1,721,184 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
Ultracapacitor Degradation State Diagnosis via Electrochemical Impedance Spectroscopy
No full textIn this paper, we propose the use of the electrochemical impedance spectroscopy technique for state diagnosis of electric double-layer ultracapacitors. Ultracapacitors under investigation are Maxwell BCAP 0350 and they were stressed in several ways for our study. The analyzed stress conditions include accelerated aging tests, overvoltage, and over temperature tests. Chemical and physical effects on supercapacitor materials are pointed out through a morphologic analysis implemented by means of an environmental scanning electron microscope and a chemical composition analysis obtained by means of an energy dispersive spectrometer. Consequent degradation effects are described in terms of frequency behavior of equivalent circuital parameters
Characterization of a low-cost and low-power environmental monitoring system
No full textIoT is a revolutionary technology that represents the future of computing and communications. The paper focuses on the characterization of a Wireless Sensor Network used for smart agriculture, which is one of the new frontiers of IoT. Smart farming is the application of information and data technologies for optimizing complex farming systems. WSNs are widely used to measure agri-related information like temperature, humidity, solar radiation, presence of pollution and so on. In this paper the design of a wireless mesh network composed by low cost and low power system-on-a-chip is presented dealing with the frequently encountered issues of wireless networks. In particular, this work proposes a framework for the characterization of customized devices designed for monitoring networks: different types of test are performed in order to analyze the behavior of the components. The work focuses on the maximum coverage distance which is a critical parameter in agriculture field since the largeness of the involved area; it also deals with the thermal characterization to improve reliability performances and ADC calibration to ensure high accuracy of the acquired data. Moreover, the paper pays great attention on the power consumption of the sensor node, in fact the minimization of the current consumption of the nodes is a mandatory requirement to ensure low maintenance costs
L'approccio previsionale dell'affidabilità - Modelli e banche dati
No full textdopo aver parlato in un precedente lavoro di prove di affidabilità che possono essere eseguite in laboratorio utilizzando adeguata strumentazione, in questo articolo ci soffermiamo sul calcolo previsionale e quindi come valutare il tasso di guasto di componente e di sistema ricorrendo all'impiego delle banche dat
A hybrid tree sensor network for a condition monitoring system to optimise maintenance policy
No full textWind energy is the leading candidate among renewable energy sources as an alternative to burning fossil fuels. A proper and accurate condition monitoring plan is necessary to ensure the high reliability and availability required by energy production systems. This article proposes a wireless mesh network to implement a widely distributed condition monitoring system for a wind farm. Using different types of sensor, the condition monitoring system evaluates the health state of each turbine. The aim of the work is to propose an architecture that can identify possible incipient failures in the most critical turbine's components. Using this system, it is possible to guarantee continuity of service minimising the unplanned maintenance operation due to hidden failure
Condition monitoring of wind farm based on wireless mesh network
No full textSince the last years of twentieth century the use of wind energy rapidly increased and it is imposed as one of the best alternatives to burning fossil fuels. Nowadays, in renewable energy resources, wind energy is the leading candidate for electricity production due to its lower investment cost and well-developed technology in manufacturing high-power wind turbines. Basing on a Reliability Centred Maintenance (RCM) analysis, this paper focuses on the use of a Wireless Mesh Network in order to monitoring several condition parameters to identify possible incipient failures analysing the health-status of the turbine. The objective of the RCM is to identify the appropriate maintenance task for each item. Condition Monitoring is one of the possible task choices and represents a cost-effective solution to minimize the plant downtime. The case study identifies the most critical components of wind turbine and propose a set of possible sensors that could be included in the Wireless Mesh Network to monitor the condition parameters of the turbine
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