George Violettas | University of Macedonia (original) (raw)

Papers by George Violettas

Future Generation Computer Systems, 2021

Internet of Things (IoT) constitutes a pivotal contributor to the Industry 4.0 (I 4.0) vision, te... more Internet of Things (IoT) constitutes a pivotal contributor to the Industry 4.0 (I 4.0) vision, technologically transforming production and societies. It enables novel services through the seamless integration of devices, such as motes carrying sensors, with the Internet. However, the broad adoption of IoT technologies is facing security issues due to the direct access to the devices from the Internet, the broadcasting nature of the wireless media, and the potential unattended operation of relevant deployments. In particular, the Routing over Low Power and Lossy Networks (RPL) protocol, a prominent IoT solution, is vulnerable to a large number of attacks, both of general-purpose and RPL-specific nature, while the resource-constraints of the corresponding devices are making attack mitigation even more challenging, e.g., in terms of involved control overhead and detection accuracy. In this paper, we introduce ASSET, a novel Intrusion Detection System (IDS) for RPL with diverse profiles to tackle the above issues that mitigate at least 13 attacks. At the same time, other solutions go up to eight. ASSET, inspired by the network softwarization paradigm, supports a novel, extendable workflow, bringing together three anomaly-detection and four RPL specification-based mechanisms, a novel attacker identification process, as well as multiple attack mitigation strategies. Our IDS also supports an adaptable control & monitoring protocol, trading overhead for accuracy, depending on the network conditions. The proof-ofconcept experiments show that ASSET entails a low overhead for the different modes of operation it supports (i.e., 6.28 percent on average) compared to other solutions reaching up to 30 percent. At the same time, it also keeps the power consumption at acceptable levels (from 0.18 up to 1.54 percent more). Moreover, it provides 100 percent accuracy for specific attacks and can identify the attacker in far more attacks than any other similar solution.

Elsevier Computers & Security, 2021

Internet of Things (IoT) is an emerging technology that has seen remarkable blossom over the last... more Internet of Things (IoT) is an emerging technology that has seen remarkable blossom over the last years. The growing interest for IPv6 constrained networks has made the Routing Protocol for Low Power and Lossy Networks (RPL) the standard routing solution, which has gained significant attention and maturity in the literature. However, due to the networks' open and possibly unattended environment of operation, as well as to the nodes' constraints, the security of the protocol is a challenging issue, currently under thorough investigation. New and innovative Intrusion Detection Systems (IDSs) have been proposed in the literature over the last years to address the protocol's security issues. In that regard, our survey paper: i) begins with extracting a set of design requirements for RPL-related IDSs based on discussing the diversity of attacks on the protocol and investigating their impact; ii) continues with identifying best practices and gaps in an IDS design which are derived by studying the evolution of the related bibliography (2013 − 2020); and iii) concludes with a number of guidelines extracted once we map the 22 IDSs under study to the attacks they encounter and compare them in line with the design requirements we introduce. Our analysis considers feedback from the corresponding authors for a deeper investigation.

IEEE Communications Magazine, 2019

Internet of Things (IoT) has evolved from an experimental to a backbone technology able to connec... more Internet of Things (IoT) has evolved from an experimental to a backbone technology able to connect myriads of people, things, and services for a large range of businesses. At the same time, the emergence of Software-Defined Networking (SDN) can ideally handle IoT challenges for elasticity, hetero-geneity, and mobility, offering an architecture that abstracts decision-making away from the data plane, and provides a programmable network facility. Along these lines, we propose MINOS, a multi-protocol SDN platform for IoT that implements service-awareness utilizing: (i) appropriate SDN abstractions and interfaces for logically-centralized network control of diverse and resource-constraint IoT environments; (ii) two network protocols that are deployable and configurable on-demand; and (iii) a Graphical User Interface (GUI) that provides a bespoke dashboard and a real-time visualization tool. Due to its components , MINOS enables: experimentation with novel network control features and protocols that realize optimized routing over heterogeneous IoT nodes; application of real-time strategies as a response to the dynamic network conditions; support of individual protocol configurations per node; and flexibility to accommodate new protocols and control algorithms. Our results demonstrate MINOS as an enabling platform for two protocols, the CORAL-SDN and the Adaptable-RPL, which, in comparison with the state-of-the-art IoT routing protocol RPL, improve the packet delivery ratio with relative small control overhead. 1

