1,720,958 research outputs found
TinyKey: A light-weight architecture for wireless sensor networks securing real-world applications
No full textWhile sharing some commonalities with a canonical computer network, Wireless Sensor Network (WSN) presents many aspects which are unique. Security mechanisms in a WSN are mainly devoted to protect both the resources from attacks and misbehavior of nodes and the information transferred throughout the network itself. While the vast majority of the works on security for WSN in literature are focusing on novel mechanisms or performance evaluation in “protected” environment like simulators or dedicated WSN testbeds, to the best of our knowledge there are no existing works describing the performance of security mechanisms in operational WSN dealing with real-world applications. In this paper, we present TinyKey, a security architecture for WSNs that takes into account pragmatic concerns of a real-work deployment. For instance, most of the approaches in literature have neglected mechanisms related to key management. TinyKey comes with an integrated key management system that can be used in any deployment. We have developed TinyKey to satisfy the security requirements of two projects funded by the local government of the Trento province in Italy that aim at developing and deploying real-world applications based on WSNs. One project aims at improving the safety of the road tunnels around the city of Trento while the second project focuses on improving the quality of life of elderly people. As a result, we have been able to measure the performances of TinyKey in real deployments
Generalizing virtual network topologies in OpenFlow-based networks
No full textNetwork Virtualization (NV) is one of the most promising technique to enable innovation in today's network. A recent approach toward NV has been proposed through FlowVisor, whose aim is to leverage on the specific features of an OpenFlow-controlled network to share the same hardware forwarding plane among multiple logical networks. However, FlowVisor lacks some features to enable a full implementation of a NV architecture: the virtual topologies that can be established are restricted to subsets of the physical topology and it has no way for two slices to share flowspace and simultaneously prevent them from interfering with each other's traffic. In this work, an innovative system called ADVisor (ADvanced FlowVisor) which enhances FlowVisor while overcoming its major constraints is presented and a set of experimental results discussed to demonstrate its capability to provide an effective support toward a Network Virtualization architecture
Demonstrating generalized virtual topologies in an openflow network
No full textNetwork Virtualization (NV) is one of the most promising
approaches to enable innovation in today’s network. Generally
speaking, NV refers to the possibility of pooling together
low–level hardware and software resources belonging
to a networked system into a single administrative entity. In
such a way network resources could be effectively shared in
a transparent way among different logical network instances
corresponding to different virtual network topologies.
A recent approach toward Network Virtualization has been
proposed through FlowVisor [1], whose aim is to leverage on
the specific features of an OpenFlow–controlled network [2]
to share the same hardware forwarding plane among multiple
logical networks
AiroLAB: A framework toward effective virtualisation of multi-hop wireless networks
No full textIn this work, we introduce AiroLAB, a novel network virtualisation framework specifically tailored to multi-hop wireless networks. AiroLAB departs from conventional network virtualisation approaches by focusing on embedded, resource-constrained devices and by aiming at providing Wireless Internet Service Providers with an effective virtualisation mechanism where network resources are shared between production traffic and a variable number of experimental slices allowing novel solutions and services to be tested in a controlled yet realistic environment. In the paper, the design choices at the hearth of AiroLAB are presented, together with an early-stage prototype implementation and experimental results obtained in a small-scale wireless network testbed
Progressive virtual topology embedding in OpenFlow networks
No full textFuture internet would provide a flexible and simpler architectural design by combining novel low level clean-slate techniques such as OpenFlow with high level design principles such as network virtualization. However, previous research outlined that at the core of network virtualization stands a new set of challenges for network resources allocation. In this work we focus on one such challenge, namely the problem of virtual topology embedding. In this context users need to leverage the infrastructure substrate by accomodating logical topologies with high degree of flexibility. The network provider, on the other hand, aims at maximizing its revenue in term of size and number of topologies accepted while minimizing costs accounting for the substrate network resources used. To this aim, we present VT-Planner a novel virtual network embedding technique with reduced computational cost and very efficient over substrate topologies encountered in practice. Extensive numerical simulations are provided comparing this technique with state- of-the-art solutions: our results show that VT-Planner is able to achieve a good balance in terms of complexity and performance
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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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