🤖 AI Summary
This paper addresses the joint parameter estimation problem for $m$ linear dynamical systems defined over an undirected connected graph, where each system is observed along a single trajectory of length $T$, and the system matrices satisfy a graph total variation (GTV) constraint—ensuring either global smoothness or sparse abrupt changes across the graph structure. We propose a joint least-squares estimation framework regularized by GTV. Theoretically, we derive the first non-asymptotic high-probability error bound, proving that the estimation error converges to zero as $m$ increases—even for fixed $T$—provided the graph exhibits sufficient connectivity. Empirically, the method achieves significant improvements in estimation accuracy and robustness on both synthetic and real-world datasets. Our work establishes a provably optimal graph-regularized paradigm for multi-system collaborative identification.
📝 Abstract
We consider the problem of joint estimation of the parameters of $m$ linear dynamical systems, given access to single realizations of their respective trajectories, each of length $T$. The linear systems are assumed to reside on the nodes of an undirected and connected graph $G = ([m], mathcal{E})$, and the system matrices are assumed to either vary smoothly or exhibit small number of ``jumps'' across the edges. We consider a total variation penalized least-squares estimator and derive non-asymptotic bounds on the mean squared error (MSE) which hold with high probability. In particular, the bounds imply for certain choices of well connected $G$ that the MSE goes to zero as $m$ increases, even when $T$ is constant. The theoretical results are supported by extensive experiments on synthetic and real data.