Tootfinder

Leveraging the Doppler Effect for Channel Charting
Florian Euchner, Phillip Stephan, Stephan ten Brink
https://arxiv.org/abs/2404.09620 https://

Leveraging the Doppler Effect for Channel Charting
Channel Charting is a dimensionality reduction technique that reconstructs a map of the radio environment from similarity relationships found in channel state information. Distances in the channel chart are often computed based on some dissimilarity metric, which can be derived from angular-domain information, channel impulse responses, measured phase differences or simply timestamps. Using such information implicitly makes strong assumptions about the level of phase and time synchronization be…

Local control on quaternionic Heisenberg group of dimension $7$
Jan Eisner, Lenka Zalabov\'a
https://arxiv.org/abs/2404.08953 https://

Local control on quaternionic Heisenberg group of dimension $7$
We describe the quaternionic Heisenberg group in the dimension $7$ as a matrix group. We study the local control of a compatible left-invariant control system. We describe the impact of symmetries of the corresponding sub-Riemannian structure on the optimality of geodesics.

On irreducibility of eccentricity matrix of graphs and construction of $\epsilon-$equienergetic graphs
Anjitha Ashokan, Chithra A V
https://arxiv.org/abs/2404.19537

On irreducibility of eccentricity matrix of graphs and construction of $ε-$equienergetic graphs
The eccentricity matrix $ε(G)$, of a connected graph $G$ is obtained by retaining the maximum distance from each row and column of the distance matrix of $G$ and the other entries are assigned with 0. In this paper, we discuss the eccentricity spectrum of subdivision vertex (edge) join of regular graphs. Also, we obtain new families of graphs having irreducible or reducible eccentricity matrix. Furthermore, we use these results to construct infinitely many $ε-$cospectral graph pairs as well a…