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253 results on '"Alepis, Efthimios"'

2. Paving the Way for the Post-COVID-19 Era

Author

Kontogianni, Aristea, Alepis, Efthimios, Virvou, Maria, Patsakis, Constantinos, Kacprzyk, Janusz, Series Editor, Jain, Lakhmi C., Series Editor, Kontogianni, Aristea, Alepis, Efthimios, Virvou, Maria, and Patsakis, Constantinos

Published
2024
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3. Conceptualizing Smart Tourism

Author

Kontogianni, Aristea, Alepis, Efthimios, Virvou, Maria, Patsakis, Constantinos, Kacprzyk, Janusz, Series Editor, Jain, Lakhmi C., Series Editor, Kontogianni, Aristea, Alepis, Efthimios, Virvou, Maria, and Patsakis, Constantinos

Published
2024
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6. Open Questions and Future Directions

Author

Kontogianni, Aristea, Alepis, Efthimios, Virvou, Maria, Patsakis, Constantinos, Kacprzyk, Janusz, Series Editor, Jain, Lakhmi C., Series Editor, Kontogianni, Aristea, Alepis, Efthimios, Virvou, Maria, and Patsakis, Constantinos

Published
2024
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7. Smart Tourism Embraces Blockchain

Author

Kontogianni, Aristea, Alepis, Efthimios, Virvou, Maria, Patsakis, Constantinos, Kacprzyk, Janusz, Series Editor, Jain, Lakhmi C., Series Editor, Kontogianni, Aristea, Alepis, Efthimios, Virvou, Maria, and Patsakis, Constantinos

Published
2024
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8. Artificial Intelligence in Smart Tourism

Author

Kontogianni, Aristea, Alepis, Efthimios, Virvou, Maria, Patsakis, Constantinos, Kacprzyk, Janusz, Series Editor, Jain, Lakhmi C., Series Editor, Kontogianni, Aristea, Alepis, Efthimios, Virvou, Maria, and Patsakis, Constantinos

Published
2024
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10. Introduction

Author

Kontogianni, Aristea, Alepis, Efthimios, Virvou, Maria, Patsakis, Constantinos, Kacprzyk, Janusz, Series Editor, Jain, Lakhmi C., Series Editor, Kontogianni, Aristea, Alepis, Efthimios, Virvou, Maria, and Patsakis, Constantinos

Published
2024
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11. Conclusions

Author

Kontogianni, Aristea, Alepis, Efthimios, Virvou, Maria, Patsakis, Constantinos, Kacprzyk, Janusz, Series Editor, Jain, Lakhmi C., Series Editor, Kontogianni, Aristea, Alepis, Efthimios, Virvou, Maria, and Patsakis, Constantinos

Published
2024
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12. Hello Me, Meet the Real Me: Audio Deepfake Attacks on Voice Assistants

Author

Bilika, Domna, Michopoulou, Nikoletta, Alepis, Efthimios, and Patsakis, Constantinos

Subjects
Computer Science - Cryptography and Security
Abstract

The radical advances in telecommunications and computer science have enabled a myriad of applications and novel seamless interaction with computing interfaces. Voice Assistants (VAs) have become a norm for smartphones, and millions of VAs incorporated in smart devices are used to control these devices in the smart home context. Previous research has shown that they are prone to attacks, leading vendors to countermeasures. One of these measures is to allow only a specific individual, the device's owner, to perform possibly dangerous tasks, that is, tasks that may disclose personal information, involve monetary transactions etc. To understand the extent to which VAs provide the necessary protection to their users, we experimented with two of the most widely used VAs, which the participants trained. We then utilised voice synthesis using samples provided by participants to synthesise commands that were used to trigger the corresponding VA and perform a dangerous task. Our extensive results showed that more than 30\% of our deepfake attacks were successful and that there was at least one successful attack for more than half of the participants. Moreover, they illustrate statistically significant variation among vendors and, in one case, even gender bias. The outcomes are rather alarming and require the deployment of further countermeasures to prevent exploitation, as the number of VAs in use is currently comparable to the world population.

