59 resultados para Crowd Counting

em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"


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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Considering that counting the percentage of CD4 T lymphocytes can add prognostic information regarding patients infected with HIV, the aim of this study was to evaluate the percentage values of CD4+ T lymphocytes from 81 patients determined by flow cytometry and estimated by flow cytometry in conjunction with a hematology counter. Means were compared through the Student's t-test. Pearson's correlation was determined, and the agreement between results was tested by Bland-Altman. The level of significance was P < 0.05. It was found a significantly higher mean difference between the relative values of CD4+ T lymphocytes to the hematologic counter (P < 0.05), for all strata studied. Positive and significant correlations (P < 0.01) were found between the strata CD4 < 200 cells/mL (r = 0.93), between 200 and 500 cells/mL (r = 0.65), and >500 cells/mL (r = 0.81). The limits of agreement were 1.0 +/- 3.8% for the stratum of CD4 < 200 cells/mL, approximately 2.2 +/- 13.5% for the stratum of CD4 between 200 and 500 cells/mL, and approximately 6.2 +/- 20.4% for the stratum > 500 cells/mL. The differences in the percentages of CD4+ T lymphocytes obtained by different methodologies could lead to conflict when used in clinical decisions related to the treatment and care of people infected with HIV.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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We use a toy model to illustrate how to build effective theories for singular potentials. We consider a central attractive 1/r(2) potential perturbed by a 1/r(4) correction. The power-counting rule, an important ingredient of effective theory, is established by seeking the minimum set of short-range counterterms that renormalize the scattering amplitude. We show that leading-order counterterms are needed in all partial waves where the potential overcomes the centrifugal barrier, and that the additional counterterms at next-to-leading order are the ones expected on the basis of dimensional analysis. (C) 2008 Elsevier B.V. All rights reserved.

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This paper considers the role of automatic estimation of crowd density and its importance for the automatic monitoring of areas where crowds are expected to be present. A new technique is proposed which is able to estimate densities ranging from very low to very high concentration of people, which is a difficult problem because in a crowd only parts of people's body appear. The new technique is based on the differences of texture patterns of the images of crowds. Images of low density crowds tend to present coarse textures, while images of dense crowds tend to present fine textures. The image pixels are classified in different texture classes and statistics of such classes are used to estimate the number of people. The texture classification and the estimation of people density are carried out by means of self organising neural networks. Results obtained respectively to the estimation of the number of people in a specific area of Liverpool Street Railway Station in London (UK) are presented. (C) 1998 Elsevier B.V. Ltd. All rights reserved.

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The goal of this work is to assess the efficacy of texture measures for estimating levels of crowd densities ill images. This estimation is crucial for the problem of crowd monitoring. and control. The assessment is carried out oil a set of nearly 300 real images captured from Liverpool Street Train Station. London, UK using texture measures extracted from the images through the following four different methods: gray level dependence matrices, straight lille segments. Fourier analysis. and fractal dimensions. The estimations of dowel densities are given in terms of the classification of the input images ill five classes of densities (very low, low. moderate. high and very high). Three types of classifiers are used: neural (implemented according to the Kohonen model). Bayesian. and an approach based on fitting functions. The results obtained by these three classifiers. using the four texture measures. allowed the conclusion that, for the problem of crowd density estimation. texture analysis is very effective.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Human beings perceive images through their properties, like colour, shape, size, and texture. Texture is a fertile source of information about the physical environment. Images of low density crowds tend to present coarse textures, while images of dense crowds tend to present fine textures. This paper describes a new technique for automatic estimation of crowd density, which is a part of the problem of automatic crowd monitoring, using texture information based on grey-level transition probabilities on digitised images. Crowd density feature vectors are extracted from such images and used by a self organising neural network which is responsible for the crowd density estimation. Results obtained respectively to the estimation of the number of people in a specific area of Liverpool Street Railway Station in London (UK) are presented.

