The impact of video transcoding parameters on event detection for surveillance systems

The process of transcoding videos apart from being computationally intensive, can also be a rather complex procedure. The complexity refers to the choice of appropriate parameters for the transcoding engine, with the aim of decreasing video sizes, transcoding times and network bandwidth without degrading video quality beyond some threshold that event detectors lose their accuracy. This paper explains the need for transcoding, and then studies different video quality metrics. Commonly used algorithms for motion and person detection are briefly described, with emphasis in investigating the optimum transcoding configuration parameters. The analysis of the experimental results reveals that the existing video quality metrics are not suitable for automated systems, and that the detection of persons is affected by the reduction of bit rate and resolution, while motion detection is more sensitive to frame rate

System architecture and deployment scenarios for SESAME: small cEllS coordinAtion for Multi-tenancy and Edge services

The surge of the Internet traffic with exabytes of data flowing over operators’ mobile networks has created the need to rethink the paradigms behind the design of the mobile network architecture. The inadequacy of the 4G UMTS Long term Evolution (LTE) and even of its advanced version LTE-A is evident, considering that the traffic will be extremely heterogeneous in the near future and ranging from 4K resolution TV to machine-type communications. To keep up with these changes, academia, industries and EU institutions have now engaged in the quest for new 5G technology. In this paper we present the innovative system design, concepts and visions developed by the 5G PPP H2020 project SESAME (Small cEllS coordinAtion for Multi-tenancy and Edge services). The innovation of SESAME is manifold: i) combine the key 5G small cells with cloud technology, ii) promote and develop the concept of Small Cells-as-a-Service (SCaaS), iii) bring computing and storage power at the mobile network edge through the development of non-x86 ARM technology enabled micro-servers, and iv) address a large number of scenarios and use cases applying mobile edge computing

Introducing mobile edge computing capabilities through distributed 5G Cloud Enabled Small Cells

Current trends in broadband mobile networks are addressed towards the placement of different capabilities at the edge of the mobile network in a centralised way. On one hand, the split of the eNB between baseband processing units and remote radio headers makes it possible to process some of the protocols in centralised premises, likely with virtualised resources. On the other hand, mobile edge computing makes use of processing and storage capabilities close to the air interface in order to deploy optimised services with minimum delay. The confluence of both trends is a hot topic in the definition of future 5G networks. The full centralisation of both technologies in cloud data centres imposes stringent requirements to the fronthaul connections in terms of throughput and latency. Therefore, all those cells with limited network access would not be able to offer these types of services. This paper proposes a solution for these cases, based on the placement of processing and storage capabilities close to the remote units, which is especially well suited for the deployment of clusters of small cells. The proposed cloud-enabled small cells include a highly efficient microserver with a limited set of virtualised resources offered to the cluster of small cells. As a result, a light data centre is created and commonly used for deploying centralised eNB and mobile edge computing functionalities. The paper covers the proposed architecture, with special focus on the integration of both aspects, and possible scenarios of application.Peer ReviewedPostprint (author's final draft

SAVASA project @ TRECVid 2013: semantic indexing and interactive surveillance event detection

In this paper we describe our participation in the semantic indexing (SIN) and interactive surveillance event detection (SED) tasks at TRECVid 2013 [11]. Our work was motivated by the goals of the EU SAVASA project (Standards-based Approach to Video Archive Search and Analysis) which supports search over multiple video archives. Our aims were: to assess a standard object detection methodology (SIN); evaluate contrasting runs in automatic event detection (SED) and deploy a distributed, cloud-based search interface for the interactive component of the SED task. Results from the SIN task, underlying retrospective classifiers for the surveillance event detection and a discussion of the contrasting aims of the SAVASA user interface compared with the TRECVid task requirements are presented

A cloud-enabled small cell architecture in 5G networks for broadcast/multicast services

© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.The evolution of 5G suggests that communication networks become sufficiently flexible to handle a wide variety of network services from various domains. The virtualization of small cells as envisaged by 5G, allows enhanced mobile edge computing capabilities, thus enabling network service deployment and management near the end user. This paper presents a cloud-enabled small cell architecture for 5G networks developed within the 5G-ESSENCE project. This paper also presents the conformity of the proposed architecture to the evolving 5G radio resource management architecture. Furthermore, it examines the inclusion of an edge enabler to support a variety of virtual network functions in 5G networks. Next, the improvement of specific key performance indicators in a public safety use case is evaluated. Finally, the performance of a 5G enabled evolved multimedia broadcast multicast services service is evaluated.Peer ReviewedPostprint (author's final draft

Technology pillars in the architecture of future 5G mobile networks: NFV, MEC and SDN

This paper analyzes current standardization situation of 5G and the role network softwarization plays in order to address the challenges the new generation of mobile networks must face. This paper surveys recent documentation from the main stakeholders to pick out the use cases, scenarios and emerging vertical sectors that will be enabled by 5G technologies, and to identify future high-level service requirements. Driven by those service requirements 5G systems will support diverse radio access technology scenarios, meet end-to-end user experienced requirements and provide capability of flexible network deployment and efficient operations. Then, based on the identified requirements, the paper overviews the main 5G technology trends and design principles to address them. In particular, the paper emphasizes the role played by three main technologies, namely SDN, NFV and MEC, and analyzes the main open issues of these technologies in relation to 5G.Preprin

Effective capacity theory for modeling systems with-varying servers, with an application to IEEE 802.11 WLANs

