1,720,997 research outputs found
Cooperative driving: A comprehensive perspective, the role of communications, and its potential development
Full text linkInter-vehicle communications may have many reasons to be, but improving road safety and efficiency is arguably the only reason that may differentiate them from other communication infrastructures and justify a special effort in their study and deployment. This work overviews (some of) the past research on the topic to draw some lessons for the future, and tries to dissipate some of the fog that still veils the future of cooperative and autonomous vehicles: Can communications improve mobility or selfish-autonomous vehicles will dominate roads in the future? The paper is not a survey, but rather a critical analysis of what Cooperative Driving (CD) means and how communication is essential for some functions and useful for others, never detrimental. We dedicate a special part to platooning, as iconic application of CD, one of the most studied and also closer to be market ready, at least technologically. A final section discusses the potentialities of CD and what threatens its adoption
Grain growth in spinel and plagioclase peridotites: a time-resolved experimental study on textural evolution
No full textDriving under influence: Robust controller migration for MEC-enabled platooning
No full textConnected cars are becoming more common. With the development of multi-access edge computing (MEC) for low-latency applications, it will be possible to manage the cooperative adaptive cruise control (CACC, also known as platooning) of such vehicles from the edge of cellular networks. In this paper, we present a controller that manages platooning from the network edge by adapting to varying network conditions. We incorporate a mechanism in the controller that allows vehicles to switch to automated cruise control when delays exceed safety thresholds, and back to platooning when the delays are sufficiently low to support it. We also formulate the problem of maintaining a low-latency connection in the presence of high mobility through migration, and propose a Q-Learning algorithm to solve this problem. We finally propose an Asynchronous Shared Learning scheme that enables multiple migration agents to cooperate, in order to expedite the convergence of migration policies. Compared to state-of-the-art migration techniques, our scheme exhibits better compliance of vehicle speed and spacing values to preset targets, and ameliorates statistical dispersion
Sonographic diagnosis of congenital anomalies during the first trimester
No full textCurrent ultrasound technology allows an examination of fetal anatomy and the detection of anomalies at 12-15 weeks. Studies assessing the accuracy of early sonographic diagnosis prior to 15 weeks of pregnancy were reviewed. In expert hands the detection rate is about 40 per cent for major extra-cardiac anomalies and 65 per cent for major cardiac defects. However, due to technical and practical limitations, sonographic assessment of fetal anatomy in the first trimester cannot replace the midtrimester scan and should be restricted to couples whose fetus is at increased risk for malformation
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
On the Progressive Introduction of Heterogeneous CACC Capabilities
Full text linkCan we introduce Cooperative Adaptive Cruise Control (CACC) technologies on the road without separated road infrastructures? This simple question is often latent in works dealing with cooperative driving, especially in feasibility analysis of cooperative driving. As of today, the question has indeed received no definitive answer in the literature because it is hard to model analytically heterogeneous systems or to experiment with them. This work helps understanding how vehicles interact among each others when they do not run a single, a-priory defined, CACC algorithm, but rather each vehicle adopt its own one. We introduce the concept of mixed platoon, i.e., a string of vehicles where more than one CACC algorithm is used, and we experiment with mixed platoons in silico to study how the mixture of CACC algorithms affects efficiency and safety. For instance we analyze scenarios where we progressively introduce homogeneous and mixed platoons among standard Adaptive Cruise Control (ACC) vehicles, quantifying the positive or negative effects on traffic efficiency and safety induced by the introduction of CACC technologies as a function of their penetration rate. The obtained results encourage additional research on the topic, starting from theoretical analysis of mixed platoons down to performance evaluations of actual implementations
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
- …
