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№2
Publication date:
16 June 2019
Latest issue articles
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1. Problem solving experience in data visualization using ArcGIS software [№1 за год]
Author: Youssef Al-Damlakhi
Visitors: 199
Most users of geographic information systems (GIS) software, in particular, ArcGIS, which is considered one of the most com-mon GIS programs for implementing various applications and visualizing 3D data, do not pay much attention to input data com-patibility. This is also the case of the coordinate systems and projections that are the basis of working in GIS. Therefore, some-times specialists who work with GIS programs without experience or knowledge in cartography have problems. Thus, the ability of GIS users to have basic knowledge of GIS related sciences such as cartography and geodesy is important. The paper introduces some of the ArcScene program capabilities for visualizing and displaying 3D data. In addition, it dis-cusses most frequent difficulties in this field. For example, when displaying 3D data in ArcScene program or when displaying the slopes of the earth's surface based on the data of the DEM (Digital Elevation Model) layer. The paper also describes in detail the reasons and ways to resolve such difficulties.
2. The model of fault-tolerant cluster reliability with virtual machine migration [№1 за год]
Authors: S.M. Aleksankov , V.A. Bogatyrev, A.N. Derkach
Visitors: 207
Ensuring high reliability, fault tolerance and computing process continuity of computer systems is supported by clustering computing re-sources. It is based on the virtualization technology as a result of moving virtual resources, services, or applications between physical servers with the support of computing process continuity. The object of study is a fault-tolerant cluster, which in the simplest case consists of two physical servers (primary and backup) connected through a switch. Each server has a local hard disk. Server local disks have a distributed storage system with data synchronous replication from the source server to the backup server. The virtual machine is running on the cluster. The system involves running a shadow copy of the virtual machine on a backup server, which allows computational process implementation without interruption after the primary server fails to continue its implementation on the virtual machine backup server. Stationary and nonstationary availability coefficients are used as a reliabil-ity indicator. The paper proposes the Markov reliability model of a fault-tolerant cluster, which takes into account virtual machine migration costs, as well as mechanisms ensuring the continuity of the computing process (service) in the cluster in case of one physical server failure. After mi-gration, two copies of virtual machines located in different physical servers are supported in memory, so that in case of failure of one of them to continue working on the second one. There is a developed simplified model of a fault-tolerant cluster that ignores the costs of virtual machine migration when restoring a clus-ter. It gives an upper reliability evaluation. The paper shows the notable impact of the virtual machine migration process on the failover clus-ter reliability (measured by a non-stationary availability coefficient). The obtained results can be used to justify the choice of fault tolerance and continuity of the computing process of computer systems of cluster architecture.
3. Comparison the efficiency of adaptive algorithms of traffic control in AnyLogic [№1 за год]
Author: S.A. Andronov
Visitors: 201
The paper considers the issues of traffic flow simulation and management depending on traffic intensity. There are some simu-lation models that are developed and implemented in AnyLogic. These models relate to adaptive transport flow control algo-rithms such as soft programming of traffic lights using fuzzy logic; queue-out; search for discontinuities in a transport flow; search optimization using Webster's formula; direct minimization of transport delays in the simulation process; soft program-ming of traffic lights using fuzzy logic. During simulation modeling, including traffic conditions at the actual metropolis intersections, the author compares a possi-ble effect from applying the above adaptive algorithms with the operation of a traffic light with a fixed phase duration for dif-ferent traffic load. The paper presents diagrams of efficiency bounds of the considered algorithms in a wide range of parameter changes. The compared algorithms are sorted by the effect of the intersection capacity in the received initial data ranges. The simulation results show that the installation of adaptive control systems allows reducing car standing time (engine load, gasoline consumption, harmful emissions) in comparison with usual traffic lights at average from 5% to 50%. The optimization principle of constructing adaptive control shows a much bigger effect of increasing intersection capacity comparing with the work of algorithms such as “passing queues” and “break searching” in a wide range of changes in traffic flow intensities. The traffic light algorithm with fuzzy logic occupies an intermediate position. The “sensitivity analysis” experiment in AnyLogic demonstrates a fairly flat dependence of the transport flow optimization criterion from the optimal intensity value of the passing vehicles.
