A linearizing control scheme for a highly nonlinear pneumatic muscle (PM) system is presented in this paper. Linearizing controllers have been widely used in the control of robotic systems. Since PM is a highly nonlin...
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While studies of the role of fuzzy logic in natural language certainly exist, it is not clear that the use of fuzzy logic to represent linguistic constructs is anything more than an engineering convenience. This paper...
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While studies of the role of fuzzy logic in natural language certainly exist, it is not clear that the use of fuzzy logic to represent linguistic constructs is anything more than an engineering convenience. This paper suggests that one reason this situation obtains is because fuzzy logic has been used strictly to elucidate static aspects of natural language (particularly aspects of the lexicon). If one examines dynamic features of natural language, on the other hand, new possibilities for connections between fuzzy logic and natural language emerge. In particular, some results from category theory are used to show that fuzzy logic can have a role in explaining certain otherwise rather obscure properties of linguistic comparatives in English.
In this paper, we propose the definition of fuzzy rough approximation decomposability, discuss the properties of several fuzzy rough approximations and give several decision theorems for fuzzy rough approximation deco...
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ISBN:
(纸本)0780379187
In this paper, we propose the definition of fuzzy rough approximation decomposability, discuss the properties of several fuzzy rough approximations and give several decision theorems for fuzzy rough approximation decomposability.
A very general model of a system representing information is presented. Under the assumptions that this model applies to product spaces and that information is not lost in the expansion to these product spaces we conc...
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A very general model of a system representing information is presented. Under the assumptions that this model applies to product spaces and that information is not lost in the expansion to these product spaces we conclude that a semiring is the proper model for the algebra involved. Some indication of the nature of the information measures appropriate to the semiring are presented.
In this paper, we present a fuzzy logic based method of fault detection and diagnosis in gas turbine engines. The fuzzy logic system rule base is derived using heuristics extracted from designed experiments and flight...
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In this paper, we present a fuzzy logic based method of fault detection and diagnosis in gas turbine engines. The fuzzy logic system rule base is derived using heuristics extracted from designed experiments and flight data representing component performance changes due to field service degradation. The fuzzy logic rule based method incorporates both sensed engine parameters that represent non-deteriorated engine operation and fault conditions related to engine performance such as high pressure turbine, high pressure compressor and combustor deterioration. The fuzzy logic system is evaluated using residuals calculated based on both empirical models as inputs. The efficacy of the fuzzy logic system in detecting and diagnosing engine faults is demonstrated using field test data. We also examine performance robustness in the presence of varying levels of sensor noise and measurement errors.
In previous studies, we have extended the conceptual graph model, which is a knowledge representation model belonging to the family of semantic networks, to be able to represent fuzzy values. The basic conceptual grap...
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In previous studies, we have extended the conceptual graph model, which is a knowledge representation model belonging to the family of semantic networks, to be able to represent fuzzy values. The basic conceptual graph model has a logical interpretation in first-order logic. In this paper, we focus on the logical interpretation of the conceptual graph model extended to fuzzy values: we use logical implications stemming from fuzzy logic, so as to extend the logical interpretation of the model to fuzzy values and to comparisons between fuzzy conceptual graphs.
This paper proposes three approaches to classify substation single-line diagrams so it can be used in a power distribution network expansion. With these approaches the expertise shall confront different single-line di...
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This paper proposes three approaches to classify substation single-line diagrams so it can be used in a power distribution network expansion. With these approaches the expertise shall confront different single-line diagrams, so he can choose the best solution to a given problem. This classification is based on reliability, operational flexibility and impact on the environment criteria of each electrical equipment that is part of a substation specification. Simulations were accomplished to establish the best way to stand for the classification criteria through the fuzzy logic use and the approach with the best outcomes in the classification.
Many civil and mechanical systems are in continuous use despite aging and associated potential risk for damage accumulation. Hence, the ability to monitor the structural health of these systems on a real-time basis is...
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Many civil and mechanical systems are in continuous use despite aging and associated potential risk for damage accumulation. Hence, the ability to monitor the structural health of these systems on a real-time basis is becoming very important. This paper describes a practical real-time structural health monitoring system using soft computing tools and its application to the structural health monitoring of a steel bridge located in Missouri. Vibration data collected from this bridge was processed and fed to the fuzzy logic decision system. The fuzzy logic decision system makes use of fuzzy clustering to determine the possible presence of damage in the bridge. A neural network prediction system which makes use of backpropagation algorithm predicts the amount of actual damage in the members which were predicted damaged by the fuzzy logic.
The most important application of fuzzy logic is designing controllers. Fuzzy logic controllers (FLC) are much easier to design than non-linear controllers of similar capabilities. The rules that a designer needs to c...
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The most important application of fuzzy logic is designing controllers. Fuzzy logic controllers (FLC) are much easier to design than non-linear controllers of similar capabilities. The rules that a designer needs to create are often based on their current experience and knowledge. Conventional FLCs use Center of Gravity or Mean of Maxima defuzzification methods, though other methods have been studied. This paper compares the efficiency of many different models of the defuzzification process. The goal is to examine the accuracy of the output data and the amount of processing time required. A simple controller that backs a truck up to a gate is used in the study. All of the variables are granulated with trapezoidal fuzzy numbers. Some of the defuzzification methods examined are Fast Center of Gravity, Mean of Maxima, True Center of Gravity and various new methods that have shown promise in application.
A novel approach is proposed to combine the strengths of GA and GP to optimize rule sets and membership functions of fuzzy systems in a co-evolutionary strategy in order to avoid the problem of dual representation in ...
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A novel approach is proposed to combine the strengths of GA and GP to optimize rule sets and membership functions of fuzzy systems in a co-evolutionary strategy in order to avoid the problem of dual representation in fuzzy systems. The novelty of proposed algorithm is twofold. One is that GP is used for the structural part (Rule sets) and GA for the string part (Membership functions). The goal is to reduce/eliminate the problem of competing conventions by co-evolving pieces of the problem separately and then in combination. Second is exploiting the synergism between rules sets and membership functions by imitating the effect of "matching" and friendship in cooperating teams of humans, thereby significantly reducing the number of function evaluations necessary for evolution. The method is applied to a chaotic time series prediction problem and compared with the standard fuzzy table look-up scheme. demonstrate several significant improvements with the proposed approach; specifically, four times higher fitness and more steady fitness improvements as compared with epochal improvements observed in GP.
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