1,720,990 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
Essays on microeconomics of transportation
No full textThe manuscript is organised into five sections. The first section is an introduction presenting my scientific position, my teaching activities, the management of studies, the supervision and animation of research, and finally the recent creation of the Association Française d'Economie des Transports of which I am vice-president. Sections 2, 3 and 4 present a collection of my recent contributions to transport economics research. Section 2 includes three articles analysing different manifestations and effects of congestion in public transport. The first looks at the effects of public transport congestion on user satisfaction, using a survey of stated preferences collected on the platforms of the Paris metro. The second studies the effects of congestion on users' choice of departure times. A microeconomic model is used to define the decentralised equilibrium and the social optimum, and to study the mechanisms for refocusing the social optimum. The third article examines the effects of congestion on the economies of scale of urban public transport operations. A microeconomic model is used to show that congestion phenomena (longer travel and waiting times, discomfort) appear when demand increases significantly, leading to diseconomies of scale and calling into question the subsidies granted to passengers during hyper peak periods. Section 3 contains two articles that study individual preferences for carpooling. The first article analyses these preferences for short-distance carpooling and the second for short-distance carpooling, using surveys of stated preferences collected through web-surveys. These preferences are analysed mainly by estimating the opportunity cost of travel time (or value of travel time) specific to each mode. Section 4 includes two papers that study the efficiency of regional rail services. The first studies price and frequency efficiency using a partial equilibrium model calibrated on two corridors: Ghent - Brussels in Belgium and Grenoble - Lyon in France. The second studies the productive efficiency of TER regional branches in France using a stochastic production frontier model. Finally, Section 5 presents my research perspectives in terms of method, topics and current and future projects
Pricing of myopic multi-sided platforms: theory and application to carpooling
No full textWorking Papers du LAET, 2023/02. ISSN : 2741-8103This paper investigates pricing decisions when a monopolistic multi-sided platform is myopic, that is unable to distinguish between two agents who participate on the same side of the platform but produce different externalities. We find that the structure of prices is the same for profit- and welfare-maximizing platforms. The unique price supplied to the two undistinguishable agents is a weighted average of the perfect information prices, where the weights depend on demand elasticities and externalities produced by the other undistinguishable agent. The prices supplied to the distinguishable agents are also affected by information asymmetry through an extra term than can be positive or negative. Introducing Hotelling competition does not affect results. We apply the model to a monopolistic short-distance carpooling platform with and without HOV lane, and show that the profit-maximizing platform does not subsidize efficiently the “good” side of the market, leading to very little traffic reduction. These results call for a discussion of the regulation of myopic platforms in general, and those of carpooling in particular
Why do (or don't) people carpool for long distance trips? A discrete choice experiment in France
No full textLong-distance carpooling is an emerging mode in France and Europe, but little is known about monetary values of this mode attributes in transport economics. We conducted a discrete choice experiment to identify and measure the values of attributes of long-distance transport modes for a trip as a driver and as a passenger, with a special focus on carpooling. Around 1.700 French individuals have been surveyed. We use discrete mixed logit models to estimate the probability of mode choice. We find that the value of travel time for a driver who carpools is on average 13% higher than the value of travel time when driving alone in his/her car. The average value of travel time for a carpool trip as passenger is around 26 euros per hour, 60% higher than for a train trip and 20% higher than for a bus trip. Moreover, our study confirms a strong preference for driving solo over taking carpoolers in one's car. We also show that individuals traveling as carpool passenger incur a "discomfort" cost of on average 4.5 euros per extra passenger in the same vehicle. Finally, we identify robust socioeconomic effects affecting the probability of carpooling, especially gender effects. When they drive a car, females are less likely to carpool than male, but they prefer to carpool two passengers over only one passenger. JEL Codes: R41; C3
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
Pricing of myopic multi-sided platforms: theory and application to carpooling
No full textWorking Papers du LAET, 2023/02. ISSN : 2741-8103This paper investigates pricing decisions when a monopolistic multi-sided platform is myopic, that is unable to distinguish between two agents who participate on the same side of the platform but produce different externalities. We find that the structure of prices is the same for profit- and welfare-maximizing platforms. The unique price supplied to the two undistinguishable agents is a weighted average of the perfect information prices, where the weights depend on demand elasticities and externalities produced by the other undistinguishable agent. The prices supplied to the distinguishable agents are also affected by information asymmetry through an extra term than can be positive or negative. Introducing Hotelling competition does not affect results. We apply the model to a monopolistic short-distance carpooling platform with and without HOV lane, and show that the profit-maximizing platform does not subsidize efficiently the “good” side of the market, leading to very little traffic reduction. These results call for a discussion of the regulation of myopic platforms in general, and those of carpooling in particular
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