«Systems and Means of Informatics»
Scientific journal
Volume 31, Issue 3, 2021
Content | About Authors
Abstract and Keywords.
- T. A. Milovanova
- I. S. Zaryadov
- L. A. Meykhanadzhyan
Abstract: Multiserver queuing system with a finite number of identical servers and one queue of unlimited capacity is being considered. Customers enter the system one by one in accordance with a recurrent flow. Service times are exponentially distributed with the same parameter. General renovation mechanism is implemented in the system: a customer, whose service has been completed, upon leaving the system removes a random number of other customers from the queue according to a given probability distribution. The method is proposed for finding the joint stationary distribution of the total number of customers in the system and the time elapsed since the last arrival. Expressions (in terms of transforms) for the calculation of the transient joint distribution are presented.
Keywords: queueing system; general renovation; queue management
- M. O. Vorontsov
- A. A. Kudryavtsev
- O. V. Shestakov
Abstract: Currently, much attention of researchers is paid to generalizations of well-known mathematical objects in order to obtain adequate models describing real phenomena. An important role in the applied theory of probability and mathematical statistics is played by the gamma class of distributions, which has proven to be a convenient and effective tool for modeling a lot of real processes.
The gamma class is quite wide and includes distributions that have such useful properties as, for example, infinite divisibility and stability, which makes it possible to use distributions from this class as asymptotic approximations in various limit theorems. One of the most important tasks of applied statistics is to obtain estimates of the parameters of the model distribution from the available real data. The paper considers the gamma-exponential distribution which is a generalization of the distributions from the gamma class. Estimates and asymptotic confidence intervals are given for some parameters of this distribution.
The problems of computer modeling of sample realizations from the gamma- exponential distribution and the numerical estimation of parameters for the sample are discussed. The results of the work can be widely used in the study of probabilistic models based on continuous distributions with an unbounded nonnegative support.
Keywords: computer modeling; parameter estimation; gamma-exponential distribution; mixed distributions; generalized gamma distribution
- P. V. Shnurkov
- K. A. Adamova
Abstract: The paper proposes and analyzes anew stochastic model of regeneration of continuous product stock control. The volume of stock at an arbitrary moment of time is the status of the system. The control parameters are a maximum deterministic allowable stock volume and a random time from replenishment until control - medium specific profit, an explicit analytical representation was obtained. By its structure, this indicator is a fractional linear integral functional from the distribution of a random control parameter. The integrands in the numerator and the denominator of the specified functional depend on the second deterministic control parameter. A special form of the theorem on the extremum of a fractional linear integral functional is used to solve the optimization problem. An analytical study of the main function of this functional on the global extremum was conducted. Based on this study, analytical properties of the original characteristics of the model, under which there is an optimal solution of the management task, are established and a description of this solution is obtained.
Keywords: continuous product stock control; controlled regenerating process; linear-fractional integral functional
- I. N. Rozenberg
- S. K. Dulin
- N. G. Dulina
Abstract: The paper analyzes the processes typical for the digitization of information, and the standardization of digitization in the information environment.
Three stages of information digitization and their features are considered. It is noted that the most important condition for digital transformation is to ensure the level of semantic interoperability. The characteristic features of this level are described.
Keywords: digitization; digitalization; digital transformation; interoperability; semantic geointeroperability
- A. A. Grusho
- A. A. Zatsarinny
- E. E. Timonina
Abstract: The paper deals with an electronic ledger based on the concept of blockchain. The development of the traditional blockchain is the tangle (tangle), which is represented by an oriented acyclic graph (DAG - Directed Acyclic Graph) and which securely stores transaction information. A centralized consensus implies a concentration of control functions in a single body. The scaling up of e-books in some cases poses threats of corruption and fraud. Three types of threats are considered that are determined by corruption and collusion of legal entities. Ensuring information security when scaling electronic books is a direction that begins to develop in connection with the growth of the digital economy.
