Journal of Intelligent & Fuzzy Systems - Volume 5, issue 1

Article Type: Other

DOI: 10.3233/IFS-1997-5107

Citation: Journal of Intelligent and Fuzzy Systems, vol. 5, no. 1, pp. I-I, 1997

Authors: Aihara, Kazuyuki | Katayama, Ryu

Article Type: Other

DOI: 10.3233/IFS-1997-5101

Citation: Journal of Intelligent and Fuzzy Systems, vol. 5, no. 1, pp. 1-2, 1997

Authors: Iokibe, T. | Fujimoto, Y. | Kanke, M. | Suzuki, S.

Article Type: Research Article

Abstract: In recent years, the study of chaos has been drawing attention. As chaos application, we propose a short-term prediction of the time series under chaotic behavior. Short-term prediction is to find some deterministic regularity in a phenomenon that was thought of as noise or an irregularity and thereby predict its state in the near future. Short-term prediction employs the following technique: the observed time series is reconstructed in a multidimensional state space according to the Takens' theorem of embedding. Local reconstruction is the mode that uses the vector neighboring the data vector, including the latest observed data. Proposed as the …practical methods of this prediction are Gram-Schmidt's orthogonal system method, the tessellation method, etc. However, the drawback to these methods is that prediction becomes impossible if the selected neighboring vector is not linearly independent. 1n the tessellation method, it also has the shortcoming that the time period of calculation increases abruptly as the dimension of reconstructed state space increases. To overcome such disadvantages, this article proposes the local fuzzy reconstruction method. First we explain deterministic chaos. Next we show the approach to short-term prediction of a chaotic time series in detail. Finally, examination is made of the result of the preceding local fuzzy reconstruction method applied to the short-term prediction of the logistic map and the Lorenz attractor, which are known as typical chaotic time series, and tap water demand data, traffic density, and power demand data as social phenomena. Show more

DOI: 10.3233/IFS-1997-5102

Citation: Journal of Intelligent and Fuzzy Systems, vol. 5, no. 1, pp. 3-21, 1997

Authors: Kuwata, Kaihei | Watanabe, Masahide | Katayama, Ryu

Article Type: Research Article

Abstract: In digital communication systems, a linear transversal equalizer was applied to signal equalization. But because of the nonlinearity of the equalization problem, it was desirable to incorporate some nonlinearity in the adaptive equalizer structure. We considered the application of the radial basis function (RBF) network to the adaptive equalizer and compared the performance of the equalizer using an RBF network between the maximum absolute error (MAE) selection method and the orthogonal least squares (OLS) method as a learning procedure. By comparing the MAE method with the OLS method, we show that the MAE method can achieve a more efficient performance …in terms of bit error rate with fewer basis functions than the OLS method. Show more

DOI: 10.3233/IFS-1997-5103

Citation: Journal of Intelligent and Fuzzy Systems, vol. 5, no. 1, pp. 23-31, 1997

Authors: Ikeguchi, Tohru | Aihara, Kazuyuki

Article Type: Research Article

Abstract: This article deals with a problem on estimating correlation dimensions of possible attractors reconstructed from biological time series data. The analyzed data are the five Japanese vowels, /a/, /i/, /u/, /e/, and /o/, and two pulse waves in human finger capillary vessels. The estimation algorithm used here is not the conventional Grassberger-Procaccia algorithm, but a new method proposed by Judd, which solves some problems intrinsic to the conventional method. To avoid several artifacts that might be involved in the analysis, such as the limited number of time series data, the finite resolution of data points, and the existence of the …observational noise, the statistical procedure or the method of surrogate data is also applied to the real data. As a result, the existence of strange attractors with fractional dimensions are implied in the Japanese vowels /a/ and /o/. Although nonlinearities in the Japanese vowels /i/, /u/, and /e/, and pulse waves in human capillary vessels are implied by the analysis with the method of surrogate data, we cannot conclude that these data have definite fractal structures. Show more

DOI: 10.3233/IFS-1997-5104

Citation: Journal of Intelligent and Fuzzy Systems, vol. 5, no. 1, pp. 33-52, 1997

Authors: Yamada, Taiji | Aihara, Kazuyuki

Article Type: Research Article

Abstract: In this article we study the spatiotemporal complex dynamics of chaotic neural networks and their relationships with combinatorial optimization. In particular, we apply chaotic neural networks to the traveling salesman problem as a typical example of combinatorial optimization problems and analyze the nonlinear computational dynamics by comparing its characteristics with those of other dynamical models.

DOI: 10.3233/IFS-1997-5105

Citation: Journal of Intelligent and Fuzzy Systems, vol. 5, no. 1, pp. 53-68, 1997

Authors: Ishii, Shin

Article Type: Research Article

Abstract: A globally coupled map (GCM) model is a network of chaotic elements that are globally coupled with each other. We previously proposed an associative memory system based on GCM, which has a better ability than the Hopfield network. This result indicates that the dynamics of our system is more efficient than that of the Hopfield network. However, even in our system, spurious memories, that is, the system's equilibria that do not correspond to any of the proper memories, do exist. In this article a modified associative memory system is proposed in which spurious memories are noticeably reduced. This is achieved …by modifying the chaotic dynamics of the system. With this improvement, our system's memory capacity and basin volumes are expanded a great deal. Some experimental results in comparison with those of a neural network that employs a nonmonotonic output junction are also shown. Show more

DOI: 10.3233/IFS-1997-5106

Citation: Journal of Intelligent and Fuzzy Systems, vol. 5, no. 1, pp. 69-83, 1997