Search Results for author: Christoforos N. Hadjicostis

Found 11 papers, 0 papers with code

Global and Local Error-Tolerant Decentralized State Estimation under Partially Ordered Observations

no code implementations17 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.

Distributed Optimization for Quadratic Cost Functions over Large-Scale Networks with Quantized Communication and Finite-Time Convergence

no code implementations2 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.

Distributed Optimization Federated Learning +2

Distributed Computation of Exact Average Degree and Network Size in Finite Number of Steps under Quantized Communication

no code implementations29 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.

Quantization

ARQ-based Average Consensus over Unreliable Directed Network Topologies

no code implementations29 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.

Finite Time Privacy Preserving Quantized Average Consensus with Transmission Stopping

no code implementations17 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.

Privacy Preserving

Distributed Finite Time k-means Clustering with Quantized Communucation and Transmission Stopping

no code implementations17 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.

Clustering

Privacy-Preserving Distributed Average Consensus in Finite Time using Random Gossip

no code implementations8 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.

Privacy Preserving

Finite Time Exact Quantized Average Consensus with Limited Resources and Transmission Stopping for Energy-Aware Networks

no code implementations1 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).

Autonomous Vehicles

Distributed k-means algorithm

no code implementations15 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.

Clustering Position

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