Keywords: information security; tangle; blockchain; threats of corruption and fraud
Abstract: An effective solution to problems of multivariate data analysis requires the use of complex probabilistic models, among which the probabilistic model of principal component analysis (PPCA) occupies a worthy place. It allows one to adequately describe real data, formally formulate and solve the problem of choosing its parameters. Practical application of PPCA is associated with a large number of laborious computations. The article discusses techniques for significantly reducing the time spent in calculating the density of the multivariate normal distribution. For this, the expediency of using the Cholesky expansion for the covariance matrix and Woodbury identity for its PPCA factorization is substantiated. A brief description of the experiments is given, which makes it possible to evaluate the real time characteristics of the algorithms and to reveal the conditions for their effective application. Along the way, recommendations are given on the implementation of individual operations.
Keywords: PPCA computing; Cholesky factorization; Woodbury matrix identity; computing experience
- N. I. Sidnyaev
- Yu. I. Butenko
- E. E. Sineva
Abstract: The paper reveals the basic principles of building expert systems in the aviation industry. A model of knowledge representation that provides information and structural reliability of the expert system's knowledge base for describing aircraft structures has been developed. The article analyzes the paradigmatic features of aerospace terminology in order to improve the efficiency of information search. A method for resolving lexical ambiguity of a search query in the knowledge base is proposed. Inference engine and explanation mechanism of the knowledge base premised on the Charles Fillmore's case grammar is described. The grammatical cases make it possible to determine the semantic and syntactic structure of the output sentence. Restrictions show the number of participants in the situation that a verb can attach, it is possible to provide effective output of information from the knowledge base.
Keywords: expert system; knowledge base; aircraft; terminology; knowledge
- A. V. Bosov
- A. A. Kryukov
Abstract: A methodology for assessing production risks at the stage of research and development work (R&D) in the development of high-tech products is presented. To take into account the complex classification of production risks, various sources of their occurrence, and spheres of influence on the R&D result, it is proposed to introduce a combined methodological approach and assess production risks partly by statistical methods and partly by the method of expert assessments. The content of the stages of the corresponding methodology is considered. The method of calculating the integral assessment of production risk and the scale of the levels of production risks of the project in accordance with the nature of the impact and acceptability are substantiated.
Keywords: methodology for assessing industrial risks; experimental and design works; method of expert assessments; statistical methods
Abstract: The paper provides an overview of the concept, main structural constituents, and functions of supracorpora databases (SCDB). Supracorpora databases represent a novel type of structured information resources that significantly expand capabilities of linguistic text corpora, parallel corpora in particular. The paper outlines principle features and limitations of parallel corpora and demonstrates how SCDBs allow extending these features and overcoming the limitations. Supracorpora databases allow linguistic experts to establish, record, and annotate translation correspondences between language units in the source and target texts while relying on faceted classification categories composed by the researchers themselves according to their requirements. The article also describes the general structure of SCDB architecture developed in FRC CSC RAS which incorporates corpus and subcorpus constituents that interact with one another as a part of a common database.
Keywords: corpus linguistics; supracorpora database; parallel corpus; linguistic annotation; information technologies; faceted classification
- Yu. A. Stepchenkov
- N. V. Morozov
- Yu. G. Diachenko
- D. V. Khilko
Abstract: The paper presents the results of hybrid architecture of recurrent multicore signal processor (HARMSP) hardware implementation as register transfer level VHDL-model and its prototype approbation on a development board with Intel Arria10 field-programmable gate array (FPGA). HARMSP consists of von-Neumann master processor at control architecture level and data-flow recurrent processor with four computing sections at operational level. Hardware HARMSP model is a complex of software or hardware control processor (CP) implementation and operational level VHDL-model. CAD Quartus (Intel) provides the software CP implementation on FPGA, whereas SoC FPGA on the development board contains the hardware CP implementation as dual-core Cortex-A9 processor.
Keywords: recurrent signal processor; multicore hybrid architecture; VHDL- model; FPGA
- I. A. Kochetkova
- A. I. Kushchazli
- P. A. Kharin
- S. Ya. Shorgin
Abstract: For 5G, the coexistence of two scenarios within the same network - ultrareliable low-latency communication (URLLC) and enhanced mobile broadband (eMBB) - is an actual task. For a scheme with the occupation of not the whole, but a part of the resource block, a model of coexistence of narrow-band URLLC traffic and broadband eMBB traffic in the form of a queuing system with priority access - reducing and interrupting the service of broadband traffic when narrow-band traffic arrives - is proposed. The authors formulate the problem of maximizing the average speed of broadband traffic transmission by the values of speed levels and with restrictions on the probability of blocking and the probability of interrupting broadband traffic service. The results of a numerical analysis of priority access efficiency indicators, such as the average number of eMBB sessions and probability of service interruption, are presented.
