1,720,958 research outputs found
Phoenix: A Hybrid Cooperative-Network Coding Protocol for Fast Failure Recovery in Ad Hoc Networks
No full textOn encoding and rate adaptation for MIMO_NC
No full textMIMO_NC is a recently proposed physical layer technique that combines MIMO signal processing and Network Coding. However, it has also been shown that the diversity offered by MIMO_NC cannot be greater than what standard NC offers. In this paper we propose a new encoding strategy for MIMO_NC that improves the diversity order and a rate adaptation technique tailored on MIMO_NC that offers diversity and coding gain over conventional NC
On the viability of a Cooperative-Network Coding Protocol in Clustered Networks
No full textThe interaction between cooperation and network coding has lately received a significant deal of attention, as a combination of the two brings novelty, flexibility and improved performance. However, there is a lack of studies about real-world scenarios. In this paper, we analyze the performance of an existing cooperative-NC protocol for clustered networks, where all nodes connect in a single hop fashion to a cluster head. This is representative of environments like WLANs, mesh networks, last mile connectivity or ad hoc networks where some nodes create an infrastructure for the others. We show that our system is able to improve network throughput by as much as 15% and network capacity by 20% over decode-and-forward cooperative protocols
Network Coding meets MIMO
No full textIn this paper, MIMO techniques are applied to network coding in order to exploit the spatial diversity inherent in packet combining. This is possible because network coding and MIMO solve similar problems, namely to decode a vector of transmitted symbols given a vector of received samples. This observation leads to a new approach for NC coding/decoding. Our basic idea is to move network coding functionalities towards the physical layer in order to jointly perform NC decoding and MIMO detection and gain the advantages of the two approaches. We refer to this new strategy as MIMO_NC. Theoretical analysis and simulations prove that our system is more robust than traditional network coding to fading and packet losses
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
- …
