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Previously the author's (Lopez-Bravo et al., 2007) proposed the Load Balanced WASPNET Scheduler (LBWS), a novel scheduling approach for WASPNET optical packet switching (OPS) nodes. Unlike the original WASPNET description, LBWS is fully distributed and its computational cost is independent from switch size. Since it predicts packet delays at packet ingress based on a deterministic evolution of the...
This paper presents a comparative study of three metaheuristics: Genetic Algorithm (GA), ant Colony Optimization (AC) and Simulated Annealing (SA), implemented to solve the classical Traveling Salesman Problem (TSP). The efficiency of each approach is evaluated taking into account the execution time of the algorithm and the quality of the generated solution. Additionally, metrics of the program, including...
The aim of this work is to introduce and analyze a mixed finite element method of the eddy current problem in terms of the current density, when current intensities are prescribed as data. An axisymmetric form of this formulation is used to evaluate the response of a differential eddy current probe in nondestructive testing of tubes.
This paper presents a new development of an automated system for: stimulation, acquisition and the pupilar image processing (it includes segmentation and visualization in real time), issued from the photo-motor and consensual response of the iris. The physician can observe in the system interface: a graphic representation of the variation and change of speed of diameter and pupilar area as a function...
Recently, it has been proposed the use of speckle- tracking echography (STE) to study the left ventricle (LV) torsion dynamics, which would make LV torsion assessment more available in clinical and research cardiology. LV torsion has been described during exercise and in some sportsmen, but so far, its dynamics has not been studied in soccer players. The aims were to characterize and to compare LV...
With the increasing popularity of multimedia applications, video data represents a large portion of the traffic in modern networks. Consequently, adequate models of video traffic, characterized by a high burstiness and a strong positive correlation, are very important for the performance evaluation of network architectures and protocols. This paper presents a new model for traffic with persistent...
In this work, a preliminary study on the use of polarimetric persistent scatterers for differential interferometric applications within an urban environmental is presented. The PolSAR measurements campaign that the RSLab of UPC is carrying on in the village of Salient using an X-Band ground- based SAR sensor is first described. The work is then focused on the additional information the knowledge of...
This paper presents a preliminary study about the scattering properties of urban-like scatters based on simulated SAR images. A simple target performed by a box of gypsum located over a perfectly conducting flat plane is analyzed for different views in both ISAR and SAR fully-polarimetric modes. The results are analyzed with the Pauli decomposition theorem and they show that the scattering response...
This paper deals with the validation of a previously developed texture model for SAR data as well as its associated parameter estimation algorithm. The mentioned model is named the Anisotropic Gaussian Kernel (AGK) model and allows the description of the possibly nonstationary and anisotropic behaviour of texture on heterogeneous areas of SAR images. The parameter estimation performance is evaluated...
Thanks to their capability to cover large areas, in all weather conditions, during the day as well as during the night, spaceborne Synthetic Aperture Radar (SAR) techniques constitute an extremely promising alternative to traditional surveillance methods. Nevertheless, in order to assure further usability of SAR images, specific data mining tools are still to be developed to provide an efficient automatic...
A novel transpolarizing or crosspolarizing surface has been proposed to be applied in polarimetric SAR calibrating systems, like trihedrals, since they can not provide initially a crosspolar response. So the trans-surface has been designed and measured in an anechoic chamber, providing good results for normal incidence.
The identification of oil slicks on the ocean surface from SAR data requires quantitative sound models accounting for the most important characteristics (ocean spectrum, slick viscosity, slick shape, and so on). In this paper we present the implementation of an innovative SAR raw signal and image simulator, which is able to reproduce images relative to ocean surfaces covered by oil slicks with arbitrary...
This work presents an analytical study of the Quegan's PolSAR data calibration algorithm. As it shall be demonstrated, the solution proposed by Quegan based on certain approximations, gives in certain situations, biased crosstalk ratios u, v, w and z. An improved Quegan's calibration algorithm is proposed and tested.
Entropy, alpha and anisotropy (H/alpha/A) of the polarimetric target decomposition has been an effective and popular tool for polarimetric SAR image analysis and geophysical parameter estimation. However, multi-look processing can severely affects the values of these parameters. In this paper, we evaluate the bias problem in H/alpha/A due to insufficient averaging. We found that the estimated bias...
A new approach to filter speckle noise in multidimensional SAR data, based on the multiplicative-additive speckle noise model, is presented. This approach is based on processing the elements of the sample covariance matrix differently, according to the complex correlation coefficient. As it is demonstrated with experimental PolSAR data, the filter does not produce a loss of information, but an improvement...
In this paper, the wire-speed packet processing issue is studied for optical packet/burst switching (OPS/OBS) switching nodes as well as for wavelength-routing (WR) switching nodes. Some assumptions are made to obtain simple estimates of the requirements in terms of forwarding events per second. This is compared with the packet processing performance of electronic devices which implement this type...
The authors present a novel photonic material dubbed photonic glass, which is a solid, disordered, macroscopic assembly of monodisperse dielectric spheres. These spheres, whose diameter is of the order of the wavelength of the light, support Mie resonances and, as a result of a collective effect of these resonances, the photonic glass is expected to exhibit a resonant behaviour in the diffusion constant...
In this work we present both experimental and numerical studies of the optical properties of artificial opals. The staking of up to four layers of spheres may arise according to three different arrangements: face-centered cubic, hexagonal close-packed or double hexagonal close-packed. Our study shows that the transmission spectra features are characteristic of the type of stacking and thus, each color...
The environment can produce transient faults in digital circuits, especially nowadays with the new technology development. Fault injection has been widely used to evaluate the hardness degree of circuits in which fault tolerance is a requirement, like aerospace or automotive applications. The magnitude of the fault effects evaluation problem is computationally unaffordable, if an exhaustive test must...
DMX512 is the standard protocol used by lighting equipment in theatrical and entertainment data distribution systems. This paper describes a complete hardware and software solution for driving a high brightness 70 pixel RGB LED matrix from a computer and synchronized with environmental music, in addition to multiple running modes and possibilities achieved. Further possibilities of the developed device...
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