1,720,958 research outputs found
Does OVX affect WTI and Brent oil spot variance? Evidence from an entropy analysis
No full textThis paper examines the flow of information and its direction between the oil volatility index (OVX) and the spot variance of WTI and Brent returns. Since OVX is an indicator of the investor sentiment about oil market performance, we aim first at evidencing whether there is an exchange of information between OVX and the spot variance of the two crudes. Moreover, since OVX is linked to WTI crude oil, it is useful to investigate whether it shares an information content with Brent. To this purpose, we propose an entropy-based approach which exploits two non-parametric methods: the mutual information and the transfer entropy. The results show an increase in the information flow between OVX and the spot variance of Brent returns and a corresponding decrease in the information flow with WTI. Furthermore, the direction of the information flow comes from OVX to both oil spot variances, thus investor sentiment about oil market performance drives uncertainty in the corresponding spot market. However, the information flow from the oil spot variances to OVX is more statistically significant for WTI than for Brent and, since transfer entropy is a measure of resolution of uncertainty, we demonstrate that the spot variance of WTI returns helps more in reducing uncertainty about OVX (than Brent)
Decoupling and recoupling in the crude oil price benchmarks: An investigation of similarity patterns
No full textThe aim of this paper is to investigate the decoupling and recoupling of WTI and Brent prices also with respect to the debate on the regionalisation-globalisation of the two oil markets.To this purpose, we employ the Dynamic Time Warping (DTW) algorithm to identify decoupling events between the two crude oil price series. DTW has been employed for classification and clustering aims in many fields, but in this paper we make a slightly different application of DTW with respect to those provided by the literature, demonstrating how DTW can be employed also to investigate the decoupling between the two oil benchmarks. Our analysis reveals that the two oil benchmarks decouple and recouple according to WTI local market conditions. Therefore, we found evidence that WTI-Brent market is not fully integrated at all times. We also propose two DTW-based indexes: Relative-Alignment Index (RAI) and Warping Index. The first confirms that the greatest decoupling between WTI and Brent occurs because of WTI local market conditions and is useful in highlighting the main decoupling between our crude oil series over time, while the second provides information on the time window of crude oil price decoupling. Lastly, we provide some policy implications based on our results
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
Auction-based Theory for Dynamic Spectrum Access: A Review
No full textWith the advent of 5G (and beyond) technologies, efficient exploitation of radio spectrum resources is becoming the fundamental block of the new digital economy. Unfortunately, current static radio spectrum allocation policies are introducing an artificial spectrum scarcity problem. In this context, cognitive radio and spectrum licensing have been proposed as effective ways to guarantee adequate quality of service. In particular, the radio spectrum auction design is both answer and efficient solution to these problems. This paper provides a survey on auction-based methods applied to radio spectrum allocation in cognitive radio networks. We first outline the characteristics of radio spectrum regulation and spectrum sharing, as well as the advantages of a dynamic spectrum access framework. Then, we introduce the economic properties of conventional auctions. Finally, we present a comprehensive taxonomy of auction-based methods applied to spectrum allocation in cognitive radio networks, as well as their characteristics, and implementation issues that will improve the actual radio spectrum allocation mechanism
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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