Online Library. Theme: Physical and mathematical sciences (p.4)
Found: 181
Found: 181
| Title: | Invariant Almost Contact Structures and Connections on the Lobachevsky Space |
| Author: | Surina Olga |
| Type: | Article |
| Kind: | Electronic edition |
| Publication date: | 2023 |
| Publishing house: | Pleiades Publishing, USA |
| Title: | Inverse Problem for the Integral Dynamic Models with Discontinuous Kernels. |
| Author: | Тында Александр Николаевич |
| Type: | Article |
| Kind: | Electronic copy |
| Publication date: | 2022 |
| Publishing house: | Multidisciplinary Digital Publishing Institute (MDPI) |
| Title: | Inverse Problem of Diffraction by an Inhomogeneous Solid with a Piecewise H¨older Refractive Index |
| Author: | Цупак Алексей Александрович Медведик Михаил Юрьевич |
| Type: | Article |
| Kind: | Electronic edition |
| Publication date: | 2018 |
| Publishing house: | arXiv.org |
| Title: | Inverse vector problem of diffraction by inhomogeneous body with a piecewise smooth permittivity |
| Author: | Цупак Алексей Александрович Медведик Михаил Юрьевич |
| Type: | Article |
| Kind: | Electronic copy |
| Publication date: | 2023 |
| Publishing house: | DE GRUYTER POLAND SP ZOO, BOGUMILA ZUGA 32A STR., 01-811 WARSAW, POLAND |
| Title: | Investigation of Acoustic Wave Scattering from a System of Soft Screens by the Method of Integral Equations |
| Author: | Нестеров Владислав Олегович Цупак Алексей Александрович |
| Type: | Article |
| Kind: | Electronic copy |
| Publication date: | 2024 |
| Publishing house: | Springer Nature Switzerland |
| Title: | INVESTIGATION OF DIFFERENCE METHODS FOR SOLVING STEFAN'S PROBLEM OF FREEZING WET SOIL |
| Author: | Кудряшова Наталья Юрьевна |
| Type: | Article |
| Kind: | Electronic copy |
| Publication date: | 2024 |
| Publishing house: | Издательство Южно-Уральского государственного университета |
| Title: | Investigation of electromagnetic wave diffraction from an inhomogeneous partially shielded solid |
| Author: | Цупак Алексей Александрович |
| Type: | Article |
| Kind: | Electronic copy |
| Publication date: | 2018 |
| Publishing house: | Taylor & Francis, UK |
| Title: | Kinetic coefficients of semiconductor superlattices in high-frequency electromagnetic fields |
| Author: | Vladimir Dmitrievich Mikhail Borisovich |
| Type: | Article |
| Kind: | Electronic copy |
| Publication date: | 2017 |
| Publishing house: | Университет ИТМО |
| Title: | Leaky waves in a nonlinear metamaterial rod |
| Author: | Смолькин Евгений Юрьевич Снегур Максим Олегович |
| Type: | Article |
| Kind: | Electronic edition |
| Annotation: | Journal of Electromagnetic Waves and Applications |
| Publication date: | 2020 |
| Publishing house: | Taylor & Francis, UK |
| Title: | Learning Radial Basis Function Networks with the Trust Region Method for Boundary Problems |
| Author: | Горбаченко Владимир Иванович |
| Type: | Article |
| Kind: | Electronic copy |
| Annotation: | We consider the solution of boundary value problems of mathematical physics with neural networks of a special form, namely radial basis function networks. This approach does not require one to construct a difference grid and allows to obtain an approximate analytic solution at an arbitrary point of the solution domain. We analyze learning algorithms for such networks. We propose an algorithm for learning neural networks based on the method of trust region. The algorithm allows to significantly reduce the learning time of the network. |
| Publication date: | 2018 |
| Publishing house: | Springer |
| Title: | Learning Radial Basis Functions Networks in Solving Boundary Value Problems |
| Author: | Горбаченко Владимир Иванович |
| Type: | Article |
| Kind: | Electronic edition |
| Annotation: | The authors considered the solution of boundary problems, arising from objects modeling with distributed parameters, of radial basis functions networks. The gradient algorithms analysis for learning radial basis functions networks when solving boundary value problems is carried out. The widely used the first order method-the gradient method descent does not provide high learning rate and the solution accuracy. The fastest of the second order method - the method of trust regions is very complicated. Developed implementations of the first order method-the accelerated Nesterov gradient and the second order method Levenberg-Marquardt for learning radial basic functions networks in solving boundary value problems. A comparison is made of the Levenberg- Marquardt methods and trust regions for learning radial basis functions networks. The results are presented of solving model problem using the developed methods. The Levenberg-Marquardt method, with a simpler implementation, showed the results compared with the fastest method of the second order - the method of trust regions. |
| Publication date: | 2019 |
| Publishing house: | Proceedings - 2019 International Russian Automation Conference |
| Title: | Machine Learning-Driven Compact Hexa-Band THz Metamaterial Absorber |
| Author: | Кузнецова Ольга Юрьевна Razuvaeva Tatiana |
| Type: | Article |
| Kind: | Electronic copy |
