2,906 research outputs found

    Automatic Face Recognition System Based on Local Fourier-Bessel Features

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    We present an automatic face verification system inspired by known properties of biological systems. In the proposed algorithm the whole image is converted from the spatial to polar frequency domain by a Fourier-Bessel Transform (FBT). Using the whole image is compared to the case where only face image regions (local analysis) are considered. The resulting representations are embedded in a dissimilarity space, where each image is represented by its distance to all the other images, and a Pseudo-Fisher discriminator is built. Verification test results on the FERET database showed that the local-based algorithm outperforms the global-FBT version. The local-FBT algorithm performed as state-of-the-art methods under different testing conditions, indicating that the proposed system is highly robust for expression, age, and illumination variations. We also evaluated the performance of the proposed system under strong occlusion conditions and found that it is highly robust for up to 50% of face occlusion. Finally, we automated completely the verification system by implementing face and eye detection algorithms. Under this condition, the local approach was only slightly superior to the global approach.Comment: 2005, Brazilian Symposium on Computer Graphics and Image Processing, 18 (SIBGRAPI

    Post-activation Potentiation In Propulsive Force After Specific Swimming Strength Training

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    We investigated whether a conditioning activity (8x12.5m with 2.5min-interval using both hand paddles and parachute) induced post-activation potentiation in swimming propulsive force and whether a swimmer's force level affected a post-activation potentiation response. 8 competitive swimmers (5 males and 3 females, age: 18.4 +/- 1.3 years; IPS=796 +/- 56) performed a 10s maximum tethered swimming test 8 and 4min before (the highest value was considered as PRE), and 2.5 and 6.5min after (POST1 and POST2, respectively) the conditioning activity. Rate of force development was not affected, but peak force in POST1 (p=0.02) and impulse in both POST1 (p=0.007) and POST2 (p=0.004) were reduced. Possibly the conditioning activity induced greater fatigue than post-activation potentiation benefits. For instance, the number of repetitions might have been excessive, and rest intervals between the conditioning activity and POST1 and POST2 were possibly too short. There were positive correlations between PRE peak force and changes in peak force and rate of force development. Although conditioning activity was detrimental, positive correlations suggest that weaker swimmers experience a deterioration of performance more than the stronger ones. This conditioning activity is not recommended for swimmers with the current competitive level before a competitive event.37431331

    On the consistency of a repulsive gravity phase in the early Universe

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    We exploit the possibility of existence of a repulsive gravity phase in the evolution of the Universe. A toy model with a free scalar field minimally coupled to gravity, but with the "wrong sign" for the energy and negative curvature for the spatial section, is studied in detail. The background solutions display a bouncing, non-singular Universe. The model is well-behaved with respect to tensor perturbations. But, it exhibits growing models with respect to scalar perturbations whose maximum occurs in the bouncing. Hence, large inhomogeneties are produced. At least for this case, a repulsive phase may destroy homogeneity, and in this sense it may be unstable. A newtonian analogous model is worked out; it displays qualitatively the same behaviour. The generality of this result is discussed. In particular, it is shown that the addition of an attractive radiative fluid does not change essentially the results. We discuss also a quantum version of the classical repulsive phase, through the Wheeler-de Witt equation in mini-superspace, and we show that it displays essentially the same scenario as the corresponding attractive phase.Comment: Latex file, 15 pages, 7 figures. There is a new figure, a new section and some other minor correction

    Boundary Integral Equations for Modeling Arbitrary Flaw Geometries in Electric Current Injection NDE

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    The Electric Current Injection (ECI) method of nondestructive evaluation is applied to materials that are electrically conductive but not magnetically permeable, such as aluminum, magnesium, and titanium. It consists of detecting current-flow anomalies due to voids, nonmetallic inclusions and open cracks in the conducting material, through distortions introduced in the magnetic field generated by the sample [1]

    EVALUATION OF ACCIDENTS WITH DOMINO EFFECT IN LPG STORAGE AREAS

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    The term domino effect denotes a chain of accidents, or situations, in which a fire/explosion load generated by an accident in one unit in an industry causes secondary and higher order accidents in other units. Such chains of accidents have a greater propensity to cause damage than stand-alone accidents. Most of the past risk assessment studies deal with accident in a single industry, more so in one of the units of an industry. But, often, accident in one unit causes a secondary accident in a nearby unit, which in turn may trigger a tertiary accident, and so on. The probability of occurrence and adverse impacts of such domino or cascading effects are increasing due to increasing congestion in industrial complexes and increasing density of human population around such complexes. Accidents with domino effect are seldom studied. LPG storage areas could produce the worst possible consequences in the event of an unforeseen incident. This work illustrates the application of models to evaluate the impacts of events with fire and explosion in LPG tanks on other similar units in the park and the possibility of occurrence of a domino effect. The criteria for occurrence of accidents with domino effect adopted in this work were 37.5 kW/m2 in case of fire radiation and an overpressure of 0.7 atm in explosion cases in a receptor body. The spacing between LPG tanks was evaluated. The results show that such spacing is minimal and does not represent, as it should, a parameter indicating a safe distance able to prevent the propagation of an accident with domino effect

