scholarly journals USING AN EXTENSIONS OF CTL* FOR SPECIFICATION AND VERIFICATION OF SEQUENTIAL REACTIVE SYSTEMS

2020 ◽  
Author(s):  
Anton Romanovich Gnatenko ◽  
◽  
Vladimir Anatolyevoch Zakharov ◽  
Keyword(s):  
Model Checking ◽  
Formal Model ◽  
Reactive Systems ◽  
Expressive Power ◽  
Binary Relations ◽  
Temporal Logics ◽  
Finite State Transducers ◽  
Control Signals ◽  
Data Control ◽  
Finite State

Sequential reactive systems such as controllers, device drivers, computer interpreters operate with two data streams and transform input streams of data (control signals, instructions) into output streams of control signals (instructions, data). Finite state transducers are widely used as an adequate formal model for information processing systems of this kind. Since runs of transducers develop over time, temporal logics, obviously, could be used as both simple and expressive formalism for specifying the behavior of sequential reactive systems. However, the conventional applied temporal logics (LTL, CTL) do not suit this purpose well, since their formulae are interpreted over omega-languages, whereas the behavior of transducers are represented by binary relations on infinite sequences, i.e. omega-transductions. To provide temporal logic with the ability to take into account this general feature of the behavior of reactive systems, we introduced new extensions of this logic. Two distinguished features characterize these extension: 1) temporal operators are parameterized by sets of streams (languages) admissible for input, and 2) sets (languages) of expected output streams are used as basic predicates. In the previous series of works we studied the expressive power and the model checking problem for Reg-LTL and Reg-CTL which are such extensions of LTL and CTL where the languages mentioned above are regular ones. We discovered that such an extension of temporal logics increases their expressive capability though retains the decidability of the model checking problem. Our next step in the systematic study of expressive and algorithmic properties of new extensions temporal logics is the analysis of the model checking problem for finite state transducers against Reg-CTL* formulae. In this paper we develop a model checking algorithm for Reg-CTL* and show that this problem is in ExpSpace.

scholarly journals On the Model Checking Problem for Some Extension of CTL*

2020 ◽  
Vol 27 (4) ◽  
pp. 428-441
Author(s):  
Anton Romanovich Gnatenko ◽  
Vladimir Anatolyevich Zakharov
Keyword(s):  
Model Checking ◽  
Temporal Logic ◽  
Reactive Systems ◽  
Expressive Power ◽  
Binary Relations ◽  
Temporal Logics ◽  
Distinctive Features ◽  
Verification Problem ◽  
Finite State ◽  
Infinite Sequences

Sequential reactive systems include programs and devices that work with two streams of data and convert input streams of data into output streams. Such information processing systems include controllers, device drivers, computer interpreters. The result of the operation of such computing systems are infinite sequences of pairs of events of the request-response type, and, therefore, finite transducers are most often used as formal models for them. The behavior of transducers is represented by binary relations on infinite sequences, and so, traditional applied temporal logics (like HML, LTL, CTL, mu-calculus) are poorly suited as specification languages, since omega-languages, not binary relations on omega-words are used for interpretation of their formulae. To provide temporal logics with the ability to define properties of transformations that characterize the behavior ofreactive systems, we introduced new extensions ofthese logics, which have two distinctive features: 1) temporal operators are parameterized, and languages in the input alphabet oftransducers are used as parameters; 2) languages in the output alphabet oftransducers are used as basic predicates. Previously, we studied the expressive power ofnew extensions Reg-LTL and Reg-CTL ofthe well-known temporal logics oflinear and branching time LTL and CTL, in which it was allowed to use only regular languages for parameterization of temporal operators and basic predicates. We discovered that such a parameterization increases the expressive capabilities oftemporal logic, but preserves the decidability of the model checking problem. For the logics mentioned above, we have developed algorithms for the verification of finite transducers. At the next stage of our research on the new extensions of temporal logic designed for the specification and verification of sequential reactive systems, we studied the verification problem for these systems using the temporal logic Reg-CTL*, which is an extension ofthe Generalized Computational Tree Logics CTL*. In this paper we present an algorithm for checking the satisfiability of Reg-CTL* formulae on models of finite state transducers and show that this problem belongs to the complexity class ExpSpace.

