1,720,956 research outputs found
Monolithically integrated 16-channel 1.55 mu m pin/HBT photoreceiver array with 11.5 GHz bandwidth
No full textA 16-channel InP-based (lambda similar or equal to 1.55 mu m) monolithically integrated photoreceiver array is realised with an average channel bandwidth of 11.5GHz and adjacent channel crosstalk of < -35dB with both dual bias design and the incorporation of metal shields
High speed monolithically integrated p-i-n/HBT photoreceivers
No full textThe characteristics of high-performance InP-based monolithically integrated single and multiple channel photoreceivers with an InGaAs p-i-n photodiode and InAlAs/InGaAs HBTs, realized by one-step molecular beam epitaxy, are described. The monolithically integrated photoreceiver includes an integrated spiral inductor following the p-i-n diode at the input of the transimpedance amplifier to enhance the circuit response at high frequencies. Crosstalk of the multi-channel photoreceiver arrays is greatly reduced by applying both a metal ground shield and dual bias. The maximum measured -3 dB bandwidth of a single-channel integrated p-i-n/HBT photoreceiver is 19.5 GHz and the minimum crosstalk of the photoreceiver arrays, with an individual channel bandwidth of 11.5 GHz, is -36 dB. At these performance levels, these OEICs represent the state-of-the-art in multichannel integrated photoreceiver arrays
Investigation of adjacent channel crosstalk in multichannel monolithically integrated 1.55 mu m photoreceiver arrays
No full textWe have investigated adjacent channel crosstalk in 3-, 8-, and 16-channel InP-based monolithically integrated p-i-n/HBT photoreceiver arrays, with a channel bandwidth of 11 GHz, By using a novel monolithically integrated radiation shield, we have been able to reduce the crosstalk to -35 dB at 10 GHz, These parameters represent the best performance in multichannel integrated photoreceiver arrays, The two main components of crosstalk are found to be radiation crosstalk and electrical crosstalk and these are separately dependent on interchannel spacing and single-or dual-source biasing schemes. A electromagnetic full-wave solution shows that the measured crosstalk in arrays without the radiation shield could be dominated by radiation crosstalk, which can be modeled as a capacitive coupling between adjacent channels, Similarly, electrical crosstalk can be modeled by equivalent parasitic resistive and inductive elements, Values of these circuit elements have been determined by analyzing experimental data.Defense Advanced Research Projects Agency (COST) Grant MDA 972-94-1-0004, and the U.S. Army Research Office (URI program) Grant DAAL03-92-G-010
InP-based MMIC components for an optical phase-locked loop
No full textGilbert-cell and photoreceiver circuits were designed for an integrated optical phase-locked loop (OPLL) to generate stable channel offsets in dense wavelength-division multiplexing (DWDM). These circuits were fabricated using a p-i-n/heterojunction bipolar transistor layer structure. Various configurations of an OPLL employing Gilbert-cell phase detectors and photoreceiver circuits were tested, and wavelength separations from 1.0 to beyond 27.11 GHz were obtained.Army Research Office AASERT Progra
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
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