mathematical modeling

MATHEMATICAL FORECASTING OF SPATIO-TEMPORAL DYNAMICS OF HYDROECOLOGICAL PARAMETERS OF RIVER ECOSYSTEMS USING INTEGRALLY-MODIFIED STREETER-PHELPS MODEL

This study presents a comprehensive mathematical forecasting approach for hydroecological parameters in small urban river systems using an integrally-modified Streeter-Phelps model. The research focuses on the Kamyanka River, a small tributary within Zhytomyr city, Ukraine, which experiences significant anthropogenic influence from urban development. The modified model incorporates advanced computational algorithms implemented in Python programming environment to predict dissolved oxygen concentration and biochemical oxygen demand dynamics over a 25-year period (2020-2045).

Mathematical modeling of multi-label classification of job descriptions using transformer-based neural networks

This article presents the mathematical modeling of the multi-label classification task of job description texts aimed at the automatic detection of working conditions and social benefits, which can enhance communication efficiency between employers and job seekers.  The proposed approach is based on the use of the transformer-based BERT neural network, pre-trained on a multilingual corpus.  The dataset was constructed by collecting job postings from the three largest Ukrainian job search platforms: Work.ua, Robota.ua, and Jooble.org.  The collected texts were augmented

Drying of cappilary-porous materials in an external constant electric field

In the article, the mathematical model for the drying process of a porous layer subjected to an external electric field is developed considering the coupled effects of heat, mass, and charge transport.  A system of algebraic equations is obtained to describe the drying dynamics, incorporating key physical parameters such as boundary layer thickness, temperature, and electric field intensity.  The model is validated against experimental data, demonstrating its accuracy in predicting moisture distribution over time in a porous materials under the action of constant electr

Mathematical modeling of the extraction process of target components from yeast biomass

A generalized mathematical model of the process of extraction of target components from yeast biomass (carbohydrates, lipids and ribonucleic acids)has been developed on the basis of experimental studies.  It is substantiated that the theoretical provisions are satisfactorily consistent with the experimental results of the research.  The obtained model allows to describe with sufficient accuracy the kinetics of extraction of carbohydrates, lipids and ribonucleic acids from yeast biomass, to determine the yield of the extract and to predict the optimal time of extraction

Modeling the dynamics of a capsule-type locomotion system actuated by an imbalanced rotor under the action of dry anisotropic friction

Mobile robotic systems with vibratory drives are becoming increasingly popular in various fields of industry and medicine.  This article is dedicated to the study of the dynamic behavior of a mobile capsule-type robot equipped with an imbalanced vibration exciter.  The research methodology involves constructing a simplified dynamic diagram of the robot's mechanical system, using Lagrange's equations of the second kind to describe its motion, and solving the obtained system of differential equations using numerical methods integrated into the Wolfram Mathematica software

DESIGN OF A VIBRATING MACHINE FOR DRY CLEANING OF ROOT VEGETABLES USING NONLINEAR MATHEMATICAL AND THREE-DIMENSIONAL MODELING

The design of a highly efficient vibrating machine for dry cleaning root vegetables of various types, shapes, and sizes has been developed. First, a schematic diagram of the machine was built, containing all the future machine's main components. A nonlinear mathematical model was constructed to describe its dynamics during its operation to determine the future machine's optimal geometric, kinematic, and power parameters. The mathematical model is based on the apparatus of asymptotic methods of nonlinear mechanics and Lagrange's equations.

An Influence of the Time and Spatial Harmonics on an Electromagnetic Torque of a Symmetrical Six-Phase Induction Machine With a Six-Step Inverter Supply Under Open Phase Circuit Fault

Six-phase induction machines offer several advantages over traditional three-phase machines, including higher levels of electromechanical compatibility with loads, energy efficiency, and fault tolerance.

This article presents an analysis of the impact of harmonics in the winding distribution function in the stator slots and the harmonics of the machine’s supply on its electromechanical compatibility with the load during a single-phase failure.

Energy-efficient Control of Electric Vehicle Heating, Ventilation, and Air Conditioning System – Performance Optimization and Energy Consumption Reduction

The article addresses the challenge of improving the energy efficiency of the heating, ventilation, and air conditioning (HVAC) system in electric vehicles. Due to the absence of an internal combustion engine in electric vehicles, there is no additional heat source, meaning that HVAC systems consume a significant portion of the battery energy, thereby reducing the vehicle’s range. The aim of this study is to develop an energy-efficient control algorithm for the HVAC system that minimizes energy consumption while maintaining adequate comfort levels for passengers.

Modeling the Block Formation Process in Blockchain and Its Impact on Scalability

The article investigates the process of block formation in blockchain networks and the impact of node network architecture and consensus algorithms on their scalability and performance. Analysis of blockchain system scalability is important due to problems that arise when network load increases, particularly the increase in the number of block forks and transaction confirmation times. The research focuses on studying the impact of network delays and the choice of consensus algorithm on the performance and scalability of blockchain networks.

Mathematical modeling of solid municipal waste landfill surface settlement with regard to organic component biodegradation

Landfilling of municipal solid waste generates a number of problems.  This article focuses on one of them – the settling of the landfill surface due to organic residue biodegradation.