Mihalis Psarakis

Prof. Mihalis Psarakis

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Research Focus & Metrics

Academic Career Length

19Years (2008-Present)

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

Representative Publications

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12 July 2018 in IEEE Communications Surveys & Tutorials
Verified
Journal Article
Closed access
ISIoannis Stellios
Ioannis Stellios
Panayiotis KotzanikolaouPanayiotis Kotzanikolaou
Panayiotis Kotzanikolaou
MPMihalis Psarakis
Mihalis Psarakis
Crisitna AlcarazCrisitna Alcaraz
Crisitna Alcaraz
Javier LopezJavier Lopez
Javier Lopez
As the deployment of Internet of Things (IoT) is experiencing an exponential growth, it is no surprise that many recent cyber attacks are IoT-enabled: The attacker initially exploits some vulnerable IoT technology as a first step towards compromising a critical system that is connected, in some way, with the IoT. For some sectors, like industry, smart grids, transportation and medical services, the significance of such attacks is obvious, since IoT technologies are part of critical back-end systems. However, in sectors where IoT is usually at the end-user side, like smart homes, such attacks can be underestimated, since not all possible attack paths are examined. In this paper we survey IoT-enabled cyber attacks, found in all application domains since 2010. For each sector, we emphasize on the latest, verified IoT-enabled attacks, based on known real-world incidents and published proof-of-concept attacks. We methodologically analyze representative attacks that demonstrate direct, indirect and subliminal attack paths against critical targets. Our goal is threefold: (i) To assess IoT-enabled cyber attacks in a risk-like approach, in order to demonstrate their current threat landscape; (ii) To identify hidden and subliminal IoT-enabled attack paths against critical infrastructures and services, and (iii) To examine mitigation strategies for all application domains.

28 September 2018 in Algorithms
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Journal Article
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AAAbdoalnasir Mouftah Almabrok
Abdoalnasir Mouftah Almabrok
MPMihalis Psarakis
Mihalis Psarakis
Anastasios Isidoros DounisAnastasios Isidoros Dounis
Anastasios Isidoros Dounis
This article presents a novel technique for the fast tuning of the parameters of the proportional–integral–derivative (PID) controller of a second-order heat, ventilation, and air conditioning (HVAC) system. The HVAC systems vary greatly in size, control functions and the amount of consumed energy. The optimal design and power efficiency of an HVAC system depend on how fast the integrated controller, e.g., PID controller, is adapted in the changes of the environmental conditions. In this paper, to achieve high tuning speed, we rely on a fast convergence evolution algorithm, called Big Bang–Big Crunch (BB–BC). The BB–BC algorithm is implemented, along with the PID controller, in an FPGA device, in order to further accelerate of the optimization process. The FPGA-in-the-loop (FIL) technique is used to connect the FPGA board (i.e., the PID and BB–BC subsystems) with the plant (i.e., MATLAB/Simulink models of HVAC) in order to emulate and evaluate the entire system. The experimental results demonstrate the efficiency of the proposed technique in terms of optimization accuracy and convergence speed compared with other optimization approaches for the tuning of the PID parameters: sw implementation of the BB–BC, genetic algorithm (GA), and particle swarm optimization (PSO).

8 January 2010 in IEEE Transactions on Dependable and Secure Computing
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Journal Article
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JCJacques Henri Collet
Jacques Henri Collet
Piotr ZającPiotr Zając
Piotr Zając
MPMihalis Psarakis
Mihalis Psarakis
DGDimitris Gizopoulos
Dimitris Gizopoulos
We study chip self-organization and fault tolerance at the architectural level to improve dependable continuous operation of multicore arrays in massively defective nanotechnologies. Architectural self-organization results from the conjunction of self-diagnosis and self-disconnection mechanisms (to identify and isolate most permanently faulty or inaccessible cores and routers), plus self-discovery of routes to maintain the communication in the array. In the methodology presented in this work, chip self-diagnosis is performed in three steps, following an ascending order of complexity: interconnects are tested first, then routers through mutual test, and cores in the last step. The mutual testing of routers is especially important as faulty routers are disconnected by good ones with no assumption on the behavior of defective elements. Moreover, the disconnection of faulty routers is not physical (“hard”) but logical (“soft”) in that a good router simply stops communicating with any adjacent router diagnosed as defective. There is no physical reconfiguration in the chip and no need for spare elements. Ultimately, the multicore array may be viewed as a black box, which incorporates protection mechanisms and self-organizes, while the external control reduces to a simple chip validation test which, in the simplest cases, reduces to counting the number of valid and accessible cores.

22 October 2020 in IEEE Transactions on Nuclear Science
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Journal Article
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VVVasileios Vlagkoulis
Vasileios Vlagkoulis
ASAitzan Sari
Aitzan Sari
JVJohn Vrachnis
John Vrachnis
GAGeorgios Antonopoulos
Georgios Antonopoulos
NSNikolaos Segkos
Nikolaos Segkos
CSChristoph Schuy
Christoph Schuy
This paper studies the impact of radiation-induced Single Event Effects (SEEs) in the Zynq-7000 FPGA and presents an in-depth analysis of the SEE susceptibility of all the memories of the programmable logic. The radiation experiments were per-formed in the CERN North Area facility and in the GSI Helmholtz Centre for Heavy Ion Research using very/ultra-high energy heavy ions. The offline analysis of the radiation experimental results pro-duced a deep understanding for various SEE phenomena observed in the Zynq-7000 FPGAs, such as SEFIs, SET in global signals and multiple bit upsets that could be key issues for the design of an effective SEE mitigation approach.

19 February 2020 in Journal of Signal Processing Systems
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MPMihalis Psarakis
Mihalis Psarakis
Anastasios Isidoros DounisAnastasios Isidoros Dounis
Anastasios Isidoros Dounis
AAAbdoalnasir Almabrok
Abdoalnasir Almabrok
SSStavros Stavrinidis
Stavros Stavrinidis
GGGeorgios Gkekas
Georgios Gkekas

15 February 2022 in IEEE Transactions on Nuclear Science
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Journal Article
Closed access
VVVasileios Vlagkoulis
Vasileios Vlagkoulis
ASAitzan Sari
Aitzan Sari
GAGeorgios Antonopoulos
Georgios Antonopoulos
MPMihalis Psarakis
Mihalis Psarakis
ATAntonios Tavoularis
Antonios Tavoularis
RARuben Garcia Alia
Ruben Garcia Alia
SRAM-based field-programmable gate array (FPGA) vendors typically integrate error correction codes (ECCs) into the configuration memory to assist designers in implementing scrubbing mechanisms. In most cases, these ECC schemes guarantee the correction of single- and double-bit errors per configuration frame but fail to correct upsets with higher multiplicity in a single frame caused by a single event. This phenomenon has been observed in modern commercial-off-the-shelf FPGAs. Bit interleaving schemes are used in some FPGA families to scatter the multiple upsets into more than one frame, but this does not fully resolve the problem of uncorrectable errors. In this article, we propose a configuration memory scrubbing approach for SRAM-based FPGA devices, which combines the embedded ECC logic with an interframe, interleaved parity code to build a mixed 2-D coding technique. The proposed technique improves the multiple-bit error correction capabilities of the on-chip ECC scheme while keeping the error correction latency and hardware cost low. The scrubbing concept has been validated under heavy-ion irradiation, where it succeeded in correcting all the single and multiple upsets observed during the radiation experiment.