Many demanding network applications rely on stochastic Quality of Service (QoS) guarantees. The provision of such guarantees has motivated the application of the theory of Effective Bandwidth and Effective Capacity to the calculation and enforcement of delay-related QoS. However, up to now this application has only been justified on the basis of heuristic arguments when the queue is served at a variable rate. The thesis fills this gap, by formally establishing that the Effective Bandwidth/Capacity theory may be applied for asymptotically correct calculation and/or enforcement of delay tail-probabilities in systems with variable rate servers. In particular, the heuristically suggested linkage between the exponential decay rates of the buffer content and delay probability tails through the server's Effective Capacity function is formally shown to apply. Due to the prevalence of wireless networking, systems with time-varying servers are becoming all the more important. Indeed, a wireless station can be regarded as a time-varying data server, due to rate fluctuations at the physical or at the medium access control layer. In this context, the thesis proceeds with an application of the general results to ΙEEE 802.11 WLANs. In doing so, the thesis first establishes that an IEEE 802.11 mobile station can be regarded as a Semi-Markovian data server of the On/Off type, with known distributions for the On and Off periods, and subsequently derives the Effective Capacity function of this On/Off server. The general results can then be used for computing buffer overflow and delay violation probabilities in IEEE 802.11 WLANs, and for employing simple traffic control policies to enforce related QoS guarantees. Finally, the thesis illustrates the usage of the Effective Capacity function of the IEEE 802.11 stations as a design tool: Towards this end, the form of the said function highlights certain parameters of the backoff window distributions, which, if appropriately tailored, may lead to higher Effective Capacity values, hence to better delay-related (or loss-related) performance.Πολλές απαιτητικές δικτυακές εφαρμογές επιζητούν στοχαστικές εγγυήσεις ποιότητας υπηρεσίας. Το γεγονός αυτό ώθησε στην εφαρμογή της θεωρίας του Ισοδύναμου Εύρους Ζώνης και της Ισοδύναμης Χωρητικότητας για τον υπολογισμό ή/και τη διασφάλιση χρονικών εγγυήσεων ποιότητας υπηρεσίας. Ωστόσο, μέχρι σήμερα αυτή η εφαρμογή σε συστήματα αναμονής με χρονικά μεταβαλλόμενο ρυθμό εξυπηρέτησης επικαλούνταν μόνο ευριστικά επιχειρήματα. Η παρούσα διατριβή καλύπτει αυτό το κενό, θεμελιώνοντας αυστηρά τη χρήση της θεωρίας του Ισοδύναμου Εύρους Ζώνης και της Ισοδύναμης Χωρητικότητας για τον ασυμπτωτικά ακριβή υπολογισμό ή/και τη διασφάλιση της πιθανότητας η καθυστέρηση να υπερβεί ένα δοσμένο κατώφλι σε συστήματα αναμονής με μεταβαλλόμενο ρυθμό εξυπηρέτησης. Ειδικότερα, η διατριβή αποδεικνύει αυστηρά την ευρέως χρησιμοποιούμενη ευριστική σχέση μεταξύ των εκθετικών ρυθμών φθίσης των πιθανοτήτων υπέρβασης του περιεχομένου ενός ταμιευτήρα και των πιθανοτήτων υπέρβασης της καθυστέρησης σε αυτόν. Η μελέτη των συστημάτων αναμονής με χρονικά μεταβαλλόμενους εξυπηρετητές καθίσταται ολοένα και πιο σημαντική στις μέρες μας, λόγω της εξάπλωσης της ασύρματης δικτύωσης. Ακολουθώντας αυτήν τη συλλογιστική, η διατριβή εφαρμόζει τα γενικά αποτελέσματα της θεωρίας του Ισοδύναμου Εύρους Ζώνης και της Ισοδύναμης Χωρητικότητας στο πρότυπο ασύρματης τοπικής δικτύωσης ΙΕΕΕ 802.11. Προς αυτήν την κατεύθυνση, η διατριβή αποδεικνύει ότι ένα τερματικό ΙΕΕΕ 802.11 μπορεί να μοντελοποιηθεί ως ένας Ημί-Μαρκοβιανός εξυπηρετητής δεδομένων του τύπου On/Off, με γνωστές κατανομές για τις περιόδους On και Off, και στη συνέχεια υπολογίζει τη συνάρτηση Ισοδύναμης Χωρητικότητας αυτού του εξυπηρετητή On/Off. Τα παραχθέντα γενικά αποτελέσματα χρησιμοποιούνται για την εκτίμηση της πιθανότητας υπερχείλισης του ταμιευτήρα MAC ΙΕΕΕ 802.11, καθώς και της πιθανότητας η καθυστέρηση σε αυτόν να παραβιάσει ένα δοσμένο χρονικό όριο. Τα γενικά αποτελέσματα επιπλέον οδηγούν στη δημιουργία απλών πολιτικών ελέγχου κίνησης, προκειμένου να επιβληθούν οι σχετικές εγγυήσεις ποιότητας υπηρεσίας. Τελειώνοντας, η διατριβή παρουσιάζει τη χρήση της συνάρτησης Ισοδύναμης Χωρητικότητας των τερματικών ΙΕΕΕ 802.11 ως εργαλείου σχεδιασμού: Η μορφή της εν λόγω συνάρτησης υποδεικνύει συγκεκριμένες παραμέτρους των κατανομών οπισθοχώρησης, οι οποίες, εάν τροποποιηθούν καταλλήλως, οδηγούν σε μεγαλύτερες τιμές Ισοδύναμης Χωρητικότητας. Συνεπώς, σε καλύτερη επίδοση καθυστέρησης και σε καλύτερη επίδοση απωλειών πακέτων