1,720,995 research outputs found
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
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
All-Optical Quantum Information Processing in the Ultrafast Regime
No full textQuantum computing offers a promising pathway to solving problems that are intractable for classical computers. Despite recent progress, the development of a scalable quantum information processor remains an open challenge. Several hardware platforms remain contenders; however, photonic systems have emerged as a strong candidate due to their ability to operate at room temperature and exceptional resilience to decoherence. State-of-the-art photonic quantum processors use path encoding, which often requires an exponentially increasing number of optical components, making these schemes unavoidably large or lossy in some cases. Time-bin encoding has recently proven to be a promising method to reduce the number of optical components in a photonic quantum processor by enabling operation along a single optical path. Yet, a major barrier to the widespread adoption of time-bin encoding is the challenge of maintaining phase stability across the entire device for extended periods of time. We overcome this obstacle here, by introducing a promising new contender in the photonic quantum computing landscape: ultrafast time-bin encoding.
The architecture proposed in this thesis encodes quantum information in the arrival time of photons on ultrafast timescales, processed using optically induced nonlinearities via Kerr gating and birefringent media. A major part of this thesis is the development of the optical Kerr gating technique, which is explored in three initial studies. We first introduce a characterization method, which also happens to enable the carving of ultrashort pulses from a continuous wave laser. With this technique, we demonstrate configurable all-optical Kerr gating down to a temporal resolution of 305 fs. We next investigate translating this high temporal resolution to the frequency domain, using our Kerr gate to measure time-stretched spectra. Finally, we employ two Kerr gates for measurement of the temporal profiles of entangled photons, subsequently allowing for verification of entanglement. Each of these studies provides valuable insight into the optimal operation of the Kerr gate for quantum information processing.
The Kerr gate is then deployed for the demonstration of our ultrafast time-bin encoding scheme. Operating first in the single photon regime, we implement both a specific quantum algorithm and a more generalized, programmable circuit. Within the large multimode interferometers presented in these two implementations, we see remarkable phase stability over extended periods of time, high fidelity operation, and low loss - all key ingredients for scalability in quantum information processing. Finally, these capabilities are extended to include multiphoton operation, which is a crucial requirement for any photonic quantum information processing system. Taken together, these results demonstrate the potential of ultrafast time-bin encoding for the development of scalable photonic quantum information processing
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
Characterization and Modification of Fiber-based Photon Pair Sources
No full textNon-classical light sources are a fundamental building block of quantum photonic technologies. As these photonic technologies require higher numbers of sources and more specific source properties, it becomes increasingly important to characterize and manipulate these sources effectively. This thesis consists of three main projects, all relating to non-classical sources of light. First, we present a method for the rapid measurement of the joint spectral intensity of fiber-based photon pair sources. This method extends the concept of Stimulated Emission Tomography, using a chirped, broadband seed beam to stimulate the four wave mixing interaction. The use of the broadband seed, generated through supercontinuum generation, allows for measurements on the few second timescale and requires only a single pump laser to achieve high resolution joint spectra.
In the second project, we use this characterization tool to test a variety of different fiber-based photon pair sources. We use three different modification approaches (bending, squeezing, and tapering) to induce changes in the joint spectral properties of the photon pair sources. We show that each of these modifications has some impact on the joint spectra measured. The resulting joint spectra are very complex, highlighting the importance of performing measurements rather than relying on calculations alone.
Lastly, we demonstrate a fast switch for the manipulation of single photons. The switch uses the optical Kerr effect to rotate the polarization state of single photons at ultrafast timescales. The implementation of this switch is experimentally straightforward, using a commercial, single mode fiber as the Kerr medium and nJ level pump powers. We operate at an 80 MHz repetition rate and measure 97% switching efficiency, picosecond level switching speed, and approximately 800:1 signal to noise ratio from the operation
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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