G
George Tzagkarakis
Researcher at Foundation for Research & Technology – Hellas
Publications - 68
Citations - 757
George Tzagkarakis is an academic researcher from Foundation for Research & Technology – Hellas. The author has contributed to research in topics: Compressed sensing & Wireless sensor network. The author has an hindex of 13, co-authored 64 publications receiving 683 citations. Previous affiliations of George Tzagkarakis include DSM & French Alternative Energies and Atomic Energy Commission.
Papers
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Journal ArticleDOI
Low-dimensional signal-strength fingerprint-based positioning in wireless LANs
Dimitris Milioris,George Tzagkarakis,Artemis Papakonstantinou,Maria Papadopouli,Panagiotis Tsakalides +4 more
TL;DR: A suite of novel indoor positioning techniques utilizing signal-strength fingerprints collected from access points and compressive sensing to perform sparsity-based accurate indoor localization, while reducing significantly the amount of information transmitted from a wireless device, possessing limited power, storage, and processing capabilities, to a central server is introduced.
Journal ArticleDOI
Rotation-invariant texture retrieval with gaussianized steerable pyramids
TL;DR: This paper presents a novel rotation-invariant image retrieval scheme based on a transformation of the texture information via a steerable pyramid using a joint alpha-stable sub-Gaussian model and a normalization process to Gaussianize the coefficients.
Proceedings ArticleDOI
Compressive sensing for ultrasound RF echoes using a-Stable Distributions
TL;DR: An approach to ℓp norm minimisation that employs the iteratively reweighted least squares (IRLS) algorithm but in which the parameter p is judiciously chosen by relating it to the characteristic exponent of the underlying alpha-stable distributed data.
Proceedings ArticleDOI
Multiple-measurement Bayesian compressed sensing using GSM priors for DOA estimation
TL;DR: This paper develops a Bayesian CS (BCS) approach for estimating target bearings based on multiple noisy CS measurement vectors, where each vector results by projecting the received source signal on distinct over-complete dictionaries.
Proceedings ArticleDOI
Empirical evaluation of signal-strength fingerprint positioning in wireless LANs
Dimitris Milioris,Lito Kriara,Artemis Papakonstantinou,George Tzagkarakis,Panagiotis Tsakalides,Maria Papadopouli +5 more
TL;DR: This paper proposes a novel localization technique based on a multivariate Gaussian modeling of the signal strength measurements collected from several access points (APs) at different locations and considers a discretized grid-like form of the environment and computes a signature at each cell of the grid.