Advances in Systems Science and Applications 2021-04-01T06:07:37+00:00 Natalya Pavlova Open Journal Systems <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> The Optimal Control of the Vessel’s Automatic Dynamic Positioning System Under Deviation 2021-04-01T06:07:35+00:00 Vadim Kramar Vasilii Alchakov Alexander Osadchenko <p>An optimal algorithm for linear control of the unmanned vessel dynamic positioning system with provision for vessel characteristics, equipment, and the process has been developed. A block diagram for the automatic dynamic positioning system has been suggested which allows presenting a necessary set of devices for its technical implementation.</p> 2021-03-31T00:00:00+00:00 ##submission.copyrightStatement## Purchase Price Control in High-Tech Product Markets under Competition of Suppliers with Multi-Channel Production Capacities 2021-04-01T06:07:36+00:00 Irina E. Selezneva <p>The strategic control of the purchase price for high-tech products and market competition is considered. For this purpose, a new bilateral oligopoly market model is proposed. The new model allows determining the purchase prices for high-tech products under the competition of suppliers with flexible production capacities. Parametric calculations of the purchase prices, the number of competing suppliers and their production capacities are performed depending on the unit price offered by the monopsonist customer. The purchase prices offered by the customers to guarantee the competitiveness of the market are determined. The customers’ optimal pricing policy that will reduce the purchasing costs and/or ensure the existence of competing suppliers in the long run is identified. A possible price reduction for high-tech products when applying this policy is calculated. The ranges of some characteristic market parameters (the capital-output ratio, the rates of order execution and order flow, and the number of potential order sources) for which this policy is efficient are determined.</p> 2021-03-31T00:00:00+00:00 ##submission.copyrightStatement## Design and Comparison of Plasma H∞ Loop Shaping and RGA-H∞ Double Decoupling Multivariable Cascade Magnetic Control Systems for a Spherical Tokamak 2021-04-01T06:07:36+00:00 Yuri Mitrishkin Evgeniia Pavlova Mikhail Patrov <p>The article aims to present an approach to design and compare cascade H<span style="font-size: 11.6667px;">inf</span>&nbsp;loop shaping and essentially new cascade RGA-H<span style="font-size: 11.6667px;">inf</span>&nbsp;double decoupling magnetic control systems for a multivariable dynamical plant, specifically plasma in a vertically elongated tokamak. Identification of the present control closed-loops containing a plasma linear model of a relatively high order for the spherical Globus-M tokamak (Ioffe Institute, St Petersburg, Russia) to derive a low order linear model (without the application of reduction algorithms) as a plant under control is undertaken. A robust H<sub>¥</sub> loop shaping method was applied to the identified model to design a plasma position, current, and shape (6 gaps between the first wall and plasma separatrix) multivariable controller. A structural analysis was done to get the most effective structure of the square plant with the 3rd gap eliminated in the feedback and a separate loop for the plasma current control. The methodology of the relative gain array (RGA) was applied to this structure to choose the proper correspondences between inputs and outputs (pairing), which brought the plant model closer to a decoupling plant (first decoupling in the open plant model). Further, the H<span style="font-size: 11.6667px;">inf</span>&nbsp;adjustment of the control system with the pairing plant and an additional feedback decoupling matrix (second decoupling of the plant model in the feedback) and PI controllers in the feedback gave increased control system accuracy while tracking references. Comparison of the two control systems designed has shown that double decoupling gives higher performance accuracy and a less robust stability margin, while the robust loop shaping method allows the stability margin to be increased but gave less accurate control of the gaps.</p> 2021-03-31T00:00:00+00:00 ##submission.copyrightStatement## Decoupling Model-Based Fuzzy Logic Control of Room Temperature and Humidity 2021-04-01T06:07:36+00:00 Snejana Yordanova <p>The control of room temperature and humidity is important for ensuring of the necessary indoor human comfort for optimal work capacity and effective rest. The plant nonlinearity and the variables coupling require intelligent control techniques in order to satisfy the high performance demands. The present paper suggests a procedure for the design of a simple for industrial implementation fuzzy logic controller on the principle of parallel distributed compensation (PDC) that consists of linear local decoupling two-variable controllers. It is based on a Takagi-Sugeno-Kang (TSK) plant model, derived from experimentally obtained plant step responses using expert knowledge and parameter optimisation via genetic algorithms. The design is applied for the control of the temperature and the relative humidity of a laboratory air-conditioning system. The PDC system outperforms an existing Mamdani two-variable control system with adaptive properties in shorter settling time, higher robustness and reduced overshoot, estimated from simulations.</p> 2021-03-31T00:00:00+00:00 ##submission.copyrightStatement## Formularization Method for Calculating the Breakaway and Break-in Points and the Corresponding Gain of Root Locus Graphs 2021-04-01T06:07:36+00:00 Hassan Shibly Orwah H. Shibly <p>Break points, break-away and break-in points, are an essential part in root locus technique for single input single output linear invariant control systems. The importance of Break points comes from the fact that at the Break points at least two roots of the characteristic equation of the closed loop control system change their type from real to a complex at the break away point, and from complex to real at break-in point. This change affects the response of the system which can be crucial for some of systems’ applications. The conditions for being a Break point are analysed and a new formulated systematic method for finding the Break points and their corresponding gains is presented. An efficient algorithm was developed and can be solved analytically. There is no mathematical differentiation during calculation, and the algorithm can be programmed easily. The developed algorithm is applicable for any order of transfer function of a linear invariant control system. This method is compared with other common methods to show its merits and effectiveness.