1,720,979 research outputs found
Multiphysics modelling of high-speed optoelectronic devices for silicon photonics platforms
Full text linkL'abstract è presente nell'allegato / the abstract is in the attachmen
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
Interfacial Charge Dynamics in Metal-Oxide–Semiconductor Structures: The Effect of Deep Traps and Acceptor Levels in GaN
Full text linkUsing numerical simulations, we investigate the effects of deep traps and deep acceptor levels in magnesium-doped GaN on interface charges in the semiconductor-oxide interface. Specifically, in this work we address two open issues observed in experimental studies on GaN trench metal-oxide semiconductor field-effect transistors. (i) We investigate the observed clockwise hysteresis in the transfer characteristics and elucidate the underlying physical mechanism causing it. By employing appropriate models for substitutional carbon at nitrogen sites (CN ) and nitrogen vacancies (VN ), we calculate the hysteresis dependence on the trap concentrations and the measurement sweep duration Ts. We show that CN acceptor traps in p-GaN are likely responsible for this phenomenon and the largest hysteresis is predicted for a sweep duration of Ts ≈ 30 s. (ii) We also address the apparent inconsistency between the experimental and theoretically predicted magnesium-ionization levels and the variations of the measured transfer characteristics, specifically the threshold voltage. We show that the bands bending in the channel area creates a layer in which magnesium iss completely ionized. As a result, the magnesium partial ionization does not have an effect and, while the threshold voltage decreases, nor does the breakdown voltage, as observed experimentally. The measured threshold voltage, which is lower than the theoretically predicted value, is
caused by fixed and trapped charges at the interface, in agreement with values reported in the literature
MQTTSA: A Tool for Automatically Assisting the Secure Deployments of MQTT Brokers
No full textThe Internet of Things (IoT) is radically changing the way people live and interact with society: ranging from wearables to smart cities, the number of IoT devices has grown exponentially. The Message Queuing Telemetry Transport (MQTT) protocol is one of the most widely used IoT communication protocols. However, our investigation over publicly available MQTT endpoints confirms an alarming trend, i.e. many do not provide adequate security measures and often rely on the insecure default configuration. To improve the security awareness on the use of MQTT the paper presents MQTT Security Assistant (MQTTSA), a tool that automatically detects misconfigurations in MQTT-based IoT deployments. To assist IoT system developers, MQTTSA produces a report outlining detected vulnerabilities, together with (high level) hints and code snippets to implement adequate mitigations. The effectiveness of the tool is assessed by a thorough experimental evaluation
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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