1,721,006 research outputs found
Linear Wireless Networks with Variable Length and Density: Scaling Laws and Design Considerations
No full textIn this paper we consider linear wireless networks
with variable number of nodes. We first derive a basic cut-set
bound for transport capacity of this class of networks highlighting
the functional dependence on both node density and network
length. After, we investigate how transport throughput scales with
respect to node density δ in a wireless network with multihop
communication. While in linear multihop networks without
fading transport throughput does not increase by increasing node
density, i.e. it scales as δ0 with a gap with respect to capacity
bounds, we show that a capacity increase up to log δ is achieved
in the presence of fading by using, instead of a simple nearestneighbor
communication, suitable algorithms that adaptively
schedule source-destination links in the networks. Finally, we
compare multihop schemes with schemes based on distributed
MIMO communication by discussing the relevant differences and
showing that, despite the latter strategy is able to asymptotically
achieve scaling law bound approaching δ, multihop schemes
appear better in terms of capacity in a significant range of values
of δ and when the network becomes extende
On the Energy Efficiency of Multihop Communication in Wireless Sensor Networks
No full textIn this work we consider the energy efficiency of multihop communication in a wireless sensor network scenario. The system incorporates some relaying schemes based on node cooperation and forward error correction to improve the communication reliability in the presence of fading, and power control to reduce the energy consumed for transmission. We investigate the basic tradeoffs among energy consumption, hop distance and robustness against fading by assuming that routing and multiple access algorithms have already set up a path between source and destination. We address the design of hop distance from the point of view of energy efficiency by introducing a new metric, the energy consumption rate, function of the source-destination distance, and by deriving the optimal hop length that minimizes it. In our numerical results we compare the proposed relaying schemes from the point of view of reliability and energy efficiency. We will show that the use of node selection improves reliability without increasing energy consumption and the use of coding, which usually requires energy consuming processing, is convenient if implemented in a energy adaptive scheme or when long hops are required in low node-density networks
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
Interference Analysis for Optical Wireless Interconnections
No full textOptical wireless (OW) links have been recently proposed as an interconnection technology for multiple processing cores operating in parallel on the same chip. OW communication is also a mature option for indoor and outdoor applications. Design and analysis of networks with optical wireless links require a careful investigation of cross-link interference which plays a key-role on the performance and efficiency of systems that reuse the same channel for multiple parallel transmissions. In this paper we analyze the bit-error rate performance of OW links for on-chip applications with cross-link cochannel interference. As a novelty with respect to known literature on crosstalk in optical communications we consider asynchronous data transmission and address the system performance in case of heavy interference. Analytical methods are used to derive error probabilities as a function of signal-to-noise ratio (SNR), crosstalk power ratio, detection threshold, pulse shaping. Both exact and tight approximation methods are considered. As shown in the results, robustness against interference increases with asynchronous transmission, RZ pulse shaping and suitable design of detection threshold. It is also shown how the proposed analysis can be used to evaluate the reuse distance between two parallel links simultaneously transmitting in the same direction
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
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
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