1,720,961 research outputs found
Impacts of Connected Automated Vehicles on Large Urban Road Network
No full textAs an essential component of the Cooperative Intelligent Transportation System (C-ITS), Connected Automated Vehicles (CAVs) are anticipated to play a significant role in the development of the future mobility service. This paper investigates the impacts of different penetration of CAVs on the urban road network. The investigation is carried out in a vast urban network with Simulation of Urban MObility (SUMO), a microscopic traffic simulator. The estimated factors of the network are network maximum flow, critical density, average speed, congestion duration, and roadway over-saturation degree. The Macroscopic Fundamental Diagram (MFD) has been used to estimate the maximum flow and critical density. In a simulation way, it substantiated that a road network could have less scattered MFDs, even if the traffic flow is distributed heterogeneously. The congestion duration and over-saturation degree are used to check traffic congestion. The simulation results show that applying 100% CAVs can contribute about a 13.55% increase in maximum flow. A similar trend can be found in the critical density for different CAV penetration rates. In a similar congestion situation, the network with 100% CAV driving in can carry more than 130% of the original travel demand. In terms of congestion level, even a low CAV penetration rate may significantly improve the traffic condition
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
Route guidance systems based on the macroscopic fundamental diagram concept: A Simulation-Based Case Study in the city of Portici
Full text linkRecently, traffic management strategies, leveraging the Macroscopic Fundamental Diagram (MFD) paradigm, have gained a lot of interest since they allow to enhance urban network performance in term of efficiency and energy saving. Within this framework, this paper proposes a route guidance control system that, on the basis of traffic condition of each region, suggests to vehicles the best admissible route to follow. More specifically, a linear model is used to predict the evolution of traffic condition of each region over time on the basis of traffic data collected by loop detectors and, then, the MFD paradigm is exploited to estimate the time required to cross each region. In so doing, the control system computes the travel time of each admissible route and, in the end, suggests to each vehicle the one that minimize the travel time to reach a specific destination. Numerical simulations, carried out by exploiting SUMO microscopic traffic simulator and MATLAB, are performed to assess the effectiveness of the proposed control strategy in enhancing both the mobility and the environmental performances of the city network of Portici. The case without the control system is used as a base scenario. Results prove the effectiveness of the proposed routing control strategy in enhancing both mobility and environmental performance of the whole network w.r.t. the base scenario. Results prove the effectiveness of the proposed routing control strategy in enhancing both mobility and environmental performance of the whole network w.r.t. the base scenario
Prevalence rate of Metabolic Syndrome in a group of light and heavy smokers
No full textBackground: Smoking is an important cause of morbidity and mortality worldwide. It is widely accepted as a majorrisk factor for metabolic and cardiovascular disease. Smoking reduces insulin sensitivity or induces insulin resistanceand enhances cardiovascular risk factors such as elevated plasma triglycerides, decreases high-density lipoproteincholesterol and causes hyperglycemia. Several studies show that smoking is associated with metabolicabnormalities and increases the risk of Metabolic Syndrome. The aim of this study was to estimate the prevalenceof the metabolic syndrome in a group of light and heavy smokers, wishing to give up smoking.Methods: In this cross-sectional study all the enrolled subjects voluntary joined the smoking cessation programheld by the Respiratory Pathophysiology Unit of San Matteo Hospital, Pavia, Northern Italy.All the subjects enrolled were former smokers from at least 10 years and had no cancer or psychiatric disorders, norhistory of diabetes or CVD or coronary artery disease and were not on any medication.Results: The subjects smoke 32.3 ± 16.5 mean Pack Years. The prevalence of the metabolic syndrome is 52.1%:57.3% and 44.9% for males and females respectively. Analysing the smoking habit influence on the IDF criteria forthe metabolic syndrome diagnosis we found that all the variables show an increasing trend from light to heavysmokers, except for HDL cholesterol. A statistical significant correlation among Pack Years and waist circumference(R = 0.48, p < 0.0001), Systolic Blood Pressure (R = 0.18, p < 0.05), fasting plasma glucose (R = 0.19, p < 0.005) and HDLcholesterol (R = −0.26, p = 0.0005) has been observed.Conclusions: Currently smoking subjects are at high risk of developing the metabolic syndrome.Therapeutic lifestyle changes, including smoking cessation are a desirable Public health goal and should successfullybe implemented in clinical practice at any age
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