1,721,018 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
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
Radio-Location Techniques for Localization and Monitoring Applications. A study of localisation techniques, using OFDM system under adverse channel conditions and radio frequency identification for object identification and movement tracking
No full textA wide range of services and applications become possible when accurate position
information for a radio terminal is available. These include: location-based services;
navigation; safety and security applications. The commercial, industrial and military value
of radio-location is such that considerable research effort has been directed towards
developing related technologies, using satellite, cellular or local area network
infrastructures or stand-alone equipment.
This work studies and investigates two location techniques. The first one presents an
implementation scheme for a wideband transmission and direction finding system using
OFDM multi-carrier communications systems. This approach takes advantage of delay
discrimination to improve angle-of-arrival estimation in a multipath channel with high
levels of additive white Gaussian noise. A new methodology is interpreted over the multi carrier modulation scheme in which the simulation results of the estimated channel
improves the performance of OFDM signal by mitigating the effect of frequency offset
synchronization to give error-free data at the receiver, good angle of arrival accuracy and
improved SNR performance. The full system simulation to explore optimum values such
as channel estimation and AoA including the antenna array model and prove the
operational performance of the OFDM system as implemented in MATLAB.
The second technique proposes a low cost-effective method of tracking and monitoring
objects (examples: patient, device, medicine, document) by employing passive radio
frequency identification (RFID) systems. A multi-tag, (totalling fifty-six tags) with known
ID values are attached to the whole patient’s body to achieve better tracking and
monitoring precision and higher accuracy. Several tests with different positions and
movements are implemented on six patients. The aim is to be able to track the patient if
he/she is walking or sitting; therefore, the tests considered six possible movements for
the patient including walking, standing, sitting, resting, laying on the floor and laying on
the bed, these placements are important to monitor the status of the patient like if he
collapsed and fall on the ground so that the help will be quick. The collected data from
the RFID Reader in terms of Time Stamp, RSS, Tag ID, and a number of channels are
processed using the MATLAB code
The optimization of multiple antenna broadband wireless communications. A study of propagation, space-time coding and spatial envelope correlation in Multiple Input, Multiple Output radio systems
No full textThis work concentrates on the application of diversity techniques and space time block coding for future mobile wireless communications.
The initial system analysis employs a space-time coded OFDM transmitter over a multipath Rayleigh channel, and a receiver which uses a selection combining diversity technique. The performance of this combined scenario is characterised in terms of the bit error rate and throughput. A novel four element QOSTBC scheme is introduced, it is created by reforming the detection matrix of the original QOSTBC scheme, for which an orthogonal channel matrix is derived. This results in a computationally less complex linear decoding scheme as compared with the original QOSTBC. Space time coding schemes for three, four and eight transmitters were also derived using a Hadamard matrix.
The practical optimization of multi-antenna networks is studied for realistic indoor and mixed propagation scenarios. The starting point is a detailed analysis of the throughput and field strength distributions for a commercial dual band 802.11n MIMO radio operating indoors in a variety of line of sight and non-line of sight scenarios. The physical model of the space is based on architectural schematics, and realistic propagation data for the construction materials. The modelling is then extended and generalized to a multi-storey indoor environment, and a large mixed site for indoor and outdoor channels based on the Bradford University campus.
The implications for the physical layer are also explored through the specification of antenna envelope correlation coefficients. Initially this is for an antenna module configuration with two independent antennas in close proximity. An operational method is proposed using the scattering parameters of the system and which incorporates the intrinsic power losses of the radiating elements. The method is extended to estimate the envelope correlation coefficient for any two elements in a general (N,N) MIMO antenna array. Three examples are presented to validate this technique, and very close agreement is shown to exist between this method and the full electromagnetic analysis using the far field antenna radiation patterns
Advanced MIMO-OFDM technique for future high speed braodband wireless communications. A study of OFDM design, using wavelet transform, fractional fourier transform, fast fourier transform, doppler effect, space-time coding for multiple input, multiple output wireless communications systems
No full textThis work concentrates on the application of diversity techniques and space time block coding
for future high speed mobile wireless communications on multicarrier systems.
At first, alternative multicarrier kernels robust for high speed doubly-selective fading channel are
sought. They include the comparisons of discrete Fourier transform (DFT), fractional Fourier
transform (FrFT) and wavelet transform (WT) multicarrier kernels. Different wavelet types,
including the raised-cosine spectrum wavelets are implemented, evaluated and compared.
From different wavelet families, orthogonal wavelets are isolated from detailed evaluations and
comparisons as suitable for multicarrier applications. The three transforms are compared over a
doubly-selective channel with the WT significantly outperforming all for high speed conditions up
to 300 km/hr.
Then, a new wavelet is constructed from an ideal filter approximation using established wavelet
design algorithms to match any signal of interest; in this case under bandlimited criteria. The
new wavelet showed better performance than other traditional orthogonal wavelets.
To achieve MIMO communication, orthogonal space-time block coding, OSTBC, is evaluated
next. First, the OSTBC is extended to assess the performance of the scheme over extended
receiver diversity order. Again, with the extended diversity conditions, the OSTBC is
implemented for a multicarrier system over a doubly-selective fading channel. The MIMO-OFDM
systems (implemented using DFT and WT kernels) are evaluated for different operating
frequencies, typical of LTE standard, with Doppler effects. It was found that, during high mobile
speed, it is better to transmit OFDM signals using lower operating frequencies.
The information theory for the 2-transmit antenna OSTBC does not support higher order
implementation of multi-antenna systems, which is required for the future generation wireless
communications systems. Instead of the OSTBC, the QO-STBC is usually deployed to support
the design of higher order multi-antenna systems other than the 2-transmit antenna scheme.
The performances of traditional QO-STBC methods are diminished by some off-diagonal
(interference) terms such that the resulting system does not attain full diversity. Some methods
for eliminating the interference terms have earlier been discussed. This work follows the
construction of cyclic matrices with Hadamard matrix to derive QO-STBC codes construction
which are N-times better than interference free QO-STBC, where N is the number of transmit
antenna branches
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
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