1,721,210 research outputs found
Quality of service in IP over WDM: Considering both service differentiation and transmission quality
No full textIP over WDM networks are a promising candidate for the next generation optical Internet networks. A new traffic-engineering (TE) scheme is proposed in this paper with the objective to route subwavelength connection requests with QoS constraints. In particular, we consider the routing of high-priority connections characterized by stringent requirements in term of delay and packet-loss ratio, by translating them into constraints at the physical layer. Furthermore, in order to provide efficient service differentiation, the impact of a suboptimal preemption algorithm is analyzed through extensive simulation experiments considering both the blocking probability and the network disruption, while comparing it with an optimal mechanism proposed in literature
Fake Truth. The Legal Issue of Archaeological Forgery
No full textArt forgery is a crime against public trust and it is frequently considered to be a violation of truth, intended as the correspondence between language and reality. Starting from the Buonarroti case, the author compares art forgery and fake artwork, which can have an effect of truth, and tries to explain the legal meaning of authentication, which requires a judicial procedure when the controversy of attribution is permanent. Examining the van Meegeren case, the author concludes the analysis with a critique of the correspondence theory of truth and with the proposal of a dialectical model for the authentication of works of art. Finally, considering the F words (forge, false, fake, fictional), it is asserted in the essay that, in today’s culture, fake artwork preserves the profound ambiguity of truth in fiction
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
Dynamic grooming in IP over optical networks based on the overlay architecture
No full textThis paper defines a formal framework for the definition of dynamic grooming policies in IP over optical networks. The formal framework is then specialized for the Overlay Architecture, where the control plane of the IP (Internet protocol) and optical levels are separated, and no information is shared between the two.
We define a family of grooming policies for the Overlay Architecture based on constraints on the number of hops and on the bandwidth sharing degree at the IP level, and we analyze the performances as a function of the grooming parameters in regular and irregular topologies.
Results are derived using realistic traffic models that depart from the circuit-like traffic traditionally used in grooming studies
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
Dynamic grooming in IP over WDM networks: A study with realistic traffic based on GANCLES simulation package
No full textDynamic grooming capabilities lies at the hearth of many envisaged scenarios for IP over Optical networks, but studies on its performance are still in their infancy. This work addresses two fundamental aspects of the problem. First of all it presents a novel tool for the study of IP over Optical networks. The tool, freely available on-line, is a network level simulator named GANCLES that includes several innovative features allowing the study of realistic scenarios in IP over Optical networking, making it an ideal tool for Traffic Engineering purposes. GANCLES architecture enables the simulation of dynamic traffic grooming on top of a realistic network model that correctly describes the logical interaction between the optical and the IP layer, i.e., the mutual relationship between routing algorithms and lightpath assignment procedures at the optical layer and routing at the IP layer. Adding or removing lightpaths changes the logical IP topology, which affects IP routing and traffic patterns. The simulator allows for the description of Overlay, Augmented or Peer IP over Optical architectures, depending on the amount of information shared between the IP and optical domain. Second it analyzes and discusses several performance indices and aspects of different grooming policies in the IPO Overlay model, using different traffic models, some of them including elasticity of best effort traffic. Both regular and mesh topologies are analyzed, and results clearly show that the correct evaluation of dynamic grooming policies in IPO networks requires a sophisticated level of modeling, since simplistic assumptions like Poisson traffic, or the incorrect representation of the interaction of IP and Optical control planes, may induce misleading results
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