no code implementations • 17 Jan 2024 • Dajiang Sun, Christoforos N. Hadjicostis, Zhiwu Li
Two types of errors, global errors and local errors, are proposed to describe the impact of errors on decentralized information processing.
no code implementations • 2 Apr 2023 • Apostolos I. Rikos, Andreas Grammenos, Evangelia Kalyvianaki, Christoforos N. Hadjicostis, Themistoklis Charalambous, Karl H. Johansson
We prove that our algorithms converge in a finite number of iterations to the exact optimal solution depending on the quantization level, and we present applications of our algorithms to (i) optimal task scheduling for data centers, and (ii) global model aggregation for distributed federated learning.
no code implementations • 29 Nov 2022 • Apostolos I. Rikos, Themistoklis Charalambous, Christoforos N. Hadjicostis, Karl H. Johansson
We present two distributed algorithms which rely on quantized operation (i. e., nodes process and transmit quantized messages), and are able to calculate the exact solutions in a finite number of steps.
no code implementations • 29 Sep 2022 • Evagoras Makridis, Themistoklis Charalambous, Christoforos N. Hadjicostis
In this paper, we address the discrete-time average consensus problem, where nodes exchange information over unreliable communication links.
no code implementations • 30 Aug 2022 • Mohammadreza Doostmohammadian, Alireza Aghasi, Apostolos I. Rikos, Andreas Grammenos, Evangelia Kalyvianaki, Christoforos N. Hadjicostis, Karl H. Johansson, Themistoklis Charalambous
This paper considers a network of collaborating agents for local resource allocation subject to nonlinear model constraints.
no code implementations • 17 Jul 2022 • Apostolos I. Rikos, Christoforos N. Hadjicostis, Karl H. Johansson
Furthermore, we present topological conditions under which the proposed algorithm allows nodes to preserve their privacy.
no code implementations • 17 Jul 2022 • Apostolos I. Rikos, Christoforos N. Hadjicostis, Karl H. Johansson
In this paper, we focus on the problem of data sharing over a wireless computer network (i. e., a wireless grid).
no code implementations • 17 Jul 2022 • Apostolos I. Rikos, Gabriele Oliva, Christoforos N. Hadjicostis, Karl H. Johansson
The goal of $k$-means is to partition the network's agents in mutually exclusive sets (groups) such that agents in the same set have (and possibly share) similar information and are able to calculate a representative value for their group. During the operation of our distributed algorithm, each node (i) transmits quantized values in an event-driven fashion, and (ii) exhibits distributed stopping capabilities.
no code implementations • 8 Nov 2021 • Nicolaos E. Manitara, Apostolos I. Rikos, Christoforos N. Hadjicostis
In this paper, we develop and analyze a gossip-based average consensus algorithm that enables all of the components of a distributed system, each with some initial value, to reach (approximate) average consensus on their initial values after executing a finite number of iterations, and without having to reveal the specific value they contribute to the average calculation.
no code implementations • 1 Oct 2021 • Apostolos I. Rikos, Christoforos N. Hadjicostis, Karl H. Johansson
Motivated by these novel requirements, in this paper, we present and analyze a novel distributed average consensus algorithm, which (i) operates exclusively on quantized values (in order to guarantee efficient communication and data storage), and (ii) relies on event-driven updates (in order to reduce energy consumption, communication bandwidth, network congestion, and/or processor usage).
no code implementations • 15 Dec 2013 • Gabriele Oliva, Roberto Setola, Christoforos N. Hadjicostis
Since the partitions may not have a relation with the topology of the network--members of the same clusters may not be spatially close--the algorithm is provided with a mechanism to compute the clusters'centroids even when the clusters are disconnected in several sub-clusters. The results of the proposed distributed algorithm coincide, in terms of minimization of the objective function, with the centralized k-means algorithm.