Search results for "NOISE"
showing 10 items of 1375 documents
Global Synchronization via Homogeneous Nucleation in Oscillating Surface Reactions
1999
The mechanism leading to globally synchronized oscillations in the $\mathrm{CO}+{\mathrm{O}}_{2}/\mathrm{Pt}\left(110\right)$ reaction system is investigated by means of Monte Carlo simulations. The model considers the reconstruction of the surface via phase border propagation and spontaneous phase nucleation. The reason for global oscillations turns out to be the spontaneous phase nucleation. This nucleation, which is modeled as a weak noise process, results in a random creation of dynamic defects and leads to global synchronization via stochastic resonance. The mechanism of global coupling via the gas phase, as it is proposed to date, does not occur.
Approximation of Continuous Media Models for Granular Systems Using Cellular Automata
2004
In this paper a new cellular automata model suitable for granular systems simulation is presented. The proposed model is shown to be equivalent to a particularization of the well known BCRE model of granular systems and a correspondence between the parameters of the presented model and the BCRE model is also set, allowing to fit these parameters for a given system. The model has the advantage over other cellular automata models of being more realistic in the behavior of the surface of heaps and slopes. The dynamics of the CA is analyzed in order to confirm that it also has one of the most important features of these systems, 1/f noise.
Multiresolution Analysis for Irregular Meshes
2003
International audience; The concept of multiresolution analysis applied to irregular meshes has become more and more important. Previous contributions proposed a variety of methods using simplification and/or subdivision algorithms to build a mesh pyramid. In this paper, we propose a multiresolution analysis framework for irregular meshes with attributes. Our framework is based on simplification and subdivision algorithms to build a mesh pyramid. We introduce a surface relaxation operator that allows to build a non-uniform subdivision for a low computational cost. Furthermore, we generalize the relaxationoperator to attributes such as color, texture, temperature, etc. The attribute analysis…
Entire reflective object surface structure understanding based on reflection motion estimation
2015
An sub-segmentation method for the reflective surface structure understanding.The use of reflection motion features as spatiotemporal coherence for video segmentation.Straightforward implementation.A building block for object recognition. The presence of reflection on a surface has been a long-standing problem for object recognition since it brings negative effects on object's color, texture and structural information. Because of that, it is not a trivial task to recognize the surface structure affected by the reflection, especially when the object is entirely reflective. Most of the cases, reflection is considered as noise. In this paper, we propose a novel method for entire reflective obj…
PROPOSALS FOR ENVIRONMENTAL NOISE MANAGEMENT BOOST AT A NATIONAL LEVEL IN THE EUROPEAN UNION MEMBER STATES
2017
Environmental noise is currently becoming one of the most dominant types of environmental pollution. The effects of environmental noise closely correlate with quality of life especially regarding the physical and psychological health of inhabitants, social and economic costs, and thus also impacting the sustainable development of a country. Environmental noise management, therefore, is one of the most necessary and exigent aspects of environmental pollution management governance. The management of noise need to be developed in a comprehensive, integrative and cross-sectorial way, and appropriate methods and approaches for the management of overall noise impacts need to be found to deal with…
Analysis of discrete and continuous distributions of ventilatory time constants from dynamic computed tomography.
2005
In this study, an algorithm was developed to measure the distribution of pulmonary time constants (TCs) from dynamic computed tomography (CT) data sets during a sudden airway pressure step up. Simulations with synthetic data were performed to test the methodology as well as the influence of experimental noise. Furthermore the algorithm was applied to in vivo data. In five pigs sudden changes in airway pressure were imposed during dynamic CT acquisition in healthy lungs and in a saline lavage ARDS model. The fractional gas content in the imaged slice (FGC) was calculated by density measurements for each CT image. Temporal variations of the FGC were analysed assuming a model with a continuous…
Surpassing digital holography limits by lensless object scanning holography.
2012
We present lensless object scanning holography (LOSH) as a fully lensless method, capable of improving image quality in reflective digital Fourier holography, by means of an extremely simplified experimental setup. LOSH is based on the recording and digital post-processing of a set of digital lensless holograms and results in a synthetic image with improved resolution, field of view (FOV), signal-to-noise ratio (SNR), and depth of field (DOF). The superresolution (SR) effect arises from the generation of a synthetic aperture (SA) based on the linear movement of the inspected object. The same scanning principle enlarges the object FOV. SNR enhancement is achieved by speckle suppression and c…
Synthetic aperture superresolution by speckle pattern projection.
2009
We propose a method for increasing the resolution of an aperture limited optical system by illuminating the input with a speckle pattern. The high resolution of the projected speckle pattern demodulates the high frequencies of the sample and permits its passage through the system aperture. A decoding provides the superresolved image. The speckle pattern can be generated in a simple manner in contrast with other structured light superresolution methods. The method is demonstrated in microscopy test images.
Aiding phase unwrapping by increasing the number of residues in two-dimensional wrapped-phase distributions.
2015
In phase unwrapping residues are points of locally inconsistent phase that occur within a wrapped-phase map, which are usually regarded as being problematic for phase-unwrapping algorithms. Real phase maps typically contain a number of residues that are approximately proportional to the subsequent difficulty in unwrapping the phase distribution. This paper suggests the radical use of the discrete Fourier transform to actually increase the number of residues in 2D phase-wrapped images that contain discontinuities. Many of the additional residues that are artificially generated by this method are located on these discontinuities. For example, in fringe projection systems, such phase discontin…
Integration of GMR sensors with different technologies
2016
Less than thirty years after the giant magnetoresistance (GMR) effect was described, GMR sensors are the preferred choice in many applications demanding the measurement of low magnetic fields in small volumes. This rapid deployment from theoretical basis to market and state-of-the-art applications can be explained by the combination of excellent inherent properties with the feasibility of fabrication, allowing the real integration with many other standard technologies. In this paper, we present a review focusing on how this capability of integration has allowed the improvement of the inherent capabilities and, therefore, the range of application of GMR sensors. After briefly describing the …