30,107 research outputs found
State Identification for Labeled Transition Systems with Inputs and Outputs
For Finite State Machines (FSMs) a rich testing theory has been developed to
discover aspects of their behavior and ensure their correct functioning.
Although this theory is widely used, e.g., to check conformance of protocol
implementations, its applicability is limited by restrictions of the FSM
framework: the fact that inputs and outputs alternate in an FSM, and outputs
are fully determined by the previous input and state. Labeled Transition
Systems with inputs and outputs (LTSs), as studied in ioco testing theory,
provide a richer framework for testing component oriented systems, but lack the
algorithms for test generation from FSM theory.
In this article, we propose an algorithm for the fundamental problem of state
identification during testing of LTSs. Our algorithm is a direct generalization
of the well-known algorithm for computing adaptive distinguishing sequences for
FSMs proposed by Lee & Yannakakis. Our algorithm has to deal with so-called
compatible states, states that cannot be distinguished in case of an
adversarial system-under-test. Analogous to the result of Lee & Yannakakis, we
prove that if an (adaptive) test exists that distinguishes all pairs of
incompatible states of an LTS, our algorithm will find one. In practice, such
adaptive tests typically do not exist. However, in experiments with an
implementation of our algorithm on an industrial benchmark, we find that tests
produced by our algorithm still distinguish more than 99% of the incompatible
state pairs
Distinguishing sequences for partially specified FSMs
Distinguishing Sequences (DSs) are used inmany Finite State Machine (FSM) based test techniques. Although Partially Specified FSMs (PSFSMs) generalise FSMs, the computational complexity of constructing Adaptive and Preset DSs (ADSs/PDSs) for PSFSMs has not been addressed. This paper shows that it is possible to check the existence of an ADS in polynomial time but the corresponding problem for PDSs is PSPACE-complete. We also report on the results of experiments with benchmarks and over 8 * 106 PSFSMs. Ā© 2014 Springer International Publishing
Learning Markov Decision Processes for Model Checking
Constructing an accurate system model for formal model verification can be
both resource demanding and time-consuming. To alleviate this shortcoming,
algorithms have been proposed for automatically learning system models based on
observed system behaviors. In this paper we extend the algorithm on learning
probabilistic automata to reactive systems, where the observed system behavior
is in the form of alternating sequences of inputs and outputs. We propose an
algorithm for automatically learning a deterministic labeled Markov decision
process model from the observed behavior of a reactive system. The proposed
learning algorithm is adapted from algorithms for learning deterministic
probabilistic finite automata, and extended to include both probabilistic and
nondeterministic transitions. The algorithm is empirically analyzed and
evaluated by learning system models of slot machines. The evaluation is
performed by analyzing the probabilistic linear temporal logic properties of
the system as well as by analyzing the schedulers, in particular the optimal
schedulers, induced by the learned models.Comment: In Proceedings QFM 2012, arXiv:1212.345
Generating Complete and Finite Test Suite for ioco: Is It Possible?
Testing from Input/Output Transition Systems has been intensely investigated.
The conformance between the implementation and the specification is often
determined by the so-called ioco-relation. However, generating tests for ioco
is usually hindered by the problem of conflicts between inputs and outputs.
Moreover, the generation is mainly based on nondeterministic methods, which may
deliver complete test suites but require an unbounded number of executions. In
this paper, we investigate whether it is possible to construct a finite test
suite which is complete in a predefined fault domain for the classical ioco
relation even in the presence of input/output conflicts. We demonstrate that it
is possible under certain assumptions about the specification and
implementation, by proposing a method for complete test generation, based on a
traditional method developed for FSM.Comment: In Proceedings MBT 2014, arXiv:1403.704
Learning phase transitions from dynamics
We propose the use of recurrent neural networks for classifying phases of
matter based on the dynamics of experimentally accessible observables. We
demonstrate this approach by training recurrent networks on the magnetization
traces of two distinct models of one-dimensional disordered and interacting
spin chains. The obtained phase diagram for a well-studied model of the
many-body localization transition shows excellent agreement with previously
known results obtained from time-independent entanglement spectra. For a
periodically-driven model featuring an inherently dynamical time-crystalline
phase, the phase diagram that our network traces in a previously-unexplored
regime coincides with an order parameter for its expected phases.Comment: 5 pages + 3 fig, appendix + 5 fi
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