scholarly journals On the Satisfiability and Model Checking for one Parameterized Extension of Linear-time Temporal Logic

2021 ◽  
Vol 28 (4) ◽  
pp. 356-371
Author(s):  
Anton Romanovich Gnatenko ◽  
Vladimir Anatolyevich Zakharov
Keyword(s):  
Model Checking ◽  
Temporal Logic ◽  
Linear Time ◽  
Complete Solution ◽  
Reactive Systems ◽  
Expressive Power ◽  
Regular Languages ◽  
Specification Languages ◽  
Temporal Logics ◽  
Emptiness Problem

Sequential reactive systems are computer programs or hardware devices which process the flows of input data or control signals and output the streams of instructions or responses. When designing such systems one needs formal specification languages capable of expressing the relationships between the input and output flows. Previously, we introduced a family of such specification languages based on temporal logics $LTL$, $CTL$ and $CTL^*$ combined with regular languages. A characteristic feature of these new extensions of conventional temporal logics is that temporal operators and basic predicates are parameterized by regular languages. In our early papers, we estimated the expressive power of the new temporal logic $Reg$-$LTL$ and introduced a model checking algorithm for $Reg$-$LTL$, $Reg$-$CTL$, and $Reg$-$CTL^*$. The main issue which still remains unclear is the complexity of decision problems for these logics. In the paper, we give a complete solution to satisfiability checking and model checking problems for $Reg$-$LTL$ and prove that both problems are Pspace-complete. The computational hardness of the problems under consideration is easily proved by reducing to them the intersection emptyness problem for the families of regular languages. The main result of the paper is an algorithm for reducing the satisfiability of checking $Reg$-$LTL$ formulas to the emptiness problem for Buchi automata of relatively small size and a description of a technique that allows one to check the emptiness of the obtained automata within space polynomial of the size of input formulas.

scholarly journals On the Expressive Power of Some Extensions of Linear Temporal Logic

2018 ◽  
Vol 25 (5) ◽  
pp. 506-524
Author(s):  
Anton Gnatenko ◽  
Vladimir Zakharov
Keyword(s):  
Temporal Logic ◽  
Reactive Systems ◽  
Expressive Power ◽  
Linear Temporal Logic ◽  
Reactive System ◽  
Formal Specifications ◽  
Control Signals ◽  
Finite State ◽  
Finite State Transducer ◽  
Output Alphabet

One of the most simple models of computation which is suitable for representation of reactive systems behaviour is a finite state transducer which operates over an input alphabet of control signals and an output alphabet of basic actions. The behaviour of such a reactive system displays itself in the correspondence between flows of control signals and compositions of basic actions performed by the system. We believe that the behaviour of this kind requires more suitable and expressive means for formal specifications than the conventionalLT L. In this paper, we define some new (as far as we know) extensionLP-LT Lof Linear Temporal Logic specifically intended for describing the properties of transducers computations. In this extension the temporal operators are parameterized by sets of words (languages) which represent distinguished flows of control signals that impact on a reactive system. Basic predicates in our variant of the temporal logic are also languages in the alphabet of basic actions of a transducer; they represent the expected response of the transducer to the specified environmental influences. In our earlier papers, we considered a model checking problem forLP-LT LandLP-CT Land showed that this problem has effective solutions. The aim of this paper is to estimate the expressive power ofLP-LT Lby comparing it with some well known logics widely used in the computer science for specification of reactive systems behaviour. We discovered that a restricted variant LP-1-LT Lof our logic is more expressive thanLTLand another restricted variantLP-n-LT Lhas the same expressive power as monadic second order logic S1S.