We propose the Multi-Access Edge Computing for Content and Measurements (MECOM) experimentation p... more We propose the Multi-Access Edge Computing for Content and Measurements (MECOM) experimentation platform which orchestrates cloud and network aspects for efficient content and IoT measurements' distribution to mobile users. MECOM brings together: (i) heterogeneous lightweight cloud technologies hosting the content and IoT data; (ii) multi-homing capabilities in the mobile nodes that select the best connectivity option for the service used, e.g., for low latency or high throughput; (iii) early content popularity change detection that scales the content distribution; and (iv) IoT routing protocol adjustments that reduce the delays of measurements' collection. Our proposal addresses diverse service requirements in two relevant scenarios, i.e., for content distribution and IoT services.

We present a showcase of our SDN-inspired facility for the Internet of Things (IoT)-the CORAL (Cr... more We present a showcase of our SDN-inspired facility for the Internet of Things (IoT)-the CORAL (Cross-Layer Control of Data Flows) infrastructure. CORAL provides a hierarchy of network controllers that monitor network behaviour and adapts network protocol parameters on demand. It is built on top of rich network control abstractions and is hardware-independent. Our facility offloads protocol functionality to the controllers, enabling intelligent IoT protocol adaptations. To demonstrate our solution, we focused on the IPv6 Routing Protocol for Low-Power and Lossy Networks (RPL). Although RPL is the state-of-the-art routing protocol for constrained devices and lossy networks, it is inefficient in mobile environments. We show a particular example where, using CORAL, we improve the Packet Delivery Ratio (PDR) in a dynamic IoT topology.

2009 Fifth International Conference on Wireless and Mobile Communications, 2009

The paper describes the necessary fields investigated for creating an application that is able to... more The paper describes the necessary fields investigated for creating an application that is able to monitor any kind of network, wired or wireless, with all its possible aspects. In the same application, we also implemented original algorithms for finding the position of a moving station, utilizing the signal level of the wireless protocols 802.11 devices (Wi-Fi). Field research and exhausting

Education and Information Technologies, 2015

ABSTRACT The tremendous popularity of mobile computing and Android in particular has attracted mi... more ABSTRACT The tremendous popularity of mobile computing and Android in particular has attracted millions of developers who see opportunities for building their own start-ups. As a consequence Computer Science students express an increasing interest into the related technology of Java development for Android applications. Android projects are complex by nature and relatively large software products while their development calls for the application of established software engineering practices and tools. However, most software engineering courses focus on ‘conventional’ software development for desktop or web applications. In this paper we report on the design, implementation and assessment of a novel short course aiming at bridging the gap between software engineering and Android development. The goal is to demonstrate the need for applying software engineering principles on Android development as well as to emphasize that writing software for mobile devices should be regarded as an equally serious programming activity. The proposed course covers design principles, patterns, metrics, refactorings and collaborative software development. The course has been delivered to three groups of undergraduate and postgraduate students at two different institutes. The course has been evaluated: a) by performing a student satisfaction survey, b) through summative assessment of students’ performance, c) by investigating whether the proposed course modified the students’ career interests and d) by employing assessment by peers based on rubrics. The results indicate that such a short course is capable of increasing student’s interest on Android development as well as their awareness of the importance of software engineering concepts on mobile application software development.

