Advances in Systems Science and Applications <p><strong><em>Advances in Systems Science and Applications </em></strong><strong>(<em>ASSA</em>) </strong>is an international peer-reviewed open-source online academic journal. Its&nbsp;scope covers all major aspects of systems (and processes) analysis, modeling, simulation, and control, ranging from theoretical and methodological developments to a large variety of application areas. Survey articles and innovative results are also welcome.</p> <p>ASSA is aimed at the audience of scientists, engineers and researchers working in the framework of these problems. ASSA should be a platform on which researchers will be able to communicate and discuss both their specialized issues and interdisciplinary problems of systems analysis and its applications in science and industry, including data science, artificial intelligence, material science, manufacturing, transportation, power and energy, ecology, corporate management, public&nbsp;governance, finance, and many others.</p> International Institute for General Systems Studies, Pennsylvania, USA en-US Advances in Systems Science and Applications 1078-6236 Effect of Fiber Orientation and Residual Stresses on the Structural Performance of Injection Molded Short-Fiber-Reinforced components <p class="MDPI17abstract"><span lang="EN-US">To optimize the strength design of short-fiber injection molding components, a three-dimensional flow and structural analysis simulations were employed. In particular, these Finite Element Analyses (FEA) were based on orthotropic, linear and elastic models including process-induced residual stresses. Through an appropriate interface, the results of injection molding analysis of 35 wt.% fiber reinforced polyphthalamides (PPA) manifold block used in hot-water fluid engineering application are transferred to the structural analysis software. In particular, Autodesk Moldlfow software was used to predict the fiber orientation and the in-cavity residual stresses considering the flow kinetics and moulding parameters. The Abaqus interface for Moldflow was used to translate this data into a form that can be used for the structural analysis. Experimental tests were carried out on the injection moulded component in order to evaluate the internal burst pressure values. The burst strength of the component was then compared with those predicted by the numerical analysis. The computations are found in good agreement with the experimental results.</span></p> Giorgio Ramorino Silvia Cecchel Giovanna Cornacchia ##submission.copyrightStatement## 2020-06-30 2020-06-30 20 2 1 19 10.25728/assa.2020.20.2.782 Global Stability Analysis of Typhoid Fever Model <p>We analyze with four compartments a deterministic nonlinear mathematical model of typhoid fever transmission dynamics. Using the Lipchitz condition, we verified the existence and uniqueness of the model solutions to establish the validity of the model and derive the equilibria states of the model, i.e. disease-free equilibrium (DFE) and endemic equilibrium (EE). The computed basic reproductive number R<sub>0</sub> was used to establish that the disease-free equilibrium is globally asymptotically stable when its numerical values are less than one while the endemic equilibrium is locally asymptotically stable when its values are greater than one. In addition, the Lyapunov function was applied to investigate the stability property for the (DFE). The model was numerically simulated to validate the results of the analysis.</p> Olumuyiwa James Peter Ajimot Folasade Adebisi Michael Oyelami Ajisope Fidelis Odedishemi Ajibade Adesoye Idowu Abioye Festus Abiodun Oguntolu ##submission.copyrightStatement## 2020-06-30 2020-06-30 20 2 20 31 10.25728/assa.2020.20.2.792 Dynamic Adaptation of Genetic Algorithm for Solving Routing Problems on Large Scale Systems <p>This paper is devoted to the implementation of the dynamic adaptation procedure for the genetic algorithm used for solving large-scale travelling salesman problem. This procedure serves to obtain more profitable solutions by a fixed operating time. In order to evaluate effectiveness of new approach computational experiments were performed on well-known problem instances from TSPLib library. As a result, generated solutions reduce the length of the routing plans in considered problem instances compare to classical genetic heuristics. By that, we show how to use the property of time inconsistency of heuristics to get better solutions. New criteria for estimating the efficiency of heuristics algorithms called experimental level of time consistency is introduced.</p> Viktor Zakharov Alexander Mugaiskikh ##submission.copyrightStatement## 2020-06-30 2020-06-30 20 2 32 43 10.25728/assa.2020.20.2.821 Influence Assessment of Intelligent Unmanned Ground Vehicles on the Transport Network State <p>This article is devoted to econometric analysis of the results of experiments conducted with two agent-based models, which describe the movement of ground vehicles. There are two types of road users in these models: manned ground vehicles (MGV) and unmanned ground vehicles (UGV). In the first model, the main difference between UGV and MGV is an ability to exchange massages between UGV for transmitting information about extreme situations, which allows them to adjust speed and direction of movement. In the second model, in addition to the above differences, UGV have an additional advantage, namely, the ability to intelligently assess density of traffic flow for efficient maneuvering. In these models, at a given roundabout, traffic characteristics such as output stream traffic and the number of traffic accidents are analyzed. The main task of the econometric analysis is to study dependence of these traffic characteristics on the model parameters such as average vehicle speed, input flow rate, message exchange rate between UGV, and the impact of the effect obtained from the implementation into UGV ability of intelligent estimation of traffic flow density.