1,720,957 research outputs found
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
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
Estimation of heavy rainfall during cyclonic storms from microwave observations using nonlinear approach over Indian Ocean
No full textIn this study, an effort has been made to study heavy rainfall events during cyclonic storms over Indian Ocean. This estimate is based on microwave observations from tropical rainfall measuring mission (TRMM) Microwave Imager (TMI). Regional scattering index (SI) developed for Indian region based on measurements at 19-, 21- and 85-GHz brightness temperature and polarization corrected temperature (PCT) at 85 GHz have been utilized in this study. These PCT and SI are collocated against Precipitation Radar (PR) onboard TRMM to establish a relationship between rainfall rate, PCT and SI. The retrieval technique using both linear and nonlinear regressions has been developed utilizing SI, PCT and the combination of SI and PCT. The results have been compared with the observations from PR. It was found that a nonlinear algorithm using combination of SI and PCT is more accurate than linear algorithm or nonlinear algorithm using either SI or PCT. Statistical comparison with PR exhibits the correlation coefficients (CC) of 0.68, 0.66 and 0.70, and root mean square error (RMSE) of 1.78, 1.96 and 1.68 mm/h from the observations of SI, PCT and combination of SI and PCT respectively using linear regressions. When nonlinear regression is used, the CC of 0.73, 0.71, 0.79 and RMSE of 1.64, 1.95, 1.54 mm/h are observed from the observations of SI, PCT and combination of SI and PCT, respectively. The error statistics for high rain events (above 10 mm/h) shows the CC of 0.58, 0.59, 0.60 and RMSE of 5.07, 5.47, 5.03 mm/h from the observations of SI, PCT and combination of SI and PCT, respectively, using linear regression, and on the other hand, use of nonlinear regression yields the CC of 0.66, 0.64, 0.71 and RMSE of 4.68, 5.78 and 4.02 mm/h from the observations of SI, PCT and combined SI and PCT, respectively
Performance Evaluation of Cooperative Relaying Systems with Channel Estimation Error and RF Impairments
No full textOver the past decade, cooperative communication has emerged as an attractive technique for overcoming the shortcomings of point-to-point wireless communication systems.
Cooperative relaying improves the performance of wireless networks by creating an array of multiple independent virtual sources transmitting the same information as the source node. In addition, when relays are deployed near the edge of the network, they can provide additional coverage in network blind spots. Interference in the network can also be reduced in cooperative communication systems as the nodes can transmit at lower power levels as compared to equivalent point-to-point communication systems. In practice, the actual benefit of multi-node cooperation is affected by a variety of factors, including the quality of Channel State Information (CSI), the constraints on the feedback and backhaul links, hardware impairments, resource allocation and data processing schemes. This thesis investigates the
combined impact of imperfect CSI and Radio Frequency Impairments (RFIs) on distributed relay networks and cellular relaying systems. First, we study the impact of CSI imperfections on single-antenna based dual-hop relaying systems in the presence of RFI over Nakagami-m fading environment. Herein, we consider two most common relaying protocols viz., Amplify-and-Forward (AF) and Decode-and-Forward (DF) to investigate the performance of One-way Relaying (OWR) system. To fully reap the benefits of relaying protocols, CSI of the network is essential.
In practice, CSI must be estimated using the pilot symbols prior to the transmission of data symbols. A unified analysis is conducted for both the relaying protocols by deriving the generalized closed-form outage probability expressions with channel estimation error and RFI. Moreover, we also analyze the outage performance with respect to the severity of channel conditions. The analytical results are used to obtain several crucial design insights such as the transmission rate and the combined level of imperfections that the system can handle without affecting its performance. Next, we extend our analysis to the cellular scenario where the wireless network comprises of multi-antenna Base Station (BS), single-antenna multiple users and multiple relays. Herein, we analyze the outage and Expected Spectral Efficiency (ESE) performance of downlink cellular relaying system in a Rayleigh fading environment. In particular, by employing joint antenna and relay selection with multi-user scheduling, we have proposed and analyzed two opportunistic transmission strategies for both AF and DF relaying protocols vii with different implementation complexities in practical scenario when the direct links
are in the deep fade. We also deduce the asymptotic outage expressions in the high signal-to-noise ratio regime, from which the impacts of CEE and RFI on the achievable
diversity order are highlighted. Moreover, to provide spectrally efficient transmission over traditional unidirectional flow of information, we consider another approach to improve the efficient transmission i.e., Two-Way Relaying (TWR) network. Specifically,
we analyze the performance of TWR-AF system with RFI at sources and the relay node. CEE is also considered for TWR network which creates imperfect self-interference
cancellation at both sources that exchange the information through a single relay. The expressions for effective end-to-end signal-to-noise plus-distortion-and-error ratio (SNDER) and closed-form expression for the exact analysis of OP are derived by taking a Rayleigh block fading channel. In addition, the combined impacts of RFI and CEE on outage
performance of TWR and OWR systems for low and high transmission rates are also evaluated. For further insights, we perform asymptotic analysis of OP and observe irreducible
outage floors which act as fundamental performance limits.
The last part of the thesis focuses on the comparative study of multi-user multi-relay TWR and OWR cooperative networks. Due to less implementation complexity involved in AF relaying protocol, we focus on AF relay assisted TWR and OWR systems with two groups of users exchanging information opportunistically over the best relay (out of available relay candidates) in the presence of CEE and RFI over Rayleigh fading channels. Considering such practical set-up, we first deduce the pertinent instantaneous end-to-end
SNDERs. Specifically, we derive approximate as well as exact closed-form expressions for the outage probability and expected spectral efficiency for both the systems. In addition, simple asymptotic expressions at the high SNR regime are obtained, which facilitate the characterization of the achievable diversity order of the systems. To validate the derived analytical expressions, we have presented simulation results which are sufficiently tight
across the entire range of SNRs. We have also optimized power to reduce system outages and emphasize that optimum power allocation can provide noticeable outage performance
improvement. Findings of the chapters suggest that full diversity order can be achieved only when the RF front-end hardware is assumed to be perfect, while in practice the imperfections in hardware are inevitable and reduce the diversity order of the system. Moreover, the influence of key parameters such as the number of users and relays on the system performance has been presented with the dependency on the level of RFI. Different design guidelines and possible power allocation between relay and end-user terminals are proposed to improve the system reliability under a total transmit power constraint
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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