1,720,966 research outputs found
Le réseau basé sur les informations (ICN), une conception naturelle pour l'Internet des Objets?
No full textThe Internet of Things (IoT) is commonly perceived as the extension of the current Internet to our physical world. It interconnects an unprecedented number of sensors/actuators, referred as things, to the Internet. Facing the important challenges imposed by devices heterogeneity and the tremendous generated traffic, the current Internet protocol suite has reached its limits. The Information-Centric Networking (ICN) has recently received a lot of attention as a potential Internet architecture to be adopted in an IoT ecosystem. The ICN paradigm is shaping the foreseen future Internet architecture by focusing on the data itself rather than its hosting location. It is a shift from a host-centric! communication model to a content-centric one supporting among! others unique and location-independent content names, in-network caching and name-based routing. By leveraging the easy data access, and reducing both the retrieval delay and the load on the data producer, the ICN can be a viable framework to support the IoT, interconnecting billions of heterogeneous constrained objects. Among several ICN architectures, the Named Data Networking (NDN) is considered as a suitable ICN architecture for IoT systems. Nevertheless, new issues have emerged slowing down the ambitions besides using the ICN paradigm in IoT environments. In fact, we have identified three major challenges. Since IoT devices are usually resource-constrained with harsh limitations on energy, memory and processing power, the adopted in-network caching techniques should be optimized. Furthermore, IoT data are transient and frequently updated by the producer which imposes stringent requirements to maintain cached data freshness. Finally, in IoT scenario, devices are ! frequently mobile and IoT applications require keeping data continuity. In this thesis, we propose a caching strategy that considers devices constraints. Then, we introduce a novel cache freshness mechanism to monitor the validity of cached contents in an IoT environment. Furthermore, to improve caching efficiency, we also propose a cache replacement policy that targets to raise the system performances and maintain data freshness. Finally, we introduce a novel name-based routing for NDN/IoT networks to support the producer mobility. We simulate and compare our proposals to several relevant schemes under a real traffic IoT network. Our schemes exhibit good system performances in terms of hop reduction ratio, server hit reduction ratio, response latency and packet loss, yet it provides a low cache cost and significantly improves the content validity.L'Internet des Objets (IdO) est généralement perçu comme l'extension de l'Internet actuel à notre monde physique. Il interconnecte un grand nombre de capteurs / actionneurs, référencés comme des objets, sur Internet. Face aux importants défis imposés par l'hétérogénéité des dispositifs et l'énorme trafic généré, la pile protocolaire actuelle TCP / IP va atteindre ses limites. Le réseau centré sur l'information (ICN) a récemment reçu beaucoup d'attention comme une nouvelle architecture Internet qui a un grand potentiel pour être adoptée dans un système IdO. Le paradigme ICN forme la future architecture Internet qui s’est contrée sur les données elles-mêmes plutôt que sur leurs emplacements dans le réseau. Il s'agit d'un passage d'un modèle de communication centrée sur l'hôte vers un système centré sur le contenu en se basant sur des noms de contenu uniques et indépendants de la localisation, la mise en cache dans le réseau et le routage basé sur les noms. Grâce à ses avantages pertinents, l'ICN peut être un framework viable pour soutenir l’IdO, interconnectant des milliards d'objets contraints hétérogènes. En effet, ICN permet l'accès facile aux données et réduit à la fois le délai de récupération et la charge des requêtes sur les producteurs de données. Parmi plusieurs architectures ICN, le réseau de données nommées (NDN) est considéré comme l'architecture ICN appropriée pour les systèmes IdO. Néanmoins, de nouveaux problèmes ont apparu et s'opposent aux ambitions visées dans l'utilisation de la philosophie ICN dans les environnements IdO. En fait, nous avons identifié trois défis majeurs. Étant donné que les périphériques IdO sont habituellement limités en termes de ressources avec des limitations sévères de l'énergie, de la mémoire et de la puissance de traitement, les techniques de mise en cache en réseau doivent être optimisées. En outre, les données IdO sont transitoires et sont régulièrement mises à jour par les producteurs, ce qui impose des exigences strictes pour maintenir la cohérence des données mises en cache. Enfin, dans un scénario IdO, les objets sont souvent mobiles et nécessitent des stratégies pour maintenir leurs accessibilités. Dans cette thèse, nous proposons une stratégie de mise en cache optimale qui considère les contraintes des périphériques. Ensuite, nous présentons un nouveau mécanisme de cohérence de cache pour surveiller la validité des contenus mis en cache dans un environnement IdO. En outre, pour améliorer l'efficacité de la mise en cache, nous proposons également une politique de remplacement du cache qui vise à augmenter les performances du système et à maintenir la validité des données. Enfin, nous introduisons un nouveau routage basé sur les noms pour les réseaux NDN / IdO afin de prendre en charge la mobilité des producteurs.Nous simulons et comparons nos propositions à plusieurs propositions pertinentes sous un réseau IdO de trafic réel. Nos contributions présentent de bonnes performances du système en termes de taux de réduction du chemin parcouru par les requêtes, de taux de réduction du nombre des requêtes satisfaites par les serveur, du délai de la réponse et de perte des paquets, de plus, la stratégie de mise en cache offre un faible coût de cache et finalement la validité du contenu est considérablement améliorée grâce au mécanisme de cohérence
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
Proxy re-encryption for privacy enhancement in Blockchain: Carpooling use case
No full textInternational audienceBlockchain is an especially promising and revolutionary technology that brings transparency in a scalable wayfor multiple organizations and this is thanks to its severalfeatures. There are some exciting blockchain features butamong them, decentralization is undoubtedly the most interesting one. Organizations can share data within a distributedledger. As a consequence, each one can access synchronizeddata stored in its local Blockchain node. This functionalityimproves transaction tracking and facilitates access to datawithin a private group of organizations. However, in somecases, even if organizations accept to share data, they requireto hide some private information related to their users or theirbusiness model. To tackle privacy and trust issues betweenorganizations, this paper presents a blockchain architecturebased on the proxy re-encryption scheme. This scheme is integrated within smart contracts to provide a very efficient, fast,and secure platform. The proposed architecture is implementedin an Hyperledger Blockchain and tested in a real transportand mobility use case
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
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe 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
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe 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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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