</p> 2021-03-31T00:00:00+00:00 ##submission.copyrightStatement## On Uniform Convergence Property of Solutions for Periodic Differential Inclusions with Asymptotically Stable Sets 2021-04-01T06:07:36+00:00 Mikhail Morozov <p>The paper considers a periodic differential inclusion with an asymptotically stable set. The uniform character of convergence of solutions to an asymptotically stable set is established. An exponential estimate is obtained for solutions of a periodic differential inclusion homogeneous in state vector. Examples of control systems leading to consideration of periodic differential inclusions are given. These results can find applications in the stability analysis of control systems with periodic parameters, in particular, servomechanisms whose elements operate on AC, control systems with pulse amplitude modulation, and systems used to solve problems related to investigating vibrations of milling machines.</p> 2021-03-31T00:00:00+00:00 ##submission.copyrightStatement## Enhanced Results on Stability Criteria for Linear Time Delay Systems with Distributed Delay via Relaxed Double Integral Inequality 2021-04-01T06:07:36+00:00 Jeetendra Rajagopal Jeevanandan Balamurugan <p>This paper investigates the matter of stability criteria for linear time delay systems with distributed delay. Firstly, a relaxed double integral inequality is established to estimate the double integral terms appearing within the derivative of Lyapunov-Krasovskii functionals (LKFs) with a triple integral term. Unlike the recently introduced Jensen's inequalities, Wirtinger based integral inequalities, refined Jensen's inequalities and therefore the auxiliary function based integral inequalities the proposed relaxed integral inequality provides large feasible solution region and fewer conservative results. Secondly, by constructing an augmented Lyapunov-Krasovskii functional with a triple integral term, the robust stability criteria for linear time delay systems with distributed delay are given in terms of linear matrix inequalities (LMIs), which may be easily computed by the LMI toolbox of MATLAB. Finally, two numerical examples are performed to indicate the effectiveness of the proposed criterion.</p> 2021-03-31T00:00:00+00:00 ##submission.copyrightStatement## Improving DCP Haze Removal Scheme by Parameter Setting and Adaptive Gamma Correction 2021-04-01T06:07:36+00:00 Cheng-Hsiung Hsieh Yi-Hung Chang <p>Recently, single-image haze removal based on the dark channel prior (DCP), originally proposed by He et. al., has attracted much attention in the image restoration community. This dehazing algorithm, called the DCP scheme here, is well-known to have four main problems in its dehazed images: artifacts, hue distortion, color over-saturation, and halos. In this paper, an improved DCP (IDCP) is proposed to deal with the four aforementioned problems, by setting the model parameters, i.e. scaling factors and window size and smoothing factor of a guided image filter in the DCP scheme. Note that a dehazed image is generally dim and low in contrast. An adaptive gamma correction (AGC) is introduced for dehazed image enhancement. The proposed IDCP and AGC are used to create the IDCP/AGC scheme, in which the IDCP scheme performs haze removal and the AGC enhances the dehazed image. The IDCP/AGC scheme was justified through extensive experiments and compared with the DCP scheme, an optimization-based scheme, and two learning-based schemes on two datasets. The results indicated that the proposed scheme is subjectively and objectively superior to the comparison schemes.</p> 2021-03-31T00:00:00+00:00 ##submission.copyrightStatement## Software for Testability Analysis of Aviation Systems 2021-04-01T06:07:37+00:00 Valentina S. Viktorova Armen S. Stepanyants <p>This paper describes models, methods and software tool for testability analysis of aviation systems. It comprises analytical and programing aspects of calculations of main testability, reliability and availability indices. It presents general description of the software, XML schema of input data and technique of their mapping to the database structure. The procedure for generating the initial data for testability analysis based on the line replaceable units failure modes report is described. Fault tree model for analysis of the built-in test conformity is suggested. Markov models have been created for analyzing reliability and availability, taking into account the features of the built-in test and the specifics of the aircraft operation. An approach to the construction of trends in the operative availability of aviation systems in the inter-maintenance interval is proposed.</p> 2021-03-31T00:00:00+00:00 ##submission.copyrightStatement## Application of the Minimum Principle of a Tikhonov Smoothing Functional in the Problem of Processing Thermographic Data 2021-04-01T06:07:37+00:00 Eugeniy Laneev Natalia Chernikova Obaida Baaj <p>The paper considers a method for correcting thermographic images. Mathematical processing of thermograms is based on the analytical continuation of the stationary temperature distribution as a harmonic function from the surface of the object under study to the heat sources. The continuation is performed by solving an ill posed mixed problem for the Laplace equation in a cylindrical region of rectangular cross-section. The cylindrical area is bounded by an arbitrary surface and plane. The Cauchy conditions are set on the surface-the boundary values of the desired function and its normal derivative. Inhomogeneous conditions of the first kind are set on the side faces of the cylinder. The problem is the inverse of the corresponding mixed problem for the Poisson equation. In this paper, an approximate solution of the problem is obtained that is stable with respect to the error in the Cauchy data and inhomogeneity in the boundary conditions. In the course of constructing an approximate solution, the problem is reduced to the Fredholm integral equation of the first kind, which is solved using the minimum smoothing functional principle. The convergence of the approximate solution of the problem is proved when the regularization parameter is matched to the error in the data.</p> 2021-03-31T00:00:00+00:00 ##submission.copyrightStatement##