Volume 19, Nº 5 (2020)
Artificial intelligence, knowledge and data engineering
Context-Aware Approach to Intelligent Decision Support Based on User Digital Traces
Resumo
A context-aware approach to intelligent decision support based on user digital traces is proposed. The concept of human digital life with regard to intelligent decision support is discussed. The aims of addressing this concept in diverse domains are clarified and approaches to modelling human digital life are identified. In the proposed approach, digital traces serve as a source of information to reveal user preferences and decision-making behaviour. Perspectives on decision support based on user digital traces are developed. The research outcomes are the specification of requirements to intelligent decision support based on user digital traces, the principles, conceptual framework and information model of such support. The principles form the basis for the conceptual framework of intelligent decision support based on user digital traces. Components of the conceptual model are user profiles; a user digital life model that structures information containing in the digital traces; group patterns that describe preferences and decision-making behavior shared by a user group; and a decision maker ontology. The information model defines information flows between the framework’s components, identifies tasks that require solutions to implement the framework and offers techniques for this. The novelties of the research are applying the concept of human digital life to intelligent decision support and context-dependent ontological inference of the type of user as a decision-maker, which determines a group of users sharing their preferences and behaviours with the active user, to predict a recommended decision. The paper contributes to the areas of modelling human digital life and intelligent decision support.
Informatics and Automation. 2020;19(5):915-941
915-941
Robotics, automation and control systems
Stability Analysis of Swarm Heterogeneous Robots with Limited Field of View
Resumo
This paper presents a stability analysis of swarm robots, a group of multiple robots. In particular, we focus on robot swarms with heterogeneous abilities, in which each robot has a different sensing range and physical limitations, including maximum velocity and acceleration. In addition, each robot has a unique sensing region with a limited angle field of view. We previously proposed a decentralized navigation method for such heterogeneous swarm robots consisting of one leader and multiple followers. With the decentralized navigation method, a single leader can navigate for followers while maintaining connectivity and satisfying the physical limitations unique to each robot; i.e., each follower has a target robot and follows it without violating its physical limitations. In this paper, we focus on a stability analysis of such swarm robots. When the leader moves at a constant velocity, we mathematically prove that the shape and orientations of all robots eventually converge to the equilibrium state. For this, we must first prove that the equilibrium state exists. Then, we show the convergence of the state to its equilibrium. Finally, we carry out experiments and numerical simulations to confirm the stability analysis, i.e., the convergence of the swarm robots to the equilibrium states.
Informatics and Automation. 2020;19(5):942-966
942-966
Digital information telecommunication technologies
Model of Satellite Communication Channel Functioning under Conditions of Disturbances of Service Part of Frames by Unsteady Interference
Resumo
The paper describes the main ways of organizing modern satellite communication systems and the methods of synchronization and transmission of service information used in them, the frame synchronization mechanism from the view point of noise immunity. Based on the analysis, a block diagram of a simulation model is proposed for studying the influence of unintentional interference on the channels of modern satellite communication systems. The proposed model of the impact of non-stationary interference on a satellite communication channel takes into account the effect of interference on symbolic, frame synchronization, mechanisms for extracting frame boundaries, as well as the effect of modern error correction codes. The model allows evaluating the impact of non-stationary interference on both the information and the service side of the frame of modern systems of broadband satellite communications. As an indicator of the noise immunity of a satellite communication channel, there was used probability of frame loss, i.e. frame skipping due to a violation in the frame synchronization system, incorrect allocation of frame boundaries, or the presence of errors in the frame that were not repaired by corrective codes. Using this model, we studied the effect of non-stationary interference of various durations on the information and service parts of the frame, compared the results of the impact of non-stationary interferences of various durations with the effect of white Gaussian noise. It is shown that non-stationary interference, which are short noise pulses that do not affect the information part of the frame due to reparation by correction codes, can significantly reduce the reception quality due to disruption of frame synchronization and distortion of service information about the signal-code structure and frame length.
Informatics and Automation. 2020;19(5):967-990
967-990
Unified Speech-Like Interference for Active Protection of Speech Information
Resumo
The paper considers the possibility of creating a speech-like interference for the means of vibro-acoustic protection of speech information based on tables of syllables and words of the Russian language. The choice of research directions and experimental conditions is substantiated: synthesis of sound files by random sampling of speech elements from a database, research of spectra of synthesized noise, algorithm for creating interference of the “speech choir” type, study of autocorrelation functions of synthesized speech-like interference, as well as their probability distribution density. It is shown that the spectral and statistical characteristics of the synthesized speech-like interference type "speech choir" of five voices are close to similar characteristics of real speech signals. At the same time, the speech choir was formed by averaging the instantaneous values of temporary realizations of sound files. It is shown that the spectral power density of the speech-like interference of the “speech choir” type practically is not changed with the number of averaged “voices” starting from five. The probability density distribution of the speech-like interference value with an increase in the number of voices in the “speech choir” approaches the normal law (unlike a real speech signal whose probability density is close to the Laplace distribution). Evaluation of the autocorrelation function gave a correlation interval of several milliseconds. The articulation tests of speech intelligibility using synthesized speech-like interference with different signal-to-noise ratios showed the possibility of reducing the integral noise level by 12-15 dB compared to noise-like interference. The dependencies of verbal intelligibility on the integral signal-to-noise ratio are constructed on the basis of polynomial and piecewise linear approximations. A preliminary assessment of a possible impact of speech-like interference on the psycho-emotional state of a person was performed. The direction of further research on increasing the efficiency of algorithms for generating speech-like interference is discussed.
