The article considers an example of an adaptive protection system focused on protection from heterogeneous misinforming impacts to computer networks. The system adaptation to the current conditions is being performed by means of its reconfiguring. Reconfiguring implies adjusting particular blocks of the system to the current situation, as well as selecting appropriate methods of revealing false information in heterogeneous data. Reconfiguring is based on the automata objects model. As an example, data exchange TLS protocol is considered.

Architecture of the Software System for Adaptive Protection of Network Infrastructure

Grammatical inference of context-free grammars using positive and negative language examples is among the most challenging task in modern artificial and natural language technology. Recently, several implementations combining various techniques, usually including the Backus–Naur form, have been proposed. In this paper, we explore a new implementation of grammatical inference using evolution methods focused on the Greibach normal form and exploiting its properties, and also propose new solutions both in the evolutionary processes and in the corresponding fitness estimation.

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Building Greibach Normal Form Grammars Using Genetic Algorithms

Event-driven software systems, belonging to the class of systems with complex behavior in the scientific literature, are reactive systems, which react to the same input effect in different ways depending on their state and background.
It is convenient to describe such systems using state-transition models utilizing special language tools, both graphical and textual. Methodology for automated development of systems with complex behavior using the designed CIAO language (Cooperative Interaction of Automata Objects), which allows formally specifying the required behavior based on an informal description of the reacting system, is presented.
An informal description of a reacting system can be provided verbally in a natural language or in another way adopted in a specific domain. Further, according to this specification in the CIAO language, a software system for interacting automata in the C++ programming language is generated with a special system.
The generated program implements a behavior guaranteed to correspond to a given specification and original informal description. CIAO provides both graphical and textual notation. Graphic notation is based on an extended notation of state machine diagrams and component diagrams of the unified modeling language UML, which are well established in describing the behavior of event-driven systems.
The text syntax of the CIAO language is described by context-free grammar in regular form. Automatically generated C++ code allows using of both library and any external functions written manually.
At the same time, the evident correspondence of the formal specification and the generated code is preserved on conditions that the external functions conform to their specifications.
As an example, an original solution to D. Knut's problem of a responsive elevator control system is proposed. The effectiveness of the proposed methodology is demonstrated, since the automaton-converter generating the C++ code is presented as a responsive system, is specified in the CIAO language and implemented by the bootstrapping. The proposed methodology is compared with other well-known formal methods for describing systems with complex behavior.

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Методика построения событийно-управляемых программных систем с использованием языка спецификации CIAO

Supercombinator set acquired from context-free grammar samples

Regularization of translational context-free grammar via equivalent transformations is a mandatory step in developing a reliable processor of a formal language defined by this grammar. In the 1970-ies, the multi-component oriented graphs with basic equivalent transformations were proposed to represent a formal grammar of ALGOL-68 in a compiler for IBM/360 compatibles. This paper describes a method of grammar regularization with the help of an algorithm of eliminating the left/right-hand side recursion of nonterminals which ultimately converts a context-free grammar into a regular one. The algorithm is based on special equivalent transformations of the grammar syntactic graph: elimination of recursions and insertion of iterations. When implemented in the system SynGT, it has demonstrated over 25% reduction of the memory size required to store the respective intermediate control tables, compared to the algorithm used in Flex/Bison parsers.

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Ludmila Fedorchenko

Papers

Equivalent Transformations and Regularization in Context-Free Grammars