1,721,104 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
Nonlinear Behavioral Balancing by Extension of Lie Semigroups
Full text linkPreviously, a balancing condition for nonlinear systems was introduced. This paper provides an extended justification of such balancing condition in terms of semigroups of diffeomorphisms in a Hilbert submanifold framework. Moreover, it is argued that when such condition is satisfied the resulting group of diffeomorphisms describes the flow of the nonlinear system. Using the same framework the nonlinear behavioral operator is defined and a result regarding its spectral properties is presented
Towards Power-Based Control Strategies for a Class of Nonlinear Mechanical Systems
No full textIn the present work we are interested on the derivation of power-based passivity properties for a certain class of non-linear mechanical systems. While for general mechanical systems, it is of common use to adopt a storage function related to the system’s energy in order to show passivity and stabilize the system on a desired equilibrium point (e.g., IDA-PBC), we want here to obtain similar properties related to the system’s power. The motivation arises from the idea that in some engineering applications (satellite orbit motion, aircraft dynamic, etc...) seems more sensible to cope with the power flowing into the system instead of the energy that, for stabilization purposes, means to consider the systems’s equilibrium the state for which the energy flow-rate (i.e.,system’s power) achieve its minimum. In this respect, we recall first the power-based description for a certain class of (non)-linear mechanical systems and then we give sufficient conditions to obtain power-based passivity properties, provided a suitable choice of port-variables. We conclude with the example of the inverted pendulum on the cart
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
Towards Power-Based Control Strategies for a Class of Nonlinear Mechanical Systems
Full text linkIn the present work we are interested on the derivation of power-based passivity properties for a certain class of non-linear mechanical systems. While for general mechanical systems, it is of common use to adopt a storage function related to the system’s energy in order to show passivity and stabilize the system on a desired equilibrium point (e.g., IDA-PBC), we want here to obtain similar properties related to the system’s power. The motivation arises from the idea that in some engineering applications (satellite orbit motion, aircraft dynamic, etc...) seems more sensible to cope with the power flowing into the system instead of the energy that, for stabilization purposes, means to consider the systems’s equilibrium the state for which the energy flow-rate (i.e.,system’s power) achieve its minimum. In this respect, we recall first the power-based description for a certain class of (non)-linear mechanical systems and then we give sufficient conditions to obtain power-based passivity properties, provided a suitable choice of port-variables. We conclude with the example of the inverted pendulum on the cart
Towards Power-Based Control Strategies for a Class of Nonlinear Mechanical Systems
Full text linkIn the present work we are interested on the derivation of power-based passivity properties for a certain class of non-linear mechanical systems. While for (non)-linear mechanical systems, it is of common use to adopt a storage function related to the system’s energy in order to show passivity and stabilize the system on a desired equilibrium point (e.g., IDA-PBC), we want here to obtain similar properties related to the system’s power. The motivation arises from the idea that in some engineering applications (satellite orbit motion, aircraft dynamic, etc...) seems more sensible to cope with the power flowing into the system instead of the energy that for stabilization purposes, means to consider the systems’s equilibrium the state for which the energy flow-rate (i.e.,system’s power) is minimal. In this respect, we recall first the power-based description for a certain class of (non)-linear mechanical systems and then we give sufficient conditions to obtain power-based passivity properties, provided a suitable choice of port-variables. We conclude with the example of the inverted pendulum on the cart
Power Shaping Control of Nonlinear Systems:A Benchmark Example
No full textIt is well known that energy balancing control is stymied by the presence of pervasive dissipation. To overcome this problem in electrical circuits, the authors recently proposed the alternative paradigm of power shaping—where, as suggested by its name, stabilization is achieved shaping a function akin to power instead of the energy function. In this paper we extend this technique to general nonlinear systems and apply it for the stabilization of the benchmark tunnel diode circuit. It is shown that, in contrast with other techniques recently reported in the literature, e.g. piece–wise approximation of nonlinearities, power shaping yields a simple linear static state feedback that ensures (robust) global asymptotic stability of the desired equilibrium
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