bluuebunny/crossref_metadata_2025_split huggingface dataset:
Classes of Dynamic Systems with Various Combinations of Multipliers in Their Reciprocal Polynomial Right Parts
Authors: Andreeva I A 
Published: December 2021

Abstract
A family of differential dynamic systems is considered on a real plane of their phase variables x, y. The main common feature of systems under consideration is: every particular system includes equations with polynomial right parts of the third order in one equation and of the second order in another one. These polynomials are mutually reciprocal, i.e., their decompositions into forms of lower orders do not contain common multipliers. The whole family of dynamic systems has been split into subfamilies according to the numbers of different reciprocal multipliers in the decompositions and depending on an order of sequence of different roots of polynomials. Every subfamily has been studied in a Poincare circle using Poincare mappings. A plan of the investigation for each selected subfamily of dynamic systems includes the following steps. We determine a list of singular points of systems of the fixed subfamily in a Poincare circle. For every singular point in the list, we use the notions of a saddle (S) and node (N) bundles of adjacent to this point semi trajectories, of a separatrix of the singular point, and of a topo dynamical type of the singular point (its TD – type). Further we split the family under consideration to subfamilies of different hierarchical levels with proper numbers. For every chosen subfamily we reveal topo dynamical types of singular points and separatrices of them. We investigate the behavior of separatrices for all singular points of systems belonging to the chosen subfamily. Very important are: a question of a uniqueness of a continuation of every given separatrix from a small neighborhood of a singular point to all the lengths of this separatrix, as well as a question of a mutual arrangement of all separatrices in a Poincare circle Ω. We answer these questions for all subfamilies of studied systems. The presented work is devoted to the original study. The main task of the work is to depict and describe all different in the topological meaning phase portraits in a Poincare circle, possible for the dynamical differential systems belonging to a broad family under consideration, and to its numerical subfamilies of different hierarchical levels. This is a theoretical work, but due to special research methods it may be useful for applied studies of dynamic systems with polynomial right parts. Author hopes that this work may be interesting and useful for researchers as well as for students and postgraduates. As a result, we describe and depict phase portraits of dynamic systems of a taken family and outline the criteria of every portrait appearance.
On the UPMSat-2 Attitude Determination and Control Subsystem’s magnetometers integration
Authors: Rodríguez-Rojo Elena , Cubas Javier , Pindado Santiago 
Published: December 2021

Abstract
In the present work, a method for magnetometer calibration through least squares fitting is presented. This method has been applied over the magnetometer’s data set obtained during the integration tests of the Attitude Determination and Control Subsystem (ADCS) of UPMSat-2. The UPMSat-2 mission is a 50-kg satellite designed and manufactured by the Technical University of Madrid (Universidad Politécnica de Madrid), and finally launched in September 2020. The satellite has three fluxgate magnetometers (one of them experimental) whose calibration is critical to obtain correct measurements to be used by the ADCS. Among several mathematical methods suitable to obtain the calibration parameters, an ordinary least squares fitting algorithm is selected as a first step of the calibration process. The surface estimated is an ellipsoid, surface represented by the magnetometer’s measures of the Earth magnetic field in a point of the space. The calibration elements of the magnetometers are related to the coefficients of the estimated ellipsoid.
FDS simulation of smoke backlayering in emergency lay-by of a road tunnel with longitudinal ventilation
Authors: Weisenpacher P , Glasa J , Valasek L , Kubisova T 
Published: December 2021

Abstract
This paper investigates smoke movement and its stratification in a lay-by of a 900 m long road tunnel by computer simulation using Fire Dynamics Simulator. The lay-by is located upstream of the fire in its vicinity. The influence of lay-by geometry on smoke spread is evaluated by comparison with a fictional tunnel without lay-by. Several fire scenarios with various tunnel slopes and heat release rates of fire in the tunnels without and with the lay-by are considered. The most significant breaking of smoke stratification and decrease of visibility in the area of the lay-by can be observed in the case of zero slope tunnel for more intensive fires with significant length of backlayering. Several other features of smoke spread in the lay-by are analysed as well. The parallel calculations were performed on a high-performance computer cluster.
Spectral radius of the Harary matrix of the join product of regular graphs1
Authors: Medina Luis , Trigo Macarena 
Published: December 2021

Abstract
The distance between two vertices is equal to the number of edges on the shortest path connecting them. The Harary matrix of a simple, undirected, connected and unweighted graph of n vertices is an nonnegative matrix of order n, such that the (i, j)-entry is equal to the reciprocal distance between the vertices vi
and Vj
if the vertices are different and zero if are equal. In this work we found bounds for the spectral radius of the Harary matrix of the join product of regular graphs.
Non-smooth Modeling and Variable Structure Control of a Class of Hybrid Dynamical Systems
Authors: Bin Salamah Yasser A. 
Published: December 2021

