Mathematical Model For Computation Research Articles

Dual-contoured model of cardiovascular system regulation

The purpose of the study is to create a model of the cardiovascular system that gives an adequate description of the processes of hemodynamic regulation for the needs of intensive care. An overview of the most recent significant blood circulation models that take the regulation processes into account is proposed, the peculiarities and limitations of such models are identified. The methods of computational hemodynamics and mathematical modeling are used. A zero-dimensional dynamic mathematical model of cardiovascular system with two regulatory contours suggested by its authors is described. The results of the study are of interest to intensive care doctors in selecting a treatment strategy.

Development and introduction of digital double technology technology in aviation technology

The article is devoted to the analysis of the key features of the effective application of digital twin’s technology in aviation technology. In the theoretical part of the article, the authors define the purpose of developing a digital double, which is to provide replacement or significant reduction of expensive full-scale stands and flight tests through the use of precision and certified computational physical and mathematical models. The structural composition of the technologies included in the concept of the digital double is given. The research part analyzes the use of digital twin’s technology within the unique digital environment of a «Virtual high-tech enterprise», combining a unique practice-oriented training of specialists with the possibility of organizing joint work on projects of information technology improvements. The results of the study consider the components of the 3D CAE platform used by specialists to solve many problems in the field of engineering analysis and the creation of digital twins.

Modeling the Activity of Small and Medium Enterprises using Set Theory

One of the directions of the Strategy for the Development of the Information Society in the Russian Federation for 2017-2030 is elaboration of technology for processing data on the activities of economic entities, as a tool for analyzing economic activity and making decisions based on the most complete amounts of information. The number of small and medium enterprises in certain industries and regions of Russia amounts to tens and hundreds of thousands. The assessment of their performance indicators requires improving methods for the formation and analysis of relevant databases, as well as the development of computer economic and mathematical models. Taking into account the large number of enterprises included in the relevant aggregates, the authors propose a new original approach to the description of their performance indicators. The study aims to develop a methodology for a system analysis of performance indicators of small and medium enterprises using set theory. These indicators are formed on the basis of a combination of different variants of their sets. The authors also consider the interrelations between the indicators characterizing the sets of small and medium enterprises belonging to different size categories, industries and territories. The results of the study can be used to develop technology for processing data on the activities of business entities, as a tool for analyzing economic activity and making decisions. They make it possible to establish patterns and trends in the development of various aggregates of SMEs, substantiate proposals and recommendations for improving their functioning on the basis of the characteristics specific to particular aggregates, and provide a differentiated approach to solving problems of state regulation of entrepreneurship.

INVESTIGATION OF THE GEOMETRIC PARAMETERS OF THE BRAKE PADS OF FREIGHT CARS UNDER HAZARDOUS WEAR

Purpose. This study aims to determine the geometric parameters of the brake pads of freight cars under hazardous wear. Methodology. A set of operational and theoretical studies concerning the occurrence of hazardous wear, which changes the geometric parameters of the useful contact area of the brake pads of freight cars at different established gaps between the pad and the wheel, which significantly impairs the effectiveness of train braking. Using the collected statistical material, computer mathematical modeling of the upper hazardous wear at different gaps was performed and the negative factors affecting the brake system were identified. MathCAD and AutoCAD software was used. Findings. As a result of inspections of the mechanical part of the brakes, attention was paid to the abnormal wear of the brake pads of the freight cars, which is formed by the fact that the common gravity center of the pad and the shoe, placed on the pendular suspension, do not coincide with the center of the hole in brake beam king post with any pads. In order to investigate possible causes of abnormal wear of the brake pads, their real images and theoretical schemes are given, which allow to establish the causes of the formation of abnormal wear of the pads at different gaps between the pad and the wheel and to determine their change of geometrical parameters that affect the useful contact area. When comparing the results of calculations according to the coordinate method performed in the MathCAD software environment and the graphic method (in AutoCAD), for determining the geometric parameters of the formation of the upper hazardous pad wear, depending on the regulatory pad wear between the wheel and the brake pad, it is theoretically proved that the error between them does not exceed 5–7%. Originality. For the first time, the principles of the methodology for determining the geometric parameters of the useful contact area of the pads with the formation of upper hazardous wear, depending on the gap between the wheel and the brake shoe, were formulated using coordinate and graphical methods. Practical value. It is advisable to apply the results of the research obtained in the work in the design and technological departments and bureaus when designing both mechanical brake systems for the undercarriage of innovative cars and for improvement of the cars currently operated at the railways.