This is the 2 nd part of a study on the evaluation of the Web sites of companies in the GCC (Gulf... more This is the 2 nd part of a study on the evaluation of the Web sites of companies in the GCC (Gulf Council Countries) and attempts to answer the question of whether security and privacy but, also, accessibility and availability issues are addressed by the developers locally. A total number of 129 web sites from companies in Bahrain, Kuwait, Saudi Arabia, Qatar and United Arab Emirates were evaluated. The tables 3 and 4 (appendix), i.e. on accessibility/ availability and security/ privacy, from the WSEI (Web Site Evaluation Index) were applied during the evaluation. The results of the evaluation are not encouraging at all showing that security and privacy issues are not a priority when developing the web sites and accessibility and availability are not among their serious concern either.

Planning and Implementation, 2011

This paper intends to shed light on the security problems faced by e-learning software; which, u... more This paper intends to shed light on the security
problems faced by e-learning software; which, until now has not
been systematically tested for vulnerabilities and weaknesses.
These result to web programs exposed to attacks that are fairly
easy to implement. Additionally, e-learning software deals with
intelligent, studious individuals; The intended audience for the
product has the knowledge, or is potentially being taught the
knowledge, to compromise the software. The problem is that in a
situation like this, the compromised software remains
unrevealed, probably for ever, because the beneficiaries have
absolutely no need to reveal their findings, but rather exploit the
very best of it.

In this paper, field research was conducted in order to enrich and strengthen the “NetArgus” appl... more In this paper, field research was conducted in order to enrich and strengthen the “NetArgus” application that is
able to monitor either a wired or a wireless network with all its possible aspects. Original algorithms were
implemented in an effort to find the position of a moving station utilizing the signal level of wireless local area
network (WLAN) devices. Exhausting sampling and research were done, in order to resolve various practical
problems associated with the signal level of the wireless stations as well as the involved hardware. Various flaws
and omissions of 802.11x protocols were discovered, such as the lack of definition of the signal level and its
width range. Moreover, a plethora of positioning practical problems has been adequately managed. Hence, an
application was constructed to draw paths and manipulate proper information from various network moving
clients, using the Simple Network Management Protocol (SNMP) as well as low level operating system libraries.
Last but not least, “Kalman Filter” was implemented and fully tested in order to correct the positioning
unavoidable mistakes.

We may define e-voting as the process of evaluating an article or ranking a translation of a spec... more We may define e-voting as the process of evaluating an article or ranking a translation of a specific scientific term in a relevant web site. This all process of participation and interaction is one of the Web 2.0 definitions, the collaborative knowledge. On-line dictionaries have to consider this factor in order to succeed. They have to be interactive and they have to attract and support the users’ participation and contribution. In the proposed e-dictionary, namely “Wiki-Dic”, some experts begin a dictionary, they start filling it with words and translations, and all users are allowed not only to look for the translation, but also to vote for it. The most voted translations go to the top. In addition, appropriate security countermeasures are used to deal efficiently with the “one vote per person” problem and to avoid malicious software. Furthermore, an intelligent algorithm that is giving weights to the voters is implemented. In this way, the weights are computed automatically from our application, based on quantitative and
qualitative information as well.

2009 Fifth International …, Jan 1, 2009

E-voting is an election system that allows a voter to record his or her secure and secret ballot ... more E-voting is an election system that allows a voter to record his or her secure and secret ballot electronically. We can also
define as e-voting the process of evaluating an article or ranking a translation of a specific scientific term in a relevant
web site. This all process of participation and interaction is one of the Web 2.0 definitions, the collaborative knowledge.
An electronic (on-line) dictionary in order to succeed has to consider this factor. It has to be interactive and it has to
attract and support the users’ participation and contribution. Therefore, an e-voting system may confront properly these
issues. In the e-dictionary we propose here (“Wiki-Dic”), some experts begin a dictionary, they start filling it with words
and translations, and all users are allowed not only to look for the translation, but also to vote for it. The most voted
translations go to the top. Every minute the users may be informed for the most voted translation, as the most widely
accepted definition appears first in the row.

