DSpace Collection: EUSTYL'98
http://hdl.handle.net/2099/2069
EUSTYL'982014-08-28T15:56:15ZEditorial [8th. Spanish Congress on Fuzzy Logic and Technology: selection of extended new versions of papers]
http://hdl.handle.net/2099/3680
Title: Editorial [8th. Spanish Congress on Fuzzy Logic and Technology: selection of extended new versions of papers]
Authors: Burillo López, Pedro; Sobrino Cerdeiriña, Alejandro1999-01-01T00:00:00ZA mixed-signal architecture for high complexity CMOS fuzzy controllers
http://hdl.handle.net/2099/3563
Title: A mixed-signal architecture for high complexity CMOS fuzzy controllers
Authors: Navas González, Rafael; Vidal Verdú, Fernando; Rodríguez-Vázquez, Ángel
Abstract: Analog circuits provide better area/power efficiency than their digital counterparts for low-medium precision requirements [1]. This limit in precision, as well as the lack of design tools when compared to the
digital approach, imposes a limit of complexity, hence fuzzy analog controllers are usually oriented to fast low-power systems with low-medium complexity. This paper presents a strategy to preserve most
of the advantages of an analog implementation, while allowing a notorious increment of the system complexity.
Such strategy consists in implementing a reduced number of rules, those that really determine the output in a lattice controller, which we call analog core, then this core is dynamically programmed to
perform the computation related to a specific rule set. The data to program the analog core are stored in a memory, and
constitutes the whole knowledge base in a kind of virtual rule set. An example 64-rule,
2-input, 4-bit singleton controller has been designed in a CMOS 0.7$\mu$mm technology to demonstrate the viability
of the architecture. The measured input-output delay is around 500ns for a power consumption of 16mW and a chip area (without pads) of 2.65mm$^2$.1999-01-01T00:00:00ZFast prototyping of computing-oriented fuzzy logic systems
http://hdl.handle.net/2099/3562
Title: Fast prototyping of computing-oriented fuzzy logic systems
Authors: Martínez Torre, José Ignacio; Deschamps, Jean Pierre; Fernández Centeno, Milagros
Abstract: In this paper we propose to explore different dedicated hardware solutions in terms of area-speed trade-offs for computing-oriented fuzzy logic systems in the algorithmic abstraction level that fulfil the application requirements applying high level synthesis techniques. The main benefits of this proposal are the capability of selecting the best implementation for any application not being tied down to a predefined architecture, the use of the required number of hardware units and the reduction of the design cycle time. The results obtained in the control of a maximum power point of a photovoltaic plant are presented as an example.1999-01-01T00:00:00ZFormal Validation of Fuzzy Control Techniques. Perspectives
http://hdl.handle.net/2099/3561
Title: Formal Validation of Fuzzy Control Techniques. Perspectives
Authors: Sala Piqueras, Antonio; Albertos Pérez, Pedro
Abstract: In this paper, a survey of the state of the art and perspectives of two main lines of research in fuzzy control systems is presented: on one hand, the \emph{interpolative-functional line} representing fuzzy systems as parameterized universal function approximators, thus applying nonlinear control and neural network paradigms; on the other hand, a \emph{logic-formal} approach where fuzzy systems are analysed in terms of logic interpretations, exploring validation, consistency and completeness, uncertainty management and knowledge supervision. The former approach is not widely used in the control field, and asserting its possibilities is one of the main motivations of this paper. References in both lines and some abridged results in the second case are cited, in particular some of the author's contributions, to which the interested reader is referred.1999-01-01T00:00:00ZOn the global stability of Takagi-Sugeno general model
http://hdl.handle.net/2099/3560
Title: On the global stability of Takagi-Sugeno general model
Authors: Matía, Fernando; Al-Hadithi, Basil M.; Jiménez, Agustín
Abstract: Global stability of Takagi-Sugeno (T-S) fuzzy model is presented. First, stability conditions for T-S fuzzy model presented by Tanaka and Sugeno are reviewed. Second, new theorems for the stability of the general form of T-S model is derived in the sense of Lyapunov.
