Software & Systems

Articles of journal № 3 at 2018 year.

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31. Improving the accuracy calculation of time delay automatic control [№3 за 2018 год]
Authors: V.D. Than, Yu.N. Dementev, V.I. Goncharov
Visitors: 3301
The article considers accuracy problems of synthesis automatic control systems (ACS) with time delay. The questions cover the traditional approach based on approximation of a delay element transfer function by a rational fractional expression, as well as the original way that allows keeping an accurate description of the delay element when solving the problems of ACS regulator synthesis. The authors choose the last option, which is based on using a special case of the Laplace transform that provides a transition to the description of dynamical systems in the form of image functions with a real variable. This numerical method makes it possible to obtain discrete models of dynamic systems, combining the advantages of numerical methods and digital computing tools. Based on a numerical method the authors consider three topical problems of synthesis and research of the indicated class systems. The first one is related to a delay element approximation. The paper gives a comparative analysis of the approaches based on segments of the Taylor series, Padé fractions and the numerical method. The advantages of the latter are: higher accuracy and, most importantly, it is possible to redistribute the approximation error in the region of small/large values of time. Within the framework of the second problem the paper shows the possibility of forming and solving the synthesis equation for an automatic control system without approximation of a delay element ensuring the achievement of the potentially possible synthesis accuracy. The third problem reveals the possibilities of the numerical method in estimating the accuracy of automatic control system synthesis and the comparison of several options. The authors propose a variant of estimation that does not require the approximation of the delay element. A result is graphically illustrated and proved by numbers of examples.

32. Modeling brain activity recognizing anagrammatically distorted words [№3 за 2018 год]
Author: Z.D. Usmanov
Visitors: 6299
The object of research are natural language texts the words in which were corrupted by random letter transpositions. The authors analyze the ability of a human brain to accurately recognize the meaning of distorted texts. offer mathematical models how the brain decides the problem. The paper describes a mathematical model that explains how the brain solves the problem in cases when a) the first, b) the last, c) the first and last letters of words remain in their places, and all others are reset arbitrarily and, finally, in the most general case, d) when no letter is fixed and all letters within a word can be placed in any order. The explanation is based on the concept of a word anagram (in the broad sense, the set of its letters arranged in any sequence) as well as on the concept of an anagram prototype. A simplified mathematical model assumes that the brain perceives each anagram separately; recognizes it correctly if it has a single prototype. In the case when there are several such prototypes, the brain automatically selects the one that has the highest frequency of occurrence in texts. The acceptability of this model was tested in English, Lithuanian, Russian and Tajik, as well as in the artificial language such as Esperanto. For all languages, efficiency of the correct recognition of distorted text was at the level of 97–98%. If it is necessary to achieve higher indicators, one can refer to an extended idea in which the brain takes into account couples, and maybe triples of neighboring letter sets.

33. Modeling traffic flows in AnyLogic [№3 за 2018 год]
Authors: Ya.I. Shamlichky, A.S. Okhota, S.N. Mironenko
Visitors: 10516
The article proposes a technique for modeling traffic flows in a simulation environment. The goal was to simulate a section of the road network in Krasnoyarsk. The goal included the following tasks: to gather data on the traffic flow intensity at a site, to develop a simulation model of an intersection. The authors have chosen the AnyLogic modeling environment to solve the problems. The simulation experiment requires the input parameters. I this case, they are the intensity of vehicles arrival and the distribution of vehicles by a direction. The developed simulation model has the following structural elements: road network elements, model agent generation system, vehicle traffic logic blocks, model parameters control elements, and an agent statistics gathering module. The model execution mode allows displaying animation, which is a two-dimensional plan of the simulated system with moving vehicles. In addition, there is a functional for switching between a two-dimensional and three-dimensional system plan. The statistical data take into account the time a vehicle passes a road network segment, as well as the total intersection traffic capacity. The procedure of performing the experiment is a preliminary tuning of a simulation model to the average traffic capacity of the intersection (this usually occurs after a number of vehicles exiting the model using the Sink component reaches 20 or more thousands). Then while changing the time of the traffic lights, the simulation model is started alternately. After finishing a series of runs, follows the calculation of the difference in the mean delay of hard and adaptive regulation, construction of the graphs, and making the conclusions. As a result, we get a simulation model with an experimental technique that can be useful in determining the maximum traffic capacity at traffic intersections, planning road infrastructure, etc.

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