1,721,078 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
Improving the efficiency of fibre-chip grating couplers near 1310 nm
No full textWe present our recent work on fibre-chip grating couplers operating around 1310 nm. For the first time, we demonstrated the combination of dual-etch and apodization design approaches which can offer state of the art performance. Initial tests from fabricated structures show a -2.2dB loss
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
Coarse wavelength division (de)multiplexer using an interleaved angled multimode interferometer structure
Full text linkWe have demonstrated a coarse wavelength (de)multiplexing structure on the silicon-on-insulator platform. It comprises two 4-channel angled multimode interferometers interleaved with an imbalanced Mach-Zehnder interferometer (MZI) leading to an 8-channel multiplexing device. The device requires only single lithography and etching steps for fabrication and has a good tolerance to fabrication errors in terms of waveguide width. The insertion loss and crosstalk achieved are 3-4 dB and -(15-20) dB, respectively. Potential is shown for achieving improved performance using larger waveguide bending radii in the MZI arms and/or (a) local heater(s) for refractive index tuning
The evolution of angled MMI structure on the SOI platform
No full textThe angled multimode interferometer (AMMI) was recently demonstrated as a wavelength division (de)multiplexing (WDM) structure employing the phenomenon of dispersive self-imaging in a multimode planar waveguide. It has distinct advantages including very low insertion loss, ease of fabrication and good tolerance to fabrication error. Here, we first demonstrated a further optimized single 4-channel AMMI on the silicon-on-insulator (SOI) platform with a low insertion loss of < 1 dB, a low cross talk of < -23 dB and a non-uniformity of < 0.5 dB. However, a single AMMI is limited to have small channel count with a relatively large channel spacing in order to maintain high-performance WDM functionality. Therefore we subsequently demonstrated two structures derived from a single AMMI on the SOI platform: An 8-channel WDM comprising of two 4-channel AMMIs interleaved by an imbalanced Mach-Zehnder interferometers (MZIs) was fabricated. Low-insertion-loss and low-cross-talk operation was achieved without active tuning structures
Temperature insensitive racetrack resonators for near infrared applications
No full textOptical Fiber Communication Conference Los Angeles OTh4D.5 4-8 Mar We report a record low temperature dependent wavelength shift of 0.2 pm/K for silicon-on-insulator strip racetrack resonators at a 1550 nm wavelength using a polymer cladding. A significant reduction of propagation losses is also achieved
A robust and fabrication tolerant (de)multiplexer on the SOI platform
No full textWe recently demonstrated the angled multimode interferometer (AMMI) as a wavelength (de)multiplexer for 4 channels. We have now extended the device application to eight channels via interleaving, and we propose denser integration via ring resonator enhancement
- …
