Software & Systems

Articles of journal № 4 at 2018 year.

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21. Local trends for time series pre-preparation in forecasting problems [№4 за 2018 год]
Authors: Puchkov E.V., Belyavsky G.I.
Visitors: 6405
The paper focuses on the studying local trends that describe intermediate movements in non-stationary time series. The first part of the article considers the possibilities of methods of identifying patterns in historical trends using piecewise linear approximation, piecewise logarithmic approximation and the method of local principal components. Local trends have been created using the segmentation method of the bottom-up time series, which allowed identifying the main directions of time series movement. The paper determines the quality criteria and the algorithm for identifying local trends using the proposed methods. There have been some experiments for each time series preprocessing method. It is assumed that the sequence of historical local trends describes the long-term relationship in a time series and might be successfully used for forecasting, for example, based on hybrid neural network methods. The second part of the paper considers the classical application of the Hough transformation for random points approximation on a plane by line segments. There is a disadvantage of this method comparing with the dynamic Hough transformation that takes into account the sample dynamics and can be used in online learning. The authors consider the forecasting algorithm with simultaneous calculation of a local trend using the dynamic Hough transformation. The algorithm is easily extended to other methods of data ap-proximation, which have been considered in the first part of the paper. Computational experiments included real data and used the proposed method. They provided forecasts. The experiments showed that the proposed method helps determining time series trends. The complex periodicity electrocardiogram data and closing prices of Gazprom shares were used for all experiments.

22. Computer simulation of engineering surface structure at the micro-level [№4 за 2018 год]
Authors: A.A. Rachishkin, O.V. Sutyagin, Bolotov A.N.
Visitors: 4590
This paper describes a software tool structure for computer simulation of an engineering surface topography. The model uses experimental data on the rough surface morphology. It is designed to model a 3D surface using characteristics data of contacting surface microtopography. In case of incomplete or absent data, we can use statistically processed parameters of longitudinal and transverse surface profiles. Taking into account the possible inhomogenuity of the object of research, microroughness generation uses a specially developed mathematical apparatus. The assumptions made do not affect the simulated surface credibility considerably. This approach allows designing unhomogeneous rough surfaces based on individual parameters of each surface microroughness. Analytical calculations and experimental tests showed convergence within the defined margin of error of the simulated and real surfaces. The actual rough surface inhomogeneity causes discrepancies. Full topography copying is technically feasible, but it leads to the impossibility of building computational models for studying the physical processes occurring during the contact interaction of two surfaces. Thus, making assumptions is the optimal solution when designing a computer model, which is the basic module of the program for studying the process of rough surface interaction with the possibility of applying functional coating. The developed mathematical apparatus and the accepted input parameters make it possible to simulate a real rough surface with the highest possible reliability. It can be a simulation of existing rough surfaces with known processing parameters, or preliminary design of the most optimal surface topography that is necessary to solve a specific engineering task. This software combines modern information technologies and analytical developments of rough surface generation. It is a separate basic module of the friction unit modeling system.

23. A software model for studying the effectiveness of procedures for extracting contours of noisy images [№4 за 2018 год]
Authors: Samoylin E.A., S.A. Karpov
Visitors: 7968
The article develops one of the directions of digital image processing – extracting their contours. It is necessary to solve this task in order to recognize objects in the image (by geometry, the angles between contour fragments, etc.), to improve image visual quality, to emphasize the boundaries of objects of interest, contrasting, etc. Typically, digital images are recorded in difficult and adverse conditions, which leads to noise generation described by an additive Gaussian noise model. Therefore, the authors propose a software model that allows investigating the effectiveness of various methods, algorithms and procedures to extract noisy image contours. The model is based on comparing an image contour from a noisy image to an ideal contour of a similar image without noise. Then it is supposed to calculate the errors of detection of contour elements of the first (false alarm) and the second (pass) kind. In this case, the error calculation is carried out over the entire possible range of the mean square deviation σ of additive Gaussian noise. The paper gives some examples of extrating contours of real scene noisy images, as well as dependences of error frequencies of the first and second kinds on the mean square deviation of the amplitude noise from σ=0 to σ=200 (images at 256 levels of brightness amplitude quantization) for three procedures for contour extraction: based on Prewitt masks, Sobel mascs and the Laplacian of Gaussian. In addition, the authors study the influence of a noisy image linear filtering procedure on the decrease in the frequency of errors in the extrating contours of the first and second kinds.

