no code implementations • 15 Apr 2024 • Krzysztof Kowalczyk, Paweł Wachel, Cristian R. Rojas
This paper addresses a kernel-based learning problem for a network of agents locally observing a latent multidimensional, nonlinear phenomenon in a noisy environment.
no code implementations • 13 Apr 2024 • Rodrigo A. González, Siqi Pan, Cristian R. Rojas, James S. Welsh
In this paper, we address the consistency of the simplified refined instrumental variable method for continuous-time systems (SRIVC) and its closed-loop variant CLSRIVC when they are applied on data that is generated from a feedback loop.
no code implementations • 13 Apr 2024 • Rodrigo A. González, Koen Classens, Cristian R. Rojas, James S. Welsh, Tom Oomen
Block coordinate descent is an optimization technique that is used for estimating multi-input single-output (MISO) continuous-time models, as well as single-input single output (SISO) models in additive form.
no code implementations • 8 Feb 2024 • Javad Parsa, Cristian R. Rojas, Håkan Hjalmarsson
The maximum absolute correlation between regressors, which is called mutual coherence, plays an essential role in sparse estimation.
no code implementations • 2 Jan 2024 • Rodrigo A. González, Koen Classens, Cristian R. Rojas, James S. Welsh, Tom Oomen
When identifying electrical, mechanical, or biological systems, parametric continuous-time identification methods can lead to interpretable and parsimonious models when the model structure aligns with the physical properties of the system.
no code implementations • 20 Nov 2023 • Braghadeesh Lakshminarayanan, Federico Dettù, Cristian R. Rojas, Simone Formentin
In this paper, we present a sim2real, direct data-driven controller tuning approach, where the digital twin is used to generate input-output data and suitable controllers for several perturbations in its parameters.
no code implementations • 12 Jun 2023 • Francesco Quinzan, Ashkan Soleymani, Patrick Jaillet, Cristian R. Rojas, Stefan Bauer
Knowing the features of a complex system that are highly relevant to a particular target variable is of fundamental interest in many areas of science.
no code implementations • 31 May 2023 • Rodrigo A. González, Cristian R. Rojas, Siqi Pan, James S. Welsh
The Refined Instrumental Variable method for discrete-time systems (RIV) and its variant for continuous-time systems (RIVC) are popular methods for the identification of linear systems in open-loop.
no code implementations • 5 May 2023 • Paweł Wachel, Krzysztof Kowalczyk, Cristian R. Rojas
We study the problem of diffusion-based network learning of a nonlinear phenomenon, $m$, from local agents' measurements collected in a noisy environment.
no code implementations • 6 Apr 2023 • Rodrigo A. González, Angel L. Cedeño, María Coronel, Juan C. Agüero, Cristian R. Rojas
This paper concerns the identification of continuous-time systems in state-space form that are subject to Lebesgue sampling.
no code implementations • 6 Apr 2023 • Rodrigo A. González, Cristian R. Rojas, Siqi Pan, James S. Welsh
The identification of electrical, mechanical, and biological systems using data can benefit greatly from prior knowledge extracted from physical modeling.
no code implementations • 4 Apr 2023 • Rebecka Winqvist, Inês Lourenco, Francesco Quinzan, Cristian R. Rojas, Bo Wahlberg
In this framework, an expert agent, referred to as the teacher, modifies the data used by a learning agent, known as the student, to improve its estimation process.
no code implementations • 18 Nov 2022 • Braghadeesh Lakshminarayanan, Cristian R. Rojas
Standard algorithms for differentially private estimation are based on adding an appropriate amount of noise to the output of a traditional point estimation method.
no code implementations • 6 May 2022 • Cristian R. Rojas, Pawel Wachel
In this paper we establish that every (deterministic) non-autonomous, discrete-time, causal, time invariant system has a state-space representation, and discuss its minimality.
no code implementations • 31 Mar 2022 • Braghadeesh Lakshminarayanan, Cristian R. Rojas
One of the most important problems in system identification and statistics is how to estimate the unknown parameters of a given model.
no code implementations • 15 Nov 2021 • Inês Lourenço, Rebecka Winqvist, Cristian R. Rojas, Bo Wahlberg
A classical learning setting typically concerns an agent/student who collects data, or observations, from a system in order to estimate a certain property of interest.
no code implementations • 28 May 2021 • Matias I. Müller, Cristian R. Rojas
We study the problem of regret minimization in a multi-armed bandit setup where the agent is allowed to play multiple arms at each round by spreading the resources usually allocated to only one arm.
no code implementations • 23 Mar 2021 • Siqi Pan, James S. Welsh, Rodrigo A. Gonzalez, Cristian R. Rojas
The Consistency of the Closed-Loop Simplified Refined Instrumental Variable method for Continuous-time system (CLSRIVC) is analysed based on sampled data.
no code implementations • 19 Mar 2021 • Rodrigo A. González, Cristian R. Rojas, Håkan Hjalmarsson
In continuous-time system identification, the intersample behavior of the input signal is known to play a crucial role in the performance of estimation methods.
no code implementations • 9 Dec 2020 • Inês Lourenço, Robert Mattila, Cristian R. Rojas, Bo Wahlberg
We consider a cooperative system identification scenario in which an expert agent (teacher) knows a correct, or at least a good, model of the system and aims to assist a learner-agent (student), but cannot directly transfer its knowledge to the student.
no code implementations • L4DC 2020 • Rodrigo A. González, Cristian R. Rojas
In this paper, we study non-asymptotic deviation bounds of the least squares estimator in Gaussian AR($n$) processes.
no code implementations • ICML 2018 • Othmane Mazhar, Cristian R. Rojas, Carlo Fischione, Mohammad R. Hesamzadeh
We address the new problem of estimating a piece-wise constant signal with the purpose of detecting its change points and the levels of clusters.
no code implementations • 26 Jul 2015 • Dimitrios Katselis, Cristian R. Rojas, Carolyn L. Beck
The separation of the system estimator from the experiment design is done within this new framework by choosing and fixing the estimation method to either a maximum likelihood (ML) approach or a Bayesian estimator such as the minimum mean square error (MMSE).
no code implementations • 22 Jul 2015 • Robert Mattila, Cristian R. Rojas, Bo Wahlberg
Often, when applied in practice, the parameters of these models have to be estimated.
no code implementations • 23 Jan 2015 • Martin Sundin, Cristian R. Rojas, Magnus Jansson, Saikat Chatterjee
We develop latent variable models for Bayesian learning based low-rank matrix completion and reconstruction from linear measurements.
no code implementations • 1 Dec 2014 • Cristian R. Rojas, Bo Wahlberg
It is known that TV denoising suffers from the so-called stair-case effect, which leads to detecting false change points.
no code implementations • 22 Jul 2014 • Niclas Blomberg, Cristian R. Rojas, Bo Wahlberg
This paper concerns model reduction of dynamical systems using the nuclear norm of the Hankel matrix to make a trade-off between model fit and model complexity.
no code implementations • 30 Jun 2014 • Martin Sundin, Saikat Chatterjee, Magnus Jansson, Cristian R. Rojas
In this paper we develop a new Bayesian inference method for low rank matrix reconstruction.
no code implementations • 21 Jan 2014 • Cristian R. Rojas, Bo Wahlberg
In this paper we analyze the asymptotic properties of l1 penalized maximum likelihood estimation of signals with piece-wise constant mean values and/or variances.