Evaluation of a blockchain-enabled resource management mechanism for NGNs

A new era in ICT has begun with the evolution of Next Generation Networks (NGNs) and the development of human-centric applications. Ultra-low latency, high throughput, and high availability are a few of the main characteristics of modern networks. Network Providers (NPs) are responsible for the development and maintenance of network infrastructures ready to support the most demanding applications that should be available not only in urban areas but in every corner of the earth. The NPs must collaborate to offer high-quality services and keep their overall cost low. The collaboration among competitive entities can in principle be regulated by a trusted 3rd party or by a distributed approach/technology which can guarantee integrity, security, and trust. This paper examines the use of blockchain technology for resource management and negotiation among NPs and presents the results of experiments conducted in a dedicated real testbed. The implementation of the resource management mechanism is described in a Smart Contract (SC) and the testbeds use the Raft and the IBFT consensus mechanisms respectively. The goal of this paper is two-fold: to assess its performance in terms of transaction throughput and latency so that we can assess the granularity at which this solution can operate (e.g. support resource re-allocation among NPs on micro-service level or not) and define implementation-specific parameters like the consensus mechanism that is the most suitable for this use case based on performance metrics

Investigation of Information Dissemination Design Criteria in Large-scale Network Environments

Abstract-The design of efficient information dissemination mechanism is a challenging problem in large-scale network with respect to the number of messages and termination time. In this paper, advertisement and searching -the two basic ingredients of information dissemination -are investigated and certain criteria are proposed with respect to the correctness, promptness and fairness of the approach. Based on the complementarity of both advertisement and searching, the aforementioned criteria can be satisfied under certain conditions, which form the baseline of design principles for efficient information dissemination, as analytically -also using numerical results -is investigated here

Towards a blockchain-enabled crowdsourcing platform

Crowdsourcing has been pursued as a way to leverage the power of the crowd for many different purposes in diverse sectors from collecting information, aggregating funds, and gathering employees to perform tasks of different sizes among other targets. Data integrity and nonrepudiation are of utmost importance in these systems and are currently not guaranteed. Blockchain technology has been proven to improve on these aspects. In this article, we investigate the benefits that the adoption of Blockchain technology can bring in crowdsourcing systems. To this end, we provide examples of real-life crowdsourcing use cases and explore the benefits of using Blockchain, mainly as a database

On the successful deployment of community policing services: the TRILLION project case

The evolution of policing towards the next generation, not only involves confronting new types of crime such as cybercrime, but also the active engagement of citizens in the process of creating a secure environment through the deployment of community policing practices. However, in order to fully exploit the potential of community policing, the building of trust between citizens and Law Enforcement Officers is important. In this paper, the authors (all participating in the EU Research project on community policing TRILLION), discuss issues related to the use of innovative technologies, while ensuring societal approval, in the context of community policing. Both requirements and corresponding work leading to the actual implementation of a fully operational platform are presented

Unchaining Collective Intelligence for Science, Research and Technology Development by Blockchain-Boosted Community Participation

Since its launch just over a decade ago by the cryptocurrency Bitcoin, the distributed ledger technology (DLT) blockchain has followed a breathtaking trajectory into manifold application spaces. This paper analyses how key factors underpinning the success of this ground-breaking “internet of value” technology, such as staking of collateral (“skin in the game”), competitive crowdsourcing, crowdfunding, and prediction markets, can be applied to substantially innovate the legacy organization of science, research and technology development (RTD). Here, we elaborate a highly integrative, community-based strategy where a token-based crypto-economy supports finding best possible consensus, trust and truth through adding unconventional elements known from reputation systems, betting, secondary markets and social networking. These tokens support the holder’s formalized reputation, and are used in liquid-democracy style governance and arbitration within projects or community-driven initiatives. This participatory research model serves as a solid basis for comprehensively leveraging collective intelligence by effectively incentivizing contributions from the crowd, such as intellectual property (IP), work, validation, assessment, infrastructure, education, assessment, governance, publication, and promotion of projects. On the analogy of its current blockbusters like peer-to-peer structured decentralized finance (“DeFi”), blockchain technology can seminally enhance the efficiency of science and RTD initiatives, even permitting to fully stage operations as a chiefless Decentralised Autonomous Organization (DAOs)

Study and Design of algorithms for Information dissemination in unstructured environments