24. Evaluating the quality of heterogeneous robotic systems using the Banker-Charnes-Cooper model [№4 за 2018 год]
Authors: D.E. Seliverstov, K.D. Rusakov , S.Sh. Hill , S.B. Savilkin
Visitors: 5601
The paper proposes a method for evaluating and determining the ways for improving the quality of heterogeneous robotic systems that consists of private methods. It is based on the developed complex of mathematical models that is based on the methodology of the data envelopment analysis. One of the features of the data envelopment analysis by evaluating complex system effectiveness is the fact that the object under study has a variety of input and output heterogeneous parameters. In this case, the solution of the problem is carried out under conditions of heterogeneity of the parameters, which is of particular importance in the case of system heterogeneity. After complex mathematical transformations, modeling based on the data envelopment analysis makes it possible to “compare something noncomparable”. The method for evaluating the quality of heterogeneous robotic systems supposes a certain number of factors described in the paper. It is based on the developed mathematical models for evaluating the quality of heterogeneous robotic systems and theoretical provisions on the quality criteria the object under study. The paper shows that if the constraints make it necessary to achieve the maximum level of the output indices at fixed values of the entry indicators, then we should choose the developed model for the analysis of heterogeneous robotic systems based on the Banker-Charnes-Cooper output model of the data envelopment analysis. This mathematical model allows analyzing the quality of heterogeneous robotic systems in conditions of possible cost reduction with fixed values of output characteristics. If the determination of the ways of improving the quality of heterogeneous robotic systems is carried out under conditions of possible simultaneous changing of the values of both input and output parameters, then we choose a synthesis model based on the additive model of methodology of the data envelopment analysis.

25. Information system for selecting control channels for a process facility to synthesize an energy-saving control system [№4 за 2018 год]
Authors: A.V. Sobolev, А.I. Lyashenko, D.P. Vent
Visitors: 4969
Modern automatic control systems are able to solve a variety of tasks in various industries. In this case, the success of the system implementation depends on the purpose of its construction formed as a certain optimality criterion. The paper analyzes the current state of the problems of energy-saving management of chemical-technological systems. It is noted that energy efficiency improvement is complicated while ensuring the operational speed of chemical-engineering system management. It is proposed to solve this problem by creating energy-saving automatic control systems with an excessive number of control actions which are different in frequency and energy characteristics. The paper proposes an information system structure to analyze a multidimensional control object in order to identify dynamic and energy efficient control channels and the subsequent synthesis of an energy-saving automatic control system. The authors describe the main modules of the information system, synthesis and analysis problems solved in them, the structure of the constituent subsystem interaction. An algorithm for selecting an energy-efficient control channel is based on exergy sensitivity. The exergy characteristics of technological processes give an objective evvaluation of the use of dissimilar energy resources and identify energy saving reserves. The paper presents a logical structure of the subsystem of exegetics analysis of chemical-technological systems, a class diagram, their basic functions and methods. There are also recommendations for the use of an automated system for exergy analysis of a chemical-technological system. The proposed algorithm for choosing a dynamically efficient control channel is based on an iterative procedure of calculating a quadratic integral criterion for a given frequency operating range.

26. Comparative analysis of spinlock realizations [№4 за 2018 год]
Authors: D.S. Tarakanov, Kosyakov M.S.
Visitors: 4867
The paper considers the problem of performance of multithreaded applications using spinlocks to synchronize access to a critical section. There is a detailed description of this mechanism, indicating potential bottlenecks. There is also an analysis of the existing spinlock implementations (such as POSIX spinlock, ticket spinlock and MCS spinlock) with a de-tailed explanation of their internal structure. In order to evaluate the effectiveness, the authors introduce two characteristics as follows: application agility (time in processor cycles) and the fulfillment of a fairness condition (quantified). The described spinlocks have been prepared and optimized to compare these implementations of spinlocks using a multi-core processor with shared last level cache. In addition, a test application is developed that allows varying the number of threads and the payload in the critical section and outside. The paper contains diagrams and graphs for the values of the introduced charachteristics. Based on the data obtained, characteristic problems (insufficient scalability, non-fulfillment of the fairness condition) for POSIX-spinlock and ticket spinlock are revealed, which negatively affect the performance of applications using these synchronization primitives. An analysis of the causes of these problems shows that the use of POSIX-spinlock and ticket spinlock leads to the need for permanent cache synchronization. Additionally, it is shown that POSIX-spinlock is not fair, and MCS-spinlock might potentially be inefficient with a small number of threads. The obtained results might be used both for further research of synchronization primitives associated with other implementations of the MCS-mechanism or non-blocking algorithms and be considered when choosing a spinlock to use in a real application.