Can Cosmetics' Advertisements Be An Indicator of Different Perceptions of Beauty Amongst Countries?

Concepts of beauty are different amongst different cultures and civilizations. The objective of this study was to evaluate beauty perceptions through cosmetic advertisements in an effort to further appreciate beauty understanding amongst lay people in various parts of the world. To achieve these objectives, we reviewed cosmetics' advertisements to study whether the concept of beauty varies amongst different countries. We used the keywords "cosmetics" and "advertisements" in YouTube search engine in all existing languages in Google translator and came up with advertisements from 18 countries. The faces of the models were compared against Marquardt® beauty mask template in order to have a mean to objectively test symmetry with a mathematical computer model. The weak point of our study is that we can present no model photographs due to General Data Protection Regulation. Advertisements retrieved in total were 257. Characteristics with no statistically significant difference (SSD) amongst models in different parts of the world were: symmetry (p = 0.187), high cheek bones (p = 0.325), small noses (p = 0.72), thin jaws (p = 0.98), lush hair (p = 0.54), clean and smooth skin (p = 0.367), and white toothed smile (p = 0.235). Characteristics with SSD were: in Latin America, USA, and Australia tanned models and fuller lips were preferred (p < 0.001), whilst in Asia milky white skin models and small mouth were preferred. Age ratio (p = 0.022) was lower amongst models in Southeast Asia compared to American, European, Indian, Australian, and Arab models. Arab and Southeast Asia women had intense eyebrows (p < 0.001) and used artificial eyelashes. All the common characteristics noted by the two independent surgeons (GAS and LP) referred to symmetry, youthfulness, and health. Differences noticed reflected cultural influences in the perception of beauty. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Exergy and energy analysis of low GWP refrigerants in the perspective of replacement of HFC-134a in a home refrigerator

The present work focusses on comparison of several low Global warming potential (GWP) refrigerants in search of possible alternatives to a refrigerant HFC-134a of a home refrigerator without any modifications. A computational mathematical model is developed and thermodynamic analysis has been carried out to investigate the influence of Evaporator temperature on the performance characteristics like Volumetric Cooling Capacity (VCC), Compressor power consumption, COP, and Compressor discharge temperature at two different Condenser temperatures (25°C and 45°C). By exergy analysis Exergetic efficiency, Exergy destruction ratio, and Efficiency defect across different components of the Vapour compression refrigeration system are also evaluated. Comparison is made between different refrigerants mentioned above. Results obtained revealed that the refrigerants HFO- 1234yf and HFC-152a can be a good replacement of HFC-134a refrigerant without any modifications. Condenser and Liquid suction heat exchanger (LSHX) have the highest and the lowest Efficiency defect respectively, among all the system components of a home refrigerator.

Nonlinear Dynamics and the Synchronization of Neural Ensembles in the Shaping of Attention

A way of studying the synchronization of relaxation self-oscillations is considered. The technique is based on a modified axiomatic approach that uses the properties of uniform near-periodic functions. Five regimes of synchronizing neural ensembles of 100 peripheral neurons in the shaping of attention are studied. The adequacy of the mathematical computational model used to describe the process of shaping attention is discussed.

Автоматизація досліджень багатошарових систем

The article considers the issues of calculating and setting parameters of multilayer microbiological systems containing local concentrated discrete sources of temperature fields. As an object of research in the work, the considered multilayer, unlimited microbiological material subjected to local point thermal influence. The novelty of the author’s research is to take into account the specific features of the process of thermal action and the multilayer structure of microbiological material. The purpose of the research is to build physically justified computational mathematical models that describe the state of the research object, as well as to outline ways for the optimization process of a whole class of multilayer microbiological systems. The author has constructed a calculated mathematical model of the process of point thermal action on a multilayer unlimited microbiological material. It should be noted that a feature of the object of study is that its state is described by a boundary-value problem for a system of non-stationary, inhomogeneous differential heat equations (a system with distributed parameters). This specificity significantly complicates the process of constructing the appropriate mathematical models for optimizing multilayer microbiological systems, as well as their use to improve the quality of the biotechnological process of dividing (cutting, segmentation) microbiological material. In this regard, the author proposes to implement the procedure for solving a series of boundary value problems and ensuring an iterative process of searching for rational parameters of heat exposure on a specialized grid analog or hybrid model. This will allow at each iteration to significantly reduce the time it takes to solve a boundary value problem, which will make it possible to increase the accuracy of solving the entire problem of searching for parameters of the systems under consideration. Key words : mathematical models, optimization, boundary value problem, analog model, hybrid model