Abstract
In this work, we propose a modeling formulation and controller design for a class of hybrid dynamical systems. In this formulation, a switching dynamical system is modeled as a dynamical system with discontinuous right hand side. More specifically, the system is transformed to a nonlinear system with discontinuous nonlinearities. Then, a synthesis of feedback linearization and sliding mode control is employed for output tracking control problem. Application and implementation of this approach is illustrated via a chemical process example.
Analytical modelling of a novel test for determination of porosity and permeability of porous materials
Authors: Torrent R J , Zino G O 
Published: December 2021

Abstract
Porosity and permeability are important properties of porous materials, such as rocks and concrete. This paper presents the physical-mathematical modelling of a novel test, based on one previously developed by one of the authors (standardized in Switzerland, Japan and China) for measuring the air-permeability of concrete structures. In the present case, a cylindrical specimen is placed inside an air-tight cell, subjected to an initial vacuum pressure P
0, which is afterwards isolated from the pump. The rate of pressure increase (due to the extraction of air originally at atmospheric pressure Pa
) is related to the coefficient of permeability of the material whilst the final pressure attained is a function of the porosity (total amount of air extracted). The analysis assumes a unidirectional radial flow of air, which can be achieved by a special serial three-chamber vacuum cell (with pressure regulation of the external chambers) or by an air-tight sealing of the extreme faces of the cylinder. The analysis is developed under the assumption of viscous laminar flow. To account for the molecular diffusion flow, the test can be performed under vacuum (P
0 ≪ Pa) and under overpressure (P
0 ≫ Pa
), enabling the application of the Klinkenberg correction to get the intrinsic coefficient of permeability.
Generalized IBL models for gravity-driven flow over inclined surfaces
Authors: D’Alessio Serge , Mastrogiacomo Jon-Paul , Pascal Jean-Paul 
Published: December 2021

Abstract
In this investigation we propose several generalized first-order integral-boundary-layer (IBL) models to simulate the two-dimensional gravity-driven flow of a thin fluid layer down an incline. Various cases are considered and include: isothermal and non-isothermal flows, flat and wavy bottoms, porous and non-porous surfaces, constant and variable fluid properties, and Newtonian and non-Newtonian fluids. A numerical solution procedure is also proposed to solve the various model equations. Presented here are some results from our numerical experiments. To validate the generalized IBL models comparisons were made with existing results and the agreement was found to be reasonable.
On the satellite attitude determination using simple environmental models and sensor data
Authors: Porras-Hermoso Angel , Cubas Javier , Pindado Santiago 
Published: December 2021

Abstract
Attitude determination represents a fundamental task for most of the spacecrafts. It relies on three basic aspects: 1) sensors selection, 2) relevant environmental conditions estimation, and 3) algorithms that relate the sensor measurements to the expected conditions in the reference frame. Each one has its own impact on the accuracy that the system can achieve. Besides, two factors stand out above the others in terms of accuracy: 1) sensor quality (calibration, range, etc), and 2) precision of the environmental models. The computation of the satellite attitude needs at least two independent measurements (magnetometers, solar sensors...), whit their corresponding simulated measurements in the reference frame. Nevertheless, the number of measurements can be reduced to one if the satellite attitude is constrained. This paper describes a procedure to calculate satellites’ attitude and the main environmental models used (Earth magnetic model, Sun position model, Albedo model), including orbit propagation. This methodology can be extended to measure the performance of a sensor if the satellite attitude can be derived from other measurements and satellite constrains. The methodology is checked with data from the UPMSat-2 mission (launched in September 2020 within the VEGA VV16 mission). This is a 50-kg satellite designed and developed at the Universidad Politécnica de Madrid (UPM).
Nonexistence of global solutions for damped abstract wave equations with memory
Authors: Esquivel-Avila Jorge A. 
Published: December 2021

Abstract
We consider a class of abstract nonlinear wave equations with memory and linear dissipation. We give sufficient conditions in terms of the nitial data to prove the nonexistence of global solutions. We improve recent results that have studied this problem for viscoelastic wave, Kirchhoff and Petrovsky equations with positive initial energy values.
Network analysis of nanoscale energy conversion processes
Authors: Einax Mario 
Published: December 2021

Abstract
Energy conversion in nanosized devices is studied in the framework of state-space models. We use a network representation of the underlying master equation to describe the dynamics by a graph. Particular segments of this network represent input and output processes that provide a way to introduce a coupling to several heat reservoirs and particle reservoirs. In addition, the network representation scheme allows one to decompose the stationary dynamics as cycles. The cycle analysis is a convenient tool for analyse models of machine operations, which are characterized by different nanoscale energy conversion processes. By introducing the cycle affinity, we are able to calculate the zero-current limit. The zero-current limit can be mapped to the zero-affinity limit in a network representation scheme. For example, for systems with competing external driving forces the open-circuit voltage can be determined by setting the cycle affinity zero. This framework is used to derive open-circuit voltage with respect to microscopic material energetics and different coupling to particle and temperature reservoirs.
Models of predictive modeling on the example of a gas turbine
Authors: Echkina E. , Lvov V. 
Published: December 2021

