1,721,014 research outputs found

    c © 2013 SCPE A SESSION INITIATION PROTOCOL FOR THE INTERNET OF THINGS ∗

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    Abstract. The Internet of Things (IoT) refers to the interconnection of billions of constrained devices, denoted as “smart objects”, in an Internet-like structure. Smart objects typically feature limited capabilities in terms of computation and memory and operate in constrained environments, such as low-power lossy networks. As the Internet Protocol (IP) has been foreseen as the standard for communications in IoT, an effort to bring IP connectivity to smart objects and define suitable communication protocols (i.e. Constrained Application Protocol (CoAP)) is being carried out within standardization organizations, such as the Internet Engineering Task Force (IETF). In this paper, we propose a constrained version of the Session Initiation Protocol (SIP), named “CoSIP”, whose intent is to allow constrained devices to instantiate communication sessions in a lightweight and standard fashion. Session instantiation can include a negotiation phase of some parameters which will be used for all subsequent communication. CoSIP can be adopted in several application scenarios, such as service discovery and publish/subscribe applications, which are detailed. An evaluation of the proposed protocol is also presented, based on a Java implementation of CoSIP, to show the benefits that its adoption can bring about, in terms of compression rate with the existing SIP protocol and message overhead compared with the use of CoAP

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The 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

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    “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

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    We 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

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    We 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

    Author Index

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    koamabayili/VECTRON-author-checklist: VECTRON author checklist

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    We have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used

    L.: CoSIP: a constrained session initiation protocol for the internet of things

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    Abstract. The Internet of Things (IoT) refers to the interconnection of billions of constrained devices, denoted as “smart objects ” (SO), in an Internet-like structure. SOs typically feature limited capabilities in terms of computation and memory and operate in constrained environments, such low-power lossy networks. As IP has been foreseen as the standard for smart-object communication, an e↵ort to bring IP connectivity to SOs and define suitable communication protocols (i.e. CoAP) is being carried out within standardization organisms, such as IETF. In this pa-per, we propose a constrained version of the Session Initiation Protocol (SIP), named “CoSIP”, whose intent is to allow constrained devices to in-stantiate communication sessions in a lightweight and standard fashion. Session instantiation can include a negotiation phase of some parame-ters which will be used for all subsequent communication. CoSIP can be adopted in several application scenarios, such as service discovery and publish/subscribe applications, which are detailed. An evaluation of the proposed protocol is also presented, based on a Java implementation of CoSIP, to show the benefits that its adoption can bring about, in terms of compression rate with the existing SIP protocol and message overhead compared with the use of CoAP

    A Peer-to-Peer Secure VoIP Architecture

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    Voice over IP (VoIP) and multimedia real-time communications between two ore more parties are widely used over the Internet. The Session Initiation Protocol (SIP) is the current signaling standard for such applications and allows users to establish and negotiate any end-to-end multimedia session. Unfortunately current SIP-based platforms use a centralized architecture where calls between User Agents (UAs) are routed based on static public-reachable proxy servers, suffering of wellknown scalability and availability problems. Moreover security is currently poorly implemented and, when supported, it usually relies on a third-party trust relationship or on a Public Key Infrastructure (PKI). In this work we propose a completely distributed P2P VoIP architecture where calls are routed relying on a Location Service implemented through a Distributed Hash Table (DHT). End-to-end security is also provided without the use of any centralized server or PKI. Secure media sessions are established and authenticated on the basis of previously established sessions or by simple peer’s voice recognition. The proposed architecture has been also implemented and publicly released
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