Search results for "Computer Vision and Pattern Recognition"
showing 10 items of 997 documents
Tensor product multiresolution analysis with error control for compact image representation
2002
A class of multiresolution representations based on nonlinear prediction is studied in the multivariate context based on tensor product strategies. In contrast to standard linear wavelet transforms, these representations cannot be thought of as a change of basis, and the error induced by thresholding or quantizing the coefficients requires a different analysis. We propose specific error control algorithms which ensure a prescribed accuracy in various norms when performing such operations on the coefficients. These algorithms are compared with standard thresholding, for synthetic and real images.
A coupled Finite Volume–Smoothed Particle Hydrodynamics method for incompressible flows
2016
Abstract An hybrid approach is proposed which allows to combine Finite Volume Method (FVM) and Smoothed Particle Hydrodynamics (SPH). The method is based on the partitioning of the computational domain into a portion discretized with a structured grid of hexahedral elements (the FVM-domain ) and a portion filled with Lagrangian particles (the SPH-domain ), separated by an interface made of triangular elements. A smooth transition between the solutions in the FVM and SPH regions is guaranteed by the introduction of a layer of grid cells in the SPH-domain and of a band of virtual particles in the FVM one (both neighboring the interface), on which the hydrodynamic variables are obtained throug…
Distributed Learning Automata-based S-learning scheme for classification
2019
This paper proposes a novel classifier based on the theory of Learning Automata (LA), reckoned to as PolyLA. The essence of our scheme is to search for a separator in the feature space by imposing an LA-based random walk in a grid system. To each node in the grid, we attach an LA whose actions are the choices of the edges forming a separator. The walk is self-enclosing, and a new random walk is started whenever the walker returns to the starting node forming a closed classification path yielding a many-edged polygon. In our approach, the different LA attached to the different nodes search for a polygon that best encircles and separates each class. Based on the obtained polygons, we perform …
Robust stabilisation of 2D state-delayed stochastic systems with randomly occurring uncertainties and nonlinearities
2013
This paper is concerned with the state feedback control problem for a class of two-dimensional (2D) discrete-time stochastic systems with time-delays, randomly occurring uncertainties and nonlinearities. Both the sector-like nonlinearities and the norm-bounded uncertainties enter into the system in random ways, and such randomly occurring uncertainties and nonlinearities obey certain mutually uncorrelated Bernoulli random binary distribution laws. Sufficient computationally tractable linear matrix inequality–based conditions are established for the 2D nonlinear stochastic time-delay systems to be asymptotically stable in the mean-square sense, and then the explicit expression of the desired…
Mode-superposition correction method for deterministic and stochastic analysis of structural systems
2001
The role played by the modal analysis in the framework of structural dynamics is fundamental from both deterministic and stochastic point of view. However the accuracy obtained by means of the classical modal analysis is not always satisfactory. Therefore it is clear the importance of methods able to correct the modal response in such a way to obtain the required accuracy. Many methods have been proposed in the last years but they are meaningful only when the forcing function is expressed by an analytical function. Moreover in stochastic analysis they fail for white noise excitation. In the paper a method able to give a very accurate response for both deterministic and stochastic input is p…
A perturbation approach for the response of dynamically modified structural systems
1998
The problem of the structural analysis under changes of dynamical parameters is of particular interest. This is due to the fact that often the real structures are different from the predicted ones. In this paper, an unconditionally stable step-by-step procedure, able to evaluate the deterministic response of linear structures with modifications, is presented. The proposed procedure requires the evaluation of the transition matrix, which is the fundamental operator of the step-by-step solution, by means of a perturbation approach. This technique overcomes the difficulties connected with the evaluation of the eigenproperties of the modified structures usually required to obtain the transition…
On the classification of dynamical data streams using novel “Anti-Bayesian” techniques
2018
Abstract The classification of dynamical data streams is among the most complex problems encountered in classification. This is, firstly, because the distribution of the data streams is non-stationary, and it changes without any prior “warning”. Secondly, the manner in which it changes is also unknown. Thirdly, and more interestingly, the model operates with the assumption that the correct classes of previously-classified patterns become available at a juncture after their appearance. This paper pioneers the use of unreported novel schemes that can classify such dynamical data streams by invoking the recently-introduced “Anti-Bayesian” (AB) techniques. Contrary to the Bayesian paradigm, tha…
Life cycle assessment of roads: Material and process related energy savings
2018
The need for climate change mitigation calls for significant actions to match the sustainable development goals and, in this context, road construction and management play a relevant role (cf. EU Green Public Procurement Criteria for Road Design, Construction and Maintenance and Environmental Product Declarations - EPD). In such a context, the role of the Life Cycle Assessment (LCA) methodology is broadly recognized as a tool to quantify sustainability of processes and systems. This study aims at calculating the life-cycle energy and carbon footprint of a typical Italian urban road, including materials production, transportation, construction, maintenance, and rehabilitation. The LCA approa…
Computation of the field diffracted by a local surface defect: application to tip–sample interaction in the photon scanning tunneling microscope
1996
We use a method based on the Fourier transform of the electromagnetic field to compute the field diffracted by a local deformation of a plane boundary surface. We give a complete development of each step of the technique. To show the interaction that exists between the probe of a near-field optical microscope and the observed sample, we use the model of a truncated cone-shaped tip above a rectangular surface defect. We compute the electrical intensity along a line located between the tip and the local surface defect. We show the influence of the polarization of the incident wave and the effect of the position of the tip with respect to the position of the surface defect.
On the repeatability of the EMI for the monitoring of bonded joints
2015
We study the feasibility and the repeatability of the electromechanical impedance (EMI) method for the health monitoring of lightweight bonded joints. The EMI technique exploits the coupling between the displacement field and the potential field of a piezoelectric material, by attaching or embedding a piezoelectric transducer to the structure to be monitored. The sensor is excited by an external voltage and the electrical admittance which is the ratio between the electric current and the applied voltage is measured as it depends on the mechanical coupling between the transducer and the host structure. Owing to this interaction, the admittance may represent a signature for the health of the …