Abstract
The ability to accurately predict the operation of a particular mechanism and, on the basis of this, estimate the equipment life is a very important task. The amount of losses of the enterprise can depend on such study, as well as the health of many people whose lives depend on the health of the working installation. As part of this work, the main time series models were considered and the most suitable for the study was selected. The operation of a gas turbine was studied and a forecast was made. On the basis of the study, linear regression, ARIMA and moving average models were built and evaluated.
Problems of increasing the efficiency of using fixed and working capital of petrochemical enterprises
Authors: Galeeva G M 
Published: December 2021

Abstract
The article discusses topical issues of analysis of the state and improving the quality of management of the structure of fixed and working capital of enterprises of the petrochemical complex. Evaluation of indicators affecting the efficiency of their use made it possible to determine the directions for improving the process of forming the value of fixed and circulating assets of petrochemical enterprises. In conclusion, the authors highlight the successful practices of enterprise asset management.
Human machine interface (HMI) based on a multi-agent system in a water purification plant
Authors: Mendoza E. , Andramuño J. , Núñez J. , Córdova L. 
Published: December 2021

Abstract
The applications of multi-agent systems (MAS) are growing increasingly in the industrial field due to the advantages inherent to their characteristics and properties, the use of distributed automation architectures, which have satisfactorily solved control problems that its complexity and dynamic behavior have not been properly resolved with other approaches under these conditions, intelligent agents must meet the requirements of current automation systems, such as autonomy, flexibility, reconfiguration, in concurrent and collaborative systems, which traditionally do not have been designed to satisfy these characteristics. In the present work, a distributed architecture is proposed for the design of an intelligent agent in a Human-Machine Interface (HMI) for the supervision of the filtering stage of a water purification plant, characterized by the ability to collaborate with the other agents that make up the entire plant. For the projection and design of the system, the Unified Modeling Language (UML) and Petri nets (PN) are used for the simulation and validation of the system, and the implementation of the agent from macros in C language, starting from a methodology of multi-agent design that is applied in this document. The implementation of the intelligent agent in an HMI associated with multi-agent architecture, which allowed to evaluate its behavior through the analysis of the properties of the PN and experimental tests, demonstrating the correct operation of the device, response times and its dynamic behavior based on of the functional requirements of the water purification plant and comparisons with similar works.
Intelligent multi-agent architecture for a supervisor of a water treatment plant
Authors: Mendoza E. , Andramuño J. , Núñez J. , Córdova L. 
Published: December 2021

Abstract
The rapid development of Information and Communication Technologies (ICT) and high-capacity hardware components make it necessary to achieve a strong integration of automatic systems based on new paradigms on intelligent distributed architectures, where require highly complex supervision and control tasks, due to the generated requirements of the new production systems, the high number of variables to control and the advancement of technologies, especially in industries where continuous processes have been established. In the present work, a distributed hierarchical modular architecture is proposed for a supervision system, based on multi-agent systems (MAS), oriented to the management of processes in the filtration stage of a water purification plant, using a methodology to the implementation of intelligent agents that allow to project, design, verify and validate the system. This methodology is fundamentally based on the use of the Unified Modeling Language (UML) for its projection and Petri nets (PN) for the simulation and validation of properties, which allows to guarantee the modularity, flexibility, and robustness of the proposed system. The architectures of the intelligent agents in the different programmable devices are modeled and simulated to achieve an adequate interaction and collaboration, allowing to reduce the conflicts that may be generated between them. The evaluation of the distributed architecture focuses on the fulfillment of the functional requirements and evaluation metrics, which, through the analysis of the properties of the Petri net, allows to determine the correct operation of the system and its dynamic behavior in the face of unforeseen situations at different levels of automation.
A Generalized Pattern Search Algorithm Methodology for solving an Under-Determined System of Equality Constraints to achieve Power System Observability using Synchrophasors
Authors: Theodorakatos Nikolaos P. , Lytras Miltiadis , Babu Rohit 
Published: December 2021

