1,720,972 research outputs found
Dynamic modeling and predictive control of a microfluidic system
Get PDFMicrofluidics, the study of fluids in microscopic channels, has led to important advances in fields as diverse as microelectronics, biotechnology and chemistry. Microfluidic research is primarily based on the use of microfluidic chips, low-cost devices that can be used to perform laboratory experiments using small amounts of fluid. These systems, however, require advanced control mechanisms in order to accurately achieve the flow rates and pressures required in the experiments. In this paper, we present the design of a model predictive controller intended to regulate the fluid flows in one of these systems. The results obtained, both through simulations and real experiments performed on the device, show that predictive control is an ideal technique to control these systems, especially taking into account all the existing constraints.12 pages, 17 figures. This is an author-approved English translation of a paper accepted for publication (see Related DOI
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
Análisis de identificabilidad aplicado a un sistema de transferencia de calor
No full text[Resumen] La identificabilidad es una propiedad esencial de los modelos dinámicos cuyo estudio debe ser abordado antes de iniciar cualquier procedimiento de estimación paramétrica. Sin embargo, este análisis generalmente ha sido ignorado en la literatura con unas pocas excepciones, como por ejemplo en el estudio de los sistemas biológicos. En este trabajo, se estudia la identificabilidad estructural de un sistema de transferencia de calor, con el fin de destacar la importancia de este análisis y animar a los investigadores a tenerlo en cuenta. Con este propósito, primero se presenta un modelo de parámetros concentrados basado en la analogía térmica-eléctrica. Después, se analiza la identificabilidad del modelo haciendo uso del teorema del isomorfismo local. A continuación, se presenta el análisis correspondiente a dos posibles escenarios distintos, en uno de ellos el estado se mide completamente mientras que en el otro sólo se dispone de medidas parciales. En el primer escenario se demuestra que la estructura paramétrica propuesta es identificable, lo que permite estimar los parámetros del sistema empleando datos xperimentales. El segundo escenario se corresponde con una situación no identificable, y sirve de ejemplo de lo que podría ocurrir si esta propiedad no es analizada.Este trabajo fue apoyado en parte por el Ministerio de Economía y Competitividad, Gobierno de España – Unión Europea, bajo el proyecto RTC-2017-5965-6, en parte por el Gobierno de Aragón – Unión Europea, bajo el proyecto DGA FSE T45 20R, y en parte por la Fundación Ibercaja - Universidad de Zaragoza, bajo el proyecto JIUZ-2021-TEC-05.Ministerio de Economía y Competitividad; RTC-2017-5965-6Gobierno de Aragón; DGA FSE T45 20RFundación Ibercaja; JIUZ-2021-TEC-0
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Model-free sliding-mode controller for soft landing of reluctance actuators
Get PDFSome electromagnetic actuators suffer from high velocity impacts during non-controlled switching operations, which cause contact bouncing, mechanical wear, and acoustic noise. Soft-landing control strategies aim at minimizing the impact velocities of these devices to improve their performance. This paper presents a sliding-mode controller for soft landing of single-coil reluctance actuators. It is a switching model-free controller, which results in a very simple implementation. A generalized dynamical hybrid model of an actuator is utilized for deriving the robustness condition, based on the Lyapunov theory. Then, the condition is evaluated for a dynamical model, based on a commercial device, and several reference trajectories. Finally, the controller performance is validated through simulations. The effect of the sampling rate on the resulting impact velocities is also analyzed
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