1,720,999 research outputs found
Responsive protocols for distributed multimedia applications
No full textA relevant class of Distributed MultiMedia Applications (DMMAs) can be implemented to support critical activities from which either financial investments, or human lives, or both, may depend. These DMMAs can be distributed across wide geographical distances; owing to their critical nature, the principal requirements they exhibit include the need for scalable services that be both timely and highly available (i.e. responsive). In order to provide support to these DMMAs, we have designed and developed a communication software architecture that meets effectively these requirements. In this paper, we introduce that architecture, and discuss its performance as resulting from a prototype implementation we have developed. © Springer-Verlag Berlin Heidelberg 2000
Synchronization support and group-membership services for reliable distributed multimedia applications
No full textWe describe a collection of algorithms designed to support reliable synchronization and group membership services for distributed multimedia applications. In particular, we consider those applications that require interactivity, isochronous rendering of multimedia data, and high reliability. We show that the algorithms we propose (i) provide reliable support for the synchronization of multimedia data streams, despite the occurrence of possible communication failures, (ii) maintain a consistent view of the relative group membership of all the nonfaulty application components, (iii) guarantee time-bounded delay of component failure detection and join, and (iv) meet effectively possible scalability requirements of the applications
Client-centered load distribution: A mechanism for constructing responsive Web services
No full textIn this paper we describe the design, implementation and experimental evaluation of a software mechanism that supports responsive (i.e. highly available and timely) Web services, constructed out of replicated servers. Specifically, this mechanism operates by engaging all the available replicas in supplying a fragment of the Web document that a client requires. The size of the fragment a replica is requested to supply is dynamically evaluated on the basis of the response time that replica can provide its client with. In addition, the proposed mechanism can dynamically adapt to changes in both the network and the replica servers' status, thus tolerating possible replica or communication failures that may occur at run-time. The performance results we have obtained from our experimental evaluation illustrate the adequacy of the mechanism we propose
The implementation of middleware services for QoS-aware distributed multimedia applications
No full textIn this paper we address issues of design of middleware services that can meet effectively application-level (i.e., end-to-end) QoS requirements of Internet-based, latency-sensitive multimedia applications. In this context, we describe a set of adaptive middleware services that we have developed, based on a commercial middleware platform, in order to support an IP-based telephony application over the Internet; in addition, we summarize the performance results we have obtained from a prototype implementation of these services
Communication support for critical distributed multimedia applications: An experimental study
No full textIn this paper, we summarize the design and prototype implementation of a communication software architecture we have developed in order to support critical Distributed Multimedia Applications (DMMAs), and discuss its performance. This discussion illustrates the adequacy of our approach in the design of communication software for critical DMMAs
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
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