1,720,958 research outputs found
A prediction based UPC mechanism for VBR video traffic
No full textPreventive actions have to be used to avoid congestion in ATM networks. These actions are represented by Call Admission Control (CAC) and Usage Parameter Control functions (UPC). In this paper two UPC algorithms are compared and an Enhancement of the Leaky Bucket mechanism is presented. The comparison is based an the results of several trace driven simulations. The simulations, realised an a CAMAD tool, are driven by MPEG1 Video traces as input traffic. The effectiveness of the proposed algorithm has been evaluated in terms of response time and transparency. These performance indexes have been obtained considering the number of non-conforming cells and the mean value of the conforming cells path
A Multiplexing Scheme using a Prediction Based Scheduling Strategy for Self-Similar Traffic
No full text
A Wavelet-based approach to the estimation of the Hurst Parameter for self-similar data
No full textIn this paper we analyze a wavelet based method for the estimation of the Hurst parameter of synthetically-generated self-similar traces, widely used in a great variety of applications, ranging from computer graphics to parsimonious traffic modelling in broadband networks. The aim of this work is to point out the efficiency of multiresolution schemes in the analysis of fractal processes, characterized by similar statistical features over different time scales. To this end we generated a huge amount of data using tile Random Midpoint Displacement (RMD) algorithm, a well-known fast technique for the generation of the fractional Gaussian noise (fGn) traces. We then evaluated the Hurst parameter of such sequences in the wavelet domain and compared the results with those obtained with more traditional methods, based on the estimation of the fractal dimension (Higuchi method) and the moments of the aggregated series
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
Statistical Multiplexing of self-similar VBR videoconferencing traffic
No full textATM based telecommunication networks are designed to obtain high resource utilization by means of statistical multiplexing of traffic sources corresponding to heterogeneous multimedia services.
As highlighted by recent measurements and statistical studies, these applications are quite different from traditional narrowband services. Particularly, self similarity and long range dependence, that charaterise the bursty nature of the Traffic pattern, have been pointed out as a very predominant characteristic in the design of new networks.
In order to achieve an efficient resource utilisation, peak rate allocation must be substituted by a type of dynamic rate allocation.
This paper presents a Dynamic Bandwidth Allocation method that employs linear prediction of the input rate based on selfsimilar modelling of data. The performances of the proposed strategy, in terms of multiplexing gain for reasonable values of cell loss rate and queuing delay, have been evaluated considering experimental data collected over a DQDB MAN during a multiparty videoconferencing session
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
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