Future Generation Computer Systems, 2021

Internet of Things (IoT) constitutes a pivotal contributor to the Industry 4.0 (I 4.0) vision, te... more Internet of Things (IoT) constitutes a pivotal contributor to the Industry 4.0 (I 4.0) vision, technologically transforming production and societies. It enables novel services through the seamless integration of devices, such as motes carrying sensors, with the Internet. However, the broad adoption of IoT technologies is facing security issues due to the direct access to the devices from the Internet, the broadcasting nature of the wireless media, and the potential unattended operation of relevant deployments. In particular, the Routing over Low Power and Lossy Networks (RPL) protocol, a prominent IoT solution, is vulnerable to a large number of attacks, both of general-purpose and RPL-specific nature, while the resource-constraints of the corresponding devices are making attack mitigation even more challenging, e.g., in terms of involved control overhead and detection accuracy. In this paper, we introduce ASSET, a novel Intrusion Detection System (IDS) for RPL with diverse profiles to tackle the above issues that mitigate at least 13 attacks. At the same time, other solutions go up to eight. ASSET, inspired by the network softwarization paradigm, supports a novel, extendable workflow, bringing together three anomaly-detection and four RPL specification-based mechanisms, a novel attacker identification process, as well as multiple attack mitigation strategies. Our IDS also supports an adaptable control & monitoring protocol, trading overhead for accuracy, depending on the network conditions. The proof-ofconcept experiments show that ASSET entails a low overhead for the different modes of operation it supports (i.e., 6.28 percent on average) compared to other solutions reaching up to 30 percent. At the same time, it also keeps the power consumption at acceptable levels (from 0.18 up to 1.54 percent more). Moreover, it provides 100 percent accuracy for specific attacks and can identify the attacker in far more attacks than any other similar solution.

Elsevier Computers & Security, 2021

Internet of Things (IoT) is an emerging technology that has seen remarkable blossom over the last... more Internet of Things (IoT) is an emerging technology that has seen remarkable blossom over the last years. The growing interest for IPv6 constrained networks has made the Routing Protocol for Low Power and Lossy Networks (RPL) the standard routing solution, which has gained significant attention and maturity in the literature. However, due to the networks' open and possibly unattended environment of operation, as well as to the nodes' constraints, the security of the protocol is a challenging issue, currently under thorough investigation. New and innovative Intrusion Detection Systems (IDSs) have been proposed in the literature over the last years to address the protocol's security issues. In that regard, our survey paper: i) begins with extracting a set of design requirements for RPL-related IDSs based on discussing the diversity of attacks on the protocol and investigating their impact; ii) continues with identifying best practices and gaps in an IDS design which are derived by studying the evolution of the related bibliography (2013 − 2020); and iii) concludes with a number of guidelines extracted once we map the 22 IDSs under study to the attacks they encounter and compare them in line with the design requirements we introduce. Our analysis considers feedback from the corresponding authors for a deeper investigation.

IEEE Communications Magazine, 2019

Internet of Things (IoT) has evolved from an experimental to a backbone technology able to connec... more Internet of Things (IoT) has evolved from an experimental to a backbone technology able to connect myriads of people, things, and services for a large range of businesses. At the same time, the emergence of Software-Defined Networking (SDN) can ideally handle IoT challenges for elasticity, hetero-geneity, and mobility, offering an architecture that abstracts decision-making away from the data plane, and provides a programmable network facility. Along these lines, we propose MINOS, a multi-protocol SDN platform for IoT that implements service-awareness utilizing: (i) appropriate SDN abstractions and interfaces for logically-centralized network control of diverse and resource-constraint IoT environments; (ii) two network protocols that are deployable and configurable on-demand; and (iii) a Graphical User Interface (GUI) that provides a bespoke dashboard and a real-time visualization tool. Due to its components , MINOS enables: experimentation with novel network control features and protocols that realize optimized routing over heterogeneous IoT nodes; application of real-time strategies as a response to the dynamic network conditions; support of individual protocol configurations per node; and flexibility to accommodate new protocols and control algorithms. Our results demonstrate MINOS as an enabling platform for two protocols, the CORAL-SDN and the Adaptable-RPL, which, in comparison with the state-of-the-art IoT routing protocol RPL, improve the packet delivery ratio with relative small control overhead. 1

