1,720,979 research outputs found
Development of network-level pavement deterioration curves using the linear empirical Bayes approach
Full text linkModelling the pavement deterioration process is essential for a successful pavement management system (PMS). The pavement deterioration process is highly influenced by uncertainties related to data acquisition and condition assessment. This paper presents a novel approach for predicting a pavement deterioration index. The model builds on a negative binomial (NB) regression used to predict pavement deterioration as a function of the pavement age. Network-level pavement condition models were developed for interstate, primary, and secondary pavement road families and were compared with traditional non-linear regression models. The linear empirical Bayesian (LEB) approach was then used to improve the predictions by combining the deterioration estimated by the fitted model and the observed/measured condition recorded in the PMS. The proposed approach can improve the mean square error prediction of the next-year pavement condition by 33%, 36% and 41% for Interstate, Primary, and Secondary roads, respectively, compared with the measured pavement condition without further modelling of the pavement deterioration
Approaches To Weighting Within Transportation Infrastructure Sustainability Assessment
No full textSustainability assessment systems are increasingly being used as tools to encourage more sustainable practices in the provision of civil infrastructure. In several cases, agencies have developed unique sustainability assessment systems, or adopted modified versions of sustainability assessment systems currently available for a wider market. In any case, the nature of sustainability as a multi-criteria problem requires that preferences must be expressed in order to determine optimal outcomes for more sustainable decision making. These preferences are typically expressed in terms of weights applied to the various criteria in sustainability assessment systems, and the techniques used to derive these weights, as well as how the weights are applied, varies across the many different systems. In this paper, the authors review how weighting is typically included in sustainability assessment systems and make recommendations about how some of the incongruities between the various systems can be understood. Furthermore, the authors present the results from a pilot study which was conducted using an online survey system, and then use the results to make recommendations regarding future surveys designed to elicit weights from such a group
Performance based maintenance contracts for sub-national roads: experience from Latin America.
No full textLife-cycle analysis of a new composite material for bridge pavementwaterproofing
No full textone of the most critical issues related to bridge management and preventive maintenance is deck waterproofing. Infiltration of meteoric and rain-wash water into the bridge asphalt pavement through unsealed cracks could produce a series of chain events that leads towards an accelerated decay of the bridge structural adequacy. Actions like crack sealing and general waterproofing are main activities; they can in fact slow down the deterioration and reduce the life-cycle costs. An effective protection system against water is one of the key factors for a functional and efficient bridge management plan. However, benefits associated
with such maintenance activities are seldom correctly accounted and, in many instances, they are not even considered at all. Consequently many road bridge authorities do not include pavement preventive maintenance activities in their infrastructures management programs. Recent research has resulted in the development of new technologies in the field of crack sealing and pavement waterproofing. In this context, a new composite material for waterproofing interlayer membranes, to be “cold applied” (with great benefit for environment and workers) was studied and also tested in full scale experiments by Politecnico of Milano researchers. This paper presents the main characteristics and the performances of this new technology, applied to bridge pavements, followed by a life-cycle analysis to quantitatively show the savings of the road bridge authority and the benefits of the users (in terms of improved condition of the bridge pavement surface). The results obtained are of general validity as they can be extended to all similar technologies
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
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