Abstract
The impact of the generalized pattern search algorithm (GPSA) on power system complete observability utilizing synchrophasors is proposed in this work. This algorithmic technique is an inherent extension of phasor measurement unit (PMU) minimization in a derivative-free framework by evaluating a linear objective function under a set of equality constraints that is smaller than the decision variables in number. A comprehensive study about the utility of such a system of equality constraints under a quadratic objective has been given in our previous paper. The one issue studied in this paper is the impact of a linear cost function to detect optimality in a shorter number of iterations, whereas the cost is minimized. The GPSA evaluates a linear cost function through the iterations needed to satisfy feasibility and optimality criteria. The other issue is how to improve the performance of convergence towards optimality using a gradient-free mathematical algorithm. The GPSA detects an optimal solution in a fewer number of iterations than those spent by a recursive quadratic programming (RQP) algorithm. Numerical studies on standard benchmark power networks show significant improvement in the maximum observability over the existing measurement redundancy generated by the RQP optimization scheme already published in our former paper.
Analysis of the error distribution density convergence with its orthogonal decomposition in navigation measurements
Authors: Vorokhobin Igor , Zhuravska Iryna , Burmaka Igor , Kulakovska Inessa 
Published: December 2021

Abstract
Modern trends towards the expansion of online services lead to the need to determine the location of customers, who may also be on a moving object (vessel or aircraft, others vehicle – hereinafter the “Vehicle”). This task is of particular relevance in the fields of medicine – when organizing video conferencing for diagnosis and/or remote rehabilitation, e.g., for post-infarction and post-stroke patients using wireless devices, in education – when organizing distance learning and when taking exams online, etc. For the analysis of statistical materials of the accuracy of determining the location of a moving object, the Gaussian normal distribution is usually used. However, if the histogram of the sample has “heavier tails”, the determination of latitude and longitude’s error according to Gaussian function is not correct and requires an alternative approach. To describe the random errors of navigation measurements, mixed laws of a probability distribution of two types can be used: the first type is the generalized Cauchy distribution, the second type is the Pearson distribution, type VII. This paper has shown that it’s possible obtaining the decomposition of the error distribution density using orthogonal Hermite polynomials, without having its analytical expression. Our numerical results show that the approximation of the distribution function using the Gram-Charlier series of type A makes it possible to apply the orthogonal decomposition to describe the density of errors in navigation measurements. To compare the curves of density and its orthogonal decomposition, the density values were calculated. The research results showed that the normalized density and its orthogonal decomposition practically coincide.
Lower bound for the spectral radius of the starlike trees
Authors: Arrizaga-Zercovich Rubí 
Published: December 2021

Abstract
A tree is a connected acyclic graph. A tree is called a starlike if exactly one of its vertices has degree greater than two. Let λι be the largest eigenvalue of the adjacency matrix of a starlike tree. In this work, we obtain a lower bound for the spectral radius of a starlike tree. This bound only depends of the maximum degree of the vertices.
High-speed camera test of newly developed igniter’s charges for artillery rounds
Authors: Plachá A , Recko J 
Published: December 2021

Abstract
The article presents the results of the high-speed camera test of newly developed igniter’s charges for artillery rounds. The test was performed to take a closer look at the ignition process of mixtures, that is, to check the time-to-ignition of samples, and to assess the presence and quantity of solid igniting particles (if any). Five compositions were tested: Three of them contained the new igniter’s charges developed by the Military Institute of Armament Technology, and the other two contained black powder in different granularity classes as a comparison mixture. This article presents the collated test results.
The influence of knot types on rope static tensile strength
Authors: Plachá A , Ruliński P. , Rybakiewicz L. 
Published: December 2021

Abstract
The choice of material, type of braid and rope parameters are a broad issue of great importance in the designing process. An equally important issue is the proper selection of knot type used for attaching the rope to the other elements of a structure, as this is a critical point accumulating major stresses. Inappropriate tying of a rope may decrease its tensile strength by over 50%; therefore, it is an important issue in terms of structural strength. This article investigates different tying configurations of the same rope and shows the influence of knot types on rope static tensile strength.
CNF-SAT modelling for banyan-type networks and its application for assessing the rearrangeability
Authors: Ohta S 
Published: December 2021

Abstract
A banyan-type network is a switching network, which is constructed by placing unit switches with two inputs and two outputs in s (s > 1) stages. In each stage, 2
n – 1 (n > 1) unit switches are aligned. Past studies conjecture that this network becomes rearrangeable when s ≥ 2n-1. Although a considerable number of theoretical analyses have been done, the rearrangeability of the banyan-type network with 2n – 1 or more stages is not completely proved. As a tool to assess the rearrangeability, this study presents a CNF-SAT (conjunctive normal form - satisfiability) modelling scheme for banyan-type networks. In the proposed scheme, the routing is formulated to a SAT problem represented in CNF. By feeding the problem to a SAT solver, it is found whether the problem is satisfiable or unsatisfiable. If the problem is unsatisfiable for a certain request, the network is not rearrangeable. By contrast, if the problem is satisfiable for any requests, the network is rearrangeable. This study applies the CNF-SAT modelling scheme to various configurations of 2n – 1 stage banyan-type networks. These networks are assessed for rearrangeability by solving the SAT problems. The proposed method will be helpful to conduct future theoretical studies on banyan-type networks.