1,721,007 research outputs found
Understanding route switch behavior: An analysis using GPS based data
No full textThe objective of this paper is to study route switch behavior to detect which trip and individual characteristics most influence the
choice of multiple routes for the same origin-destination (OD) trip. In this study we used a database of 361 morning commute
trips, regarding 66 users, collected in the metropolitan area of Cagliari (Italy) during the “Casteddu Mobility Styles” survey. Data
were collected for a 14 days period through a personal probe system called Activity Locator (Meloni, et al., 2011), a smartphone
that integrates a GPS logger for the acquisition of the routes and an activity/travel diary. Mixed logit models are estimated, in
order to take into account the variability of user perception. Results show that route switch behavior is influenced by the number
of traffic lights per km, percent of highways, time perception, gender, age, individual income and driving experience in relation
with the minutes per km
Estimating Route Choice Models from Stochastically Generated Choice Sets on Large-Scale Networks. Correcting for Unequal Sampling Probability
No full textRoute choice is one of the most complex decision-making contexts to
represent mathematically, and the most frequently used approach to
model route choice consists of generating alternative routes and modeling
the preferences of utility-maximizing travelers. The main drawback
of this approach is the dependency of the parameter estimates from
the choice set generation technique. Bias introduced in model estimation
has been corrected only for the random walk algorithm, which has
problematic applicability to large-scale networks. This study proposes
a correction term for the sampling probability of routes extracted with
stochastic route generation. The term is easily applicable to large-scale
networks and various environments, given its dependence only on a random
number generator and the Dijkstra shortest path algorithm. The
implementation for revealed preferences data, which consist of actual
route choices collected in Cagliari, Italy, shows the feasibility of generating
routes stochastically in a high-resolution network and calculating
the correction factor. The model estimation with and without correction
illustrates how the correction not only improves the goodness of fit but
also turns illogical signs for parameter estimates to logical signs
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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