Journal of Intelligent & Fuzzy Systems - Volume 4, issue 1

Article Type: Other

DOI: 10.3233/IFS-1996-4107

Citation: Journal of Intelligent and Fuzzy Systems, vol. 4, no. 1, pp. I-I, 1996

Authors: Sanou, Katsuaki | Romaniuk, Steve G. | Hall, Lawrence O.

Article Type: Research Article

Abstract: The task of implementing a simple rule-based production system in a connectionist architecture is discussed. To implement a connectionist-based production system, it is essential to be capable of representing explicit rules by means of simple neuronlike computing units. The architecture described here uses a local representation based upon the instance oriented symbolic/connectionist expert system SC net. The problems of variable binding and variable value instantiation are solved in the context of this system. The network is built such that only one value is bound to a variable during each rule firing cycle. Issues regarding serialization and working memory consistency are …also solved. An example implementation, the Farmer's Dilemma planning problem, is given to illustrate the potential of this approach. The article shows how many different rule bases may be mapped onto a connectionist architecture for parallel execution. Show more

DOI: 10.3233/IFS-1996-4101

Citation: Journal of Intelligent and Fuzzy Systems, vol. 4, no. 1, pp. 1-18, 1996

Authors: Stoll, Kenneth E. | Ralston, Patricia A.S. | Ward, Thomas L.

Article Type: Research Article

Abstract: In this article a simplified fuzzy controller implementation is explored and shows clearly that it is an input-output interpolating algorithm derived from a set of production rules. The simplified controller development is similar to that in the literature. Unique to this work is the compelling description of fuzzy controllers as interpolating devices, with the explanation supported analytically. Such a presentation is in contrast to the usual description of a fuzzy controller as a rule-based expert system that bypasses an underlying analytical description of the relationship between input and output produced by the rule base. The reader is given an analysis …showing that a fuzzy controller can be viewed as an input-output relationship represented by a breakpoint function, and that the breakpoint function may be obtained directly from the control rules in simple cases. For engineers and others trained in conventional control theory, this article demonstrates that they need not be practiced in fuzzy set theory or fuzzy logic to take advantage of the utility of the fuzzy technique in designing nonlinear controllers. Show more

DOI: 10.3233/IFS-1996-4102

Citation: Journal of Intelligent and Fuzzy Systems, vol. 4, no. 1, pp. 19-32, 1996

Authors: Layne, Jeffery R. | Passino, Kevin M.

Article Type: Research Article

Abstract: A learning system possesses the capability to improve its performance over time by interaction with its environment. A learning control system is designed so that its learning controller has the ability to improve the performance of the closed-loop system by generating command inputs to the plant and utilizing feedback information from the plant. In this brief article, we introduce a learning controller that is developed by synthesizing several basic ideas from fuzzy set and control theory, self-organizing control, and conventional adaptive control. We utilize a learning mechanism that observes the plant outputs and adjusts the membership functions of the rules …in a direct fuzzy controller so that the overall system behaves like reference model. The effectiveness of this fuzzy model reference learning controller is illustrated by showing that it can achieve high performance learning control for a nonlinear time-varying rocket velocity control problem and a multi-input multi-output two-degree-of-freedom robot manipulator. Show more

DOI: 10.3233/IFS-1996-4103

Citation: Journal of Intelligent and Fuzzy Systems, vol. 4, no. 1, pp. 33-47, 1996

Authors: Dohnal, M.

Article Type: Research Article

Abstract: A fractal/chaos analysis and discriminative power evaluation of knowledge bases are presented. They can be used by knowledge engineers to make knowledge acquisition activities more objective. The fractal analysis gives a numerical parameter (fractal dimension). It describes certain relations between general and specific knowledge items (for example between on-line measurements and general rules of thumbs). The discriminative power analysis is used to quantify one aspect of a knowledge base “quality.” Both formal tools are applicable regardless of types of knowledge bases. The article describes their fuzzy interpretations. A simple demonstrative example (a set of 17 fuzzy statements) and a realistic …fractal recommendation (fuzzy versus neural control algorithms) are presented in detail. Show more

DOI: 10.3233/IFS-1996-4104

Citation: Journal of Intelligent and Fuzzy Systems, vol. 4, no. 1, pp. 49-63, 1996

Authors: Oh, Deock Gil | Choi, Jin Young | Lee, Choong Woong

Article Type: Research Article

Abstract: Fuzzy adaptive equalizers show a good performance in channels with highly nonlinear decision boundaries due to their universal function approximation capabilities. However, the computational load for the parameter adaptation is much higher than that of linear equalizers. This article considers a new approach to fuzzy adaptive equalizers to reduce the computational complexity. The approach in this article has the distinctive feature of conditional linear equalizations based on a perceptron-based filter. The premise part is automatically constructed by a competitive self-organizing scheme using decision feedback vectors as well as observed channel vectors. The corresponding resultant part is realized in the form …of a perceptron-based filter for the observed channel vectors. As a result, the proposed equalizer shows a good performance with a computational load similar to that of linear equalizers at each symbol time. The effectiveness of our approach is shown through computer simulations of bit error rate performances and computational complexity. Show more

DOI: 10.3233/IFS-1996-4105

Citation: Journal of Intelligent and Fuzzy Systems, vol. 4, no. 1, pp. 65-73, 1996

Authors: Wu, Q.M. Jonathan | de Silva, Clarence W.

Article Type: Research Article

Abstract: Self-tuning of a control system may be effectively carried out by means of a properly designed, fuzzy, decision-making system. Optimization of the operation of such knowledge-based systems requires consideration of several factors including proper selection of fuzzy resolution, shape of the membership functions of fuzzy variables, and the level of overlap among various fuzzy states of a variable. This article studies the effect of fuzzy resolution on the processing speed and response accuracy of a fuzzy logic based control or tuning system. First, the underlying analytical concepts are presented, and on that basis, experiments are carried out to study this …effect of fuzzy resolution. Response of the experimental system is studied at different levels of fuzzy resolution. Next, the concept of resolution switching is introduced and incorporated into the experimental system. The results obtained with and without resolution switching are comparatively studied to demonstrate the effectiveness of resolution switching. Show more

DOI: 10.3233/IFS-1996-4106

Citation: Journal of Intelligent and Fuzzy Systems, vol. 4, no. 1, pp. 75-85, 1996