Informatics and Automation. 2020;19(5):991-1017
991-1017
Algorithm and Technical Solutions for Dynamic Configuration of Client-Server Computing Networks
Resumo
The main factors that determine the expansion of capabilities and increase the effectiveness of network intelligence to identify the composition and structure of client-server computer networks due to the stationarity of their structural and functional characteristics are analyzed. The substantiation of an urgent problem of dynamic management of structurally-functional characteristics of the client-server computer networks functioning in the conditions of network reconnaissance is resulted on the grounds of the revealed protection features of client-server computer networks at the present stage that is based on realization of principles of spatial safety maintenance, and also formalization and introduction of forbidding regulations.
The mathematical model allowing to find optimum modes for dynamic configuration of structurally-functional characteristics of client-server computer networks for various situations is presented. Calculation results are given. An algorithm is presented that makes it possible to solve the problem of dynamic configuration of the structural and functional characteristics of a client-server computer network, which reduces the reliability time of data obtained by network intelligence. The results of practical tests of software developed on the basis of the dynamic configuration algorithm of client-server computer networks are shown. The obtained results show that the use of the presented solution for the dynamic configuration of client-server computer networks allows to increase the effectiveness of protection by changing the structural and functional characteristics of client-server computer networks within several subnets without breaking critical connections through time intervals that are adaptively changed depending on the functioning conditions and the attacker’s actions.
The novelty of the developed model lies in the application of the mathematical apparatus of the Markov’s theory of random processes and Kolmogorov’s solution of equations to justify the choice of dynamic configuration modes for the structural and functional characteristics of client-server computer networks. The novelty of the developed algorithm is the use of a dynamic configuration model for the structural and functional characteristics of client-server computer networks for the dynamic control of the structural and functional characteristics of a client-server computer network in network intelligence.
Informatics and Automation. 2020;19(5):1018-1049
1018-1049
Information security
Problematic Issues of Information Security of Cyber-Physical Systems
Resumo
This paper is an analysis and systematization of modern research in the field of cyber-physical system information security. The problematic issues of information security of such systems are considered: «what is being attacked?», «who is attacking?», «why is someone attacking?», «how is someone attacking?» and «how to protect the system?». As an answer to the first question, the paper proposes a definition and classification of cyber-physical systems according to such criteria as complexity, connectivity, criticality and social aspect. As an answer to the second and the third questions, the paper describes a classification of attacker according to such criteria as type of access, method of access, intentions, knowledge and resources. As an answer to the fourth question, the paper contains a classification of attack actions according to such criteria as subject and object, method of influence, prerequisites and consequences. As an answer to the fifth question, the paper proposes a classification of protection methods and security tools according to such criteria as principle of operation, object of protection and task to be solved. The scientific significance of the paper is systematization of a current state of the art in the subject area. The practical value of the paper is providing information about security issues that are specific to cyber-physical systems, which will allow one to develop, manage and use such systems in a more secure way.
Informatics and Automation. 2020;19(5):1050-1088
1050-1088
Analysis of Modern Methods to Ensure Data Integrity in Cyber-Physical System Management Protocols
Resumo
At present, the problem of creating methodological security of cyberphysical systems, in particular, the design and implementation of information security subsystems is acute. At the same time, the landscape of threats and vulnerabilities typical for a wide range of hardware and software technologies used in cyberphysical systems is extremely wide and complex. In this context, the security of application layer protocols is of paramount importance, as these protocols are the basis for interaction between applications and services running on different devices, as well as in cloud infrastructures. With the constant interaction of the systems under study with the real physical infrastructure, the challenge is to determine effective measures to ensure the integrity of the transferred control commands, as disruption of the performed critical processes can affect human life and health. The paper provides an analytical review of the main methods of data integrity assurance in management protocol of cyberphysical systems, as well as an overview of application layer protocols vulnerabilities widely used in cyberphysical systems of different types. Classical methods of data integrity assurance, new methods, in particular, blockchain, as well as the main directions of increasing the efficiency of data integrity protocols in cyberphysical systems are considered. Analysis of application layer vulnerabilities is carried out on the example of the most popular MQTT, CoAP, AMQP, DDS, XMPP specifications and their implementations. It is established that despite the presence of basic security mechanisms in all these protocols, researchers continue to regularly identify vulnerabilities in popular implementations, that often endangers critical infrastructure services. In the course of preparing the review of the existing methods of data integrity assurance for the examined class of systems, the key problems of these methods integration and ways of their solution were defined.
Informatics and Automation. 2020;19(5):1089-1122
1089-1122