1,721,033 research outputs found
Fully differential operational amplifier
No full textA fully differential operational amplifier is provided. The amplifier has input nodes and includes a differential input stage for receiving input signals over the input nodes and providing output signals on first and second intermediary nodes. The amplifier includes a fully differential amplification stage having positive and negative inputs coupled to the first and second intermediary nodes, respectively. The amplifier includes a first compensation transistor having conduction terminals coupled to the first intermediary node and a first node, and a control terminal coupled to a negative output of the fully differential amplification stage. The amplifier includes a second compensation transistor having conduction terminals coupled to the second intermediary node and a second node, and a control terminal coupled to a positive output of the fully differential amplification stage. The amplifier includes positive and negative output stages for providing amplifier outputs and feeding the outputs back to the amplifier
A fault identification technique for FBG sensors embedded in composite structures
No full textThe paper proposes a method for the identification of sensor faults, that can be applied in those vibration control applications where large arrays of sensors are used. Indeed, distributed measurement proves to be very effective in recognizing and suppressing the contribution of different modes to structure vibrations, but its efficiency is dramatically reduced if one or more sensors do not work correctly. This is the case, for example, of fiber Bragg grating sensor chains. For this reason, a sensor fault identification algorithm is introduced. This method, based on the analysis of the residuals of the measurement estimation, allows to identify different typologies of sensor fault or malfunctioning, such as complete fault or additive and multiplicative measurement errors. Once identified, these sensors can be excluded from the feedback loop of the control algorithm in order to avoid unwanted behaviors or instabilities. Numerical and experimental tests have been carried out on a carbon fiber structure considering different fault conditions. Results show that it is possible to identify the faulty sensors and thus improve the signals used in the feedback loop
A Low-Power Sigma-Delta Modulator for Healthcare and Medical Diagnostic Applications
Full text linkThis paper presents a switched-capacitor Sigma-Delta modulator designed in 90-nm CMOS technology, operating at 1.2-V supply voltage. The modulator targets healthcare and medical diagnostic applications where the readout of small-bandwidth signals is required. The design of the proposed A/D converter was optimized to achieve the minimum power consumption and area. A remarkable performance improvement is obtained through the integration of a low-noise amplifier with modified Miller compensation and rail-to-rail output stage. The manuscript also presents a set of design equations, from the small-signal analysis of the amplifier, for an easy design of the modulator in different technology nodes. The Sigma-Delta converter achieves a measured 96-dB dynamic range, over a 250-Hz signal bandwidth, with an oversampling ratio of 500. The power consumption is 30 μW, with a silicon area of 0.39 mm2
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
A PROCEDURE TO EVALUATE RELIABILITY OF MEASUREMENTS IN A SMART STRUCTURE
No full textFiber optic strain sensors, such as Fiber Bragg Gratings (FBG), have a great potential in the use in smart structures thanks to their small transversal size and the possibility to make an array of many sensors. They can be embedded in carbon fiber structures and their effect on the structure is nearly negligible. This paper introduces the use of these sensors to increase the reliability of feedback measurements in smart structures designed to actively control vibrations. As known, one of the main drawbacks of these structures is the robustness of the control when one or more sensors do not work properly. In these cases the performance in reducing vibration can be seriously limited and problems of instability may occur. The use of FBG sensors can overcome this limit thanks to the large number of available measurements. This paper introduces some different control algorithms to suppress vibration and discusses the reliability of feedback measurements when failures on sensors happened. Theoretical results are supported by experimental tests on a large flexible system made of a thin cantilever beam with 14 longitudinal FBG sensors and three piezoelectric actuators (PZT)
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
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