1,721,243 research outputs found
Time-scale transformations: effects on VaR models
No full textThis paper investigates the effects of using temporal aggregation rules in the evaluation of the maximum portfolio loss. In particular, we propose and compare different time aggregation rules for VaR models. We implement time-scale transformations for: (i) a EWMA model with Student's t conditional distributions, (ii) a stable sub-Gaussian model, (iii) a stable asymmetric model. All models are subjected to backtest on out-of-sample data in order to assess their forecasting power and to show how these aggregation rules perform in practice
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
Processing High-volume Geospatial Data: A Case of Monitoring Heavy Haul Railway Operations
Get PDFAbstractSensor technology such as GPS can be used in the mapping of transportation networks (e.g., road, rail). However, GPS suffers from errors in positional accuracy due to factors such as signal arrival time. In railway systems, positional accuracy is of utmost importance to iden- tify state of track and wagons for safety and maintenance. Along with GPS, the numerous lightweight sensors installed in each wagon produce a high-velocity geospatial data that needs to be processed continuously and the traditional data processing and storage applications can not handle it. We propose efficient algorithms and a suitable data structure to achieve rapid and accurate location mappings. Our large-scale evaluation demonstrates that the system is accurate and capable of real-time performance
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
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