easily an error-free specification for arithmetic circuits. To perform verification efficiently using an ordinary OBDD package, an efficient truth-value rotation algorithm is developed. The truthvalue rotation algorithm efficiently generates an OBDD representing f(x + 1 (mod 2n)) from a given OBDD representing f(x). By experiments on SPARC station 10 model 51, it takes 180 secs to generate an OBDD for designed circuit of 23-bit square function, and additional 60 secs is sufficient to finish verifying that it satisfies the specification given by recurrence equations.

In forthcoming multimedia environments, continuous-media data, such as video and audio data, will be used by a variety of multimedia applications. Multimedia applications require efficient and flexible support from real-time operating systems. This is because the changes in system and network loads require dynamic management of real-time thread behavior. If threads are implemented at the user level, operations on threads can be processed at the user level, and the efficient management of threads becomes possible by avoiding kernel interventions. Thus, we can provide an effective platform for multimedia applications. The goal of our work is to realize high-performance user-level real-time threads which satisfy the above requirements of multimedia systems. In this paper we describe the design and implementation of a user-level real-time threads package, called RTC-Threads, which is being developed on the RT-Mach microkernel. The results of performance evaluations show that our user-level real-time threads outperform real-time kernel-provided threads, which are implemented in the microkernel, in terms of efficiency and accuracy.

In this paper, we discuss problems in design and fault masking of multiple-valued cellular arrays where basic cells having simple switch functions are arranged iteratively. The stuck-at faults of switch cells are assumed to be fault models. First, we introduce a universal single-level array and derive the ratio of the number of single faults whose influence can be masked to the total number of single faults. Next, we propose a universal two-level array that outputs correct values even if single faults occur in it and derive the ratio of the number of double faults whose influence can be masked compared to the total number of double faults. By evaluating the universal single-level array and the universal two-level array from the viewpoints of design and fault masking, we show that the latter is superior to the former. Finally, we compare our universal two-level array with formerly presented arrays in order to demonstrate the advantages of our universal two-level array.

This paper deals with the scattering of a plane wave from a two-dimensional random thin film. For a Gaussian random disorder, a first order solution is derived explicitly by a probabilistic method. It is then found that ripples appear in angular distributions of the incoherent scattering. Furthermore, the incoherent scattering is enhanced in the directions of backscattering and specular reflection. Physical processes that yield such an enhanced scattering are discussed. Numerical examples of the coherent and incoherent scattering are illustrated in figures.

Process-related variation of optimal noise figures (Fo) in pulse-doped GaAs MESFET's is discussed in this paper. Fluctuation in gate length of the proposed devices is shown to be a dominant source of variation in noise parameters. The statistical distribution of the optimal noise figure is modeled by using the gaussian approximation of the distribution in gate length; the probability density function of Fo is derived. A comparison between the calculated results by the derived probability density function and the measured distribution of Fo showed good agreement.