Handling privacy and concurrency in an online educational evaluation system

Nowadays, all academic institutions exhibit and distribute their material over Internet. Moreover, e-learning and e-evaluation products is one of the most rapidly expanding areas of education and training, with nearly 30% of U.S. college and university students now taking at least one online course. However, Internet increases the vulnerability of digital educational content exploitation since it is a potential hostile environment for secure data management. The challenge is that providing current online educational tools that are accessible by a large number of users, these educational environments handle data of varying sensitivity thus it is increasingly important to reason about and enforce information privacy guarantees in the presence of concurrency. The present paper provides a privacy preserving approach in a concurrent online educational evaluation system. It introduces a privacy preserving approach for utilizing online concurrent evaluation of acquired student competencies that handles the increasingly complex issues of designing, developing and e-competence evaluation systems suitable for educational and e-learning environments. The proposed architecture for an online competence evaluation system offers access control and protect users' private data while, it provides concurrent procedures for evaluating competencies. © 2019 International Press of Boston, Inc. All rights reserved.European Commission, ECThis work has been partially supported by the “Implementation of Software Engineering Com-petence Remote Evaluation for Master Program Graduates (iSECRET)” project No 2015-1-LVo1-KA203-013439 funded by ERASMUS+ of the European Commission

On the existence of highly organized communities in networks of locally interacting agents

In this paper we investigate phenomena of spontaneous emergence or purposeful formation of highly organized structures in networks of related agents. We show that the formation of large organized structures requires exponentially large, in the size of the structures, networks. Our approach is based on Kolmogorov, or descriptional, complexity of networks viewed as finite size strings. We apply this approach to the study of the emergence or formation of simple organized, hierarchical, structures based on Sierpinski Graphs and we prove a Ramsey type theorem that bounds the number of vertices in Kolmogorov random graphs that contain Sierpinski Graphs as subgraphs. Moreover, we show that Sierpinski Graphs encompass close-knit relationships among their vertices that facilitate fast spread and learning of information when agents in their vertices are engaged in pairwise interactions modelled as two person games. Finally, we generalize our findings for any organized structure with succinct representations. Our work can be deployed, in particular, to study problems related to the security of networks by identifying conditions which enable or forbid the formation of sufficiently large insider subnetworks with malicious common goal to overtake the network or cause disruption of its operation

Challenges and Opportunities in Industry 4.0 for Mechatronics, Artificial Intelligence and Cybernetics

Industry 4.0 has risen as an integrated digital manufacturing environment, and it has created a novel research perspective that has thrust research to interdisciplinarity and exploitation of ICT advances. This work presents and discusses the main aspects of Industry 4.0 and how intelligence can be embedded in manufacturing to create the smart factory. It briefly describes the main components of Industry 4.0, and it focuses on the security challenges that the fully interconnected ecosystem of Industry 4.0 has to meet and the threats for each component. Preserving security has a crucial role in Industry 4.0, and it is vital for its existence, so the main research directions on how to ensure the confidentiality and integrity of the information shared among the Industry 4.0 components are presented. Another view is in light of the security issues that come as a result of enabling new technologies. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Acknowledgements. We thank Dawn Ernstzen, Division of Physiotherapy, Stellenbosch University, for her contextualisation work for chronic pain management in SA used in the example in this article, and Michelle Galloway for her support in finalising the submission on behalf of the author team. Funding. The authors were funded, partially or in full, by the SAGE project, a 3-year (2014 - 2017) Flagship Grant from the South African Medical Research Council. The Flagship Grant programme was not involved in the conceptualisation or conduct of this study

Evaluating the suitability of several AR devices and tools for industrial applications

In recent years, there has been an increasing interest in Industrial Augmented Reality (IAR) due to its prominent role in the ongoing revolution known as Industry 4.0. For companies and industries it is essential to evaluate carefully which of the developed AR-based technologies to adopt, and when, for tasks such as training, maintenance, assistance, and collaborative design. There is also a wide array of hardware and software alternatives on the market, characterized by a significant heterogeneity in terms of functionalities, performance and cost. With this work, our objective is to study and compare some widely available devices and Software Development Kits (SDKs) for AR by leveraging a set of evaluation criteria derived from the actual literature which have been deemed capable to qualify the above assets as suitable for industrial applications. Such criteria include the operative range, robustness, accuracy and stability. Both marker-based and marker-less solutions have been considered, in order to investigate a wide range of possible use cases

Ασφαλή και έμπιστα πρωτόκολλα επικοινωνιών με χρήση κρυπτογραφίας και κρυπτανάλυσης

