1,720,996 research outputs found
Aircraft turnaround and industrial actions: how ground handlers' strikes affect airport airside operational efficiency
No full textThe efficiency of airport turnaround operations has often been compromised by various disruptive events out of the airlines' control, such as strikes, which negatively influence the punctuality and regularity of operations. The purpose of this work is to determine the loss of airport operational performance provoked by ground handlers' industrial actions. A discrete-event simulation model of both aircraft landing-and-takeoff (LTO) cycles and turnaround operations has been built by using AnyLogic. If the number of ground handler's operators decreases, turnaround operations require more time to be performed, resulting in delayed departures and knock-on delays. For the case study of Lisbon “Humberto Delgado” airport, turnaround time increases more than linearly with respect to the decrease of staff resources in service. When the number of operators decreases under a certain threshold, turnaround lengthening cannot be absorbed by buffer times and departure delays propagate in cascade over the day. This threshold should call for emergency actions and contingency plans
Micro-simulation of airport taxiing procedures to improve operation sustainability: Application of semi-robotic towing tractor
No full textCarbon footprint assessment due to airport operations is often required by environmental regulations. Aircraft contribute to local air pollution during the Landing and Take Off cycle. A big portion of the time aircraft spend on the ground is taken by taxi operations. Taxi times also increase at higher rates than traffic demand because of congestion at airports. Several measures are explored in the literature regarding the mitigation of taxi related emissions. These measures are often assessed by means of analytical approaches. In this article, the authors introduce a new micro simulation approach to assess aircraft ground movements with the aim of providing a more realistic estimation of taxi times. The approach is based on the definition of a discrete event model using a generic simulation software, AnyLogic 7. The new model is then used to assess the potential benefits and impacts deriving from the introduction of an environmental friendly taxi procedure at Lisbon International Airport. The simulated procedure envisages the utilization of TaxiBot, a semi-robotic towbarless tractor suitable for dispatch towing at medium to large airports. Results prove the alternative measure would potentially lead to environmental benefits in terms of fuel saved and emissions reduction. Considering an average day, both airports and airlines would gain in terms of, respectively, emitted pollutants and operational costs. Starting from these observations, possibilities for further research are explored
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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