1,354,189 research outputs found
5 × 5 25 Gbit/s WDM-MDM
Get PDFWavelength-division multiplexed-passive optical network (WDM-PON) is a revolutionary high-capacity and scalable broadband access network. This paper capitalizes on Laguerre–Gaussian (LG) modes to reduce modal dispersion and increase data capacity. A data rate of 25 Gbit/s is attained for a multimode fiber link by multiplexing five LG modes on five wavelengths centered at 1,550.12 nm for a distance up to 800 m
Multidiameter optical ring and Hermite–Gaussian vortices for wavelength division multiplexing–mode division multiplexing
Get PDFOptical vortices are high-capacity data carriers for mode division multiplexing (MDM) in multimode fiber (MMF). This paper reports on the MDM of a combination of helical-phased optical vortices comprising donut modes and Hermite–Gaussian (HG) modes for different radial offsets from the MMF axis. A data rate of 44 Gbps is achieved for wavelength division multiplexing–MDM of two pairs of helical-phased donut mode and HG mode at wavelengths 1550.12 and 1551.72 nm for a MMF length of 1500 m
The role and challenges of free-space optical systems
No full textComplementing wireless radio networks with free-space optics (FSO) achieves high data rates by modulating radio subcarriers over an optical carrier without expensive optical fiber cabling, enabling a pervasive platform for reaching underserved areas.In this paper, we review the main features of FSO for terrestrial and inter-satellite communications. Simulations of 1 Gbps data transmission through FSO links in both terrestrial and inter-satellite communications have been investigated to highlight potential atmospheric challenges in FS
Design of Excess 3 to BCD code converter using electro-optic effect of Mach-Zehnder Interferometers for efficient data transmission
Get PDFExcess 3 code is one of the most important codes used for efficient data storage and transmission. It is a non-weighted code and also known as self complimenting code. In this paper, a four bit optical Excess 3 to BCD code converter is proposed using electro-optic effect inside lithium-niobate based Mach-Zehnder interferometers (MZIs). The MZI structures have powerful capability to switching an optical input signal to a desired output port. The paper constitutes a mathematical description of the proposed device and thereafter simulation using MATLAB. The study is verified using beam propagation method (BPM).Dehradun Institute of Technology (Dehradun, India). Faculty Research Scheme (Ref. No.: DITU/R&D/2014/7/ECE
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
An optical synchronous up counter based on electro-optic effect of lithium niobate based Mach–Zehnder interferometers
Get PDFSequential circuits have the ability to store, retain and then retrieve information when needed at a later time. They act as storage elements and have memory. However, due to ever increasing demand of data rate, already existing electronic signal processing devices have become obsolete due to their large latency. To overcome the existing bottleneck, a 4-bit synchronous up counter using electro-optic effect of Mach–Zehnder interferometer has been proposed. The study is carried out by simulating the proposed device with beam propagation method
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
Author, publisher and bookseller : a tripartite synergy in Nigerian book industry
Get PDFThis work is about the roles of Author, Publisher and Bookseller in Book development in
Nigeria. The paper started by delving into the history of Book Publishing in Nigeria after
which it proceeded by defining who an author, a publisher, and a bookseller is and
expatiated on the indispensable roles of these key actors in Nigerian Book Industry and in
the emerging Information Society. Furthermore, the various constraints to book
development were identified while the paper advised on how the Book Industry can be
further promoted in Nigeria. However, the paper concluded and made recommendations
on how the Book sector can help in enhancing scholarship in the country
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