10 resultados para dynamic user behavior

em Biblioteca Digital da Produção Intelectual da Universidade de São Paulo


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Ubiquitous Computing promises seamless access to a wide range of applications and Internet based services from anywhere, at anytime, and using any device. In this scenario, new challenges for the practice of software development arise: Applications and services must keep a coherent behavior, a proper appearance, and must adapt to a plenty of contextual usage requirements and hardware aspects. Especially, due to its interactive nature, the interface content of Web applications must adapt to a large diversity of devices and contexts. In order to overcome such obstacles, this work introduces an innovative methodology for content adaptation of Web 2.0 interfaces. The basis of our work is to combine static adaption - the implementation of static Web interfaces; and dynamic adaptation - the alteration, during execution time, of static interfaces so as for adapting to different contexts of use. In hybrid fashion, our methodology benefits from the advantages of both adaptation strategies - static and dynamic. In this line, we designed and implemented UbiCon, a framework over which we tested our concepts through a case study and through a development experiment. Our results show that the hybrid methodology over UbiCon leads to broader and more accessible interfaces, and to faster and less costly software development. We believe that the UbiCon hybrid methodology can foster more efficient and accurate interface engineering in the industry and in the academy.

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The viscosity of AOT/water/decane water-in-oil microemulsions exhibits a well-known maximum as a function of water/AOT molar ratio, which is usually attributed to increased attractions among nearly spherical droplets. The maximum can be removed by adding salt or by changing the oil to CCl4. Systematic small-angle X-ray scattering (SAXS) measurements have been used to monitor the structure of the microemulsion droplets in the composition regime where the maximum appears. On increasing the droplet concentration, the scattering intensity is found to scale with the inverse of the wavevector, a behavior which is consistent with cylindrical structures. The inverse wavevector scaling is not observed when the molar ratio is changed, moving the system away from the value corresponding to the viscosity maximum. It is also not present in the scattering from systems containing enough added salt to essentially eliminate the viscosity maximum. An asymptotic analysis of the SAXS data, complemented by some quantitative modeling, is consistent with cylindrical growth of droplets as their concentration is increased. Such elongated structures are familiar from related AOT systems in which the sodium counterion has been exchanged for a divalent one. However, the results of this study suggest that the formation of non-spherical aggregates at low molar ratios is an intrinsic property of AOT.

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This paper presents an optimum user-steered boundary tracking approach for image segmentation, which simulates the behavior of water flowing through a riverbed. The riverbed approach was devised using the image foresting transform with a never-exploited connectivity function. We analyze its properties in the derived image graphs and discuss its theoretical relation with other popular methods such as live wire and graph cuts. Several experiments show that riverbed can significantly reduce the number of user interactions (anchor points), as compared to live wire for objects with complex shapes. This paper also includes a discussion about how to combine different methods in order to take advantage of their complementary strengths.

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Nickel oxide nonoparticles successfully synthesized by a polymer percursor method are studied in this work. The analysis of X-ray powder diffraction data provides a mean crystallite size of 22 +/- 2 nm which is in a good agreement with the mean size estimated from transmission electron microscopy images. Whereas the magnetization (M) vs. magnetic field (H) curve obtained at 5 K is consistent with a ferromagnetic component which coexists with an antiferromagnetic component, the presence of two peaks in the zero-field-cooled trace suggests the occurrence of two blocking process. The broad maximum at high temperature was associated with the thermal relaxation of uncompensated spins at the particle core and the low temperature peak was assigned to the freeze of surface spins clusters. Static and dynamic magnetic results suggest that the correlations of surface spins clusters show a spin-glass-like below T-g = 7.3 +/- 0.1 K with critical exponents zv = 9.7 +/- 0.5 and beta = 0.7 +/- 0.1, which are consistent with typical reported for spin-glass systems. (C) 2012 Elsevier B.V. All rights reserved.

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Background: Changes in heart rate during rest-exercise transition can be characterized by the application of mathematical calculations, such as deltas 0-10 and 0-30 seconds to infer on the parasympathetic nervous system and linear regression and delta applied to data range from 60 to 240 seconds to infer on the sympathetic nervous system. The objective of this study was to test the hypothesis that young and middle-aged subjects have different heart rate responses in exercise of moderate and intense intensity, with different mathematical calculations. Methods: Seven middle-aged men and ten young men apparently healthy were subject to constant load tests (intense and moderate) in cycle ergometer. The heart rate data were submitted to analysis of deltas (0-10, 0-30 and 60-240 seconds) and simple linear regression (60-240 seconds). The parameters obtained from simple linear regression analysis were: intercept and slope angle. We used the Shapiro-Wilk test to check the distribution of data and the "t" test for unpaired comparisons between groups. The level of statistical significance was 5%. Results: The value of the intercept and delta 0-10 seconds was lower in middle age in two loads tested and the inclination angle was lower in moderate exercise in middle age. Conclusion: The young subjects present greater magnitude of vagal withdrawal in the initial stage of the HR response during constant load exercise and higher speed of adjustment of sympathetic response in moderate exercise.

