1,720,958 research outputs found
Measurement of biomechanical response and trasmissibility along the hand-arm system by laser Doppler techniques
No full textThe apparent mass and mechanical impedance of the hand and the transmission of vibration to the fingers, hand, and arm
No full textAlthough hand-transmitted vibration causes injury and disease, most often evident in the fingers, the biodynamic responses of the fingers, hand, and arm are not yet well understood. A method of investigating the motion of the entire finger–hand–arm system, based on the simultaneous measurement of the biodynamic response at the driving point and the transmissibility to many points on the finger–hand–arm system, is illustrated. Fourteen male subjects participated in an experiment in which they pushed down on a vertically vibrating metal plate with their right forearm pronated and their elbow bent at 90°. The apparent mass and mechanical impedance of the finger–hand–arm system were measured for each of seven different contact conditions between the plate and the fingers and hand. Simultaneously, the vibration of the fingers, hand, and arm was measured at 41 locations using a scanning laser Doppler vibrometer. Transmissibilities showed how the vibration was transmitted along the arm and allowed the construction of spectral operating deflection shapes showing the vibration pattern of the fingers, hand, and arm for each of the seven contact conditions. The vibration patterns at critical frequencies for each contact condition have been used to explain features in the driving point biodynamic responses and the vibration behaviour of the hand–arm system. Spectral operating deflection shapes for the upper limb assist the interpretation of driving point biodynamic responses and help to advance understanding required to predict, explain, and control the various effects of hand-transmitted vibratio
Topological classification of small DC motors
No full textIn this paper we propose a new methodology based on signal embedding and applied topology for studying real noisy signals. Even if signal embedding is a useful tool, it is not sufficient for studying long range noisy signals. We argue that embedded signal in m space can be properly analysed with topology based techniques. We obtained numerical evidences that our procedure properly classifies small DC motors into good/faulty, using the vibration data acquired from the bench. Small DC motors are largely employed in automotive to drive fans in HVAC (Heating, Ventilation and Air Conditioning) systems. Because of their high-speed, they can produce noise and vibration, perceived by the final users as a lack of quality. This problem is becoming relevant with the advent of the hybrid vehicles, in which the electrical motor is completely silent if compared to a traditional internal combustion engine, so all other noise and vibration source become noticeable by the passengers and felt as discomfort or a nuisanc
Structural health monitoring applications with wireless sensors on an historical masonry building
No full textIn the last decades, the need for an effective seismic protection and vulnerability reduction of cultural heritage buildings and sites determined a growing interest in Structural Health Monitoring (SHM) as a knowledge-based assessment tool to quantify and reduce uncertainties regarding their structural performance. Monitoring can be successfully implemented in some cases as an alternative to interventions or to control the medium- and long-term effectiveness of already applied strengthening solutions.
Traditional monitoring systems are composed of grids of sensors distributed along the structure to be monitored and connected to a central acquisition and processing unit through cables, and then post-processed in order to determine structure’s condition and assess a safety level. Recently, the use of wireless sensor networks (WSN) as an alternative base infrastructure for structural monitoring systems has been explored. A wireless sensor network is usually a more flexible solution (in facts, it does not require any cable deployment if the nodes are battery powered) with minor costs associated especially if the network is composed by low cost devices (e.g., MEMS sensors). Respect to a wired solution, new problems should however be considered: the synchronization between sensor nodes, the short transmission distance, the optimization of energy consumption and the selection of adequate low-cost sensors.
In this framework, this work details the main results obtained in the context of the “Palazzo Comunale of Castelfidardo” monitoring project with WSN, with the aim to get an accurate numerical model that simulates the dynamic behaviour of the whole structure.
A comparison between the structural responses obtained from the preliminary and an updated numerical model is proposed
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
Measurement of biomechanical response and trasmissibility along the hand-arm system by laser Doppler techniques
No full textVariations 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
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