1,720,956 research outputs found
Optimal Deployment of Open-Source Application Servers providing Multimedia Services
No full textThis article shows the usage and the experimental analysis of open source software packages for designing and implementing carrier-grade multimedia services. The shown implementation is based on the use of Java Call Control APIs for managing SIP sessions and MGCP connections. This JCC implementation has been integrated within an open source platform, Mobicents JSLEE. Mobicents is a runtime environment suitable for deploying services integrating voice, video, and messaging over different networks. An extensive experimental campaign has allowed suitable deployment strategies to be identified, depending on the service features. The main contribution of this article is to present these strategies, consisting of resource allocation and configuration in a virtualized environment. The results of our experiments are aimed at providing general guidance on configuring servers in a virtualized environment such as a cloud. They can also be helpful to address the server placement problem, which is beyond the scope of this article. An additional contribution of this article consists of a simple and effective model to predict the achievable server throughput, expressed in calls per second. For this purpose, we have measured the CPU time for processing SIP and MGCP messages, and estimated the maximum sustainable load of each virtual machine. In this way, we can preliminarily estimate the number of virtualized instances of the platform needed for handling a given workload with the desired quality of service
Enhancing java call control with media server control functions
No full textIn this article, we propose a novel abstraction layer for application service implementation compliant with the Java Call Control (JCC) specifications. It simplifies creation of multimedia services using SIP and the Media Gateway Control Protocol. In order to show its effectiveness, we have implemented a JCC resource adaptor for a JAIN service logic execution environment (JSLEE), using the Mobicents application server, which is the only existing open source JSLEE implementation. Experimental results obtained by implementing a complex VoIP service show both a significant simplification of service implementation and improved performance over legacy solutions
An Extended Java Call Control for the Session Initiation Protocol
No full textIn this paper we propose a functional mapping between Java Call Control (JCC) and Session Initiation Protocol (SIP). We show its effectiveness in enabling easy service design and implementation through experimental results. For this purpose, we have implemented a JCC-SIP Resource Adaptor for a Jain Service Logic Execution Environment (JSLEE). In particular, we have used the Mobicents JSLEE, which is the only existing open source JSLEE implementation. Results, obtained by implementing a typical VoIP service, show both feasibility and good performance of our proposal
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
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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