| Annotation: | This work presents a metamaterial absorber designed for terahertz applications, featuring a dual-elliptical split-ring resonator geometry enclosed within a square frame. The structure is made on a polyimide substrate with metallic layers and exhibits six distinct absorption peaks at 3.45, 5.15, 7.01, 8.97, 10.50, and 10.89 terahertz, with corresponding absorptivity values of 94.2%, 94.2%, 98.06%, 99.45%, 85.87%, and 97.7%, respectively. At its lowest operating frequency, the proposed absorber is ultra-thin (0.068λ) and electrically compact (0.285λ), making it suitable for potential applications in stealth and sensing technologies. To improve multi-band absorption, machine learning models including Extra Tree, XGBoost, and an ensemble approach were employed for optimization. The ensemble model, is evaluated for enhancing absorber efficiency, with model performance validated through 10-fold cross-validation. Model accuracy was assessed using R-squared, Mean Absolute Error, and Root Mean Squared Error metrics. Ensemble approach was applied, with the ensemble achieving the highest R-squared value of 0.9944 for predicting the effects of geometric parameters. |
| Publication date: | 2026 |
| Publishing house: | IEEE |
| Title: | Macroscopic effects of dissipative tunneling in semiconductive InAs/GaAs quantum dots |
| Author: | Vladimir Dmitrievich Mikhail Borisovich Зайцев Роман Владимирович Семенов Иван Михайлович |
| Type: | Article |
| Kind: | Electronic copy |
| Annotation: | Temperature effects of lD-dissipative tunneling for the two-well oscillator potential model within the strong dissipation limit for the case of semiconductor QDs of InAs, were analyzed using a combined atomic force and scanning tunneling microscope. The effect of thermal control for the amplitude of single peaks on the field dependence of the one-dimensional dissipative tunneling probability in the model under consideration was theoretically revealed. A qualitative comparison of the calculated field dependences of the lD-dissipative tunneling probability at a finite temperature within a strong coupling limit (with allowance for the influence of two local phonon modes) with experimental tunnel CVC was obtained. A fairly convincing agreement of theoretical and experimental curves was demonstrated. It is shown that in addition to temperature and external electric field, another important controlling parameter of dissipative tunneling is the type of thermostat matrix in which QDs have been synthesized, taking into account the number of local phonon modes involved in the tunneling process. © 2019 Published under licence by IOP Publishing Ltd. |
| Publication date: | 2019 |
| Publishing house: | IOP Publishing |
| Title: | Mathematical Modeling on a Physics-Informed Radial Basis Function Network |
| Author: | Горбаченко Владимир Иванович Стенькин Дмитрий Александрович |
| Type: | Article |
| Kind: | Electronic copy |
| Annotation: | The article is devoted to approximate methods for solving differential equations. An approach based on neural networks with radial basis functions is presented. Neural network training algorithms adapted to radial basis function networks are proposed, in particular adaptations of the Nesterov and Levenberg-Marquardt algorithms. The effectiveness of the proposed algorithms is demonstrated for solving model problems of function approximation, differential equations, direct and inverse boundary value problems, and modeling processes in piecewise homogeneous media. |
| Publication date: | 2024 |
| Publishing house: | MDPI |
| Title: | Mathematical Theory of Normal Waves in an Anisotropic Rod |
| Author: | Смолькин Евгений Юрьевич Снегур Максим Олегович |
| Type: | Article |
| Kind: | Electronic edition |
| Publication date: | 2020 |
| Publishing house: | Pleiades Publishing |
| Title: | Mathematical theory of normal waves in an open metal-dielectric regular waveguide of arbitrary cross section |
| Author: | Смолькин Евгений Юрьевич |
| Type: | Article |
| Kind: | Electronic edition |
| Publication date: | 2020 |
| Publishing house: | Springer |
| Title: | Mathematical Theory of Surface Waves in a Lossy Inhomogeneous Dielectric Waveguide of Arbitrary Cross Section |
| Author: | Мартынова Валерия Юрьевна |
| Type: | Article |
| Kind: | Electronic copy |
| Annotation: | https://link.springer.com/article/10.1134/S1995080221060263 |
| Publication date: | 2021 |
| Publishing house: | Lobachevskii Journal of Mathematics |
| Title: | Mathematical theory of transverse-magnetic guided waves in a plane waveguide filled with nonhomogeneous nonlinear medium |
| Author: | Валовик Дмитрий Викторович Тихов Станислав Вячеславович |
| Type: | Article |
| Kind: | Electronic copy |
| Publication date: | 2025 |
| Publishing house: | IOP Publishing |
| Title: | Maxwell's equations with arbitrary self-action nonlinearity in a waveguiding theory: Guided modes and asymptotic of eigenvalues |
| Author: | Валовик Дмитрий Викторович Тихов Станислав Вячеславович |
| Type: | Article |
| Kind: | Electronic copy |
| Publication date: | 2019 |
| Publishing house: | Elsevier |
| Title: | Measuring a Near Electromagnetic Field and Restoring the Parameters of Inhomogeneities in a Dielectric Body |
| Author: | Лапич Андрей Олегович |
| Type: | Article |
| Kind: | Electronic copy |
| Publication date: | 2025 |
| Publishing house: | Pleiades Publishing |