</p> Andranik Akopov Nerses Khachatryan Fedor Belousov ##submission.copyrightStatement## 2020-06-30 2020-06-30 20 2 44 55 10.25728/assa.2020.20.2.859 Numerical Methods for Constructing Solutions of Functional Differential Equations of Pointwise Type <p>The article discusses construction of traveling wave type solutions for the Frenkel-Kontorova model on the propagation of longitudinal waves. For the first time, based on the&nbsp;existence and uniqueness theorem of traveling wave type solutions, as well as the approximation theorem, a complete family of traveling wave type solutions is constructed in the form of&nbsp;subfamilies of bounded solutions (horizontals) and unbounded solutions (verticals).</p> Armen Levonovich Beklaryan ##submission.copyrightStatement## 2020-06-30 2020-06-30 20 2 56 70 10.25728/assa.2020.20.2.878 Comparison of Two Dynamic Models of Economic Growth <p>Two dynamic models of economic growth with the same balance equation are considered.&nbsp; First, we establish the solution of the Harrod-Domar model with time-dependent coefficient of the capital intensity of income growth.&nbsp;(Previously, the only constant coefficients were considered.)&nbsp;Second, we show that in the Solow model with the Cobb-Douglas production function, the capital intensity of income growth depends on time.&nbsp;Comparing these models, we demonstrate the effectiveness of the setting optimal control problems (maximization of the integral discounted utility function) in the extended the Harrod-Domar model.</p> Alexander Petrovich Chernyaev ##submission.copyrightStatement## 2020-06-30 2020-06-30 20 2 71 81 10.25728/assa.2020.20.2.886 Plasma Control in Tokamaks <p>The plasma magnetic control systems for ITER (International Thermonuclear Experimental Reactor) are presented. The systems comprise original engineering solutions for plasma position, current and shape control for the two versions of ITER: ITER-1 and ITER-2, including those designed in V. A. Trapeznikov Institute of Control Sciences of the RAS. It is noted that in ITER-1 the plasma position and shape were controlled by all PF-coils and robust H∞-controllers, while to decrease peaks of control power for suppressing minor disruptions the additional nonlinear circuit was used without significant changes in displacements of the gaps between the plasma separatrix and the first wall. In ITER-2 the special circuit with a fast voltage rectifier was used for plasma vertical speed stabilization about zero, while for plasma current and shape control the special cascade control systems were designed with and without the control channels decoupling, with robust H∞-controllers and predictive model, and with adaptive stabilization of the plasma vertical position as well. To increase the plasma controllability region in the vertical direction the additional horizontal field coils were introduced into the ITER-2 vacuum vessel and the capabilities of the system with the new circuits to control the plasma vertical position at the noise presence were investigated.</p> Yuri Vladimirovich Mitrishkin Nikolay Mikhailovich Kartsev Artem Evgenyevich Konkov Mikhail Ivanovich Patrov ##submission.copyrightStatement## 2020-06-30 2020-06-30 20 2 82 97 10.25728/assa.2020.20.2.892 Student Mixture and Its Machine Learning Applications to PVT Properties of Reservoir Fluids <p>Distribution mixture models are widely used in cluster analysis. Particularly, a mixture of Student t-distributions is mostly applied for robust data clustering. In this paper, we introduce EM algorithm for a mixture of Student distributions, where at the E-step, we apply variational Bayesian inference for parameters estimation. Based on a mixture of Student distributions, a machine learning method is constructed that allows solving regression problems for any set of features, clustering, and anomaly detection within one model. Each of these problems can be solved by the model even if there are missing values in the data. The proposed method was tested on real data describing the PVT properties of reservoir fluids. The results obtained by the model do not contradict the basic physical properties. In majority of conducted experiments our model gives more accurate results than well-known machine learning methods in terms of MAPE and RMSPE metrics.</p> Nikita Volkov Elizaveta Dakhova Semen Budennyy Alla Andrianova ##submission.copyrightStatement## 2020-06-30 2020-06-30 20 2 98 118 10.25728/assa.2020.20.2.899 Structural Change in Multisector Monopolistic Competition Model <p>We present a natural generalization of the Dixit-Stiglitz monopolistic competition model (DSM)&nbsp;— we assume that there is a continuum of industries, each of them described as in DSM, and each characterized with its own elasticity of substitution. Although firms in all industries share the same level of productivity and costs, exogenous technological progress leads to non-trivial reallocations of labor and production to industries with lower elasticities of substitution. Thus the model, despite is simplicity and the absence of additional assumptions about industry structure, generates the structural changes described in the economic growth literature.</p> Igor Pospelov Stanislav Radionov ##submission.copyrightStatement## 2020-06-30 2020-06-30 20 2 119 130 10.25728/assa.2020.20.2.906 Allocation of Limited Resources in a System with a Stable Hierarchy (on the Example of the Prospective Military Communications System) <p>The article is devoted to the formalization of the resource allocation problem in the hierarchical social system, where resources are distributed according to the agent's role in the system. We study the application of a proposed mathematical model to the organization of the special purpose communication network. Also, we propose an algorithm of the automatic partitioning of the radio communication system according to the role of nodes. None of the nodes has complete knowledge about the entire communication system, and the initially unknown information about the purpose of nodes is established in the process of the beacons exchange.</p> Alexander Vladimirovich Kuznetsov ##submission.copyrightStatement## 2020-06-30 2020-06-30 20 2 131 145 10.25728/assa.2020.20.2.910