1,721,031 research outputs found
Tracking people in 3D using position, size and shape
No full textThis paper presents a prototype tracking system for tracking\ud
people in enclosed indoor environments where there is a\ud
high rate of occlusions. The system uses a stereo camera for\ud
acquisition, and is capable of disambiguating occlusions using\ud
a combination of depth map analysis, a two step ellipse\ud
fitting people detection process, the use of motion models\ud
and Kalman filters and a novel fit metric, based on computationally\ud
simple object statistics. Testing shows that our\ud
fit metric outperforms commonly used position based metrics\ud
and histogram based metrics, resulting in more accurate\ud
tracking of people
An improvement to the multiple window spectrogram using quadratic time-frequency distributions
No full textThis paper suggests an improvement to the multiple window (MW) spectrogram. The improvement was observed when redefining the MW spectrogram in a quadratic time– frequency distribution framework. This alternate view permits the MW method to be interpreted as an application of a single ambiguity domain filter, that consists of the average of each window sequence, to the ambiguity representation of the signal. In addition, the MW spectrogram can be improved by extending the ambiguity domain filter along the Doppler lag () axis. This enhanced MW spectrogram has lower variance and bias when estimating several signals in the presence of additive white Gaussian noise, while retaining the desirable properties of the spectrogram such as realness, non–negativity and minimal cross–terms
Newborn EEG simulation from nonlinear analysis
No full textIn this paper, we propose a novel method of simulating normal newborn EEG. The method is based on the results from the fractal dimension analysis of real EEG recordings. The fractal dimension analysis was done using the Higuchi method for fractal dimension estimation. Comparison of signals in the time domain, frequency domain and time-frequency domain between real and simulated signals show similarities validating the EEG simulator. This model can provide artefact free EEG signals for researchers so that algorithm parameters can be tuned or so that automatic EEG detection algorithms, such as seizure detection and epileptic spike detection, can be evaluated
A histogram-based electroencephalogram spike detection
No full textThis paper aims to improve the performance of a proposed electroencephalogram (EEG) spike detection technique. This technique accentuates the signature of spikes in the time domain signal using a nonlinear energy operator by amplifying high frequency activities such as spikes. The resulted signal is convolved with a smoothing window to reduce the effect of noise. Then, values of the resulted signal higher than a threshold value are considered as spikes. The instantaneous nature of the technique and its very low computation make it an ideal tool for spike detection. In this approach selection of the threshold value is crucial for the accuracy of the technique. This paper is aimed at improving the technique using a new approach for the threshold selection using the histogram of the smoothed nonlinear energy operator. The efficiency of the presented spike detection method has been evaluated using both synthetic signals and real newborn EEG. Results in this paper show that the proposed technique is superior to the original technique both in terms of sensitivity and selectivity
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
A sampling limit for the empirical mode decomposition
No full textThe aim of this paper is to investigate the effect of sampling on the empirical mode decomposition (EMD). To this end, an experiment utilising linear frequency modulated (LFM) signals was used to simulate different sampling rates. This experiment showed that as the frequency content of the signal (fc) approached the sampling frequency (fs) the EMD performed poorly due to poor amplitude resolution. This led to a definition of a sampling limit that was 5 times the Nyqvist rate (fs/10) to improve the performance of the EMD. Comparative simulation with this sampling limit was conducted on a simulated and a real world signal. The results exhibited significant improvement in intrinsic mode function (IMF) orthogonality, the distribution of IMF energy and IMF coherence
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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