In this paper, we present a methodology for automatic diagnosis of systems characterized by continuous signals. For each condition considered, the methodology requires the development of an alphabet of signal primitives, and a set of hierarchical fuzzy automatons (HFAs). Each alphabet is adaptively obtained by training an adaptive resonance theory (ART2) architecture with signal segments from a...

Light curves of eight BL Lac objects in the BVRI bands have been analyzed. All of the objects tend to be bluer when brighter. However spectral slope changes differ quantitatively from those of a sample of QSOs analyzed in a previous paper (Trevese & Vagnetti 2002) and appear consistent with a different nature of the optical continuum. A simple model representing the variability of a synchrotron...

In this paper we combine determinization and state reduction methods into two-in-one algorithms that simultaneously perform determinization and state reduction. These algorithms perform better than all previous determinization algorithms for fuzzy finite automata, developed by Bělohlávek [Inform Sciences 143 (2002) 205–209], Li and Pedrycz [Fuzzy Set Syst 156 (2005) 68–92], Ignjatović et al. [I...

We consider weighted finite automata over strong bimonoids, where these weight structures can be considered as semirings which might lack distributivity. Then, in general, the well-known run semantics, initial algebra semantics, and transition semantics of an automaton are different. We prove an algebraic characterization for the initial algebra semantics in terms of stable finitely generated s...

Light curves of eight BL Lac objects in the BVRI bands have been analyzed. All of the objects tend to be bluer when brighter. However spectral slope changes differ quantitatively from those of a sample of QSOs analyzed in a previous paper (Trevese & Vagnetti 2002) and appear consistent with a different nature of the optical continuum. A simple model representing the variability of a synchrotron...

Polarization measurements are presented for 52 radio-loud QSOs and BL Lac objects. For 9 highly polarized (p> 3%) AGN, these are the first published polarization measurements. Of these 9, 7 are highly-polarized QSOs (HPQs), one is a BL Lac object and another is a likely BL Lac object. Polarization variability is confirmed for some of these new and previously known highly-polarized AGN. While 6 ...

A cover automaton of a finite language L is a finite automaton that accepts all words in L and possibly other words that are longer than any word in L. An algorithm for constructing a minimal cover automaton of a finite language L is given in a recent paper. This paper goes a step further by proposing a procedure for constructing all minimal cover automata of a given finite language L. The conc...

We introduce MK-fuzzy automata over a bimonoid K which is related to the fuzzification of the McCarthy-Kleene logic. Our automata are inspired by, and intend to contribute to, practical applications being in development in a project on runtime network monitoring based on predicate logic. We investigate closure properties of the class of recognizableMK-fuzzy languages accepted by MKfuzzy automat...

The main purpose of this work is to understand some limitations introduced by the classical definitions of cellnlar automata (CA). To this end, we have defined a new model of CAs (fuzzy CAs) which allows the observation of interesting "chaotic" properties of elementary CAs. To date neither a formal nor a precise definition of "chaos" in CAs exists; we believe that the proposed model provides a ...