On the Expressive Power of Some Extensions of Linear Temporal Logic
One of the most simple models of computation which is suitable for representation of reactive systems behaviour is a nite state transducer which operates over an input alphabet of control signals and an output alphabet of basic actions. A behaviour of such a reactive system displays itself in the correspondence between ows of control signals and compositions of basic actions performed by the system. We believe that behaviour of this kind requires more suitable and expressive means for formal speci cations than conventional LTL. In this paper we de ne some new (as far as we
know) extension LP-LTL of Linear Temporal Logic speci cally 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 temporal logic are also languages in the alphabet of basic actions of a transducer; they represent the expected response of a transducer to the specified environmental influences. In our earlier papers we considered model checking problem for LP-LTL and LP-CTL and showed that this problem has effective solutions. The aim of this paper is to estimate the expressive power of LP-LTL by comparing it with some well known logics widely used in computer science for specification of reactive systems behaviour. We discovered that a restricted variant LP-1-LTL of our
logic is more expressive than LTL and another.
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 (HML, LTL, CTL, µ-calculus) do not suit this purpose well, since their formulae are interpreted over ω-languages, whereas the behavior of transducers are represented by binary relations on infinite sequences, i.e. by ω-transductions. To provide temporal logics with the ability to specify the property of transductions that characterize the behavior of reactive systems, we introduced new extensions of these logics. Two principal features distinguish 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 our previous papers we studied the expressive power and the model checking problem for Reg-LTL and Reg-CTL which are the extensions of LTL and CTL where the languages mentioned above are regular ones. We discovered that parametrization of this kind increases expressive power of temporal logics though retains the decidability of the model checking problem. Our next step in the systematic exploration of new extensions of temporal logics intended for specication and verication of sequential reactive systems is the study of the model checking problem for nite 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.
This book constitutes the refereed proceedings of the 4th International Conference on Tools and Methods for Program Analysis, TMPA 2017, Moscow, Russia, March 3-4, 2017. The 12 revised full papers and 5 revised short papers presented together with three abstracts of keynote talks were carefully reviewed and selected from 51 submissions. The papers deal with topics such as software test automation, static program analysis, verification, dynamic methods of program analysis, testing and analysis of parallel and distributed systems, testing and analysis of high-load and high-availability systems, analysis and verification of hardware and software systems, methods of building quality software, tools for software analysis, testing and verification.
This book constitutes the proceedings of the 35th International Conference on Application and Theory of Petri Nets and Concurrency, PETRI NETS 2014, held in Tunis, Tunisia, in June 2014. The 15 regular papers and 4 tool papers presented in this volume were carefully reviewed and selected from 48 submissions. In addition the book contains 3 invited talks in full paper length. The papers cover various topics in the field of Petri nets and related models of concurrency.
This volume constitutes the refereed proceedings of the 37th International Symposium on Mathematical Foundations of Computer Science, MFCS 2012, held in Bratislava, Slovakia, in August 2012. The 63 revised full papers presented together with 8 invited talks were carefully reviewed and selected from 162 submissions. Topics covered include algorithmic game theory, algorithmic learning theory, algorithms and data structures, automata, formal languages, bioinformatics, complexity, computational geometry, computer-assisted reasoning, concurrency theory, databases and knowledge-based systems, foundations of computing, logic in computer science, models of computation, semantics and verification of programs, and theoretical issues in artificial intelligence.
Software-dened networking (SDN) is an approach to building computer net- works that separate and abstract data planes and control planes of these systems. In a SDN a centralized controller manages a distributed set of switches. A set of open commands for packet forwarding and ow-table updating was dened in the form of a protocol known as OpenFlow. In this paper we describe an abstract formal model of SDN, introduce a tentative language for specication of SDN forwarding policies, and set up formally model-checking problems for SDNs.
Despite all the advantages brought by service-oriented architecture (SOA), experts argue that SOA introduces more complexity into information systems rather than resolving it. The problem of service integration challenges modern companies taking the risk of implementing SOA. One of important aspects of this problem relates to dynamic service composition, which has to take into account many types of information and restrictions existing in each enterprise. Moreover, all the changes in business logic should also be promptly reflected. This chapter proposes the approach to solution of the stated problem based on such concepts as model-driven architecture (MDA), ontology modelling and logical analysis. The approach consists of several steps of modelling and finite scope logical analysis for automated translation of business processes into the sequence of service invocations. Formal language of relational logic is proposed as a key element of the proposed approach which is responsible for logical analysis and service workflow generation. We present a logical theory to automatically specialize generic orchestration templates which are close to semantic specification of abstract services in OWL-S. The developed logical theory is described formally in terms of Relational Logic. Our approach is implemented and tested using MIT Alloy Analyzer software.