4. CAD integration for logic synthesis using global optimization [№1 за год]
Authors: P.N. Bibilo, V.I. Romanov
Visitors: 385
The paper proposes a technology for designing digital devices. This technology allows logical modeling of VHDL descriptions of combina-tional logic, forming the corresponding systems of Boolean functions, their logical optimizing and synthesizing logic circuits in various tech-nological libraries of logic elements. The software integration within this technology is based using scripts and BAT files that are supported by modern CAD systems. The source VHDL descriptions can set algorithmic and functional descriptions. They are truth tables of completely or noncompletely specified Boolean function systems, systems of partial Boolean functions, systems of disjunctive normal forms, descriptions of multilevel log-ical equations. In addition, structural descriptions of logic circuits synthesized in various target technological libraries might also be used as source VHDL descriptions. In this case, they are redesigned into another basis of logical elements. The transition from VHDL descriptions to systems of Boolean functions is based on logical simulation for all possible sets of input varia-bles. Logical optimization includes using of powerful programs of joint and separate minimization of Boolean function systems in the class of disjunctive normal forms, as well as programs of minimization of multilevel BDD representations (BDD – Binary Decision Diagram) of Boolean function systems based on Shannon’s expansion. A user only needs to specify a VHDL source description, a logical optimization method and a target library of logic elements used in the LeonardoSpectrum synthesizer. The required BAT file is generated automatically. The file provides synthesis using global logic optimization. The user can assess the solution found by comparing with another one that the LeonardoSpectrum synthesizer obtained from the original de-scription without prior optimization.
5. On the application of greedy algorithms in some problems of discrete mathematics [№1 за год]
Author: V.A. Boykov
Visitors: 245
The algorithms that are based on the idea of local optimality seem natural and tempting when solving optimization problems. However, the optimization problems discussed in the paper are multistage. In this case, the obtaining an optimal solution in a multistage problem by greedy algorithms is not guaranteed generally. This fact is demonstrated by the examples of solving a transport problem, the problem of the shortest distance between cities on a given road network, and the traveling salesman prob-lem. The research objects are greedy algorithms applied to solving the same problems described in this paper. The paper gives an example of a paradoxical solution of a small dimension transportation problem. When solving the prob-lem, one of greedy algorithms constructs a product transportation plan. However, this plan is not optimal and has a paradoxical property. Namely, no transportation by the route that is the cheapest in the optimal plan. The optimal solution of the considered problem is given by mathematical package Mathcad. The fact that the greedy algorithm does not show the optimal path is shown on the example of the shortest distance problem. Three counterexamples on Euclidean graphs show that it is impossible to obtain an optimal route even when calculating options several steps ahead. The third example of applying the greedy algorithm to solve the traveling salesman problem is the nearest city method. The method describes the sequential construction of the Hamiltonian cycle. The above version of the algorithm is secured from ob-taining non-connected graphs during a solution process. Further, the length of the Hamiltonian cycle is used as an upper bound when implementing the simplest version of the branch and bound method. The program made in Mathcad checks the optimality of the obtained solution. In the considered examples, the solutions obtained by greedy algorithms are used as an initial approximation for further op-timization of the target function.
6. Using the Bayes' theorem within software quality evaluation according to ISO/IEC 9126 standard [№1 за год]
Authors: D.P. Burakov , G.I. Kozhomberdieva
Visitors: 335
The paper discusses a way to use the approach based on well-known Bayes rule to evaluate software quality according to quali-ty model and evaluation process described in the ISO/IEC 9126 standard. In addition, it briefly describes software quality mod-els and evaluation process that are proposed by the abovementioned standard, as well as by the improved ISO/IEC 25010:2011 standard. The authors define the field of using the proposed approach during the evaluation process. The software quality evaluation is presented as a probability distribution on a set of hypotheses that software quality has reached one of the predefined quality levels proposed by the model. The Bayes' formula is used to build a posteriori probability distribution based on revised and refined during quality evaluation a priori probability distribution that is defined before evalua-tion. The source data for calculating probabilities is the results of measurement of heterogeneous quality metrics for arbitrary set of quality attributes that are specified in the software quality model. The proposed approach allows using both directly measured metrics and the metrics estimated by experts. In fact, the ap-proach gives reasonable software quality evaluation even if there are incomplete, inaccurate and inconsistent quality metrics.
7. Basic principles of creating design and control automation systems in engineering production systems [№1 за год]
Authors: Burdo G.B., Semenov N.A.
Visitors: 215
Modern high-tech engineering and instrument making are high-tech production. They have a number of features that determine the specifics of the processes in them. Therefore, the study of these features is quite relevant and in demand nowadays. The paper presents the results of work aimed at identifying the processes performed in production systems, their automation and construction of effective decision-making algorithms. There is a classification of the types of processes performed in mechanical engineering production systems, the criteria for evaluating process effectiveness. The abovementioned processes are investigated as the life cycle processes at the stages of product design and manufacturing. The authors consider six directions of improving decision-making procedures during process performance in a production system. It is established that decision-making should be based on their certain evaluation criteria. It is proposed that such fundamen-tal criterion should be product quality, which determines product competitiveness in a certain price range. Product quality and timing are determined by process improvements, as well as by the structure of production system tech-nological units. Therefore, the paper considers the criteria that evaluate the structure of technological units. A systematic approach integrates the processes in production systems. Decision-making algorithms are implemented using artificial intelligence.