We propose the Multi-Access Edge Computing for Content and Measurements (MECOM) experimentation p... more We propose the Multi-Access Edge Computing for Content and Measurements (MECOM) experimentation platform which orchestrates cloud and network aspects for efficient content and IoT measurements' distribution to mobile users. MECOM brings together: (i) heterogeneous lightweight cloud technologies hosting the content and IoT data; (ii) multi-homing capabilities in the mobile nodes that select the best connectivity option for the service used, e.g., for low latency or high throughput; (iii) early content popularity change detection that scales the content distribution; and (iv) IoT routing protocol adjustments that reduce the delays of measurements' collection. Our proposal addresses diverse service requirements in two relevant scenarios, i.e., for content distribution and IoT services.

We present a showcase of our SDN-inspired facility for the Internet of Things (IoT)-the CORAL (Cr... more We present a showcase of our SDN-inspired facility for the Internet of Things (IoT)-the CORAL (Cross-Layer Control of Data Flows) infrastructure. CORAL provides a hierarchy of network controllers that monitor network behaviour and adapts network protocol parameters on demand. It is built on top of rich network control abstractions and is hardware-independent. Our facility offloads protocol functionality to the controllers, enabling intelligent IoT protocol adaptations. To demonstrate our solution, we focused on the IPv6 Routing Protocol for Low-Power and Lossy Networks (RPL). Although RPL is the state-of-the-art routing protocol for constrained devices and lossy networks, it is inefficient in mobile environments. We show a particular example where, using CORAL, we improve the Packet Delivery Ratio (PDR) in a dynamic IoT topology.

2009 Fifth International Conference on Wireless and Mobile Communications, 2009

The paper describes the necessary fields investigated for creating an application that is able to... more The paper describes the necessary fields investigated for creating an application that is able to monitor any kind of network, wired or wireless, with all its possible aspects. In the same application, we also implemented original algorithms for finding the position of a moving station, utilizing the signal level of the wireless protocols 802.11 devices (Wi-Fi). Field research and exhausting

Education and Information Technologies, 2015

ABSTRACT The tremendous popularity of mobile computing and Android in particular has attracted mi... more ABSTRACT The tremendous popularity of mobile computing and Android in particular has attracted millions of developers who see opportunities for building their own start-ups. As a consequence Computer Science students express an increasing interest into the related technology of Java development for Android applications. Android projects are complex by nature and relatively large software products while their development calls for the application of established software engineering practices and tools. However, most software engineering courses focus on ‘conventional’ software development for desktop or web applications. In this paper we report on the design, implementation and assessment of a novel short course aiming at bridging the gap between software engineering and Android development. The goal is to demonstrate the need for applying software engineering principles on Android development as well as to emphasize that writing software for mobile devices should be regarded as an equally serious programming activity. The proposed course covers design principles, patterns, metrics, refactorings and collaborative software development. The course has been delivered to three groups of undergraduate and postgraduate students at two different institutes. The course has been evaluated: a) by performing a student satisfaction survey, b) through summative assessment of students’ performance, c) by investigating whether the proposed course modified the students’ career interests and d) by employing assessment by peers based on rubrics. The results indicate that such a short course is capable of increasing student’s interest on Android development as well as their awareness of the importance of software engineering concepts on mobile application software development.

