Georgios Leontidis

Dr. Georgios Leontidis


Research Focus & Metrics

Academic Career Length

13Years (2014-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 March 2019 in Global Food Security
Verified
Journal Article
Open access
Simon PearsonSimon Pearson
Simon Pearson
DMDavid May
David May
GLGeorgios Leontidis
Georgios Leontidis
MSMark Swainson
Mark Swainson
SBSteve Brewer
Steve Brewer
AZAndrea Zisman
Andrea Zisman

1 March 2021 in Computers in Biology and Medicine
Verified
Journal Article
Closed access
SKStefanos Karakanis
Stefanos Karakanis
GLGeorgios Leontidis
Georgios Leontidis

1 March 2021 in Global Food Security
Verified
Journal Article
Closed access
ADAiden Durrant
Aiden Durrant
MMMilan Markovic
Milan Markovic
DMDavid Matthews
David Matthews
DMDavid May
David May
GLGeorgios Leontidis
Georgios Leontidis
JEJessica Enright
Jessica Enright

3 April 2020 in Proceedings of the AAAI Conference on Artificial Intelligence
Verified
Journal Article
Closed access
PDF file
FRFabio De Sousa Ribeiro
Fabio De Sousa Ribeiro
GLGeorgios Leontidis
Georgios Leontidis
SKStefanos Kollias
Stefanos Kollias
Capsule networks are a recently proposed type of neural network shown to outperform alternatives in challenging shape recognition tasks. In capsule networks, scalar neurons are replaced with capsule vectors or matrices, whose entries represent different properties of objects. The relationships between objects and their parts are learned via trainable viewpoint-invariant transformation matrices, and the presence of a given object is decided by the level of agreement among votes from its parts. This interaction occurs between capsule layers and is a process called routing-by-agreement. In this paper, we propose a new capsule routing algorithm derived from Variational Bayes for fitting a mixture of transforming gaussians, and show it is possible transform our capsule network into a Capsule-VAE. Our Bayesian approach addresses some of the inherent weaknesses of MLE based models such as the variance-collapse by modelling uncertainty over capsule pose parameters. We outperform the state-of-the-art on smallNORB using ≃50% fewer capsules than previously reported, achieve competitive performances on CIFAR-10, Fashion-MNIST, SVHN, and demonstrate significant improvement in MNIST to affNIST generalisation over previous works.1

1 July 2018
Verified
Conference Paper
Open access
FCFrancesco Caliva
Francesco Caliva
FRFabio Sousa De Ribeiro
Fabio Sousa De Ribeiro
AMAntonios Mylonakis
Antonios Mylonakis
CDChristophe Demazirere
Christophe Demazirere
PVPaolo Vinai
Paolo Vinai
SKStefanos Kollias
Stefanos Kollias
In this work, a novel deep learning approach to unfold nuclear power reactor signals is proposed. It includes a combination of convolutional neural networks (CNN), denoising autoencoders (DAE) and k-means clustering of representations. Monitoring nuclear reactors while running at nominal conditions is critical. Based on analysis of the core reactor neutron flux, it is possible to derive useful information for building fault/anomaly detection systems. By leveraging signal and image pre-processing techniques, the high and low energy spectra of the signals were appropriated into a compatible format for CNN training. Firstly, a CNN was employed to unfold the signal into either twelve or forty-eight perturbation location sources, followed by a k-means clustering and k-Nearest Neighbour coarse-to-fine procedure, which significantly increases the unfolding resolution. Secondly, a DAE was utilised to denoise and reconstruct power reactor signals at varying levels of noise and/or corruption. The reconstructed signals were evaluated w.r.t. their original counter parts, by way of normalised cross correlation and unfolding metrics. The results illustrate that the origin of perturbations can be localised with high accuracy, despite limited training data and obscured/noisy signals, across various levels of granularity.

1 September 2020 in Journal of Hydrology
Verified
Journal Article
Closed access
BCBenedict D. Chivers
Benedict D. Chivers
JWJohn Wallbank
John Wallbank
SCSteven J. Cole
Steven J. Cole
OSOndrej Sebek
Ondrej Sebek
SSSimon Stanley
Simon Stanley
GLGeorgios Leontidis
Georgios Leontidis