Tootfinder

PINN and GNN-based RF Map Construction for Wireless Communication Systems
Lizhou Liu, Xiaohui Chen, Zihan Tang, Mengyao Ma, Wenyi Zhang
https://arxiv.org/abs/2507.22513 https://…

PINN and GNN-based RF Map Construction for Wireless Communication Systems
Radio frequency (RF) map is a promising technique for capturing the characteristics of multipath signal propagation, offering critical support for channel modeling, coverage analysis, and beamforming in wireless communication networks. This paper proposes a novel RF map construction method based on a combination of physics-informed neural network (PINN) and graph neural network (GNN). The PINN incorporates physical constraints derived from electromagnetic propagation laws to guide the learning …

Multi-timescale frequency-phase matching for high-yield nonlinear photonics
Mahmoud Jalali Mehrabad, Lida Xu, Gregory Moille, Christopher J. Flower, Supratik Sarkar, Apurva Padhye, Shao-Chien Ou, Daniel G. Suarez-Forero, Mahdi Ghafariasl, Yanne Chembo, Kartik Srinivasan, Mohammad Hafezi
https://arxiv.org/abs/2506.15016

Multi-timescale frequency-phase matching for high-yield nonlinear photonics
Integrated nonlinear photonic technologies, even with state-of-the-art fabrication with only a few nanometer geometry variations, face significant challenges in achieving wafer-scale yield of functional devices. A core limitation lies in the fundamental constraints of energy and momentum conservation laws. Imposed by these laws, nonlinear processes are subject to stringent frequency and phase matching (FPM) conditions that cannot be satisfied across a full wafer without requiring a combination …

Stability of the Active Flux Method in the Framework of Summation-by-Parts Operators
Wasilij Barsukow, Christian Klingenberg, Lisa Lechner, Jan Nordstr\"om, Sigrun Ortleb, Hendrik Ranocha
https://arxiv.org/abs/2507.11068

Stability of the Active Flux Method in the Framework of Summation-by-Parts Operators
The Active Flux method is a numerical method for conservation laws using a combination of cell averages and point values, based on ideas from finite volumes and finite differences. This unusual mix has been shown to work well in many situations. We expand the theoretical justifications of the Active Flux method by analyzing it from the point of view of summation-by-parts (SBP) operators, which are routinely used to analyze finite difference, finite volume, and finite element schemes. We show th…