13 research outputs found
Clearing Restarting Automata
RestartovacĂ automaty byly navrĹľeny jako model pro redukÄŤnĂ analĂ˝zu, která pĹ™edstavuje lingvisticky motivovanou metodu pro kontrolu korektnosti vÄ›ty. CĂlem práce je studovat omezenÄ›jšà modely restartovacĂch automatĹŻ, kterĂ© smĂ vymazat podĹ™etÄ›zec nebo jej nahradit speciálnĂm pomocnĂ˝m symbolem, jenom na základÄ› omezenĂ©ho lokálnĂho kontextu tohoto podĹ™etÄ›zce. Tyto restartovacĂ automaty se nazĂ˝vajĂ clearing restarting automata. V práci jsou taktĂ©Ĺľ zkoumány uzávÄ›rovĂ© vlastnosti tÄ›chto automatĹŻ, jejich vztah k Chomskeho hierarchii a moĹľnosti uÄŤenĂ tÄ›chto automatĹŻ na základÄ› pozitivnĂch a negativnĂch pĹ™ĂkladĹŻ.Restarting automata were introduced as a model for analysis by reduction which is a linguistically motivated method for checking correctness of a sentence. The goal of the thesis is to study more restricted models of restarting automata which based on a limited context can either delete a substring of the current content of its tape or replace a substring by a special symbol, which cannot be overwritten anymore, but it can be deleted later. Such restarting automata are called clearing restarting automata. The thesis investigates the properties of clearing restarting automata, their relation to Chomsky hierarchy and possibilities for machine learning of such automata from positive and negative samples.Department of Software and Computer Science EducationKatedra softwaru a vĂ˝uky informatikyFaculty of Mathematics and PhysicsMatematicko-fyzikálnĂ fakult
Alternative Automata-based Approaches to Probabilistic Model Checking
In this thesis we focus on new methods for probabilistic model checking (PMC) with linear temporal logic (LTL). The standard approach translates an LTL formula into a deterministic ω-automaton with a double-exponential blow up.
There are approaches for Markov chain analysis against LTL with exponential runtime, which motivates the search for non-deterministic automata with restricted forms of non-determinism that make them suitable for PMC. For MDPs, the approach via deterministic automata matches the double-exponential lower bound, but a practical application might benefit from approaches via non-deterministic automata.
We first investigate good-for-games (GFG) automata. In GFG automata one can resolve the non-determinism for a finite prefix without knowing the infinite suffix and still obtain an accepting run for an accepted word. We explain that GFG automata are well-suited for MDP analysis on a theoretic level, but our experiments show that GFG automata cannot compete with deterministic automata.
We have also researched another form of pseudo-determinism, namely unambiguity, where for every accepted word there is exactly one accepting run. We present a polynomial-time approach for PMC of Markov chains against specifications given by an unambiguous BĂĽchi automaton (UBA). Its two key elements are the identification whether the induced probability is positive, and if so, the identification of a state set inducing probability 1.
Additionally, we examine the new symbolic Muller acceptance described in the Hanoi Omega Automata Format, which we call Emerson-Lei acceptance. It is a positive Boolean formula over unconditional fairness constraints. We present a construction of small deterministic automata using Emerson-Lei acceptance. Deciding, whether an MDP has a positive maximal probability to satisfy an Emerson-Lei acceptance, is NP-complete. This fact has triggered a DPLL-based algorithm for deciding positiveness
LIPIcs, Volume 261, ICALP 2023, Complete Volume
LIPIcs, Volume 261, ICALP 2023, Complete Volum
Actes de l'Ecole d'Eté Temps Réel 2005 - ETR'2005
Pdf des actes disponible à l'URL http://etr05.loria.fr/Le programme de l'Ecole d'été Temps Réel 2005 est construit autour d'exposés de synthèse donnés par des spécialistes du monde industriel et universitaire qui permettront aux participants de l'ETR, et notamment aux doctorants, de se forger une culture scientifique dans le domaine. Cette quatrième édition est centrée autour des grands thèmes d'importance dans la conception des systèmes temps réel : Langages et techniques de description d'architectures, Validation, test et preuve par des approches déterministes et stochastiques, Ordonnancement et systèmes d'exploitation temps réel, Répartition, réseaux temps réel et qualité de service
Virtual Neanderthals : a study in agent-based modelling Late Pleistocene hominins in western Europe
This study presents an agent-based simulation model
exploring the patterns of presence and absence of Late Pleistocene
Neanderthals in western Europe. HomininSpace implements a parameterized
generic demographic and social model of hominin dispersal while avoiding
parameter value biases and explicitly modelled handicaps. Models are
simulated through time within a high-resolution environment where
reconstructed temperatures and precipitation levels influence the carrying
capacity of the landscape. Model parameter values are assigned and varied
automatically while optimizing the match with Neanderthal archaeology using a
Genetic Algorithm (GA) inspired by the processes of natural selection. The
system is able to traverse the huge parameter space that is created by the
complete set of all possible parameter value combinations to find those
values that will result in a simulation that matches well with archaeological
data in the form of radiometrically obtained presence data.
Human Origin