The focus of this thesis lies on the study of several existed techniques for information dissemination and on the introduction of new ones for application in the demanding environment of an unstructured network. Unstructured networks are the networks which because of their large scale, their scalability properties and their highly dynamic nature make it almost impossible for a node to possess accurate information, on any given time, regarding the overall network topology. One of the techniques studied here is the probabilistic flooding approach, especially its application on a random graph topology. Especially, by using two different, carefully selected random graphs it is possible to find the asymmetric bounds for the forwarding probability (pf) for an information message. This bounds will allow the probabilistic flooding network to successfully cover an underlying connected random graph G(N,p) by generating the minimum number of information dissemination messages. On top of it, it was proved both analytically and with simulations, that the use of probabilistic flooding in a connected random graph can succeed in reducing the generated number of disseminated messages, especially when this number is compared to the relative number produced by applying full flooding. Furthermore, the technique of Multiple Random Walkers was covered and analytical expressions regarding the coverage achieved for a fully connected topology were presented. For the study of less dense topologies, an ineffective coverage performance, at the early time slots, was expected and verified. This observation takes place because of the collection of a significant number of walkers near the initiator node, that need some time before managing to reach wider networking areas and, thus, to cover newly discovered nodes. As a solution to this phenomenon, the introduction of a new technique that is based on the replication of the walkers (each walker generates a replica of itself at each successful replication) during their move in the network and not from the beginning at the same (initiator) node. Simulation results proved that this technique shows a better performance for coverage. Finally, the performance of another replication technique, called the Randomly Replicated Random Walkers (RRRW), is studied in several networking topologies regarding the number of nodes that are covered along with the stretching of the information that is achieved. It was proved, via simulations, that the RRRW technique, in topologies that have a sense of a topological coverage of the network, can fill the performance gap between the full flooding and the single random walker approach.Στα πλαίσια της παρούσας διδακτορικής διατριβής ερευνώνται διάφορες υπάρχουσες τεχνικές για διάδοση πληροφορίας και προτείνονται ορισμένες νέες, για εφαρμογή στο περιβάλλον των μη δομημένων δικτύων. Μη Δομημένα ονομάζονται τα δίκτυα εκείνα, τα οποία λόγω του μεγάλου τους μέγεθος, της κατανεμημένης λειτουργίας τους και της μεγάλης δυναμική τους, καθιστούν αδύνατο για έναν κόμβο να έχει πλήρη γνώση ολόκληρης της τοπολογίας του δικτύου κάθε χρονική στιγμή. Η πρώτη τεχνική που μελετήθηκε ήταν αυτή της πιθανολογικής πλημμύρας. (probabilistic flooding) και η εφαρμογή της σε τυχαίους γράφους. Με τη βοήθεια δύο βοηθητικών τυχαίων γράφων μελετήθηκαν και βρέθηκαν τα ασυμπτωτικά όρια στα οποία πρέπει να βρίσκεται η τιμή της πιθανότητας προώθησης pf (ενός μηνύματος) έτσι ώστε το δίκτυο της πιθανολογικής πλημμύρας να επιτυγχάνει ολική κάλυψη του υφισταμένου συνδεδεμένου τυχαίου γράφου G(N,p) με το μικρότερο δυνατό αριθμό παραγόμενων μηνυμάτων. Επιπλέον αποδείχτηκε πως η εφαρμογή της εν λόγω τεχνικής, σε έναν τυχαίο γράφο, μπορεί να επιτύχει μείωση του παραγόμενου αριθμού μηνυμάτων σε σύγκριση με την τεχνική της πιθανολογικής πλημμύρας. Κατόπιν μελετήθηκε η τεχνική των πολλαπλών ταυτόχρονων δρομέων (Multiple Random Walkers) και παρουσιάστηκαν αναλυτικές εκφράσεις για την κάλυψη που επιτυγχάνεται στην περίπτωση ενός πλήρους γράφου. Κατά τη μελέτη της απόδοσης, ως προς την κάλυψη, σε λιγότερο πυκνές τοπολογίες παρατηρήθηκε μια μικρή χρονική περίοδος στα πρώτα βήματα όπου η κάλυψη που επιτυγχάνεται δεν είναι αποδοτική. Το φαινόμενο οφείλεται στη συσσώρευση στον εναρκτήριο κόμβο ενός μεγάλου αριθμού δρομέων (σύμφωνα με την τεχνική των MRW) οι οποίοι χρειάζονται λίγο χρόνο μέχρι να σταματήσουν να επισκέπτονται επικαλυπτόμενες περιοχές του δικτύου και να καλύπτουν καινούργιους κόμβους. Για την αντιμετώπιση του φαινομένου αυτού προτάθηκε μια τεχνική με την οποία οι τυχαίοι δρομείς αναπαράγονται κατά τη διάρκεια της κίνησης τους μέσα στο δίκτυο και αποφεύγεται η εξαρχής συγκέντρωσης τους σε έναν κόμβο. Τα αποτελέσματα των προσομοιώσεων επιβεβαίωσαν την αποδοτικότερη κάλυψη που επιτυγχάνεται με την τεχνική αυτή. Στη συνέχεια μελετήθηκε η απόδοση της τεχνικής των τυχαίων αναπαραγωγών ως προς τον αριθμό των κόμβων που επισκέπτεται και τη διάταση της πληροφορίας που επιτυγχάνει σε διάφορες τοπολογίες δικτύων. Αποδείχτηκε ότι σε τοπολογίες οι οποίες καταφέρνουν να επιδείξουν την έννοια της γεωγραφικής απόστασης των κόμβων η απόδοση της τεχνικής των τυχαίων αναπαραγωγών μπορεί να καλύψει το κενό ανάμεσα στην απόδοση της τεχνικής της ολικής πλημμύρας και αυτής του μοναδικού τυχαίου δρομέα

Energy cluster analysis based on consumption data in different weather condition

The main aim of this effort is the discovery of knowledge from data, concerning consumption of electric energy, during the year 2022, based on unattended learning methods. These data were collected from the Public Electricity Company of Kavala and the methods used are, at first the Factor analysis and second the K-means clustering algorithm. The overhead methodologies are realized by the use of Statistica Data Miner software