Spyros T. Halkidis

Dr. Spyros T. Halkidis

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Research Focus & Metrics

Academic Career Length

29Years (1998-Present)

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

Representative Publications

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20 November 2006 in IEEE Transactions on Software Engineering
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Journal Article
Closed access
NTNikolaos Tsantalis
Nikolaos Tsantalis
ACAlexander Chatzigeorgiou
Alexander Chatzigeorgiou
GSGeorge Stephanides
George Stephanides
SHSpyros T. Halkidis
Spyros T. Halkidis
The identification of design patterns as part of the reengineering process can convey important information to the designer. However, existing pattern detection methodologies generally have problems in dealing with one or more of the following issues: identification of modified pattern versions, search space explosion for large systems and extensibility to novel patterns. In this paper, a design pattern detection methodology is proposed that is based on similarity scoring between graph vertices. Due to the nature of the underlying graph algorithm, this approach has the ability to also recognize patterns that are modified from their standard representation. Moreover, the approach exploits the fact that patterns reside in one or more inheritance hierarchies, reducing the size of the graphs to which the algorithm is applied. Finally, the algorithm does not rely on any pattern-specific heuristic, facilitating the extension to novel design structures. Evaluation on three open-source projects demonstrated the accuracy and the efficiency of the proposed method

1 October 2012 in Expert Systems with Applications
Verified
Journal Article
Closed access
AIAnastasia Ioannidou
Anastasia Ioannidou
SHSpyros T. Halkidis
Spyros T. Halkidis
GSGeorge Stephanides
George Stephanides

1 June 2000 in Image and Vision Computing
Verified
Journal Article
Closed access
MLM.I.A Lourakis
M.I.A Lourakis
SHSpyros T. Halkidis
Spyros T. Halkidis
SOS.C Orphanoudakis
S.C Orphanoudakis

5 August 2008 in IEEE Transactions on Dependable and Secure Computing
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Journal Article
Closed access
SHSpyros T. Halkidis
Spyros T. Halkidis
NTNikolaos Tsantalis
Nikolaos Tsantalis
ACAlexander Chatzigeorgiou
Alexander Chatzigeorgiou
GSGeorge Stephanides
George Stephanides
The importance of software security has been profound, since most attacks to software systems are based on vulnerabilities caused by poorly designed and developed software. Furthermore, the enforcement of security in software systems at the design phase can reduce the high cost and effort associated with the introduction of security during implementation. For this purpose, security patterns that offer security at the architectural level have been proposed in analogy to the well-known design patterns. The main goal of this paper is to perform risk analysis of software systems based on the security patterns that they contain. The first step is to determine to what extent specific security patterns shield from known attacks. This information is fed to a mathematical model based on the fuzzy-set theory and fuzzy fault trees in order to compute the risk for each category of attacks. The whole process has been automated using a methodology that extracts the risk of a software system by reading the class diagram of the system under study.

29 July 2025 in Applied Sciences
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Journal Article
Open access
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NGNikolaos Orestis Gavriilidis
Nikolaos Orestis Gavriilidis
SHSpyros T. Halkidis
Spyros T. Halkidis
SPSophia Petridou
Sophia Petridou
The rapid growth of Internet of Things (IoT) deployment has led to an unprecedented volume of interconnected, resource-constrained devices. Securing their communication is essential, especially in vehicular environments, where sensitive data exchange requires robust authentication, integrity, and confidentiality guarantees. In this paper, we present an empirical evaluation of TLS (Transport Layer Security)-enhanced MQTT (Message Queuing Telemetry Transport) on low-cost, quad-core Cortex-A72 ARMv8 boards, specifically the Raspberry Pi 4B, commonly used as prototyping platforms for On-Board Units (OBUs) and Road-Side Units (RSUs). Three MQTT entities, namely, the broker, the publisher, and the subscriber, are deployed, utilizing Elliptic Curve Cryptography (ECC) for key exchange and authentication and employing the AES_256_GCM and ChaCha20_Poly1305 ciphers for confidentiality via appropriately selected libraries. We quantify resource consumption in terms of CPU utilization, execution time, energy usage, memory footprint, and goodput across TLS phases, cipher suites, message packaging strategies, and both Ethernet and WiFi interfaces. Our results show that (i) TLS 1.3-enhanced MQTT is feasible on Raspberry Pi 4B devices, though it introduces non-negligible resource overheads; (ii) batching messages into fewer, larger packets reduces transmission cost and latency; and (iii) ChaCha20_Poly1305 outperforms AES_256_GCM, particularly in wireless scenarios, making it the preferred choice for resource- and latency-sensitive V2X applications. These findings provide actionable recommendations for deploying secure MQTT communication on an IoT platform.

31 July 2006 in Computers & Security
Verified
Journal Article
Closed access
SHSpyros T. Halkidis
Spyros T. Halkidis
ACAlexander Chatzigeorgiou
Alexander Chatzigeorgiou
GSGeorge Stephanides
George Stephanides