161,440 research outputs found
A framework for experimenting content caching and distribution in ICN over SDN
No full textInformation (or Content) Centric Networking (ICN or CCN) is a new logical and an architectural solution for networking. It originates from the consideration that people value the Internet for thecontent it contains and not for where this content comes from. In this work, we are referring to our ICN based architecture which is called CONET (COntent NETwork). The thesis work covers several aspects on expanding the proposed architecture and addressing the issue of its deployment starting from the current IP networks. Thie is still an open issue, and different approaches have been proposedin the past. The contributions of this work have been classified in the upcoming few major points. The first is the proposal of a solution to support ICN paradigm leveraging the SDN concepts. Our approach is specifically designed to support the ICN framework called CONET, however the underlying ideas and concepts are general and applicable to the ICN proposals which follow the basic mode of operation of CCN/NDN approach. We have implemented our solution combining and extending Open Source tools. In the time frame in which this work has been conceived and developed, the available OpenFlow testbeds and the Open Source tools werebased on OpenFlow 1.0 specification, therefore we had to design the solution and the experiment taking into account the features that were available on off-the-shelf OpenFlow equipment. We discuss also the realization of advanced caching policies like Tag Based Forwarding Filter (TBFF), Dynamic Tag Based Forwarding (DTBF) and FIX (P) over the designed architecture. Caching policies are needed to optimize the use of the resource, because it is not possible in general to cache of all the items. The second contribution of this work concerns the design and implementation of an open source environment for the emulation of the proposed solutions over OpenFlow distributed testbeds (OFELIA – like) and its adaptation for the single host emulation over Mininet. The emulation environment includes also a web GUI framework for the monitoring of the experiments, which is capable to monitor at run time the traffic and the cached items in the network, and to provide tools for evaluating the performance of the proposed solutions
Variations on the Author
Get PDF“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
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Larry O. Spencer, Conference Author Presentation
No full textGen. Larry O. Spencer, USAF (Ret.), author of Dark Horse: A Journey from the Horseshoe to the Pentago
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
Authigenic minerals from the Paola Ridge (southern Tyrrhenian Sea): Evidences of episodic methane seepage
No full textPaola Ridge, along the NW Calabrian margin (southern Tyrrhenian Sea), is one of the few reported deep sea sites of precipitation of authigenic carbonates in the Tyrrhenian Sea. Here, the changing composition of the seeping fluids and the dynamic nature of the seepage induced the precipitation of pyrite, siderite and other carbonate phases. The occurrence of this array of authigenic precipitates is thought to be related to fluctuation of the sulfate-methane transition zone (SMTZ). Concretions of authigenic minerals formed in the near sub-bottom sediments of the Paola Ridge were investigated for their geochemical and isotopic composition. These concretions were collected in an area characterized by the presence of two alleged mud volcanoes and three mud diapirs. The mud diapirs are dotted by pockmarks and dissected by normal faults, and are known for having been a site of fluid seepage for at least the past 40 kyrs. Present-day venting activity occurs alongside the two alleged mud volcanoes and is dominated by CO2-rich discharging fluids. This discover led us to question the hypothesis of the mud volcanoes and investigate the origin of the fluids in each different domed structure of the study area. In this study, we used stable isotopes (carbon and oxygen) of carbonates coupled with rare earth element (REE) composition of different carbonate and non-carbonate phases for tracing fluid composition and early diagenesis of authigenic precipitates. The analyses on authigenic precipitates were coupled with chemical investigation of venting gas and sea-water. Authigenic calcite/aragonite concretions, from surficial sediments on diapiric structures, have depleted 13C isotopic composition and slightly positive δ18O values. By contrast, siderite concretions, generally found within the first 6 m of sediments on the alleged mud volcanoes, yielded positive δ13C and δ18O values. The siderite REE pattern shows consistent LREE (light REE) fractionation, MREE (medium REE) enrichment and positive Gd and La anomalies. As shown by the REE distribution, the 13C-depleted composition and their association with chemosymbiotic fauna, calcite/aragonite precipitated at time of moderate to high methane flux close to the seafloor, under the influence of bottom seawater. Authigenic siderite, on the other hand, formed in the subseafloor, during periods of lower gas discharges under prolonged anoxic conditions within sediments in equilibrium with 13C-rich dissolved inorganic carbon (DIC) and 18O-rich water, likely related to methanogenesis and intermittent venting of deep-sourced CO2
A framework for experimenting ICN over SDN solutions using physical and virtual testbeds
No full textInformation Centric Networking (ICN) is a paradigm in which the network layer provides users with access to content by names, instead of providing communication channels between hosts. The ICN paradigm promises to offer a set of advantages with respect to existing (IP) networks for the support of the large majority of current traffic. In this paper, we consider the deployment of ICN by exploiting the Software Defined Networking (SDN) architecture. SDN is characterized by a logically centralized control plane and a well-defined separation between data and control planes. An SDN-enabled network facilitates the introduction of ICN functionality, without requiring a complex transition strategy and the re-deployment of new ICN capable hardware. More in details, in this paper we provide: i) a solution to support ICN by exploiting SDN, extending a previous work of ours; ii) design and implement an open reference environment to deploy and test the ICN over SDN solutions over local and distributed testbeds; iii) design and implementation of a set of Caching policies that leverage on the ICN over SDN approach; iv) performance evaluation of key aspects of the ICN over SDN architecture and of the designed caching policies. All the source code and the monitoring suite are publicly available. To the best of our knowledge, there are no other similar solutions available in Open Source, nor similar emulation platforms, including also a comprehensive set of monitoring tools
Rational diagnostic procedure for Zellweger syndrome (ZS) and other peroxisomal biogenesis defects (PBDS)
No full textRational diagnostic procedure for Zellweger syndrome (ZS) and other peroxisomal biogenesis defects (PBDS)
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