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The estimation of the number of people in an area under surveillance is very important for the problem of crowd monitoring. When an area reaches an occupation level greater than the projected one, people's safety can be in danger. This paper describes a new technique for crowd density estimation based on Minkowski fractal dimension. Fractal dimension has been widely used to characterize data texture in a large number of physical and biological sciences. The results of our experiments show that fractal dimension can also be used to characterize levels of people congestion in images of crowds. The proposed technique is compared with a statistical and a spectral technique, in a test study of nearly 300 images of a specific area of the Liverpool Street Railway Station, London, UK. Results obtained in this test study are presented.

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This paper presents a technique for real-time crowd density estimation based on textures of crowd images. In this technique, the current image from a sequence of input images is classified into a crowd density class. Then, the classification is corrected by a low-pass filter based on the crowd density classification of the last n images of the input sequence. The technique obtained 73.89% of correct classification in a real-time application on a sequence of 9892 crowd images. Distributed processing was used in order to obtain real-time performance. © Springer-Verlag Berlin Heidelberg 2005.

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Many epidemiological studies and clinical trials have been performed concerning actinic keratoses. The most eligible endpoint in the majority of articles is counting of actinic keratoses before and after treatments, nevertheless some authors support that this is not a reliable form of evaluation. The aim of this study was to evaluate the actinic keratoses counting by various raters and suggest approaches to increase the reliability. Cross-sectional study: forty-three patients were evaluated by four raters (inter- and intra-rater assessment) on the face and forearms. The mean actinic keratoses counts on the face and forearms were 7.7 and 9.1. The overall agreement among the raters for the facial and forearm actinic keratoses was 0.74 and 0.77. The intra-rater assessment showed high rates of agreement for the face (ICC = 0.93) and forearms (ICC = 0.83). Higher agreement occurred when counting up to five lesions. Four raters led to increased measurement variability and loss of reliability. Higher rates of agreement may be achieved with small number of lesions, limitation and/or segmentation of body areas to reduce their number, in AK prevention designs, are strategies that may lead to a greater reliability of these measurements. © 2013 Springer-Verlag Berlin Heidelberg.

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Objective: To evaluate if the total bacterial count of vaginal samples with bacterial vaginosis assessed by flow cytometry influences the response to treatment with metronidazol. Methods: In this cross-sectional study, 273 low-risk reproductive aged women were enrolled. Vaginal samples were taken to evaluate the pattern of vaginal flora according to Nugent’s criteria, as well as the presence of trichomoniasis and candidosis. Cases identified of bacterial vaginosis were treated with metronidazole and controlled after 45 days. Cervical infection by Chlamydia trachomatis and Neisseria gonorrhoeae were also assessed. Flow cytometry for total bacterial counting was performed in propidium iodide stained cervicovaginal samples, using fluorescent beads at a known concentration. Non-parametric Mann-Whitney test was used to compare total bacterial count between groups of interest, at p<0.05. Results: From the total of 273 women enrolled, 50 were excluded as they presented at least one of the infections investigated. Bacterial vaginosis was detected in 79 women (35.4%), of which 33 (41.8%) returned for re-evaluation after treatment, being 21 cases successfully treated and 12 with persistent abnormal vaginal flora. Flow cytometric data showed that total bacterial counting does not differ between normal flora and bacterial vaginosis samples (p=0.14). Also, no difference was found between the cases of treated and persistent bacterial vaginosis (p=0.48). Conclusion: Total bacterial counting does not influence the response to metronidazole treatment of bacterial vaginosis

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Power-counting arguments are used to organize the interactions contributing to the NN-->d pi,pn pi reactions near threshold. We estimate the contributions from the three formally leading mechanisms: the Weinberg-Tomozawa (WT) term, the impulse term, and the Delta-excitation mechanism. Subleading but potentially large mechanisms, including S-wave pion rescattering, the Galilean correction to the WT term, and short-ranged contributions are also examined. The WT term is shown to be numerically the largest, and the other contributions are found to approximately cancel. Similarly to the reaction pp-->pp pi(0), the computed cross sections are considerably smaller than the data. We discuss possible origins of this discrepancy.