The T-S model we studied includes a linear equation with a constant parameter in the consequent part of each rule while other authors have analyzed the model with no constant term, which does not represent a real system. This in turn will impose restrictions on the stability conditions derived in this field. An example is presented to illustrate the new suggested condition.1999-01-01T00:00:00ZInference of fuzzy regular grammars from examples
http://hdl.handle.net/2099/3559
Title: Inference of fuzzy regular grammars from examples
Authors: Fortes Ruiz, Inmaculada; Morales Bueno, Rafael; Pérez de la Cruz Molina, José Luís; Triguero Ruiz, Francisco; Comino, M. A.
Abstract: Let us consider the following situation: An oracle provides us with a finite set of examples considered as words belonging to a regular language. This oracle is not available again. In this paper we study a new and general inference algorithm of fuzzy regular grammars based on this set of words. This algorithm is created by adapting a process discovery method. The main issues in the adaptation are the development of a fuzzy version, the assignation of membership degrees to each production in the grammar, and the treatment of consecutive repeated symbols. In addition to this inference algorithm we present a practical use for automatically generating artistic designs. Specifically, we have collected a set of paintings by Piet Mondrian (1872-1944) and obtained new Mondrian-style paintings. To achieve this, we designed a code to transform the paintings into strings and also to carry out the reverse conversion. We view these strings, which represent the paintings, as words belonging to a regular language and from this finite set of examples infer a fuzzy regular grammar. The entire process has been implemented and some new paintings from the inference algorithm have been obtained. An art expert has judged that these computer-generated paintings are fully in the spirit of those painted by Mondrian.1999-01-01T00:00:00ZMethod of least squares applied to the generalized modus ponens with interval-valued fuzzy sets
http://hdl.handle.net/2099/3558
Title: Method of least squares applied to the generalized modus ponens with interval-valued fuzzy sets
Authors: Agustench Cotilla, Eduard; Bustince Sola, Humberto Nicanor; Mohedano Salillas, Mª Victoria
Abstract: Firstly we present a geometric interpretation
of interval-valued fuzzy sets. Secondly, we apply the method of least squares to the fuzzy inference rules when working with
these sets. We begin approximating the lower and upper extremes of the membership intervals to axb type functions by means of the method of least squares. Then we analyze a technique for evaluating the conclusion of the generalized modus ponens and we verify the fulfillment of Fukami and alumni axioms [9].1999-01-01T00:00:00ZOn the learning of weights in some aggregation operators: the weighted mean and OWA operators
http://hdl.handle.net/2099/3557
Title: On the learning of weights in some aggregation operators: the weighted mean and OWA operators
Authors: Torra Ferré, Vicenç
Abstract: We study the determination of weights for two types of aggregation operators: the weighted mean and the OWA operator. We assume that there is at our disposal a set of examples for which the outcome of the
aggregation operator is known. In the case of the OWA operator, we compare the results obtained by our method with another one in the literature. We show that the optimal weighting vector is reached with less cost.1999-01-01T00:00:00ZIdempotent operators on a finite chain
http://hdl.handle.net/2099/3556
Title: Idempotent operators on a finite chain
Authors: Mas Grimalt, Margarita; Torrens Sastre, Joan; Calvo Sánchez, Tomasa; Carbonell Huguet, Marc
Abstract: This work is devoted to find and study
some possible idempotent operators on a finite chain $L$. Specially,
all idempotent operators on $L$ which are associative, commutative and
non-decreasing in each place are characterized. By adding one smoothness
condition, all these
operators reduce to special combinations of Minimum and Maximum.1999-01-01T00:00:00ZPutting together Łukasiewicz and product logics
http://hdl.handle.net/2099/3555
Title: Putting together Łukasiewicz and product logics
Authors: Esteva Massaguer, Francesc; Godo Lacasa, Lluís