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In this paper, the combination of the Dynamic Threshold (DT) voltage technique with a non-planar structure is experimentally studied in triple-gate FinFETs. The drain current, transconductance, resistance, threshold voltage, subthreshold swing and Drain Induced Barrier Lowering (DIBL) will be analyzed in the DT mode and the standard biasing configuration. Moreover, for the first time, the important figures of merit for the analog performance such as transconductance-over-drain current, output conductance. Early voltage and intrinsic voltage gain will be studied experimentally and through three-dimensional (3-D) numerical simulations for different channel doping concentrations in triple-gate DTMOS FinFETs. The results indicate that the DTMOS FinFETs always yield superior characteristic; and larger transistor efficiency. In addition, DTMOS devices with a high channel doping concentration exhibit much better analog performance compared to the normal operation mode, which is desirable for high performance low-power/low-voltage applications. (C) 2011 Elsevier Ltd. All rights reserved.

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This paper presents preliminary results to determine small displacements of a global positioning system (GPS) antenna fastened to a structure using only one L1 GPS receiver. Vibrations, periodic or not, are common in large structures, such as bridges, footbridges, tall buildings, and towers under dynamic loads. The behavior in time and frequency leads to structural analysis studies. The hypothesis of this article is that any large structure that presents vibrations in the centimeter-to-millimeter range can be monitored by phase measurements of a single L1 receiver with a high data rate, as long as the direction of the displacement is pointing to a particular satellite. Within this scenario, the carrier phase will be modulated by antenna displacement. During a period of a few dozen seconds, the relative displacement to the satellite, the satellite clock, and the atmospheric phase delays can be assumed as a polynomial time function. The residuals from a polynomial adjustment contain the phase modulation owing to small displacements, random noise, receiver clock short time instabilities, and multipath. The results showed that it is possible to detect displacements of centimeters in the phase data of a single satellite and millimeters in the difference between the phases of two satellites. After applying a periodic nonsinusoidal displacement of 10 m to the antenna, it is clearly recovered in the difference of the residuals. The time domain spectrum obtained by the fast Fourier transform (FFT) exhibited a defined peak of the third harmonic much more than the random noise using the proposed third-degree polynomial model. DOI: 10.1061/(ASCE)SU.1943-5428.0000070. (C) 2012 American Society of Civil Engineers.

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Understanding how magnetic materials respond to rapidly varying magnetic fields, as in dynamic hysteresis loops, constitutes a complex and physically interesting problem. But in order to accomplish a thorough investigation, one must necessarily consider the effects of thermal fluctuations. Albeit being present in all real systems, these are seldom included in numerical studies. The notable exceptions are the Ising systems, which have been extensively studied in the past, but describe only one of the many mechanisms of magnetization reversal known to occur. In this paper we employ the Stochastic Landau-Lifshitz formalism to study high-frequency hysteresis loops of single-domain particles with uniaxial anisotropy at an arbitrary temperature. We show that in certain conditions the magnetic response may become predominantly out-of-phase and the loops may undergo a dynamic symmetry loss. This is found to be a direct consequence of the competing responses due to the thermal fluctuations and the gyroscopic motion of the magnetization. We have also found the magnetic behavior to be exceedingly sensitive to temperature variations, not only within the superparamagnetic-ferromagnetic transition range usually considered, but specially at even lower temperatures, where the bulk of interesting phenomena is seen to take place. (C) 2011 Elsevier B.V. All rights reserved.

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In this paper, we present a novel approach to perform similarity queries over medical images, maintaining the semantics of a given query posted by the user. Content-based image retrieval systems relying on relevance feedback techniques usually request the users to label relevant/irrelevant images. Thus, we present a highly effective strategy to survey user profiles, taking advantage of such labeling to implicitly gather the user perceptual similarity. The profiles maintain the settings desired for each user, allowing tuning of the similarity assessment, which encompasses the dynamic change of the distance function employed through an interactive process. Experiments on medical images show that the method is effective and can improve the decision making process during analysis.

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The conjugated frustrated phosphane/borane Lewis pairs formed by 1,1-carboboration of a substituted diphenylphosphino acetylene, undergo a synergistic 1,1-addition reaction to n-butyl isocyanide with formation of new B-C and P-C bonds to the former isonitrile carbon atom. Using tert-butyl isocyanide dynamic behaviour between the isocyanide-[B] adduct and the 1,1-addition product formation was observed in solution. The different modes of isocyanide binding to the FLPs in the solid state were characterized using X-ray crystal structure analyses and comprehensive 11B and 31P solid-state magicangle- spinning (MAS-) NMR experiments. The free FLP, the Lewis adduct at the borane group, and the cyclic product resulting from isocyanide addition to both reaction centers, can be differentiated via 11B and 31P isotropic chemical shifts, 11B nuclear electric quadrupole coupling constants, isotropic indirect 11B-31P spin-spin coupling constants, and 11B...31P internuclear distances measured by rotational echo double resonance.