Modulo 2pi fringe orientation angle estimation by phase unwrapping with a regularized phase tracking algorithm

The fringe orientation angle provides useful information for many fringe-pattern-processing techniques. From a single normalized fringe pattern (background suppressed and modulation normalized), the fringe orientation angle can be obtained by computing the irradiance gradient and performing a further arctangent computation. Because of the 180 degrees ambiguity of the fringe direction, the orientation angle computed from the gradient of a single fringe pattern can be determined only modulo pi. Recently, several studies have shown that a reliable determination of the fringe orientation angle modulo 2pi is a key point for a robust demodulation of the phase from a single fringe pattern. We present an algorithm for the computation of the modulo 2pi fringe orientation angle by unwrapping the orientation angle obtained from the gradient computation with a regularized phase tracking method. Simulated as well as experimental results are presented.     

Dual holographic interferometry for measuring the three velocity components in a fluid plane

A technique that allows one to measure simultaneously the three velocity components in a fluid plane is presented. One obtains the quantitative information from only one holographic recording by combining two different reconstruction processes. As both processes use an interferometric comparison of two waves, we refer to this technique as dual holographic interferometry. The far-field fringe pattern that is obtained when reconstruction is made with an expanded laser beam allows one to determine the in-plane velocity components. The image-field fringe pattern that is obtained when a pointwise laser beam is used for reconstruction contains information about an out-of-plane velocity component. As the two reconstruction processes have different sensitivities, two different ways to combine them are proposed. The system has been demonstrated in a fluidlike solid object and in a convective flow.     

Performance index for quality response of dynamical systems

The use of performance indices to measure the quality response of dynamical systems is studied in this paper. A definition of a general performance index is proposed which is easy to compute, easy to interpret, and flexible enough to account for different cases commonly presented in practice. The index is tested over several dynamical responses obtained from different systems obtaining good results, in the sense that it is able to rank the behaviors from best to worse, compared with a pattern response.     

Freezing of Helium-4: Comparison of Different Density Functional Approaches

Solidification of superfluid helium-4 has been addressed within the framework of density functional theory. Early studies used a variational approach, approximating the density distribution in the solid phase by a sum of Gaussians on each lattice site. Recently, we performed an unconstrained minimization of the functional describing the helium system as reported by Ancilotto et al. (Phys. Rev. B, 72, 214522, 2005). At sufficiently high density, we find stable solid like solutions, which exhibit an anisotropic density profile around each lattice site. We compare these results to the previous variational approach, and attempt to improve the family of trial functions by adding a variational parameter to account for anisotropy.     

Mixed-mode crack propagation through reinforced concrete

This paper presents the results of a very recent experimental research program aimed at investigating mixed-mode fracture of reinforced concrete. The tests were designed so that only one single mixed-mode crack generates and propagates through the specimen, as opposed to the usual dense crack pattern found in most of the tests in scientific literature. The specimens were three-point-bend beams of three different sizes. They were notched asymmetrically and reinforced with various ratios of longitudinal and inclined reinforcement. These experiments may help to understand the mechanisms of crack initiation and propagation through reinforcing bars under mixed-mode load conditions.     

Methodological design and comparative evaluation of a MAS providing AmI

Researches on Ambient Intelligent and Ubiquitous Computing using wireless technologies have increased in the last years. In this work, we review several scenarios to define a multi-agent architecture that support the information needs of these new technologies, for heterogeneous domain. Our contribution consists of designing in a methodological way a Context Aware System (involving location services) using agents that can be used in very different domains. We describe all the steps followed in the design of the agent system. We apply a hybridizing methodology between GAIA and AUML. Additionally we propose a way to compare different agent architectures for Context Aware System using agent interactions. So, in this paper, we describe the assignment of weight values to agents interaction in two different MAS architectures for Context Aware problems solving different scenarios inspired in FIPA standard negotiation protocols.     

An audio enhancement system to improve intelligibility for social-awareness in HRI

Multimedia Tools and Applications - Improving the ability to interact through voice with a robot is still a challenge especially in real environments where multiple speakers coexist. This work has...     

Drinking Water Source Monitoring Using Early Warning Systems Based on Data Mining Techniques

Water Resources Management - Improving drinking water source monitoring is crucial for efficiently managing the drinking water treatment process and ensuring the delivery of safe water. Data mining...     

Attraction and Repulsion of Nucleons: Sources of Stellar Energy

The potential energy of a nuclide is enhanced by about 10 MeV per nucleon from the repulsion between like nucleons, and diminished by about 20 MeV per nucleon from the attraction between unlike nucleons. Nuclear stability results mostly from the interplay of these opposing forces, plus Coulomb repulsion of positive charges. Whereas fusion may be the primary mechanism by which first generation stars produce energy, repulsion between like nucleons may cause neutron emission from the collapsed core (neutron star) produced in a terminal supernova explosion and initiate luminosity in second generation stars that accrete on such objects. As noted earlier [1], the scarcity of solar neutrinos, the enrichment of light isotopes in the solar wind, and the presence of abundant short-lived nuclides and interlinked chemical and isotopic heterogeneities in the early solar system might also be explained if the Sun formed in this manner.