1,721,075 research outputs found
Toward Enabled Industrial Verticals in 5G: A Survey on MEC-Based Approaches to Provisioning and Flexibility
No full textThe increasing number of heterogeneous devices connected to the Internet, together with tight 5G requirements have generated new challenges for designing network infrastructures. Industrial verticals such as automotive, smart city and eHealthcare (among others) need secure, low latency and reliable communications. To meet these stringent requirements, computing resources have to be moved closer to the user, from the core to the edge of the network. In this context, ETSI standardized Multi-Access Edge Computing (MEC). However, due to the cost of resources, MEC provisioning has to be carefully designed and evaluated. This survey firstly overviews standards, with particular emphasis on 5G and virtualization of network functions, then it addresses flexibility of MEC smart resource deployment and its migration capabilities. This survey explores how the MEC is used and how it will enable industrial verticals
Streaming for vehicular users via elastic proxy buffer management
No full textIn this article we refer to the market of vehicular networks, where groups of customers located in the same public vehicle (e.g., a train or bus) connect to a terrestrial network through a wireless/satellite backbone link. Elastic buffering is a proxy management technique devised to decouple the multimedia information retrieval rate on the network backbone from the play out streaming rate at the user terminal. It has been shown in the past that the application of elastic buffering mechanisms in terrestrial networks brings significant advantages in terms of network effectiveness. We show that elastic buffering is an extremely effective means to reduce, or even eliminate, streaming service outage due to intermittent backbone connectivity, such as that occurring when a vehicle moves through tunnels. Moreover, we show that elastic buffering is not only a technique suitable for multimedia information retrieval services, but can be effectively applied to delayed real-time services
SQLR: Short-Term Memory Q-Learning for Elastic Provisioning
No full textAs a growing number of service and application providers choose cloud networks to deliver their services on a software-as-a-service (SaaS) basis, cloud providers need to make their provisioning systems agile enough to meet service level agreements (SLAs). At the same time, they should guard against over-provisioning, which limits their capacity to accommodate more tenants. To this end, we propose Shortterm memory Q-Learning pRovisioning (SQLR, pronounced as 'scaler'), a system employing a customized variant of the modelfree reinforcement learning algorithm. It can reuse contextual knowledge learned from one workload to optimize the number of virtual machines (resources) allocated to serve other workload patterns. With minimal overhead, SQLR achieves comparable results to systems where resources are unconstrained. Our experiments show that we can reduce the amount of provisioned resources by about 20% with less than 1% overall service unavailability (due to blocking), while delivering similar response times to those of an over-provisioned system
Adversarial Obstruction of Millimeter Wave Links
Full text linkWe use a stochastic geometry approach to study an adversarial attack to the physical layer of millimeter wave communications, which is extremely vulnerable to blockage due to obstructions. Previous investigations have applied stochastic geometry to the study of millimeter wave communication scenarios with randomly located obstructions, but in this paper we investigate what happens if some of them are actually due to a malicious attacker. It turns out that, with just few strategically positioned obstructions, an adversary can significantly hinder the millimeter wave link operation and cause extremely high outage probabilities. As expected, scenarios with multiple reflections are more robust against this kind of attack, since they can exploit the diversity of reflected paths, despite their lower quality. Conversely, millimeter wave communications without (or with limited) multipath diversity are shown to be extremely fragile. We also investigate the impact on blockage of different parameters of the obstructions, including their number, shape, and size. Finally, we elaborate the applications of our findings to identify countermeasures against this attack
Infrastructureless Pervasive Information Sharing with COTS Devices and Software
No full textInformation sharing is becoming a relevant issue for mobile broadband operators, due to the increasing popularity of social networks, to the increasing volumes of shared information, and to the steady increase in the number and capabilities of mobile devices connected to the Internet. Offloading information sharing services from the cellular infrastructure to device-to-device (D2D) communications can offer a welcome reduction of traffic. This paper discusses experiments with a smartphone information sharing application that can be used on commercial-off-the-shelf devices, with no need to root the device's software. In order to avoid unrealistic assumptions on the behavior of D2D communications, this work includes and builds upon the implementation of an Android application that supports infras-tructureless distributed content sharing among wireless devices using Wi-Fi Direct. The collected experimental data permit a detailed analysis of the occurring events, and a careful assessment of the performance of pervasive information sharing services. Our experiments reveal that many assumptions commonly used in the literature do not hold in real settings. We conclude that delay-tolerant services can be supported, albeit we also show that high densities of devices can (somewhat counter-intuitively) impair performance
Edge Gaming: A Greening Perspective
No full textWe tackle the problem of how to support gaming at the edge of the cellular network. The reduced latency and higher bandwidth that the edge enjoys with respect to cloud-based solutions implies that transferring cloud-based games to the edge could be a premium service for end-users. The goal of this work is to design a scheme compatible with MEC and network slicing principles of 5G and beyond, and which maximizes the utility of a service/infrastructure provider with time-varying edge node capacities due to the access to intermittent renewable energy. We formulate a multi-dimensional integer linear programming problem, proving that it is NP-hard in the strong sense. We prove that our problem is sub-modular and propose an efficient heuristic, GREENING, which considers the allocation of gaming sessions and their migration. For the mentioned scenario, we analyze a wide variety of realistic configurations at the edge, studying how the performance depends on (i) whether the games have a static or dynamic workload, (ii) the distribution of renewable energy through nodes and time, or (iii) the topology of the edge network. Through simulations, we show that our heuristic achieves performance close to that achieved by solving the NP-hard optimization problem, except with extremely lower complexity, and performs up to 25% better than state-of-the-art algorithms
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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