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We present IRIS, a new generic three-dimensional (3D) spectral radiative transfer code that generates synthetic spectra, or images. It can be used as a diagnostic tool for comparison with astrophysical observations or laboratory…

Instrumentation and Methods for Astrophysics · Physics 2015-06-12 L. Ibgui , I. Hubeny , T. Lanz , C. Stehlé

In this paper, we propose a novel integrated sensing and communication (ISAC) transmission framework based on the spatially-spread orthogonal time frequency space (SS-OTFS) modulation by considering the fact that communication channel…

Information Theory · Computer Science 2021-09-02 Shuangyang Li , Weijie Yuan , Chang Liu , Zhiqiang Wei , Jinhong Yuan , Baoming Bai , Derrick Wing Kwan Ng

Frequency domain super-heterodyne laser light scattering is utilized in a low angle integral measurement configuration to determine flow and diffusion in charged sphere suspensions showing moderate to strong multiple scattering. We…

An implicit method for radiative transfer in SPH is described. The diffusion approximation is used, and the hydrodynamic calculations are performed by a fully three--dimensional SPH code. Instead of the energy equation of state for an ideal…

Astrophysics · Physics 2009-11-11 Serge Viau , Pierre Bastien , Seung-Hoon Cha

This paper is concerned with the inverse problem to recover a compactly supported Schr{\"o}dinger potential given the differential scattering cross section, i.e. the modulus, but not the phase of the scattering amplitude. To compensate for…

Analysis of PDEs · Mathematics 2018-12-26 Alexey Agaltsov , Thorsten Hohage , Roman Novikov

We investigate transmission optimization for intelligent reflecting surface (IRS) assisted multi-antenna systems from the physical-layer security perspective. The design goal is to maximize the system secrecy rate subject to the source…

Information Theory · Computer Science 2020-05-12 Hong Shen , Wei Xu , Shulei Gong , Zhenyao He , Chunming Zhao

Near-field integrated sensing and communication (ISAC) leverages distance-dependent channel variations for joint distance and angle estimation. However, full-digital architectures have prohibitive hardware costs, making hybrid…

Information Theory · Computer Science 2025-12-05 Jiasi Zhou , Chintha Tellambura , Geoffrey Ye Li

This paper considers a time-fractional diffusion-wave equation with a high-contrast heterogeneous diffusion coefficient. A numerical solution to this problem can present great computational challenges due to its multiscale nature.…

Numerical Analysis · Mathematics 2025-02-14 Huiran Bai , Dmitry Ammosov , Yin Yang , Wei Xie , Mohammed Al Kobaisi

A nonlinear Poisson--Boltzmann equation with transmission boundary conditions at the interface between two materials is investigated. The model describes the electrostatic potential generated by a vector of ion concentrations in a periodic…

Analysis of PDEs · Mathematics 2018-10-22 Klemens Fellner , Victor Kovtunenko

The resonant absorption of light by an ensemble of absorbers decreases when the resonance is inhomogeneously broadened, as only a fraction of the ensemble contributes to the absorption at any given optical frequency. Recovering the lost…

Quantum Physics · Physics 2019-11-22 Ohr Lahad , Ran Finkelstein , Omri Davidson , Ohad Michel , Eilon Poem , Ofer Firstenberg

Direct numerical simulation of diffusion through heterogeneous media can be difficult due to the computational cost of resolving fine-scale heterogeneities. One method to overcome this difficulty is to homogenize the model by replacing the…

Numerical Analysis · Mathematics 2020-11-24 Nathan G. March , Elliot J. Carr , Ian W. Turner

Radiative transfer equilibrium models of nearby interstellar matter (ISM) yield the boundary conditions of the heliosphere when constrained with observations of ISM inside and outside of the heliosphere. Filtration factors for interstellar…

Astrophysics · Physics 2015-06-24 Priscilla C. Frisch

The integrating sphere (IS) is an indispensable tool for measuring transmission and scattering of materials and their colorimetry, as well as other photometric tasks. The accuracy of its data depends critically on port sizes used for…

Optics · Physics 2023-09-28 A. M. Bratkovsky

This paper proposes a novel reaction-diffusion system approximation tailored for singular diffusion problems, typified by the fast diffusion equation. While such approximation methods have been successfully applied to degenerate parabolic…

Analysis of PDEs · Mathematics 2026-04-01 Hideki Murakawa , Florian Salin

The standard formula, due to Spiegel, for the smoothing of temperature fluctuations by radiative transfer is unstable in relativity. This is due to the fact that Spiegel neglected the transit time of light, thereby allowing the transport…

Nuclear Theory · Physics 2025-05-09 Lorenzo Gavassino

We present a new approach to three-dimensional electromagnetic scattering problems via fast isogeometric boundary element methods. Starting with an investigation of the theoretical setting around the electric field integral equation within…

Numerical Analysis · Mathematics 2019-06-28 Jürgen Dölz , Stefan Kurz , Sebastian Schöps , Felix Wolf

Radiative transfer simulations are now at the forefront of numerical astrophysics. They are becoming crucial for an increasing number of astrophysical and cosmological problems; at the same time their computational cost has come to the…

In this paper, secure wireless information and power transfer with intelligent reflecting surface (IRS) is proposed for a multiple-input single-output (MISO) system. Under the secrecy rate (SR) and the reflecting phase shifts of IRS…

Signal Processing · Electrical Eng. & Systems 2019-11-05 Weiping Shi , Xiaobo Zhou , Linqiong Jia , Yongpeng Wu , Feng Shu , Jiangzhou Wang

Self-diffusion of a sphere in a network of rods is analyzed theoretically. Hydrodynamic interactions are taken into account according to the model of Dhont et al., under the assumption that $\ka << 1$ and $\bar{a}/L<<1$, where $1/\kappa$ is…

Soft Condensed Matter · Physics 2015-05-13 Bogdan Cichocki , Maria L. Ekiel-Jezewska

We study the singular limit of a spatially inhomogeneous and anisotropic reaction-diffusion equation. We use a Finsler metric related to the anisotropic diffusion term and work in relative geometry. We prove a weak comparison principle and…

Analysis of PDEs · Mathematics 2009-06-09 Matthieu Alfaro , Harald Garcke , Danielle Hilhorst , Hiroshi Matano , Reiner Schatzle