This paper regards problems of analysis and verification of complex modern operating systems, which should take into account variability and configurability of those systems. The main problems of current interest are related with conditional compilation as variability mechanism widely used in system software domain. It makes impossible fruitful analysis of separate pieces of code combined into system variants, because most of these pieces of code has no interface and behavior. From the other side, analysis of all separate variants is also impossible due to their enormous number. The paper provides an overview of analysis methods that are able to cope with the stated problems, distinguishing two classes of such approaches: analysis of variants sampling based on some variants coverage criteria and variation-aware analysis processing many variants simultaneously and using similarities between them to minimize resources required. For future development we choose the most scalable technics, sampling analysis based on code coverage and on coverage of feature combinations and variation-aware analysis using counterexample guided abstraction refinement approach.
A model for organizing cargo transportation between two node stations connected by a railway line which contains a certain number of intermediate stations is considered. The movement of cargo is in one direction. Such a situation may occur, for example, if one of the node stations is located in a region which produce raw material for manufacturing industry located in another region, and there is another node station. The organization of freight traﬃc is performed by means of a number of technologies. These technologies determine the rules for taking on cargo at the initial node station, the rules of interaction between neighboring stations, as well as the rule of distribution of cargo to the ﬁnal node stations. The process of cargo transportation is followed by the set rule of control. For such a model, one must determine possible modes of cargo transportation and describe their properties. This model is described by a ﬁnite-dimensional system of diﬀerential equations with nonlocal linear restrictions. The class of the solution satisfying nonlocal linear restrictions is extremely narrow. It results in the need for the “correct” extension of solutions of a system of diﬀerential equations to a class of quasi-solutions having the distinctive feature of gaps in a countable number of points. It was possible numerically using the Runge–Kutta method of the fourth order to build these quasi-solutions and determine their rate of growth. Let us note that in the technical plan the main complexity consisted in obtaining quasi-solutions satisfying the nonlocal linear restrictions. Furthermore, we investigated the dependence of quasi-solutions and, in particular, sizes of gaps (jumps) of solutions on a number of parameters of the model characterizing a rule of control, technologies for transportation of cargo and intensity of giving of cargo on a node station.
Event logs collected by modern information and technical systems usually contain enough data for automated process models discovery. A variety of algorithms was developed for process models discovery, conformance checking, log to model alignment, comparison of process models, etc., nevertheless a quick analysis of ad-hoc selected parts of a journal still have not get a full-fledged implementation. This paper describes an ROLAP-based method of multidimensional event logs storage for process mining. The result of the analysis of the journal is visualized as directed graph representing the union of all possible event sequences, ranked by their occurrence probability. Our implementation allows the analyst to discover process models for sublogs defined by ad-hoc selection of criteria and value of occurrence probability
The geographic information system (GIS) is based on the first and only Russian Imperial Census of 1897 and the First All-Union Census of the Soviet Union of 1926. The GIS features vector data (shapefiles) of allprovinces of the two states. For the 1897 census, there is information about linguistic, religious, and social estate groups. The part based on the 1926 census features nationality. Both shapefiles include information on gender, rural and urban population. The GIS allows for producing any necessary maps for individual studies of the period which require the administrative boundaries and demographic information.
Existing approaches suggest that IT strategy should be a reflection of business strategy. However, actually organisations do not often follow business strategy even if it is formally declared. In these conditions, IT strategy can be viewed not as a plan, but as an organisational shared view on the role of information systems. This approach generally reflects only a top-down perspective of IT strategy. So, it can be supplemented by a strategic behaviour pattern (i.e., more or less standard response to a changes that is formed as result of previous experience) to implement bottom-up approach. Two components that can help to establish effective reaction regarding new initiatives in IT are proposed here: model of IT-related decision making, and efficiency measurement metric to estimate maturity of business processes and appropriate IT. Usage of proposed tools is demonstrated in practical cases.