8. Forecasting of engineering system development based on their morphology when using fundamental knowledge banks [№1 за год]
Author: Butenko D.V.
Visitors: 151
This paper describes the use of technologies in engineering creativity as a general attractor of scientific and educational activi-ties. Engineering creativity as a discipline is based on the fundamental laws of structuring, functioning and development of sys-tems that are of high priority for new solutions in any field of knowledge. The paper proves the need for using these laws on the example of chemistry and chemical technology. This is implied by the requirements of obtaining practically suitable technical and technological solutions that demonstrate completely new states of the designed systems and technical products. The formal-ization of information representation in this field of knowledge determines its application in chemistry. The active use of modern computer technologies allows effective solving of basic problems of general laws of technology structure and development. They include the establishment and application of isomorphic regularities for different technical ob-jects, which in turn are an objective basis for discoveries, inventions and technology improvement. The paper considers similar modern developments, shows their advantages and disadvantages and presents the author's intel-lectual technology of using these regularities in chemical technology in combination with the tools of fundamental knowledge automated banks. The described results show general prospects of technical creativity technologies. It is a possibility of obtain-ing patentable results of intellectual activity with a high degree of novelty and competitiveness, which might be increased through modern computing.
9. Fuzzy set approach for IT project task management [№1 за год]
Authors: A.R. Diyazitdinova, N.I. Limanova
Visitors: 445
Resource distribution and allocation problems are complex multi-criteria tasks. Therefore, the problem of development of effec-tive and universal technologies of work assignment among performers turns out to be challenging in software project manage-ment. One of the possible solutions to increase the relevance of project management decision-making in software development companies might be fuzzy logic. It allows processing semi-structured and inaccurate information using a natural language. The paper proposes a model of fuzzy production system to manage IT project tasks that allows operating natural language categories to improve the efficiency of decision making under uncertainty and cost cutout in the extreme. The authors consider software product development features; develop a typical logic of IT project tasks management process; prove fuzzy logic tech-nology application reasons are for project management. Implementation of fuzzy logic mathematical tools technique allows a project manager to operate variables represented in quality categories without transferring to mean values that enables decision-making quality increase. The paper considers a problem of task (ticket) development performance evaluation. There are derived six input linguistic variables and one output. There are developed term sets and membership functions for each of them. The built expert rule base includes 81 production rules. A model of fuzzy logic production system model for tasks management has been implemented us-ing Fuzzy Logic Toolbox for MatLab. The Mamdani algorithm has been used for fuzzy inference. The provided results of the model functioning would be useful for IT project managers.
10. The methodology and algorithms of aerial object classification by the decision support system under intense information influence [№1 за год]
Authors: Dopira R.V., A.V. Getmanchuk, Potapov A.N., M.V. Semin, V.Yu. Semenov
Visitors: 225
The paper considers the development of methodology and algorithms for classification of aerial objects by a decision support system of the automated control system under intensive information influence. In case of such influence, the signs of system information overload are the amount of data on the air situation (marks from aerial objects) and the information quality. When solving the problem of object classification according to the catalog under parametric uncertainty and class intersection, the use of the sequential normalization procedure based on the entropy maximization principle allows obtaining the least doubtful dis-tribution of probabilities of classifying each of the objects to known or new classes. The paper proposes a combination of the basic method with the basic principles of the methods of split up standards and cluster analysis. The combination allows improving classification characteristics. The basis of the developed methodology of aerial objects classification by a decision support system under intensive information influence is the introduction of the con-cept of parametric space into the basic method, as well as the representation of classification objects and classes from the cata-log of reference values. At the same time, each of the main stages of the methodology analyzes the mutual location of the pro-cessing objects relative to each other, as well as relative to the classes from the catalog of reference values. The classification matrix is presented in the form of a set of dynamic lists. It allows reducing computational complexity while excluding matrix zero elements from processing and not allocating memory to store them. The functionality of processing classification results is extended. There is a possibility to fill in the catalog of reference values with the latest information. The decision support system, which implements the new methodology, allows the automated control system staff to assess the situa-tion in detail and to adjust the automated control system work as the empirical knowledge is formed.
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