Keywords: 5G; eMBB; URLLC; queuing system; priority admission control; interruption; bit rate degradation
- E. V. Bobrikova
- A. A. Platonova
- Yu. V. Gaidamaka
- S. Ya. Shorgin
Abstract: The article proposes a method for assigning a modulation-code scheme by a base station scheduler based on predicting the value of the signal-to- interference ratio on the mobile user's equipment at the next time slot from a sequence of known values of this ratio in the past. For prediction, a model of a single-layer neural network is built in the work, by the example of which a machine learning process is shown for solving a multiparametric optimization problem using the stochastic gradient method. The trained neural network for the predicted value of the signal/interference ratio allows the scheduler to correctly select the modulation-code scheme for the user, thereby ensuring the level of quality of data transmission in the radio channel required for the provision of the service.
Keywords: SINR; machine learning; neural network
- A. Yu. Egorova
- I. M. Zatsman
- V. A. Nuriev
Abstract: The paper considers the error classification applied in the expert evaluation of the machine translation quality. The classification includes common error headings (for errors at the level of grammar, vocabulary, punctuation, etc.) as well as headings that are associated with a specific type of linguistic unit selected for evaluating the machine translation quality. The quality evaluation is performed by experts as they linguistically annotate machine translation outcomes. If, while annotating, an expert finds errors, then headings, necessary to characterize these errors, are included in the annotation. The headings allow one to calculate the relative frequency of machine translation errors for the array of test sentences selected for translation and quality evaluation. The main goal of the paper is to describe the proposed classification of common and specific errors. The principal difference of the classification from the existing error classifications is that it is aimed at backing interval evaluation for machine translation systems, whose quality of work may vary over time. The headings of the proposed classification allow experts to record both improvements and decreases in machine translation quality at a given time interval.
Keywords: machine translation; quality evaluation; error classification; common errors; specific errors; linguistic annotation; interval evaluation
- I. M. Adamovich
- O. I. Volkov
Abstract: The article is devoted to the further development of the distributed technology of concrete historical investigation support, based on the principles of crowdsourcing and focused on a wide range of users which are nonprofessional historians and biographers. Development is carried out through integration with geographic information systems (GIS), the use of which in historical research is the trend in recent years. The analysis of the problems of GIS integrating into the technology under consideration and the description of the ways to solve them have been made. The article analyzes the tasks and features of GIS in historical research and evaluates the possibility and prospects of using the mechanism of geochronological tracking. Possible problems of including the GIS elements in the technology, which are the consequence of the specificity of concrete historical investigation, are analyzed. The methods for solving the identified problems are proposed. The necessary modification of the object model of the technology in the form of the introduction of a new type of data for the connection of the elements of the semantic network of technology with cartographic information is described.
Keywords: concrete historical investigation; distributed technology; GIS; data model; geochronological tracking
Abstract: An updated methodology for symbolic modeling of programmable tasks is presented, designed to build knowledge systems about tasks that are intended for automated design of programs. Task constructions are created by means of memory links between tasks, represented by task constructive objects.
Three types of memory link functions are defined, each of which allows assigning to a pair of tasks some third task formed from this pair. The task graph serves as representation of the problem area, designed to formalize task knowledge and implement the process of constructing tasks. The required construction is described by the problem specification, which contains a description of its memory, restrictions on the number of task vertices (and, if necessary, restrictions related to the accuracy of result, etc.). The mechanism of searching the resolving structures matches the specification of the original problem with a subgraph on the task graph by implementing three types of behavior in accordance with three types of requests for constructing.
Keywords: symbolic modeling of tasks; task constructive object; system of knowledge about tasks; task graph; resolving structure; constructing programs
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