1,721,300 research outputs found
On the fixed-time consensus problem for nonlinear uncertain multiagent systems under switching topology
No full textThis article proposes a novel local interaction rule providing leader-following and leader-less consensus in a network of nonlinear uncertain first-order agents communicating through a connected and switching graph topology. Particularly, the proposed interaction rule guarantees that consensus is achieved after a finite settling time, which admits an upper bound independent of the initial conditions of the agents' states. This property, called fixed-time convergence, is achieved, thanks to homogeneous polynomial terms of suitable order in the local interaction rule. A Lyapunov-based analysis is presented to support the convergence features of the proposed interaction protocol. Simulation results are presented in order to corroborate the theoretical findings
Topo-Iberia project: CGPS crustal velocity field in the Iberian Peninsula and Morocco
No full textGarate, J., Martin-Davila, J., Khazaradze, G., Echeverria, A., Asensio, E., Gil, A.J., de Lacy, M.C., Armenteros, J.A., Ruiz, A.M., Gallastegui, J., Alvarez-Lobato, F., Ayala, C., Rodríguez-Caderot, G., Galindo-Zaldívar, J., Rimi, A., Harnafi, M
Continuous and discrete state reconstruction for nonlinear switched systems via high-order sliding-mode observers
No full textA class of nonlinear switched systems is studied, and a finite-time converging state observer is proposed.
The observer strategy, based on the high-order sliding-mode approach, is able to reconstruct both the continuous
and discrete states of the switched system based on output measurements and on the knowledge of the set of
possible system’s dynamics. All the ‘operating modes’ of the switched system are required to satisfy certain
observability-like and boundedness restrictions. The observer provides a finite-time converging estimate and,
after a switching of the active mode, it features an arbitrarily fast transient to recover the correct (continuous and
discrete) state estimate. A numerical example illustrates the performance of the proposed observer
Bubbling solutions for supercritical problems on manifolds
No full textLet (M,g) be an n-dimensional compact Riemannian manifold without boundary and Γ be a non-degenerate closed geodesic of (M,g). We prove that the supercritical problem. -δgu+hu=un+1n-3±ε,u>0, in (M,g) has a solution that concentrates along Γ as ε goes to zero, provided the function h and the sectional curvatures along Γ satisfy a suitable condition. A connection with the solution of a class of periodic Ordinary Differential Equations with singularity of attractive or repulsive type is established
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
- …
