141 citations · 266 across the 15 of their papers we have counts for
16 papers
Safe Exploration for Nonlinear Processes Using Online Gaussian Process Learning
Stefano Tonini, Soroush Rastegarpour, Hamid Reza Feyzmahdavian +2
This paper proposes a safe data-driven control framework for nonlinear systems with partially known dynamics. The method ensures stability and constraint satisfaction during online…
Optimal convergence rates of totally asynchronous optimization
Xuyang Wu, Sindri Magnusson, Hamid Reza Feyzmahdavian +1
Asynchronous optimization algorithms are at the core of modern machine learning and resource allocation systems. However, most convergence results consider bounded information dela…
Delay-adaptive step-sizes for asynchronous learning
Xuyang Wu, Sindri Magnusson, Hamid Reza Feyzmahdavian +1
In scalable machine learning systems, model training is often parallelized over multiple nodes that run without tight synchronization. Most analysis results for the related asynchr…
Asynchronous Iterations in Optimization: New Sequence Results and Sharper Algorithmic Guarantees
Hamid Reza Feyzmahdavian, Mikael Johansson
We introduce novel convergence results for asynchronous iterations that appear in the analysis of parallel and distributed optimization algorithms. The results are simple to apply…
Advances in Asynchronous Parallel and Distributed Optimization
Mahmoud Assran, Arda Aytekin, Hamid Feyzmahdavian +2
Motivated by large-scale optimization problems arising in the context of machine learning, there have been several advances in the study of asynchronous parallel and distributed op…
Distributed learning with compressed gradients
Sarit Khirirat, Hamid Reza Feyzmahdavian, Mikael Johansson
Asynchronous computation and gradient compression have emerged as two key techniques for achieving scalability in distributed optimization for large-scale machine learning. This pa…
Analysis and Implementation of an Asynchronous Optimization Algorithm for the Parameter Server
Arda Aytekin, Hamid Reza Feyzmahdavian, Mikael Johansson
This paper presents an asynchronous incremental aggregated gradient algorithm and its implementation in a parameter server framework for solving regularized optimization problems.…
Stability Analysis of Monotone Systems via Max-separable Lyapunov Functions
Hamid Reza Feyzmahdavian, Bart Besselink, Mikael Johansson
We analyze stability properties of monotone nonlinear systems via max-separable Lyapunov functions, motivated by the following observations: first, recent results have shown that a…
An Asynchronous Mini-Batch Algorithm for Regularized Stochastic Optimization
Hamid Reza Feyzmahdavian, Arda Aytekin, Mikael Johansson
Mini-batch optimization has proven to be a powerful paradigm for large-scale learning. However, the state of the art parallel mini-batch algorithms assume synchronous operation or…
Global convergence of the Heavy-ball method for convex optimization
Euhanna Ghadimi, Hamid Reza Feyzmahdavian, Mikael Johansson
This paper establishes global convergence and provides global bounds of the convergence rate of the Heavy-ball method for convex optimization problems. When the objective function…
Sub-homogeneous positive monotone systems are insensitive to heterogeneous time-varying delays
Hamid Reza Feyzmahdavian, Themistoklis Charalambous, Mikael Johansson
We show that a sub-homogeneous positive monotone system with bounded heterogeneous time-varying delays is globally asymptotically stable if and only if the corresponding delay-free…
Asymptotic Stability and Decay Rates of Homogeneous Positive Systems With Bounded and Unbounded Delays
Hamid Reza Feyzmahdavian, Themistoklis Charalambous, Mikael Johansson
There are several results on the stability of nonlinear positive systems in the presence of time delays. However, most of them assume that the delays are constant. This paper consi…
Exponential Stability of Homogeneous Positive Systems of Degree One With Time-Varying Delays
Hamid Reza Feyzmahdavian, Themistoklis Charalambous, Mikael Johansson
While the asymptotic stability of positive linear systems in the presence of bounded time delays has been thoroughly investigated, the theory for nonlinear positive systems is cons…
Optimal Distributed Controller Design with Communication Delays: Application to Vehicle Formations
Hamid Reza Feyzmahdavian, Assad Alam, Ather Gattami
This paper develops a controller synthesis algorithm for distributed LQG control problems under output feedback. We consider a system consisting of three interconnected linear subs…
Distributed Output-Feedback LQG Control with Delayed Information Sharing
Hamid Reza Feyzmahdavian, Ather Gattami, Mikael Johansson
This paper develops a controller synthesis method for distributed LQG control problems under output-feedback. We consider a system consisting of three interconnected linear subsyst…
Contractive Interference Functions and Rates of Convergence of Distributed Power Control Laws
Hamid Reza Feyzmahdavian, Mikael Johansson, Themistoklis Charalambous
The standard interference functions introduced by Yates have been very influential on the analysis and design of distributed power control laws. While powerful and versatile, the f…