scholarly journals Model checking usage policies

2014 ◽  
Vol 25 (3) ◽  
pp. 710-763 ◽  
Author(s):  
MASSIMO BARTOLETTI ◽  
PIERPAOLO DEGANO ◽  
GIAN LUIGI FERRARI ◽  
ROBERTO ZUNINO
Keyword(s):  
Model Checking ◽  
Polynomial Time ◽  
Real World ◽  
Formal Model ◽  
Expressive Power ◽  
Finite State Automata ◽  
Time Model ◽  
Real World Applications ◽  
Finite State ◽  
Resource Creation

We study usage automata, a formal model for specifying policies on the usage of resources. Usage automata extend finite state automata with some additional features, parameters and guards, that improve their expressivity. We show that usage automata are expressive enough to model policies of real-world applications. We discuss their expressive power, and we prove that the problem of telling whether a computation complies with a usage policy is decidable. The main contribution of this paper is a model checking technique for usage automata. The model is that of usages, i.e. basic processes that describe the possible patterns of resource access and creation. In spite of the model having infinite states, because of recursion and resource creation, we devise a polynomial-time model checking technique for deciding when a usage complies with a usage policy.

scholarly journals Multi-Sequential Word Relations

2018 ◽  
Vol 29 (02) ◽  
pp. 271-295 ◽  
Author(s):  
Ismaël Jecker ◽  
Emmanuel Filiot
Keyword(s):  
Rational Function ◽  
Finite Union ◽  
Binary Relations ◽  
Rational Relation ◽  
Finite State Transducers ◽  
Finite State

Rational relations are binary relations of finite words that are realised by non-deterministic finite state transducers (NFT). A multi-sequential relation is a rational relation which is equal to a finite union of (graphs) of partial sequential functions, i.e. functions realised by input-deterministic transducers. The particular case of multi-sequential functions was studied by Choffrut and Schützenberger who proved that given a rational function (as a transducer), it is decidable whether it is multi-sequential. Their procedure is based on an effective characterisation of unambiguous transducers that do not define multi-sequential functions, that we call the fork property. In this paper, we show that the fork property also characterises the class of transducers that do not define multi-sequential relations. Moreover, we prove that the fork property can be decided in PTime. This leads to a PTime procedure which, given a transducer, decides whether it defines a multi-sequential relation.

scholarly journals Automatic verification of timed concurrent constraint programs

2006 ◽  
Vol 6 (3) ◽  
pp. 265-300 ◽  
Author(s):  
MORENO FALASCHI ◽  
ALICIA VILLANUEVA
Keyword(s):  
Model Checking ◽  
Infinite Number ◽  
Reactive Systems ◽  
Finite Model ◽  
Computation Model ◽  
Huge Number ◽  
Finite State ◽  
Infinite State Systems ◽  
Infinite State ◽  
Concurrent Constraint Programming

The language Timed Concurrent Constraint (tccp) is the extension over time of the Concurrent Constraint Programming (cc) paradigm that allows us to specify concurrent systems where timing is critical, for example reactive systems. Systems which may have an infinite number of states can be specified in tccp. Model checking is a technique which is able to verify finite-state systems with a huge number of states in an automatic way. In the last years several studies have investigated how to extend model checking techniques to systems with an infinite number of states. In this paper we propose an approach which exploits the computation model of tccp. Constraint based computations allow us to define a methodology for applying a model checking algorithm to (a class of) infinite-state systems. We extend the classical algorithm of model checking for LTL to a specific logic defined for the verification of tccp and to the tccp Structure which we define in this work for modeling the program behavior. We define a restriction on the time in order to get a finite model and then we develop some illustrative examples. To the best of our knowledge this is the first approach that defines a model checking methodology for tccp.

