1,720,954 research outputs found
Thermal Phase Shifters for Femtosecond Laser Written Photonic Integrated Circuits
Get PDFPhotonic integrated circuits (PICs) are today acknowledged as an effective solution to fulfill the demanding requirements of many practical applications in both classical and quantum optics. Phase shifters integrated in the photonic circuit offer the possibility to dynamically reconfigure its properties in order to fine tune its operation or to produce adaptive circuits, thus greatly extending the quality and the applicability of these devices. In this paper, we provide a thorough discussion of the main problems that one can encounter when using thermal shifters to reconfigure photonic circuits. We then show how all these issues can be solved by a careful design of the thermal shifters and by choosing the most appropriate way to drive them. Such performance improvement is demonstrated by manufacturing thermal phase shifters in femtosecond laser written PICs (FLW-PICs), and by characterizing their operation in detail. The unprecedented results in terms of power dissipation, miniaturization and stability, enable the scalable implementation of reconfigurable FLW-PICs that can be easily calibrated and exploited in the applications
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Design and fabrication of a four-arm integrated photonic interferometer for quantum enhanced multiphase estimation
Get PDFLAUREA MAGISTRALELo scopo di questa tesi è quello di disegnare, fabbricare e caratterizzare un interferometro fotonico integrato a quattro braccia. Questo disposivito, composto dalla cascata di due diversi splitter a quattro porte chiamati quarter, è scritto in un substrato di vetro tramite la tecnica della Femtosecond Laser Micromachining (FLM). Questa ci permette di ottenere una grande flessibilità nel design e un'ottima stabilità del circuito. In entrambi i circuiti, 6 parametri interni possono essere attivamente controllati attivando degli sfasatori termo-ottici. Questa alta riconfigurabilità permette al dispositivo di essere usato sia per misure super risolute a singolo parametro che per implementare algoritmi di stima multi-fase, con una precisione che supera lo Standard Quantum Limit.In this thesis work, we present the fabrication and the full characterization of the components required for the realization of an integrated photonic multimode interferometer. In particular, two distinct 4-modes coherent optical splitters (quarters) are fabricated in two glass substrates by means of femtosecond laser waveguide writing. Interestingly, this fabrication techniques allows for a three-dimensional prototyping of the devices, that can therefore be fabricated in a simple and cost-effective fashion. The optical characterization of the quarters testified their correct functioning, with an average power division of 25% +- 0.16% among all possible input-output channels. Each of the two optical chips incorporate six thermo-optics phase shifters, for both ensuring a balanced phase-operation of the quarters, and for the active manipulation of all the internal phases of the interferometer. Each phase shifter allows to provide a full 2pi modulation on its optical mode with a maximum power dissipation of 500 mW, and with reduced cross talks to the other modes. As it will be discussed thorough the thesis, the realization of these low-loss and reliable quarters required to improve beyond the state of the art both the optical circuit inscription and the micro-heaters deposition processes. The devices presented can be considered ready for being combined by butt coupling and glued, in order to complete the realization of a four-modes reconfigurable interferometer. We expect that this device will have a strong impact in the field of quantum metrology, as it enables the robust benchmarking of several protocols of quantum multi-parameters estimation, with a precision beyond the Standard Quantum Limit
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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