27. A translator of a tactical task to a Petri net for a group of unmanned ground vehicles [№4 за 2018 год]
Authors: A.A. Tachkov, A.V. Kozov, S.E. Pankov
Visitors: 7151
This paper represents analytics of main existing approaches to forming a tactical task for a group of unmanned military robotic vehicles. The selected approach uses an electronic map as a graphic basis to form a task using military symbols. The paper shows that operator's decision might be represented as an oriented multigraph with finite numbers of vertices and arcs. Within this representation, the developed task translator allows converting an initial operator’s decision (defined with military symbols) into an equivalent Petri net to control a group of military robotic vehicles. The paper defines target formalities for translator design, structure, basic blocks and standard translation rules. The developed translator uses a geoinformation system and a military symbol classifier for coding group actions of robotic systems. The software for the translator is in C++ as a DLL library for Panorama geoinformational system. There is also a class diagram. The paper presents an example to show how the translator works. There is a typical task for a group of robotic vehicles. It includes division into sub-groups, parallel moving onto firing line, reallocation of complexes among subgroups, reaching the objective. The initial operator's decision is represented by military symbols. The paper also shows an equivalent Petri net. The proposed translator with an electronic map technology allows automating tactical task formation for a group of robotic military unmanned vehicles.

28. Grammar for queries for heterogeneous data storage in proactive systems [№4 за 2018 год]
Authors: Tran Van Phu, Sai Van Cuong , M.V. Shcherbakov
Visitors: 6920
The problem of storage and processing of heterogeneous data (both structured and non-structured) from various data sources is an important issue when implementing proactive support systems for a life cycle operation stage of complex multi-object distributed systems. The data are heterogenous, so it is required to store data descriptions (metadata) for subsequent automatic processing. In order to solve the problem of heterogeneous data efficient storage, an architecture called data lake is used. It implements mechanisms for data batch processing and real-time data processing. The task of improving methods for effective access to heterogeneous data includes the following subtasks: development of SQL query grammar for heterogeneous data; building a parser for recognizing queries according to new grammar; development of modules for processing heterogeneous data according to a query; development of recommendations (methods) for applying the developed modules in proactive decision support systems. The proposed grammar is based on the DML extension of the SQL language, in particular the SELECT statement extension. There is the generated parser using the ANTLR 3.0 library for processing the generated queries according to new grammar. Due to generation, there are some created classes in JAVA with their objects used for parsing queries. The generated parser and processing modules for heterogeneous data have become a basis for the new software. After testing the software that implements the proposed grammar in the proactive decision support system, the authors have analyzed the time of execution of unified queries with different volumes of heterogeneous data. The main result of the grammar application is the reduction in the heterogeneous data processing time within a single query.

29. Application development for preparing meshes using snappyHexMesh of OpenFOAM [№4 за 2018 год]
Authors: Chitalov, D.I., S.T. Kalashnikov
Visitors: 8661
The paper describes an application with a graphical user interface for preparing computational meshes that contain hexahedra and split-hexahedra from triangulated surface geometries using the OpenFOAM software environment, and the application development process. The paper presents the existing paid and open software tools used to simplify the problem of preparing such computational meshes. The authors determine their limitations and relevance of the indicated problem and the necessity of developing a new application for preparing meshes for OpenFOAM SE. The authors have made a list of tasks to implement the development. They have studied the operating principle of OpenFOAM SE utility responsible for the mentioned type of CM generation. The determined list of necessary tools for program development includes a programming language of application logic, a library that provides implementation of interface elements, and the development environment. The authors indicate the software required to use the developed application. There are diagrams that describe the application structure, the algorithm of user's work with application. The paper also determines some difficulties in algorithm implementation and program logic and proposes the ways to solve them. The application has been tested on the training task included in of OpenFOAM SE. The authors summarize the results of the conducted research, evaluate the practical importance of the conducted research work and the created software application, possible prospects of the research. The paper provides a web resource that contains the developed application, which is freely available, for testing and practical using.

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