9,696 research outputs found
Formal and Informal Methods for Multi-Core Design Space Exploration
We propose a tool-supported methodology for design-space exploration for
embedded systems. It provides means to define high-level models of applications
and multi-processor architectures and evaluate the performance of different
deployment (mapping, scheduling) strategies while taking uncertainty into
account. We argue that this extension of the scope of formal verification is
important for the viability of the domain.Comment: In Proceedings QAPL 2014, arXiv:1406.156
A uniform framework for modelling nondeterministic, probabilistic, stochastic, or mixed processes and their behavioral equivalences
Labeled transition systems are typically used as behavioral models of concurrent processes, and the labeled transitions define the a one-step state-to-state reachability relation. This model can be made generalized by modifying the transition relation to associate a state reachability distribution, rather than a single target state, with any pair of source state and transition label. The state reachability distribution becomes a function mapping each possible target state to a value that expresses the degree of one-step reachability of that state. Values are taken from a preordered set equipped with a minimum that denotes unreachability. By selecting suitable preordered sets, the resulting model, called ULTraS from Uniform Labeled Transition System, can be specialized to capture well-known models of fully nondeterministic processes (LTS), fully
probabilistic processes (ADTMC), fully stochastic processes (ACTMC), and of nondeterministic and probabilistic (MDP) or nondeterministic and stochastic (CTMDP) processes. This uniform treatment of different behavioral models extends to behavioral equivalences. These can be defined on ULTraS by relying on appropriate measure functions that expresses the degree of reachability of a set of states when performing
single-step or multi-step computations. It is shown that the specializations of bisimulation, trace, and testing
equivalences for the different classes of ULTraS coincide with the behavioral equivalences defined in the literature over traditional models
Lipschitz Robustness of Finite-state Transducers
We investigate the problem of checking if a finite-state transducer is robust
to uncertainty in its input. Our notion of robustness is based on the analytic
notion of Lipschitz continuity --- a transducer is K-(Lipschitz) robust if the
perturbation in its output is at most K times the perturbation in its input. We
quantify input and output perturbation using similarity functions. We show that
K-robustness is undecidable even for deterministic transducers. We identify a
class of functional transducers, which admits a polynomial time
automata-theoretic decision procedure for K-robustness. This class includes
Mealy machines and functional letter-to-letter transducers. We also study
K-robustness of nondeterministic transducers. Since a nondeterministic
transducer generates a set of output words for each input word, we quantify
output perturbation using set-similarity functions. We show that K-robustness
of nondeterministic transducers is undecidable, even for letter-to-letter
transducers. We identify a class of set-similarity functions which admit
decidable K-robustness of letter-to-letter transducers.Comment: In FSTTCS 201
On Zone-Based Analysis of Duration Probabilistic Automata
We propose an extension of the zone-based algorithmics for analyzing timed
automata to handle systems where timing uncertainty is considered as
probabilistic rather than set-theoretic. We study duration probabilistic
automata (DPA), expressing multiple parallel processes admitting memoryfull
continuously-distributed durations. For this model we develop an extension of
the zone-based forward reachability algorithm whose successor operator is a
density transformer, thus providing a solution to verification and performance
evaluation problems concerning acyclic DPA (or the bounded-horizon behavior of
cyclic DPA).Comment: In Proceedings INFINITY 2010, arXiv:1010.611
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