Published
2023

15. An Application of Self-Assessment of Students in Mathematics with Intelligent Decision Systems: Questionnaire, Design and Implementation at Digital Education

Author

Matzavela, Vasiliki and Alepis, Efthimios

Abstract

During the last decade an eruptive increase in the demand for intelligent m-learning environments has been observed since instructors in the online academic procedures need to ensure reliability. The research for decision systems seemed inevitable for flexible and effective learning in all levels of education. The prediction of the performance of students during their final exams is considered as a difficult task. In this paper, an application is presented, contributing to an accurate prediction which would assist educators and learning experts in the extraction of useful knowledge for designing learning interventions with enhanced outcomes.

Published
2023
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17. Privacy in the COVID-19 Era

Author

Politou, Eugenia, Alepis, Efthimios, Virvou, Maria, Patsakis, Constantinos, Tsihrintzis, George A., Series Editor, Virvou, Maria, Series Editor, Jain, Lakhmi C., Series Editor, Politou, Eugenia, Alepis, Efthimios, and Patsakis, Constantinos

Published
2022
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18. Privacy in Ubiquitous Mobile Computing

Author

Politou, Eugenia, Alepis, Efthimios, Virvou, Maria, Patsakis, Constantinos, Tsihrintzis, George A., Series Editor, Virvou, Maria, Series Editor, Jain, Lakhmi C., Series Editor, Politou, Eugenia, Alepis, Efthimios, and Patsakis, Constantinos

Published
2022
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19. Implementing Content Erasure in IPFS

Author

Politou, Eugenia, Alepis, Efthimios, Virvou, Maria, Patsakis, Constantinos, Tsihrintzis, George A., Series Editor, Virvou, Maria, Series Editor, Jain, Lakhmi C., Series Editor, Politou, Eugenia, Alepis, Efthimios, and Patsakis, Constantinos

Published
2022
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20. Privacy in Blockchain

Author

Politou, Eugenia, Alepis, Efthimios, Virvou, Maria, Patsakis, Constantinos, Tsihrintzis, George A., Series Editor, Virvou, Maria, Series Editor, Jain, Lakhmi C., Series Editor, Politou, Eugenia, Alepis, Efthimios, and Patsakis, Constantinos

Published
2022
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21. State-of-the-Art Technological Developments

Author

Politou, Eugenia, Alepis, Efthimios, Virvou, Maria, Patsakis, Constantinos, Tsihrintzis, George A., Series Editor, Virvou, Maria, Series Editor, Jain, Lakhmi C., Series Editor, Politou, Eugenia, Alepis, Efthimios, and Patsakis, Constantinos

Published
2022
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23. Introduction

Author

Politou, Eugenia, Alepis, Efthimios, Virvou, Maria, Patsakis, Constantinos, Tsihrintzis, George A., Series Editor, Virvou, Maria, Series Editor, Jain, Lakhmi C., Series Editor, Politou, Eugenia, Alepis, Efthimios, and Patsakis, Constantinos

Published
2022
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24. Privacy and Personal Data Protection

Author

Politou, Eugenia, Alepis, Efthimios, Virvou, Maria, Patsakis, Constantinos, Tsihrintzis, George A., Series Editor, Virvou, Maria, Series Editor, Jain, Lakhmi C., Series Editor, Politou, Eugenia, Alepis, Efthimios, and Patsakis, Constantinos

Published
2022
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25. Open Questions and Future Directions

Author

Politou, Eugenia, Alepis, Efthimios, Virvou, Maria, Patsakis, Constantinos, Tsihrintzis, George A., Series Editor, Virvou, Maria, Series Editor, Jain, Lakhmi C., Series Editor, Politou, Eugenia, Alepis, Efthimios, and Patsakis, Constantinos

Published
2022
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26. The General Data Protection Regulation

Author

Politou, Eugenia, Alepis, Efthimios, Virvou, Maria, Patsakis, Constantinos, Tsihrintzis, George A., Series Editor, Virvou, Maria, Series Editor, Jain, Lakhmi C., Series Editor, Politou, Eugenia, Alepis, Efthimios, and Patsakis, Constantinos

Published
2022
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27. Conclusions

Author

Politou, Eugenia, Alepis, Efthimios, Virvou, Maria, Patsakis, Constantinos, Tsihrintzis, George A., Series Editor, Virvou, Maria, Series Editor, Jain, Lakhmi C., Series Editor, Politou, Eugenia, Alepis, Efthimios, and Patsakis, Constantinos

Published
2022
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28. M-Learning in the COVID-19 Era: Physical vs Digital Class

