1,720,959 research outputs found
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
The crack growth mechanism in asphaltic mixes
No full textThe crack growth mechanism in asphalt concrete (Ac) mixes is studied. In cyclic tests on several asphaltic mixes crack growth is measured, both with crack foils and with cOD-gauges. It is found that crack growth in asphaltic mixes is described by three processes which are parallel in time: cohesive crack growth in the mortar, adhesive crack growth between the mortar and the aggregates and a crack stoppers process. Differences in overall crack growth in asphalt concrete are due to differences in the contributions of each individual process to the overall process.Road and RailroadCivil Engineering and Geoscience
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
Winter damage of porous asphalt; Case study using a meso-mechanics based Tool for Lifetime Optimization of PA
No full textWith an increasing population in the Netherlands, people started to live relatively close to the primary road network. This led to major noise hindrance issues. As a solution it was decided to apply porous asphalt surfaces on the primary road network. These types of surface layers have a relatively open structure compared to traditionally applied dense asphalt mixtures. Application of porous surfaces brings along their first major advantage: noise reduction. A second major advantage of porous asphalt layers is an increased safety during rainfall. Due to its open structure water is stored and moved horizontally within the layer which reduces splash and spray effects and thus increases the visibility of drivers during rainfall. On the other hand the major disadvantage of porous asphalt layers is durability. The decisive factor for the relative short lifetime of porous asphalt is the loss of aggregates from the surface, also known as ravelling. This type of distress leads to a rough surface and decreases the material’s noise reduction potential. Further on the loosened particles cause damage to cars. In the winter ravelling develops at a much higher speed. This results in totally damaged sections as was noticed during the winter of 2009/2010 in the Netherlands. In this research a recently developed Lifetime Optimization Tool for porous asphalt was used to find out why different sections of the primary road network showed this type of excessive damage. Therefore LOT required information about the load, geometry and the response of these failed porous asphalt sections. In this research eight different sections were studied. The required input for LOT was determined directly from these eight sections. The results showed that in the winter the main cause for this increase in damage is caused by the reduced relaxation potential of the mortar of the mixture. Further on the calculated performance of the eight different sections was compared with the observed performance during the winter of 2009/2010 and it was shown that they were in good agreement with each other. From this it was concluded that the Lifetime Optimization Tool is capable of explaining winter damage of porous asphalt concreteRoad and Railroad EngineeringStructural EngineeringCivil Engineering and Geoscience
Development of a laboratory ageing method for bitumen in porous asphalt
No full textGenerally porous asphalt has lower durability than commonly used dense asphalt mixtures. Loss of aggregates from the pavement surface, called raveling, is the most common form of distress in porous asphalt. There are several factors that contribute to the accelerated failure or raveling of porous asphalt and among them ageing is believed to be the main reason for raveling failure of porous asphalt. It increases the chance of damage development because of applied traffic loading and thermal stresses at low temperature. During design phase of pavement, it is imperative to know beforehand what the properties of the pavement will be after field ageing. This will help to minimize maintenance cost due to premature failure and to increase the confidence level of the design of the pavement. It is evident; therefore, that there is a need for accelerated laboratory ageing method that can simulate binder properties similar to that of field aged binder. As a result this study was initiated and the objective was to develop a laboratory ageing procedure which is able to mimic binder properties of 7 years field aged porous asphalt pavement.Road and Railway EngineeringStructural EngineeringCivil Engineering and Geoscience
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