Abstract: In this paper we investigate a propositional fuzzy logical system $\L\Pi$ which contains the well-known \L ukasiewicz, Product and G\"{o}del fuzzy logics as sublogics. We define the corresponding algebraic structures, called $\L\Pi$-algebras and prove the following completeness result:
a formula $\varphi$ is provable in the $\L\Pi$ logic iff it is a tautology
for all linear $\L\Pi$-algebras. Moreover, linear $\L\Pi$-algebras are shown to be embeddable in linearly ordered abelian rings with a strong unit and cancellation law.1999-01-01T00:00:00ZA reflection on what is a membership function
http://hdl.handle.net/2099/3554
Title: A reflection on what is a membership function
Authors: Trillas i Gay, Enric; Alsina Català, Claudi
Abstract: This paper is just a first approach to the idea that the membership function $\mu _{P}$ of a fuzzy set labelled $P$ is, basically, a measure on the set of linguistic expressions ``$x$ is $P"$ for each $x$ in the corresponding universe of discourse $X.$ Estimating that the meaning of $P$ (relatively to $X)$ is nothing else than the use of $P$ on $X,$ these ``measures'' seem to
be reached by generalizing to a preordered set the concept of Fuzzy Measure, introduced by M. Sugeno, when the preorder translates the primary use of the predicate $P,$ that is a basic relationship like ``$x$ is less $P$ than $y".$
The paper only deals with predicates whose use is made by means of numerical
characteristics, but those cases on which the characteristics (if they exist) are not of a numerical nature are not considered. By generalizing DeLuca-Termini's sharpened order some typical membership functions are
studied as measures1999-01-01T00:00:00ZTruth and utility in fuzzy logic
http://hdl.handle.net/2099/3553
Title: Truth and utility in fuzzy logic
Authors: Sobrino Cerdeiriña, Alejandro
Abstract: The notion of degree of truth used in fuzzy logic can be interpreted in terms of
partial truth or in terms of utility. By investigating how these interpretations fit in with Tarski's definition of truth, this paper explores some of their implications and their consequences for the foundations and credibility of fuzzy logic.1999-01-01T00:00:00ZSome practical problems in fuzzy sets-based decision support systems
http://hdl.handle.net/2099/3552
Title: Some practical problems in fuzzy sets-based decision support systems
Authors: Sancho Royo, Antonio; Verdegay, José Luis; Vergara-Moreno, Edmundo
Abstract: In this paper some problems arising in the interface between two different areas, Decision Support Systems and Fuzzy Sets and Systems, are considered. The Model-Base Management System of a Decision Support System which involves some fuzziness is considered, and in that context the question, first, of the practical determination of membership functions, second of the management of the fuzziness in some optimisation models, and finally of using fuzzy rules for terminating conventional algorithms are presented, discussed and analyzed. Finally, for the concrete case of the Travelling Salesman Problem, and as an illustration of determination, management and using of fuzzy rules, a new algorithm easy of implementing in the Model-Base Management System of any oriented Decision Support System is shown.1999-01-01T00:00:00ZTowards a fuzzy computability?
http://hdl.handle.net/2099/3551
Title: Towards a fuzzy computability?
Authors: Moraga, Claudio
Abstract: The subject of the present paper is the study of fuzzy computability based on fuzzy Turing machines. Two different models of fuzzy Turing machines will be discussed. It is shown that most work on fuzzy mathematics may be conducted within the frame of classical computability and the rest falls within the area of computability of the reals.1999-01-01T00:00:00ZThe limits of fuzzy logic
http://hdl.handle.net/2099/3550
Title: The limits of fuzzy logic
Authors: Castro Peña, Juan Luis
Abstract: In this paper we try to answer to the following questions: What can be made
by applying fuzzy logic? and What can not be made by applying fuzzy logic?
The question will be analyzed from both theoretical and applied point of view. A (partial) answer will be given for three topics: a) as calculus procedure b) as reasoning mechanism and c) as engineering tool.1999-01-01T00:00:00Z