no code implementations • 8 Mar 2024 • Muhammad A. Shah, David Solans Noguero, Mikko A. Heikkila, Nicolas Kourtellis
As Automatic Speech Recognition (ASR) models become ever more pervasive, it is important to ensure that they make reliable predictions under corruptions present in the physical and digital world.
Automatic Speech Recognition Automatic Speech Recognition (ASR) +1
no code implementations • 18 Jan 2024 • Dewant Katare, David Solans Noguero, Souneil Park, Nicolas Kourtellis, Marijn Janssen, Aaron Yi Ding
While mainstream research primarily enhances class performance metrics, the hidden traits of bias inheritance in the AI models, class imbalances and disparities within the datasets are often overlooked.
no code implementations • 1 Mar 2023 • Souvik Paul, Nicolas Kourtellis
Machine Learning (ML)-powered apps are used in pervasive devices such as phones, tablets, smartwatches and IoT devices.
no code implementations • 13 Dec 2022 • Panagiotis Papadopoulos, Dimitris Spithouris, Evangelos P. Markatos, Nicolas Kourtellis
Past studies have proposed machine learning-based methods for detecting such fake news, focusing on different properties of the published news articles, such as linguistic characteristics of the actual content, which however have limitations due to the apparent language barriers.
no code implementations • 23 Sep 2022 • Pantelitsa Leonidou, Nicolas Kourtellis, Nikos Salamanos, Michael Sirivianos
In this paper, we propose a privacy-preserving FL framework for online content moderation that incorporates Differential Privacy (DP).
no code implementations • 10 Jun 2022 • Varun Chandrasekaran, Suman Banerjee, Diego Perino, Nicolas Kourtellis
Federated learning (FL), where data remains at the federated clients, and where only gradient updates are shared with a central aggregator, was assumed to be private.
1 code implementation • 29 Apr 2021 • Fan Mo, Hamed Haddadi, Kleomenis Katevas, Eduard Marin, Diego Perino, Nicolas Kourtellis
We propose and implement a Privacy-preserving Federated Learning ($PPFL$) framework for mobile systems to limit privacy leakages in federated learning.
1 code implementation • 16 Mar 2021 • Manolis Chalkiadakis, Alexandros Kornilakis, Panagiotis Papadopoulos, Evangelos P. Markatos, Nicolas Kourtellis
In this paper, we perform a first of its kind investigation to answer such questions regarding the online presence of fake news websites and characterize their behavior in comparison to real news websites.
1 code implementation • 17 Feb 2021 • Emmanouil Papadogiannakis, Panagiotis Papadopoulos, Nicolas Kourtellis, Evangelos P. Markatos
As a result, users' choices play very little role with respect to tracking: we measured that more than 75% of tracking activities happened before users had the opportunity to make a selection in the cookie consent banner, or when users chose to reject all cookies.
Computers and Society Cryptography and Security K.4.2
no code implementations • 18 Nov 2020 • Nicolas Kourtellis, Kleomenis Katevas, Diego Perino
Indeed, FL enables local training on user devices, avoiding user data to be transferred to centralized servers, and can be enhanced with differential privacy mechanisms.
1 code implementation • 20 Aug 2020 • Benjamin Zi Hao Zhao, Mohamed Ali Kaafar, Nicolas Kourtellis
In this work, we empirically evaluate various implementations of differential privacy (DP), and measure their ability to fend off real-world privacy attacks, in addition to measuring their core goal of providing accurate classifications.
Cryptography and Security
no code implementations • 30 Jun 2020 • Beatrice Perez, Sara R. Machado, Jerone T. A. Andrews, Nicolas Kourtellis
Donations to charity-based crowdfunding environments have been on the rise in the last few years.
no code implementations • 17 Jun 2020 • Herodotos Herodotou, Despoina Chatzakou, Nicolas Kourtellis
The rise of online aggression on social media is evolving into a major point of concern.
no code implementations • 20 Jul 2019 • Despoina Chatzakou, Ilias Leontiadis, Jeremy Blackburn, Emiliano De Cristofaro, Gianluca Stringhini, Athena Vakali, Nicolas Kourtellis
We also explore specific manifestations of abusive behavior, i. e., cyberbullying and cyberaggression, in one of the hate-related communities (Gamergate).
1 code implementation • 24 Apr 2019 • Harris Partaourides, Kostantinos Papadamou, Nicolas Kourtellis, Ilias Leontiadis, Sotirios Chatzis
Modern deep learning approaches have achieved groundbreaking performance in modeling and classifying sequential data.
no code implementations • 26 May 2018 • Panagiotis Papadopoulos, Nicolas Kourtellis, Evangelos P. Markatos
In this paper, we perform a first to our knowledge in-depth study of CSync in the wild, using a year-long weblog from 850 real mobile users.
no code implementations • 10 Apr 2018 • Savvas Zannettou, Michael Sirivianos, Jeremy Blackburn, Nicolas Kourtellis
In this work, we pay particular attention to political false information as: 1) it can have dire consequences to the community (e. g., when election results are mutated) and 2) previous work show that this type of false information propagates faster and further when compared to other types of false information.
Social and Information Networks Computers and Society
7 code implementations • 1 Feb 2018 • Antigoni-Maria Founta, Constantinos Djouvas, Despoina Chatzakou, Ilias Leontiadis, Jeremy Blackburn, Gianluca Stringhini, Athena Vakali, Michael Sirivianos, Nicolas Kourtellis
In recent years, offensive, abusive and hateful language, sexism, racism and other types of aggressive and cyberbullying behavior have been manifesting with increased frequency, and in many online social media platforms.
Social and Information Networks 68T06 K.4.2
no code implementations • 1 Feb 2018 • Antigoni-Maria Founta, Despoina Chatzakou, Nicolas Kourtellis, Jeremy Blackburn, Athena Vakali, Ilias Leontiadis
Hate speech, offensive language, sexism, racism and other types of abusive behavior have become a common phenomenon in many online social media platforms.
no code implementations • 24 Feb 2017 • Despoina Chatzakou, Nicolas Kourtellis, Jeremy Blackburn, Emiliano De Cristofaro, Gianluca Stringhini, Athena Vakali
Over the past few years, online aggression and abusive behaviors have occurred in many different forms and on a variety of platforms.
1 code implementation • 22 Feb 2017 • Despoina Chatzakou, Nicolas Kourtellis, Jeremy Blackburn, Emiliano De Cristofaro, Gianluca Stringhini, Athena Vakali
In recent years, bullying and aggression against users on social media have grown significantly, causing serious consequences to victims of all demographics.
Computers and Society Social and Information Networks
no code implementations • 28 Jul 2016 • Nicolas Kourtellis, Gianmarco De Francisci Morales, Albert Bifet, Arinto Murdopo
IoT Big Data requires new machine learning methods able to scale to large size of data arriving at high speed.
2 code implementations • 26 Oct 2015 • Muhammad Anis Uddin Nasir, Gianmarco De Francisci Morales, David Garcia-Soriano, Nicolas Kourtellis, Marco Serafini
We study the problem of load balancing in distributed stream processing engines, which is exacerbated in the presence of skew.
Distributed, Parallel, and Cluster Computing
1 code implementation • 23 Jul 2015 • Robin Devooght, Nicolas Kourtellis, Amin Mantrach
In each case, we outrank state-of-the-art matrix factorization methods that do not use a prior on unknown ratings.