1999, Vol. VI, Núm. 2-3
http://hdl.handle.net/2099/2069
EUSTYL'98Fri, 31 Jul 2015 01:22:25 GMT2015-07-31T01:22:25ZEditorial [8th. Spanish Congress on Fuzzy Logic and Technology: selection of extended new versions of papers]
http://hdl.handle.net/2099/3680
Editorial [8th. Spanish Congress on Fuzzy Logic and Technology: selection of extended new versions of papers]
Burillo López, Pedro; Sobrino Cerdeiriña, Alejandro
Fri, 01 Jan 1999 00:00:00 GMThttp://hdl.handle.net/2099/36801999-01-01T00:00:00ZA mixed-signal architecture for high complexity CMOS fuzzy controllers
http://hdl.handle.net/2099/3563
A mixed-signal architecture for high complexity CMOS fuzzy controllers
Navas González, Rafael; Vidal Verdú, Fernando; Rodríguez-Vázquez, Ángel
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$^2$.
Fri, 01 Jan 1999 00:00:00 GMThttp://hdl.handle.net/2099/35631999-01-01T00:00:00ZFast prototyping of computing-oriented fuzzy logic systems
http://hdl.handle.net/2099/3562
Fast prototyping of computing-oriented fuzzy logic systems
Martínez Torre, José Ignacio; Deschamps, Jean Pierre; Fernández Centeno, Milagros
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.
Fri, 01 Jan 1999 00:00:00 GMThttp://hdl.handle.net/2099/35621999-01-01T00:00:00ZFormal Validation of Fuzzy Control Techniques. Perspectives
http://hdl.handle.net/2099/3561
Formal Validation of Fuzzy Control Techniques. Perspectives
Sala Piqueras, Antonio; Albertos Pérez, Pedro
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.
Fri, 01 Jan 1999 00:00:00 GMThttp://hdl.handle.net/2099/35611999-01-01T00:00:00ZOn the global stability of Takagi-Sugeno general model
http://hdl.handle.net/2099/3560
On the global stability of Takagi-Sugeno general model
Matía, Fernando; Al-Hadithi, Basil M.; Jiménez, Agustín
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.
Fri, 01 Jan 1999 00:00:00 GMThttp://hdl.handle.net/2099/35601999-01-01T00:00:00ZInference of fuzzy regular grammars from examples
http://hdl.handle.net/2099/3559
Inference of fuzzy regular grammars from examples
Fortes Ruiz, Inmaculada; Morales Bueno, Rafael; Pérez de la Cruz Molina, José Luís; Triguero Ruiz, Francisco; Comino, M. A.
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.
Fri, 01 Jan 1999 00:00:00 GMThttp://hdl.handle.net/2099/35591999-01-01T00:00:00ZMethod of least squares applied to the generalized modus ponens with interval-valued fuzzy sets
http://hdl.handle.net/2099/3558
Method of least squares applied to the generalized modus ponens with interval-valued fuzzy sets
Agustench Cotilla, Eduard; Bustince Sola, Humberto Nicanor; Mohedano Salillas, Mª Victoria
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].
Fri, 01 Jan 1999 00:00:00 GMThttp://hdl.handle.net/2099/35581999-01-01T00:00:00ZOn the learning of weights in some aggregation operators: the weighted mean and OWA operators
http://hdl.handle.net/2099/3557
On the learning of weights in some aggregation operators: the weighted mean and OWA operators
Torra Ferré, Vicenç
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.
Fri, 01 Jan 1999 00:00:00 GMThttp://hdl.handle.net/2099/35571999-01-01T00:00:00ZIdempotent operators on a finite chain
http://hdl.handle.net/2099/3556
Idempotent operators on a finite chain
Mas Grimalt, Margarita; Torrens Sastre, Joan; Calvo Sánchez, Tomasa; Carbonell Huguet, Marc
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.
Fri, 01 Jan 1999 00:00:00 GMThttp://hdl.handle.net/2099/35561999-01-01T00:00:00ZPutting together Łukasiewicz and product logics
http://hdl.handle.net/2099/3555
Putting together Łukasiewicz and product logics
Esteva Massaguer, Francesc; Godo Lacasa, Lluís
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.
Fri, 01 Jan 1999 00:00:00 GMThttp://hdl.handle.net/2099/35551999-01-01T00:00:00Z