1,720,986 research outputs found
Analysis and Forecasting of Web Content Dynamics
No full textWeb content changes have a strong impact on
search engines and more generally on technologies dealing with
content retrieval and management. These technologies have to
take account of the temporal patterns of these changes and
adjust their crawling policies accordingly. This paper presents
a methodological framework – based on time series analysis –
for modeling and predicting the dynamics of the content changes.
To test this framework, we analyze the content of three major
news websites whose change patterns are characterized by large
fluctuations and significant differences across days and hours.
The classical decomposition of the observed time series into trend,
seasonal and irregular components is applied to identify the
weekly and daily patterns as well as the remaining fluctuations.
The corresponding models are used for predicting the future
dynamics of the sites based on their current and historical
behavior
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
Time series analysis of the dynamics of news websites
Full text linkAbstract-The content of news websites changes frequently and rapidly and its relevance tends to decay with time. To be of any value to the users, tools, such as, search engines, have to cope with these evolving websites and detect in a timely manner their changes. In this paper we apply time series analysis to study the properties and the temporal patterns of the change rates of the content of three news websites. Our investigation shows that changes are characterized by large fluctuations with periodic patterns and time dependent behavior. The time series describing the change rate is decomposed into trend, seasonal and irregular components and models of each component are then identified. The trend and seasonal components describe the daily and weekly patterns of the change rates. Trigonometric polynomials best fit these deterministic components, whereas the class of ARMA models represents the irregular component. The resulting models can be used to describe the dynamics of the changes and predict future change rates
Performance Evaluation of Mail Systems
No full textElectronic mail is the core of modern communications. People rely on email to conduct their business and stay in touch with families and friends. The ubiquity and popularity of email make its QoS an important issue. Performance of mail systems is the result of the interactions between their hardware and software components and the user behavior, that is, how users exploit and exercise these components. This paper addresses the performance issues of mail systems by focusing on the characterization of their workloads and on benchmarking. The mail systems considered in this paper rely on Internet standard messaging protocols
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