    Tillering Dynamics of \u3ci\u3ePanicum maximum\u3c/i\u3e Jacq. cv. Tanzania-1 After Grazing

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    Tillering dynamics and tiller dry matter weight from Tanzania grass (Panicum maximum cv. Tanzania-1) were evaluated in two post-grazing stubbles (High Post-grazing Stubble – HPS-3.6 t of DM/ha and Low Post-grazing Stubble – LPS-2.3 t of DM/ha). There was no difference between post-grazing stubbles for decapitated axillary and basal remainder and new axillary tillers. The LPS presented greater number of new basal tillers. The rate of appearance of new basal and axillary tillers decreased with time after grazing. There were differences between the treatments on tiller dry matter weight, and greater values were found in the high post-graze stubble

    Optimization of supply diversity for the self-assembly of simple objects in two and three dimensions

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    The field of algorithmic self-assembly is concerned with the design and analysis of self-assembly systems from a computational perspective, that is, from the perspective of mathematical problems whose study may give insight into the natural processes through which elementary objects self-assemble into more complex ones. One of the main problems of algorithmic self-assembly is the minimum tile set problem (MTSP), which asks for a collection of types of elementary objects (called tiles) to be found for the self-assembly of an object having a pre-established shape. Such a collection is to be as concise as possible, thus minimizing supply diversity, while satisfying a set of stringent constraints having to do with the termination and other properties of the self-assembly process from its tile types. We present a study of what we think is the first practical approach to MTSP. Our study starts with the introduction of an evolutionary heuristic to tackle MTSP and includes results from extensive experimentation with the heuristic on the self-assembly of simple objects in two and three dimensions. The heuristic we introduce combines classic elements from the field of evolutionary computation with a problem-specific variant of Pareto dominance into a multi-objective approach to MTSP.Comment: Minor typos correcte

    Drug Hypersensitivity Quality of Life Questionnaire: validation procedures and first results of the Portuguese version

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    Background: Hypersensitivity reactions to drugs are unpredictable and can be very complex and severe, even life threatening. Assess its impact on patient’s health related quality of life (HRQoL) is crucial. The Drug Hypersensitivity Quality of Life Questionnaire (DrHy-Q) is the only validated disease-specific HRQoL questionnaire. We aimed to translate and cross-cultural validate the DrHy-Q to the Portuguese population. It was also our purpose to determine the impact of drug hypersensitivity on patients’ HRQoL. Methods: The translation and cross-cultural adaptation of the DrHy-Q to Portuguese was performed according to standards. Reliability of the DrHy-Q Portuguese version was assessed in terms of internal consistency and test–retest reliability. Structural validity, divergent validity (with a generic health related QoLQ-PGWBI) and discriminant validity were also evaluated. Forty patients accepted to participate in the validation phase. The Portuguese version of the DrHy-Q was applied to 260 consecutively adult patients, studied in our Department for suspected drug hypersensitivity. Results: The Portuguese DrHy-Q showed adequate internal consistency (Cronbach’s ¿ = 0.938), good test–retest reliability [ICC = 0.713 (95% CI 0.488–0.850] and one-dimensional structure. No significant correlation was found between the DrHy-Q and the PGWBI total scores (r = - 0.010, p = 0.957). Two hundred of patients completed the study: 78.5% female; mean age = 44 ± 15 years. Mean DrHy-Q score was 36.8 ± 12.6. Two clinical factors significantly predict DrHy-Q total score: clinical manifestations and number of suspected drugs. Patients with anaphylaxis (ß = 11.005; 95% CI 5.523; 16.487), urticaria/angioedema (ß = 7.770; 95% CI 2.600; 12.940) and other manifestations (ß = 7.948; 95% CI 1.933; 13.962) are more likely to have higher DrHy-Q total score than patients with maculopapular exanthema. Patients with = 2 suspected drugs are also more likely to have worse QoL (ß = 7.927; 95% CI 3.687; 12.166). Conclusion: The Portuguese version of DrHy-Q revealed adequate validity and reliability, indicating that it is appropriate to assess the impact of drug hypersensitivity on patients’ HRQoL, providing data for a better comprehension and management of our patients. Moreover, our results highlight that the severity of the drug hypersensitivity reaction and the number of suspected drugs have impact on patient’s DrHy-QoL
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