This is the 2 nd part of a study on the evaluation of the Web sites of companies in the GCC (Gulf... more This is the 2 nd part of a study on the evaluation of the Web sites of companies in the GCC (Gulf Council Countries) and attempts to answer the question of whether security and privacy but, also, accessibility and availability issues are addressed by the developers locally. A total number of 129 web sites from companies in Bahrain, Kuwait, Saudi Arabia, Qatar and United Arab Emirates were evaluated. The tables 3 and 4 (appendix), i.e. on accessibility/ availability and security/ privacy, from the WSEI (Web Site Evaluation Index) were applied during the evaluation. The results of the evaluation are not encouraging at all showing that security and privacy issues are not a priority when developing the web sites and accessibility and availability are not among their serious concern either.

Planning and Implementation, 2011

This paper intends to shed light on the security problems faced by e-learning software; which, u... more This paper intends to shed light on the security
problems faced by e-learning software; which, until now has not
been systematically tested for vulnerabilities and weaknesses.
These result to web programs exposed to attacks that are fairly
easy to implement. Additionally, e-learning software deals with
intelligent, studious individuals; The intended audience for the
product has the knowledge, or is potentially being taught the
knowledge, to compromise the software. The problem is that in a
situation like this, the compromised software remains
unrevealed, probably for ever, because the beneficiaries have
absolutely no need to reveal their findings, but rather exploit the
very best of it.

In this paper, field research was conducted in order to enrich and strengthen the “NetArgus” appl... more In this paper, field research was conducted in order to enrich and strengthen the “NetArgus” application that is
able to monitor either a wired or a wireless network with all its possible aspects. Original algorithms were
implemented in an effort to find the position of a moving station utilizing the signal level of wireless local area
network (WLAN) devices. Exhausting sampling and research were done, in order to resolve various practical
problems associated with the signal level of the wireless stations as well as the involved hardware. Various flaws
and omissions of 802.11x protocols were discovered, such as the lack of definition of the signal level and its
width range. Moreover, a plethora of positioning practical problems has been adequately managed. Hence, an
application was constructed to draw paths and manipulate proper information from various network moving
clients, using the Simple Network Management Protocol (SNMP) as well as low level operating system libraries.
Last but not least, “Kalman Filter” was implemented and fully tested in order to correct the positioning
unavoidable mistakes.

We may define e-voting as the process of evaluating an article or ranking a translation of a spec... more We may define e-voting as the process of evaluating an article or ranking a translation of a specific scientific term in a relevant web site. This all process of participation and interaction is one of the Web 2.0 definitions, the collaborative knowledge. On-line dictionaries have to consider this factor in order to succeed. They have to be interactive and they have to attract and support the users’ participation and contribution. In the proposed e-dictionary, namely “Wiki-Dic”, some experts begin a dictionary, they start filling it with words and translations, and all users are allowed not only to look for the translation, but also to vote for it. The most voted translations go to the top. In addition, appropriate security countermeasures are used to deal efficiently with the “one vote per person” problem and to avoid malicious software. Furthermore, an intelligent algorithm that is giving weights to the voters is implemented. In this way, the weights are computed automatically from our application, based on quantitative and
qualitative information as well.

2009 Fifth International …, Jan 1, 2009

E-voting is an election system that allows a voter to record his or her secure and secret ballot ... more E-voting is an election system that allows a voter to record his or her secure and secret ballot electronically. We can also
define as e-voting the process of evaluating an article or ranking a translation of a specific scientific term in a relevant
web site. This all process of participation and interaction is one of the Web 2.0 definitions, the collaborative knowledge.
An electronic (on-line) dictionary in order to succeed has to consider this factor. It has to be interactive and it has to
attract and support the users’ participation and contribution. Therefore, an e-voting system may confront properly these
issues. In the e-dictionary we propose here (“Wiki-Dic”), some experts begin a dictionary, they start filling it with words
and translations, and all users are allowed not only to look for the translation, but also to vote for it. The most voted
translations go to the top. Every minute the users may be informed for the most voted translation, as the most widely
accepted definition appears first in the row.