Author

Matzavela, Vasiliki and Alepis, Efthimios

Abstract

Emerging technologies, such as the development of the Internet of Things and the transition to smart cities, and innovative handheld devices have led to big changes in many aspects of our lives, while more changes were imminent. Education is also a sector that has undergone huge changes due to the spreading of those devices. Even at the era of feature phones, it started to become clear that portable devices with access to the internet can be used for learning. The process of learning with the use of mobile phones was then in an early stage, due to the limitations of feature phones. Whereas, with the introduction of smartphones, education is expected to be drastically altered in the future, in most parts of the world. New, radical, and controversial in some cases, approaches have been developed, over the past years, in an effort to implement a mobile learning process in real life conditions. Intelligent tutoring systems have had rapid growth, especially in the COVID-19 era, while a significant increase in online courses via social networks has also been noted. This paper focuses on presenting the most important research parameters of m-learning during the last decade, while it also incorporates a novel empirical study in the domain. The utilization of educational data has been taken into consideration and is presented, aiming at ways to improve human interaction in the digital classroom.

Published
2021
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29. Blockchain Mutability: Challenges and Proposed Solutions

Author

Politou, Eugenia, Casino, Fran, Alepis, Efthimios, and Patsakis, Constantinos

Subjects
Computer Science - Cryptography and Security
Abstract

Blockchain's evolution during the past decade is astonishing: from bitcoin to over 2.000 altcoins, and from decentralised electronic payments to transactions programmable by smart contracts and complex tokens governed by decentralised organisations. While the new generation of blockchain applications is still evolving, blockchain's technical characteristics are also advancing. Yet, immutability, a hitherto indisputable property according to which blockchain data cannot be edited nor deleted, remains the cornerstone of blockchain's security. Nevertheless, blockchain's immutability is being called into question lately in the light of the new erasing requirements imposed by the GDPR's ``\textit{Right to be Forgotten (RtbF)}'' provision. As the RtbF obliges blockchain data to be editable in order restricted content redactions, modifications or deletions to be applied when requested, blockchains compliance with the regulation is indeed challenging, if not impracticable. Towards resolving this contradiction, various methods and techniques for mutable blockchains have been proposed in an effort to satisfy regulatory erasing requirements while preserving blockchains' security. To this end, this work aims to provide a comprehensive review on the state-of-the-art research approaches, technical workarounds and advanced cryptographic techniques that have been put forward to resolve this conflict and to discuss their potentials, constraints and limitations when applied in the wild to either permissioned or permissionless blockchains., Comment: Preprint version

Published
2019

31. Knock-Knock: The unbearable lightness of Android Notifications

Author

Patsakis, Constantinos and Alepis, Efthimios

Subjects
Computer Science - Cryptography and Security
Abstract

Android Notifications can be considered as essential parts in Human-Smartphone interaction and inextricable modules of modern mobile applications that can facilitate User Interaction and improve User Experience. This paper presents how this well-crafted and thoroughly documented mechanism, provided by the OS can be exploited by an adversary. More precisely, we present attacks that result either in forging smartphone application notifications to lure the user in disclosing sensitive information, or manipulate Android Notifications to launch a Denial of Service attack to the users' device, locally and remotely, rendering them unusable. This paper concludes by proposing generic countermeasures for the discussed security threats., Comment: Presented at International Conference on Information Systems Security and Privacy (ICISSP 2018)

Published
2018

40. User Behavioral Biometrics and Machine Learning Towards Improving User Authentication in Smartphones

Author

Torres, José, de los Santos, Sergio, Alepis, Efthimios, Patsakis, Constantinos, Filipe, Joaquim, Editorial Board Member, Ghosh, Ashish, Editorial Board Member, Kotenko, Igor, Editorial Board Member, Prates, Raquel Oliveira, Editorial Board Member, Zhou, Lizhu, Editorial Board Member, Mori, Paolo, editor, Furnell, Steven, editor, and Camp, Olivier, editor

Published
2020
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43. Introduction

Author

Politou, Eugenia, primary, Alepis, Efthimios, additional, Virvou, Maria, additional, and Patsakis, Constantinos, additional

Published
2021
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45. Conclusions

Author

Politou, Eugenia, primary, Alepis, Efthimios, additional, Virvou, Maria, additional, and Patsakis, Constantinos, additional

Published
2021
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50. Privacy in Blockchain

Author

Politou, Eugenia, primary, Alepis, Efthimios, additional, Virvou, Maria, additional, and Patsakis, Constantinos, additional

Published
2021
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