Simulation of Bioreactors for PHB Production from Natural Gas

Recently, many economic studies of poly(3-hydroxybutyrate) PHB production on an industrial scale, and the impact of replacing petrochemical polymers by PHB were carried out, clearly indicating that the most crucial factors to reduce the cost of producing biopolymers are allotted to the application of microbial production strains capable of high productivity in inexpensive carbon sources, high cell density cultivation methods, cheap yet effective methods for the extraction of PHB and other polyhydroxyalkanoates (PHAs), and gene transfer from bacteria to plants. We present current strategies to reduce the production price of biological PHA. Because an important part of the PHA production cost is related to the cost of carbon source, the article focuses on the use of natural gas as an inexpensive and readily available C1-carbon source. Since the first and foremost point in PHA production is biomass growth, we discuss different types of bioreactors to be potentially used for efficient biomass production from natural gas, which facilitates the subsequent selection of the ideal bioreactor for PHA production from this substrate. Nowadays, process simulation software can be used as a powerful tool for analysis, optimization, design, and scale up of bioprocesses. Controlling the process design by in silico simulations instead of performing an excessive number of lab-scale experiments to optimize various factors to save in time, material and equipment. Simulation of PHA production processes to find the optimal conditions can play a decisive role in increasing the production efficiency. Computational fluid dynamics and mathematical modeling helps us to achieve a better understanding of the role of different nutrients, flow parameters of gaseous substrates, efficient feeding strategies, etc. This finding leads to higher productivity by prediction of parameters e.g. nutrient supply and biomass concentration time profile and their respective yields.

Studying Generation Modes of Linearized Artificial Neurons Based on FPGA Architecture Hardware Implementation

This paper describes the development of embedded software for the implementation and testing of the artificial multistable neuron model’s basic behavior with the help of the hardware architecture of programmable logic integrated circuits (FPGA). The real behavior and function of the biological neuron with linearized activation characteristics are investigated and implemented in the programming language VHD. The base model is a three-stable neuron with three asymmetric dendrites. To develop a hardware model, a computational mathematical model of a neuron is used, based on which a corresponding discrete model is synthesized. The model consists of the following modules: an input block, a timer, a clock generator, a threshold element, and an output signal generator. It is shown that the implemented system allows synthesizing a neural model with a predetermined number of stable discrete states, with the neuron changing its stable state depending on the input vector. Each stable state corresponds to the output function of the neuron. The developed model of artificial neurons was implemented on the DIGILENT BASYS II SPARTAN-3E XC3S100E FPGA kit in the WebPACKTM ISE 13.3 environment. Resulting neuron output generation modes relation from input sequences and structure parameters were studied. The results of the work allow investigating high-speed neural networks with a dynamic structure using FPGA, which can be used for a wide range of modern tasks such as recognition, classification of patterns and development of elements of artificial intelligence.

Software Program for Two Levers Damper Configurations Used for Anti-Seismic Protection of the Buildings during Seism

For a building equipped with anti-seismic devices, the value of the damping force of the dampers positioned at the superstructure is very important for an efficient anti-seismic damping and therefore an optimization of the seismic protection system with dampers is required. There are several configurations for placing the dampers that amplify the displacement and the damper axial force. This paper presents a computational mathematical model made for determining the coefficients of displacement multiplication and the damping force multiplication for two special positioning configurations of the antiseismic dampers using levers. Based on this model, a software program was created that allows to choose the geometrical parameters of two configurations of dampers placement having as criterion of choice the value of the amplification coefficient of the dampers displacement or the damper axial force.