In this PhD thesis, we try to use formal logic and threshold phenomena that asymptotically emerge with certainty in order to build new trust models and to evaluate the existing one. The departure point of our work is that dynamic, global computing systems are not amenable to a static viewpoint of the trust concept, no matter how this concept is formalized. We believe that trust should be a statistical, asymptotic concept to be studied in the limit as the system's components grow according to some growth rate. Thus, our main goal is to define trust as an emerging system property that “appears” or “disappears” when a set of properties hold, asymptotically with probability$0$ or $1$ correspondingly. Here we try to combine first and second order logic in order to analyze the trust measures of specific network models. Moreover we can use formal logic in order to determine whether generic reliability trust models provide a method for deriving trust between peers/entities as the network's components grow. Our approach can be used in a wide range of applications, such as monitoring the behavior of peers, providing a measure of trust between them, assessing the level of reliability of peers in a network. Wireless sensor networks are comprised of a vast number of ultra-small autonomous computing, communication and sensing devices, with restricted energy and computing capabilities that co-operate to accomplish a large sensing task. Sensor networks can be very useful in practice. Such systems should at least guarantee the confidentiality and integrity of the information reported to the controlling authorities regarding the realization of environmental events. Therefore, key establishment is critical for the protection in wireless sensor networks and the prevention of adversaries from attacking the network. Finally in this dissertation we also propose three distributed group key establishment protocols suitable for such energy constrained networks.Στην διδακτορική διατριβή αναπτύξαμε ασφαλή και έμπιστα πρωτόκολλα επικοινωνιών εισάγοντας ένα νέο μοντέλο έμπιστου συστήματος που ικανοποιεί τις συνεχώς εξελισσόμενες απαιτήσεις των υπολογιστικών συστημάτων. Για την ανάπτυξη του μοντέλου μας συνδυάσαμε την μαθηματική λογική και τα φαινόμενα κατωφλίου που προκύπτουν ασυμπτωτικά στην ανάπτυξη των συνδυαστικών δομών. Η βασική ιδέα της διδακτορικής διατριβής είναι ότι στα δυναμικά γενικά συστήματα υπολογισμού δεν μπορεί η έννοια της εμπιστοσύνης και της ασφάλειας να είναι στατική. Πιστεύουμε ότι ένα έμπιστο και ασφαλές σύστημα θα πρέπει να μελετάται με στατιστικές, ασυμπτωτικές παραμέτρους, καθώς τα τμήματα του συστήματος εξελίσσονται. Κατά συνέπεια, ο κύριος στόχος μας είναι να καθορίσουμε την εμπιστοσύνη ως μια ιδιότητα του συστήματος που «εμφανίζεται» όταν ισχύουν ασυμπτωτικά, σχεδόν βέβαια ένα σύνολο λογικών ιδιοτήτων στις τυχαίες δομές επικοινωνίας, οι οποίες διαμορφώνουν τα συστήματα υπολογισμού. Στην διδακτορική διατριβή καθορίζονται διάφορες ιδιότητες που σχετίζονται με την ασφάλεια και εμπιστοσύνη του συστήματος και εκφράζονται χρησιμοποιώντας την λογική πρώτης ή δεύτερης τάξης και ταυτόχρονα ορίζονται και οι προϋποθέσεις κάτω από τις οποίες αυτές οι ιδιότητες εμφανίζονται στο όριο τους, καθώς το σύστημα αυξάνεται. Στην παρούσα εργασία χρησιμοποιούμε μοντέλα γράφων που μπορούν ρεαλιστικά να περιγράψουν ένα δυναμικό και συνεχώς εξελισσόμενο δίκτυο και δείχνουμε ότι αυτά τα μοντέλα μπορεί να χρησιμοποιηθούν για να ικανοποιούν διάφορες “καλές” ιδιότητες, οι οποίες του επιτρέπουν μια ασφαλή επικοινωνία. Το τελευταίο διάστημα παρουσιάζουν αρκετό ερευνητικό και επιστημονικό ενδιαφέρον τα ασύρματά δίκτυα που χρησιμοποιούν συσκευές με μικρούς πόρους σε μνήμη και ενέργεια. Επιπλέον η διδακτορική διατριβή περιλαμβάνει τον σχεδιασμό και την υλοποίηση νέων κρυπτογραφικών πρωτοκόλλων διαχείρισης κλειδιού σε τέτοια ασύρματα δυναμικά δίκτυα. Εδώ παρουσιάζουμε κρυπτογραφικά πρωτόκολλα που είναι κατάλληλα για μια μη στατική δομή δικτύου, τα οποία δεν απαιτούν συγκεκριμένη τοπολογία δικτύου και στηρίζονται μόνο στις απλές περιορισμένου φάσματος ανταλλαγές μηνυμάτων. Για να μπορέσουμε να αναπτύξουμε αυτά τα πρωτόκολλα βασιστήκαμε σε γνωστές κρυπταναλυτικές μεθόδους χρησιμοποιώντας πρωτόκολλα κρυπτογράφησης και αποκρυπτογράφησης. Τέλος η μελέτη μας δίνει έμφαση στα πλεονεκτήματα και τα μειονεκτήματα των πρωτοκόλλων μας δεδομένης της διαθέσιμης τεχνολογίας, των αντίστοιχων κριτηρίων αποδοτικότητας (ενέργεια, χρόνος) και του παρεχόμενου επιπέδου ασφάλειας

A trusted architectural model for interconnecting testbeds of wireless sensor networks

Designing wireless sensor networks is inherently complex; many aspects such as energy efficiency, limited resources, decentralized collaboration, fault tolerance have to be tackled. To be effective and to produce applicable results, fundamental research has to be tested, at least as a proof-of-concept, in large scale environments, so as to assess the feasibility of the new concepts, verify their large scale effects (not only at technological level, but also as for their foreseeable implications on users, society and economy) and derive further requirements, orientations and inputs for the research. In this paper we focus on the problems of interconnecting existing testbed environments via the Internet and providing a virtual unifying laboratory that will support academia, research centers and industry in their research on networks and services. In such a facility important issues of trust, security, confidentiality and integrity of data may arise especially for commercial (or not) organizations. In this paper we investigate such issues and present the design of a secure and robust architectural model for interconnecting testbeds of wireless sensor networks

A security model for internet-based digital asset management systems

Usage and exploitation of the Internet is a critical requirement for managing and distributing valuable digital assets. This requirement introduces a great number of threats for commercial (or not) organizations that may cause huge data and financial losses, harm their reputation as well as people's trust on them. In this paper we present the research challenges for secure digital asset management over the web by proposing a model that provides data safety and secure user interaction on especially demanding on-line collaboration environments. © 2008 Springer-Verlag Berlin Heidelberg