Alexandros G. Fragkiadakis

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With the rapid proliferation of new technologies and services in the wireless domain, spectrum scarcity has become a major concern. The allocation of the Industrial, Medical and Scientific (ISM) band has enabled the explosion of new technologies (e.g. Wi-Fi) due to its licence-exempt characteristic. The widespread adoption of Wi-Fi technology, combined with(More)
Cognitive radio (CR) has emerged as a promising technology to exploit the unused portions of spectrum in an opportunistic manner. The fixed spectrum allocation of governmental agencies results in unused portions of spectrum, which are called “spectrum holes” or “white spaces”. CR technology overcomes this issue, allowing devices to sense the spectrum for(More)
The recent advances in micro-sensor hardware technologies, along with the invention of energy-efficient protocols, have enabled a world-wide spread in wireless sensor networks deployment. These networks are used for a large number of purposes, while having small maintenance and deployment costs. However, as these are usually unattended networks, several(More)
The proliferation of wireless networks has been remarkable during the last decade. The license-free nature of the ISM band along with the rapid proliferation of the Wi-Fi-enabled devices, especially the smart phones, has substantially increased the demand for broadband wireless access. However, due to their open nature, wireless networks are susceptible to(More)
In this paper we present and evaluate anomaly-based intrusion detection algorithms for detecting attacks at the physical layer of wireless networks, by seeking for changes in the Signal-to-Noise ratio statistical characteristics. Two types of algorithms are proposed: simple threshold algorithms and cumulative sum (cusum) algorithms. Performance evaluation(More)
In this paper we present and evaluate anomaly-based intrusion detection algorithms for detecting physical layer jamming attacks in wireless networks, by seeking changes in the statistical characteristics of the signal-to-noise ratio (SNR). Two types of algorithms are investigated: simple threshold algorithms and algorithms based on the cumulative sum change(More)
A number of disasters in various places of the planet have caused an extensive loss of lives, severe damages to properties and the environment, as well as a tremendous shock to the survivors. For relief and mitigation operations, emergency responders are immediately dispatched to the disaster areas. Ubiquitous and robust communications during the emergency(More)
As the world becomes an interconnected network where objects and humans interact with each other, new challenges and threats appear in the ecosystem. In this interconnected world, smart objects have an important role in giving users the chance for life-logging in smart environments. However, smart devices have several limitations with regards to memory,(More)
We present intrusion detection algorithms to detect physical layer jamming attacks in wireless networks. We compare the performance of local algorithms on the basis of the signal-to-interference-plus-noise ratio (SINR) executing independently at several monitors, with a collaborative detection algorithm that fuses the outputs provided by these algorithms.(More)
Wireless sensor networks have gained considerable interest in the last few years, serving a large number of applications. Data collection efficiency is of paramount importance as sensors are severe resource-constrained devices, and current protocol inefficiencies lead to significant packet loss. In this work, we minimize the necessary information sensors(More)