scholarly journals ON SOME PROPERTIES OF TIMED FINITE STATE MACHINES

2020 ◽  
Author(s):  
Evgeniy Maximovich Vinarskii ◽  
◽  
Vladimir Anatolyevoch Zakharov ◽  
Keyword(s):  
Real Time ◽  
Computational Linguistics ◽  
Input Data ◽  
Formal Model ◽  
Reactive Systems ◽  
Real Life ◽  
Reactive System ◽  
Formal Models ◽  
Reactive Behavior ◽  
Finite State

Sequential reactive systems are formal models of programs that interact with the environment by receiving inputs and producing corresponding outputs. Such formal models are widely used in software engineering, computational linguistics, telecommunication, etc. In real life, the behavior of a reactive system depends not only on the flow of input data, but also on the time the input data arrive and the delays that occur when generating responses. To capture these aspects, a timed finite state machine (TFSM) is used as a formal model of a real-time sequential reactive system. However, in most of known previous works, this model was considered in simplified semantics: the responses in the output stream, regardless of their timestamps, follow in the same order in which the corresponding inputs are delivered to the machine. This simplification makes the model easier to analyze and manipulate, but it misses many important aspects of real-time computation. In this paper we study a refined semantics of TFSMs and show how to represent it by means of Labelled Transition Systems. This opens up a possibility to apply traditional formal methods for verifying more subtle properties of real-time reactive behavior which were previously ignored.

scholarly journals Temporal Logics Beyond Regularity

2007 ◽  
Vol 14 (13) ◽  
Author(s):  
Martin Lange
Keyword(s):  
Model Checking ◽  
Dynamic Logic ◽  
Expressive Power ◽  
Turing Machines ◽  
Temporal Logics ◽  
Propositional Dynamic Logic ◽  
Program Correctness ◽  
Recursive Procedures ◽  
Language Classes ◽  
Context Free

Non-regular program correctness properties play an important role in the specification of unbounded buffers, recursive procedures, etc. This thesis surveys results about the relative expressive power and complexity of temporal logics which are capable of defining non-regular properties. In particular, it features Propositional Dynamic Logic of Context-Free Programs, Fixpoint Logic with Chop, the Modal Iteration Calculus, and Higher-Order Fixpoint Logic.<br /> <br />Regarding expressive power we consider two classes of structures: arbitrary transition systems as well as finite words as a subclass of the former. The latter is meant to give an intuitive account of the logics' expressive powers by relating them to known language classes defined in terms of grammars or Turing Machines. <br /> <br /> Regarding the computational complexity of temporal logics beyond regularity we focus on their model checking problems since their satisfiability problems are all highly undecidable. Their model checking complexities range between polynomial time and non-elementary.

scholarly journals Composition of weighted finite transducers in MapReduce

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Bilal Elghadyry ◽  
Faissal Ouardi ◽  
Sébastien Verel
Keyword(s):  
Speech Processing ◽  
Large Scale ◽  
Large Scale Data ◽  
Finite State Transducers ◽  
Wide Range ◽  
Finite State ◽  
Common Operation ◽  
Efficient Representation ◽  
Weighted Finite State Transducers ◽  
Np Hardness

AbstractWeighted finite-state transducers have been shown to be a general and efficient representation in many applications such as text and speech processing, computational biology, and machine learning. The composition of weighted finite-state transducers constitutes a fundamental and common operation between these applications. The NP-hardness of the composition computation problem presents a challenge that leads us to devise efficient algorithms on a large scale when considering more than two transducers. This paper describes a parallel computation of weighted finite transducers composition in MapReduce framework. To the best of our knowledge, this paper is the first to tackle this task using MapReduce methods. First, we analyze the communication cost of this problem using Afrati et al. model. Then, we propose three MapReduce methods based respectively on input alphabet mapping, state mapping, and hybrid mapping. Finally, intensive experiments on a wide range of weighted finite-state transducers are conducted to compare the proposed methods and show their efficiency for large-scale data.

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