1,720,966 research outputs found
Comparative evaluation of three image analysis methods for angular displacement measurement in a MEMS microgripper prototype: A preliminary study
Full text linkThe functional characterization of MEMS devices is relevant today since it aims at verifying the behavior of these devices, as well as improving their design. In this regard, this study focused on the functional characterization of a MEMS microgripper prototype suitable in biomedical applications: The measurement of the angular displacement of the microgripper comb-drive is carried out by means of two novel automatic procedures, based on an image analysis method, SURF-based (Angular Displacement Measurement based on Speeded Up Robust Features, ADMSURF) and FFT-based (Angular Displacement Measurement based on Fast Fourier Transform, ADMFFT) method, respectively. Moreover, the measurement results are compared with a Semi-Automatic Method (SAM), to evaluate which of them is the most suitable for the functional characterization of the device. The curve fitting of the outcomes from SAM and ADMSURF, showed a quadratic trend in agreement with the analytical model. Moreover, the ADMSURF measurements below 1° are affected by an uncertainty of about 0.08° for voltages less than 14 V, confirming its suitability for microgripper characterization. It was also evaluated that the ADMFFT is more suitable for measurement of rotations greater than 1° (up to 30°), with a measurement uncertainty of 0.02°, at 95% of confidence level
A comparison among three different image analysis methods for the displacement measurement in a novel MEMS device
No full textThe functional characterization of MEMS devices is of great importance today, since it has the purpose both of verifying the behavior of these devices and of improving their future design. In this regard, the main topic of this study is the functional characterization of a microgripper prototype, a MEMS suitable in biomedical applications: to this aim, the measurement of the angular displacement of its comb-drive (capacitive electrostatic actuator that allows its movement) is provided by means of two novel automatic procedures, based on an image analysis software, the SURF-based (Speeded Up Robust Features) and the FFT-based (Fast Fourier Transform) method respectively. A preliminary comparison has been made, also with a previous semiautomatic method, to evaluate which of them is the best suitable for the functional characterization of the microgripper, highlighting their main advantages and limitations. The results obtained from the SURF-based method are promising; the curve obtained from the data showed a quadratic trend in agreement with both the analytical model and with the results obtained through the semiautomatic method. Moreover, the measurement obtained by the SURF-based method are affected by less than 0.2° uncertainty, that is less than one half of the measurement uncertainty due to the FFT-based algorithm
Architettura del sale
No full textIl progetto esposto è stato premiato dalla giuria internazionale composta da Thomas Herzog (presidente) Erik Bystrup, Glenn Murcutt, Nicola Marzot, Gianluca Minguzzi (segretario). la tesi insieme ai temi di riqualificazione paesaggistica proprone un progetto di allestimento per il riuso del magazzino del sale progettato da Pier Luigi Nervi
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
Transit time measurement of a pressure wave through an elastic tube based on LVDT sensors
No full textTransit time is the propagation time of a pressure wave travelling between two sites in a medium. Such parameter is mainly implied in the biomedical field as a surrogate for the estimation of important markers of the cardiovascular system (e.g. blood pressure and arterial stiffness). The non-invasive transit time measurement is commonly used in clinical practice because it allows the continuous recording and monitoring of blood pressure. The development of an in vitro system able to reproduce the main cardiovascular characteristics is of primary importance for further investigations of the relationship between transit time and the arterial stiffness in order to predict the cardiovascular risk factors. The present work focuses on the development of a LVDT-based experimental set-up able to simulate transit time variations due to transmural pressure changes on an elastic tube. As validated in in vivo measurements, transit time and maximum radial tube displacement increment decrease with decreasing transmural pressure
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
Functional characterization of MEMS Microgripper prototype for biomedical application: Preliminary results
No full textMicrogrippers are MEMS technology-based devices, able to handle objects of dimensions similar to those of cells (i.e. between 10 and 100 μm); these particular devices, are able to move and grasp object positioned between their grippers when a voltage is applied. In recent years, the demand for low-invasive, reliable, low-energy, small-sized devices with high performance repeatability is growing, and microgrippers seem to satisfy these expectations and are very promising in biomedical applications. However, the contributions relating to the characterization of such devices are still lacking, both from the metrological and performance point of view. In this study a methodology to characterize a microgripper prototype for biomedical applications is proposed, that includes the analysis of images through an in-house software developed ad hoc, acquired through a light trinocular microscope and an embedded camera. In particular, the Comb-Drive angular displacement, gripper rotation and the gripper displacement due to applied voltage have been measured. The results gave an estimate of the total uncertainty of 0.021°, 0.09° and 4 μm for Comb-Drive angular displacement, gripper rotation and gripper displacement respectively, referred to the whole range of the applied voltage
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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