Rumor model on homogeneous social network incorporating delay in expert intervention and government action

Rumors are spreading all over the network drastically, affecting millions of people in a minuscule instance. This malicious news can be a cause of panic, social unrest, political imbalance, and slow economic growth of the country. Epidemiological modeling is a valuable tool to describe not only the dynamics of rumor on a social network but also analyzing the effect of various control strategies for handling emergencies. The time delay is viewed as a latent period and immune period in epidemics. Similarly, time delay exists in rumor spreading on the social network not only to influence thinkers by rumor adopters but also in expert intervention and government policy. On the basis of these premises, we propose a computational mathematical model of malicious news dynamics on a homogeneous social network and demonstrate the effect of delay in expert intervention and government action. Here, we observe that it is difficult to judge the opinion of the social network user about any particular event, if experts take more time to respond and are not continuously active to make aware of the newcomers. Also, social network data become unpredictable, so this work can be helpful for the information security of social network data.The condition of existence and stability of steady states are studied. We also evaluate the Hopf bifurcation condition and calculate the critical value of delay in expert intervention. Moreover, we recognize the most sensitive parameter to the system and numerically simulate the model with some useful parameter sets to justify the theoretical findings.

Optimisation of surrounding layout of enterprise building using an improved genetic algorithm

In order to achieve the optimal design of environment and overall layout of enterprise building, the improved genetic algorithm is applied in it. First, the relationship between the environment and layout of enterprise building. Secondly, the optimal model of environment and overall layout of enterprise building is constructed, and the objective function and boundary conditions are confirmed. Thirdly, the procedure of improved genetic algorithm is designed, and the mathematical models of cross operation and niche computation are established. Finally, the simulation analysis of environment and overall layout of enterprise building is carried out, and simulation results show that the improved genetic algorithm can obtain the better environment and overall plan of enterprise building.

Modelling the Process of Processing Ash and Slag Wastes of TPP by Means of Consistent Application of CAE- and CAD- systems

The article considers the possibility of joint application of mathematical processing and computer 3D modeling of the technological process line for processing ash and slag waste from thermal power plants (TPP). The authors suggest considering an approach to the design of the ash and slag waste processing site by mathematical processing and 3D computer modeling. The mathematical processing with the help of E- network device and the creation of a 3D model allows to plan the site for processing ash and slag waste, select the appropriate technology and thereby ensure the environmental effect of both existing and projected power plants. The authors present the results of processing the technological process of recycling ash and slag wastes of TPP in terms of E-networks using mathematical processing in the Simulink application, which displays the device model from the standard blocks available in the program and performs the necessary calculations. 3D models of individual equipment units selected on the basis of mathematical processing calculations in the Simulink application, were created using computer 3D modeling in a graphical editor. A 3D visualization of the technological section of ash and slag waste processing was performed, which allows to clearly show the planned section at the design stage, which, if necessary, will allow to easily make changes to the project.

Information technologies for landslides and mudflows research

This article presents the results of research using computer technology and mathematical modeling in relation to hydrodynamic processes that determine such natural disasters as landslides and mudflows common in the territory of the Kyrgyz Republic. A specialized website is proposed, which contains the results of scientific research on natural and man-made disasters and exogenous geological processes (EGP). The following systems were used as the main database management systems (DBMS): MS Access, My SQL and PostgreSQL. Thus, the main means of developing computer programs and computational procedures are Delphi, Python, Visual Basic, Java and JavaScript. Web technologies and the following software tools were used to design and create the site: Python, JavaScript, PhP and HTML. Modern level of scientific research presumes and obliges development and using of new information technologies. In this regard there was defined a problem on mathematical modelling and information technologies using for research and forecasting of EGP on the territory of Kyrgyzstan. There are proposed hydrodynamic models and numerical methods of their solution. Information system is developed for landslides, mudflows, and other EGP types, typical for Kyrgyzstan.

