A new approach for diagnosability analysis of Petri nets using Verifier Nets

In this paper, we analyze the diagnosability properties of labeled Petri nets. We consider the standard notion of diagnosability of languages, requiring that every occurrence of an unobservable fault event be eventually detected, as well as the stronger notion of diagnosability in K steps, where the detection must occur within a fixed bound of K event occurrences after the fault. We give necessary and sufficient conditions for these two notions of diagnosability for both bounded and unbounded Petri nets and then present an algorithmic technique for testing the conditions based on linear programming. Our approach is novel and based on the analysis of the reachability/coverability graph of a special Petri net, called Verifier Net, that is built from the Petri net model of the given system. In the case of systems that are diagnosable in K steps, we give a procedure to compute the bound K. To the best of our knowledge, this is the first time that necessary and sufficient conditions for diagnosability and diagnosability in K steps of labeled unbounded Petri nets are presented

The Status of Lattice Calculations of the Nucleon Structure Functions

We review our progress on the lattice calculation of low moments of both the unpolarised and polarised nucleon structure functions.Comment: 6 pages, contribution to 29th International Symposium on the Theory of Elementary Particles, Buckow, Germany, (29 August - 2 September 1995). 6 pages, Latex, requires espcrc2.sty, epsf.st

Diagnosability of discrete event systems using labeled Petri nets

In this paper, we focus on labeled Petri nets with silent transitions that may either correspond to fault events or to regular unobservable events. We address the problem of deriving a procedure to determine if a given net system is diagnosable, i.e., the occurrence of a fault event may be detected for sure after a finite observation. The proposed procedure is based on our previous results on the diagnosis of discrete-event systems modeled with labeled Petri nets, whose key notions are those of basis markings and minimal explanations, and is inspired by the diagnosability approach for finite state automata proposed by Sampath in 1995. In particular, we first give necessary and sufficient conditions for diagnosability. Then, we present a method to test diagnosability that is based on the analysis of two graphs that depend on the structure of the net, including the faults model, and the initial marking

Geometric Measurement of Topological Susceptibility on Large Lattices

The topological susceptibility of the quenched QCD vacuum is measured on large lattices for three $\beta$ values from $6.0$ to $6.4$. Charges possibly induced by $O(a)$ dislocations are identified and shown to have little effect on the measured susceptibility. As $\beta$ increases, fewer such questionable charges are found. Scaling is checked by examining the ratios of the susceptibility to previously existing values of the rho mass, string tension, F-pi, and lambda-lattice.Comment: LaTeX article, 3 pages, uuencoded compressed tar file, 2 figures included as tex files using axismacros, DVIPS driver required to show figures. Talk presented by Jeffrey Grandy at Lattice 93, Dallas, Texas. Los Alamos Preprint number pendin

Light Quenched Hadron Spectrum and Decay Constants on different Lattices

We present a study of ${\cal O}(2000)$ (quenched) lattice configurations from the APE collaboration, for $6.0\le\beta\le 6.4$ using both the Wilson and the SW-Clover fermion action. We determine the light hadronic spectrum and meson decay constants. We extract the inverse lattice spacing using data at the simulated values of the quark mass. We find an agreement with the experimental data of $\sim 5$ for mesonic masses and $\sim 10$ for baryonic masses and pseudoscalar decay constants. A larger deviation is present for the vector decay constants.Comment: 3 pages, Talk presented at LATTICE96(spectrum

Fault detection for discrete event systems using Petri nets with unobservable transitions

In this paper we present a fault detection approach for discrete event systems using Petri nets. We assume that some of the transitions of the net are unobservable, including all those transitions that model faulty behaviors. Our diagnosis approach is based on the notions of basis marking and justification, that allow us to characterize the set of markings that are consistent with the actual observation, and the set of unobservable transitions whose firing enable it. This approach applies to all net systems whose unobservable subnet is acyclic. If the net system is also bounded the proposed approach may be significantly simplified by moving the most burdensome part of the procedure off-line, thanks to the construction of a graph, called the basis reachability graph

Les attentats du 11 septembre. Émotion et raison dans la presse en France et en Italie

L’analyse de la mise en discours de l’émotion dans les éditoriaux à la suite de l’opération terroriste du 11 septembre permet de dégager deux attitudes. Dans la phase immédiate de l’après-attentat, un sentiment de vulnérabilité engendre la prise de conscience d’une profonde appartenance, alors que la distance du drame impose un appel à la rationalité pour refonder la solidarité sur les valeurs démocratiques.The present analysis deals with emotion in discourse with a particular reference to the editorials that were published after the terrorist attacks against the United States. There were two types of reactions in the Press : immediately following the attacks, an impression of vulnerability conjured up a sense of identity and solidarity. After this first emotional reaction, there was an appeal to rationality in which solidarity is based on democratic values.El análisis de la puesta en discurso de la emoción en los editoriales consecutivos al 11 de setiembre permite destacar dos atitudes. En una primera fase siguiendo el ataque se desarrolló un sentimiento de vulnerabiliad desencadendando pues una toma de conciencia de una pertenencia cuando la distancia del drama imponía un llamado a la conciencia para fundar de nuevo la solidaridad sobre valores democráticos

Diagnosability Analysis of Labeled Time Petri Net Systems

In this paper, we focus on two notions of diagnosability for labeled Time Petri net (PN) systems: K-diagnosability implies that any fault occurrence can be detected after at most K observations, while τ-diagnosability implies that any fault occurrence can be detected after at most τ time units. A procedure to analyze such properties isprovided.The proposedapproach uses the Modified State Class Graph, a graph the authors recently introduced for the marking estimation of labeled Time PN systems,which providesan exhaustive description of the system behavior. A preliminary diagnosabilty analysis of the underlying logic system based on classical approaches taken from the literature is required. Then, the solution of some linear programming problems should be performed to take into account the timing constraints associated with transitions

High statistics calculations of quenched QCD spectrum using various quark sources

We present the results for the hadron spectrum calculated on 400 configurations using point source, wall source and 8-cubic sources, in quenched QCD with Wilson fermions at $\beta=6.0$ and $K=0.155$ on a $24^3 \times 54$ lattice. The results for the ground state masses obtained with three types of quark sources agree well with each other. Masses of the first excited states appear consistent with experimental values within large errors.Comment: 3 pages, 2 postscript figures, to appear in the Proceedings of LATTICE 93, Dallas, USA; preprint UTHEP-26

La construction de l’ethos présidentiel dans le débat télévisé français

À travers une approche de l’interaction médiatique reposant sur la théorie de l’action et de l’argumentation, nous nous proposons d’observer, au cours de trois émissions diffusées dans la période de cristallisation de la campagne française pour la présidentielle (mars 2007), l’élaboration de l’ethos discursif des trois candidats majeurs, les procédés linguistiques qui les distinguent et le genre de relation interpersonnelle qui se crée entre le journaliste et la personnalité politique.This article applies media interaction approach arising from the theory of action and argumentative component to three television programmes broadcast during a crucial stage of the French presidential election campaign (March 2007) with a focus on how the discursive ethos of the three major candidates is elaborated, how one can tell them apart by their linguistic process and how an interpersonal relation of a kind is built up between these politicians and the journalist interviewing them.Interesándose a la interacción mediática sobre la base de la teoría de la acción y de la argumentación, nos proponemos observar al lo largo de tres emisiones emitidas durante el periodo de la cristalización de las elecciones presidenciales francesas (marzo 2007), la elaboración del ethos discursivo de los tres mayores candidatos, los procedimientos linguísticos que los distinguen y el tipo de relaciones personales que se tejen entre el periodista y la personalidad política