1,720,965 research outputs found
Distributed JXTA-based architecture for searching and retrieving solar data
No full textThis paper describes a hybrid distributed architecture, based on the JXTA technology, for searching and discovering data in a federation of solar observation archives. This work has been developed within the European project EGSO (European Grid of Solar Observations) with the intent of studying and analyzing a set of technologies and showing the brokerage capabilities of a highly controlled distributed network topology. Three roles have been identified: providers that contain data and metadata, brokers that manage providers and user queries, and consumers/clients. JXTA is used to develop all network system functionalities, while a native XML database is used to store resource descriptions
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
Wireless Sensor Networks and TSCH: a compromise between Reliability, Power Consumption and Latency
Full text linkReliability, power consumption, and latency are the three main performance indicators of wireless sensor networks. Time slotted channel hopping (TSCH) is a promising technique introduced in the IEEE 802.15.4 standard that performs some steps ahead in the direction of the final dream to meet all the previous requirements at the same time. In this article, a simple and effective mathematical model is presented for TSCH that, starting from measurements performed on a real testbed, permits to characterize both the network and the surrounding environment. To better characterize power consumption, an experimental measurement campaign was purposely performed on OpenMote B devices. The model, which was checked against a real 6TiSCH implementation, can be employed to predict network behaviour when configuration parameters are varied, in such a way to satisfy different application contexts. Results show that, when one of the three above indices is privileged, unavoidably there is a worsening of the others
Evaluating and Modeling IEEE 802.15.4 TSCH Resilience against Wi-Fi Interference in New-Generation Highly-Dependable Wireless Sensor Networks
Full text linkThanks to its ability to effectively counteract disturbance and interference, including the traffic generated by co-located Wi-Fi networks, Time Slotted Channel Hopping (TSCH) is currently gaining momentum in many application fields characterized by demanding reliability and determinism requirements. In particular, the ability of TSCH to change transmission frequency on every attempt sensibly mitigates packet losses and latencies, improving the overall behavior in a tangible way. In this paper, the communication quality achieved by TSCH in a setup that includes real motes exposed to a realistic interfering traffic is evaluated experimentally. A theoretical model is also developed, based on quite simple assumptions about the effectiveness of time and frequency diversity, which satisfactorily matches the real behavior. The model permits to determine how much network parameters like, e.g., the retry limit, actually affect communication, and can be exploited to find proper settings for them. Finally, the ability of channel hopping to prevent narrowband interference from disrupting communication is assessed. As results show, this mechanism makes motes suffer from an equivalent interference that roughly corresponds to the mean interference evaluated over all physical channels
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
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