1,720,963 research outputs found
Modelling and Predicting the Data Availability in Decentralized Online Social Networks
No full textMaintaining data availability is one of the biggest challenges in Decentralized Online Social Networks (DOSN). In the existing work of improving data availability in DOSN, it is often assumed that the friends of a user are always capable of contributing sufficient storage capacity to store all the data published by the user. However, this assumption is not always true for today's Online Social Networks (OSNs) for the following reasons. On one hand, the increasingly more data are being generated on the OSNs nowadays. On the other hand, current users often use the smart mobile devices to access the OSNs. These two factors cause the shortage of the storage capacity in DOSN, where the published data are supposed to be stored within a friend circle. The limitation of the storage capacity may jeopardize the data availability. Therefore, it is desired to know the relation between the storage capacity contributed by the OSN users and the level of data availability that the OSN can achieve. This paper addresses this issue. In this paper, the data availability model over storage capacity is established. Further, a novel method is proposed to predict the data availability on the fly. Extensive simulation experiments have been conducted to evaluate the effectiveness of the data availability model and the on-the-fly prediction. The data availability model can be used by the OSN designers to determine the storage capacity for the published data in order to achieve the desired data availability. The on-the-fly prediction method can help the data replication and storage policies make judicious decisions at runtime
Cadros: The Cloud-Assisted Data Replication in Decentralized Online Social Networks
No full textOnline Social Network (OSN) services are very popular nowadays. In order to protect the data privacy, Decentralized Online Social Network (DOSN) services have been proposed. In DOSN, the data published by a user and the data replicas are only stored in the friend circle of the user. Although full replication can improve Data Availability (DA), pure DOSNs may not be able to deliver sustainable data availability. This paper proposes a Cloud-Assisted scheme, called Cadros, to improve the DA in DOSN. This paper conducts quantitative analysis about the storage capacity of Cadros as the result of integrating the Cloud into DOSN, and further models and predicts the level of DA that Cadros can achieve. Extensive simulation experiments have been conducted to verify the effectiveness of Cadros
Modelling and developing conflict-aware scheduling on large-scale data centres
No full textLarge-scale data centres are the growing trend for modern computing systems. Since a large-scale data centre has to manage a large number of machines and jobs, deploying multiple independent schedulers (termed as distributed schedulers in literature) to make scheduling decisions simultaneously has been shown as an effective way to speed up the processing of large quantity of submitted jobs and data. The key drawback of distributed schedulers is that since these schedulers schedule different jobs independently, the scheduling decisions made by different schedulers may conflict with each other due to the possibility that different scheduling decisions refer to the same subset of the resources in the data centre. Conflicting scheduling decisions cause additional scheduling attempts and consequently increase the scheduling cost. More resources each scheduler demands, higher scheduling cost may incur and longer job response times the users may experience. It is useful to investigate the balanced points in terms of resource demands for each of independent schedulers, so that the distributed schedulers can all achieve decent job performance without experiencing undesired resource competition. To address this issue, we model distributed scheduling and resource conflict using the game theory and conduct the quantitative analysis about scheduling cost and job performance. Further, based on the analysis, we develop the conflict-aware scheduling strategies to reduce the scheduling cost and improve job performance. We have conducted the simulation experiments with workload trace and also real experiments on Amazon Web Services (AWS). The experimental results verify the effectiveness of the proposed modelling approach and scheduling strategies
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
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
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