Применение информационных технологий для оптимизации лечения мочекаменной болезни

Urolithiasis is one of the most common pathologies in urological practice. To ensure a personalized approach in the treatment of urolithiasis by taking into account the specific characteristics of each individual patient and various alternative methods of treatment, mathematical models and algorithms are increasingly being used that significantly improve the quality of medical care. One of the most promising directions in the field of creating mathematical computer models is the development and implementation into daily practice predictive models based on the so-called artificial neural networks. They combine the complex pro-perties of neurons of the human brain to analyze and process the information received. An analysis of domestic and foreign literature has been carried out sho-wed that there is an active development of computer technologies using neural network models that allow rationalizing the tactics of treating patients, in particular with urolithiasis. In order to personalize the approach to the management of patients with urolithiasis and increase the reliability of predicting treatment results on the basis of the urological department of the State Clinical Hospital of S.P. Botkin within the framework of the research work of the Department of Urology and Surgical Andrology of Medical Academy of Continuous Professional Education along with the National Research University of Electronic and Technology “MIET” it has been planned to develop a program based on neural network modeling. This program will allow to standardize the choice of the method of treatment of ureteral stones and will help urologists make difficult decisions in non-standard situations, which will lead to an increase in the efficiency and quality of medical care.

Robust Calibration of High Dimension Nonlinear Dynamical Models for Omics Data: An Application in Cancer Systems Biology

In computational mathematical modeling of biological systems, most model parameters, such as initial conditions, kinetics, and scale factors, are usually unknown because they cannot be directly measured. Therefore, key issues in system identification of nonlinear systems are model calibration and identifiability analysis. Currently, existing methodologies for parameter estimation are divided in two classes: frequentist and Bayesian methods. The first optimize a cost function, while the second estimate the posterior distribution of parameters through different sampling techniques. However, when dealing with high-dimensional models, these methodologies suffer from an increasing computational cost due to the important volume of -omic data necessary to carry out reliable and robust solutions. Here, we present an innovative Bayesian method, called conditional robust calibration (CRC), for model calibration and identifiability analysis. The algorithm is an iterative procedure based on a uniform and joint perturbation of the parameter space. At each step the algorithm returns the probability density functions of all parameters that progressively shrink toward specific points in the parameter space. These distributions are estimated on parameter samples that guarantee a certain level of agreement between each observable and the corresponding in silico measure. We apply CRC to a nonlinear high-dimensional ordinary differential equations model representing the signaling pathway of p38MAPK in multiple myeloma. The available data set consists of time courses of proteomic cancerous data. We test CRC performances in comparison with profile-likelihood and approximate Bayesian computation sequential Monte Carlo. We obtain a more precise and robust solution with a reduced computational cost.

The stability of the wall of the main beam of the movable bridge (application of SP method)

The objects of the article are: analyze the work of the main beams of the movable span of the drop-down system near the axis of rotation; analyze the stress-strain state of the main beams of the movable span of the drop-down system near the axis of rotation; analyze the acceptability of the normative methodology (SP) for calculating the stability of the wall of a continuous steel beam during the design and calculation of movable bridge of the drop-down system. A computational-mathematical model of the movable span of the drop-down system is developed in a modern computational software package based on the finite element method. The main disadvantages of the normative methodology (SP) for calculating the wall stability of a continuous steel beam which used in design and calculation of movable bridge of a drop-down system are presented.

Electrorotation of Arbitrarily Shaped Micro-Objects: Modeling and Experiments

In this article, we study the electrorotational behavior of nonspherical micro-objects. We extend a control-oriented model of general dielectrophoresis to incorporate also the hydrodynamics so that we can predict the motion of nonspherical micro-objects in fluidic environments. Such a mathematical (computational) model enables model-based feedback control of a position and orientation of particles by real-time (online) computation of voltages applied to the electrodes. We use the measured data from experiments with electrorotation of an artificial micro-object having a Tetris-like shape to evaluate the performance of the proposed model. We also demonstrate the qualitative difference in behavior from the commonly performed electrorotation of a sphere advocating the necessity for model-based control. Further analysis of the simulation results for other than the experimentally explored scenarios provides additional useful insight into the electrorotational behavior of nonspherical objects.

О ПРИМЕНИМОСТИ ФАЗОВОГО МЕТОДА СКАНИРОВАНИЯ В АНТЕННЫХ РЕШЕТКАХ ИМПУЛЬСНЫХ ЛЧМ-РАДАРОВ

О ПРИМЕНИМОСТИ ФАЗОВОГО МЕТОДА СКАНИРОВАНИЯ В АНТЕННЫХ РЕШЕТКАХ ИМПУЛЬСНЫХ ЛЧМ-РАДАРОВ